CO₂ Capture from IGCC by Low-Temperature Synthesis Gas Separation

Abstract

Capture conditions for CO2 vary substantially between industrial point sources. Depending on CO2 fraction and pressure level, different capture technologies will be required for cost- and energy-efficient decarbonisation. For decarbonisation of shifted synthesis gas from coal gasification, several studies have identified low-temperature CO2 capture by condensation and phase separation as an energy- and cost-efficient option. In the present work, a process design is proposed for low-temperature CO2 capture from an Integrated Gasification Combined Cycle (IGCC) power plant. Steady-state simulations were carried out and the performance of the overall process, as well as major process components, were investigated. For the baseline capture unit layout, delivering high-pressure CO2 at 150 bar, the net specific power requirement was estimated to 273 kJe/kgCO2, and an 85% CO2 capture ratio was obtained. The impact of 12 different process parameters was studied in a sensitivity analysis, the results of which show that compressor and expander efficiencies, as well as synthesis gas separation temperature, have the highest impact on power requirements. Modifying the process to producing cold liquid CO2 for ship transport resulted in 16% increase in net power requirements and is well suited for capturing CO2 for ship transport.

Keywords

• CCS
• CO₂ capture
• IGCC
• precombustion
• low-temperature
• cryogenic