Дисертації з теми "Optimization of biomass formation"
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Shearer, Dustin. "Optimization of cellulosic biomass analysis." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/16995.
Повний текст джерелаDepartment of Agricultural Economics
Jeffery Williams
Ethanol has become an important source of energy for transportation purposes in the U.S. The majority of the feedstock for this ethanol is corn grain. The use of crop residues and perennial grasses has been proposed as an alternative feedstock for ethanol production using cellulosic conversion processes. Commercial scale production of cellulosic ethanol is still on the horizon. In the meantime a wide variety of studies examining both the technical and economic feasibility of cellulosic ethanol production have been conducted. This is the first study that combines both county level cellulosic feedstock production and farmer participation rates to determine the feasibility of supplying it to cellulosic ethanol plants. This research determines the economic feasibility of supplying cellulosic feedstocks to seven potential add-on cellulosic ethanol plants of 25 million gallons per year at seven existing starch ethanol plants in Kansas. The feedstocks considered are corn stover, sorghum stalks, wheat straw, and perennial switchgrass. A mixed integer programing model determines the amount and mix of cellulosic feedstocks that can be delivered to these plants over a range of plant-gate feedstock prices given transportation costs and farm-gate production costs or breakeven prices. The variable costs of shipping are subtracted from the difference between plant-gate price and farm-gate price to find savings to the plant. The objective function of the model minimizes transportation costs which in turn maximizes savings to the plant. The role switchgrass may have as a feedstock given various switchgrass production subsidies is examined. The results indicate the minimum plant-gate price that must be paid to feedstock producers for all plants to have enough cellulosic feedstocks is $75 per dry ton. Switchgrass feedstocks were only a minor portion of biomass supplied and used without a production subsidy. A Biomass Crop Assistance Program payment increased the supply of switchgrass more than other production subsidies.
Fitzpatrick, Emma Mary. "Biomass soot characterisation and formation mechanisms." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.530835.
Повний текст джерелаLim, Chun Hsion. "Biomass supply chain optimization : consideration of underutilised biomass via element targeting approach." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/38870/.
Повний текст джерелаNazeri, Gelareh. "Formation of Sugars and Organic Acids from Hydrothermal Conversion of Biomass and Biomass-Derived Sugars." Thesis, Curtin University, 2022. http://hdl.handle.net/20.500.11937/89694.
Повний текст джерелаStockenreiter, Maria. "Ecological optimization of biomass and lipid production by microalgae." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-148302.
Повний текст джерелаSay, Kevin. "Chemicals and Fuels from Biomass: Optimization of 2-Furaldehyde Production." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1447689678.
Повний текст джерелаNäzelius, Ida-Linn. "Slag formation in fixed bed combustion of phosphorus-poor biomass." Doctoral thesis, Luleå tekniska universitet, Energivetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-60303.
Повний текст джерелаShabani, Nazanin. "Value chain optimization of a forest biomass power plant considering uncertainties." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46406.
Повний текст джерелаZandi, Atashbar Nasim. "Modeling and Optimization of Biomass Supply Chains for Several Bio-refineries." Thesis, Troyes, 2017. http://www.theses.fr/2017TROY0038.
Повний текст джерелаBiomass can play a crucial role as one of the main sources of renewable energies. As logistics holds a significant share of biomass cost, efficient biomass supply chains must be designed to provide bio-refineries with adequate quantities of biomass at reasonable prices and appropriate times. This thesis focuses on modeling and optimization of multi-biomass supply chains for several bio-refineries. A data model is developed to list, analyze and structure the set of required data, in a logical way. The result is a set of tables that can be loaded into mathematical models for solving optimization problems. Then, a multi-period mixed integer linear programming model is proposed to optimize a multi-biomass supply chains for several bio-refineries, at the tactical and strategic level. Refineries can be already placed or located by the model. The aim is to minimize the total costs, including biomass production, storage, handling, refineries setup and transportation costs, while satisfying the demand of refineries in each period. Additionally, a multi-objective model is developed to optimize simultaneously the economic and environmental performance of biomass supply chains. The model is solved by using the ε-constraint method. Furthermore, large-scale tests on real data for two regions of France (Picardie & Champagne-Ardenne) are prepared to evaluate the proposed models. Finally, two-phase approaches are proposed to solve large-scale instances in reasonable running times, while evaluating the loss of optimality compared to the exact model
Moharreri, Ehsan. "Optimization, Scale Up and Modeling CO2-Water Pretreatment of Guayule Biomass." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1313013654.
Повний текст джерелаWu, Chunyang. "Fuel-NOx Formation during Low-Grade Fuel Combustion in a Swirling-Flow Burner." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1165.pdf.
Повний текст джерелаShah, Kalpit Vrajeshkumar. "Ash formation mechanisms during combustion/co-firing of biomass and coal." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/1502.
