Fuel additives production: ethyl-t-butyl ether, a case study

The students frequenting the program Chemical Engineering at the Department of Chemical and Environmental Engineering, Faculty of Chemical and Food Technology of the Slovak University of Technology in Bratislava are taught to be able to combine and develop their knowledge acquired in the area of chemical, energetic, environmental, and safety engineering. Prior to completing their study, they are obliged to develop a report regarding engineering, economic, and safety analysis of important chemical technology. This paper presents the most valuable outputs of the student’s Technology project aimed on simulation and optimization of the fuel additives production technology. 2-Ethoxy-2-methylpropane (ethyl-t-butyl ether, ETBE) production based on liquid-phase etherification of 2-methylpropene with ethanol in the presence of heterogeneous catalyst was studied. Different patented technologies were investigated in terms of their profitability and safeness. The first technology was an isothermal reactor with the product separation via distillation (Kochar & Marcell, 1981). The next ETBE production design assumed was a modification of the previous one; the product separation was carried out using liquid-phase extraction (Pucci et al., 1992). The last design considered in this study was a reactive distillation column with a pre-reactor (Bakshi et al., 1992). In all three technologies, etherification reaction was carried out using Amberlyst ion-exchange resin in its H+ form as the catalyst. Selected ETBE production designs were simulated using Aspen+ program. Their profitability was compared on basis of the investment and operation costs assessment taking into account both the produced ETBE yield and purity. Further, basic safety analysis of all chosen technologies was performed in order to identify possible hazards. Finally, individual and social risk connected with the plant operation was computed. Taking into account these economic and safety criteria, the best alternative for ETBE production was the reactive distillation.