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1
Hart, J. "Separation of gases by adsorption." Thesis, University of Bath, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234617.
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Lin, Lin. "Numerical simulation of pressure swing adsorption process." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24184.pdf.
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Burnett, Hannelene Jo-Anne. "Equilibrium shift of gold adsorption in a batch reactor." Thesis, Cape Technikon, 2001. http://hdl.handle.net/20.500.11838/881.
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Thesis (MTech(Chemical engineering))--Cape Technikon, Cape Town, 2001Over the years the carbon-in-pulp technology has been refined to become the highly efficient process that is used in our present-day system of recovering dissolved gold from cyanide leached pulps. The efficiency of a CIP circuit mainly depends on the effectiveness ofthe adsorption section as it not only determines the amount of soluble gold lost in the residues, but also indirectly affects the function of the other processes in the plant. Research in this area has declined over the past few years as a result of a decrease in the gold price. It is now more than ever important to investigate the operating conditions ofthe adsorption process to ensure that a highly effective system is maintained.The adsorption of gold cyanide onto activated carbon is to a large extent dependent on maintaining operating conditions well above those of equilibrium. The Freundlich and the Langmuir isotherms have been used by many researchers to describe the equilibrium conditions of the adsorption process. The general practice in the carbonin- pulp technology is to use an isotherm for the prediction of a circuit's performance. As confidence has increased in the reliability of these predictions, it has become important to acquire knowledge of the equilibrium condition that is driving the process. Previous research findings have indicated that the equilibrium isotherm of gold cyanide adsorption onto activated carbon is influenced by changes in the adsorption conditions down the adsorption train. This equilibrium or isotherm shift may lead to errors in the prediction of gold adsorption rates, which results in the filct that the simulations of the performance of the CIP circuits are not reliable. In this study the aim was to investigate the combined influence of various operating conditions on the adsorption equilibrium
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Dastoli, Giovanni. "Mass Transfer in Nitrogen Pressure Swing Adsorption Plants: a Custom Model Based on Aspen Adsorption." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
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In this work, a dynamic mathematical model was developed for the simulation of the pressure swing adsorption process (PSA), through the Aspen Adsorption software for the purpose of validation, optimisation, and control of the nitrogen generation in the PSA pilot plant located at the Fachhochschule Münster (Münster University of Applied Sciences), Faculty of Chemical Engineering - Steinfurt. The mathematical model for the description of the transport phenomena developed within the packed column filled by adsorbent material (CMS) was formulated through the application of several assumptions in the mass/momentum and energy balances, in order to generate inside the software a correct set of partial differential equations. Simulation studies were performed to investigate the effect of changing various process variables such as the duration of PSA cycle time, the heat effect, and pressure drop, in order to achieve higher purity (up to 10 ppm of residual oxygen). A comparison between simulation results of a dynamic model and experimental results were carried out to evaluate selected assumptions. The outcome showed that the model is reliable in some purity intervals while it is not entirely satisfactory when high purity is required (99.999 % nitrogen) because data for a detailed description of kinetics or transport phenomena are missing. Other possible reasons and future improvements were discussed at the end of this work.
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Zone, Ian Robert. "Dynamics and control of a pressure swing adsorption process." Thesis, University of Surrey, 1998. http://epubs.surrey.ac.uk/762/.
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Gray, Diane Elizabeth. "A quantitative study into carbon-in-pulp adsorption operations." Thesis, Cape Technikon, 1999. http://hdl.handle.net/20.500.11838/886.
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Thesis (MTech (Chemical Engineering))--Cape Technikon, Cape Town, 1999Carbon-in-pulp (CIP) and carbon-in-leach (CIL) remain the most effective, and widely used processes for gold recovery from cyanided pulps. The extensive use of carbon in such processes have prompted many researchers to investigate the mechanism of metal cyanide adsorption. Not only has this provided many viable theories in the understanding of the mechanism, but it has also led to an improved understanding of the effects of the various operating conditions on the CIP circuit. However, the declining gold price has made gold producers aware of the need to either further optimise existing circuits or find alternative means of operation so as to improve efficiency. It is therefore the aim of this study to investigate the factors which influence the metal extraction circuit. In this study the effects of parameters such as gold and carbon concentrations, slurry density and stirring speed on the adsorption process were investigated. It was found that the effects of gold and carbon concentrations could be determined directly, that is, a definite linear relationship exists between these two parameters and adsorption rate. However, slurry density and stirring speed (power input) have a twofold effect on the process. For this reason two distinct terms called the "blinding" and "mixing" numbers have been identified. It has been shown that all the parameters investigated influences the rate of adsorption during the constant rate adsorption period. However, only solution concentration, carbon concentration and carbon loading influence the process during the diminishing rate of adsorption. This confirmed the belief that intraparticle diffusion is the rate controlling factor during the diminishing rate period. Furthermore, the point at which constant rate adsorption is replaced by the diminishing rate of adsorption is mainly a function of solution concentration.
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Terdkiatburana, Thanet. "Simultaneous removal process for humic acids and metal ions by adsorption." Curtin University of Technology, Dept. of Chemical Engineering, 2007. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=18564.
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Humic substances are macromolecules that naturally occur in all environments in which vegetation matter are present. In general, humic acid is part of humic substances which form the major fraction of the dissolved organic matters in surface water and represents 90% of dissolved organic carbon. Humic acid plays a fundamental role in many ecosystems since it interacts with toxic metal ions present in the system, resulting in a decrease in the bio-availability of such ions. Moreover, the availability of humic acid in water can react with other chemical compounds, such as chlorine to form trihalomethanes (including chloroform) and causes an increasing risk of cancer and may be linked to heart, lung, kidney, liver, and central nervous system damage. Therefore, humic acid removal in water treatment processes is very important in order to achieve the drinking water standards. Heavy metals are significant contaminants in aqueous system. All heavy metals can produce toxicity when ingested in sufficient quantities, but there are several important ones such as lead, mercury, copper, cadmium, arsenic, nickel and silver. These heavy metals are so pervasive and produce toxicity at low concentrations. Moreover, they may build up in biological systems and become a significant health hazard.Adsorption is approved as an effective and simple method for water and wastewater treatment process. Many adsorbents then are developed for use in adsorption process such as montmorillonite, peat, activated carbon, etc. In this research, humic acid and heavy metals were mainly selected for adsorption study. In the sorption experiment, several adsorbents such as synthesised zeolite (SZ), natural zeolite (NZ), powdered activated carbon (PAC) and fly ash (FA), were selected to examine the application of HA and heavy metals both in individual and simultaneous adsorption, The characteristics and interactions of the adsorbents with HA and heavy metals were systematically studied by batch laboratory experiments. In the beginning, the adsorption of HA onto SZ, NZ, PAC and FA was investigated and their adsorption capacity was compared. The equilibrium adsorption of HA on SZ, NZ, PAC and FA was found to be 84.1, 67.8, 81.2 and 34.1 mg/g, respectively, at 30 oC and pH 5.0. Dynamic adsorption data show that these adsorbents could reach their adsorption equilibrium after 50 hours. From pH analysis, HA adsorption is favoured at low pH and an increase in pH will lead to the reduction of HA adsorption. SZ and NZ adsorption capacity were affected by the changing of solution temperature; however, in PAC and FA sorption study, there was no significant effect observed. Two heavy metal ions (Cu, Pb) removal by the adsorbents was then conducted. The results showed that the equilibrium sorption capacity of Cu and Pb ions on SZ, NZ, PAC and FA were 43.5, 24.2, 19.7, 28.6 and 190.7, 129.0, 76.8 mg/g, respectively at 30 oC and a pH value of 5. The appropriate pH for Cu and Pb removal was found to be 5 and 6. In most dynamic cases, these adsorbents needed at least 50 hours to reach the adsorption equilibrium. Only adsorption on FA required more than 150 hours to reach the equilibrium.
In simultaneous adsorption experiments, the influences of HA and heavy metal concentration (in the range of 10 to 50 mg/L for HA and 10 to 30 mg/l for heavy metals) on the HA-heavy metal complexation were investigated. The results demonstrated that increasing HA concentration mostly affected Cu adsorbed on SZ, FA and PAC and Pb adsorbed on SZ, NZ and PAC. For HA adsorption, the adsorption rate decreased rapidly with increased initial metal ion concentration. Moreover, the adsorption of heavy metals increased with increased heavy metals concentration in the presence of HA. In the presence of heavy metal ions, the order of HA adsorption followed PAC > FA > SZ > NZ. According to the results, the individual and simultaneous adsorption of HA and heavy metals on each adsorbent achieved a different trend. It mainly depended on the adsorption property of both adsorbates (HA and heavy metals) and adsorbents (SZ, NZ, PAC and FA) and also the operation factors such as pH, concentration, temperature and operation time. Even though this experiment could not obtain high adsorption performance, especially in coadsorption, as compared with other adsorbents, the adsorbents in this study represented a higher adsorption capacity and provide the potential for further development.
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Archery, Evelyn. "Simultaneous absorptiometric determination of copper, nickel, iron and cobalt in refinery process streams : potential on-line application /." Link to the online version, 2005. http://hdl.handle.net/10019/957.
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Myburgh, Dirk Petrus. "The treatment of biodiesel wastewater using an integrated electrochemical and adsorption process." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2693.
