Modeling and simulation of an integrated power-to-methanol approach via high temperature electrolysis and partial oxy-combustion technology

Abstract

The Power to methanol (PtMeOH) approach based on water electrolysis and CO2 capture is studied. The novelties are the integration of solid oxide electrolysis, partial oxy-combustion capture technology and methanol synthesis process, and the development and validation with experimental data of a SOEC system model using Aspen Custom Modeler. Simultaneously, CO2 capture bench-scale unit and methanol synthesis process have been modeled and experimentally validated using Aspen Plus. These three systems have been thermally integrated in a final model to assess its high-performance operation. As a result, a clean, synthetic methanol is produced, which can be used as fuel or energy storage. In this lab-scale, a SOEC system of 1.2 kW and a synthetic flue gas of 7 l/min (40% CO2, 60% N2) are considered to obtain a methanol flow of 0.16 kg/h, with an overall efficiency of 29% for the integrated scenario. The SOEC system with an optimized BoP has the highest energy consumption, mainly due to water electrolysis, with 44% of total required energy. The novel power-to-methanol integrated in this work achieves around 20% reduction of the energy penalties estimated for the base case and makes use of oxygen from electrolysis for partial oxy-combustion and the water by-product of methanol synthesis in water electrolysis. The integrated model of the overall process is considered a useful tool for future works focused on further scale-up of the process.