Dissertations / Theses on the topic 'Bagasse'

Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: The world’s depleting fossil fuels and increasing greenhouse gas emissions have given rise to much research into renewable and cleaner energy. Biomass is unique in providing the only renewable source of fixed carbon. Agricultural residues such as Sugarcane Bagasse (SB) are feedstocks for ‘second generation fuels’ which means they do not compete with production of food crops. In South Africa approximately 6 million tons of raw SB is produced annually, most of which is combusted onsite for steam generation. In light of the current interest in bio-fuels and the poor utilization of SB as energy product in the sugar industry, alternative energy recovery processes should be investigated. This study looks into the thermochemical upgrading of SB by means of pyrolysis. Biomass pyrolysis is defined as the thermo-chemical decomposition of organic materials in the absence of oxygen or other reactants. Slow Pyrolysis (SP), Vacuum Pyrolysis (VP), and Fast Pyrolysis (FP) are studied in this thesis. Varying amounts of char and bio-oil are produced by the different processes, which both provide advantages to the sugar industry. Char can be combusted or gasified as an energy-dense fuel, used as bio-char fertilizer, or upgraded to activated carbon. High quality bio-oil can be combusted or gasified as a liquid energy-dense fuel, can be used as a chemical feedstock, and shows potential for upgrading to transport fuel quality. FP is the most modern of the pyrolysis technologies and is focused on oil production. In order to investigate this process a 1 kg/h FP unit was designed, constructed and commissioned. The new unit was tested and compared to two different FP processes at Forschungszentrum Karlsruhe (FZK) in Germany. As a means of investigating the devolatilization behaviour of SB a Thermogravimetric Analysis (TGA) study was conducted. To investigate the quality of products that can be obtained an experimental study was done on SP, VP, and FP. Three distinct mass loss stages were identified from TGA. The first stage, 25 to 110°C, is due to evaporation of moisture. Pyrolitic devolatilization was shown to start at 230°C. The final stage occurs at temperatures above 370°C and is associated with the cracking of heavier bonds and char formation. The optimal decomposition temperatures for hemicellulose and cellulose were identified as 290°C and 345°C, respectively. Lignin was found to decompose over the entire temperature range without a distinct peak. These results were confirmed by a previous study on TGA of bagasse. SP and VP of bagasse were studied in the same reactor to allow for accurate comparison. Both these processes were conducted at low heating rates (20°C/min) and were therefore focused on char production. Slow pyrolysis produced the highest char yield, and char calorific value. Vacuum pyrolysis produced the highest BET surface area chars (>300 m2/g) and bio-oil that contained significantly less water compared to SP bio-oil. The short vapour residence time in the VP process improved the quality of liquids. The mechanism for pore formation is improved at low pressure, thereby producing higher surface area chars. A trade-off exists between the yield of char and the quality thereof. FP at Stellenbosch University produced liquid yields up to 65 ± 3 wt% at the established optimal temperature of 500°C. The properties of the bio-oil from the newly designed unit compared well to bio-oil from the units at FZK. The char properties showed some variation for the different FP processes. At the optimal FP conditions 20 wt% extra bio-oil is produced compared to SP and VP. The FP bio-oil contained 20 wt% water and the calorific value was estimated at 18 ± 1 MJ/kg. The energy per volume of FP bio-oil was estimated to be at least 11 times more than dry SB. FP was found to be the most effective process for producing a single product with over 60% of the original biomass energy. The optimal productions of either high quality bio-oil or high surface area char were found to be application dependent.
AFRIKAANSE OPSOMMING: As gevolg van die uitputting van fossielbrandstofreserwes, en die toenemende vrystelling van kweekhuisgasse word daar tans wêreldwyd baie navorsing op hernubare en skoner energie gedoen. Biomassa is uniek as die enigste bron van hernubare vaste koolstof. Landbouafval soos Suikerriet Bagasse (SB) is grondstowwe vir ‘tweede generasie bio-brandstowwe’ wat nie die mark van voedselgewasse direk affekteer nie. In Suid Afrika word jaarliks ongeveer 6 miljoen ton SB geproduseer, waarvan die meeste by die suikermeulens verbrand word om stoom te genereer. Weens die huidige belangstelling in bio-brandstowwe en ondoeltreffende benutting van SB as energieproduk in die suikerindustrie moet alternatiewe energie-onginningsprosesse ondersoek word. Hierdie studie is op die termo-chemiese verwerking van SB deur middel van pirolise gefokus. Biomassa pirolise word gedefinieer as die termo-chemiese afbreking van organiese bio-materiaal in die afwesigheid van suurstof en ander reagense. Stadige Pirolise (SP), Vakuum Pirolise (VP), en Vinnige Pirolise word in hierdie tesis ondersoek. Die drie prosesse produseer veskillende hoeveelhede houtskool en bio-olie wat albei voordele bied vir die suikerindustrie. Houtskool kan as ‘n vaste energie-digte brandstof verbrand of vergas word, as bio-houtskoolkompos gebruik word, of kan verder tot geaktiveerde koolstof geprosesseer word. Hoë kwaliteit bio-olie kan verbrand of vergas word, kan as bron vir chemikalië gebruik word, en toon potensiaal om in die toekoms opgegradeer te kan word tot vervoerbrandstof kwaliteit. Vinnige pirolise is die mees moderne pirolise tegnologie en is op bio-olie produksie gefokus. Om die laasgenoemde proses te toets is ‘n 1 kg/h vinnige pirolise eenheid ontwerp, opgerig en in werking gestel. Die nuwe pirolise eenheid is getoets en vegelyk met twee verskillende vinnige pirolise eenhede by Forschungszentrum Karlsruhe (FZK) in Duitsland. Termo-Gravimetriese Analise (TGA) is gedoen om die ontvlugtigingskenmerke van SB te bestudeer. Eksperimentele werk is verrig om die kwaliteit van produkte van SP, VP, vinnige pirolise te vergelyk. Drie duidelike massaverlies fases van TGA is geïdentifiseer. Die eerste fase (25 – 110°C) is as gevolg van die verdamping van vog. Pirolitiese ontvlugtiging het begin by 230°C. Die finale fase (> 370°C) is met die kraking van swaar verbindings en die vorming van houtskool geassosieer. Die optimale afbrekingstemperatuur vir hemisellulose en sellulose is as 290°C en 345°C, respektiewelik, geïdentifiseer. Daar is gevind dat lignien stadig oor die twede en derde fases afgebreek word sonder ‘n duidelike optimale afbrekingstemperatuur. Die resultate is deur vorige navorsing op TGA van SB bevestig. SP en VP van bagasse is in dieselfde reaktor bestudeer, om ‘n akkurate vergelyking moontlik te maak. Beide prosesse was by lae verhittingstempo’s (20°C/min) ondersoek, wat gevolglik op houtskoolformasie gefokus is. SP het die hoogste houtskoolopbrengs, met die hoogste verbrandingsenergie, geproduseer. VP het hootskool met die hoogste BET oppervlakarea geproduseer, en die bio-olie was weens ‘n dramatiese afname in waterinhoud van beter gehalte. Die meganisme vir die vorming van ‘n poreuse struktuur word deur lae atmosferiese druk verbeter. Daar bestaan ‘n inverse verband tussen die kwantiteit en kwaliteit van die houtskool. Vinnige pirolise by die Universiteit van Stellenbosch het ‘n bio-olie opbrengs van 65 ± 3 massa% by ‘n vooraf vasgestelde optimale temperatuur van 500°C geproduseer. Die eienskappe van bio-olie wat deur die nuwe vinnige pirolise eenheid geproduseer is het goed ooreengestem met die bio-olie afkomstig van FZK se pirolise eenhede. Die houtskool eienskappe van die drie pirolise eenhede het enkele verskille getoon. By optimale toestande vir vinnige pirolise word daar 20 massa% meer bio-olie as by SP en VP geproduseer. Vinnige pirolise bio-olie het ‘n waterinhoud van 20 massa% en ‘n verbrandingswarmte van 18 ± 1 MJ/kg. Daar is gevind dat ten opsigte van droë SB die energie per enheidsvolume van bio-olie ongeveer 11 keer meer is. Vinnige pirolise is die mees doeltreffende proses vir die vervaardiging van ‘n produk wat meer as 60% van die oorspronklike biomassa energie bevat. Daar is gevind dat die optimale hoeveelhede van hoë kwaliteit bio-olie en hoë oppervlakarea houtskool doelafhanklik is.

Sugarcane is a major crop in many countries. It is the most abundant lignocellulosic material in tropical countries such as South Africa. It is one of the plants with the highest bioconversion efficiency. The sugarcane crop is able to efficiently fix solar energy, yielding some 55 tons of dry matter per hectare of land annually. After harvest, the crop produces sugar juice and bagasse. Sugarcane bagasse is a residue that results from the crushing of sugarcane in the sugar industry. It is a renewable feedstock that can be used for power generation and manufacturing cellulosic ethanol. As biomass, sugarcane bagasse holds promise as a fuel source since it can produce more than enough electricity and heat energy to supply the needs of a common sugar factory. However, in the sugarcane industry the bagasse is currently burnt inefficiently in boilers that provide the heating for the industry. This project seeks to investigate the possibility of gasifying sugarcane bagasse as an efficient conversion technology. The investigation is necessary because fuel properties govern the gasifier design and ultimately, the gasification efficiency. Proximate and ultimate analysis of sugarcane bagasse was conducted after which the results were used to conduct a computer simulation of the mass and energy balance during gasification. The kinetic investigation undertaken through the TGA and DTG analyses revealed the activation energy and pre – exponential factor which were obtained by the model – free Kissinger method of kinetic analysis and were found to be 181.51 kJ/mol and 3.1 × 103/min respectively. The heating value of sugarcane bagasse was also measured and found to be 17.8 MJ/kg, which was used in the calculation of the conversion efficiency of the gasification process. Fuel properties, including moisture content and gasifier operating parameters were varied in order to determine optimum gasifier operating conditions that results in maximum conversion efficiency. The highest conversion efficiency was achieved at low moisture content after computer simulation of the gasification process. Moisture content also affected the volume of CO and H2 as the former decreases with increasing moisture content while the latter increases with increasing moisture content, accelerating the water – gas reaction. Scanning electron microscope fitted to an Energy dispersive X – ray spectroscopy was also used in order to view the shape and size distribution as well as determine the elemental composition of sugarcane bagasse. The results obtained established that the fuel properties and gasification conditions affect the conversion efficiency. During computer simulation, it was established that smaller particle size resulted in higher conversion efficiency. The smaller throat diameter also resulted in higher conversion efficiency. The throat angle of 25° also resulted in higher conversion efficiency. The temperature of input air was also found to be one of the major determining factors in terms of conversion efficiency. The dissertation presents the proximate and ultimate analysis results as well as the kinetic analysis results. The SEM/EDX analysis as well as the computer simulation results of the gasification process is also presented. The major contribution of this project was on the investigation of the gasification characteristics of sugarcane bagasse and the utilization of these in the design of a laboratory scale sugarcane bagasse gasifier with enhanced conversion efficiency through computer simulation.

With rapidly increasing interest in a cleaner world environment, biomass com­bustion is becoming a very real alternative energy source to the more traditional coal-fired power stations. Sugar cane bagasse is one such material that is readily available and moreover, has been used as a fuel in the Australian sugar industry for well over thirty years. Today, the most widely utilised bagasse-fired furnace is the 'pneumatic spreader suspension fired furnace'. In this particular design, the solid bagasse particles are blown into the furnace by high velocity air jets, where the majority of the fuel is entrained vertically by a large flow of pre-heated air. This stream is termed 'combustion air' and enters the furnace via a grate spanning the entire furnace floor. Combustion of bagasse in these furnaces has its own special set of problems which appear to be due largely to the high moisture content of the fuel (45 - 55% as fired (wet basis)). Combustion instability in bagasse-fired furnaces is a key issue for operation but is presently not well understood. During periods of instability, there is a con­siderable dulling of the flame, the furnace pressure oscillates, large mounds of wet fuel accumulate on the grate and it becomes impossible to maintain the mill steam requirements. Dixon (1984) describes this as the 'single factor limiting the further development of bagasse suspension firing'. Since the early eighties, the majority of the research into this problem has been on a 'trial and error' basis with only lim­ited success. More recently an in-depth theoretical and computational investigation was undertaken into modelling of bagasse-furnaces (Luo, 1993; Luo and Stanmore, 1994). The work of Luo and Stanmore (1994) and the work of Dixon (1983,1984) provide the starting point for this current research.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references (leaves 13-15).
The economics of implementing bagasse-based charcoal manufacturing in Haiti was investigated. From these main inputs, three different manufacturing economic scenarios were modeled using a simple, dynamic excel spreadsheet. The first model reflects single family implementation, which reasonable found that a family would be able to make back their start up costs within a month of production. The second model examined sugarcane bagasse charcoal production as an entrepreneurial endeavor for a small community. The third model is similar to the second model, but reflects large-scale factory production. The potential of the second and third models primarily depend on the cost of raw materials and transportation. These models are easily adjusted to reflect market rates and can be generalized to address similar start-up economies.
by Lynn K. Kamimoto.
S.B.