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Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2018.The production of biodiesel is an energy and water intensive process. The wastewater that is produced during this process is high in concentrations of COD, BOD, FOG and various other contaminants. Since it contains low levels of nutrients, it is difficult to degrade using natural processes such as conventional activated sludge wastewater treatment. The discharge of untreated biodiesel wastewater also raises serious environmental concern. It interferes when remediated with biological processes and results in additional costs during the production of biodiesel when penalties and fines are applied. Conventional treatment processes are not capable of treating contaminants and pollutants in biodiesel to satisfactory concentrations and hence advanced treatment processes are necessary. In this research, a lab scale integrated treatment process was used to investigate the successful reduction of contaminants, in particular COD, BOD and FOG. The integrated treatment process used in this study consisted of three consecutive steps; acidification, electrochemical oxidation and adsorption using chitosan as an adsorbent. The electrochemical oxidation process with IrO2-Ta2O5/Ti anodes was applied to treat biodiesel wastewater. Different operating conditions were tested to establish favourable conditions. The current density applied as well as the concentration of NaCl as the supporting electrolyte greatly affected the process. A NaCl concentration of 0.08M was deemed sufficient, whereas a current density of 1 mA/cm² showed superior performance compared to lower or higher current densities. Adsorption of pollutants in biodiesel wastewater was investigated using Chitosan as the adsorbent. Various chitosan concentrations, initial pH of the wastewater and repetitive adsorption stages were investigated. It was discovered that all three operating conditions greatly affect the performance of the process. The three consecutive adsorption stages using a chitosan concentration of 4.5 g/L at a pH of 2 resulted in the highest pollutant removal. It was observed that the integrated treatment process could reduce COD, BOD and FOG levels by 94%, 86% and 95% respectively. This concludes that the treated effluent complies with local industrial effluent discharge standards, which could be disposed safely without further treatment.
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Liu, Fangfang. "N-Butanol Fermentation and Integrated Recovery Process: Adsorption, Gas Stripping and Pervaporation." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1400277061.
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Yan, Liang. "Tailoring of the activation process of carbonaceous adsorbentsfor improving their adsorption effectiveness." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1396524230.
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Carabante, Ivan. "Study of arsenate adsorption on iron oxide by in situ ATR-FTIR spectroscopy." Licentiate thesis, Luleå tekniska universitet, Industriell miljö- och processteknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26159.
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Stabilization of arsenic contaminated soils by iron oxides has been proposed as a remediation technique to prevent leaching of arsenate into the environment. However, fundamental studies are needed to establish under which conditions the complexes formed are stable. A new method based on ATR-FTIR spectroscopy was adapted to study the adsorption of arsenate species on iron oxides. The measurements required the use of D2O as solvent. The amount of arsenate complexes adsorbed on the iron oxide increased with decreasing pD in the range studied, viz. pD 4-12. Arsenate complexes adsorbed at pD 4 desorbed from the film to some extent as the pD was increased to 8.5 or 12. The stability of arsenate complexes adsorbed on the iron oxide evidently changed with the change in pD, most likely due to the electrostatic repulsion between the negatively charged oxoanion and the more negatively charged iron oxide as the pD increased. From competitive adsorption experiments it was found that arsenate species were more strongly bonded to the iron oxide than phosphate species. Furthermore, it was found that two different phosphate complexes formed on the iron surface at pD 4, one deuterated and the other one de-deuterated. The complexes showed very different stability. The deuterated phosphate complex was desorbed easily from the iron oxide film as arsenate was added to the system whereas the de-deuterated phosphate complex only desorbed slightly from the film upon adding arsenate.This work has increased the fundamental knowledge of the iron oxide/arsenate/phosphate system, which will be of importance for the development of more effective soil remediation techniques.Godkänd; 2009; 20090905 (ivacar); LICENTIATSEMINARIUM Ämnesområde: Kemisk teknologi/Chemical Technology Examinator: Professor Jonas Hedlund, Luleå tekniska universitet Tid: Fredag den 2 oktober 2009 kl 10.00 Plats: C 305, Luleå tekniska universitet
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Blender, Karl Frederik [Verfasser]. "Adsorption Process Development for the Separation of Toxic Gaseous Components / Karl Frederik Blender." Hamburg : Helmut-Schmidt-Universität, Bibliothek, 2020. http://d-nb.info/1211977323/34.
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Yeh, Ruth Yu-Li. "Treatment of dye wastewaters by adsorption with and without the bio-oxidation process." Thesis, University of South Wales, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295273.
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Yang, Yongkui. "Aggregation, adsorption and toxicity of fullerene C60 nanoparticles in the activated sludge process." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/174905.
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Smith, Sheryl Dianna. "The Influence of Water Quality on Arsenic Sorption and Treatment Process Performance." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/33581.
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A new regulation has been proposed that would lower the acceptable level of arsenic in drinking water from the current standard of 50 ppb. Therefore, research into effective arsenic removal treatment is important, especially for hard to treat waters with high concentrations of silica.
The first phase of research was designed to determine if sand ballasted coagulation is a viable means of removing arsenic from drinking water, and if so, to identify the water qualities in which the technology performs best. A jar test protocol was developed and tested on a wide range of waters to compare microsand ballasted coagulation and other coagulation based treatment processes in terms of arsenic removal. Secondary impacts of the microsand process such as residual turbidity, iron, post-treatment membrane filter run length, and TOC removal were also considered as part of this evaluation. Microsand ballasted coagulation provided promising results for many of the simulated groundwater test conditions in which more than 80% of the arsenic regulation costs will be incurred. However, like conventional coagulation/sedimentation, microsand ballasted coagulation performed poorly in waters with high silica and high pH.
Thereafter, a second phase of research more closely examined the kinetic behavior of arsenic sorption to amorphous and granular oxides in the presence of silica and calcium. At pH 8.5, calcium dramatically improved arsenic sorption to amorphous iron hydroxide in the presence of silica over short reaction times, but had no long-term advantage. This result could have considerable applications for treatment in that it suggests water quality controls the required reaction times. Additionally, batch tests indicated that activated alumina granular media was more sensitive to water quality than granular ferric hydroxide; however, calcium eliminated silica interference to arsenic sorption onto activated alumina.Master of Science
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Howells, Stephen Wyn. "An investigation by surface analysis and heteroflocculation studies into the hydrocol paper making process." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299613.
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Van, den Berg Rudolf. "Inhibition of the pregrobbing phenomenon in gold ores." Thesis, Cape Technikon, 2000. http://hdl.handle.net/20.500.11838/907.
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Thesis (MTech (Chemical Engineering))--Cape Technikon, Cape Town, 2000In a typical gold-recovery plant, it is estimated that a substantial amount of the gold in residues may be in the form that is recoverable by cyanidation. The gold in residues can be ascribed broadly to (l) the presence of cyanicides, which consume the cyanide radical and thus inhibit dissolution of gold, (2) refractory gold resulting from coatings on some gold particles, (3) large gold particles incompletely dissolved due to inadequate contact time, (4) unliberated gold as a result of too coarse a milled product, and (5) gold dissolved during leaching, then adsorbed by other minerals or by carbonaceous matter in the pulp. This study focuses on the latter, where dissolved gold is pregrobbed during leaching by adsorbent materials in the ore. The term pregrobbing refers to the active adsorption ofgold from cyanide pregnant solutions by components ofthe ore. It has been suggested that gold already dissolved by cyanide may be adsorbed by other minerals and by carbonaceous matter in the pulp. The presence ofcarbonaceous matter in gold ores presents a two-fold problem namely, the poor release of gold from the carbonaceous matrix and the uptake of dissolved gold by the carbonaceous leach residues. Studies by several other investigators using ores from various parts of the world have similarly shown that the natural carbonaceous matter associated with refractory gold ores often behaves like activated carbon when in contact with aurocyanide solutions. Some debate also exists over the extent to which gold may be adsorbed onto the surfaces of minerals. Different authors have identified that minerals such as' pyrite, copper sulphides, quartz and layered silicates, such as kaolin, phlogopite and ilIite exhibit gold adsorbing properties. Activated carbon was first used as a model pregrobber in batch kinetic adsorption experiments in the presence of a gold selective strong base anion-exchange resin.
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Moran, Aaron A. "A PSA Process for an Oxygen Concentrator." Cleveland State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=csu1407928173.
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Brown, N. W. "Adsorption of organics in wastewater on nyex and electrochemical regeneration : development of a process." Thesis, University of Manchester, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556317.
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The removal of low concentrations of aqueous phase organics using adsorptive techniques has traditionally used high capacity adsorbent materials, for example activated carbons. The drawback of these materials is that regeneration can be costly and complex. An alternative approach reported in this thesis involves the use of a highly conductive material, a graphite intercalation compound (GIC), as an adsorbent. This material, which has been shown to be non-porous with a low surface area, is capable of electrochemical regeneration. This electrochemical regeneration is achieved by the oxidation of the organics in the anodic compartment of a simple, divided cell. In comparison with activated carbons, it has been demonstrated that adsorption is quick, with up to 88% of equilibrium loading being achieved within 2 minutes. 100% electrochemical regeneration can be achieved in a simple divided electrochemical cell with 10 minutes treatment, by passing a charge of 25 C g-1. The efficiency of electrochemical regeneration depends on a range of variables including charge passed, current density, treatment time, electrolyte concentration and composition and the adsorbent bed thickness. Multiple adsorption and regeneration cycles indicate that there is little loss of adsorptive capacity on regeneration. Whilst a number of modes of operation are potentially possible, the m4jority of the work reported in this thesis is based on separate adsorption and electrochemical regeneration. However, some work on a process involving continuous adsorption coupled with continuous and simultaneous electrochemical regeneration is presented. A third design involving continuous adsorption and regeneration within separate zones IN a single unit is given as an area for further research.
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Horn, Carsten. "Downstream processing with affinity chromatography : a study of a continuous process for biospecific adsorption." Thesis, University of South Wales, 1993. https://pure.southwales.ac.uk/en/studentthesis/downstream-processing-with-affinity-chromatography-a-study-of-a-continuous-process-for-biospecific-adsorption(acd33b1a-fed5-47b3-9b01-b389810c1466).html.
