scholarly journals Reactive Distillation for the Production of Cyclohexanol

2021 ◽  
Vol 34 (4) ◽  
pp. 223-232
Author(s):  
Dahai Sun ◽  
Hui Tian ◽  
J. Sun ◽  
W. Xu

Cyclohexanol is an organic chemical intermediate product widely used in chemical<br /> industry and commonly produced by cyclohexene hydration. Because of the low mutual<br /> solubility of cyclohexene and water, the reaction is limited by chemical equilibrium,<br /> which has the disadvantage of low conversion of cyclohexene. In this paper, the hydration reaction of cyclohexene catalysed by A-36 cation exchange resin catalyst was analysed by Aspen Plus V8.6 simulation software in the presence of isophorone as cosolvent.<br /> The process model of synthesising cyclohexanol by catalytic distillation was verified by<br /> process experiments. The simulation experiments were carried out using the process<br /> model, and suitable operating conditions of the catalytic distillation column were obtained. These are: ketene feed ratio 1.5, alkene/water ratio 0.5, distillation stage trays 5,<br /> reaction stage trays 12, stripping stage trays 6, cyclohexene feed at the 18th tray, water<br /> and isophorone feed at the 5th tray, reflux ratio 3, feed ratio (D/F) 0.25. Under these<br /> operating conditions, the conversion of cyclohexene can reach 40.63 %.

Author(s):  
B Saha ◽  
H T R Teo ◽  
A Alqahtani

With ever-growing environmental concerns, petrochemical and fine chemical industries face an omnipresent issue in recovering dilute acetic acid from its aqueous solutions. Catalytic distillation holds an ascendancy over conventional physical separation methods such as distillation and extraction. Distillation is associated with the high costs involved in vaporising the more volatile water that exists in high proportions and possesses a high latent heat of vaporisation. Extraction is limited in view of the distribution of the components in the reacting system. The implementation of catalytic distillation reduces capital and operating costs, and allows for a wider range of operating conditions. Catalytic distillation is receiving increasing attention and holds a huge potential for the recovery of acetic acid. Through the application of catalytic distillation via the reaction of acetic acid with iso-amyl alcohol, a useful ester in the form of iso-amyl acetate could be produced.In the present work towards further process development, the synthesis of iso-amyl acetate via reactive distillation is studied using Katamax® catalyst packing in the catalytic reactive section. The reactive distillation experiments were carried out at laboratory scale in a 50 mm diameter column with a catalytic packing section of 1 m and non-reactive packed enriching and stripping sections of about 1 m each. A cation exchange resin catalyst, Purolite® CT-175, was used. The experiments were conducted with the aim of achieving an optimum column configuration as well as process conditions for the synthesis of iso-amyl acetate in a reactive distillation column (RDC). Several variants of the RDC set-up e.g. total feed mole ratio, reflux ratio, location of feed points, reflux configuration and acid concentrations were explored for the recovery of dilute acetic acid and to achieve a high purity value added product, iso-amyl acetate.


2013 ◽  
Vol 675 ◽  
pp. 196-199
Author(s):  
Yuan Di Zhang ◽  
Gang Xie ◽  
Yan Qing Hou

The new two-tower process of thrichlorosilane distillation consisting of removal of light components after removing heavy components is analyzed by assistant of a chemical process simulation software. In order to achieve lower energy consumption, the parameters for each tower in the new process are optimized, such as the number of theoretical plates, the position of feed plate, reflux ratio and distillate (bottoms) to feed ratio. The results show that the optimum parameters for the first tower are the number of theoretical plates of 32, the position of feed plate of 24, reflux ratio of 2.5 and the distillate to feed ratio of 0.8516. For the second tower, the number of theoretical plates, the position of feed plate, the reflux ratio and the bottoms to feed ratio are 80, 16, 143 and 0.9652 respectively. Applying the optimized results in practical production, mass fraction of PCl3 in overhead of the first tower is reduced by two orders of magnitude, condenser duty and reboiler duty of the second tower are dropped by more than eight percent while obtaining higher purity trichlorosilane products.


