RESUMO
A hybrid system combining amine scrubbing with membrane technology for carbon capture from natural gas combined cycle (NGCC) power plants is proposed in this paper. In this process, the CO2 in the flue gas can be enriched from 4% to 18% by the membrane, and the amine scrubbing system will have lower capture costs. Aqueous piperazine (PZ) is chosen as the solvent. Different direct contact cooler (DCC) options, multiple absorber operating conditions, optimal intercooling designs, and different cooling options have been evaluated across a wide range of inlet CO2. Amine scrubbing without DCC is a superior design for NGCC carbon capture. Pump-around cooling at the bottom of the absorber can effectively manage the temperature of the hot flue gas, and still be effective for CO2 absorption. The absorber gas inlet must be designed to avoid excessive localized temperature and solvent evaporation. When the inlet CO2 increases from 4% to 18%, total absorber CAPEX decreases by 60%; another 10% of the total absorber CAPEX can be saved by eliminating the DCC. In-and-out intercooling works well for high CO2, while pump-around intercooling is more effective for low CO2. Dry cooling requires more packing and energy but appears to be technically and economically feasible if cooling water availability is limited.
RESUMO
The Electric Power Research Institute (EPRI) undertook a multiyear effort to understand the landscape of postcombustion CO2 capture technologies globally. In this paper we discuss several central issues facing CO2 capture involving scale, energy, and overall status of development. We argue that the scale of CO2 emissions is sufficiently large to place inherent limits on the types of capture processes that could be deployed broadly. We also discuss the minimum energy usage in terms of a parasitic load on a power plant. Finally, we present summary findings of the landscape of capture technologies using an index of technology readiness levels.