Universidade Federal do CearÃ
The present work aimed at the production of lignosulfonate, based in the lignin extracted from sugarcane bagasse-cane for using in phenolic resins. The extraction of lignin was carried out using the acetosolv process, which was optimised with a central composite design 22 to evaluate the effects of reaction time and temperature on the extraction yield, weight-average (M ̅w) and number-average (M ̅n) molecular weights, relative content of total hydroxyl, phenolic hydroxyl and methoxyl groups. The lignins obtained under conditions that maximized the extraction yield and showed better structural and thermal characteristics were sulfonated to obtain the lignosulfonates. The structural and thermal characteristics of the lignins and lignosulfonates were determined by FT-IR, GPC, 1H-NMR and 13C-NMR, DSC and TGA. The results show that the best extraction yield (64.5%) was obtained with 95% (w/w) of acetic acid, the addition of 0.1% HCl, at a temperature of 187 ÂC and reaction time of 40 min. However, with the same concentration of acetic acid and reaction time of 15 min at 187 ÂC, the extraction yield decreased to 55.6% Â 4.5%, without significant reduction. Furthermore, the increase in temperature of 187 ÂC to 205 ÂC was not enough to cause a significant increase in the relative content of hydroxyls and reduction of the relative content of methoxyl. These results show that the most appropriate conditions for adequate extraction of lignin for application in resins are: 95% (w/w) of acetic acid, addition of 0.1% of HCl, temperature of 187 ÂC and reaction time of 15 min. The acetosolv lignins showed p-hidroxifenila units as major constituent, higher thermal stability and higher purity than the commercial Kraft lignin. The glass transition temperature of the Kraft lignins was lower than that of the acetosolv lignin. This is due to the hydrophilic character and the presence of carbohydrates in the Kraft lignin. The lignosulfonates obtained in this study showed structural characteristics suitable for application in phenolic resins, because they showed high reactivity due to the greater presence of p-hidroxifenila units as major constituent, low molecular weights (40234878 g/mol), greater stability and greater purity compared to commercial sodium lignosulfonate. Therefore, lignosulfonates obtained in this work are more suitable for use in phenolic resins than commercial sodium lignosulfonate used for comparison.
O presente trabalho teve por objetivo a produÃÃo de lignossulfonato, a partir da lignina extraÃda do bagaÃo da cana-de-aÃÃcar para aplicaÃÃo em resinas fenÃlicas. Foi realizada a otimizaÃÃo da extraÃÃo da lignina do bagaÃo de cana-de-aÃÃcar utilizando o processo acetosolv. Para tanto, empregou-se um delineamento composto central 22 para analisar os efeitos do tempo de reaÃÃo e da temperatura no rendimento de extraÃÃo, massa molar ponderal mÃdia, massa molar numÃrica mÃdia, e conteÃdo relativo de hidroxilas totais, hidroxilas fenÃlicas e metoxilas. As ligninas obtidas nas condiÃÃes que maximizaram o rendimento de extraÃÃo e que mostraram melhores caracterÃsticas estruturais e tÃrmicas foram sulfonadas para obtenÃÃo dos lignossulfonatos. As caracterÃsticas estruturais e tÃrmicas das ligninas e dos lignossulfonatos foram determinadas por FT-IR, GPC, RMN-1H e 13C, TGA e DSC. Os resultados mostram que o melhor rendimento de extraÃÃo (64,5 % 4,2%) foi obtido com 95% (m/m) de Ãcido acÃtico, adiÃÃo de 0,1% de HCl, a uma temperatura de 187 C e tempo de reaÃÃo de 40 min. No entanto, com a mesma concentraÃÃo de soluÃÃo de Ãcido acÃtico e com tempo de reaÃÃo de 15 min a 187ÂC, o rendimento de extraÃÃo diminuiu para 55,6%  4,5%, nÃo sendo significativa esta reduÃÃo. AlÃm disto, a elevaÃÃo da temperatura de 187ÂC para 205ÂC nÃo foi suficiente para causar um aumento significativo no conteÃdo relativo de hidroxilas e reduÃÃo do conteÃdo relativo de metoxila. Esses resultados mostram que as condiÃÃes mais adequadas para extraÃÃo da lignina a ser aplicada em resinas sÃo: 95% (m/m) de Ãcido acÃtico, adiÃÃo de 0,1% de HCl, temperatura de 187 C e tempo de reaÃÃo de 15 min. As ligninas acetosolv apresentaram unidades p-hidroxifenila como constituinte majoritÃrio, maior estabilidade tÃrmica e maior pureza em relaÃÃo à lignina Kraft comercial. A temperatura de transiÃÃo vÃtrea da lignina Kraft foi menor do que à das ligninas acetosolv, devido à sua caracterÃstica hidrofÃlica e à presenÃa de carboidratos na lignina Kraft. Os lignossulfonatos obtidos no presente trabalho apresentaram caracterÃsticas estruturais adequadas para aplicaÃÃo em resinas fenÃlicas, pois mostraram alta reatividade devido a maior presenÃa de unidades p-hidroxifenila como constituinte majoritÃrio, baixas massas molares (4023 a 4878 g/mol), maior estabilidade e uma maior pureza em relaÃÃo ao lignossulfonato de sÃdio comercial. Portanto, os lignossulfonatos obtidos no presente trabalho sÃo mais adequados para aplicaÃÃo em resinas fenÃlicas do que o lignossulfonato de sÃdio comercial utilizado no presente trabalho.

Sugarcane is considered as the most abundant plant based crop grown in the tropics and part of the temperate climates. Its by-product, sugarcane bagasse, constitutes 30% of the total production. In the past, it was considered as waste material but contemporaries through innovative research projects over the years have found uses for it. Among these projects is soil reinforcement, which provides an alternative application to industrial by-products and natural fibres as a way of reducing their environmental footprints and contributing to sustainable geotechnics. Although bagasse morphological composition contains structural elements ideal for reinforcement and composite materials, it has received little research as a standalone reinforcement material. Because of this, a direct shear test was therefore initiated to establish the usefulness of using sugarcane bagasse as a soil reinforcement material by comparing the extent of shear strength and stiffness response due to its inclusion to unreinforced soil. Three different types of bagasse, fibre, millrun and pith, were added to unreinforced soil in percentage by weight content of 0.3 - 1.7. The bagasse was added to Klipheuwel sand, Cape Flats sand and Kaolin Clay at both dry and moist conditions. In addition, durability studies involving 12 cycles of wetting and drying, and soaking for a period of 14 days were constituted.

This work was stimulated by the fact that supplies of fossil fuels are finite, while there are abundant renewable forms of energy waiting to be tapped. The current fossil fuels store is reviewed before identifying usable forms of renewable energy which could replace or supplement fossil fuels. Bagasse - a solid byproduct in sugarcane milling - is then described in detail as a typical lignocellulosic waste which forms part of a larger class of renewable energy sources called biomass. The chemical and physical characteristics, as well as world-wide regions of production of bagasse are described. The research work therefore concerned itself with investigating various physical methods of conserving renewable energy by improving on the extraction efficiency of such energy from bagasse. The equipment used for carrying out the research work is described in detail in chapter two. The methods employed in carrying out the investigations are similarly described in the same chapter, detailing every step in the investigations, including any precautions which had to be taken. The crude results from the investigations are analysed in detail in chapter three so that fuel combustion, combustion oxygen demand, heat and mass balances for the process are considered. An analysis of the boiler system - the main equipment in the investigations - is also carried out in chapter three so that temperatures, gas flow patterns, particle elutriations and size distributions of the fuel in the system are established. Conclusions of the investigations are then drawn from the analyses of chapter three. As a prelude to the conclusion of the work, an industrial biomass survey carried out in Tanzania is analysed to show that bagasse is not the only lignocellulosic which is produced industrially, and that reasonable financial savings can be obtained from these other lignocellulosics. The work concludes by describing a few areas of related research interest for further investigation.

In the Australian sugar industry, sugar cane is smashed into a straw like material by hammers before being squeezed between large rollers to extract the sugar juice. The straw like material is initially called prepared cane and then bagasse as it passes through successive roller milling units. The sugar cane materials are highly compressible, have high moisture content, are fibrous, and they resemble some peat soils in both appearance and mechanical behaviour. A promising avenue to improve the performance of milling units for increased throughput and juice extraction, and to reduce costs is by modelling of the crushing process. To achieve this, it is believed necessary that milling models should be able to reproduce measured bagasse behaviour. This investigation sought to measure the mechanical (compression, shear, and volume) behaviour of prepared cane and bagasse, to identify limitations in currently used material models, and to progress towards a material model that can predict bagasse behaviour adequately. Tests were carried out using a modified direct shear test equipment and procedure at most of the large range of pressures occurring in the crushing process. The investigation included an assessment of the performance of the direct shear test for measuring bagasse behaviour. The assessment was carried out using finite element modelling. It was shown that prepared cane and bagasse exhibited critical state behaviour similar to that of soils and the magnitudes of material parameters were determined. The measurements were used to identify desirable features for a bagasse material model. It was shown that currently used material models had major limitations for reproducing bagasse behaviour. A model from the soil mechanics literature was modified and shown to achieve improved reproduction while using magnitudes of material parameters that better reflected the measured values. Finally, a typical three roller mill pressure feeder configuration was modelled. The predictions and limitations were assessed by comparison to measured data from a sugar factory.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
O bagaço da cana-de-açúcar é uma biomassa vegetal que possui muito potencial de uso devido aos seus três elementos estruturais: celulose, hemicelulose e lignina. Para servir como matéria prima na produção de insumos, o bagaço da cana-de-açúcar precisa passar por um processo de pré-tratamento. Nesse estudo, duas metodologias para o processo de pré-tratamento do bagaço da cana-de-açúcar foram utilizadas: a deslignização via peróxido de hidrogênio (H2O2) e via dióxido de carbono supercrítico (ScCO2). Para o estudo utilizando H2O2, foram desenvolvidos modelos a partir de planejamento experimental, Algoritmos Genéticos (GA, do inglês Genetic Algorithms), Redes Neurais Artificiais (RNA) e Neuro-Fuzzy (ANFIS). As variáveis independentes foram temperatura (25 – 60 graus Celsius), concentração de H2O2 (2 – 15 por cento m/v) e pH (10 – 13), tendo como resposta os teores de lignina residual e oxidada no processo, através de análises de FT-IR e análise pelo método de Klason. Para o estudo utilizando ScCO2 foram construídos modelos a partir de RNA e ANFIS. As variáveis estudadas no processo foram: temperatura (35 – 100 graus Celsius), pressão (75- 300 bar) e teor de etanol na solução de co-solvente (0 – 100 graus Celsius). De modo geral, para os dois processos, os modelos desenvolvidos consideram as variáveis independentes como sendo neurônios na camada de entrada e as variáveis dependentes como sendo neurônios na camada de saída. Todos os modelos neurais e ANFIS desenvolvidos neste trabalho foram avaliados pelo coeficiente de correlação e índices de erro (SSE, MSE e RMSE), além do número de parâmetros. Os resultados mostraram que, dentre estas estratégias estudadas, os modelos neurais se mostraram mais satisfatórios para predição das respostas do pré-tratamento com H2O2, já que se encaixa nos índices de performance estipulados. O mesmo ocorreu no modelo neural para predição do teor de lignina residual no pré-tratamento com ScCO2. Para cada modelo polinomial e neural desenvolvido, foi realizada a investigação das superfícies de respostas e das curvas de contorno. Com esse recurso, foi possível a identificação dos melhores pontos operacionais para os processos, visando a minimização dos teores de lignina residual e oxidada na biomassa.
Sugarcane bagasse is a plant biomass that has a great potential for use due to its three structural elements: cellulose, hemicellulose and lignin. To serve as raw material in the production of other products, sugarcane bagasse needs to undergo a pre-treatment process. In this study, two methodologies for the sugarcane bagasse pretreatment process were used: delignification via hydrogen peroxide (H2O2) and via supercritical carbon dioxide (ScCO2). The models for study the process with H2O2 were developed from experimental planning, Genetic Algorithms (GA), Artificial Neural Networks (ANN) and Neuro-Fuzzy (ANFIS). The independent variables were: temperature (25- 60 degrees Celsius), H2O2 concentration (2 - 15 percent m/v) and pH (10-13). The residual and oxidized lignin contents in the process were evaluated from FT-IR and Klason method analysis. The models for study the process with ScCO2 were developed from RNA and ANFIS. The variables studied in the process were: temperature (35-100 degrees Celsius), pressure (75-300 bar) and ethanol content in the aqueous solution of co-solvent (0-100 percent). In general, for the two processes, the developed models consider the independent variables to be neurons in the input layer and the dependent variables to be neurons in the output layer. All the neural and ANFIS models developed in this study were evaluated by the correlation coefficient and error indexes (SSE, MSE and RMSE), as well as the number of parameters. From the stipulated indices of performance, among the results obtained by the different strategies, the neural models were the most satisfactory for the prediction of pretreatment responses with H2O2. The same occurred in the neural model for prediction of the residual lignin content in the pre-treatment with ScCO2. Response surfaces and the contour curves were investigated for each polynomial and neural model developed. With this resource, it was possible to identify the best operational points for the processes, pointing at minimizing the residual and oxidized lignin contents in the biomass.

In the Australian sugar industry, sugar cane is smashed into a straw like material by hammers before being squeezed between large rollers to extract the sugar juice. The straw like material is initially called prepared cane and then bagasse as it passes through successive roller milling units. The sugar cane materials are highly compressible, have high moisture content, are fibrous, and they resemble some peat soils in both appearance and mechanical behaviour. A promising avenue to improve the performance of milling units for increased throughput and juice extraction, and to reduce costs is by modelling of the crushing process. To achieve this, it is believed necessary that milling models should be able to reproduce measured bagasse behaviour. This investigation sought to measure the mechanical (compression, shear, and volume) behaviour of prepared cane and bagasse, to identify limitations in currently used material models, and to progress towards a material model that can predict bagasse behaviour adequately. Tests were carried out using a modified direct shear test equipment and procedure at most of the large range of pressures occurring in the crushing process. The investigation included an assessment of the performance of the direct shear test for measuring bagasse behaviour. The assessment was carried out using finite element modelling. It was shown that prepared cane and bagasse exhibited critical state behavior similar to that of soils and the magnitudes of material parameters were determined. The measurements were used to identify desirable features for a bagasse material model. It was shown that currently used material models had major limitations for reproducing bagasse behaviour. A model from the soil mechanics literature was modified and shown to achieve improved reproduction while using magnitudes of material parameters that better reflected the measured values. Finally, a typical three roller mill pressure feeder configuration was modelled. The predictions and limitations were assessed by comparison to measured data from a sugar factory.