Повний текст джерелаLind, Terttaliisa. "Ash formation in circulating fluidised bed combustion of coal and solid biomass /." Espoo, Finland : Technical Research Centre of Finland, 1999. http://www.vtt.fi/inf/pdf/publications/1999/P378.pdf.
Повний текст джерелаFazenda, Mariana L. "Submerged culture fermentation of the Basidiomycete fungus Ganoderma lucidum for biomass formation." Thesis, University of Strathclyde, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501792.
Повний текст джерелаMa, Charlie. "Slag Formation During Pilot-Scale Pressurised Entrained-Flow Gasification of Woody Biomass." Licentiate thesis, Luleå tekniska universitet, Energivetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18723.
Повний текст джерелаGodkänd; 2014; 20141102 (chamaf); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Charlie Ma Ämne: Energiteknik/Energy Engineering Uppsats: Slag Formation During Pilot-Scale Pressurised Entrained-Flow Gasification of Woody Biomass Examinator: Professor Marcus Öhman, Institutionen för teknikvetenskap och matematik, Luleå Tekniska universitet Diskutant: Universitetslektor Christoffer Boman, Umeå Universitet Tid: Fredag den 12 december 2014 kl 10.00 Plats: E246, Luleå tekniska universitet
Josephson, Alexander Jon. "Modeling Soot Formation Derived from Solid Fuels." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7020.
Повний текст джерелаGiuliano, Aristide. "Process optimization of a lignocellulosic multi-product biorefinery." Doctoral thesis, Universita degli studi di Salerno, 2016. http://hdl.handle.net/10556/2364.
Повний текст джерелаA methodology to reduce the complexity of the process optimization was applied to multiproduct biorefinery fed by lignocellulosic biomass. A process superstructure was built to consider alternative process pathways to levulinic acid, succinic acid and ethanol. A Mixed Integer Non-Linear Problem was obtained and transformed in a Mixed Integer Linear Problem by means of a discretization procedure of the non-linear variables. Rigorous design methods accounting for complete kinetics schemes for hydrolysis and fermentation reactors for the production of levulinic acid, succinic acid and ethanol were included in a biorefinery superstructure optimization. A discretization method was applied to obtain a MILP approximation of the resulting MINLP master problem. The optimal flowsheet of a biorefinery with hardwood feedstock, obtained by maximizing the Net Present Value, yields comparable biomass allocation to levulinic acid and succinic acid (more than 40% each) and the its balance to ethanol. A sensitivity analysis highlighted that the optimal flowsheet and the relevant technical and economic performances are significantly dependent on the economic scenario (chemical products selling price, discount rate) and on the plant scale. Finally, process optimization achieved by maximizing two different economic objective functions, Net Present Value and Internal Rate of Return, provided different optimal flowsheets and biomass allocation to chemical products. The effect of the change of the biomass type and composition on the plant was also considered. Results highlight that the composition of the biomass feedstock in terms of cellulose, hemicellulose and lignin has a significant effect on the biomass allocation to the three product production processes and on the relevant optimal flowsheet. Case studies with a combined use of different seasonal biomass types during the year were also studied to provide a methodology to find the optimal biorefinery flowsheet in real scenarios. In the season based scenario studied, product yield distribution and overall productivity of the plant varies during the different periods provided a constant biomass feed rate. [edited by Author]
XIV n.s.
Hallmann, Fanfan Weng. "Uncertainty, Emerging Biomass Markets, and Land Use." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/37819.
Повний текст джерелаPh. D.
Xu, Feng. "Ethanol from photoperiod-sensitive sorghum: a study on biomass structure and process optimization." Diss., Kansas State University, 2012. http://hdl.handle.net/2097/16177.
