Comparative study of conventional, reactive-distillation and pervaporation integrated hybrid process for ethyl tert-butyl ether production

Ethyl tert-butyl ether (ETBE) is widely used as an oxygenate additive to gasoline; however, a drawback in the conventional ETBE manufacture is the energy intensive product recovery process, making ETBE expensive. The purification process of ETBE involves the separation of ETBE, mixed C4 hydrocarbons and unreacted ethanol. The unreacted ethanol forms azeotropic mixtures with ETBE that are difficult to separate by distillation. In this work, a comparative study between the conventional process to produce ETBE and two alternative intensified processes is presented by means of process simulation in Aspen Plus. One of the alternative methods for improving the separation and purification section of ETBE is the use of a hybrid distillation-pervaporation process with alcohol-selective membranes, which allows to reach the target ETBE purity (95.2 wt%) with a lower energy consumption and at the same time the permeate stream, with a high ethanol content, is recycled back to the reaction section. Alternatively, the production of ETBE by means of reactive distillation is analyzed for the same basis of calculation. The results show that the reactive distillation allows a significant increase in the conversion of the reactants, but in contrast the energy consumption is higher than in the other processes evaluated.Financial support from the Spanish Ministry of Science under the projects CTM2013-44081-R (MINECO, Spain-FEDER 2014–2020), CTQ2015-66078-R and CTQ2016-75158-R is gratefully acknowledged. Adham Norkobilov also thanks the SILKROUTE Project for a PhD scholarship funded by the European Commission through the Erasmus Mundus Action 2 Programme

Energy efficient global optimisation of reactive dividing wall distillation column

This is the author accepted manuscript. The final version is avialable from Taylor & Francis via the DOI in this recordAn optimisation problem to minimise energy requirements in the synthesis of bio-additive ethyl tertiary butyl ether (ETBE) via reactive dividing wall distillation column (RDWC) is considered. The contribution of the article is to solve a real-world optimisation problem by addressing two challenges: (i) finding optimal process conditions in few numbers of simulations and (ii) handling mixed-integer variables. An efficient global optimisation algorithm is used to find optimal process conditions and adapted to handle both integer and continuous variables. ETBE is produced by the reaction of ethanol and isobutene in RDWC and has proven its niche in reducing the energy requirements for reaction–separation processes. However, the overall economics of the process is governed by the energy requirements. Therefore, it is crucial to find the optimal process conditions for achieving a cost-effective process. Reboiler duty of RDWC, considered as a measure of the energy requirements to be minimised by using the algorithm. Seven variables (four integers and three continuous) are used in the optimisation process to minimise the reboiler duty. A very low value of reboiler duty is obtained after doing the optimisation, which not only provides insight when using RDWC but also shows the potential of the algorithm used.Natural Environment Research Council (NERC

Kinetic studies of liquid phase ethyl tert-butyl ether (ETBE) synthesis using macroporous and gelular ion exchange resin catalysts

Ethyl tert-butyl ether (ETBE) synthesis from ethanol (EtOH) and tert-butyl alcohol (TBA) was studied with different macroporous and gelular ion exchange resin catalysts. Purolite® (CT-124, CT-145H, CT-151, CT-175 and CT-275) and Amberlyst® (15 and 35) ion exchange resins were used for the present work. Effect of various parameters such as catalyst type, temperature, reactants feed molar ratio and catalyst loading were studied for the optimisation of reaction condition. Among the catalysts studied, Purolite CT-124 gave better results for TBA conversion and selectivity towards ETBE. Kinetic modelling was performed with this catalyst and activation energy and water inhibition coefficient were determined. Heterogeneous kinetic models [e.g., Eley-Rideal (ER), Langmuir-Hinshelwood-Hougen-Watson (LHHW)] were unable to predict the behaviour of this etherification reaction, whilst the quasi-homogeneous (QH) model represented the system very well over wide range of reaction conditions

Preliminary Design of Reactive Distillation Columns

A procedure that combines feasibility analysis, synthesis and design of reactive distillation columns is introduced. The main interest of this methodology lies on a progressive introduction of the process complexity. From minimal information concerning the physicochemical properties of the system, three steps lead to the design of the unit and the specification of its operating conditions. Most of the methodology exploits and enriches approaches found in the literature. Each step is described and our contribution is underlined. Its application is currently limited to equilibrium reactive systems where degree of freedom is equal to 2 or less than 2. This methodology which provides a reliable initialization point for the optimization of the process has been applied with success to different synthesis. The production of methyl-tert-butyl-ether (MTBE) and methyl acetate are presented as examples

