| 摘要 |
The exit port of a gas air preheater (4) for exchanging heat between recirculating exhaust gas (34, 38) and exhaust gas (2) from a boiler body (1) for combusting oxygen is provided with a combined heat exchanger (5) containing: an exhaust-gas cooler transfer unit (16) to which a cooling fluid (15) is supplied from a supply pump (13); and an upstream-side GGH transfer unit (20) into which a circulating fluid (19) circulates when a circulation pump (17) causes the same to circulate between a downstream-side GGH (9) and the upstream-side GGH transfer unit (20). The exit port of the combined heat exchanger (5) has a low-low temperature EP (6) positioned therein. A heat-exchange-amount adjustment device (21) is further provided for adjusting the amount of heat exchanged between the exhaust-gas cooler transfer unit (16) of the combined heat exchanger (5) and the upstream-side GGH transfer unit (20) of the combined heat exchanger (5), and at least keeping the temperature of the exhaust gas in the entrance port of the low-low temperature EP (6) at an entrance-port-set temperature (T1). DRAWING FIG. 1 AA Ash |
