Combined cycle steam and gas units with the clean-up of the flue gases from carbon dioxide

Abstract

Projects of the Combined Cycle Steam and Gas Units (Combined Cycle Power Plants - CCPP) reveal a high efficiency when being applicated to reduce the air pollution caused by ash, SO and NO emissions. It was proven out by operation. Used to reduce CO 2 emissions, these units allow the obtaining of even better results. (This application will be of great importance in future.) “Freezing out” and alkanolamyn CO 2 disposal methods require a 1.3 – 1.4 times increased proportional fuel consumption. CO 2 “freezing out” in the CCPP cycle with intermediate gas cooling to to = 170 K partially equilibrates the capacity decrease of GTUs at the expense of the increase of the steam turbines' capacity. In Russia, a considerable practical experience in this type of CO 2 is being extracted in crystals at experimental plants from flue gas behind the expansion turbine. Regenerating units cooling gas under pressure ( p = 0.4 MPa) to to = 173 K before the expansion turbine were elaborated and tested in the refrigeration industry. Given here are thermal diagrams, characteristics of demonstration gas turbine and steam-gas plants with CO 2 disposal, equipment scheme and general project parameters for long-range CCPP. The efficiency of these CCPP will be 20% higher than that of modern pulverized-fuel blocks without CO 2 disposal.