Acidentes ambientais vêm ocorrendo ao longo de décadas, assim, além de atitudes para evitar esses danos, são necessárias ações para remediação. Materiais tecnológicos e de baixo custo em impacto ambiental podem ser uma alternativa para o tratamento de corpos hídricos degradados, além de um caminho ambientalmente sustentável para remediação de córregos e rios urbanos. Neste contexto, buscou-se avaliar na pesquisa, materiais biossorventes para serem utilizados em acidentes de derramamento de derivados do petróleo em meio aquático. Como matéria-prima, utilizaram-se as fibras das cascas de banana, coco e laranja. Como contaminantes foram utilizados a gasolina e o óleo diesel. Os biossorventes foram produzidos por processos de secagem, ativação química, moagem, classificação granulométrica, caracterização e ensaios de sorção. Para a caracterização foram empregadas as técnicas: picnometria, termogravimetria, análise elementar, microscopia eletrônica de varredura, teor de umidade, retenção de água pela biomassa seca, hidrofobicidade, flutuabilidade, teor de cinzas, fluorescência de raios X e classificação granulométrica. Para o tratamento dos dados, desenvolveu-se um planejamento estatístico de identificação das variáveis significativas no processo de sorção, construíram-se curvas de equilíbrio e de cinética de sorção e que foram modeladas por meio das isotermas de Freundlich e Langmuir. Para estudo da influência da granulometria na sorção, os ensaios foram realizados com os grãos primeiramente de maneira generalizada e posteriormente separados por granulometrias distintas. Os resultados se mostraram promissores, sendo o coco o biossorvente mais eficiente, ele sorveu uma média de 3,94 g/g de óleo diesel e 2,80 g/g de gasolina. / Environmental accidents have been occurring for decades, then, in addition to attitudes to avoid such damages, remediation actions are required. Technological materials of low cost and environmental impact may be an alternative for the treatment of degraded water bodies, besides an environmentally sustainable way for remediation of streams and urban rivers. In this context, it was sought to evaluate, in the research, biosorbent materials to be used in accidents of spill of oil derivatives in aquatic environment. The fibers of the banana, coconut and orange crusts were used as raw material. Petrol and diesel were used as contaminants. The biosorbents were produced by processes such as, drying, chemical activation, milling, sorting, characterization and sorption tests. For the characterization, the techniques used were: picnometry, thermogravimetry, elemental analysis, electron microscopy, moisture content, water retention by dry biomass, hydrophobicity, buoyancy, ash content, X - ray fluorescence and granulometric classification. For the treatment of the data, a statistical design was developed to identify the significant variables in the sorption process, equilibrium and sorption kinetics curves were constructed and modeled, using the Freundlich and Langmuir isotherms. To study the influence of granulometry on sorption, the tests were performed with the grains first generalized and later separated by different granulometries. The results were promising, with coconut being the most efficient biosorbent, it had an average of 3,94 g/g of diesel oil and 2,80 g/g of gasoline.