Повний текст джерелаDepartment of Biological and Agricultural Engineering
Yong Cheng Shi
Donghai Wang
Cellulosic ethanol made from low cost lignocellulosic biomass has been considered as new generation transportation fuel with economic and environmental advantages. Photoperiod-sensitive (PS) sorghum, because of its high biomass yield (2.6 kg dry mass/m2), about 18% of soluble sugar in dry mass, and drought tolerance, is a promising biomass for ethanol production. The overall goals of this study are to develop an efficient approach to convert PS sorghum to ethanol and to understand the structural characteristics of biomass. For increasing the efficiency of biomass conversion, an integrated method, using diluted sulfuric acid pretreatment, has been developed to utilize both the structural polysaccharide (cellulose) and the soluble sugar (sucrose, glucose, and fructose) for fermentation. Response surface methodology was employed to optimize the pretreatment condition for maximizing the cellulose-glucose conversion. Simultaneous enzymatic hydrolysis and yeast fermentation was used for ethanol production. The effects of the buffer concentration, the inoculation dosage and time, and the fermentation temperature were investigated for maximizing ethanol yield. A total conversion efficiency of 77.2% and an ethanol concentration of 2.3% (v/v) were obtained after 72 h fermentation. About 210 kg (~266 Liters) ethanol could be produced from one ton dry mass of PS sorghum under the optimized condition. The structural features of the PS sorghum were studied using techniques including scanning electron microscopy and X-ray diffraction/scattering. Biomass at different botanic locations was investigated. Wide-angle X-ray diffraction (WAXD) study showed that the PS sorghum rind had oriented crystal peaks and the highest degree of crystallinity, whereas the crystalline structures of the inner pith and leaf were less ordered. The results from WAXD suggested that crystalline cellulose was melted at 120 °C before its significant degradation. Both the cellulose crystallinity and the crystal size at the dimension lateral to fiber direction increased as the temperature increased from 120 to 160 °C. The efficiency of enzymatic hydrolysis increased because the protective structure was damaged and most hemicellulose was removed, resulting in the increase in accessible area as suggested by small-angle X-ray scattering result of the increased length of microvoids. The results from WAXD also suggested a simultaneous hydrolysis and crystallization of cellulose by acid.
Chenevert, Blake Charles. "Fine ash morphology and aerosol formation : a comparison of coal and biomass fuels /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/7094.
Повний текст джерелаWong, Ka In. "Machine-learning-based modeling of biofuel engine systems with applications to optimization and control of engine performance." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691886.
Повний текст джерелаKanchanalai, Pakkapol. "New dehydration and pretreatment process for ethanol production from biomass." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53559.
Повний текст джерелаEmer, Beatrice. "Optimization of wood energy plant supply." Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3426562.
Повний текст джерелаIn questi anni il crescente interesse all’utilizzo di fonti energetiche rinnovabili in sostituzione a fonti energetiche fossili è stato determinato dalla consapevolezza della necessità di salvaguardare l’ambiente e di comportarsi in maniera sostenibile. Tra le varie fonti energetiche rinnovabili, le biomasse legnose svolgono un ruolo importante, grazie alla loro locale ed omogenea distribuzione. L’utilizzo di biomasse legnose permette la riduzione delle emissioni di gas serra, l’utilizzo di risorse locali disponibili e sostenibili, la riduzione della dipendenza riguardo alle importazioni di energia, la maggior sicurezza dell’approvvigionamento di combustibili, il rispetto degli impegni assunti nel corso della Conferenza Internazionale di Kyoto. Inoltre l’utilizzo delle biomasse legnose forestali favorisce l’incremento delle attività, introiti ed occupazione nelle aree rurali. Per una corretta progettazione di un impianto è essenziale fare un’indagine sulla presenza di risorse disponibili sul territorio. La valutazione e la conoscenza della disponibilità di materia prima a livello locale e la logistica dell’approvvigionamento sono essenziali per evitare una competizione intrasettoriale e l’importazione di biocombustibili da altre regioni o stati. Quando si pianifica la posizione adatta per impianti o centri di stoccaggio è essenziale considerare l’uso attuale del territorio, la legislazione vigente e aspetti sociali ed economici. Nella catena di approvvigionamento di biomasse legnose le operazioni di trasporto sono quelle che, a parità di tipologia di materia prima, maggiormente determinano la differenza di costo. Ottimizzare i trasporti significa utilizzare il minor sforzo di trasporto possibile per soddisfare una domanda di combustibile con le risorse disponibili. I trasporti possono essere minimizzati utilizzando in maniera ottimale la capacità di carico dei mezzi di trasporto e scegliendo la strada più corta verso la destinazione finale. Le alternative di approvvigionamento che minimizzano i trasporti privilegiando le risorse di combustibile locali sono maggiormente sostenibili anche da un punto di vista socio-economico. Lo studio e l’ottimizzazione dell’approvvigionamento in piccole realtà locali, o anche a grande scala, può essere un valido strumento di supporto alle decisioni che il gestore di un impianto deve intraprendere per assicurare il funzionamento dell’impianto stesso e minimizzare i costi. All’interno di questo lavoro di ricerca è stata realizzata una metodologia che combina l’utilizzo della