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Distillation Processes (distillation + process)
Selected AbstractsEvaluation of a simple batch distillation process for treating wastes from metalworking industriesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2004P Cañizares Abstract A simple batch distillation process for the treatment of two types of industrial waste generated in a metalworking factory has been evaluated. Both types of waste are oil-in-water emulsions composed of numerous compounds and each type has a high content of water-soluble species. The water-soluble nature of the wastes precludes the use of conventional treatment technologies, such as ultrafiltration or chemical emulsion breaking, since they need to be complemented with additional treatment processes that would probably increase the cost considerably. A simple characterization of the liquid,vapour equilibrium and a scale-up study has demonstrated the applicability of this technology. The process allows 90% of the waste to be recovered as water, thus achieving the required quality limits for discharge into a municipal wastewater treatment plant. An approximate estimation of capital investment and operating costs for an existing case has shown the economic viability of this process. Copyright © 2004 Society of Chemical Industry [source] Transesterification of dimethyl oxalate with phenol over TiO2/SiO2: Catalyst screening and reaction optimizationAICHE JOURNAL, Issue 12 2008Xia Yang Abstract Physicochemical properties of silica-supported titanium oxide catalysts as well as their performances for transesterification of dimethyl oxalate (DMO) with phenol to methyl phenyl oxalate (MPO) and diphenyl oxalate (DPO) have been investigated systematically. Various wt % of TiO2 were loaded on SiO2 by a two-step wet impregnation method. The surface properties of TiO2/SiO2 catalysts were explored by various characterization techniques (BET, SEM, ICP, XPS, XRD, FTIR of pyridine adsorption, and NH3 -TPD). Catalytic performances of TiO2/SiO2 catalysts were found to be strongly dependent on TiO2 dispersion and surface acidity. Monolayer dispersion capacity of TiO2 on silica was estimated to be about 4.0 TiO2 molecules per nm2 (SiO2) and no crystalline TiO2 was detected at TiO2 loading less than 12 wt %. FTIR and TPD analysis suggested that weak Lewis acid sites on the surface of TiO2/SiO2 were responsible for their unique selectivity to the target products, MPO and DPO. An optimization of reaction conditions for the transesterification of DMO with phenol was performed over 12 wt % TiO2/SiO2 calcined at 550°C. In addition, we studied the disproportionation reaction from MPO to DPO via a catalytic distillation process, which is highly efficient to promote formation of the desired DPO. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] The Benefits of Sunflower Oleodistillate (SOD) in Pediatric DermatologyPEDIATRIC DERMATOLOGY, Issue 6 2009Lawrence F. Eichenfield M.D. In its natural state, the oil contains high levels of essential fatty acids, particularly linoleic acid, which has skin barrier-enhancing properties. A sunflower oleodistillate (SOD), which is produced through a molecular distillation process without the use of solvents, has been shown to increase the epidermal key lipid synthesis and to reduce inflammation in vitro and in animal models. It has also been shown to activate peroxisome proliferative-activated receptor-, (PPAR-,) in vitro. As PPAR-, agonists have been shown to stimulate keratinocyte differentiation, improve barrier function, and enhance lipid metabolism in the skin, it has been suggested that SOD might also be efficacious in atopic dermatitis (AD). An initial clinical evaluation of the care effect of a 2% SOD emulsion in 20 adult volunteers with atopic skin revealed the moisturizing properties of SOD. Finally, a strong steroid-sparing effect and a positive effect on quality-of-life parameters were clearly demonstrated for the 2% SOD cream in studies in infants and babies with AD. [source] Analysis of a concept for predicting missing group interaction parameters of the UNIFAC model using connectivity indicesAICHE JOURNAL, Issue 6 2009André Mohs Abstract The reliability of a method for the determination of missing group interaction parameters for the UNIFAC model1 proposed by Gani et al.2 was carefully examined. In this method, called CI-UNIFAC, the missing group interaction parameters are determined by means of connectivity indices. Such a method would be very desirable since it would save a lot of time and money spent for measuring VLE data to fill the gaps in the UNIFAC parameter matrix. Because of the great importance of distillation processes for the chemical industry mainly the results for vapor-liquid equilibria (VLE) were investigated using the data stored in the Dortmund Data Bank and VLE data measured. There are examples in which the method works quite well, but often the procedure leads to poor results. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] A generic feasibility study of batch reactive distillation in hybrid configurationsAICHE JOURNAL, Issue 5 2009C. Stéger Abstract A new graphical feasibility method is developed to investigate batch reactive distillation processes in middle vessel column. The suggested methodology can deal with fully reactive, nonreactive, and complex column configuration. A new formulation is suggested to describe the composition profiles in the reactive sections. Its application has made possible to develop a generic feasibility methodology containing the same model equations independently of the presence or absence of reaction. By combining the reactive and nonreactive models, not only the fully reactive and fully nonreactive but also hybrid configurations can be studied. Feasibility criteria related to the hybrid configurations are also presented. Application of the new methodology is demonstrated on the production of ethyl acetate in batch reactive distillation. Five configurations are found feasible; pure EtOAc is produced as distillate, and pure H2O is produced at the bottom. In each case, continuous feeding of AcOH is necessary. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Graphical design applied to MTBE and methyl acetate reactive distillation processesAICHE JOURNAL, Issue 6 2001Jae W. Lee Graphical tray-by-tray methods for reactive distillation columns we developed previously are extended to study two industrial processes: MTBE production and methyl acetate production. As both processes involve four components, projection was used to obtain ternary diagrams by ignoring the inert (n-butane) for MTBE production and by projecting onto planes of constant acetic acid concentrations for methyl acetate production. These projected methods clearly explain the placing that industry uses for the reaction zones in these processes. Further, it can be visualized why there is an optimum reflux ratio for the methyl acetate process and a value can be quantitatively predicted for it that lies within the range the literature reports. [source] Molecular and macroscopic modeling of phase separationAICHE JOURNAL, Issue 10 2000Fernando A. Escobedo Recently proposed pseudoensemble Monte Carlo methods are extended in this work to map out diverse phase diagrams (projections of the phase-coexistence hypersurface) of multicomponent mixtures required to characterize fluid-phase equilibrium phenomena and to design separation processes. Within the pseudoensemble framework, the macroscopic models of different equilibrium processes can be readily integrated to the mathematical constraints that specify the thermodynamic state of the system. The proposed Monte Carlo methods allow, for example, the simulation of isopleths and cloud-point lines to compare experimental to simulation data and to test molecular force fields. Applications of this approach include the study of retrograde phenomena in a model natural-gas mixture through simulation of dewlines and coexistence lines at constant vaporization fraction. As demonstrated, pseudoensemble simulations can also be used to generate the thermodynamic data necessary to solve problems encountered in continuous and discontinuous distillation processes. [source] Regular and inverted batch process structures for pressure swing distillation: a case studyASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2009Andreas Klein Abstract The main focus of this paper is on the comparison of the inverted and the regular pressure swing batch distillation processes for the separation of a homogenous azeotropic mixture. On the basis of a successful, experimentally validated rigorous model, a simulation study to identify the differences between the two processes and the influences of different structures on them is carried out. This identification of influences helps in finding out a heuristic base of the most suitable batch structure for a given separation problem. Especially the influence of the feed flow rate on the processes and the differences between the results on operation with different pressures will be addressed. Furthermore advantages, disadvantages and the limitations of both processes will be shown. In the end the best way of operating the pressure swing batch distillation will be presented depending on the product purity and the feed concentration for a given example. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Environmental performance of lignocellulosic bioethanol production from Alfalfa stemsBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 2 2010Sara González-García Abstract A ,well-to-wheel' analysis was conducted for bioethanol obtained from alfalfa stems by means of the Life Cycle Assessment (LCA) methodology. This analysis was compared with two blends of conventional gasoline with bioethanol (E10 and E85), all used in a mid-size car. A biochemical process including enzymatic hydrolysis and simultaneous saccharification and fermentation was considered. The life cycles of the fuels include gasoline production, alfalfa agriculture, lignocellulosic bioethanol production, blend production, and finally the use of fuels. The production of the alfalfa plant has two products: high-protein leaves for animal feed (the main driving force) and high-fiber stems. In this study, we assumed two allocation procedures based on mass and protein content, the latter reflecting the greater value of the leaves. According to the results, the use of bioethanol-based fuels leads to reduced global warming potential. A reduction in fossil fuel extraction of up to 72% could be achieved when pure bioethanol is used as transport fuel. On the contrary, bioethanol fuels are not the most suitable option when assessing acidification, eutrophication, and photochemical oxidant formation impact categories, mainly due to the higher impact from the upstream processes (specifically agricultural activities). LCA methodology helped to identify the key areas in the bioethanol production where researchers and technicians need to work to improve the environmental performance, paying special attention to enzyme production, onsite energy generation and distillation processes as well as agricultural activities. Copyright © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd [source] A Study on Modern High Effective Random Packings for Ethanol-Water RectificationCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 7 2008S. Darakchiev Abstract Raschig Super-Ring is a modern and high-efficient packing used for intensification of absorption and distillation processes. The aim of this work is to characterize the efficiency of this packing applied to rectification of an important industrial system, ethanol-water, and to compare its efficiency to that of some random packings of the third generation as well as to the structured packing, HOLPACK, which is used in the ethanol production industry. The experiments were carried out in a column installation, 0.213,m in diameter with a packing height of 2.8,m. The column is heated by a number of electrical heaters (total power 45,kW), which can be switched gradually. Operation at total and partial reflux is possible. Eight types of random packings were studied: five types of Raschig Super-Ring, four metallic (with characteristic dimensions 0.5, 0.6, 0.7, and 1") and one of plastic material 0.6"; two types of packing IMTP and one plastic Ralu Flow. Some experiments were conducted at total reflux operation at vapor velocity, 0.253,0.936,m/s, and liquid superficial velocity, 4.44,·,10,4,1.63,·,10,3,m3/(m2s). Experiments at partial reflux were carried out at constant liquid superficial velocity and changeable vapor velocity as well as at constant vapor velocity and changeable liquid velocity. The results are presented as height of transfer unit, HTU, and height equivalent to a theoretical plate, HETP, as a function of the velocity of phases. [source] | ||||||||||