Thesis (PhD)--Macquarie University, Division of Environmental and Life Sciences, Department of Chemistry, 2002.
Bibliography: leaves 234-240.
Introduction, theoretical descriptions of spontaneous combustion phenomena and aims of this thesis -- Laboratory measurements of the self-heating phenomenology of bagasse -- Field experiments investigating the self-heating behaviour of large scale stockpiles of low symmetry -- Self-heating and thermal ignition of calcium hypochlorite -- Experimental methods and procedures used for the critical ambient temperature of HCH -- Results of critical ambient temperature measurements upon single containers of hydrated high strength HCH -- Experiments on the interaction of self-heating drums -- Conclusions.
The hazard of spontaneous combustion is a problem that confronts any industry that transports or stores a reactive material. Bagasse is a reactive material that presents an expensive spontaneous combustion hazard for the sugar industry since this material is the principal fuel used at sugar mills. Calcium Hypochlorite is another such material presenting a significant industrial spontaneous combustion hazard for the transport and insurance industry as it has been linked to a number of expensive maritime conflagrations. The investigation of fundamental self-heating phenomenon is critical for the understanding, control and prevention of spontaneous ignition with these materials. -- By way of isothermal calorimetry techniques and fundamental thermal ignition measurements, this study has provided improved understanding into the oxidative self-heating phenomenology of bagasse and thermal ignition phenomenology of calcium hypochlorite. Both substances have been shown to possess unusual and previously unknown self-heating behaviour at temperatures below 100°C, with water being a principal component of each mechanism. -- The outcomes of this study have provided a platform which has enabled current mathematical models to predict large scale self-heating phenomena for industrially stored quantities of these materials.
Mode of access: World Wide Web.
240 leaves, bound ill

Sugarcane cultivation is a major source and sinks of greenhouse gas emissions (GHGs). In 2019, approximately 30.04 x 106 t of sugarcane was harvested from 364,428 ha of land. Of the total cane harvested, sugarcane bagasse (SB) and sugarcane trash (ST) accounted for 30.1% and 14.9%, respectively. Further, fossil fuel consumption in the transport of cane to mills was 29.15 ML and is equivalent to 221.5 Mt CO2-equivalent GHG emissions. Anaerobic digestion (AD) of sugar industry wastes for biomethane production and use as vehicle fuel (bioCNG) would reduce the fossil fuel consumption and the associated GHG emissions in cane transportation to mill. The study aims to optimize biogas production and upgrade the produced biogas to vehicle fuel. For that the study is divided into different objectives. To determine the substrate characteristic and suitable AD parameters viz biodegradability (Experiment I), particle size (Experiment II), acid/base thermal pretreatment (Experiment III), C:N ratio (Experiment IV), and trace nutrient supplementation (Experiment V), to generate the maximum methane yield from ST with respect to SB was designed as objective I. At first, chemical composition and methane yields of ST and SB were determined through bench-scale biochemical methane potential (BMP) tests (Experiment I). Buswell’s equation predicted a theoretical methane yield of 291.0 and 349.4 mL CH4 g-1VSadded for ST (C107.8H179.1O101.4N1S0.08) and SB (C86.7H134.3O64.9N1S0.07), respectively. The corresponding methane yields with Modified Dulong’s equation were 266.3 and 298.7 mL CH4 g-1VSadded, respectively. The calculated energy value was 14.1 MJ for ST and 12.6 MJ for SB. However, experimental methane yields obtained were 161.8 and 187.9 mL CH4 g-1VSadded for ST and SB, respectively. First-order kinetic model revealed that experimental data fitted well (R2 = 0.99) with the modelling data and the hydraulic rate constant (khyd) values of 0.04 and 0.06 day-1 were obtained for ST and SB, respectively. However, modified Gompertz model had a lag phase () of 2.1 and 1.7 day, for ST and SB, respectively indicating hydrolysis was the rate limiting step for the studied lignocellulosic feedstocks. Thus, the effect of mechanical (Experiment II)., thermal and chemical pretreatments (Experiment III) on chemical composition and methane yields of ST and SB were evaluated. The effect of particle size of <0.25, 0.25-0.50, 0.50-1 and 1-2 mm on chemical composition and methane yields were determined. Results showed that particle size reduction had a profound effect on methane yields, especially for SB than for ST. For ST, particle size of 1-2 mm showed an improvement in methane yields by 19.1% over control (161.8 mL CH4 g-1 VSadded). For SB, the increase in methane yields over control (189.7 mL CH4 g-1 VSadded) were by 23.6%, 20.3%, 18.1% and 6.4% respectively at particle sizes of 1-2, 0.5-1, 0.25-0.5, 0.13-0.25 mm, respectively. These results suggest that the optimal particle size for anaerobic digestion of ST and SB will be 1-2 mm for maximum methane yield. Further, mechanical pretreatment through milling did not solubilise hemi-cellulose and/or improve delignfication but improved the surface area of the holocellulose. Therefore, the effect of chemical catalysts (dilute NaOH, H2SO4, HNO3) with and without steam explosion on chemical composition and methane yields was evaluated (Experiment III). Pretreatment conditions used for the steam explosion were 130 °C for 5 minutes at acid/base concentration of 2.5% catalyst loading. Results showed that the studied pretreatments had a profound effect on chemical composition and methane yields of ST. On comparison to control, dilute H2SO4, followed by NaOH and HNO3 addition with steam explosion improved the methane yields of ST by 63.5%, 52.1% and 45.6%, respectively. Steam explosion alone also improved the methane yields of ST by 40% over control. Biomass composition analysis showed that dilute H2SO4, HNO3, NaOH and steam explosion alone had improved the glucan content by 13.7%, 11.7%, 9.3% and 3% respectively than control. Dilute H2SO4 pretreatment improved the glucan availability by 45.2% and hemicellulose (xylan and arabinan) solubilisation by 63.7%-66.9%. Lignin depolymerisation in pretreated ST was improved (16.7%) over untreated ST. In Experiment I, chemical composition of ST and SB showed that the studied substrates were deficit in trace elements and contained high carbon to nitrogen (C/N) ratio of 92.4and 146.5 respectively. Therefore, the effect of C/N ratios of 15:1, 20:1, 25:1, 30:1, 35:1 and 40:1 with urea addition on methane yields of ST and SB was investigated (Experiment IV). Results showed that methane yields improved by 13.6% and 11.3% for ST when the C/N ratio was at 20:1 and 25:1, respectively. The corresponding values for SB were 14.2% and 14.3% at 20:1 to 25:1 C/N ratio, respectively. Both these results indicate that the optimal C/N was 20-25:1 for AD of lignocellulosic residues such as ST and SB. On the other hand, the effect of trace nutrients nickel (Ni), cobalt (Co), molybdenum (Mo), manganese (Mn), copper (Cu) and zinc (Zn) on methane yields during AD of ST and SB (Experiment V) showed that trace elements supplementation influenced the methane yields and both substrates responded differently. With ST, methane yields of 68.1% and 68.7% increase over control were noticed with addition of Co and Mo, respectively. For SB, methane yields increased by 48.6%, 63.9% and 4.8% with Co, Mo and Mn dosing at 2, 3, 90 mg kg-1 respectively. All other TE addition resulted in lower methane yields than control or inhibited the biogas production at different stages of incubation. All the batch BMP tests were conducted in triplicates at inoculum to substrate (ISR) ratio of 2 in serum glass bottles with a working volume of 100 mL and incubated statically at 37 °C. All the results were analysed for variance using LSD and Dunnett-t test giving methane yield as dependent variable (p<0.05). Second objective was designed to study the effect of organic loading on process performance and methane yields in four lab-scale stainless reactors (10 L working volume) and operated at an initial organic loading rate (OLR) of 1.5 gVS L-1 d-1 with hydraulic retention times (HRT) of 35 days for 225 days. Reactors were fed with untreated ST (ST), untreated SB (SB), pretreated SB (TB) and pretreated ST (TT). Dilute H2SO4 followed by steam explosion (Experiment II) was used for pretreatment of ST and SB. OLR was increased in a stepwise manner from the initial rate of 1.5 to 2.5 and 3.5 gVS L-1 d-1. OLR was changed upon achieving steady-state condition and/or operating for 2 consecutive HRTs. Methane production rates and yields responded with increase in OLR from 1.5 to 2.5 gVS L-1 d-1. Mean methane yields of 138, 173, 248 and 252 ml g-1VSfed were obtained at an OLR 1.5 gVS L-1 d-1 in ST, SB, TT and TB reactors, respectively. Increase in OLR to 2.5 gVS L-1 d-1 showed decrease in methane yields. Mean methane yields obtained for TB, TT, SB and ST were 121, 148, 226, 236 ml g-1VSfed with a VS removal rate of 48.5, 51.4, 51.5 and 52.4%, respectively. Process parameters such as pH, total ammoniacal nitrogen (TAN) and total volatile fatty acids (TVFA) were shown to be stable and were 7.3-7.5, 0.36-0.54 g L-1 and 0.79-0.98 g L-1 respectively during operational OLR’s. Further increase in OLR from 2.5 to 3.5 gVS L-1 d-1 resulted in further decrease in methane yields and unstable AD process. At OLR 3.5 gVS L-1 d-1, methane yields were 119, 139, 189 and 199 ml g-1VSfed for substrates ST, SB, TT and TB respectively. TVFA accumulation was noticed (1.55-2.49 g L-1) , pH was 7.4-7.5 and lower methane concentration (50.5-51.9%). Residual methane production (RMP) test after each OLR indicated the process efficiency. At OLR 2.5 gVS L-1 d-1, TT and TB reactors had the lowest RMP (32.1% and 30.2% respectively) with relatively high VS removal compared with SB and ST reactors. These results indicate that steam explosion with dilute sulphuric acid improved the biodegradability and methane yields of ST and SB. The results obtained from the lab-scale reactors were used to design and optimise process performance and methane yields from pretreated sugarcane trash in pilot-scale reactors (date not presented). Third objective was designed to evaluate detailed biogas composition and to develop and optimise high pressure water scrubbing technology (HPWS). For that, the biogas composition, energy content, siloxanes and trace volatile organic compounds in biogas generated from lab-scale biogas reactors were determined and compared with the pilot-scale. Laboratory biogas samples were collected during the steady-state condition when the reactors were operated at an OLR of 2.5 gVS L-1 d-1. Results showed that biogas collected from ST, SB, TT and TB reactor had methane concentration of 52.3, 52.2, 52.7, 52.7 %, respectively. The corresponding lower calorific values (LCV) were 18.4, 18.1, 18.9 and 19.2 MJ m-3 respectively. The wobbe index values in the biogases were 18.3, 18.2, 18.7 and 19.0 MJ m-3, respectively. Volatile organic compounds were noticed in the biogas samples. Organic silicon compounds (siloxanes) were in the range of 0-0.4 mg m-3. The reduced sulphur compounds and benzene and toluene content in the biogases were in the range of 0.7-1.3 mg m-3 and 0.2-0.7 mg m-3, respectively. Among the studied siloxanes, the proportion of cyclic siloxane (D3:D4:D5) viz., hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) were noticed. The ratio of D3:D4:D5 in biogases produced from lab-reactors were 68.5:5.7: 22.4 for ST, 33.9:4.9: 60.1 for SB, 25:8.6:69.3 for TT and 14.8:3.7:81.8 for TB. Trimethylsilanol, linear siloxanes and decamethylcyclohexasiloxane (D6) content in the biogases were below the detection limits. Volatile organic compounds, reduced sulphur compounds and siloxanes cause environmental impact and affect biomethane quality for vehicle fuel use. Biogas composition from pilot-scale biogas reactors (1.2 m3 reactor with 0.8 m3 working volume) fed with steam exploded ST at an OLR of 1.5 kgVS m-3 d-1 and HRT of 35 d was analysed to optimise the process parameters to achieve the desired biomethane quality and evaluate the energy requirements of pilot-scale biogas upgrading unit (10 m3 h-1) for biogas upgrading and bottling. Results showed that the biogas had 54.1% CH4 and 39.7% CO2 and the produced biogas was upgraded to 96.7% biomethane purity by using high pressure water scrubbing process. Experimental data from the biogas upgrading process was used to optimise biogas upgrading by using Aspen Plus software. The influence of process parameters such as absorber column pressure, water to gas flow rate, temperature on biomethane purity and percentage of H2S and CO2 removal were evaluated. Experimental results showed that at liquid flow rate of 3 m3/hr, fluid temperature of 20°C, at absorption column pressure of 8 bar with 4 m random packing material with redistributor at 2 m with 25 mm plastic pall ring packing material; biogas can be upgraded to biomethane of 96.8% CH4, 2.9% CO2, < 1 ppm H2S. These model results were validated with software simulation.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text

Lignocellulosic feedstocks are the most abundant biomass on earth with a high potential of producing fuels and the shortage of fossil fuels and environmental pollution resulting from burning fossil fuels have boosted interest in lignocellulose in the past few decades. Hydrothermal Liquefaction (HTL) is a process where the biomass is heated at a high temperature and high pressure to produce bio-oil. Sweet sorghum bagasse has been used in our research for this process because of its abundance in the world and in the United States. HTL of sweet sorghum bagasse was carried out under varying conditions of temperature, catalyst concentration and reaction time. This study aimed to find out the optimum condition that can lead to maximum yield of bio-oil. By testing each variable at three levels, the Box Behnken design necessitated a total of 17 runs. Among these conditions, the highest bio-oil yield of 45.28% was observed at 300oC with K2CO3 at 1M and a residence time of 60 minutes. The obtained bio-oil yields under different operating conditions could be fitted well by a cubic model. This model predicted that a maximal bio-oil yield of 57% could be achieved if the HTL is conducted at 320oC with K2CO3 at 1M and a reaction time of 60 minutes. To confirm this model, HTL performed using the optimal condition led to a bio-oil yield of 52.215%. Under the same optimal condition, two more runs were carried out without the use of K2CO3 as a catalyst. The average bio-oil yield was 7.517%, which was much lower than those with the catalyst. Therefore, the presence of K2CO3 increased yield of bio-oil significantly. The CHNS/O analysis was conducted for selected bio-oil samples. The results indicated that bio-oil samples derived from HTL with K2CO3 had a high content of carbon and a very low content of sulfur and nitrogen. The oxygen content, however, was quite high. Thus, further upgrading the HTL bio-oil is needed to improve its heat content and fuel quality.

