Valorization of CO2/O2 streams from a novel reactor using oxy-fuel combustion

ICO2CH - Integrated CO2 Capture and Hydrogen production An integrated concept is being investigated for the low-cost capture from CO2 point sources with alkaline KOH-based media and renewable H2 production. The innovation is on the level of the water electrolyzer, which is fed by a CO2-rich, post-capture (bi)carbonate solution, that enables isolation of a 85:15 wt.% CO2/O2 gas mixture from the anolyte during operation . This eliminates the need for dedicated 'stripping' energy, since CO2 liberation is a consequence of OH-consumption during O2 production. Simultaneously, KOH is regenerated in the H2 evolution reaction, avoiding further capture utility costs. The high-purity CO2 stream can be valorized, in combination with H2 to produce e.g. synthetic fuels, next to O2 in (partial) oxy-fuel combustion, after a final CO2/O2 separation step.
This project will focus on the CO2/O2 valorization objective, namely:The valorization of O2 is experimentally investigated by a first identification of the operating limits of partial oxyfuel combustion in a NG fueled reciprocating engine, which will dictate feasible CO2 dilution and O2 enhancement levels for given CO2 emission reductions. Together with the measurements of incomplete combustion, correlated with theoretical predications of instability limits, the impact of O2/CO2 re-injection in partial oxy-NG combustion engine is determined.
One of the strengths of the ICO2CH project is the products of electrolyzer's anode gas stream of O2 and CO2 can be directly valorized in a decarbonized combustion process. By recirculating these products back to a combustor, partial oxy-fuel combustion with CO2 dilution is enabled, which can result in significant carbon abatement for heat and power generation. One of the great difficulties in standalone oxy-fuel combustion applications is the source of O2, which is typically provided by air separation units that are both energy intensive and expensive. With ICO2CH, the combustor and electrolyzer form an integral system, and ultimately as a whole a substantial portion of fugitive CO2 emissions can be avoided.