Modeling a novel combined solid oxide electrolysis cell (SOEC) - Biomass gasification renewable methanol production system

Chemical energy storage in the form of hydrogen is playing an important role in the synthesis of alternative energy carriers such as Synthetic Natural Gas (SNG), Methanol and Dimethyl ether (DME) supplementing with a carbon source. The only renewable carbon source is biomass, which is a limited resource. However, the addition of hydrogen could potentially extend the existing biomass resources. This paper describes the modeling of a novel combined Solid Oxide Electrolysis Cell (SOEC) and oxygen blown biomass gasification system using Aspen Plus. One of the advantages of using such a combined system is the use of oxygen for gasification and reforming. The comparison of reforming technologies showed that an autothermal reformer (ATR) could be an advantage since oxygen is already available from the electrolysis stack and the ATR produced syngas has a higher CO/CO₂ ratio, which increases the methanol synthesis's reaction rate. ATR requires much less energy ∼13 MW for almost complete methane conversion compared to ∼35 MW for Steam Reforming (SR). The advantage of using inter-cooled compression upstream or downstream for such a combined process has been explained. A methanol thermal conversion efficiency of 72.08% can be achieved for gasification and SOEC combined system compared to 55.7% for an only gasifier system.