2015 ◽  
Vol 723 ◽  
pp. 629-632
Author(s):  
Ji Quan Liu ◽  
Peng Wang

The process for production high-purity methylal, which used methanol and formalin in the presence of cation-exchange resin catalyst, was investigated in the reactive and extractive distillation column. Effect of feed mole ratio of formaldehyde in the extracting and reacting section, molar ratio of methanol and formaldehyde, reflux ratio on the content of methylal in the distillate were investigated. The results show that the purity of methylal can reach 99.1% under the optimum conditions.


TAPPI Journal ◽  
2014 ◽  
Vol 13 (8) ◽  
pp. 65-78 ◽  
Author(s):  
W.B.A. (SANDY) SHARP ◽  
W.J. JIM FREDERICK ◽  
JAMES R. KEISER ◽  
DOUGLAS L. SINGBEIL

The efficiencies of biomass-fueled power plants are much lower than those of coal-fueled plants because they restrict their exit steam temperatures to inhibit fireside corrosion of superheater tubes. However, restricting the temperature of a given mass of steam produced by a biomass boiler decreases the amount of power that can be generated from this steam in the turbine generator. This paper examines the relationship between the temperature of superheated steam produced by a boiler and the quantity of power that it can generate. The thermodynamic basis for this relationship is presented, and the value of the additional power that could be generated by operating with higher superheated steam temperatures is estimated. Calculations are presented for five plants that produce both steam and power. Two are powered by black liquor recovery boilers and three by wood-fired boilers. Steam generation parameters for these plants were supplied by industrial partners. Calculations using thermodynamics-based plant simulation software show that the value of the increased power that could be generated in these units by increasing superheated steam temperatures 100°C above current operating conditions ranges between US$2,410,000 and US$11,180,000 per year. The costs and benefits of achieving higher superheated steam conditions in an individual boiler depend on local plant conditions and the price of power. However, the magnitude of the increased power that can be generated by increasing superheated steam temperatures is so great that it appears to justify the cost of corrosion-mitigation methods such as installing corrosion-resistant materials costing far more than current superheater alloys; redesigning biomassfueled boilers to remove the superheater from the flue gas path; or adding chemicals to remove corrosive constituents from the flue gas. The most economic pathways to higher steam temperatures will very likely involve combinations of these methods. Particularly attractive approaches include installing more corrosion-resistant alloys in the hottest superheater locations, and relocating the superheater from the flue gas path to an externally-fired location or to the loop seal of a circulating fluidized bed boiler.


2014 ◽  
Vol 983 ◽  
pp. 288-291
Author(s):  
Guo Lei Zhang ◽  
Xiang Dong Jin ◽  
Zhan Zhao ◽  
Zhi Jun Shi

To study of Nuclear power simulation software's basic functions and mathematical model based on thermal analysis. Describes the two-phase flow model of GSE software superiority, as well as the software optimization program .Use of software tools for normal operating conditions of the simulation calculation and analysis of the results. Comparison with design data shows that,the software use in marine nuclear power two loop system simulation analysis field, the accuracy of it is higher.


Author(s):  
Eric Liese

A dynamic process model of a steam turbine, including partial arc admission operation, is presented. Models were made for the first stage and last stage, with the middle stages presently assumed to have a constant pressure ratio and efficiency. A condenser model is also presented. The paper discusses the function and importance of the steam turbines entrance design and the first stage. The results for steam turbines with a partial arc entrance are shown, and compare well with experimental data available in the literature, in particular, the “valve loop” behavior as the steam flow rate is reduced. This is important to model correctly since it significantly influences the downstream state variables of the steam, and thus the characteristic of the entire steam turbine, e.g., state conditions at extractions, overall turbine flow, and condenser behavior. The importance of the last stage (the stage just upstream of the condenser) in determining the overall flowrate and exhaust conditions to the condenser is described and shown via results.


