PLANT FOR COMBINED CYCLE POWER GENERATION USING WET FUEL, AND FUEL DRYING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a plant for combined cycle power generation using a wet fuel, the plant that solves problems of wet fuel drying and can improve wet fuel compatibility associated with moisture.SOLUTION: A dry gas supply system which guides bled dry gas to a coal pulverizer 50 includes: a high-temperature exhaust gas system in which a high-temperature exhaust gas pipe 60 bleeding high-temperature denitrated exhaust gas from a waste heat recovery boiler 40 is provided with a high-temperature gas flow rate regulating valve 63 and a high-temperature exhaust gas cutoff valve 65; and a low-temperature exhaust gas system in which a low-temperature exhaust gas pipe 61 bleeding low-temperature denitrated exhaust gas from a downstream outlet side of the waste heat recovery boiler 40 is provided with a low-temperature exhaust gas flow rate regulating valve 64 and a low-temperature exhaust gas cutoff valve 66. In addition to a normal operation mode in which a mixing rate of the high-temperature exhaust gas and low-temperature exhaust gas is adjusted to adjust the temperature of the dry gas, the dry gas supply system is provided with a drying capability increased operation mode in which the temperature of the high-temperature exhaust gas is raised by operating a steam turbine 90, operated with steam supplied from the waste heat recovery boiler 40, with its intake steam set pressure made higher than in the normal operation mode.