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A polymer matrix of hydroxy ethyl methacrylate - ethylene glycol dimethacrylate was synthesised and coupled with the ligand p-aminobenzamidine. Although the adsorbent displayed sufficient affinity towards trypsin, the overall adsorption performance was not satisfactory. Subsequent studies were carried out with a p-aminobenzamidine silica adsorbent, which gave far superior results. Amounts of up to 35 mg of trypsin per g of silica could be adsorbed from a porcine pancreatic extract at buffer conditions of 0.05 M Tris, 0.5 M NaCl, pH 8. Complete elution was achieved with a buffer of 0.1 M acetic acid, pH 3. The system was characterised by fixed bed breakthrough studies of the adsorption, wash and desorption step. A method of data analysis was developed and applied to the experimental results. Axial dispersion could be identified as the predominant 'mass transfer' mechanism. A simulation model was build, based on the data analysis results. The model was verified successfully against the experimental data. Continuous separation experiments were performed with three fluidised beds, namely an adsorption, desorption and wash column, with circulation of solids between the columns. Purities of 83% and 66% were achieved in these runs with complete recovery of trypsin. A continuous process model, also based on the data analysis results and on fluidised bed characteristics, was found to agree fairly well with the experimental data. Simulation experiments were conducted to find the optimum configuration of the process. Best performances with respect to product purity were obtained for an adsorption column height of 3 cm and a wash column height of 4 cm. Step experiments revealed that the process is relatively easy to control if the solid flow rate is chosen as the control parameter.
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Al, Hodali Reyad. "Numerical simulation of an agricultural foodstuffs drying unit using solar energy and adsorption process." Doctoral thesis, Universite Libre de Bruxelles, 1997. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212169.
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Beh, Christopher Chun Keong. "Vacuum swing adsorption process for oxygen enrichment : a study into the dynamics, modelling and control." Monash University, Dept. of Chemical Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/9533.
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Charalambous, Charithea. "Temperature swing adsorption process for carbon dioxide capture, purification and compression directly from atmospheric air." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33311.
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Many reports, scientific papers, patents, and scientific news investigate the feasibility and affordability of direct carbon dioxide capture from the atmospheric air (DAC). Since carbon dioxide (CO2) is extremely diluted in the atmosphere, large volumes of air have to be handled to capture comparable amounts of CO2. Therefore, both the energy consumption and the plant size are expected to be 'prohibitive'. On the other hand, some analyses have shown that DAC is feasible and can become affordable with essential research and development. DAC has been regarded as an optional bridging or a transitional technology for mitigating CO2 emissions in the medium-term. Priorities include investing in renewable and low-carbon technologies, efficiency and integration of energy systems, and realisation of additional environmental benefits. A heavy reliance on negative emission technologies (NETs), and consequently DAC, may be extremely risky as NETs interact with a number of societal challenges, i.e. food, land, water and energy security. Although, "... capturing carbon from thin air may turn out to be our last line of defence, if climate change is as bad as the climate scientists say, and if humanity fails to take the cheaper and more sensible option that may still be available today" MacKay (2009). Certainly, more research is necessary to bring down both cost and energy requirements for DAC. This work firstly predicts the adsorption equilibrium behaviour of a novel temperature swing adsorption process, which captures carbon dioxide directly from the air, concentrates, and purifies it at levels compatible to geological storage. The process consists of an adsorption air contactor, a compression and purification train, which is a series of packed beds reduced in size and connected in-line for the compression and purification purposes, and a final storage bed. The in-line beds undergo subsequent adsorption and desorption states. The final desorbed stream is stored in a storage bed. This cyclic process is repeated for a number of times imposed by the required purity and pressure in the final bed. The process is been thermodynamically verified and optimised. Since, the overall performance of this process does not only depend on the design of the process cycle and operating conditions but also on the chosen adsorbent material, further optimisation of the adsorptive and physical properties of the solid adsorbent is investigated. Thus, the optimal parameters of the potentially used porous materials is identified. Continuing the research on different adsorbent materials, an experimental investigation on the equilibrium properties of two competitive adsorbents is also performed. Besides the thermodynamic analysis, a dynamic model is presented for the investigation of the mass and heat transfer and its influence on the adsorption rate and consequently on the overall process performance. Since the initial stream is very dilute, it is expected that the adsorption rate will be low compared to other temperature swing processes and the capture rate will be affected by the heat transfer. Finally, the design and development of an experimental laboratory-scale apparatus is presented and analysed. Future design improvements are also discussed.
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KUMMARAKUNTLA, VENKATESH. "COLOR REMOVAL OF DYE AND MILK WASTEWATER USING PEANUT HULL BY THE PROCESS OF ADSORPTION." Cleveland State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=csu1530290959626764.
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Pizzochero, Giacomo. "Modelling of the multicomponent thermodynamics and momentum balance of the high-purity N2-PSA-process." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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The nitrogen production and supply processes are continuously improving in terms of efficiency, competitiveness, and cost-effectiveness, encouraged by the growing use and consequent demand in chemical industries. In this work, the PSA pilot plant for nitrogen production located at the Münster University of Applied Sciences, was analysed. The analysis was carried out experimentally in different operating conditions, in order to determine and then improve the performances of the production process. Subsequently, a mathematical model was developed in the ASPEN Adsorption software for the description of the mass transfer phenomena that occur inside the columns packed with the adsorbent material (CMS), which model was formulated by applying various hypotheses and considerations. Material and energy balances were involved, in order to generate the correct set of partial differential equations within the software. A complete representation of pressure drops and thermal effects is the result of this work. The transport phenomena and therefore the component kinetics have been assessed, but a more in-depth analysis is required and indicated at the end of this paper.
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Askari, Hallo Mustafa. "Studies of leaching, recovery and recycling of heavy metals." Thesis, Brunel University, 2008. http://bura.brunel.ac.uk/handle/2438/5087.
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The leachability of cadmium, cobalt, copper, lead, nickel and zinc metals and their oxides, sulfides and carbonates by water, 0.5 mol dm-3 CH3COOH, 0.1 mol dm -3 HCl/NaCI (1: 1 mixture) and 2 mol dm -3 HNO3 is reported. The concentrations of the leached heavy metals are compared with the trigger levels set by World Health Organisation (WHO). Three leaching solutions (nitric, sulfuric and hydrochloric acids) were used to extract copper, zinc, cobalt, nickel, iron and lead from spent catalysts prior to the application of separation technologies. Leaching experiments were conducted using both traditional methods and a microwave-assisted extraction technique. Data are provided on the effects of leaching temperature, leaching time, solid to liquid ratio and acid concentration on the extraction of different metals. The use of 2 mol dm-3 sulfuric acid at 50°C for 60 minutes and at a solid/liquid (S/L) ratio of 1: 25 achieved more than 90% extraction for all the metals studied. A comparison of the results from traditional and microwave extraction techniques demonstrates that microwave heating reduced the time required to obtain maximum metal extraction. The kinetics for the traditional extraction procedure showed that diffusion was the ratecontrolling process, but it was not possible to conclusively establish the rate controlling process for the microwave leaching. The feasibility of using an electrodialysis process to separate metal ions, such as copper from zinc, was examined. A laboratory-scale three compartments membrane system was designed, constructed, used and optimised for the separation process. The separation of copper from zinc in the electrodialysis process exploited the greater stability of the Cu-EDTA complex compared with the Zn-EDTA complex. It was observed that Zn 2+ ions migrated through the cation-exchange membrane from central compartment to catholyte and, simultaneously, the negative Cu-EDTA complex transferred to the analyte compartment crossing the anion exchange membrane. The technique was successfully used to separate mixtures of Cu: Cd and Zn: Ni. The technique could not, however, be used for the separation of Zn from Cd. An adsorption process was used to prepare copper, iron, nickel and zinc oxides catalysts on y-A1203 as support. The materials prepared were used in a fixed bed reactor to assess the catalytic oxidation of volatile organic compounds (methane and ethane) in air. Cu/y- A1203 was found to be the most promising catalyst for the complete oxidation of methane and ethane at temperatures of 575°C and 525°C, respectively. Increasing the calcination temperature in the drying and pre-treatment of the catalysts resulted in a decrease in the catalytic activity.
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Gertenbach, Rosalind May. "Methane and carbon dioxide sorption studies on South African coals." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1919.
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Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2009.Sequestration of carbon dioxide, CO2, has received large interest as a viable option for mitigating the high atmospheric concentrations of this greenhouse gas. Each year 25 gigatons of anthropogenic CO2 (7.3 GtC/yr) are released into the earth’s atmosphere with the combustion of fossil fuels being the major contributing source. Research in the field of sequestration technology involves evaluating various geological structures as possible reservoirs, determining adsorption capacities of natural formations and developing methods for carbon dioxide injection and the monitoring thereof. Identified potential CO2 reservoirs for geological carbon sequestration (GCS) include saline formations, depleted oil and gas fields and deep coal seams. Carbon dioxide sequestration in coal seams provides the economic opportunity of enhanced coalbed methane (CH4) recovery (ECBM). In South Africa, some coal seams are considered a viable option for long term CO2 sequestration projects as they are abundant and closely situated to South Africa’s largest concentrated CO2 point sources. Many studies have been conducted to determine the sorption capacities for methane and carbon dioxide gases on various coals from around the world; however, similar data have not been recorded for South African coals. The objectives of this study are to determine the adsorption capacities for methane and carbon dioxide of three South African coals over a pressure range of 0 – 50 bar. In the study, single-component gas adsorption experiments were conducted and the absolute adsorption capacities are reported. Isothermal adsorption experiments were conducted using both the volumetric and gravimetric methods with the volumetric apparatus pressure range extending up to 50 bar and the gravimetric apparatus up to 20 bar. Carbon dioxide adsorption capacities are much higher than the methane adsorption capacities, which are expected. Gravimetric experiments produce greater adsorption capacities than the volumetric method. However, the relative CO2/CH4 ratios for each coal, as well as the relative CO2/CO2 ratios between coals, remain almost identical. The difference in adsorption capacity is attributed to the strength of the vacuum pump used on each apparatus. The gravimetric apparatus makes use of a much stronger vacuum pump which can thus evacuate the coal pores more adequately than in the volumetric apparatus. The methane and carbon dioxide adsorption capacities of the three moisture-free coals compare well with literature data. The adsorption isotherms fit conventional adsorption models (the Langmuir and Freundlich adsorption equations) extremely well thus indicating that monolayer adsorption takes place. Since no internationally recognised testing standards are in place regarding adsorption procedures on coal, it is very difficult to compare adsorption results presented in the literature. Respective researchers determine their own experimental conditions for the many variables in coal adsorption studies. It is recommended that international testing standards be set in place to make coal research comparable. Such efforts would aid the development of a coal adsorption database, another recommendation, which would advance sequestration technology exchange and eliminate duplication of research efforts. The objectives of the project were achieved by determining the absolute adsorption capacities for carbon dioxide and methane gas of the three South African coals within a pressure range of 0 – 50 bar. Further work is required to investigate adsorption capacities of South African coals under supercritical conditions (above 73 bar abs and 31.1 oC).