programmazione lineare con i sistemi informativi geografici. Nello studio sono state prese in considerazione diverse modalità di approvvigionamento per le differenti tipologie di materiale disponibile sul territorio. Per il cippato forestale sono stati considerate tutte le fasi e relativi costi di approvvigionamento da bordo strada all’impianto. Per conoscere offerta e domanda di combustibile, sono state raccolte informazioni sulle fonti e sulla destinazione del combustibile attraverso interviste e attingendo a banche dati. Attraverso una elaborazione di “network analysis” effettuata con gli strumenti GIS, sono stati individuati i costi di trasporto da ogni fonte di biomassa (bosco o segherie) fino alle potenziali destinazioni. Nella programmazione lineare sono stati presi in considerazione le limitazioni di disponibilità di combustibile, i costi di approvvigionamento e le capacità massime delle varie fasi delle catene di approvvigionamento per soddisfare la domanda di energia degli impianti. Il risultato dell’elaborazione eseguita con il software “LINGO” evidenzia le destinazioni ottimali del combustibile, che vengono poi visualizzate su mappe in GIS. La metodologia è stata applicata allo studio dell’ottimizzazione dell’approvvigionamento di due impianti termici a cippato situati in Val di Fiemme (Provincia di Trento). E’ stato simulato l’approvvigionamento di biomassa nel corso di un decennio con materiale proveniente da scarti di imprese di prima lavorazione del legno e da residui delle utilizzazioni forestali. Un’altra simulazione ha riguardato lo studio dell’approvvigionamento di cippato, nel corso di un anno e su scala bimestrale, in base alla domanda stagionale da parte degli impianti e alla disponibilità di residui nel corso dei periodi temporali considerati. In questo ultimo studio è stata considerata anche la possibilità di utilizzare un centro di stoccaggio del materiale. Sono state testate tre localizzazioni del centro di stoccaggio allo scopo di verificare la posizione più strategica, dal punto di vista economico. L’andamento dell’essicazione del materiale stoccato e dell’incremento della sua densità energetica è stato modellizzato dopo essere stato studiato con prove in campo. Alcune analisi di sensitività sono state realizzate allo scopo di verificare l’influenza dei diversi parametri considerati dal modello sul risultato finale. La metodologia applicata può essere utilizzata come strumento per decidere la localizzazione ottimale di impianti o centri di stoccaggio del materiale nel corso della loro progettazione. Una metodologia simile, per studiare l’approvvigionamento di materiale su grande scala, è stata applicata nella regione della Finlandia Centrale in particolare per rifornire una centrale e una bioraffineria. I due impianti presi in esame hanno una domanda elevata di combustibile e quindi con una forte competizione per le materie prime. L’ottimizzazione dell’utilizzo delle risorse evidenzia le aree di destinazione delle varie forme di biomassa disponibile. Ponendo dei limiti di disponibilità a pagare da parte di un impianto, si vuole studiare l’effetto sull’area di approvvigionamento. Nell’ottimizzazione dell’approvvigionamento nei dieci anni, la tipologia di approvvigionamento ottimale è la cippatura a bordo strada o in bosco ed il trasporto di materiale cippato all’impianto. Il cippato rimasto ad essiccare un anno è preferito, in quanto ha più elevato contenuto energetico. Per quanto riguarda lo studio dell’ottimale localizzazione di un centro di stoccaggio, tra le tre localizzazioni del terminal non si registrano differenze significative in termini di costo totale di approvvigionamento. Questo può essere dovuto alla piccola scala dell’area considerata. Inoltre ulteriori limitazioni sui volumi di trasporto dovrebbero essere prese in considerazione, magari adottando variabili binarie al posto di variabili continue. Per quanto riguarda le analisi di sensitività, la più utile anche dal punto di vista della logistica è quella del volume di trasporto di combustibile. Aumentando la capacità di trasporto dell’autocarro trasportante residui non cippati, questa modalità di approvvigionamento viene preferita. Diminuendo il contenuto idrico il cippato forestale è preferito a quello di segheria. Ne caso finlandese preso in esame, la modalità di approvvigionamento ottimale risulta essere per entrambi gli impianti l’utilizzo di residui forestali trasportati tal quali fino a una distanza di 60 km e imballati per distanze maggiori. Ponendo limitazioni sulla disponibilità a pagare da parte di un impianto, l’altro ne trae vantaggio in quanto si approvvigiona da un’area più vicina. Il modello matematico che è stato sviluppato, attraverso la programmazione lineare ed in particolare il “problema dei trasporti”, ricalca la problematica di approvvigionamento da risolvere. Un modello così sviluppato può fornire soluzioni più flessibili rispetto alla semplice pianificazione manuale e allo stesso tempo permette di testare diverse strategie e diversi possibile scenari. Grazie all’utilizzo del GIS è possibile visualizzare chiaramente da un punto di vista geografico le soluzioni ottenute, altrimenti consultabili leggendo una lista di numeri difficilmente comprensibile. L’utilizzo della programmazione lineare assieme ai sistemi informativi geografici sono un utile metodo per determinare la migliore localizzazione di strutture o l’approvvigionamento ottimale di materie prime. Le diverse analisi di sensitività permettono di capire i fattori che maggiormente influenzano la logistica dell’approvvigionamento.
Stockenreiter, Maria [Verfasser], and Herwig [Akademischer Betreuer] Stibor. "Ecological optimization of biomass and lipid production by microalgae / Maria Stockenreiter. Betreuer: Herwig Stibor." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1026211298/34.
