Low-emission pre-combustion gas-to-wire via ionic-liquid [Bmim][NTf2] absorption with high-pressure stripping

Autothermal reforming is an important pathway to hydrogen via fossil fuel decarbonization. Traditionally, the finishing step of hydrogen production via autothermal reforming consists of decarbonation via conventional aqueous-amine absorption which incurs a huge energy penalty due to high heat-ratio and low-pressure carbon dioxide stripping entailing costly compression for geological storage. This work proposes and assesses an alternative high-pressure temperature-swing hydrogen decarbonation that promotes stripping at high-pressure reducing carbon dioxide compression costs. Such new hydrogen decarbonation uses 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide ionic-liquid physical-absorption due to its solute affinity, low vapor-pressure, high thermal stability and low heat consumption for carbon dioxide stripping at high-temperature and high-pressure. Technical and economic aspects of the ionic-liquid temperature-swing decarbonation are evaluated and compared with the conventional aqueous-amine decarbonation. Results showed that high-pressure ionic-liquid stripping requires 5.5 times less heat to produce a high-pressure carbon dioxide stream and reduces 4.3 times its compression power. These results directly impact net power exportation of the combined-cycle hydrogen-fired power plant; i.e., the ionic-liquid gas-to-wire exports 35.6% more electricity than the aqueous-amine counterpart. Economically, the ionic-liquid gas-to-wire has 36% higher revenues, entailing a net value 2.5 times higher (US$ 390.2*106) and 5 years lower payback-time than the conventional aqueous-amine counterpart. [Display omitted] •Gas-to-wire with pre-combustion capture via ionic-liquid absorption is assessed.•Pre-combustion capture via high-pressure temperature-swing ionic-liquid capture.•High-pressure ionic-liquid stripping entails lower cost carbon dioxide compression.•Best gas-to-wire power and net value from temperature-swing ionic-liquid capture.•Ionic-liquid gas-to-wire has 36% more revenues than the aqueous-amine counterpart.