Incorporation of diethyl ether production to existing bioethanol process: Techno-economic analysis

Abstract

The decline of bioethanol consumption can jeopardize the future of bioethanol producers. This research aims to design the conversion process of ethanol into a more versatile and valuable product, e.g., diethyl ether (DEE). To produce DEE, two types of ethanol can be utilized. Previously, the anhydrous ethanol was tested experimentally via catalytic dehydration on the Ru-HBZ catalyst. Satisfactory results were obtained, particularly acetaldehyde was not formed in the reaction. Herein, the catalytic experiment is extended using hydrous ethanol as feed resulting in an observable amount of acetaldehyde. These experimental results are implemented in the design of DEE production processes. Three production cases are investigated including the utilization of the anhydrous ethanol (Case I) and the utilization of the hydrous ethanol (Cases II and III). The most profitable process is obtained in Case I with the pay-out period of 4 years and % IRR (percentage of internal rate of return) of 55%. Acetaldehyde appears problematic in the DEE purification in Case II – the process is not profitable if distillation is selected for acetaldehyde removal. By implementing adsorption for the acetaldehyde removal, the process in Case III becomes profitable which is comparable to Case I. In addition, about a 5% reduction in the CO2 emission and a 7% gain in the energy utilization efficiency are observed in Case III. Finally, the utilization of hydrous ethanol (Case III) can be more attractive when the difference in selling prices of the hydrous and the anhydrous ethanols is more than 50%.