Повний текст джерелаOYEKALE, JOSEPH OYETOLA. "Modelling, thermoeconomic analysis and optimization of hybrid solar-biomass organic Rankine cycle power plants." Doctoral thesis, Università degli Studi di Cagliari, 2020. http://hdl.handle.net/11584/284453.
Повний текст джерелаCapes, Gerard. "Aging of biomass burning aerosols and formation of secondary organic aerosols over West Africa." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498784.
Повний текст джерелаAlvarado, Matthew James. "Formation of ozone and growth of aerosols in young smoke plumes from biomass burning." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45606.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 272-291).
The combustion of biomass is a major source of atmospheric trace gases and aerosols. Regional and global-scale models of atmospheric chemistry and climate take estimates for these emissions and arbitrarily "mix" them into grid boxes with horizontal scales of 10-200 km. This procedure ignores the complex non-linear chemical and physical transformations that take place in the highly concentrated environment of the young smoke plumes. In addition, the observations of the smoke plume from the Timbavati savannah fire [Hobbs et al., 2003] show much higher concentrations of ozone and secondary aerosol matter (nitrate, sulfate, and organic carbon [OC]) in the smoke plume than are predicted by current atmospheric chemistry models. To address these issues, we developed a new model of the gas- and aerosol-phase chemistry of biomass burning smoke plumes called ASP (Aerosol Simulation Program). Here we use ASP to simulate the gas-phase chemistry and particle dynamics of young biomass burning smoke plumes and to estimate the errors introduced by the artificial mixing of biomass burning emissions into large-scale grid boxes. This work is the first known attempt to simultaneously simulate the dynamics, gas-phase chemistry, aerosol-phase chemistry, and radiative transfer in a young biomass burning smoke plume. We simulated smoke plumes from three fires using ASP combined with a Lagrangian parcel model. We found that our model explained the formation of ozone in the Otavi and Alaska plumes fairly well but that our initial model simulation of the Timbavati smoke plume underestimated the formation of ozone and secondary aerosol matter. The initial model simulation for Timbavati appears to be missing a source of OH. Heterogeneous reactions of NO2 and SO2 could explain the high concentrations of OH and the rapid formation of ozone, nitrate and sulfate in the smoke plume if the uptake coefficients on smoke aerosols are large [O(10-3) and O(10-4), respectively]. Uncharacterized organic species in the smoke plume were likely responsible for the rapid formation of aerosol OC. The changes in the aerosol size distribution in our model simulations were dominated by plume dilution and condensational growth, with coagulation and nucleation having only a minor effect.
(cont.) We used ASP and a 3D Eulerian model to simulate the Timbavati smoke plume. We ran two test cases. In the reference chemistry case, the uncharacterized organic species were assumed to be unreactive and heterogeneous chemistry was not included. In the expanded chemistry case, the uncharacterized organic compounds were included, as were heterogeneous reactions of NO2 and SO2 with uptake coefficients of 10-3 and 2x10-4, respectively. The 3D Eulerian model matched the observed plume injection height, but required a large minimum horizontal diffusion coefficient to match the observed horizontal dispersion of the plume. Smoke aerosols reduced the modeled photolysis rates within and beneath the plume by 10%-20%. The expanded chemistry case provided a better match with observations of ozone, OH, and secondary aerosol matter than the reference chemistry case, but still underestimated the observed concentrations. We find that direct measurements of OH in the young smoke plumes would be the best way to determine if heterogeneous production of HONO from NO2 is taking place, and that these measurements should be a priority for future field campaigns. Using ASP within an Eulerian box model to evaluate the errors that can be caused by the automatic dilution of biomass burning emissions into global model grid boxes, we found that even if the chemical models for smoke plume chemistry are improved, the automatic dilution of smoke plume emissions in global models could result in large errors in predicted concentrations of O3, NOx and aerosol species downwind of biomass burning sources. The thesis discusses several potential approaches that could reduce these errors, such as the use of higher resolution grids over regions of intense biomass burning, the use of a plume-in-grid model, or the use of a computationally- efficient parameterization of a 3D Eulerian plume chemistry model.
by Matthew James Alvarado.
Ph.D.
Gao, Qiuju. "Dioxins and dioxin-like compounds in thermochemical conversion of biomass : formation, distribution and fingerprints." Doctoral thesis, Umeå universitet, Kemiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-118861.
Повний текст джерелаHe, Hanbing. "Layer Formation on Bed Particles during Fluidized Bed Combustion and Gasification of Woody Biomass." Doctoral thesis, Luleå tekniska universitet, Energivetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63090.
Повний текст джерелаSchnably, Jamie. "Soil characterization, classification, and biomass accumulation in the Otter Creek Wilderness." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=3215.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains vii, 137 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 71-76).