Modelling Of Reactive Distillation For The Production Of Methyl Tert-Butyl Ether (MTBE) Parametric Sensitivity Study On Kinetic Model

Modelling of reactive distillation for the production of MTBE has been presented in this thesis. A reactive distillation column modelled by using RADFRAC module in the Aspen Plus V10 software for the production of MTBE. The simulation was done on an equilibrium basis. Prior to running the simulation, all the necessary data were collected. The kinetic data which is the coefficients of the equilibrium equation were collected from the equilibrium equation. The values obtained were 357.094, -1492.77, -77.4002 and 0.507563. These values were entered into the Aspen Plus V10 built-in Keq expression. The simulated model was verified by comparing to the published data. Once it was verified, the simulation was then used to carry out parametric sensitivity study on kinetic model. The effect of changes in the kinetic data and four different operating conditions of choice such as the feed flowrate of methanol, the feed flowrate of mixed butenes, the reflux ratio and the composition of isobutylene on the simulation results in terms of MTBE purity and isobutylene conversion were studied in detail. The individual best values for each operating conditions were determined. Then optimization carried out. The optimized values were 209.3 mol/s for methanol feed flowrate, 583.2 mol/s for mixed butenes feed flowrate, 7 for reflux ratio and 0.357 for isobutylene mole fraction. From these set of values, a MTBE purity and isobutylene conversion of 100.00 % obtained successfully. This study shows that the changes in parameters influences the performance of reactive distillation process for the production of MTBE

Steady State Multiplicity In The Reactive Distillation Of Methyl Tert-Butyl Ether (MTBE) Synthesis: Stability Analysis

Reactive distillation (RD) has garnered a lot of attention due to its tremendous potential for process intensification. Due to that, the methyl tert-butyl ether (MTBE) synthesis in reactive distillation (RD) column was studied and an equilibrium model was developed by using Aspen Plus V10. The proposed model was validated by comparing the simulation results with the published simulation results from the literature. The model obtained high isobutene conversion and MTBE purity for heterogenous catalyzed system, which is desirable in the industrial MTBE production process. The comparisons on temperature profiles and liquid composition profile of RD column also yielded promising results. The proposed model can be used as a tool for the analysis of multiple steady state in RD column of MTBE. It is concluded that only single steady state of MTBE synthesis that can be found when using the same column configuration in Aspen Plus V10. Sensitivity analysis is conducted to study the influence of reflux ratio on the isobutene conversion. From this analysis, it was shown that MTBE purity and isobutene conversion were maximum at reflux ratio of 7. Stable reactive distillation of MTBE can be achieved since the equilibrium modelling has developed higher steady state solution

Simulation Of Reactive Distillation Column Of Methyl Tert- Butyl Ether Production

Reactive distillation is an efficient technique of combination of both reaction and separation in a single unit beneficial for equilibrium-limited reactions, cost-effective , reduce energy and improvement purity of the product. The usage of reactive distillation column has increased attention because of its high potential for process intensification and therefore this process needs to be studied fully so that the reaction conversion and purity of the product are assured before its implementation in industrial scale. In this work, Aspen Plus was used for simulation of reactive distillation column where methanol and butene undergo esterification reaction to produce Methyl tert-butyl ether (MTBE) and undergo continuous separation process. Firstly, the results are compared for both literature and simulation studies. The simulated results obtained by Aspen Plus showed that it is acceptable range since the simulation values obeyed that of the literature with a purity errors of top and bottom for MTBE is 0.0048% and 0.0026% respectively. In addiction, simulation results have been performed for sensitivity analysis. Sensitivity analysis on the same RadFrac model showed that reflux ratio of 7, number of reactive stages at 10, and reboiler of 11.45 have significant effects on met MTBE purity. Sensitivity analysis conducted shows that the MTBE purity were maximum at reflux ratio 7. The best feed location for butene at stage 3 while methanol feed at stage 12

Simulation Study on Operations Aspects of a Reactive Distillation Column for Production ofEthyl Acetate Using ASPEN PLUS™ and ASPEN DYNAMIC™

Ethyl acetate is a widely used organic compound in manufacturing of printing inks, paints, coatings, perfume, film, food additives, pharmaceutical and others due to its low boiling point. There were numerous research carried out in different areas related with ethyl acetate production. In recent years, due to the increasing trend in ethyl acetate demand, reactive distillation that combined reaction process and distillation process technique has been used for ethyl acetate production studies. However, most of the researchers focus on column configuration and control of the column. There are limited studies being carried out on starting up a reactive distillation column in dynamic simulation