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Ohlin, Lindsay. "Adsorption of water, carbon dioxide and methane in zeolite ZSM-5 studied using in-situ ATR-FTIR spectroscopy." Licentiate thesis, Luleå tekniska universitet, Industriell miljö- och processteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17956.
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Global warming is believed to be caused by the extensive emission of greenhouse gases, such as carbon dioxide, into the atmosphere by combustion of fossil fuels, such as coal, oil and natural gas.To reduce the emission of carbon dioxide and hence avoid global warming, alternative fuels derived from renewable resources are desired. Another reason for the worldwide interest in finding alternative fuels is that the reserves of the fossile fuels are limited and the oil and gas resources will eventually run out.Biogas and natural gas are interesting alternatives with no or at least reduced emission of fossil carbon dioxide to the atmosphere as compared to coal and oil. Both gases mainly consist of methane (60–95%) but may also contain a large fraction of carbon dioxide and water. Removal of carbon dioxide and water from biogas and natural gas is of great importance mainly to lower the transportation costs and to increase the heat value of the gas. The most commonly used separation technique is amine absorption. This is an expensive and complex process and alternative techniques are desired. Zeolites are an interesting alternative due to their great potential both as selective adsorbents and membranes. Due to the unique pore structure zeolites are capable of separating species in a mixture based on the molecule size and adsorption properties. Since water, carbon dioxide and methane all have a molecular size smaller than the pore size of the zeolite ZSM-5 studied in the present work, the molecules can enter and adsorb in the pores and hence the separation is based on adsorption rather than size.In the present work, the single component adsorption of water, carbon dioxide and methane in zeolite ZSM-5 was studied using in-situ Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy and the method was successfully further used to study multicomponent adsorption in zeolites.For single gas adsorption experiments, recorded infrared spectra of adsorbed water, carbon dioxide and methane showed characteristic well separated bands for each gas. Adsorbed concentrations of water, carbon dioxide and methane were determined from the recorded infrared spectra. For single gas experiments, the Langmuir model was fitted to the adsorption isotherms and the model matched the experimental data very well. The fitted Langmuir parameters obtained in the present work showed good agreement with values reported in the literature.For multicomponent adsorption experiments, the Ideal Adsorbed Solution Theory (IAST) was used to predict the adsorbed concentrations of water, carbon dioxide and methane using the single component adsorption isotherm parameters as input. The IAST accurately predicted the adsorbed concentrations of both carbon dioxide and methane when adsorbed from binary mixtures. Internary mixtures, also including water, the IAST accurately predicted the adsorbed concentration of methane, however it severely underestimated the adsorbed concentration of carbon dioxide.The latter is probably an effect of a non-ideal behavior of carbon dioxide in the presence of water.The CO2/CH4 adsorption selectivity was determined for various gas compositions and temperatures showing a general increase in the selectivity with decreasing temperature, which is related to the higher heat of adsorption of carbon dioxide. This indicates that the separation of carbon dioxide from biogas and natural gas should be more efficient at lower temperatures. Compared to the literature, the selectivity observed in the present work is relatively high indicating that low silica Na-ZSN-5 may be an effective membrane material.Godkänd; 2013; 20130308 (andbra); Tillkännagivande licentiatseminarium 2013-04-04 Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Lindsay Ohlin Ämne: Kemisk teknologi/Chemical Technology Uppsats: Adsorption of Water, Carbon Dioxide and Methane in Zeolite ZSM-5 Studied Using in-situ ATR-FTIR Spectroscopy Examinator: Bitr professor Mattias Grahn, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Diskutant: Researcher Zoltán Bacsik, Institutionen för material- och miljökemi, Stockholms universitet Tid: Fredag den 26 april 2013 kl 10.30 Plats: F531, Luleå tekniska universitet
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Bentley, Jason A. "Systematic process development by simultaneous modeling and optimization of simulated moving bed chromatography." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47531.
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Adsorption separation processes are extremely important to the chemical industry, especially in the manufacturing of food, pharmaceutical, and fine chemical products. This work addresses three main topics: first, systematic decision-making between rival gas phase adsorption processes for the same separation problem; second, process development for liquid phase simulated moving bed chromatography (SMB); third, accelerated startup for SMB units. All of the work in this thesis uses model-based optimization to answer complicated questions about process selection, process development, and control of transient operation.
It is shown in this thesis that there is a trade-off between productivity and product recovery in the gaseous separation of enantiomers using SMB and pressure swing adsorption (PSA). These processes are considered as rivals for the same separation problem and it is found that each process has a particular advantage that may be exploited depending on the production goals and economics. The processes are compared on a fair basis of equal capitol investment and the same multi-objective optimization problem is solved with equal constraints on the operating parameters.
Secondly, this thesis demonstrates by experiment a systematic algorithm for SMB process development that utilizes dynamic optimization, transient experimental data, and parameter estimation to arrive at optimal operating conditions for a new separation problem in a matter of hours. Comparatively, the conventional process development for SMB relies on careful system characterization using single-column experiments, and manual tuning of operating parameters, that may take days and weeks. The optimal operating conditions that are found by this new method ensure both high purity constraints and optimal productivity are satisfied. The proposed algorithm proceeds until the SMB process is optimized without manual tuning. In some case studies, it is shown with both linear and nonlinear isotherm systems that the optimal performance can be reached in only two changes of operating conditions following the proposed algorithm.
Finally, it is shown experimentally that the startup time for a real SMB unit is significantly reduced by solving model-based startup optimization problems using the SMB model developed from the proposed algorithm. The startup acceleration with purity constraints is shown to be successful at reducing the startup time by about 44%, and it is confirmed that the product purities are maintained during the operation. Significant cost savings in terms of decreased processing time and increased average product concentration can be attained using a relatively simple startup acceleration strategy.
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Ohlin, Lindsay. "An in-situ ATR-FTIR Spectroscopy Study of Adsorption in MFI Zeolites : A step towards effective upgrading of biofuels." Doctoral thesis, Luleå tekniska universitet, Kemiteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16809.
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Global warming is believed to be caused by the extensive emission of greenhouse gases, for example carbon dioxide, into the atmosphere by combustion of fossil fuels, such as coal, oil and natural gas. To reduce the emission of carbon dioxide and hence avoid global warming, alternative fuels derived from renewable resources are desired. Another reason for the worldwide interest in finding alternative fuels is that the reserves of the fossil fuels are limited and the oil and gas sources will eventually run out. Biogas and biobutanol are renewable biofuels which are interesting alternatives to fossil fuels. Biogas is produced during degradation of organic material forming a mixture of mainly methane and carbon dioxide with water as a common trace component. Biobutanol is produced from ABE (acetone, butanol and ethanol) fermentation of biomass. Purification of biogas and biobutanol is essential to increase the heat value of the fuels. Traditional purification processes are energy demanding and expensive. Therefore, other separation processes are currently sought for. Zeolites are promising alternatives due to their great potential both as selective adsorbents and as membranes. Due to the unique pore structure, zeolites are capable of separating components based on their adsorption properties. In the present work, single component adsorption of biogas components such as methane, carbon dioxide and water in zeolite ZSM-5 was studied as well as adsorption of water and butanol in silicalite-1 using in-situ ATR-FTIR spectroscopy. The method was successfully further used to study multicomponent adsorption. For single gas adsorption experiments, recorded infrared spectra of adsorbed methane, carbon dioxide and water showed characteristic, well separated, bands for each gas. Adsorbed concentrations were determined from the recorded infrared spectra. The Langmuir model was fitted to the adsorption isotherms and the model matched the experimental data very well. The fitted Langmuir parameters obtained in the present work was in agreement with values reported in the literature. For multicomponent adsorption experiments, the Ideal Adsorbed Solution Theory (IAST) was used to predict the adsorbed concentrations of methane, carbon dioxide and water using the single component adsorption isotherm parameters as input. In general, the IAST was shown to be a fairly good model for predicting the adsorbed concentrations of methane and carbon dioxide from binary mixtures. For the amount of adsorbed methane from mixtures including water, the IAST predicted the values fairly well. However, for mixtures containing water and carbon dioxide, the IAST could not fully describe the adsorption behavior of the two components. The CO2/CH4 adsorption selectivity was determined for various gas compositions and temperatures showing a general increase in the selectivity with decreasing temperature. This indicates that the separation of carbon dioxide from biogas should be more efficient at lower temperatures. Compared to the literature, the selectivity observed in the present work is relatively high indicating that Na-ZSM-5 may be an effective membrane material for upgrading biogas. Moreover, butanol was preferentially adsorbed over water in silicalite-1, indicating that silicalite-1 may be a promising material for recovery of butanol from dilute water solutions.Godkänd; 2015; 20150325 (linohl); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Lindsay Ohlin Ämne: Kemisk Teknologi /Chemical Technology Avhandling: An in-situ ATR-FTIR Spectroscopy Study of Adsorption in MFI Zeolites Opponent: Professor Niklas Hedin, Avd för materialkemi, Stockholms universitet, Stockholm Ordförande: Biträdande professor Mattias Grahn, Avd för kemiteknik, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet, Luleå Tid: Fredag 29 maj kl 10.15 Plats: C305, Luleå tekniska universitet
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Monpezat, Arnaud. "Développement d’un procédé compact pour le traitement des gaz rares." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1171.
