Comparative techno-economic analysis of a directly coupled production of methanol and formalin as example for improved hydrogen management in the chemical industry

In the context of carbon–neutral production, sustainable H 2 will become a crucial resource and key element for the transformation of the chemical industry. In this study, the potential of inter-plant H 2 networks is demonstrated in the context of methanol and its derivatives. In order to assess the impact of the exploitation of untapped H 2 -rich waste streams, a process chain for the directly coupled production of CO 2 -based methanol and formaldehyde was chosen. It is shown that including a H 2 loop between a modified silver catalyst processes for formaldehyde production and the feed stream of CO 2 -based methanol synthesis results in an increase in process performance as well as economic benefits. Directly coupled production leads to utilization ratios of 98% and 99% for CO 2 and H 2 , respectively, while exergy efficiencies are improved by up to 4.5%pt. Economic evaluation shows that improved H 2 management not only yields savings in operational expenditures but also lowers capital investments. Over a wide range of assumed H 2 prices, small decentralized plants become more competitive when both subprocesses are directly linked. Minimum selling prices between 836 €·t −1 and 852 €·t −1 are reached for methanol in integrated plants, corresponding to a decrease of 3 to 13.5%pt when compared to separately operated CO 2 -based methanol synthesis followed by conventional formaldehyde production.