Economic, environmental, energy and exergy analysis and multi-objective optimization for efficient purification of a friendly gasoline additive by extractive distillation coupled with pervaporation

Abstract

Ethyl tert-butyl ether, an environmentally friendly gasoline additive, has high industrial application value, which is very necessary to study the refined process. The development of an efficient ternary azeotropic separation and purification process promotes the establishment of an environment-friendly society. In this study, two common methods of extractive distillation and extractive pressure swing distillation and three enhanced methods of heat integration process and coupled pervaporation technology were used to efficiently separate ethyl tert-butyl ether/ethanol/water. The most effective and environmentally friendly extractants were screened by analyzing the effects of relative volatility, intermolecular interactions and biotoxicity. The multi-objective optimization method was adopted to optimize the process with the annual total cost and gas emissions as the goals and the optimal parameters and process plans for extractive distillation and extractive pressure swing distillation were obtained. Finally, five technological processes are analyzed from the aspects of economy, environment, energy and exergy. It was found that the use of pressure swing distillation would greatly increase the economic and energy loss. And compared with the conventional process, the total annual cost of the extractive distillation coupled pervaporation process was reduced by 15.12 % and the environment was reduced by 20.17%. The coupling process that is of great significance to the purification of ethyl tert-butyl ether, an environmentally friendly gasoline additive was superior to the single distillation process in terms of economy, environment and energy.