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Dans le cadre du Traité d’Interdiction Complète des Essais nucléaires, le Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA) développe des systèmes de détection des essais nucléaires en se basant sur la mesure des isotopes radioactifs du xénon, tels que le Système de Prélèvement d’Air en Ligne avec l’Analyse des radioXénons. L’adsorption est un procédé adapté pour ce type d’applications mais nécessite l’utilisation de matériaux adsorbants très performants pour piéger et séparer les gaz rares d’intérêt présents dans l’air à l’état de traces. Ce travail doctoral a tout d’abord permis de poser un cadre méthodologique permettant de comparer les matériaux adsorbants disponibles pour séparer le xénon aux faibles pressions partielles et de sélectionner la zéolithe Ag@ZSM-5. De nombreuses techniques ont été employées dont la microscopie électronique à transmission et la simulation ab initio afin d’étudier le vieillissement de ce matériau en conditions procédés, lié aux étapes d’élution en température et aux conditions environnementales, et d’approfondir la connaissance de cet adsorbant. L’influence du support zéolithique sur la formation et la stabilité des particules métalliques, ainsi que l’interaction entre les nanoparticules et le xénon ont en effet été investigués. Finalement la zéolithe Ag@ZSM-5 a été mise en application dans un pilote de laboratoire automatisé. Ce procédé compact de séparation des gaz rares basé uniquement sur des étapes d’adsorption présente des performances encourageantes et permet d’envisager l’utilisation de ce matériau dans des applications variées, de la dépollution de l’air en radon jusqu’à la production industrielle de xénonIn the context of the Comprehensive Nuclear Test Ban Treaty, the Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA) is developing systems to detect nuclear tests based on the xenon radioactive isotopes measurement, such as the Système de Prélèvement d’Air en Ligne avec l’Analyse des radioXénons. Adsorption is a suitable process for this type of application but requires the use of high performance adsorbent materials to trap and separate the rare gases of interest present in the air in trace amounts.In the first instance, this PhD thesis has set a methodological framework to compare the adsorbent materials available to separate xenon at low partial pressures and to select the Ag@ZSM-5 zeolite. Numerous techniques ranging from transmission electron microscopy to ab initio calculation have been employed to study the aging of this material under process conditions, related to the thermal elution steps and environmental conditions. The knowledge of the material has been deepened by studying the influence of zeolite support on the formation and stability of metal particles, as well as the interaction between nanoparticles and xenon. Finally, the Ag@ZSM-5 zeolite was applied in an automated pilot. This compact process for the separation of noble gases based only on adsorption steps shows encouraging performances and allow considering the use of this material in various applications, ranging from decontamination of air polluted by radon to the industrial production of xenon
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Wood, Kevin. "Development of Computational Tools for the Design, Simulation and Optimization of Cyclic Steady State (CSS) Adsorption and Chromatographic Processes." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/72854.
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This dissertation presents an analysis of two aspects of the chromatographic separation process known as Simulated Moving Bed (SMB) chromatography. The first aspect is system design, and the second is improving computer simulations to generate heuristics for choosing operational modes.
For the past 15-20 years, there has been a surge of interest in the use of Simulated Moving Bed systems for the chromatographic separation of chemicals¹. A wide variety of methods, nomenclatures, and conventions have been adopted over the years²⁻⁴, as teams from different backgrounds adopt and improve on the SMB technology. This work presents a unifying discussion of the two major design methods, Triangle Theory and Standing Wave Design, used in the SMB field. We provide the complete computer code required to execute both design methods. A sample problem is worked, which demonstrates the novelty and ease of use that such tools provide. Mathematica was chosen for the implementation of these design methods, because of its strong symbolic analysis capabilities, and simplicity of creating interfaces for new users. We present derivations of the classic Langmuir results in Mathematica, and proceed to extend those implementations. When analytic solutions are impossible, we use Mathematica's numerical methods.
This work also develops a distributed computing tool known as ChromRunner which allows large numbers of detailed numerical simulations to be run simultaneously. The motivations and benefits of this approach are discussed alongside implementation details. We apply the distributed computing system to two separate SMB separations in order to optimize them, as well as determine heuristics governing their operational modes. We wrote ChromRunner in C#, and took advantage of Visual Studio's Entity Framework to create the database backend. The user interface for this software was created using Microsoft's "Windows Presentation Foundation" (WPF) technologies.Ph. D.
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Verdugo, Andrés Verónica. "Studies on As and Sb oxoanions adsorption. Use of mass spectroscopy and synchrotron techniques on process characterisation." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667798.
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Los estudios que se han llevado a cabo en la presente tesis doctoral se basan en el desarrollo de mejoras del proceso de adsorción para la eliminación de oxoaniones, en concreto arsénico y antimonio, por su toxicidad y valor comercial. Las mejoras se centran en la posibilidad de reutilizar el adsorbente (arsénico), y en los métodos sintéticos de adsorbentes que permitan controlar el proceso de adsorción (antimonio). Para ello, se han realizado estudios de adsorción-desorción en discontinuo, de ambos oxoaniones, utilizando un adsorbente comercial polimético, Metalzorb® sponge y su modificación mediante Nanopartículas de Oxidos de Hierro Superparamagnéticos (SPION). Diferentes técnicas analíticas (ICP-MS, espectrofotometría UV-Vis) se han utilizado para obtener la concentración de As y Sb en las disoluciones. Técnicas de microscopía como SEM y TEM se aplicaron para la caracterización de las nanopartículas y diferentes técnicas espectroscópicas (FTIR y XAS) han sido utilizadas para caracterizar el proceso de adsorción y su mecanismo.
La desorción del As se ha llevado acabo mediante la aplicación de un potencial a una solución que contenía el esponja cargada con As(V), para intentar reducirlo a As(III) y con ello conseguir su desorción de la esponja. No ha sido posible llevar a cabo este proceso de reducción sin un reactivo químico que actúe como agente reductor. El uso de electrodos inertes no ha dado resultados favorables. Los mejores resultados se han obtenido con el uso combinado de un electrodo de estaño y una rejilla de acero recubierta de estaño como electrodos de trabajo y contraelectrodo, respectivamente , alcanzando un 60% de eliminación de As. Durante este proceso se observa la formación de un precipitado blanco (compuesto por As y Sn) que indica que el estaño juega un papel clave en este proceso.
En relación con la esponja, se ha desarrollado un nuevo material como adsorbente para la eliminación de Sb. La forma de inmovilizar el SPION en la esponja influye en las propiedades fisicoquímicas del adsorbente y en el proceso de adsorción. Entre las diferentes síntesis evaluadas, la síntesis del SPION directamente sobre la superficie de la esponja presenta las mejores características, ya que favorece la difusión de las nanopartículas en la matriz de la esponja, aumentando la estabilidad del adsorbente y mejorando su capacidad de adsorción. Además, presenta la cinética de adsorción más rápida debido a la presencia de nanopartículas tanto en la superficie como la de pequeñas nanopartículas en el interior (≈ 4.75 nm), aumentando la superficie de contacto entre el SPION de la esponja con la solución de antimonio, y mejorando tanto la cinética de adsorción como el proceso de difusión.
