Alcohol composition dependent design of an efficient multi-etherification reactive distillation system

Abstract

This study aimed to design energy-efficient systems of reactive distillation for the simultaneous production of methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) from mixed feeds of methanol and ethanol. The first design is the individual production of two ethers where two reactive distillation columns were proposed for the production of each ether after feed alcohol separation while the co-production system of both ethers was introduced in a single reactive distillation column without the alcohol separation. Rigorous Simulations of the two proposed systems were conducted with the varying ratios of two alcohols occurring in actual process streams. When the amount of methanol was higher than ethanol, the co-production system exhibited better performance than the individual ether production system since the temperature inside the alcohol separation column was lower, resulting in a lower relative volatility of methanol and an increased heat duty in the alcohol separation column. Contrarily, when the amount of ethanol was higher than methanol, the individual production system showed better performance than the co-production system due to the unfavorable reaction equilibrium of ETBE production, causing a high internal flowrate in the co-production RD column. The external heat exchanger was introduced to the individual production system and co-production system, leading to decline in the reboiler utility consumption. Consequently, heat integrated system shows enhanced performance compared to the system which is not heat integrated.