Over the last decade, Ionic Liquids (ILs) have been used for the dissolution and derivatization of isolated cellulose. This ability of ILs is now sought for their application in the selective dissolution of cellulose from lignocellulosic biomass, for the manufacture of cellulosic ethanol. However, there are significant knowledge gaps in the understanding of the chemistry of the interaction of biomass and ILs. While imidazolium ILs have been used successfully to dissolve both isolated crystalline cellulose and components of lignocellulosic biomass, phosphonium ILs have not been sufficiently explored for the use in dissolution of lignocellulosic biomass. This thesis reports on the study of the chemistry of sugarcane bagasse with phosphonium ILs. Qualitative and quantitative measurements of biomass components dissolved in the phosphonium ionic liquids (ILs), trihexyltetradecylphosphonium chloride ([P66614]Cl) and tributylmethylphosphonium methylsulphate ([P4441]MeSO4) are obtained using attenuated total reflectance-Fourier Transform Infra Red (FTIR). Absorption bands related to cellulose, hemicelluloses and lignin dissolution monitored in situ in biomass-IL mixtures indicate lignin dissolution in both ILs and some holocellulose dissolution in the hydrophilic [P4441]MeSO4. The kinetics of lignin dissolution reported here indicate that while dissolution in the hydrophobic IL [P66614]Cl appears to follow an accepted mechanism of acid catalysed β-aryl ether cleavage, dissolution in the hydrophilic IL [P4441]MeSO4 does not appear to follow this mechanism and may not be followed by condensation reactions (initiated by reactive ketones). The quantitative measurement of lignin dissolution in phosphonium ILs based on absorbance at 1510 cm-1 has demonstrated utility and greater precision than the conventional Klason lignin method. The cleavage of lignin β-aryl ether bonds in sugarcane bagasse by the ionic liquid [P66614]Cl, in the presence of catalytic amounts of mineral acid. (ca. 0.4 %). The delignification process of bagasse is studied over a range of temperatures (120 °C to 150 °C) by monitoring the production of β-ketones (indicative of cleavage of β-aryl ethers) using FTIR spectroscopy and by compositional analysis of the undissolved fractions. Maximum delignification is obtained at 150 °C, with 52 % of lignin removed from the original lignin content of bagasse. No delignification is observed in the absence of acid which suggests that the reaction is acid catalysed with the IL solubilising the lignin fragments. The rate of delignification was significantly higher at 150 °C, suggesting that crossing the glass transition temperature of lignin effects greater freedom of rotation about the propanoid carbon-carbon bonds and leads to increased cleavage of β-aryl ethers. An attempt has been made to propose a probable mechanism of delignifcation of bagasse with the phosphonuim IL. All polymeric components of bagasse, a lignocellulosic biomass, dissolve in the hydrophilic ionic liquid (IL) tributylmethylphosphonium methylsulfate ([P4441]MeSO4) with and without a catalytic amount of acid (H2SO4, ca. 0.4 %). The presence of acid significantly increases the extent of dissolution of bagasse in [P4441]MeSO4 (by ca. 2.5 times under conditions used here). The dissolved fractions can be partially recovered by the addition of an antisolvent (water) and are significantly enriched in lignin. Unlike acid catalysed dissolution in the hydrophobic IL tetradecyltrihexylphosphonium chloride there is little evidence of cleavage of β-aryl ether bonds of lignin dissolving in [P4441]MeSO4 (with and without acid), but this mechanism may play some role in the acid catalysed dissolution. The XRD of the undissolved fractions suggests that the IL may selectively dissolve the amorphous cellulose component, leaving behind crystalline material.

Dilute acid pretreatment is a process that is used to enhance ethanol yields in biofuel manufacturing by removing hemicelluloses from plant biomass. This thesis presents a new mathematical model of dilute acid pretreatment that can be used to predict hemicellulose yield profiles at the laboratory scale and inform further investigations at the industrial reactor scale. This work provides a framework for determining the optimal reaction conditions for acid pretreatment and thus has the potential to reduce the cost of commercial bioethanol production from 2nd generation lignocellulosic biomass feedstocks.

This project modelled a thermal liquefaction industrial facility for biofuel production from sugarcane bagasse using the process modelling software ASPEN Plus. Techno-economic models of liquefaction, pyrolysis and gasification processes were completed to assess the comparative feasibility of these thermochemical biofuel production processes. Model liquefaction biocrudes, were developed in ASPEN Plus using simulated distillation data and this method's utility in modelling biocrudes was validated.

The thesis investigated biorefining of sugarcane bagasse into value-added products. A glycerol-based fractionation method was developed at laboratory and pilot scales to convert sugarcane bagasse into fermentable sugar and high-quality lignin. The fermentable sugar was used for microbial oil production with applications in biofuel, biochemical, food and feed industries. The generated lignin had physico-chemical properties suitable for biochemical and polymer production. The thesis proposes methods to generate new revenue streams for Australian sugarcane industry.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.
Includes bibliographical references (leaves 33-34).
In Haiti, wood and wood charcoal are common fuels for cooking. This practice has contributed to deforestation, leading to erosion and fatal floods. The availability of charcoal made from a different source other than wood, such as agricultural waste, might provide Haitians with an alternative, more sustainable fuel, which in turn may reduce fuel prices. MIT students have developed various methods for producing charcoal out of simple inexpensive devices. In a current manufacturing process, carbonized bagasse is crushed to a powder, then mixed and agglomerated with yucca binder into balls. A novel method may reduce operator exposure and inhalation of charcoal fines by keeping primary manufacturing phases in the oil drum and reducing the operational steps of transferring the material from one location to another. The goal of this thesis was to understand, test, and optimize the parameters of this novel crushing and agglomeration process. The final prototype was found to effectively crushing charcoal and mix charcoal with binder to some extent, while being an inexpensive alternative to reduce overall charcoal exposure. However, the mixing and agglomeration was not sufficiently uniform and further designs should be considered to increase uniformity of mixing of binder and charcoal.
by Victoria Y. Fan.
S.B.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, June 2005.
"May 2005."
Includes bibliographical references (leaf 27).
Haiti is the poorest country in the Western hemisphere and is in need of cheap cooking fuel source. Currently, lump charcoal, the cooking fuel of Haiti, is made by carbonizing trees in ditches before selling the charcoal at market. However, Haiti is now 98% deforested and must find a way to prepare their food that does not destroy their land. The idea for this new fuel comes from compressed and extruded carbonized bagasse, which was produced using an extruder developed in a senior product development class at MIT. Using this bagasse fuel, experiments were conducted to compare the combustion characteristics of the bagasse charcoals with wood charcoal. Unfortunately, the heat released by the bagasse charcoal did not compare favorably with that of the wood charcoal, failing to raise 1 L of water to boiling while the wood charcoal raised the water to boiling for 25 minutes. Since the bagasse charcoal performed similarly to Kingsford brand charcoal, the emissions released were compared between these two fuels. Based on their averages, the bagasse charcoal emitted 1.4 times more CO, 1.6 times more SO₂ and 2.3 times more particulates but only 17% of the NOx emitted by Kingsford.
by Andrés Ramírez.
S.B.

Torrefaction is a thermal pre-treatment process used to enhance the properties of biomass, including calorific value, hydrophobicity, and grindability, which makes it economically viable as fuel. Bagasse has a strong potential as a fuel when torrefied and can be used in many commercial applications. This research primarily focuses on the evaluation of bagasse as a potential feedstock to produce solid fuel comparable to coal using torrefaction and investigation of torrefaction process parameters.

Bagasse was torrefied at five different temperatures, 250°C, 270°C, 290°C, 310°C, and 330°C, for 1 hour to investigate the effect of temperature on degree of torrefaction. It was noticed that an increase in temperature improved the degree of torrefaction. This enhanced degree of torrefaction improved the properties of bagasse by reducing the hydrogen and oxygen contents, thereby increasing the percentage of carbon, which resulted in an increase of higher heating value. Decrease in moisture content was observed with temperature. The permanent gases obtained from the torrefaction mainly had carbon monoxide and carbon dioxide along with traces of hydrogen and methane. With temperature increase in the energy of permanent gases was noticed, and most of the energy was obtained from carbon monoxide. Condensable volatiles were also observed to increase with temperature.

The effect of residence time was studied by conducting the experiments with residence times 10, 30, and 60 minutes at 330°C. Residence time had a similar effect as that of the temperature enhancing the degree of torrefaction, thereby the fuel properties of bagasse.

Influence of carrier gas on the torrefaction was studied with different gases at 290°C with 1-hour residence time. The carrier gases used were nitrogen, carbon dioxide, and nitrogen in 80:20 ratio by volume, steam, synthesized syngas (46.978% N₂, 17.99% CO₂, 15.04% H₂, 14.99% CO, and 5.002% CH₄), and hydrogen and nitrogen in the ratios of 5:95 and 30:70. When carbon dioxide was used, bagasse had a better degree of torrefaction than that in the presence of nitrogen. It was noticed that steam, syngas, and hydrogen had a better influence on bagasse, enhancing its degree of torrefaction, than carbon dioxide and nitrogen.

The utilization of lignocellulosic residues to produce renewable energy is an interesting alternative to meet the increasing demand of fuels while at the same time reducing greenhouse gas emissions and climate change. Sweet sorghum bagasse is a lignocellulosic residue composed mainly of cellulose, hemicellulose, and lignin; and it is a promising substrate for ethanol production because its complex carbohydrates may be hydrolyzed and converted into simple sugars, and then fermented into ethanol. However, the utilization of lignocellulosic residues is difficult and inefficient. Lignocellulose is a very stable and compact complex structure, which is linked by β-1,4 and β-1,3 glycosidic bonds. Furthermore, the crystalline and amorphous features of cellulose fibers and the presence of hemicellulose and lignin make the conversion of lignocellulose into fermentable sugars currently impractical at commercial scale. The bioconversion of lignocellulose in nature is performed by microorganisms such as fungi and bacteria, which produce enzymes that are able to degrade lignocellulose. The present study evaluated the bioconversion of lignocellulosic residues of sweet sorghum into simple sugars using filamentous fungi directly in the hydrolysis of the substrate, without prior isolation of the enzymes. The fungus Neurospora crassa and some wild fungi (that grew naturally on sweet sorghum bagasse) were used in this investigation. The effect of the fungi on substrate degradation and the sugars released after hydrolysis were evaluated, and then compared with standard hydrolysis performed by commercial enzymes (isolated cellulases). In addition, different combinations of fungi and enzymes were used to determine the best approach. The main goal was to verify if the fungi were able to attack and break down the lignocellulose structure directly and at a reasonable rate, rather than by the current method utilizing isolated enzymes. The main finding of this study was that the fungi (N. crassa and wild fungi) were able to degrade sweet sorghum bagasse directly; however, in all of the cases, the hydrolysis process was not efficient because the hydrolysis rate was much lower than the enzymatic hydrolysis rate. Hydrolysis using a combination of fungus and commercial enzymes was a good approach, but still not efficient enough for practical use. The best results of combined hydrolysis were obtained when the substrate was under the fungus attack for three days and then, commercial enzymes with low enzymatic activity (7 FPU/g and 25 CBU/g) were added to the solution. These enzymes represent 10% of the current enzymatic activity recommended per gram of substrate. This process reached reasonable levels of sugars (close to 85% of sugars yield obtained by enzymatic hydrolysis); however, the conversion rate was still slower, making the process impractical and more expensive since it took twice the amount of time as commercial enzymes. Furthermore, the wild fungi able to degrade cellulose were isolated, screened, and identified. Two of them belong to the genus Aspergillus, one to the genus Acremonium, and one to the genus Rhizopus. Small concentration of spores-0.5mL- (see Table 4, CHAPTER III- for specific number of spores per mL) did not show any sugar released during hydrolysis of sweet sorghum bagasse. However, when the concentration of spores was increased (to 5mL and 10mL of solution), citric acid production was detected. This finding indicates that those wild fungi were able to degrade lignocellulose, even though no simple sugars were measured, citric acid production is an indicator of fungi growing and utilization of lignocellulose as nutrient. It is assumed that the fungi consume the sugars at the same time they are released, thus they are not detected. The maximum concentration of citric acid (~14.50 mg/mL) was achieved between days 8-11 of hydrolysis. On the other hand, before using lignocellulose, the substrate needed to be pretreated in order to facilitate its decomposition and subsequent hydrolysis. Sweet sorghum bagasse was washed three times to remove any soluble sugars remaining after the juice was extracted from the stalks. Then, another finding of this study was that the first wash solution could be used for ethanol production since the amount of sugars present in it was close to 13°Brix. The ethanol yield after 48 hours of fermentation was in average 6.82mg/mL, which is close to the theoretical ethanol yield. The other two washes were too dilute for commercial ethanol production. In terms of pretreatments, the best one to break down sweet sorghum bagasse was 2% (w/v) NaOH. This pretreatment shows the highest amounts of glucose and xylose released after hydrolysis. Unwashed and untreated bagasse (raw bagasse) did not show any sugar released. In terms of ethanol, 74.50% of the theoretical yield was reached by enzymatic hydrolysis, while 1.10% was reached by hydrolysis using the fungus N. crassa. Finally, it is important to remark that further investigation is needed to improve the direct conversion of lignocellulose into fermentable sugars by fungal enzymes. This approach is a promising technology that needs to be developed and improved to make it efficient and feasible at commercial scale.