2016 ◽  
Vol 78 (8-3) ◽  
Author(s):  
Aliyu Bello A. ◽  
Arshad Ahmad ◽  
Adnan Ripin ◽  
Olagoke Oladokun

The moisture contents of powders is an important parameter that affects the quality and commercial value of spray dried products. The utility of predicted moisture content values from two droplet drying models were compared with experimental data for spray dried pineapple juice, using the Ranz-Marshal and its modified variants for the heat and mass transfer correlations. The droplet Diffusion model, using the Zhifu correlation, gave estimates with errors of about 8% at 165 oC, 9% at 171 oC, 26% at 179 oC and 2% at 185 oC. The Ranz-Marshal correlation also gave comparable results with this model while results using the Downing and modified Ranz-Marshall correlations widely diverged. The Energy balance model predicted completely dried juice particles, and short drying times, in contrast to the experimental data. The small error sizes of the Diffusion model improves on the wide error sizes of an earlier process model, making is useful as a first approximation choice, for spray drier design and simulation, especially for juices under comparable operating conditions.


Author(s):  
Patrick W. Wilkerson ◽  
Andrzej J. Przekwas ◽  
Chung-Lung Chen

Multiscale multiphysics simulations were performed to analyze wirebonds for power electronic devices. Modern power-electronic devices can be subjected to extreme electrical and thermal conditions. Fully coupled electro-thermo-mechanical simulations were performed utilizing CFDRC’s CFD-ACE+ multiphysics simulation software and scripting capabilities. Use of such integrated multiscale multiphysics simulation and design tools in the design process can cut cost, shorten product development cycle time, and result in optimal designs. The parametrically designed multiscale multiphysics simulations performed allowed for a streamlined parametric analysis of the electrical, thermal, and mechanical effects on the wirebond geometry, bonding sites and power electronic device geometry. Multiscale analysis allowed for full device thermo-mechanical analysis as well as detailed analysis of wirebond structures. The multiscale simulations were parametrically scripted allowing for parametric simulations of the device and wirebond geometry as well as all other simulation variables. Analysis of heat dissipation from heat generated in the power-electronic device and through Joule heating were analyzed. The multiphysics analysis allowed for investigation of the location and magnitude of stress concentrations in the wirebond and device. These stress concentrations are not only investigated for the deformed wirebond itself, but additionally at the wirebond bonding sites and contacts. Changes in the wirebond geometry and bonding geometry, easily changed through the parametrically designed simulation scripts, allows for investigation of various wirebond geometries and operating conditions.


2012 ◽  
Vol 263-266 ◽  
pp. 444-447
Author(s):  
Jin Nan Chen ◽  
Yu Chun Zhang ◽  
Xing Yong Sun

The software of the catalytic distillation process of methyl tertiary butyl ether was developed by using Process Simulation System Platform. The isobutylene conversion rate was calculated by using the catalytic distillation software. The relative error of isobutylene conversion rate between the simulation results and the design data from the China Petroleum Hohhot Petrochemical Co. was less than 5%. The relative error satisfies industrial design requirements. At present, enterprise workers use this software to learn how to operate the catalytic distillation process. The catalytic distillation software is further used to study the influence of reaction temperature and reflux ratio on the isobutylene conversion rate which can be used for future empirical model development and control studies.


2006 ◽  
Vol 6 (2) ◽  
pp. 82
Author(s):  
Iwan Harsono ◽  
Herman Hindarso ◽  
Nani Indraswati

It has been long recognized that emulsion polymerization is a complex heterogeneous process involving transport of monomers and other species and free radicals between aqueous phase and organic phases. Though there are a number of models available in the literature, most of them deal only with specific aspects in emulsion polymerization and are far from being general. To simulate this complicated process and to achieve an adequate level of understanding, a Polymer Plus' software from Aspen Technology, Inc. has been used. The objective of this work is to illustrate the principle use of Polymers Plus' and to simulate and analysis the free-radical seeded emulsion copolymerization of styrene-butadiene process model in a semi-batch reactor. The base case simulation can be used to gain process understanding by analyzing how process variables and operating conditions during the course of a semi-batch reactor affect product quality.


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