Acidentes ambientais vêm ocorrendo ao longo de décadas, assim, além de atitudes para evitar esses danos, são necessárias ações para remediação. Materiais tecnológicos e de baixo custo em impacto ambiental podem ser uma alternativa para o tratamento de corpos hídricos degradados, além de um caminho ambientalmente sustentável para remediação de córregos e rios urbanos. Neste contexto, buscou-se avaliar na pesquisa, materiais biossorventes para serem utilizados em acidentes de derramamento de derivados do petróleo em meio aquático. Como matéria-prima, utilizaram-se as fibras das cascas de banana, coco e laranja. Como contaminantes foram utilizados a gasolina e o óleo diesel. Os biossorventes foram produzidos por processos de secagem, ativação química, moagem, classificação granulométrica, caracterização e ensaios de sorção. Para a caracterização foram empregadas as técnicas: picnometria, termogravimetria, análise elementar, microscopia eletrônica de varredura, teor de umidade, retenção de água pela biomassa seca, hidrofobicidade, flutuabilidade, teor de cinzas, fluorescência de raios X e classificação granulométrica. Para o tratamento dos dados, desenvolveu-se um planejamento estatístico de identificação das variáveis significativas no processo de sorção, construíram-se curvas de equilíbrio e de cinética de sorção e que foram modeladas por meio das isotermas de Freundlich e Langmuir. Para estudo da influência da granulometria na sorção, os ensaios foram realizados com os grãos primeiramente de maneira generalizada e posteriormente separados por granulometrias distintas. Os resultados se mostraram promissores, sendo o coco o biossorvente mais eficiente, ele sorveu uma média de 3,94 g/g de óleo diesel e 2,80 g/g de gasolina. / Environmental accidents have been occurring for decades, then, in addition to attitudes to avoid such damages, remediation actions are required. Technological materials of low cost and environmental impact may be an alternative for the treatment of degraded water bodies, besides an environmentally sustainable way for remediation of streams and urban rivers. In this context, it was sought to evaluate, in the research, biosorbent materials to be used in accidents of spill of oil derivatives in aquatic environment. The fibers of the banana, coconut and orange crusts were used as raw material. Petrol and diesel were used as contaminants. The biosorbents were produced by processes such as, drying, chemical activation, milling, sorting, characterization and sorption tests. For the characterization, the techniques used were: picnometry, thermogravimetry, elemental analysis, electron microscopy, moisture content, water retention by dry biomass, hydrophobicity, buoyancy, ash content, X - ray fluorescence and granulometric classification. For the treatment of the data, a statistical design was developed to identify the significant variables in the sorption process, equilibrium and sorption kinetics curves were constructed and modeled, using the Freundlich and Langmuir isotherms. To study the influence of granulometry on sorption, the tests were performed with the grains first generalized and later separated by different granulometries. The results were promising, with coconut being the most efficient biosorbent, it had an average of 3,94 g/g of diesel oil and 2,80 g/g of gasoline.

Forward Osmosis (FO) is an emerging technology which has potential to operate with minimum energy input. High performance of FO systems depend on the availability of a suitable Draw Solution. Different types of Draw Solutions have been proposed, however; choosing a suitable one is still a developing area within the FO field. There is an urgent need to explore new materials in order to develop an efficient FO system. The current study aims at investigating the performance of three Draw Solutions namely, L-Alanine, DADMAC and PolyDADMAC as osmotic agents for FO. These organic cationic solutions can be used as extraction agents of water from poorer quality organic solutes such as fumaric acid solution produced in a continuous flow microbial fermentation process. The performance of the three Draw Solutions was evaluated by measuring the water flux and reverse solute diffusion at different concentrations. The viability of reconcentration of the diluted Draw Solutions was also investigated using Nanofiltration system. The performance and the efficiency of the Draw Solutions were studied via two separated bench scale systems of FO and Nanofiltration. Both Cellulose Triacetate (CTA) and Thin Film Composite (TFC) aquaporin protein FO membranes were employed under different orientations in FO set up operated for 24 hours or longer. In this study, NF90 membrane was used for reconcentration the Draw Solutions. A series of experiments were conducted to obtain the best water flux and reverse solute diffusion under various influencing operating conditions. The experiments were designed to achieve three objectives, i.e. (i) optimum operating conditions for FO system, (ii) optimum operating conditions for the reconcentration system, and (iii) implementation of the optimum operating conditions of the FO system for water recovery from a fumaric acid solution produced by a simulated industrial fermentation process. In the initial stage, L-Alanine Draw Solution demonstrated that it was the most viable agent for FO. It was established that L-Alanine Solution at 0.085 g/mL concentration achieved the highest initial water flux and the lowest reverse solute diffusion through both CTA and TFC aquaporin protein FO membranes. In the second stage, a Nanofiltration system was proven to be effective in the reconcentration of the diluted L-Alanine Draw Solution. The average rejection of L-Alanine ions achieved by NF90 membrane was 96.00%. Drawing on the previous results, the third stage was used to investigate the viability of the FO system in water recovery from fumaric acid solution produced by continuous microbial fermentation process using L-Alanine as a Draw Solution. The reduction of water content of the fumaric acid solution made it to concentrate by 26.00% and 19.80% in 32_ and 17_, respectively. Consequently, FO technology is an effective way to concentrate a fumaric acid solution produced by continuous microbial fermentation process. Based on the results, it is recommended that LAlanine should be proposed in the FO process according to its reliability and effectiveness as a viable draw agent. TFC aquaporin protein membrane is also recommended to be used in recover the water from fumaric acid solution produced by fermentation processes. Further studies should be done to investigate the viability of FO in water recovery from advanced application such as downstream bioprocessing. / Dissertation (MEng)--University of Pretoria, 2017. / Chemical Engineering / MEng / Unrestricted

