• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 16
  • 9
  • 2
  • Tagged with
  • 28
  • 28
  • 15
  • 15
  • 10
  • 8
  • 8
  • 7
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Electrothermic dry distillation of zinc

Goff, Ira Nathan. January 1926 (has links) (PDF)
Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1926. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed September 15, 2009) Includes bibliographical references (p. 60-62).
2

A granular briquet [sic] resistance furnace for the electrothermic dry distillation of zinc ores

Countryman, Milton E. January 1925 (has links) (PDF)
Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1925. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed June 22, 2009) Includes bibliographical references (p. v).
3

Effect of the size of particles of zinc ore and carbon upon the rate of reduction of zinc ore by carbon

Alexander, Keith Oxley. January 1925 (has links) (PDF)
Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1925. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed September 14, 2009) Includes bibliographical references (p. 34).
4

Effect of time and temperature on distillation of zinc-lead-silver complex sulphide concentrates

Wheeler, Ernest Sterling. January 1923 (has links) (PDF)
Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1923. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed June 1, 2010) Includes bibliographical references (p. 55).
5

A granular briquet [sic] resistance furnace for the electrothermic dry distillation of zinc ores

Kahlbaum, William McKinley. January 1925 (has links) (PDF)
Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1925. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed October 9, 2009) Includes bibliographical references.
6

Comparison of Multieffect Distillation and Extractive Distillation Systems for Corn-Based Ethanol Plants

Dion Ngute, Miles Ndika 05 April 2012 (has links)
Recent publications on ethanol production and purification shows optimized energy and water consumptions as low as 22,000 Btu/gal ethanol and 1.54 gal water/gal ethanol respectively using multieffect distillation. Karuppiah, et al use column rating and mathematical optimization methods and shortcut design models to design evaluate and optimize the energy and water consumption. In this work, we compare shortcut design and rigorous simulation models for an ethanol purification distillation system, and we show that distillation systems based on shortcut design underestimate the true energy and water consumption of the distillation system. We then use ASPEN Plus, to design a multieffect distillation system and an extractive distillation system using rigorous simulation and compare the two for energy and water consumptions. We show that the extractive distillation system has lower steam and cooling water consumptions and consequently lower energy and water consumptions than multieffect distillation in corn-to-ethanol production and purification. We also show that the extractive distillation system is cheaper than the multieffect distillation system on a cost per gal ethanol basis. This work gives an energy consumption of 29987 Btu/gal ethanol and water consumptions 2.82 gal/gal ethanol for the multieffect distillation system at a manufacturing cost of $3.03/gal ethanol. For the extractive distillation system, we calculate an energy consumption of 28199 Btu/gal ethanol and a water consumption of 2.79 gal/gal ethanol at a manufacturing cost of $2.88/gal ethanol. / Master of Science
7

Avaliação doefeito do teor de solvente e da integração térmica no controle do processo de obtenção de Etanol Anidro via destilação extrativa. / Evaluation of the effect of the solvent content and the thermal integration in the control of the process of obtaining Ethanol Anhydrous by extractive distillation.

