Performance Requirements of Membrane Reactors for the Application in Renewable Methanol Synthesis: A Techno-Economic Assessment

Renewable energy carriers are expected to play a key role in the defossilization of the energy and chemical sector. For renewable methanol synthesis, membrane reactors (MR) have been tested on a laboratory-scale with promising results. However, membrane performance requirements that allow an economic benefit for their large-scale deployment are missing. Therefore, a 1D Python MR model is coupled with an AspenPlus process simulation to conduct a techno-economic assessment with focus on membrane performance. Two synthesis loop configurations are investigated: one where feed and sweep recycle are operated at the same pressure and one where the sweep recycle operates at atmospheric pressure. The results show that both configurations can offer technical benefits, if sufficiently high product separation can be achieved, but that for a compressed sweep recycle no economic benefits are possible. As a consequence, membranes used for methanol synthesis must endure operation at high pressure differences, Furthermore, the results highlight the critical role of the H-2 permeance, which should remain below 1 x 10(-9) mol m(-2) s(-1) Pa-1. From an economic standpoint high water permeation has a more beneficial effect than high methanol permeation.