La comparación de este material con la esponja sugiere que ambos materiales son adecuados para la adsorción de Sb (Sb(III) y Sb(V). Sin embargo, la presencia de SPION mejora el proceso. La adsorción del Sb en la esponja esta fuertemente influenciada por el pH, el tiempo de contacto, la concentración inical y la temperatura. Esto, junto a su facil desorción mediante compuestos anionicos y agentes complejantes en solución indica que el Sb(III) y el Sb(V) interaccionan debilmente con la esponja. La presencia del SPION dinminuye la dependencia de la adsorción de Sb de estos factores, lo que junto a su dificil desorción, indica que la interacciona de una forma mas estable con el SPION. Las medidas de XAS y FTIR confirman estos resultados. El Sb(III) y Sb(V) debido a su menor afinidad se absorben en la esponja a traves de puentes de H o interacciones electrostáticas, lo que indica la formación de complejos de esfera externa. La presencia del SPION facilita la formación de enlaces Fe-O-Sb, formádose complejos de esfera interna.The studies that have been carried out in the present PhD thesis Project are based on the development of an improved adsorption process for oxoanions removal, specifically arsenic and antimony due to their toxicity and commercial value. The upgrades are focused on the possibility of adsorbent reuse (As), and on synthetic methods that could endow materials scientists with tools to precisely tailor their structures/pores and have accurate control of adsorption (Sb). For this, adsorption-desorption studies of arsenic and antimony have been performed using a commercial polymeric adsorbent, Metalzorb® sponge, and its modification by SuperParamagnetic Iron Oxide Nanoparticles (SPION). Adsorption-desorption studies will be performed in batch mode. Analytical techniques (ICP-MS, UV-Vis spectrometry) were used to obtain information regarding the Sb and As content in solution. Microscopy techniques (TEM and SEM) were applied to characterise the nanoparticles. Spectroscopic techniques (FTIR and XAS) were used to characterise the adsorption process mechanism. Arsenic desorption process has been performed by applying an electrochemical potential to the solution containing the adsorbent loaded with As(V) to achieve its reduction to As(III) and its desorption from Metalzorb® sponge. This reduction process is not possible without a chemical reagent. The use of inert electrodes does not produce any As(V) reduction. Whereas a combination of Sn and Sn coating on stainless steel mesh as working and counter electrode, respectively, present the best results (60% of As(V) reduction), also forming a white precipitate (As-Sn compound properly characterised), which indicate that Sn plays a key role in As removal. Concerning the Metalzorb® sponge, a new application of enhanced adsorbent material for Sb removal is envisaged. The pathway used for SPION loaded into sponge influences the physicochemical properties of the adsorbent and the sorption process. Among the different synthesis evaluated, direct synthesis shows the best characteristics, producing SPION nanoparticles diffusion inside of the matrix of the sponge, increasing the adsorbent stability and their sorption properties. Furthermore, it is the fastest adsorbent due to the NP placement on the external sponge surface, as well as the presence of smaller NPs (≈ 4.75 nm). There is an increase of the adsorption sites, creating a larger contact area between loaded-SPION/target solution, and enhancing the adsorption kinetics and producing a decrease in the diffusion layer. Comparison of this material with Metalzorb® sponge suggest that both are appropriate adsorbents for antimony (Sb(III) and Sb(V)). However, the presence of SPION improves the removal process enhancing bare sponge adsorption properties. Sb adsorption on the sponge is influenced by pH, contact time, initial concentration and temperature. The strong pH influence, S-type isotherm profiles, the strong effect of interfering anions, and the easy chemical desorption using ionic and complexation stripping agents indicate that Sb(III) and Sb(V) are adsorbed to the sponge by weak interactions. The presence of SPION reduce the pH influence and the influence of interfering anions and shows an L-type isotherm. These evidence, together with almost inexistent desorption with the stripping agent used indicates that Sb(III) and Sb(V) are adsorbed to the sponge+SPION system by strong interactions. XAS and FTIR measurements confirm these results. With a lower affinity, Sb(III) and Sb(V) are absorbed into the bare sponge through H-bonding and electrostatic interaction, which indicates the formation of outer-sphere complexes. The presence of SPION facilitates the formation of the Fe-O-Sb bonds. For Sb(III), adsorption is independent of the pH, indicating that inner-sphere complexes are formed with a partial Sb(III) oxidation (to Sb(V)). On the contrary, Sb(V) adsorption depends on the pH, reducing its sorption capacity up to 40 % when the pH increases from 8 to 9. This pH dependency indicates that inner- and outer-sphere complexes are generated during Sb(V) adsorption.
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Copcutt, Robert Charles. "Modeling of a counter-current adsorption process for removal and recovery of dissolved organics from aqueous effluents." Thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/23191.
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Bukusoglu, Emre. "Dehydration Of Alcohol Solutions Obtained From A Solvent Recovery Process By Pervaporation." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612196/index.pdf.
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Solvent recovery is gaining importance in the chemical production processes to reduce the costs and because of environmental concerns. Therefore separation schemes for recovery and recycle of solvents used in printing and packaging industry were developed. However, a low value by-product, mainly ethyl alcohol and isopropanol, is obtained during the solvent recovery process. If the water concentration of this mixture is decreased below 0.1% by weight, the value of it increases significantly. To dehydrate this stream, a pervaporation-adsorption separation scheme is developed in this study.
The effect of pervaporation process parameters, such as temperature, feed flow rate, permeate side pressure, feed water and ethyl acetate concentration, on the performance of the PERVAP 2211 and 2201 membranes of Sulzer Chem-tech®using the real industrial by-product solution obtained from a local company are investigated. Pervaporation tests were conducted using a home made experimental setup equipped with 148 cm2 rectangular shaped membrane module. Permeates obtained from these experiments were analyzed using a gas chromatograph equipped with FID and the water concentration of the feed solutions were analyzed using Karl-Fisher titration. Besides, adsorption studies were conducted using zeolite 3A in a fixed bed column. As a result of this study, PERVAP 2201 membranes showed higher fluxes with a slightly lower permeate water concentration compared to PERVAP 2211 at the at ranges studied. The increase in the pervaporation performance was observed with an increase in the temperature, permeate side vacuum and feed flow rate over the membrane. Therefore, concentrated-mode experiments were conducted at 70°
C, 2 torr permeate side pressure and 1.6 L/min of feed flow rate using the findings of the parametric studies and the retentate of this experiments were further dehydrated using liquid phase adsorption. Finally, the water concentration of the solution was decreased to 0.04% by weight.
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FELIX, Gutembergue Fernandes. "Análise do processo de dessorção de filme metálico induzido por luz em superfície dielétrica." Universidade Federal de Campina Grande, 2015. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/2147.
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Capes
Nosso trabalho tem como objeto de estudo as interações entre átomos de césio e uma superfície dielétrica. Essas interações são do tipo vanderwaals, atrativas de longo alcance e do tipo Pauli, repulsiva sem curtas distâncias. Este trabalho é composto pela análise do crescimento de filmes térmicos e a análise da dessorção de filmes induzidos por luz. Procuramos compreender: Como é a organização da sobreposição para formar um filme metálico sobre a superfície. Nós apresentamos os procedimentos utilizados e o aparato experimental para medir a dessorção de filmes induzidos por luz. Descrevemos cada procedimento realizado para obtenção das medidas, bem como as etapas de análise dos resultados. Neste trabalho discutimos os modelos mais conhecidos de adsorção, o modelo de Langmuir e o modelo BET.A partir da análise dos dados experimentais de adsorção térmica, constatamos que os dados se ajustam na descrição de filmes que crescem em multicamadas sobre a superfície. Através da análise das curvas de dessorção de filmes induzidos por luz podemos obter valores da energia de adsorção. A principal pergunta que queremos responder é: qual a energia de adsorção para um filme induzido por luz. Os valores obtidos para a energia de adsorção de filmes induzidos por luz (cerca de 0,80 e V) são maiores que as energias de adsorção física (estas em torno de 0,40 e V-0,50 e V) e perto da energia de condensação do césio.
In our work we studied the interactions between cesium atoms and a dielectric surface. These interactions are known as the type Vander Waals attractive at long-range and Pauli type, repulsive ats hort distances. This work is divided in to two parts. In the first part we made the analysis of growth of thermal films and we made in the second partthe analysis of films induced by light. Our objetive is understand how is the organization of atoms to form a metallic film on the surface. We describe the procedures used and the experimental apparat us to measure the desorption of films induced by light. We present how each procedure is performed to obtain the measurements and the results of analysis. In this work we present the best known models for adsorption the Langmuir model and the BET model. By analyzing experimental data of thermal absorption we could observe that the data fits in the description of films that grow in multilayers on the surface. We make the analysis of desorption of films induced by light and we get the adsorption energy values. Our main objective is find the value of the adsorption energy for a film induced by light. The values obtained for the adsorption energy to films induced by light (about 0.80 e V) is higher than the energies of physical adsorption (these around 0.40 e V-0.50 e V) and close to the energy of cesium condensation.
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Kalered, Emil. "Quantum chemical studies of the chloride-based CVD process for Silicon Carbide." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-85548.
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In this report the interaction between SiH2 molecules and a SiC-4H (0001) surface and SiCl2 molecules and a SiC-4H (0001) surface is investigated. This is done using a cluster model to represent the surface. First the clusters are investigated by calculating some properties to compare with experimental data to motivate the use of the cluster model. The band gap calculated by extrapolation for an infinitely large cluster is 3.75 eV which is fairly close to the experimental value of 3.2 eV. Adsorption studies are performed and the main conclusion is that the SiH2 molecule adsorbs more strongly on the surface then the SiCl2 molecule, adsorption energies are calculated to approximately 200 kJ mol-1 and 100 kJ mol-1 respectively. At the end a few migration studies are performed with the conclusion that SiCl2 more easily can diffuse on the surface compared to the SiH2 molecule. The respective activation energies for migration on the surface are 4 kJ mol-1 for SiCl2 and 87 kJ mol-1 for SiH2.
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Luberti, Mauro. "Design of a H2 pressure swing adsorption process at an advanced IGCC plant for cogenerating hydrogen and power with CO2 capture." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/19577.
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Strong dependency on fossil fuels and the associated price and supply chain risk increase the need for more efficient utilisation of existing non-renewable energy sources. Carbon capture and hydrogen purification technologies are expected to play a key role in the future low-carbonised energy matrix. Integrated Gasification Combined Cycles (IGCCs) are one of the emerging clean coal technologies which pave the way for producing power from coal with a higher net power efficiency than conventional PC-fired boiler power plants. It is also advantageous that in an IGCC power plant a carbon capture unit can be applied to a stream having a very high CO2 partial pressure ahead of gas combustion that would not be available in case of a PC-fired boiler power plant, leading to less energy penalty involved in carbon capture. At the same time, the production of ultrapure hydrogen is both a sought target and an appropriate environmental solution because it is commonly utilised as feedstock in refineries’ hydrotreaters and hydrocrackers as well as energy carrier in fuel cells. A high purity of hydrogen has been commercially produced out of raw synthesis gas using a Hydrogen Pressure Swing Adsorption (H2 PSA) process. In this thesis, it was aimed to design and optimise a bespoke H2 PSA system tailored for a decarbonised syngas feed originating from a carbon capture unit. Therefore, a novel H2 PSA has been studied that is applied to an advanced IGCC plant for cogenerating power and ultrapure hydrogen (99.99+ mol%) with pre-combustion CO2 capture. In designing the H2 PSA, it is essential to increase the recovery of ultrapure hydrogen product to its maximum since the power consumption for compressing the H2 PSA tail gas up to the gas turbine operating pressure should be minimised to save the total auxiliary power consumption. Hydrogen recovery was raised by increasing the complexity of the PSA step configuration that allows a PSA cycle to have a lower feed flow to one column being used for adsorption and more pressure equalisation steps. An in-depth economic analysis was carried out and discussed in detail. The industrial advanced IGCC performances have also been improved by process integration between the H2 PSA unit and other units in the plant.