Livestock wastewater contains a large amount of nutrients that are available for recovery. In this study, a proof of concept process based on forward osmosis (FO) was proposed and investigated for in-situ formation of struvite from digested swine wastewater. This FO system took advantage of a drawback reverse solute flux (RSF) and used the reversed-fluxed Mg^{2+} for struvite precipitation, thereby accomplishing recovery of both water and nutrient. With 0.5 M MgCl2 as a draw solution, high purity struvite formed spontaneously in the feed solution and the water flux through the FO membrane reached 3.12 LMH. The precipitated struvite was characterized and exhibited a similar composition to that of commercial struvite. The FO system achieve >50% water recovery, >99% phosphate recovery (given sufficient magnesium supply), and >93% ammonium nitrogen removal from the digested swine wastewater. The recovered products (both struvite and water) could potentially generate a value of 1.35 $ m^{-3}. The results of this study have demonstrated the feasibility of nutrient recovery from livestock wastewater facilitated by FO treatment. / Master of Science

The Water Recovery System (WRS) is one of the necessary subsystems in an Advanced Life Support program. It regenerates potable water by processing wastewater generated on a space shuttle or on a space station. The Biological Water Processor (BWP) is one of the complex subsections of WRS that involves processes described by continuous time as well as discrete event dynamics. Such systems can be modeled as hybrid dynamical systems in MATLAB/Stateflow. The following state variables of the BWP have been simulated in MATLAB: Pressure drop across Organic Carbon Oxidation Reactor (OCOR), Pressure drop across nitrification reactor, nitrifier flow rate, total flow to OCOR, Gas-liquid separator level, feed pump modes. The developed model of the BWP can be used for the simulation of the complete WRS and also for synthesis of a distributed control laws for the BWP subsection.

No description available.

Yes / Brackish water can be considered an important source of fresh water, via desalination, especially for arid districts. Reverse Osmosis (RO) process has been successfully used to produce fresh water from brackish water sources. However, there is still the challenge of improving the performance of multistage RO desalination plants. From the selection of the RO configurations to the selection of the appropriate type of membranes and the operating conditions at the end determines the performance of RO process in terms of recovery, salt rejection, energy consumptions and ultimately the cost of production of freshwater. Using model-based simulation, this work attempts to investigate the most suitable types of membranes for an industrial scale RO plant from a set of different membrane brands that would attain the highest-performance at lowest specific energy consumption (SEC). As a case study, we considered a multistage multi-pass medium-scale RO plant (1200 m3/day) of Arab Potash Company (APC, Jordan) which produces high quality water for the boilers after pre-treatment stage. The simulation results confirmed that employment of the Filmtec BW30LE-440 would increase water recovery by about 22% besides reducing the product salinity and SEC by about 15% and 10%, respectively compared to the existing membrane.

