Assessment of an integrated renewable-based hydrogen, methanol and dimethyl ether production system for sustainable fuels

Abstract

Hydrogen, which is considered a critical feedstock in alternative fuel production, offers a competitive alternative to fossil-fuel-based technologies. During this transition, carbon capture technologies are essential to ensure sustainable energy. This work proposes and analyzes the performance of a combined power-to-liquid system powered by solar and wind electricity. The carbon dioxide used is captured from refinery flue gas through the post-combustion capture process utilizing the monoethanolamine (MEA) solvent, and the purified carbon dioxide and green hydrogen are used to synthesize methanol, and subsequently produce dimethyl ether (DME). The applicable products obtained are hydrogen, methanol, DME, and electricity. Through a chemical interaction with carbon dioxide extracted from flue gas, hydrogen produced by the alkaline electrolyzer is transformed into methanol. Dimethyl ether is synthesized by dehydration of the methanol obtained. The Aspen Plus is used to create and assess the integrated process. When monthly renewable electricity production is assessed, May has the lowest, and July has the highest output. Based on the electricity available, the rates of hydrogen and methanol are evaluated; the results show that the hydrogen production capacity is 34.59 kg/h, the methanol production capacity is 56.95 kg/h, and the dimethyl ether production capacity is 28.66 kg/h. The system's overall energy and exergy efficiency values are 33.45 % and 32.58 %, respectively. Moreover, some parametric studies are carried out to evaluate how system parameters, such as electrolyzer temperature, affect process efficiencies.