Optimal integration of methanol-to-gasoline process with organic Rankine cycle

Methanol-to-gasoline (MTG) process is an important modern technology for fuel production. As a process featured in redundant heat, with reaction temperature sometimes up to 380, so far MTG heat integration has not been discussed in detail to make MTG an electricity generator. This paper, in this context, proposes a novel superstructure of the integration of methanol-to-gasoline (MTG) process with organic Rankine cycle (ORC) in the hope of higher energy efficiency. To simultaneously optimize the flowsheet structural, the working fluid and operating condition of the novel superstructure of ORC-MTG integrated process, genetic algorithm (GA) is performed based on economic criteria through MATLAB coupled with Aspen Plus. With Propylbenzene-R601 the most favorable working fluid pairs in ORC. Compared with the current industrial counterpart process, the optimal ORC-MTG integrated process saves cooling water by 18.77% with the ROI at 22.66%. The thermal efficiency of 18.3% is valuable for the industrial application, which suggests the significance of introducing ORC to other heat-rich industrial plants requiring higher energy efficiency, especially in the case of expensive electricity. (C) 2019 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.