RAMOS, Wagner Brandão. 19 March 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-03-19T17:03:38Z No. of bitstreams: 1 WAGNER BRANDÃO RAMOS - TESE PPGEQ 2016..pdf: 17733872 bytes, checksum: 5e6f59ac00a4f15f43c3f335dc3b2075 (MD5) / Made available in DSpace on 2018-03-19T17:03:39Z (GMT). No. of bitstreams: 1 WAGNER BRANDÃO RAMOS - TESE PPGEQ 2016..pdf: 17733872 bytes, checksum: 5e6f59ac00a4f15f43c3f335dc3b2075 (MD5) Previous issue date: 2016-08-22 / Capes / A destilação extrativa é um método bastante utilizado em indústrias alcooleiras para se obter etanol anidro, cujo processo é composto por duas colunas de destilação, onde a primeira coluna (coluna de destilação extrativa) tem como função desidratar o etanol e a segunda coluna (coluna de recuperação) recuperar o solvente utilizado no processo. Colunas de destilação são responsáveis por um consumo bastante elevado de energia em uma planta e, por isso, diversos métodos de otimização têm sido publicados na literatura, cujos resultados propõem mudanças nas condições operacionais e design do sistema. Além da necessidade de que este sistema opere em condições ótimas, também é necessário se obter um sistema de controle eficiente e que seja capaz de manter o etanol anidro produzido dentro da especificação desejada, mesmo diante distúrbios que ocorrem normalmente neste processo. Sendo assim, o tema deste trabalho surgiu da união destes dois pontos importantes, otimização e controle, no qual o objetivo é estudar o comportamento dinâmico e o controle do processo de destilação extrativa para obtenção de etanol anidro, utilizando etileno glicol como solvente e com integração térmica entre correntes do processo. Sob este escopo, traçou-se objetivos específicos inexistentes na literatura consultada, que são as influências da integração térmica, do teor de solvente e do grau de pureza de etanol anidro que se deseja obter sobre o controle de sistemas de destilação extrativa. Os resultados mostram que o teor de solvente e a presença da integração térmica causam desvios na composição do produto de interesse (etanol anidro), em comparação com o processo sem integração térmica, quando ocorrem distúrbios na alimentação para o mesmo sistema de controle. O grau de pureza de etanol anidro que se deseja obter também causa influência no controle da pureza. De maneira geral, estes efeitos se apresentaram de forma mais acentuada nos casos em que o sistema opera com alto teor de solvente (condição que representa menor consumo energético). Sendo assim, foram propostas modificações no esquema de controle, proporcionando melhores resultados para estes casos. / Extractive distillation is a method widely used in the alcohol industry to obtain anhydrous ethanol, which process consists of two distillation columns where the first column (extractive distillation column) has the function to dehydrate ethanol and the second column (recovery column) recovers the solvent used in the process. Distillation columns are responsible for a very high energy consumption in a plant and thus various methods of optimization, which results suggest changes in operating conditions and system design, have been published in the literature. In addition to the need for this system to operate in optimum conditions, it is also necessary to provide an efficient control system that is able to maintain anhydrous ethanol produced within the desired specification even after the disturbances that normally occur in this process. Thus, the theme of this work arose from the union of these two important points, optimization and control, in which the goal is to study the dynamic behavior and the control of the extractive distillation process for obtaining anhydrous ethanol, using ethylene glycol as a solvent and thermal integration between process streams. Under this scope, specific objectives nonexistent in the literature were drawn, which are the influences of thermal integration, solvent content and the degree of purity of anhydrous ethanol to be obtained on the control of extractive distillation systems. The results show that the solvent content and the presence of thermal integration causes deviations in the product composition of interest (anhydrous ethanol) compared to the process without heat integration, when disturbances occur in the feed for the same control system. The degree of purity of anhydrous ethanol to be obtained also causes influence over controllability. Generally, these effects are exhibited more markedly when the system operates with high solvent content (optimum operating point). So changes were proposed for the control scheme, providing better results for these cases.
8

Reducing the energy demand of bioethanol through salt extractive distillation enabled by electrodialysis

Hussain, Mohammed January 1900 (has links)
Doctor of Philosophy / Department of Chemical Engineering / Peter H. Pfromm / The expanded Renewable Fuel Standard (RFS2), established under the Energy Independence and Security Act (EISA) of 2007, mandates the production of 136.3 GL/year of renewable fuels in the U.S. in 2022: 56.8 GL/year of corn-ethanol, 60.6 GL/year of second generation biofuels such as cellulosic ethanol, and 18.9 GL/year of advanced biofuels such as biomass-based diesel. One of the several challenges when a biochemical conversion technique is used to produce bioethanol from corn and cellulosic feedstock is the high energy demand for recovering and purifying ethanol, which is mainly due to the low concentration of ethanol in the fermentation broth and the challenging water-ethanol vapor liquid equilibrium. Dilute ethanol from the fermentation broth can be separated and concentrated aided by salt extractive distillation to directly produce fuel ethanol leading to significant energy savings. Techniques other than highly energy intensive evaporative salt concentration/crystallization and solids drying for recovering salt, which is used to facilitate distillation, have rarely been considered. In this study, a novel combination of electrodialysis and spray drying was investigated to recover the salt. Salt extractive distillation – with salt recovery enabled by electrodialysis – was conceptually integrated in the fermentation broth-ethanol separation trains of corn and cellulosic ethanol facilities and investigated through process simulation with Aspen Plus® 2006.5 to reduce the recovery and purification energy demand of bioethanol. Experiments for the electrodialytic concentration of calcium chloride from high diluate concentrations, prevalent in the salt recovery process when calcium chloride is used as the salt separating agent in the salt extractive distillation of bioethanol, were carried out to determine the fundamental transport properties of an ion exchange membrane pair comprising commercially available membranes for implementation in the conceptual process designs. The maximum calcium chloride concentration achievable through electrodialytic concentration is 34.6 wt%, which is mainly limited by the water transport number. In case of corn-ethanol, retrofitted salt extractive distillation resulted in an energy demand reduction of about 20% and total annual cost savings on the order of MM$0.5 per year when compared with the state-of-the-art rectification/adsorption process for producing fuel ethanol from the beer column distillate. In case of cellulosic ethanol, salt extractive distillation with direct vapor recompression provided the highest energy savings of about 22% and total annual cost savings on the order of MM$2.4 per year when compared with the base case comprising conventional distillation and adsorption for recovering and purifying ethanol from the fermentation broth. Based on the conceptual process design studies, an overall maximum energy savings potential of 1.5*10[superscript]17 J or about 0.14 Quad (as natural gas higher heating value) per year could be estimated for the targeted 56.8 GL of corn-ethanol and 60.6 GL of cellulosic ethanol to be produced in the U.S in 2022 when salt extractive distillation enabled by electrodialysis is implemented in the fermentation broth-ethanol separation trains of the corn and cellulosic ethanol facilities.
9