Ramachandran, Rahul. "Design of Tactical and Operational Decisions for Biomass Feedstock Logistics Chain." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71776.
Повний текст джерелаMaster of Science
Ravula, Poorna Pradeep. "Design, Simulation, Analysis and Optimization of Transportation System for a Biomass to Ethanol Conversion Plant." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/27572.
Повний текст джерелаPh. D.
Cambero, Calva Claudia Adrileth. "Economic, environmental and social optimization of forest-based biomass supply chains for bioenergy and biofuels." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58166.
Повний текст джерелаForestry, Faculty of
Graduate
Ellens, Cody James. "Design, optimization and evaluation of a free-fall biomass fast pyrolysis reactor and its products." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1473200.
Повний текст джерелаSridhar, Rajesh. "Chemistry models for major gas species estimation and tar prediction in fluidized bed biomass gasification." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104564.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 133-140).
The present work deals with the process of fluidized bed biomass gasification (FBBG), which is the thermochemical conversion of solid biomass into combustible synthetic gas using a fluidized bed. Fluidized bed gasifiers encounter high tar concentrations at the gasifier outlet necessitating expensive downstream cleaning equipment. Apart from the complex chemical pathways involved, tar production is also strongly dependent on the transport processes occurring inside the gasifier. Hence, the development of a detailed model to predict the variation of tar production under different operating conditions needs to include two important considerations: a comprehensive chemical kinetic sub-model and a detailed hydrodynamic sub-model. However, due to the huge computational expense associated with such a detailed simulation coupling the complex chemistry and hydrodynamics, there is a need to develop simplified models on both fronts. The first part of this work presents a detailed discussion on the chemistry models for biomass gasification: after introducing the existing state-of-the-art reaction mechanisms (both detailed and compact), two new global chemistry models, incorporating a global primary tar cracking reaction, for air-blown gasification and steam-blown gasification conditions are developed. The major gas species and total tar concentrations predicted using the global models in reactor network simulations of the gasifiers are compared with the corresponding predictions obtained using the detailed CRECK mechanism for biomass gasification, as well as with the available experimental observations. On the hydrodynamics front, an improved reactor network model based on the two-phase theory has been developed to better capture the mixing inhomogeneities in the bubbling fluidized bed, including mass transfer considerations between the bubble and emulsion phases. Finally, the predictions of various tar class concentrations and major gas species concentrations, obtained using the improved reactor network model in conjunction with the detailed CRECK kinetic reaction mechanism, for both air-blown gasification and steam gasification, are presented. Key words: Biomass gasification, Fluidized beds, Chemical reactor network modeling, chemical kinetics, chemistry mechanism reduction, Global chemistry model
by Rajesh Sridhar.
S.M.
Mermelstein, Joshua. "The impact and mitigation of carbon formation on SOFC anodes arising from biomass gasification tars." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511811.
Повний текст джерелаFagerström, Jonathan. "Fine particle emissions and slag formation in fixed-bed biomass combustion : aspects of fuel engineering." Doctoral thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-102687.
Повний текст джерелаGunarathne, Duleeka. "Optimization of the performance ofdown-draft biomass gasifier installedat National Engineering Research &Development (NERD) Centre ofSri Lanka." Thesis, KTH, Kraft- och värmeteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-78994.
Повний текст джерелаHindersin, Stefan Verfasser], and Dieter [Akademischer Betreuer] [Hanelt. "Photosynthetic efficiency of microalgae and optimization of biomass production in photobioreactors / Stefan Hindersin. Betreuer: Dieter Hanelt." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2013. http://d-nb.info/1032313196/34.
Повний текст джерелаKarlsson, Emma, and Sandra Widen. "The possibility of an increased utilization of harvested biomass in Östergötland: Optimization and analysis of flows." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-150141.
Повний текст джерелаSjöde, Anders. "Chemical characterization in the biorefinery of lignocellulose : formation and management of oxalic acid and analysis of feedstocks for bioethanol production /." Karlstad : Faculty of Technology and Science, Chemistry, Karlstad University, 2008. http://www.diva-portal.org/kau/abstract.xsql?dbid=1362.
Повний текст джерелаMellin, Pelle. "Pyrolysis of biomass in fluidized-beds: in-situ formation of products and their applications for ironmaking." Doctoral thesis, KTH, Energi- och ugnsteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-172293.