Usinas Termelétricas (UTEs), compostas por ciclo simples a vapor e ciclo combinado, são instalações industriais que consomem elevadas quantidades de água, sobretudo por conta de suas operações de resfriamento e de geração de vapor. Paralelamente, tem-se observado a redução de oferta deste recurso em muitas regiões onde se encontram instaladas unidades termelétricas, fato que suscita a preocupação, o debate e a pesquisa acerca do desenvolvimento de tecnologias e estratégias direcionadas à mitigação do consumo e reaproveitamento de água em UTEs. Em contrapartida, do mesmo modo que UTEs são intensivas no consumo de água, esta é também produzida na forma de vapor em escalas significativas como resultado do processo de combustão. Contudo, a parcela de água produzida é lançada para a atmosfera juntamente com os demais gases produzidos (CO2, N2, O2, SO2). Frente a esse contexto, este trabalho se divide em duas etapas distintas. A primeira voltada à estimativa da quantidade de água e demais componentes presentes nos gases de combustão de trinta e seis UTEs brasileiras, dentre as quais vinte e duas são movidas a gás natural (ciclos simples e combinados) e quatorze a carvão mineral (ciclos simples). Tais estimativas levam em conta as condições ambientais do local de operação, a eficiência típica do ciclo e a composição do combustível empregado. A segunda etapa trata da modelagem e da simulação, sob diferentes condições operacionais (pressão, temperatura de resfriamento e porcentagem de vapor de água nos gases), de um condensador duplo tubo vertical operando sob regime de convecção natural no lado do resfriamento, a partir do qual se estuda o processo de condensação do vapor de água na presença dos demais gases produzidos, estes conhecidos como gases não condensáveis (GNC). Tais simulações tem o propósito de avaliar as taxas de recuperação de água capazes de serem obtidas por meio do condensador/processo idealizado. / Single and combined steam cycle thermoelectric plants are power plants that consume high amounts of water, mainly from the cooling and steam generation operations. At the same time, there have been a reduction in the supply of this resource in many regions where thermoelectric units are installed. This fact increases the concern, discussion, and research on the development of technologies and new strategies directed to the mitigation of the consumption and reutilization of water. On the other hand, likewise UTEs are intensive in water consumption, they also produce it at significant amounts of steam from the combustion process, and that amount of water produced is released to the atmosphere together with gases produced (CO2, N2, O2, SO2). In this sense, this work is divided into two distinct parts. The first one is aimed at estimating the amount of water and other components present in the flue gases of thirty Brazilian thermal power plants, of which twenty-two are powered by natural gas (single and combined cycles) and eight moved by coal (single cycles). Such estimates consider environmental conditions of the operation site, typical cycle efficiency, and fuel composition employed. The second part deals with a numerical modeling and simulation, at different operating conditions (pressure, cooling temperature, and water vapor content in the gases), of a double vertical tube condenser operating by natural convection on the cooling side, from which the condensation process of the water vapor is studied in the presence of the other gases produced (known as non-condensable gases, NCG). These simulations have the fundamental purpose of evaluating the rates of condensate that can be recovered by means of the condenser/idealized process.

Usinas Termelétricas (UTEs), compostas por ciclo simples a vapor e ciclo combinado, são instalações industriais que consomem elevadas quantidades de água, sobretudo por conta de suas operações de resfriamento e de geração de vapor. Paralelamente, tem-se observado a redução de oferta deste recurso em muitas regiões onde se encontram instaladas unidades termelétricas, fato que suscita a preocupação, o debate e a pesquisa acerca do desenvolvimento de tecnologias e estratégias direcionadas à mitigação do consumo e reaproveitamento de água em UTEs. Em contrapartida, do mesmo modo que UTEs são intensivas no consumo de água, esta é também produzida na forma de vapor em escalas significativas como resultado do processo de combustão. Contudo, a parcela de água produzida é lançada para a atmosfera juntamente com os demais gases produzidos (CO2, N2, O2, SO2). Frente a esse contexto, este trabalho se divide em duas etapas distintas. A primeira voltada à estimativa da quantidade de água e demais componentes presentes nos gases de combustão de trinta e seis UTEs brasileiras, dentre as quais vinte e duas são movidas a gás natural (ciclos simples e combinados) e quatorze a carvão mineral (ciclos simples). Tais estimativas levam em conta as condições ambientais do local de operação, a eficiência típica do ciclo e a composição do combustível empregado. A segunda etapa trata da modelagem e da simulação, sob diferentes condições operacionais (pressão, temperatura de resfriamento e porcentagem de vapor de água nos gases), de um condensador duplo tubo vertical operando sob regime de convecção natural no lado do resfriamento, a partir do qual se estuda o processo de condensação do vapor de água na presença dos demais gases produzidos, estes conhecidos como gases não condensáveis (GNC). Tais simulações tem o propósito de avaliar as taxas de recuperação de água capazes de serem obtidas por meio do condensador/processo idealizado. / Single and combined steam cycle thermoelectric plants are power plants that consume high amounts of water, mainly from the cooling and steam generation operations. At the same time, there have been a reduction in the supply of this resource in many regions where thermoelectric units are installed. This fact increases the concern, discussion, and research on the development of technologies and new strategies directed to the mitigation of the consumption and reutilization of water. On the other hand, likewise UTEs are intensive in water consumption, they also produce it at significant amounts of steam from the combustion process, and that amount of water produced is released to the atmosphere together with gases produced (CO2, N2, O2, SO2). In this sense, this work is divided into two distinct parts. The first one is aimed at estimating the amount of water and other components present in the flue gases of thirty Brazilian thermal power plants, of which twenty-two are powered by natural gas (single and combined cycles) and eight moved by coal (single cycles). Such estimates consider environmental conditions of the operation site, typical cycle efficiency, and fuel composition employed. The second part deals with a numerical modeling and simulation, at different operating conditions (pressure, cooling temperature, and water vapor content in the gases), of a double vertical tube condenser operating by natural convection on the cooling side, from which the condensation process of the water vapor is studied in the presence of the other gases produced (known as non-condensable gases, NCG). These simulations have the fundamental purpose of evaluating the rates of condensate that can be recovered by means of the condenser/idealized process.

