Synergistic methanol and DME production via thermochemical hydrogen and calcium looping CO2 capture in decentralised biogas-fuelled power plants

Abstract

This research examines a cohesive system that integrates Solid Oxide Fuel Cells (SOFC) fuelled by biogas, a Calcium Looping (CaL) CO₂ collecting mechanism, and a thermochemical hydrogen generation unit. The system is designed to create energy, sequester CO₂, and synthesise methanol and Dimethyl Ether (DME) as useful byproducts. We examine the efficiency, CO₂ collection capability, and economic feasibility of this decentralised biogas power plant using a thermodynamic and techno-economic study. Our results demonstrate that the SOFC system attains a net electrical efficiency of 56.6 % in independent operation. Nevertheless, the incorporation of the CaL and hydrogen production units diminishes this efficiency to 20.9 %, indicative of the energy requirements for CO₂ collection and fuel generation operations. The CaL system exhibited CO2 collection efficiencies ranging from 76 % to 99 %, correlating with enhanced synthesis of methanol and DME at elevated capture rates. At a CO₂ capture efficiency of 99 %, the system generates 1273.4 kg of methanol and 458.4 kg of DME for each megawatt-hour of energy produced. The techno-economic research indicated that capital expenditure is primarily influenced by the SOFC system (43 %) and CaL unit (30 %), whilst methanol and DME production represent 9 % and 13 % of the investment, respectively. Operational expenditure is mostly influenced by fuel and raw material expenses, accounting for 48 % of the total. This integrated system exhibits the capacity to markedly decrease CO₂ emissions while generating renewable fuels, presenting a feasible alternative for decentralised, sustainable energy production.