Integration of a CaO-based energy and CO2 storage system in an IGCC plant with carbon capture

摘要

Integrated gasification combined cycle(IGCC)plants have significant potential for efficient power generation with carbon capture(CCS).The IGCC process with CCS,however,has multiple temperature and flow constraints which severely limit its flexibility to meet the dynamic demands of the current grid.An energy and CO2 storage system based on the reversible reaction of CaO with CO2 is therefore proposed herein,to enable a temporary increase in the IGCC peak power output.This is achieved by(1)providing additional high quality heat for electricity production and(2)providing temporary CO2-storage,reducing the parasitic load of the CCS system at peak power demand.In contrast to existing concepts,the carbonation-calcination loop herein is operated in a cyclic mode; the CaCO3 produced during carbonation is not regenerated immediately,but stored until off-peak periods during which the formed CaCO3 can be regenerated resulting in a concentrated CO2-stream ready for sequestration.Apart from the system itself,this article presents an approach to integrate the novel system in a reference IGCC plant with CCS.The integrated system is modeled in Aspen Plus combined with a 0D correlation for the calculation of the CO2-adsorption in the carbonator.The integration analysis presented demonstrates the various challenges associated with implementing a discontinuous system.The optimal integration of the proposed system with a reference IGCC plant is explored.The performance of the integrated IGCC plant is analyzed and compared with a conventional IGCC plant for similar operating conditions.The simulation results show that the storage system improves the ramp-up ability of the IGCC plant,allowing a significant increase in the plant's net peak power output.Beyond meeting grid demand,the system additionally offers the potential for increased revenues from electricity price arbitrage.