Повний текст джерелаJärn och stålindustrin stod för 8 % av alla koldioxidutsläpp i Sverige, 2011. Alternativa energibärare undersöks i denna avhandling. Genom pyrolys av biomassa, fås en energirik fast produkt, och samtidigt en gasformig och en vätskeformig produkt (bio-olja). Om en fluidbäddsreaktor används kan största möjliga mervärde tillföras de kombinerade produkterna. Djupare förståelse för pyrolys i fluidbäddar har eftersträvats med hjälp fluiddynamikberäkningar (CFD) och detaljerade kinetikscheman. Den fasta produkten har undersökts som bio-injektion i masugnar. En ny approach för modellering av primär och sekundär pyrolys separat, har utvecklats i denna avhandling. En biomassapartikel avflyktigas under pyrolys. Primär pyrolys är nedrytningen av den fasta biomassan till intermediärer (flyktiga ämnen) som kan lämna partikeln. Sekundärpyrolys är nedbrytning av dessa flyktiga ämnen, som primärt sker i gasfas. Primärpyrolysen (i detta arbete, 35 ämnen och 15 reaktioner) sker mestadels i bäddzonen och därmed behöver modellen ta hänsyn till den komplexa fysiska interaktionen av biomassapartiklarna med fluidbäddsmediet (sand) och fluidiseringsgasen. Detta åstadkoms med hjälp av Euleriska faser och interaktionstermer, samt en lösare för hantering av styva reaktionssystem. Sekundärpyrolysen sker huvudsakligen utanför bäddzonen. Fluiddynamiken är enklare men kemin är mer komplex, med fler ämnen närvarande. Att tidseffektivt köra beräkningarna, för sekundärpyrolysen (134 ämnen, 4169 reaktioner) åstadkoms med hjälp Dimensionsreducering, Kemiagglomerering och In-situtabulering (ISAT); som implementerats i en sannolikhetstäthetsfunktion (PDF). En analys av de numeriska beräkningarna antyder att de kan matchas med experimentella resultat, med avseende på tryckprofil, temperaturprofil, utbyte av gasformiga, fasta och vätskeformiga produkter. Dessutom, med några undantag, kan beräkningarna matchas ganska väl med de viktigaste gasformiga produkterna. Därmed kan de huvudsakliga fysiska och kemikaliska mekanismerna representeras av modellen men förbättringar är givetvis möjliga. En parameterstudie av reaktionsatmosfärer (dvs fluidiseringsgaser) genomfördes, för att förstå processen bättre. Modellen visade på betydande effekter av atmosfären, fysisk (både under primär och sekundärpyrolys), och kemiskt (under sekundärpyrolysen). Under primärpyrolysen undersöktes den fysiska inverkan av reaktionsatmosfärer (N2, H2O). När ånga jämfördes med kvävgas, visade det sig att värmeflödet sker mer homogent på både bäddnivå och på partikelnivå, med ångatmosfär. Under sekundärpyrolysen, så antyder resultaten på att turbulensinteraktion spelar en viktig roll för accelererad oönskad sekundärpyrolys av de vätskebildande ämnena. Ånga som är en av de undersökta atmosfärerna (N2, H2O, H2, CO, CO2), resulterade i den lägsta omfattningen av sekundärpyrolys. Dock så ledde en ångatmosfär varken till den lägsta residenstiden, den lägsta peaktemperaturen eller den lägsta radikalkoncentrationen; som alla normalt motverkar sekundärpyrolysen. Ett repeterat case, med hög turbulens i inloppet, gav betydande sekundärpyrolys av de vätskebildande ämnena. Attraktiviteten av approachen är given men mer testning och utveckling behövs, som också påkallats av andra forskare. Den fasta produkten efter pyrolys kallas träkol. Angående dess applicering i masugnar, så visar modelleringsresultaten att full substitution av fossilt kol går att göra. Betydande minskningar i koldioxidutsläpp är därmed möjliga. Energibesparingar är dessutom möjligt, tack vare det höga syreinnehållet i träkol (och biobränslen generellt), vilket ger större volymer av masugnsgas med högre värmevärde (och mindre sensibel värme som inte är utvinnbar). Energibesparingar är möjliga även om hänsyn tas till högre eleffekt för syrgasanrikning i blästerluften och en högre injektionsåtgång på energibasis. En översikt över biomassatillgången och existerande teknikleverantörer i Sverige, indikerar att all injektion i Masugn 3 (i Luleå) kan ersättas med biomassa. Baserat på statistik från 2008, så kan ersatt kol med träkol, minska de platsspecifika koldioxidutsläppen med 28.1 % (eller 17.3 % av alla utsläpp från stålindustrin). Som jämförelse kan torrifierad biomassa and obehandlad biomassa reducera utsläppen med 6.4 % respektive 5.7 %.
QC 20150827
Eghtesad, Masoumeh. "Optimization of magnesium removal from hydrometallurgical leach liquors by struvite formation." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58789.
Повний текст джерелаApplied Science, Faculty of
Materials Engineering, Department of
Graduate
Akhtari, Shaghaygh. "Economic assessment and optimization of forest biomass supply chain for heat generation in a district heating system." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43697.
