Enabling Low-Cost CO₂ Capture via Heat Integration

Hollow fiber sorbents in rapid thermal swing mode, packed bed solid sorbents in thermal swing mode, hollow fiber membranes, monoethanolamine-based liquid amines, and chilled ammonia CO 2 sorption systems are compared on an energetic basis for CO 2 capture from coal-fired power plants. The systems are compared on an intrinsic heat and auxiliary basis both with and without plantwide heat integration efforts. Without heat integration, every technology considered was shown to be highly parasitic, consuming between 1.0 and 4.0 GJ/(ton of CO 2 captured) (effectively between 40 and 100% parasitic, depending on plant efficiencies). When heat integration strategies are considered, such as utilizing feedwater preheating heat flows (without disrupting plant operation) and utilizing heats generated during CO 2 compression, the overall parasitic nature of the technologies decreases dramatically. Namely, chilled ammonia and zeolite MFI-based fiber sorbents consume approximately 0.07 and 0.13 GJ/(ton of CO 2 captured), respectively. The overall energetic analysis strongly suggests that CO 2 capture systems must be highly integrated with the plant systems for successful widespread deployment as retrofits to large power plants.