| 摘要 |
An environmentally benign steam power cycle (10) facilitates separation and capture of carbon dioxide from its combustion products. In the steam power cycle an oxy-combustion superheater (12) superheats steam (13A) previously evaporated from feedwater (28) in a steam generator (20), the resulting superheated steam and combustion products being used to drive a steam turbine (16) for power generation (18). The feedwater (28) is evaporated, referably raised to at least its critical point, and preferably given some superheat, by regenerative heat exchange in the steam generator, which comprises a heat exchange network (20A, 20B), in which (i) sensible heat is transferred to the feedwater from the exhaust stream of the turbine and (ii) sensible and latent heat is transferred to the feedwater from a plurality of turbine bleed streams (P1, P2, P3), including a turbine bleed stream (P1) taken at about half the critical pressure of steam from just after the highest pressure stage (14,15) of the turbine, and (iii) sensible heat is transferred to the feedwater from condensates of the turbine bleed streams. The feedwater (28) for the steam generator is produced by (i) condensation of steam from the turbine bleed streams (P1, P2, P3) during transfer of their heat of condensation to the feedwater in a plurality of heat exchange stages, and (ii) condensation of steam from the turbine exhaust stream (E) after transfer of its sensible heat to the feedwater in a plurality of heat exchange stages. Carbon dioxide produced in the oxy-combustion process is easily captured (26, 36) when the steam from the turbine exhaust stream and the turbine bleed streams is condensed, thereby leaving most of the carbon dioxide behind as a gas to be extracted from the cycle. |