This is an experimental study into the permeability and compressibility properties of bagasse pulp pads. Three experimental rigs were custom-built for this project. The experimental work is complemented by modelling work. Both the steady-state and dynamic behaviour of pulp pads are evaluated in the experimental and modelling components of this project. Bagasse, the fibrous residue that remains after sugar is extracted from sugarcane, is normally burnt in Australia to generate steam and electricity for the sugar factory. A study into bagasse pulp was motivated by the possibility of making highly value-added pulp products from bagasse for the financial benefit of sugarcane millers and growers. The bagasse pulp and paper industry is a multibillion dollar industry (1). Bagasse pulp could replace eucalypt pulp which is more widely used in the local production of paper products. An opportunity exists for replacing the large quantity of mainly generic paper products imported to Australia. This includes 949,000 tonnes of generic photocopier papers (2). The use of bagasse pulp for paper manufacture is the main application area of interest for this study. Bagasse contains a large quantity of short parenchyma cells called ‘pith’. Around 30% of the shortest fibres are removed from bagasse prior to pulping. Despite the ‘depithing’ operations in conventional bagasse pulp mills, a large amount of pith remains in the pulp. Amongst Australian paper producers there is a perception that the high quantity of short fibres in bagasse pulp leads to poor filtration behaviour at the wet-end of a paper machine. Bagasse pulp’s poor filtration behaviour reduces paper production rates and consequently revenue when compared to paper production using locally made eucalypt pulp. Pulp filtration can be characterised by two interacting factors; permeability and compressibility. Surprisingly, there has previously been very little rigorous investigation into neither bagasse pulp permeability nor compressibility. Only freeness testing of bagasse pulp has been published in the open literature. As a result, this study has focussed on a detailed investigation of the filtration properties of bagasse pulp pads. As part of this investigation, this study investigated three options for improving the permeability and compressibility properties of Australian bagasse pulp pads. Two options for further pre-treating depithed bagasse prior to pulping were considered. Firstly, bagasse was fractionated based on size. Two bagasse fractions were produced, ‘coarse’ and ‘medium’ bagasse fractions. Secondly, bagasse was collected after being processed on two types of juice extraction technology, i.e. from a sugar mill and from a sugar diffuser. Finally one method of post-treating the bagasse pulp was investigated. The effects of chemical additives, which are known to improve freeness, were also assessed for their effect on pulp pad permeability and compressibility. Pre-treated Australian bagasse pulp samples were compared with several benchmark pulp samples. A sample of commonly used kraft Eucalyptus globulus pulp was obtained. A sample of depithed Argentinean bagasse, which is used for commercial paper production, was also obtained. A sample of Australian bagasse which was depithed as per typical factory operations was also produced for benchmarking purposes. The steady-state pulp pad permeability and compressibility parameters were determined experimentally using two purpose-built experimental rigs. In reality, steady-state conditions do not exist on a paper machine. The permeability changes as the sheet compresses over time. Hence, a dynamic model was developed which uses the experimentally determined steady-state permeability and compressibility parameters as inputs. The filtration model was developed with a view to designing pulp processing equipment that is suitable specifically for bagasse pulp. The predicted results of the dynamic model were compared to experimental data. The effectiveness of a polymeric and microparticle chemical additives for improving the retention of short fibres and increasing the drainage rate of a bagasse pulp slurry was determined in a third purpose-built rig; a modified Dynamic Drainage Jar (DDJ). These chemical additives were then used in the making of a pulp pad, and their effect on the steady-state and dynamic permeability and compressibility of bagasse pulp pads was determined. The most important finding from this investigation was that Australian bagasse pulp was produced with higher permeability than eucalypt pulp, despite a higher overall content of short fibres. It is thought this research outcome could enable Australian paper producers to switch from eucalypt pulp to bagasse pulp without sacrificing paper machine productivity. It is thought that two factors contributed to the high permeability of the bagasse pulp pad. Firstly, thicker cell walls of the bagasse pulp fibres resulted in high fibre stiffness. Secondly, the bagasse pulp had a large proportion of fibres longer than 1.3 mm. These attributes helped to reinforce the pulp pad matrix. The steady-state permeability and compressibility parameters for the eucalypt pulp were consistent with those found by previous workers. It was also found that Australian pulp derived from the ‘coarse’ bagasse fraction had higher steady-state permeability than the ‘medium’ fraction. However, there was no difference between bagasse pulp originating from a diffuser or a mill. The bagasse pre-treatment options investigated in this study were not found to affect the steady-state compressibility parameters of a pulp pad. The dynamic filtration model was found to give predictions that were in good agreement with experimental data for pads made from samples of pretreated bagasse pulp, provided at least some pith was removed prior to pulping. Applying vacuum to a pulp slurry in the modified DDJ dramatically reduced the drainage time. At any level of vacuum, bagasse pulp benefitted from chemical additives as quantified by reduced drainage time and increased retention of short fibres. Using the modified DDJ, it was observed that under specific conditions, a benchmark depithed bagasse pulp drained more rapidly than the ‘coarse’ bagasse pulp. In steady-state permeability and compressibility experiments, the addition of chemical additives improved the pad permeability and compressibility of a benchmark bagasse pulp with a high quantity of short fibres. Importantly, this effect was not observed for the ‘coarse’ bagasse pulp. However, dynamic filtration experiments showed that there was also a small observable improvement in filtration for the ‘medium’ bagasse pulp. The mechanism of bagasse pulp pad consolidation appears to be by fibre realignment. Chemical additives assist to lubricate the consolidation process. This study was complemented by pulp physical and chemical property testing and a microscopy study. In addition to its high pulp pad permeability, ‘coarse’ bagasse pulp often (but not always) had superior physical properties than a benchmark depithed bagasse pulp.

This is an experimental study into the permeability and compressibility properties of bagasse pulp pads. Three experimental rigs were custom-built for this project. The experimental work is complemented by modelling work. Both the steady-state and dynamic behaviour of pulp pads are evaluated in the experimental and modelling components of this project. Bagasse, the fibrous residue that remains after sugar is extracted from sugarcane, is normally burnt in Australia to generate steam and electricity for the sugar factory. A study into bagasse pulp was motivated by the possibility of making highly value-added pulp products from bagasse for the financial benefit of sugarcane millers and growers. The bagasse pulp and paper industry is a multibillion dollar industry (1). Bagasse pulp could replace eucalypt pulp which is more widely used in the local production of paper products. An opportunity exists for replacing the large quantity of mainly generic paper products imported to Australia. This includes 949,000 tonnes of generic photocopier papers (2). The use of bagasse pulp for paper manufacture is the main application area of interest for this study. Bagasse contains a large quantity of short parenchyma cells called ‘pith’. Around 30% of the shortest fibres are removed from bagasse prior to pulping. Despite the ‘depithing’ operations in conventional bagasse pulp mills, a large amount of pith remains in the pulp. Amongst Australian paper producers there is a perception that the high quantity of short fibres in bagasse pulp leads to poor filtration behaviour at the wet-end of a paper machine. Bagasse pulp’s poor filtration behaviour reduces paper production rates and consequently revenue when compared to paper production using locally made eucalypt pulp. Pulp filtration can be characterised by two interacting factors; permeability and compressibility. Surprisingly, there has previously been very little rigorous investigation into neither bagasse pulp permeability nor compressibility. Only freeness testing of bagasse pulp has been published in the open literature. As a result, this study has focussed on a detailed investigation of the filtration properties of bagasse pulp pads. As part of this investigation, this study investigated three options for improving the permeability and compressibility properties of Australian bagasse pulp pads. Two options for further pre-treating depithed bagasse prior to pulping were considered. Firstly, bagasse was fractionated based on size. Two bagasse fractions were produced, ‘coarse’ and ‘medium’ bagasse fractions. Secondly, bagasse was collected after being processed on two types of juice extraction technology, i.e. from a sugar mill and from a sugar diffuser. Finally one method of post-treating the bagasse pulp was investigated. The effects of chemical additives, which are known to improve freeness, were also assessed for their effect on pulp pad permeability and compressibility. Pre-treated Australian bagasse pulp samples were compared with several benchmark pulp samples. A sample of commonly used kraft Eucalyptus globulus pulp was obtained. A sample of depithed Argentinean bagasse, which is used for commercial paper production, was also obtained. A sample of Australian bagasse which was depithed as per typical factory operations was also produced for benchmarking purposes. The steady-state pulp pad permeability and compressibility parameters were determined experimentally using two purpose-built experimental rigs. In reality, steady-state conditions do not exist on a paper machine. The permeability changes as the sheet compresses over time. Hence, a dynamic model was developed which uses the experimentally determined steady-state permeability and compressibility parameters as inputs. The filtration model was developed with a view to designing pulp processing equipment that is suitable specifically for bagasse pulp. The predicted results of the dynamic model were compared to experimental data. The effectiveness of a polymeric and microparticle chemical additives for improving the retention of short fibres and increasing the drainage rate of a bagasse pulp slurry was determined in a third purpose-built rig; a modified Dynamic Drainage Jar (DDJ). These chemical additives were then used in the making of a pulp pad, and their effect on the steady-state and dynamic permeability and compressibility of bagasse pulp pads was determined. The most important finding from this investigation was that Australian bagasse pulp was produced with higher permeability than eucalypt pulp, despite a higher overall content of short fibres. It is thought this research outcome could enable Australian paper producers to switch from eucalypt pulp to bagasse pulp without sacrificing paper machine productivity. It is thought that two factors contributed to the high permeability of the bagasse pulp pad. Firstly, thicker cell walls of the bagasse pulp fibres resulted in high fibre stiffness. Secondly, the bagasse pulp had a large proportion of fibres longer than 1.3 mm. These attributes helped to reinforce the pulp pad matrix. The steady-state permeability and compressibility parameters for the eucalypt pulp were consistent with those found by previous workers. It was also found that Australian pulp derived from the ‘coarse’ bagasse fraction had higher steady-state permeability than the ‘medium’ fraction. However, there was no difference between bagasse pulp originating from a diffuser or a mill. The bagasse pre-treatment options investigated in this study were not found to affect the steady-state compressibility parameters of a pulp pad. The dynamic filtration model was found to give predictions that were in good agreement with experimental data for pads made from samples of pretreated bagasse pulp, provided at least some pith was removed prior to pulping. Applying vacuum to a pulp slurry in the modified DDJ dramatically reduced the drainage time. At any level of vacuum, bagasse pulp benefitted from chemical additives as quantified by reduced drainage time and increased retention of short fibres. Using the modified DDJ, it was observed that under specific conditions, a benchmark depithed bagasse pulp drained more rapidly than the ‘coarse’ bagasse pulp. In steady-state permeability and compressibility experiments, the addition of chemical additives improved the pad permeability and compressibility of a benchmark bagasse pulp with a high quantity of short fibres. Importantly, this effect was not observed for the ‘coarse’ bagasse pulp. However, dynamic filtration experiments showed that there was also a small observable improvement in filtration for the ‘medium’ bagasse pulp. The mechanism of bagasse pulp pad consolidation appears to be by fibre realignment. Chemical additives assist to lubricate the consolidation process. This study was complemented by pulp physical and chemical property testing and a microscopy study. In addition to its high pulp pad permeability, ‘coarse’ bagasse pulp often (but not always) had superior physical properties than a benchmark depithed bagasse pulp.

付記する学位プログラム名: 京都大学大学院思修館
京都大学
新制・課程博士
博士(総合学術)
甲第23347号
総総博第20号
京都大学大学院総合生存学館総合生存学専攻
(主査)教授 山敷 庸亮, 教授 山本 貴士, 教授 寶 馨, 教授 齋藤 敬
学位規則第4条第1項該当
Doctor of Philosophy
Kyoto University
DFAM

The growing demand for energy in the world, the implications of climate change, the increasing damages to our environment and the diminishing fossil fuel reserves have created the appropriate conditions for renewable energy development. Biofuels such as bioethanol can be produced by breaking down the lignocellulosic structure of plant materials to release fermentable sugars. Sweet sorghum bagasse has been shown to be an important lignocellulosic crop residue and is potentially a significant feedstock for bioethanol production. The aim of this study was to investigate suitable microwave assisted pretreatment conditions of sweet sorghum bagasse for bioethanol production. A chemical pretreatment process of sweet sorghum bagasse, using different concentrations (1 to 7 wt%) of sulphuric acid (H2SO4) and calcium hydroxide (Ca (OH)2) was applied to break up the lignocellulosic matrix of sweet sorghum bagasse. The pretreated broth, which contained pentose and hexose sugars, was fermented using a combination of Zymomonas mobilis ATCC31821 and Saccharomyces cerevisiae to produce bioethanol at pH 4.8 and 32oC for 24 hours. The highest reducing sugar yield of 0.82 g/g substrate was obtained with microwave irradiation at 180 W for 20 minutes in a 5 wt% sulphuric acid solution. The highest ethanol yield obtained was 0.5 g/g from 5 wt% H2SO4 pretreated bagasse at 180 W using a 10:5% v/v of Saccharomyces cerevisiae to Zymomonas mobilis ratio, whereas for 3 wt% Ca (OH)2 microwave pretreatment, a sugar yield of 0.27 g/g substrate was obtained at 300 W for 10 minutes. Thereafter, an ethanol yield of 0.13 g/g substrate was obtained after 24 hours of fermentation when using a 10:5% v/v of Saccharomyces cerevisiae to Zymomonas mobilis ratio. The effect of microwave pretreatment on the bagasse was evaluated using Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The reducing sugars formed were quantified using High Performance Liquid Chromatography (HPLC). The results showed that microwave pretreatment using 5 wt% H2SO4 is a very effective pretreatment that can be used to obtain sugars from sweet sorghum bagasse. The analytic results also showed physical and functional group changes after microwave pretreatment. This confirms that microwave irradiation is very effective in terms of breaking up the lignocellulose structure and improving fermentable sugar yield for fermentation. Bioethanol yields obtained from microwave pretreatment using different solvents also show that Saccharomyces cerevisiae and Zymomonas mobilis ATCC31821 is a good combination for producing ethanol from sweet sorghum bagasse. Sweet sorghum bagasse is clearly a very effective and cheap biomass that can be used to produce bioethanol, since very high yields of fermentable sugars were obtained from the feedstock.
Thesis (MSc (Engineering Sciences in Chemical Engineering))--North-West University, Potchefstroom Campus, 2013.

