Analysis of the sorbent energy transfer system (SETS) for power generation and CO_2 capture

摘要

The sorbent energy transfer system (SETS) has the potential for providing a significant reduction in CO_2 emissions from gaseous fossil fuel-fired electric power plants with minimal loss in power generating efficiency. Energy transfer is accomplished in two steps so that CO_2 does not come in contact with combustion air, thereby avoiding a costly and energy intensive CO_2 separation step. In the first step, gaseous fuel is oxidized by reduction of an appropriate metal oxide sorbent. The gas product contains only CO_2 and H_2O so that pure, sequestration-ready CO_2 is obtained after removing H_2O by condensation. The reduced sorbent is then re-oxidized using excess air. Dual, circulating fluidized-bed or transport reactors provide continuous, steady state operation. Base case Aspen Plus simulations of the SETS process coupled to a natural gas combined cycle (NGCC) show that approximately 50 of the CO_2 can be captured with an energy penalty of only approximately 5. Base case maximum operating temperature of the two SETS reactors was limited to 900 ℃ to maintain the structural stability of the sorbent and adhere to operating temperature limits of particulate filters. Increased reactor temperatures would permit increased capture of CO_2 with minimal additional energy penalty.