Повний текст джерелаDo, Thi Lien, Thi To Uyen Do, Thi Nhi Cong Le, Phuong Ha Hoang, and Thi Ngoc Mai Cung. "Optimization production conditions of photosynthetic purple bacteria biomass at pilot scale to remove sulphide from aquaculture pond." Technische Universität Dresden, 2018. https://tud.qucosa.de/id/qucosa%3A32725.
Повний текст джерелаNhằm mục tiêu xử lý sulphide trong môi trường nuôi trồng thủy sản, chúng tôi đã phân lập và lựa chọn được ba chủng vi khuẩn tía quang hợp có khả năng loại bỏ sulphide cao nhất ký hiệu TH21, QN71, QN52 từ các vùng ven biển Thanh Hóa và Quảng Ninh. Các chủng này đã được định loại và thử nghiệm tại một số ao nuôi thủy sản ở các vùng khác nhau thu được kết quả tốt về chất lượng nước. Để tạo chế phẩm vi khuẩn tía quang hợp từ 3 chủng lựa chọn được ứng dụng rộng rãi và có giá thành phù hợp cho nông hộ, trong nghiên cứu này, chúng tôi nghiên cứu tối ưu hóa các điều kiện sản xuất sinh khối hỗn hợp 3 chủng vi khuẩn tía quang hợp ở quy mô pilot. Kết quả cho thấy đã tìm kiếm được nguồn cơ chất là bột đậu tương (1g/l) và acetate (0.5g/l) là những chất có giá thành thấp, dễ tìm kiếm, thuận tiện trong nhân nuôi ở quy mô lớn. Hỗn hợp vi khuẩn tía quang hợp có thể nuôi trong các bể kính, ở điều kiện vi hiếu khí, có ánh sáng chiếu tự nhiên có thể sản xuất được chế phẩm vi khuẩn tía quang hợp có mật độ cao, cơ chất còn lại sau sản xuất là ít nhất.
Haji, Esmaeili Seyed Ali. "A Market Incentives Analysis of Sustainable Biomass Bioethanol Supply Chains with Carbon Policies." Diss., North Dakota State University, 2020. https://hdl.handle.net/10365/31869.
Повний текст джерелаAkindele, Ojo David. "Influence of additives on agglomeration behaviours/formation in a laboratory-scale fixed bed combustion of biomass fuels." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/20047/.
Повний текст джерелаIglesias, Sergio. "Optimum Spanloads Incorporating Wing Structural Considerations And Formation Flying." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/35718.
Повний текст джерелаFor single aircraft, a discrete vortex method which performs the calculations in the Trefftz plane has been used to calculate optimum spanloads for non-coplanar multi-surface configurations. The method includes constraints for lift coefficient, pitching moment coefficient and wing root bending moment. This wing structural constraint has been introduced such that wing geometry is not changed but the modified load distributions can be related to wing weight. Changes in wing induced drag and weight were converted to aircraft total gross weight and fuel weight benefits, so that optimum spanloads that give maximum take-off gross weight reductions can be found. Results show that a reduction in root bending moment from a lift distribution that gives minimum induced drag leads to more triangular spanloads, where the loads are shifted towards the root, reducing wing weight and increasing induced drag. A slight reduction in root bending moment is always beneficial, since the initial increase in induced drag is very small compared to the wing weight decrease. Total weight benefits were studied for a Boeing 777-200IGW type configuration, obtaining take-off gross weight improvements of about 1% for maximum range missions. When performing economical, reduced-range missions, improvements can almost double. A long range, more aerodynamically driven aircraft like the Boeing 777-200IGW will experience lower benefits as a result of increasing drag. Short to medium range aircraft will profit the most from more triangular lift distributions.
Formation flight configurations can also result in large induced drag reductions for load distributions that deviate from the elliptical one. Optimum spanloads for a group of aircraft flying in an arrow formation were studied using the same discrete vortex method, now under constraints in lift, pitching moment and rolling moment coefficients. It has been shown that large general improvements in induced drag can be obtained when the spanwise and vertical distances between aircraft are small. In certain cases, using our potential flow vortex model, this results in negative (thrust) induced drag on some airplanes in the configuration. The optimum load distributions necessary to achieve these benefits may, however, correspond to a geometry that will produce impractical lift distributions if the aircraft are flying alone. Optimum separation among airplanes in this type of formation is determined by such diverse factors as the ability to generate the required optimum load distributions or the need for collision avoidance.
Master of Science
Weber, Jost. "Optimization methods for the mixture formation and combustion process in Diesel engines /." Göttingen : Cuvillier, 2008. http://d-nb.info/990746488/04.
Повний текст джерелаDance, Michael Raymond Jr. "Hydroxide Formation and Carbon Species Distributions During High-Temperature Kraft Black Liquor Gasification." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7189.
Повний текст джерела