New technologies, such as an efficient vapor-compression evaporator, a stationary lime kiln (SLK), and the MixAlco process, compelled us to re-evaluate methods for producing sugar from cane. These technologies allow more water and lime to be used, and they add more value to bagasse. Extracting and preserving the sugars, and lime pretreating the bagasse to enhance biodigestibility, all at the same time in a pile, was demonstrated to be unfeasible; therefore, sugar extraction must occur before lime treating the bagasse. Sugar extraction should occur countercurrently by lixiviation, where liquid moves in stages opposite to the soaked bagasse (megasse), which is conveyed by screw-press conveyors that gently squeeze the fiber in each stage, improving extraction. The performance of a pilot-scale screw-press conveyor was tested for dewatering capabilities and power consumption. The unoptimized equipment decreased megasse moisture from 96 to 89%. Simulation of the process suggested that eight stages are necessary to achieve 98% recovery from typical sugarcane. The cumulative power for the screw-press conveyor system was 17.0±2.1 hp•h/ton dry fiber. Thin raw juice preserved with lime for several months showed no sucrose degradation and no quality deterioration, except for reducing sugar destruction. The lime loading needed for 1-year preservation is 0.20 g Ca(OH)2/g sucrose. Shorter times require less lime. After preservation, the juice was carbonated and filtered, and the resulting sludge pelletized. Due to their high organic content, the pellets were too weak for calcination temperatures used in the SLK. The organics must be decreased prior to pelletization and sodium must be supplemented as a binding agent. Long-term lime pretreatment of bagasse showed two delignification phases: bulk (rapid) and residual (slow). These were modeled by two simultaneous first-order reactions. Treatments with air purging and higher temperatures (50 – 57oC) delignified more effectively, especially during the residual phase, thus yielding higher cellulase-enzyme digestibilities after 2 – 8 weeks of treatment. At temperatures > 60oC, pure oxygen purging is preferred. Fresh bagasse was of better quality than old bagasse. Treatment with NaOH yielded a larger bulk delignification phase than Ca(OH)2. Long-term lime pulping of bagasse was unsuitable for copy-quality paper, but it was appropriate for strawboard and other filler applications.

Historically, the production and exportation of sugar have been of immense significance for Cuba and although sugar remains to be the product of most vitality in the mills the diversification of sugar cane usage is now of a greater extent. This development has resulted in an increased production and consequently the mills provide by-products in a more considerable degree. The by-product of concern in this report is the sugar cane bagasse, which is used to fuel the boilers in the cogeneration unit in order to provide the electricity and heat needed for processing sugar. However, depending on the level of technological development within the mills, excess bagasse is being produced and by traditional terms causing a disposal problem. Conversely, the bagasse has vast potential within numerous different applications.    Carlos Baliño is situated in the province of Villa Clara and it is the only mill in Cuba that produces organic sugar. The mill is completely self-sufficient in its energy needs and moreover the mechanical steam turbines for the crushing and milling section have been exchanged to electrical drives and a bagasse boiler has been replaced by a more efficient one. These technological developments have resulted in excess bagasse being produced in a significant scale. The aim of the study presented in this report is to provide a suggestion of a suitable application of the excess by overlooking different ways of storing bagasse; pelletizing is one option that will be analysed. As the production of sugar and thereby bagasse is seasonal and the harvesting seasonality causes variations in the production the suggestion requires a numerical model that describes the nominal amount of excess bagasse in relation to the practical amount, based on the flows in the sugar mill. Furthermore, an economic evaluation of the chosen application with the aim of elucidating the potential of the stored bagasse as a source of income is presented in the report as well as an analysis of how the ash content affects the value of the bagasse.    Results showed that pelletizing is a suitable application for the excess bagasse at Carlos Baliño. The cost of capital for the considered pellet plant investment has been determined to 3,3 million USD and the breakeven investment cost to 4,7 million USD. Yet the economical calculations regarding the pellet plant investment have been based on a modest scenario it is profitable. Considering the vast difference between the nominal and the practical amount of excess bagasse Carlos Baliño has a great potential in increasing the amount of pellets produced as well as the financial gain.    Future work should suggestively focus upon improving the circumstances in which Carlos Baliño will produce and sell pellets in order to moreover enlarging the commercialisation scale of Cuban bagasse pellets. This report states the potential and the possibilities within the investigated market and can furthermore constitute the foundation upon which future studies regarding possible optimizations within the frames of the cogeneration unit with focus on the boiler efficiency, unplanned production stops as well as revenue based production optimization.
Produktion samt export av socker har på ett historiskt plan haft en oerhörd betydelse för Kuba. Trots att socker är den dominanta produkten vid vilken fabrikerna lägger störst vikt så är numera användandet av sockerrör diversifierat i en bredare omfattning. Denna utveckling har resulterat i en ökad produktion och således produceras även restprodukter i en mer betydande skala. I denna studie ligger fokus vid restprodukten bagasse, vilken används som bränsle för att producera den elektricitet och värme som krävs av processerna i fabriken. Beroende på graden av teknisk utveckling inom fabriken så produceras även överskottsbagasse vilken ur traditionella perspektiv ses som ett avfallsproblem ur hanteringssynpunkt. Emellertid har bagasse en stor potential och kan appliceras inom flera olika områden.   Carlos Baliño ligger i provinsen Villa Clara och är den enda sockerfabriken i Kuba som producerar organiskt socker. Fabriken är helt och hållet självförsörjande i sitt energibehov och har vidare bytt ut de mekaniska ångturbinerna för kross- och kvarnsektionen till elektriska motorer och en ångpanna för förbränning av bagasse är utbytt mot en mer effektiv. Dessa tekniska utvecklingar har resulterat i att överskottsbagasse produceras i en ansenlig omfattning. Målet med studien som är presenterad i denna rapport är att utforma ett förslag på en lämplig applikation av överskottsbagassen genom att undersöka olika sätt att nyttja denna; pelletering är ett alternativ som har analyserats. Eftersom produktionen av socker och följaktligen också bagasse är säsongsbaserad och med anledning av variationer i skörden krävs en numerisk metod vilken beskriver den nominella mängden av överskottsbagasse i relation till den praktiska mängden, baserat på flödena i fabriken. Vidare presenteras en ekonomisk analys av den föreslagna applikationen i syfte att framhäva potentialen av bagasse som inkomstkälla. Med avsikt att diskutera hur värdet av bagasse kan påverkas av dess innehåll av aska har också en analys av askans effekter utformats.    Studiens resultat visar på att en lämplig applikation för överskottsbagassen på Carlos Baliño är pelletering. Kapitalkostnaden för investeringen vilken avser pelletsproduktion bestämdes till 3,3 miljoner USD och jämviktskostnaden för investeringen till 4,7 miljoner USD. Trots att de ekonomiska uträkningarna baserades på ett modest scenario visar resultaten på ekonomisk lönsamhet. Vidare finns för Carlos Baliño en stor potential i att öka mängden producerad pellets och vidare också den ekonomiska vinningen. Denna potential utgörs av den betydande skillnaden mellan nominell och praktisk mängd av överskottsbagasse.   Framtida arbete borde förslagsvis fokusera på att förbättra de omständigheter under vilka Carlos Baliño kommer producera och sälja pellets. Detta i syfte att sedermera öka kommersialiseringsskalan av kubansk bagassepellets. Denna rapport visar på potential och möjligheter inom den undersökta marknaden och utgör vidare grunden till framtida studier rörande möjliga optimeringar inom ramarna för förbränningseffektivitet, oplanerade produktionsstopp och vinstbaserad produktionsoptimering.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references (leaf 61).
Charcoal made from bagasse, the fibrous remains of sugarcane production, has the potential to serve as an alternate cooking fuel in Haiti, where the reliance on wood has led to severe deforestation. Current production methods for charcoal briquettes range from laborious hand- forming to expensive industrial machinery. Thus, there is a need for an intermediate technology. This thesis describes the development of an affordable, locally manufacturable, briquette-making device that produces higher quality charcoal than hand-formed briquettes. The device is intended for small-scale briquette production in rural villages to supply charcoal to local markets. Since little is known about the materials properties and characteristics of bagasse charcoal, several production possibilities have been considered and evaluated. The most important finding during this process was that impact loading is more effective than steady compression because the required forces are not easily achievable by simple mechanisms. The final concept is a pile driver press, which uses a hammer to strike a metal piston and drive it into a tall channel to compact a column of charcoal. Several briquettes can be formed at once by using thin spacers to separate sections of charcoal within the channel.
(cont.) A single channel prototype has been constructed as a proof-of-concept model. Cylindrical briquettes formed using this prototype had an average density of 0.29 g/cm3, and an average radial failure load of 390 N. Commercially available Kingsford charcoal had an average density of 0.80 g/cm3 and the compressive strength was 590 N. Although the hammered briquettes were not as strong as commercial charcoal available in the United States, they should still be able to withstand the loads imposed during transport in Haiti. More tests and refinement of the design are needed, but overall the pile driver press has great potential to eventually be adopted in Haiti as a small-scale briquette-making device.
by Jessica Vechakul.
S.B.

To reduce formaldehyde emissions and prevent deforestation, particle boards prepared from sodium hydroxide modified algae and sugarcane bagasse were used to study the effect of process parameters such as fine-filler ratio, algae-filler ratio, ambient storage times, and sodium hydroxide concentration on mechanical properties. P-test was conducted to test for significance of parameters on flexural modulus and flexural strength. Results showed that algae-filler ratio and ambient storage times have significant impact on mechanical properties, while fine-filler ratio showing significant impact on secant flexural modulus and sodium hydroxide concentration having impact only on tangent flexural modulus. Mechanical properties of particleboard composites made from sugarcane bagasse and spirulina algae were found to be comparable to conventional particle boards.

In the last few centuries the world-wide energy demand rose to a stage were traditional power-supply networks struggle to satisfy the necessary supply of energy. Consequently, humanity is still largely dependent on every energy source possible and primarily environmentally unfriendly sources such as coal, fossil-oils, nuclear etc. Governments world-wide finally realised that those recourses are limited and began to subsides renewable energy solutions such as solar and wind energy, but by neglecting the fact that those sources have problems to supply energy 24/7 to the customers. Pyrolysis from bio feedstock is one of the technologies which can not only produce oil and gas for generators as well as fertiliser, but also conquer another problem arising from modern society, garbage reduction. Pyrolysis does exist for many years now, but the technology has not often been employed due to high initial investments, maintenance, and other factors. Furthermore, most of the conducted pyrolysis laboratory experiments also focused on expensive setups, catalysts etc., which create potentially good results, but consequently the pyrolysis process continued of being unaffordable for private consumers and especially for smaller businesses, such as farmers. Several research projects focussed on the yield output, rather than the quality of the oil which could be used for power generation. As a result, the usage of the oil was not suitable for generators or even for storing, due to impurities as well as due to forming of aromatics which occur very often in the aim of maximising the yield output and causes wax deposits, which can cause severe damage in machines operated with fuel produced from this oil. In this research pyrolysis experiments were conducted with the focus on increasing the oil quality by changing the temperature parameters, with a setup which is as simple as possible in order to make the setup mainstream capable, but also with the possibility of upscaling in mind. Although there are numerous feedstocks to choose from, sugarcane bagasse was chosen to be the feedstock of this research. This feedstock appears to be ideal, as the consumption and therefore the sugarcane bagasse waste rose significantly in the last century. At first the simplistic test rig was designed to determine the most suitable heating ramps and finally to investigate maximum temperatures from 300⁰C up to 650⁰C, based on the literature review conducted. This returned an overall picture at what temperature the best possible oil output for this feedstock and simplistic set-up can be. After analysis of the different oil outputs, the temperature range was more refined and the ramp, which proved to be the best, was fixed. The final analysis is conducted in a narrowed temperature band of 450⁰C to 550⁰C and showed very promising results at 550⁰C not only in regard of a 11% increase of the higher heating value, which would mean that if a person consumes an average of 800kwh per year and everybody on this planet would use pyrolysis as a primary energy source, 38 million tonnes less of feedstock would be needed per year world-wide. Furthermore, storage capabilities of oil produced by 550⁰C showed an immense storage capability improvement, due to a very low amount of aromatics in comparison to temperatures above and below 550⁰C. Furthermore, the analysis was repeated four months after the experiments to observe any build-up of wax deposits from possible aromatics. The results were found to be exactly the same in regard to the HHV as well as the FTIR spectra of oil. Overall the research project proved that pyrolysis can be affordable, but also can produce good quality oil at the same time. Consequently, pyrolysis can play a vital role in the run for sustainable energy resources in the future.
Thesis (Masters)
Master of Philosophy (MPhil)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text

With recent emphasis on development of alternatives to fossil fuels, sincere attempts are being made on finding suitable lignocellulosic feedstocks for biochemical conversion to fuels and chemicals. Sweet Sorghum is among the most widely adaptable cereal grasses, with high drought resistance, and ability to grow on low quality soils with low inputs. It is a C4 crop with high photosynthetic efficiency and biomass yield. Since sweet sorghum has many desirable traits, it has been considered as an attractive feedstock. Large scale sweet sorghum juice extraction results in excessive amounts of waste sweet sorghum bagasse (SSB), which is a promising low cost lignocellusic feed stock. The ability of two pretreatment methods namely conventional oven and microwave oven pretreatment for disrupting lignocellulosic structures of sweet sorghum bagasse with lime [Ca(OH)2] and sodium hydroxide [NaOH] was evaluated. The primary goal of this study was to determine optimal alkali pretreatment conditions to obtain higher biomass conversion (TRS yield) while achieving higher lignin reduction for biofuel production. The prime objective was achieved using central composite design (CCD) and optimization of biomass conversion and lignin removal simultaneously for each alkali separately by response surface method (RSM). Quadratic models were used to define the conditions that separately and simultaneously maximize the response variables. The SSB used in this study was composed of cellulose, hemicellulose, and lignin in the percentage of 36.9 + 1.6, 17.8 + 0.6, and 19.5 + 1.1, respectively. The optimal conditions for lime pretreatment in the conventional oven at 100 °C was 1.7 (% w/v) lime concentration (=0.0024 molL-1), 6.0% (w/v) SSB loading, 2.4 hr pretreatment time with predicted yields of 85.6% total biomass conversion and 35.5% lignin reduction. For NaOH pretreatment, 2% (w/v) alkali (=0.005 molL-1), 6.8% SSB loading and 2.3 hr duration was the optimal level with predicted biomass conversion and lignin reduction of 92.9% and 50.0%, respectively. More intensive pretreatment conditions removed higher amount of hemicelluloses and cellulose. Microwave based pretreatments were carried out in a CEM laboratory microwave oven (MARS 6-Xpress Microwave Reactions System, CEM Corporation, Matthews, NC) and with varying alkali concentration(0.3 - 3.7 % w/v) at varying temperatures (106.4 - 173.6 °C), and length of time (6.6 - 23.4 min). The NaOH pretreatment was optimized at 1.8 (% w/v) NaOH, 143 °C, 14 min time with predicted yields of 85.8% total biomass conversion and 78.7% lignin reduction. For lime pretreatment, 3.1% (w/v) lime, 138 °C and 17.5 min duration was the optimal level with predicted biomass conversion and lignin reduction of 79.9% and 61.1%, respectively. Results from this study were further supported by FTIR spectral interpretation and SEM images.

