Hydrogen recovery using membranes in methanol production process

Methanol is produced by employing the synthesis gas (syngas) generated from the natural gas or other fossil fuels based resources. Most of the commercial methanol synthesis re...eactors operate at high pressure with limited conversion that results in a large recycle stream to be recycled back to the reactor. However, due to the presence of inert and impurities in the process stream, a small fraction of recycled stream is purged to avoid the accumulation of inerts in the system. Since the hydrogen to carbon ratio in the syngas is usually kept higher than 2, the purge stream contains significant quantities of hydrogen which is lost in the fuel stream. In this study, we propose the conceptual design and development of an integrated process for the methanol production where the hydrogen recovery from the purge gas is done employing the membranes as shown in figure 1. The goal is the study the effect of recovering the hydrogen in the purge gas and recycling it back to the methanol reactor on the economics of the entire methanol plant. The main advantage from the new design is the recovery of useful hydrogen from the purge stream using membranes with no additional rotating equipments.