Investigations of an air-blown integrated gasification combined cycle fired with high-sulphur coal with post-combustion carbon capture by aqueous ammonia

•CO2 capture plants are proposed for an advanced IGCC fired with high-sulphur coal.•The desulphurization unit of the IGCC is strongly integrated with the CO2 capture plant.•Post-combustion CO2 capture by aqueous ammonia in chilled and cooled mode is investigated.•Overall IGCC performance is better in case of CO2 capture in cooled mode.•A specific primary energy consumption for CO2 avoided is calculated as low as 2.27MJ/kgCO2.

This work deals with CO2 capture plants for an advanced air-blown gasification-based combined cycle where a coal with high sulphur content, which is really relevant for the coal market, is used as feedstock. The sulphur removed as H2S from the coal-derived gas enters a wet sulphuric acid process. Later, the resulting acid is used to control ammonia slip in a post-combustion CO2 capture plant based on ammonia scrubbing and designed for a reduced energy demand. Thus, limiting the energy impact of the CO2 capture technology will improve the power plant efficiency, according to a presumable lower cost of the generated electricity, as a high-sulphur coal is used as fuel input.In detail, a cooled ammonia-based process is found to be more attractive than a more conventional chilled ammonia-based solution: in case of 90% of CO2 avoided, the overall power plant efficiency is equal to 41.7% and the SPECCA (specific primary energy consumption for CO2 avoided) as low as 2.3MJ/kgCO2. Moreover, the calculation results show the SPECCA for CO2 avoided ranging from 80% to 90% is almost constant, even though the power plant efficiency increases if lower levels of CO2 capture are considered.