Pressure feeder chutes are pieces of equipment used in sugar cane crushing to increase the amount of cane that can be put through a mill. The continuous pressure feeder was developed with the objective to provide a constant feed of bagasse under pressure to the mouth of the crushing mills. The pressure feeder chute is used in a sugarcane milling unit to transfer bagasse from one set of crushing rolls to a second set of crushing rolls. There have been many pressure feeder chute failures in the past. The pressure feeder chute is quite vulnerable and if the bagasse throughput is blocked at the mill rollers, the pressure build-up in the chute can be enormous, which can ultimately result in failure. The result is substantial damage to the rollers, mill and chute construction, and downtimes of up to 48 hours can be experienced. Part of the problem is that the bagasse behaviour in the pressure feeder chute is not understood well. If the pressure feeder chute behaviour was understood, then the chute geometry design could be modified in order to minimise risk of failure. There are possible avenues for changing pressure feeder chute design and operations with a view to producing more reliable pressure feeder chutes in the future. There have been previous attempts to conduct experimental work to determine the causes of pressure feeder chute failures. There are certain guidelines available, however pressure feeder chute failures continue. Pressure feeder chute behaviour still remains poorly understood. This thesis contains the work carried out between April 14th 2009 and October 10th 2012 that focuses on the design of an experimental apparatus to measure forces and visually observe bagasse behaviour in an attempt to understand bagasse behaviour in pressure feeder chutes and minimise the risk of failure.

O fungo filamentoso Trichoderma reesei é um dos principais fungos utilizados para a produção em larga escala de enzimas devido a sua grande capacidade de produção e secreção de holocelulases para aplicação em processos de sacarificação da biomassa vegetal lignocelulósica. Embora o T. reesei seja utilizado como um dos principais produtores de celulases a nível industrial, diversos processos e estudos são realizados com o objetivo de aprimorar o entendimento de todo o mecanismo de degradação de biomassa vegetal além de prover o aumento da eficiência tanto da produção quanto da atividade das celulases. No presente trabalho foi realizado a construção de uma linhagem mutante para o gene cel74a (codificando para uma xiloglucanase) e a caracterização funcional de CEL74A na regulação gênica de holocelulases durante o cultivo em bagaço de cana-de-açúcar. Os nossos resultados mostraram que deleção de cel74a possivelmente pode estar envolvida no sinergismo da regulação da expressão de holocelulases durante o cultivo em bagaço de cana-de-açúcar. A partir da análise do perfil de expressão gênica, foi possível observar a redução na expressão de todos os genes de celulases testados (cel7a, cel7b e cel6a) embora não tenha afetado a atividade enzimática, ao passo que as hemicelulases (xyn1 e xyn2) apresentaram aumento tanto na expressão quanto na atividade enzimática. Na linhagem ?cel74a, foi observado redução na liberação de glicose, xilose e galactose após a hidrólise de xiloglucano. Além disso, a atividade de CEL74A foi modulada na presença de cálcio e pode ser necessária para a atuação mais eficiente de outras enzimas envolvidas na degradação de xiloglucano. Desta forma, em T. reesei, CEL74A apresenta um papel importante tanto na regulação de genes holocelulolíticos quanto para a degradação eficiente de bagaço de cana-de-açúcar, contribuindo para a elucidação de mecanismos pelos quais este fungo utiliza para a utilização do bagaço de cana-de-açúcar como fonte de carbono
The filamentous fungus Trichoderma reesei is one of the main fungi used for the large-scale production of enzymes due to their great capacity of production and secretion of holocellulases for application in saccharification processes of lignocellulosic plant biomass. Although T. reesei is used as one of the main producers of cellulases at industrial level, several processes and studies are carried out with the aim of improving the understanding of the whole plant biomass degradation mechanism, as well as increasing the efficiency of both the production and cellulase activity. In the present work the construction of a mutant lineage for the cel74a gene (coding for a xyloglucanase) and the functional characterization of CEL74A in the gene regulation of holocellulases during the cultivation of sugarcane bagasse were carried out. Our results showed that deletion of cel74a may be involved in the regulation of holocellulase expression during sugarcane bagasse cultivation. From the analysis of the gene expression profile, it was possible to observe the reduction in the expression of all tested cellulase genes (cel7a, cel7b and cel6a), although it did not affect the enzymatic activity, whereas the hemicellulases (xyn1 and xyn2) presented increase in both expression and enzymatic activity. In the ?cel74a strain, a reduction in glucose, xylose and galactose release was observed after xyloglucan hydrolysis. In addition, the activity of CEL74A was modulated in the presence of calcium and may be required for the more efficient performance of other enzymes involved in the degradation of xyloglucan. Thus, in T. reesei, CEL74A plays an important role both in the regulation of holocellulolytic genes and in the efficient degradation of sugarcane bagasse, contributing to the elucidation of mechanisms by which this fungus uses for the use of sugarcane bagasse as source of carbon

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Apresenta-se o estudo experimental do comportamento de um solo arenoso e de um solo argiloso, reforçado e não reforçado com cinza de bagaço de cana-deaçúcar e com cinza de casca de arroz, por meio da realização de ensaios de caracterização física e química e de ensaios de cisalhamento direto. Busca-se estabelecer padrões de comportamento que possam explicar a influência da adição das cinzas, relacionando-os com os parâmetros de resistência ao cisalhamento e de deformação do solo. Os ensaios foram realizados em amostras com teores que variaram entre 5-20 por cento. Por meio dos resultados obtidos, foi possível concluir que a inserção de cinza de bagaço de cana-de-açúcar, aos solos argiloso e arenoso em estudo, mostra-se viável, uma vez que resultaram em melhoria dos parâmetros de resistência ou não causaram alterações significativas. Para a cinza de casca de arroz, em misturas com solo arenoso, a aplicação não se mostrou viável, visto que, para ambos os teores de cinza, houve um decréscimo no ângulo de atrito e nenhum acréscimo de coesão. Nas misturas com solo argiloso, a aplicação da mesma cinza mostrou-se viável, haja vista que sua aplicação resultou em melhoria dos parâmetros de resistência. Quanto ao teor de cinza para as misturas com solo argiloso, verificou-se que o melhor comportamento obtido foi com o teor de 20 por cento, para as misturas com ambas as cinzas. Para as misturas com areia, como não houve um aumento proporcional da resistência com o aumento do teor das cinzas foi difícil determinar um teor ótimo de cinza a ser utilizado. Os resultados obtidos neste estudo, em geral, mostraram-se satisfatórios e cumpriram os objetivos iniciais propostos com relação à investigação do comportamento solo-cinza para utilização em obras geotécnicas.
This paper presents the experimental study of the behavior of a sandy soil and a clay soil, reinforced and unreinforced with sugarcane bagasse ash and rice husk ash, by performing physical and chemical characterization tests and direct shear tests. The aim is to establish patterns of behavior that may explain the influence of the addition of ashes, relating them to the shear strength parameters and soil deformation. The tests were carried out on samples with concentrations ranging from 5-20 percent. Through the results, it was possible to conclude that the inclusion of sugarcane bagasse ash, to clay and sandy soils under study, proves viable, since it resulted in improved strength parameters or did not cause significant alterations. For the rice husk ash in mixtures with sandy soil, the application was not feasible, since for both ash contents there was a decrease in the friction angle and no increase in the cohesion. In blends with clay soil, the application of the same ash proved to be feasible, given that its application resulted in improvement of resistance parameters. As for the ash content for mixtures containing clay soil, it was found that the best performance was obtained with 20 percent content for mixtures with both ashes. For mixtures with sand, as there was not a proportional increase in resistance with increasing content of ash it was difficult to determine an optimal ash content to be used. The results of this study generally were satisfactory and met the initial proposed objectives in relation to soil-ash behavioral research for use in geotechnical works.

The research presented in this thesis was developed as part of DIBANET, an EC funded project aiming to develop an energetically self-sustainable process for the production of diesel miscible biofuels (i.e. ethyl levulinate) via acid hydrolysis of selected biomass feedstocks. Three thermal conversion technologies, pyrolysis, gasification and combustion, were evaluated in the present work with the aim of recovering the energy stored in the acid hydrolysis solid residue (AHR). Mainly consisting of lignin and humins, the AHR can contain up to 80% of the energy in the original feedstock. Pyrolysis of AHR proved unsatisfactory, so attention focussed on gasification and combustion with the aim of producing heat and/or power to supply the energy demanded by the ethyl levulinate production process. A thermal processing rig consisting on a Laminar Entrained Flow Reactor (LEFR) equipped with solid and liquid collection and online gas analysis systems was designed and built to explore pyrolysis, gasification and air-blown combustion of AHR. Maximum liquid yield for pyrolysis of AHR was 30wt% with volatile conversion of 80%. Gas yield for AHR gasification was 78wt%, with 8wt% tar yields and conversion of volatiles close to 100%. 90wt% of the AHR was transformed into gas by combustion, with volatile conversions above 90%. 5volO2%-95vol%N2 gasification resulted in a nitrogen diluted, low heating value gas (2MJ/m3). Steam and oxygen-blown gasification of AHR were additionally investigated in a batch gasifier at KTH in Sweden. Steam promoted the formation of hydrogen (25vol%) and methane (14vol%) improving the gas heating value to 10MJ/m3, below the typical for steam gasification due to equipment limitations. Arrhenius kinetic parameters were calculated using data collected with the LEFR to provide reaction rate information for process design and optimisation. Activation energy (EA) and pre-exponential factor (ko in s-1) for pyrolysis (EA=80kJ/mol, lnko=14), gasification (EA=69kJ/mol, lnko=13) and combustion (EA=42kJ/mol, lnko=8) were calculated after linearly fitting the data using the random pore model. Kinetic parameters for pyrolysis and combustion were also determined by dynamic thermogravimetric analysis (TGA), including studies of the original biomass feedstocks for comparison. Results obtained by differential and integral isoconversional methods for activation energy determination were compared. Activation energy calculated by the Vyazovkin method was 103-204kJ/mol for pyrolysis of untreated feedstocks and 185-387kJ/mol for AHRs. Combustion activation energy was 138-163kJ/mol for biomass and 119-158 for AHRs. The non-linear least squares method was used to determine reaction model and pre-exponential factor. Pyrolysis and combustion of biomass were best modelled by a combination of third order reaction and 3 dimensional diffusion models, while AHR decomposed following the third order reaction for pyrolysis and the 3 dimensional diffusion for combustion.

The present study investigated the feasibility of using Nile red fluorescent method for measuring cellular neutral lipid content as well as the capability of Cryptococcus curvatus to utilize sugars in hydrolysates of sweet sorghum bagasse- an agriculture byproduct- for the production of lipids. Nile red is a fluorescent dye which is specific for intracellular neutral lipids. To generate biodiesel from microbial lipids through alkaline transesterification, only neutral lipids are readily convertible. Knowing the accurate content of neutral lipids in microbial cells is important for evaluating amount of biodiesel that can be produced. To develop the Nile red protocol, different wavelengths for excitation and emission were investigated together with different cell numbers and cell-dye contact time. In this study, Nile red was proven to be capable of serving as an excellent dye for quantifying cellular neutral lipid content in C. curvatus. The obtained protocol can certainly be applied for other purposes, for example, high throughput screening of oleaginous species with high lipid content and measuring neutral lipid concentration in any other microbial cells. Cryptococcus curvatus, one of the most efficient yeast candidates for lipid production, can accumulate more than 60% of dry biomass as lipids on a broad range of mono- and disaccharides and sugar alcohols. In separate batch studies,Cryptococcus curvatus was grown and monitored on both pure sugar substrate and sorghum hydrolysates. Like other oleaginous yeast species, C. curvatus can uptake glucose and xylose simultaneously. Interestingly, this yeast can also utilize cellobiose. Sweet sorghum, a C4 plant possessing high photosynthetic efficiency, high sugar yield but low requirements for fertilizer and water has been identified as an excellent biofuel feedstock. After sweet sorghum juice is extracted, the left bagasse poses a disposal problem and its usage as fodder for animals is not a sufficient approach. Sweet sorghum juice has been reported for ethanol and biodiesel production due to the high sugar content. However, no special attention has been given so far to the utilization of the sweet sorghum bagasse for biodiesel production through microbial fermentation. The main components of sweet sorghum bagasse are cellulose, hemicellulose, and lignin. To release fermentable sugars from sorghum bagasse, we have tested lime-assisted microwave pretreatment. The pretreated material was then subjected to enzymatic hydrolysis using commercial enzymes. The hydrolysates obtained were used for lipid accumulation by yeast Cryptococcus curvatus. With sweet sorghum hydrolysates derived from microwave pretreatment with lime, the maximal yeast cell dry weight and lipid content were 10.83 g/l and 73.26%, respectively. For hydrolysates developed from microwave pretreatment without lime, these two parameters were 15.50 g/l and 63.98%, respectively. As a result, higher lipid yield of 0.11 g/g bagasse or 0.65 ton/hectare of land was achieved from bagasse pretreated by microwave followed by enzymatic hydrolysis while 0.09 g/g bagasse or 0.51 ton/hectare of land was attained from the same process but with lime during microwave pretreatment. With sweet sorghum hydrolysates derived from oven pretreatment with lime, maximal cell biomass dry weight as 6 g/l was achieved in 5 days. Maximal neutral lipid content as 2.6 g/l was observed by day 3. Neutral lipid yield (g neutral lipid/g sugar) was calculated as 0.19 which is close to the theoretical value. This research shows that the hydrolysates of sweet sorghum bagasse can be utilized by Cryptococcus curvatus to yield substantial quantities of lipids. Based upon the results revealed from the batch stage studies, large scale lipid production from this agricultural by-product could be a reality in the near future. This production process will: 1) produce high-value lipids in an environmentally friendly, economical, and sustainable way, and 2) provide lipid feedstocks for various industrial applications.