Mitigating Transients and Azeotropes During Natural Gas Processing

Ebrahimzadeh, Edris 01 April 2016 (has links)
Cryogenic carbon capture process can be used to efficiently eliminate CO2 emissions from fossil-fueled power plants. The energy-storing embodiment of cryogenic carbon capture (ES-CCC) integrates energy storage with cryogenic carbon capture and uses natural gas as a refrigerant. ES-CCC captures CO2 from slowly varying or steady-state sources even as it absorbs and replaces large amounts of energy on the grid for energy storage. These large transients occur in the LNG generation as the process moves through energy storing to energy recovery operations. Additionally, raw natural gas often includes CO2 that forms an azeotrope with ethane. Breaking this azeotrope and separating CO2 from other hydrocarbons to meet natural gas pipeline and liquefied natural gas (LNG) standards is very energy intensive. The purpose of this work is to (a) describe a dynamic heat exchanger that reduces the heat exchanger performance and efficiency losses experienced under transient conditions and (b) introduce an alternative extractive distillation system for CO2 separation from ethane that requires less capital and has a lower operating cost than the conventional system for the same purification. This investigation demonstrates theoretically and experimentally that the dynamic heat exchangers can absorb sudden and large changes in flow rates and other properties without compromising either the heat exchanger efficiency or creating thermal or other stresses. These heat exchangers play an essential role in the ES-CCC process. Designs for retrofitting existing heat exchangers and for replacing existing heat exchangers with new designs are both theoretically and experimentally tested. The ES-CCC process requires natural gas processing to meet pipeline and LNG standards in many applications, depending primarily on the CO2 content of locally available NG. The energy, cost, and dynamic response of such processing hinges primarily on the most difficult step, breaking the CO2-ethane azeotrope. This project proposes and analyzes an alternative process for breaking this azeotrope and a control scheme that dramatically improves the dynamic response of natural gas processing plants, including steady and transient control scheme and processing simulations. These contributions to the ES-CCC capture process all have much broader applications in many chemical and energy processes. These contributions to ES-CCC and other industrial processes improve energy efficiency and dynamic performance of many processes and are ready for larger scale demonstration.
10

Redes Neurais Artificiais aplicadas ao controle inteligente de Colunas Extrativas. / Artificial Neural Networks applied to the intelligent control of Extractive Columns.

NEVES, Thiago Gonçalves das. 08 March 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-03-08T19:42:36Z No. of bitstreams: 1 THIAGO GONÇALVES DAS NEVES - DISSERTAÇÃO PPGEQ 2016..pdf: 9202960 bytes, checksum: bd716eca5d4f915809c1ee1d36838c10 (MD5) / Made available in DSpace on 2018-03-08T19:42:36Z (GMT). No. of bitstreams: 1 THIAGO GONÇALVES DAS NEVES - DISSERTAÇÃO PPGEQ 2016..pdf: 9202960 bytes, checksum: bd716eca5d4f915809c1ee1d36838c10 (MD5) Previous issue date: 2016-04-25 / CNPq / Em colunas de destilação, as rígidas especificações de qualidade do produto final exigem que o sistema de controle das colunas de destilação possua alto grau de desempenho. Nos casos em que ocorrem distúrbios na alimentação em colunas extrativas é muito difícil manter a composição do produto em seu valor referência, visto que, após o distúrbio, os setpoints dos controladores deixam de corresponder exatamente às especificações dos produtos. O presente trabalho teve como objetivo o desenvolvimento e a implementação de um Soft Sensor inteligente para fins de controle em uma coluna extrativa de produção de etanol anidro, usando o etilenoglicol como solvente. Para fazer a previsão dos novos setpoints diante perturbações, foi utilizado o conceito de Redes Neurais Artificiais, que se mostrou como uma solução rápida e viável. Os resultados mostraram que para a faixa de distúrbios considerada, o Soft Sensor foi capaz de prever a nova condição de regime, por meio da determinação inteligente dos novos setpoints de controladores presentes na instrumentação original da coluna. O controle apresentou desempenho satisfatório, mantendo o produto no topo e no fundo da coluna dentro das especificações. / In high purity distillation columns, the strict quality specifications of the final product require that the distillation columns control system have a high degree of performance. In cases where disturbances occur in the extractive columns feed, it is very difficult to maintain the composition of the product in its reference value, since, after the disturbance, the setpoints of the controllers fail to correspond exactly to the products specifications. The aim of this work is the development and implementation of an inteligent Soft Sensor for control purposes in an extractive column for anhydrous ethanol production, using ethylene glycol as solvent. To forecast the new setpoints before disturbance, the concept of Artificial Neural Networks was usesd, which proved to be a fast and feasible solution. The results showed that for range considered disturbances, the Soft Sensor was able to predict the new system condition, by intelligently determining the new setpoints of the controllers present in the original instrumentation of the column. The control showed satisfactory performance, keeping the products at the top and bottom of the column within specifications.

Page generated in 0.1617 seconds