Der integrierte Gas-Dampf (GiD-) Prozess mit Wasserrückgewinnung ist ein flexibler Kraft-Wärme-Kopplungsprozess, der die gleichzeitige Bereitstellung von Strom und Wärme teilweise entkoppeln kann. Der effiziente und sparsame Einsatz von fossilen Brennstoffen ist aus ökonomischer wie auch ökologischer Sicht geboten. Die Kraft-Wärme-Kopplung (KWK), die gleichzeitige Erzeugung von Strom und Wärme, ist eine Möglichkeit dafür. Allerdings erfordert die KWK auch eine gleichzeitige Abnahme von Strom und Wärme beziehungsweise deren Speicherung. Sowohl Strom als auch Prozessdampf lassen sich nur aufwendig und damit relativ teuer speichern, weshalb Alternativen gefragt sind. Der GiD-Prozess besteht aus einer Gasturbine mit nachgeschaltetem Abhitzedampfkessel. Die Gasturbine verfügt als Besonderheit über eine Dampfinjektion, die vor, nach oder direkt in die Brennkammer erfolgen kann. Der Abhitzekessel hat zusätzliche Wärmeübertragerflächen um das Abgas bis unter den Taupunkt abzukühlen. Somit kann ein Teil des injizierten Dampfes aus dem Abgas zurückgewonnen und wiederverwendet werden. Der in die Gasturbine injizierte Dampf führt dieser weitere Energie zu. Diese kann entweder zur Leistungssteigerung der Anlage oder zur Reduzierung des fossilen Brennstoffbedarfes genutzt werden. Die erste Option der Leistungssteigerung ist auch als Cheng-Prozess bekannt. Diese Arbeit widmet sich der weniger untersuchten zweiten Möglichkeit der Brennstoffreduzierung. Beim Vergleich des GiD-Prozesses mit verschiedenen anderen Kraftwerks-Prozessen zeigt sich, dass dieser besonders gut für industrielle Anlagen mit Prozessdampfbedarf und einer elektrischen Leistung kleiner 20 MW el geeignet ist. Im Rahmen dieser Arbeit wurde der GiD-Prozess mittels einer Versuchsanlage auf Basis einer Industriegasturbine mit 650 kW el untersucht. Die Arbeit dokumentiert verschiedene Versuchsfahrten und Untersuchungen an dieser Anlage. Die Injektion von Dampf reduziert die Schadstoffemissionen in den zulässigen Bereich und kann sehr flexibel zu einer Steigerung des Anlagenwirkungsgrades von bis zu zwei Prozent führen. Dabei wird der Dampf sehr gleichmäßig in die Versuchsanlage eingebracht, so dass keine signifikanten Änderungen der Abgastemperaturverteilung erkennbar sind. Die Überhitzung des Dampfes kann zu einer weiteren Steigerung des Anlagenwirkungsgrades führen. Die Rückgewinnung des eingebrachten Dampfes ist mit den entsprechenden Wärmeübertragern möglich. Das zurückgewonnene Wasser ist durch die Stickoxide des Abgases verunreinigt und muss entsprechend aufbereitet werden.