碩士
臺灣大學
生物產業機電工程學研究所
95
Bioethanol is a kind of clean and renewable energy which can be used directly or mixed with gasoline as fuel on vehicles. In this study, sugarcane bagasse which contained 33.34% cellulose, 22.11% semicellulose, and 6.49% lignin was pretreated by 0.25 M sulfuric acid under 95℃ and 1 atm pressure for 60 mins. After pretreatment, dried solid material was hydrolyzed by mixing enzymes of cellulase from Trichoderma reesei C2730 (Celluclast 1.5L) and cellobiase from Aspergillus niger (Novozyme 188) under conditions of pH 4.6, 50℃ in 80 rpm shaking water bath for 24 hours. Different enzyme loadings and substrate ratios were tested to find out the optimum parameters. Hydrolysate was then fermented with Saccharomyces cerevisiae BCRC 21685 under conditions of pH 4.6, 30℃ for 24-48 hours. The effect of additional glucose, sterilization, and detoxification were investigated in this step. As result, 0.52 mg/mL of glucose and 4.29 mg/mL of xylose concentrations were observed in liquid fraction and the content of solid material showed that 91.85% semicellulose and 1.46% cellulose was removed in pretreatment. In hydrolysis step, the enzyme loading of 5 mL Celluclast 1.5L plus 1 mL Novozyme 188 represented the best balance between economy and efficiency. 339.21 mg/mL of yield and 49.25% of conversion ratio were obtained under this enzyme loading with 1% substrate ratio and rising the substrate ratio did not help improving both of them. In fermentation step, without sterilization and detoxification, 26.7 g/L of glucose remains after 48 hours fermentation and ethanol yield was 0.367 g ethanol / g glucose, corresponding to 72% of theoretical ethanol yield. With sterilization and detoxification, glucose was fermented within 24 hours. The ethanol yield was 0.43 g ethanol/g glucose, , corresponding to 84% of theoretical ethanol yield. With evaporation to enhance the glucose concentration, the glucose concentration did not decrease to zero until after 30h. The ethanol concentration was 40.7 g/L, corresponding to 79% of theoretical ethanol yield.

PURPOSE OF THE PROJECT Bio-fuel has been a source of energy that human beings have used since ancient times. Increasing the use of bio-fuels or energy generation purposes is of particular interest nowadays because they allow mitigation of greenhouse gases, provide means of energy independence and may even offer new employment possibilities. Bio-fuels are being investigated as potential substitutes for current high pollutant fuels obtained from conventional sources. The aim of the project is the production of low cost ethanol by using lignocellulosic materials basically the agro wastes like sugarcane bagasse, rice husk, wheat straw, corn fiber, crop residues, grasses and other materials like saw dust, wood chips, solid animal wastes etc. BREIF DESCRIPTION OF THE EXPERIMENT The raw material used for the experiment is bagasse. First the bagasse is chipped and grinded (may be upto powder form). Then this is taken for acid hydrolysis. Dilute sulphuric acid of 0.2M, 0.3M and 0.5M concentration were used in this process. For the acid hydrolysis, 5 gms of bagasse was put in 100 ml of each of the concentrations and was allowed to soak for 1 day. Then it was auto-claved for half an hour and allowed to cool. The fermenting media was prepared. 5 gms of yeast was added to the above media and kept in incubator for 1 day. 10 ml of this media was added to each of the samples in asceptical (laminar flow hood) manner and placed in orbital shaking incubator. The ph was adjusted to 5 and the fermenting temperature was kept at 35 0 C.Fermentation may take upto 10 days. ANALYSIS OF ETHANOL AND SUGAR Sugar is analyised by DNS method. For ethanol analysis, after each interval of 24 hrs, 5 ml of the sample is taken and filtered. The filtrate is to be analyzed under UVspectrophotometer. Quantification of ethanol was done by using standard ethanol. RESULTS AND DISCUSSION The ethanol concentration increased as the number of days increased. The following graphs show the plot between the ethanol conc.in ml/lt vs number of days for 0.2M, 0.3M and 0.5M. The ethanol concentration decreased as the molarity of acid used (sulphuric acid) increased. The maximum concentration of ethanol obtained was 389.22 ml/lt of acid hydrolysed bagasse used.

University of Technology Sydney. Faculty of Engineering and Information Technology.
Expansive soils exhibit massive volume change against fluctuations of moisture content. Shrinkage and expansion of soil can commonly take place near the ground surface, where it is directly subjected to seasonal and environmental variations. Construction of civil engineering structures on expansive soils is highly risky, as this type of soil is susceptible to seasonal drying and wetting cycles, causing significant deformations. Frequent soil movements can generate cracks and damage residential buildings, roads, and other civil structures directly placed on this type of problematic soil. Many efforts have been applied in practice to overcome the adverse effects of expansive soil including replacement of existing expansive soil with non-expansive soil, maintaining a constant moisture content, and ground improvement techniques such as the application of granular pile-anchors, sand cushion technique, and belled piers, and soil stabilisation with chemical agents (e.g. lime or cement) and so on. On top of that, lime stabilisation is the most commonly used method for controlling the shrink-swell behaviour of expansive soil due to seasonal variations. Lime reacts with expansive clay in the presence of water and changes the physicochemical properties of expansive soil, which in turn alters the engineering properties of treated soil. Moreover, soil stabilisation and reinforcement using lime combined with agricultural and industrial waste by-products (e.g. fly ash, rice husk ash, recycled fibres) can extend the effectiveness of lime stabilised expansive soil. This study presents an experimental investigation on the improvement of the geotechnical properties of expansive soil stabilised with bagasse fibre, bagasse ash combined without or with lime stabilisation. The agricultural waste by-products of bagasse ash and fibre, remained after crushing of sugar-cane for juice extraction, and the expansive soils, used in this investigation, were collected from Queensland, Australia. The stabilised soil specimens were prepared by changing the contents of bagasse ash from 0% to 25%, bagasse fibre from 0% to 2%, hydrated lime from 0% to 6.25%, and combined bagasse ash-hydrated lime from 0% to 25% by the dry mass of expansive soil. Several series of laboratory experiments have been performed on untreated and treated expansive soil samples with different additive contents and various curing times of 3, 7, 28, and 56 days. Another extensive microstructural analysis using scanning electron microscopy (SEM), pH measurements, and Fourier transform infrared (FTIR) techniques has been carried out to evaluate the microstructure development of untreated and treated expansive soils. The outcomes of these experimental investigations showed that when the addition of bagasse ash into the expansive soils increased from 0% to 25%, the linear shrinkage reduced by 47%, the free swell potential decreased from approximately 10% to less than 0.5%, the swelling pressure reduction was from 80 kPa to 35 kPa (about 60%), the compressive strength at failure and the corresponding strain increased significantly by 48% and 40%. Meanwhile, the combination of bagasse ash and lime to stabilise soils when combined additive content increased up to 25% caused a significant increase in the compressive strength of 815% and the secant modulus of elasticity from 7.2 MPa to 107.2 MPa; reduced the linear shrinkage of 84% and the free swell potential down to less 0.5%; significantly decreased the swelling pressure from 80 kPa to around 10 kPa (88% reduction) and the compression indices from 0.484 to 0.083, just to name a few. It was noted that the improved geotechnical characteristics were more pronounced for lime treated soils with the combination of bagasse ash or fibre. The utilisation of bagasse ash or fibre for expansive soil stabilisation without or with lime combination not only effectively improved the geotechnical properties of expansive soil as curing time and additive content increased, but also assisted in minimising the adverse effects of agricultural waste by-products on the environment. Numerical investigations based on the finite element method (FEM) incorporated in PLAXIS were carried out to evaluate a possible practical application of recycled fibre-lime reinforced soil as a replacement of geosynthetic reinforced traditional angular load transfer platform layer combined with columns or piles supported embankments founded on soft soils. An equivalent two-dimensional FEM model with proper modified parameters of structure and soil models has been adopted to investigate the performance of floating columns supported embankment reinforced without or with an FRLTP (fibre reinforced load transfer platform). Firstly, a series of numerical analysis was performed on the full geometry of columns supported embankment reinforced without or with an FRLTP of 0.5 m to examine the effectiveness of the FRLTP inclusion into the columns supported embankment system. The numerical results revealed that the embankment with FRLTP could effectively reduce the total and differential settlements, and the lateral displacement of the embankment by 20%, 74% and 46%, respectively, when compared with the embankment without FRLTP. Subsequently, several series of extensive parametric studies on the influence of FRLTP properties, and the improvement depth ratios of soft soils, have been carried out to assess the behaviour of the columns supported embankment with FRLTP. The findings of the extensive parametric study indicated that the platform thickness has a significant influence on the embankment behaviour, especially in improving the total and differential settlements, the rigidity and stability of the embankment, and the more load transfer from the embankment to DCM columns. Meanwhile, Young’s modulus of the FRLTP shows considerable effects on the differential settlement, the stress concentration ratio, but has a negligible effect on the lateral deformation of the investigated embankment. The improvement depth ratio reveals substantial impacts on the final settlement and the lateral deformation, but shows insignificant influence on the stress concentration ratio and the differential settlement during the embankment construction and post-construction time. The FRLTP shear strength parameters show significant influences on the stress concentration ratio and the differential settlement of the embankment. However, the enhancement in the embankment performance was more noticeable for the cohesion than the internal friction angle of the FRLTP.

碩士
大同大學
化學工程學系(所)
94
The kinetic parameters of sugarcane bagasse with particle size (0.246 mm- 0.297 mm) performed at different heating rates (5 ℃/min, 20 ℃/min) were studied by TGA in the origin, demineralized and impregnated catalyst ones under air atmosphere. First order reaction combined kinetic temperature equation and Coats-Redfern method with different expressions of g (��) would be used to estimate activation energy, E, and pre-exponential factor, A. The results indicate that catalytic components do not always decrease the activation energy, and rather, small increases in activation energy. From the activation point of view, the order of the activity of catalyzers is K2CO3 >K2CO3+Ni(NO3)2 >K2SO4+Ni(NO3)2. This is a debatable border area. Finally, we infer that the reactivity order of the three catalyzers is K2SO4+Ni(NO3)2 >K2CO3+Ni(NO3)2 >K2CO3, because that not only activation energy (E) but also pre-exponential factor (A) would affect the values of the rate constant, k. The selection of degree of conversion determined by the final mass fraction, Wkf, is an important step in TGA analysis.

碩士
大同大學
化學工程研究所
93
The kinetic parameters of sugarcane bagasse with particle size (0.246 mm- 0.297 mm) performed at different heating rates (5℃/min, 20℃/min) were studied by TGA in the origin, demineralized and impregnated catalyst ones under air atmosphere. First order reaction combined kinetic temperature equation and Coats-Redfern method with different expressions of g () would be used to estimate activation energy, E, and pre-exponential factor, A. The results indicate that catalytic components do not always decrease the activation energy, and rather, small increases in activation energy. From the activation point of view, the order of the activity of catalyzers is K2CO3 >K2CO3+Ni(NO3)2 >K2SO4+Ni(NO3)2. This is a debatable border area. Finally, we infer that the reactivity order of the three catalyzers is K2SO4+Ni(NO3)2 >K2CO3+Ni(NO3)2 >K2CO3, because that not only activation energy (E) but also pre-exponential factor (A) would affect the values of the rate constant, k. The selection of degree of conversion determined by the final mass fraction, Wkf, is an important step in TGA analysis.

Submitted in fulfillment of the academic requirements for the Masters in Applied Sciences (Chemistry), Durban University of Technology, Durban, South Africa, 2016.
The main aim of this work was to produce levulinic acid (LA) from sugarcane bagasse (SB) and since there is approximately 3 000 000 tons of bagasse produced per annum by 16 factories that are located on the north coast of Kwa-Zulu Natal, after the extraction of sugar. For this project fructose was firstly used for the production of LA, thereafter SB was used to produce LA. Cellulose was extracted from sugarcane bagasse using two types of pre-treatments namely (i) acid-alkali pre-treatment and (ii) liquid hot water (LHW). In the latter method acid hydrolysis and enzymatic hydrolysis was used to hydrolyse cellulose to glucose. For the acid-alkali pre-treatment work, two types of bagasse was used namely (i) mill-run bagasse and (ii) depithed bagasse and for the LHW a mill-run bagasse (pellets form) was used. In both pre-treatment methods the glucose solution was then acid catalysed by two different acids (i) an environment friendly acid, methanesulfonic acid (MSA) and (ii) sulphuric acid, producing levulinic acid. The results showed that MSA and sulphuric acid produced almost the same yield of LA but, MSA is preferred for the production of LA since it is less toxic and less corrosive than sulphuric acid.
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