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Cabrera-Codony, Alba. "Siloxane removal in the energy recovery of biogas: sequential adsorption/oxidation processes." Doctoral thesis, Universitat de Girona, 2016. http://hdl.handle.net/10803/399731.
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The thesis deals with removal of organosilicon compounds in the energy recovery of biogas. Alternative adsorbents for the siloxane removal were studied, and the physical and chemical mechanisms involved in the siloxane adsorption were discovered, which improved the yield of the adsorption and regeneration technologies using both activated carbons and zeolites. Moreover, several technologies based on advanced oxidation processes have been applied in order to regenerate and reuse the exhausted adsorbents.
The thesis studies the siloxane removal at lab-scale close to real scenario conditions, including the competitive adsorption with compounds usually found in biogas, in the presence of humidity and with the same gas matrix, which allowed to select the most efficient materials for this purpose. Therefore, the knowledge reported in the thesis dissertation is directly transferable to field application to upgrade the siloxane removal systemAquesta tesi estudia l'eliminació de compostos volàtis de silici (siloxans) per la recuperació energètica del biogàs. Es van estudiar diferents adsorbents per l'adsorció de siloxans, determinants les propietats físico-químiques superficials que en condicionen l'eficiència, permetent millorar el rendiment de l'adsorció i permetent la regeneració en carbons actius i zeolites esgotats. La tesi estudia l'eliminació de siloxans a escala de laboratori en condicions properes a les reals del biogàs, incloent l'adosrció competitiva amb altres compostos orgànics volàtics, en presència d'humitat i amb diferents matrius gasoses, la qual cosa va permetre seleccionar els materials òptims per aquest propòsit.Per tant el coneixement derivat d'aquesta tesi és directament transferible per tal de millorar els sistemes d'eliminació siloxanes
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Ayissi, Serge Olivier. "Simulation of chiral ordering process in the adsorption of chiral organic molecules on metal surfaces by Monte Carlo methods." Thesis, University of Liverpool, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490608.
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Experimental observations have shown that haloalkane molecules, e.g. l-cWorododecane, physisorbed on Si(111)-(7 x 7) self-assemble to form dimers stable to 100° C which corral silicon adatoms. The corral size is governed by the haloalkane chain-length. Spectroscopic and theoretical evidence shows that the haloalkane dimer induces electron transfer to the corralled adatom. The enclosed silicon adatom, within a bistable dimeric corral of self-assembled chlorododecane molecules, switches its energy levels permanently (Type-II corrals) or discontinuously (Type-I corrals). Both types of corral, switching and stable, can be seen to alter the local surface charge distribution. Density Functional Theory and electron transport (STM) simulations of the switch and the stable molecular configurations can help the theoretical understanding of both phenomena in order to characterized the exact molecular conformations that produce field effects to the corralled silicon adatom and local surface charge distribution. Chiral heterogeneous catalysts are mostly fabricated from chiral molecules on a metal support. They playa crucial role in intermediate reactions in the fabrication of pharmacies, itself and important part of today's health econolPY. However, the key parameters in the fabrication of these catalysts, a requirements for their rational design, are still poorly understood despite years of experimental research. In essence, such an understanding can only come from high-level simulations. Here, we present the first predictions about the structure of such a catalyst, tartaric acid on a copper support, over the whole phase space of temperature and coverage. Interestingly, we find that molecular vibrations playa key role in the ensuing ordered structures, and that tuning the fabrication temperature should allow for a wide range of molecular separations, which can be targeted at specific molecules and reactions in chiral heterogeneous catalysis.
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Duarte, Mendes Catita Leonor. "Contribution of NMR and Raman imaging for modeling and rationalization of the impregnation process of metallic precursors in porous media." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1262/document.
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Cette thèse s’inscrit dans le domaine de la catalyse hétérogène pour des applications en raffinage et en pétrochimie. Plus particulièrement, nous avons choisi d’étudier le cas des catalyseurs d’hydrotraitement largement utilisés dans les procédés de conversion du pétrole en carburant. Ces catalyseurs sont constitués d’une phase métallique sulfurée supporté sur un support poreux inorganique.Dans ce travail, nous nous sommes particulièrement intéressés à la compréhension et la modélisation de la première étape de préparation d’un catalyseur d’hydrotraitement : l’étape d’imprégnation. Une méthodologie innovante basée sur la technique d’imagerie RMN qui permet d’observer operando le transport des précurseurs métalliques dans le support et sur la technique d’Imagerie Raman a été développée. Les résolutions spatiales et temporelles obtenues ont permis de valider cette méthodologie pour caractériser l’étape d’imprégnation en termes de phénomènes physiques (capillarité et diffusion) et chimiques (interaction de surface) et pour identifier les descripteurs clés de cette étape.En conclusion, ces travaux permettront un meilleur contrôle de l'étape d'imprégnation et donc du profil de distribution de la phase active, ce qui aura une forte répercussion sur la performance catalytiqueThe objective of this work is to characterize the impregnation step in terms of physical phenomena (capillarity and diffusion) and chemical phenomena (surface interaction) in order to identify the key descriptors of this step in order to improve the preparation hydrotreating catalysts. This involves monitor spatial and temporally the transport of the species in the impregnation solution within the porosity, more particularly in the case of Ni(Co)MoP/?-Al2O3 catalysts preparation.An original MRI approach has been developed to follow in-situ the impregnation step from a solution of mixed nature with more than one metal precursor in the presence of an additive. MRI provides access to the spatial distribution of all species within the catalyst with a spatial resolution of 39 × 39 µm. Raman imaging allows an identification of the chemical nature of the species in solution with a spatial resolution of 16.2 × 16.2 µm.First, the phenomena involved in the impregnation of model solutions composed of Ni (or Co), were studied by modifying the parameters of the solution. These experiments were then used as the basis for the development of a mathematical model to rationalize the impregnation step. In a second part, this study was extended to the preparation of hydrotreatment catalysts. Several phenomena have been evaluated here, notably the impact of the presence of phosphorus on the transport of Mo species, possible competition of adsorption between P, Co and Mo and the effect of the presence of citric acid.This study allows a better control of the impregnation step and thus of the distribution profile of the active phase, which has an impact on the catalytic performance
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Lesage, Geoffroy. "Etude de l'élimination de substances aromatiques dangereuses dans un procédé couplant adsorption et biodégradation." Phd thesis, INSA de Toulouse, 2009. http://tel.archives-ouvertes.fr/tel-00474706.
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La présence de micropolluants à l'entrée des opérations d'épuration d'effluents industriels induit des problèmes au cours du traitement par des procédés biologiques, certaines molécules n'étant pas nécessairement disponibles à la biodégradation. Parmi les molécules présentes dans les rejets d'origine pétrochimique ou chimique, les substances prioritaires les moins volatiles sont aussi les plus hydrophobes (ex : Hydrocarbures Aromatiques Polycycliques) et ont tendance à s'adsorber majoritairement sur les matières organiques et les boues. A l'inverse, les molécules moins hydrophobes mais très volatiles comme les Benzène, Toluène, Ethylbenzène et p-Xylène ont une forte propension à être transférées dans l'atmosphère lors des phases d'aération. Le bioréacteur hybride étudié ici, reposant sur l'addition de supports adsorbants dans des procédés à boues activées, présente de nombreux avantages. D'une part l'addition de charbon actif en grain dans des procédés à boues activées permet de fixer les polluants ciblés, minimiser leur volatilisation et augmenter leur temps de séjour dans le procédé D'autre part, la réduction de leur concentration à un niveau non inhibiteur permet l'absorption des variations de charges qui sont fréquentes dans les effluents industriels. Enfin les supports ajoutés, sur lesquels se développent des biofilms, constituent des niches écologiques nouvelles pour les micro-organismes les plus lents à se développer. Ces derniers peuvent dégrader les molécules adsorbées dans les zones biorégénérables du charbon actif. Afin de caractériser les mécanismes physicochimiques et biologiques, des expériences en batch des phénomènes découplés et couplés ont été réalisées : cinétiques et isothermes d'adsorption et de biosorption, cinétiques de volatilisation et respirométrie. Egalement, deux pilotes à l'échelle laboratoire ont permis de suivre les performances épuratoires d'un bioréacteur séquencé conventionnel et d'un bioréacteur hybride à support adsorbant. Un modèle d'adsorption sur support hétérogène, développé sous Matlab® et un modèle intégrant le couplage des phénomènes en dynamique, développé sous Aquasim® ont été combinés. Le modèle global développé permet de simuler de façon dynamique le devenir des micropolluants (les outils précédents ne fonctionnant qu'en régime permanent). Les simulations réalisées concordent avec les résultats expérimentaux et permettent de conclure que les mécanismes d'élimination abiotiques jouent un rôle très important dans les « performances épuratoires » du procédé de traitement biologique aérobie conventionnel. Les transferts de BTEX de la phase liquide vers le compartiment gazeux sont significatifs (>99% en 2 heures) et les quantités d'HAPs détectées dans la fraction solide sont importantes (élimination moyenne >65% lors de la décantation primaire). Pour les Composés Organiques Volatiles (ex : BTEX), l'ajout de particules adsorbantes et l'analyse des modes opérationnels minimisant le transfert dans la phase gaz sont les points prépondérants. Des simulations prospectives mettant en jeu les phénomènes conjoints de biodégradation et d'adsorption du toluène et du naphthalène ont permis de montrer que le réseau méso-macroporeux est régénérable, que l'adsorption a lieu majoritairement dans ce compartiment et que le taux de biorégénération dépend de la quantité de biomasse maintenue. L'efficacité des bioréacteurs à supports adsorbants (Charbon Actif en Grain) a été démontré pour ces molécules, à conditions de gérer une période de biorégénération qui devra être optimisée à partir du modèle développé.
