Modelling and Optimization of an intensified water electrolysis integrated tri-reforming coupled methanol production process

Mitigating greenhouse gas emissions (GHG) is a crucial global endeavour due to its significant impact on climate change. Fossil fuel fired power plant-based CO2 emissions to fuel conversion can counter GHG emissions while also mitigating fuel shortage. CO2 to methanol conversion pathway via the tri-reforming (TR) process is a useful valorization strategy which can achieve the aforementioned goals. The TR process primarily utilizes steam reforming of methane (SRM), dry reforming of methane (DRM) and partial oxidation of methane (POX) to convert waste CO2 to syngas using co-reactants such as methane, oxygen and steam and this syngas can be converted to methanol. In this paper, the water electrolysis (WE) integrated tri-reforming coupled methanol production (TRMP) process has been advanced via novel process modifications and optimized. In this process, O2 and H2 from the WE unit are supplied to the tri- reforming (TR) and methanol production (MP) units respectively. The following process modifications were implemented: (a) throughput of the WE unit is increased and excess oxygen is routed to support the combustion of the purge stream (b) CO2 flow from the combusted purge stream is sent to the TR reactor as recycle, and (c) the excess electrolyzer hydrogen counters the excess CO2 load of the process due to recycling. Process optimization has been executed using Component object model (COM) interface aided Aspen Plus-Python integration leading to implementation of the differential evolution algorithm. Results clearly demonstrated that the implemented process modifications worked synergistically to bring significant improvements in process metrics, namely, the CO2 valorization and profit generating potential of the process.