Optimization of Operation and Design of a Multi-Energy System for the Production of Low-Carbon Methanol

Abstract

Methanol is one of the key feedstocks in the chemical industry and seen as a potential synthetic fuel replacement for maritime and air transport. Currently, most methanol is produced via the steam reforming of natural gas, resulting in significant greenhouse gas emissions. Sustainable methanol, on the other hand, can be produced via multiple path- ways, each resulting in different energy and capital requirements, as well as CO2 emissions. This research integrates these different pathways in the context of a multi-energy system and linearly optimizes the design and operation of that system to analyse which path- way is preferred for the industrial cluster of Rotterdam in terms of associated costs and emissions per produced tonne of methanol. In this research, an assessment is made on the effect of (i) including and excluding a CO2 storage facility, (ii) the type and origin of biomass and (iii) the steam biomass ratio in the biomass gasification routes on the optimal design of the multi-energy system. It is found that the inclusion of a CO2 storage facility significantly improves the optimal design of the multi-energy system in terms of both costs and emissions, making it even possible to obtain negative emissions with only minor cost increases. In this design, the preferred methanol production method is a biomass gasification method that includes CO2 capture. Regarding the type of biomass it is found that biomass from close by is preferred due to lower costs and emissions associated with transport. Finally, a low steam biomass ratio is preferred; the lower biomass consumption at higher steam biomass ratios does weigh up against its higher steam consumption in terms of both costs and emissions