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Kangas, J. (Jani). "Separation process modelling:highlighting the predictive capabilities of the models and the robustness of the solving strategies." Doctoral thesis, Oulun yliopisto, 2014. http://urn.fi/urn:isbn:9789526203768.
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Abstract The aim of this work was to formulate separation process models with both predictive capabilities and robust solution strategies. Although all separation process models should have predictive capabilities, the current literature still has multiple applications in which predictive models having the combination of a clear phenomenon base and robust solving strategy are not available. The separation process models investigated in this work were liquid-liquid phase separation and membrane separation models. The robust solving of a liquid-liquid phase separation model typically demands the solution of a phase stability analysis problem. In addition, predicting the liquid-liquid phase compositions reliably depends on robust phase stability analysis. A phase stability analysis problem has multiple feasible solutions, all of which have to be sought to ensure both the robust solving of the model and predictive process model. Finding all the solutions with a local solving method is difficult and generally inexact. Therefore, the modified bounded homotopy methods, a global solving method, were further developed to solve the problem robustly. Robust solving demanded the application of both variables and homotopy parameter bounding features and the usage of the trivial solution in the solving strategy. This was shown in multiple liquid-liquid equilibrium cases. In the context of membrane separation models, predictive capabilities are achieved with the application of a Maxwell-Stefan based model. With the Maxwell-Stefan approach, multicomponent separation can be predicted based on pure component permeation data alone. On the other hand, the solving of the model demands a robust solving strategy with application-dependent knowledge. These issues were illustrated in the separation of a H2/CO2 mixture with a high-silica MFI zeolite membrane at high pressure and low temperature. Similarly, the prediction of mixture adsorption based on pure component adsorption data alone was successfully demonstrated. In the context of membrane separation models, predictive capabilities are achieved with the application of a Maxwell-Stefan based model. With the Maxwell-Stefan approach, multicomponent separation can be predicted based on pure component permeation data alone. On the other hand, the solving of the model demands a robust solving strategy with application-dependent knowledge. These issues were illustrated in the separation of a H2/CO2 mixture with a high-silica MFI zeolite membrane at high pressure and low temperature. Similarly, the prediction of mixture adsorption based on pure component adsorption data alone was successfully demonstratedTiivistelmä Työn tavoitteena oli muotoilla prosessin käyttäytymisen ennustamiseen kykeneviä erotusprosessimalleja ja niiden ratkaisuun käytettäviä luotettavia strategioita. Vaikka kaikkien erotusprosessimallien tulisi olla ennustavia, on tällä hetkellä useita kohteita, joissa prosessin käyttäytymistä ei voida ennustaa siten, että käytettävissä olisi sekä ilmiöpohjainen malli että ratkaisuun soveltuva luotettava strategia. Tässä työssä erotusprosessimalleista kohteina tarkasteltiin neste-neste-erotuksen ja membraanierotuksen kuvaukseen käytettäviä malleja. Neste-neste-erotusmallien luotettava ratkaisu vaatii yleensä faasistabiilisuusongelman ratkaisua. Lisäksi faasien koostumusten luotettava ennustaminen pohjautuu faasistabiilisuusanalyysiin. Faasistabiilisuusongelmalla on useita mahdollisia ratkaisuja, jotka kaikki tulee löytää, jotta voitaisiin varmistaa luotettava mallin ratkaisu sekä prosessimallin ennustuskyvyn säilyminen. Kaikkien ratkaisujen löytäminen on sekä vaikeaa että epätarkkaa paikallisesti konvergoituvilla ratkaisumenetelmillä. Tämän vuoksi globaaleihin ratkaisumenetelmiin kuuluvia modifioituja rajoitettuja homotopiamenetelmiä kehitettiin edelleen, jotta faasistabiilisuusongelma saataisiin ratkaistua luotettavasti. Ratkaisun luotettavuus vaati sekä muuttujien että homotopiaparametrin rajoittamista ja ongelman triviaalin ratkaisun käyttöä ratkaisustrategiassa. Tämä käyttäytyminen todennettiin useissa neste-nestetasa-painoa kuvaavissa esimerkeissä. Membraanierotusta tarkasteltaessa ennustava malli voidaan muotoilla käyttämällä Maxwell-Stefan pohjaista mallia. Maxwell-Stefan lähestymistavalla voidaan ennustaa monikomponenttiseosten erotusta perustuen puhtaiden komponenttien membraanin läpäisystä saatuun mittausaineistoon. Toisaalta mallin ratkaisu vaatii luotettavan ratkaisustrategian, jossa hyötykäytetään kohteesta riippuvaa tietoa. Näitä kysymyksiä havainnollistettiin H2/CO2 seoksen erotuksessa MFI-zeoliitti-membraanilla korkeassa paineessa. Samoin seosten adsorboitumiskäyttäytymistä ennustettiin onnistuneesti pelkästään puhtaiden komponenttien adsorptiodatan pohjalta. Kokonaisuutena voidaan todeta, että tarkasteltujen erotusprosessimallien ennustavuutta voidaan parantaa yhdistämällä malli, jolla on selkeä ilmiöpohja ja luotettava ratkaisustrategia. Lisäksi mallien käytettävyys erotusprosessien suunnittelussa on parantunut työn tulosten pohjalta
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Luo, Lieh-Chyr, and 羅烈池. "Study of Dynamical Behaviors of Adsorption Process." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/48089536143577501000.
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Hsu, Chia-Hsin, and 徐嘉欣. "Removal of antimony from water by adsorption process." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/48373218389574466705.
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碩士淡江大學
水資源及環境工程學系碩士班
100
This research evaluated the capability of adsorbed Sb(III) and Sb(V) by three various adsorbents. The effects to the adsorption of Sb(III) and Sb(V) resulting from the type and dosage of adsorbents, reaction time, pH, initial Sb concentration, and competitive anions were investigated. Kinetic studies suggested that the adsorption equilibriums for both Sb(III) and Sb(V) were reached within 24 h. The results show that the order of adsorption efficiency by different adsorbent is GFH>Mnz>PAC and the efficiency of GFH is 23 times better than PAC. The amount of Sb(III) been adsorbed by GFH is 2.9 times larger than Sb(V) due to the chemical formation of Sb(OH)3 and Sb(OH)6- respectively. The optimum pH for adsorption of Sb ranged from 3 to 8 and can reach more than 85% removal efficiency. In the pH range from 8 to 10, the adsorption of Sb by GFH decreased with increasing pH. PAC is not suitable as an adsorbent for adsorption of Sb while GFH is accessible. When the dosage of GFH is fixed, the adsorption efficiency of Sb increased with increasing of initial concentration of Sb. The Freundlich isotherm model could better describe the phenomena of Sb adsorption by GFH than Langmuir model. The n value in Freundlich model increased with increasing initial concentration of Sb and n value of Sb(III) is larger than Sb(V)’s. The best fit kinetic models of modeling adsorption of Sb by GFH are pseudo-second-order model and intraparticle diffusion model. Keywords: antimony, granular ferric hydroxide, adsorption, competitive anions, Freundlich isotherm
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Freitas, Francisco Avelino da Silva. "Cyclic adsorption process : Application to propane/propylene separation." Tese, 1999. http://hdl.handle.net/10216/12366.
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Freitas, Francisco Avelino da Silva. "Cyclic adsorption process : Application to propane/propylene separation." Doctoral thesis, 1999. http://hdl.handle.net/10216/12366.
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Ju, Dou-Ming, and 朱德銘. "Simulation of a Fractionated Vacuum Swing Adsorption Process for." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/68419417648072619934.
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碩士國立中央大學
化學工程研究所
83
Pressure swing adsorption (PSA) is a process essentially consisting of cyclic steps, which are widely used for separation of gas mixtures through the utilization of adsorbents that have favorable selectivity for components of the gas mixtures. Vacuum swing adsorption (VSA) is a kind of PSA which operates below atmosphere pressure by using vacuum pump during the desorption step. A fractionated vacuum swing adsorption (FVSA) process that simultaneously produce a 98+% nitrogen enriched gas and a 80-90% oxygen enriched gas from ambient air is studied by simulation. This process uses CaX zeolite as the major adsorbent and alumina as a desiccant packed at the feed air end. Because the pore size of CaX zeolite is large, the mass transfer resistance between the gas and adsorbed phase can be neglected. For this reason, we use the local equilibrium model by assuming instantaneous concentration equilibrium between the gas and solid phases at all points in the bed. To develop the simulation program for the FVSA process with multicomponent feed gas and multiple adsorbents sectionally packed in the same bed, we apply the method of lines with adaptive grid points combined with the estimation of the spatial derivatives by cubic spline/finite difference to discretize the PDEs into a set of ODEs, then the set of ODEs is integrated with respect to time by using subroutine LSODE of ODEPACK to obtain the dynamic solution of this system. In the isothermal simulation, the feed air is considered as a ternary mixture including nitrogen, oxygen and water vapor, and the dynamic behavior of the adsorption bed and the effects of humidity are studied. The simulation results agree reasonably with the experimental data obtained elsewhere, and show the reliability of this FVSA simulation program. The optimal operation conditions of the FVSA process are to be studied by using the accuracy-validated simulation program.
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Afewu, Kodjo Isaac. "Scale-up in carbon-in-pulp adsorption process systems." Thesis, 2016. http://hdl.handle.net/10539/21568.
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A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements of the degree of Master of Science in Engineering.
Johannesburg, 1992An investigation was undertaken into the influence of agitation intensity on the adsorption of aurocyanide from slurries onto activated carbon. [ Abbreviation abstract. Open document to view full version]
GR2016