Proposal of ultra-high-efficiency zero-emission power generation systems

Abstract

Solid oxide fuel cell (SOFC) and protonic ceramic fuel cell (PCFC) have strong features that enables high efficiency power generation and efficient CO2 capture. Applying these technologies to the fossil fuel and biomass power generation, we can realize ultra-high efficiency zero-emission power generation by capturing liquefied CO2 (LCO2) for easy transport and utilization (CCU) or storage(fossil fuel CCS and bio-energy CCS: BECCS). In this study, we propose LCO2 capture ultra-efficient power generation systems consist of multi-stage SOFC/PCFC, oxygen or hydrogen transport membrane, CO2 cooling and liquidizing units driven by exhaust heat and generated power by fuel cells. Net power generation efficiency is estimated through heat mass balance analysis. As the results for natural gas, proposed PCFC system is suitable and expected 64.7 %LHV net power generation efficiency with more than 99 vol% LCO2 capture. For biogas direct supply case, net power generation efficiency of proposed PCFC system is 57%LHV with 99 vol% capture of CO2 in the air. These results indicates that proposed systems have quite strong potential that enables ultra-high efficient CO2-free fossil fuel power generation with CCS and CO2-reduction biomass fuel power generation with BECCS.