Patent ID: 9074480
Filing Date: 2015-07-07
Classification: F01D,F01K,F05D

Abstract:
1. A cooling method for a steam turbine generating facility having an opposed-flow single casing steam turbine which is arranged at a higher pressure side of a low pressure turbine, the opposed-flow single casing steam turbine having a plurality of turbine parts installed with respect to a shaft of a turbine rotor and housed in a single casing and a dummy seal which isolates the plurality of turbine parts from one another, the method comprising: supplying cooling steam generated in the steam turbine generating facility to a cooling steam supply path formed in the dummy seal, the cooling steam having a temperature lower than a temperature of working steam which has been supplied to each of the plurality of turbine parts of the opposed-flow single casing steam turbine and which has passed through a first-stage stator blade, and the cooling steam having a pressure which is not less than a pressure of the working steam which has passed through the first-stage stator blade; cooling the dummy seal and the shaft of the turbine rotor arranged on an inner side of the dummy seal by introducing the cooling steam, which reaches an outer surface of the shaft of the turbine rotor and branches off toward both sides of the shaft of the turbine rotor, to a clearance formed between the dummy seal and the shaft of the turbine rotor and streaming the cooling steam in the clearance against steam from an exit of the first-stage stator blade, with the branched cooling steam streaming toward turbine blades respectively provided at both sides of the shaft of the turbine rotor; and after the cooling the dummy seal and the shaft of the turbine rotor, discharging the cooling steam through a cooling steam discharge path formed in the dummy seal to a discharge steam pipe to supply steam to a subsequent steam turbine, wherein: the opposed-flow single casing steam turbine includes a high pressure side turbine part and a low-pressure side turbine part, and the working steam supplied to the high pressure side turbine part is different in pressure from the working steam supplied to the low-pressure side turbine part; the cooling steam discharge path is configured to open to the clearance at a position between the low-pressure side turbine part and the cooling steam supply path; the cooling steam reaching the clearance from the cooling steam supply path branches off into a first cooling steam flow streaming toward the low-pressure side turbine part and a second cooling steam flow streaming toward the high-pressure side turbine part; a part of the cooling steam of the first cooling steam flow is discharged through the cooling steam discharge path; the remnant of the cooling steam of the first cooling steam flow is supplied to a turbine blade cascade part of the low-pressure side turbine part; and the cooling steam of the second cooling steam flow is supplied to a turbine blade cascade part of the high-pressure side turbine part. after the cooling the dummy seal and the shaft of the turbine rotor, discharging the cooling steam through a cooling steam discharge path formed in the dummy seal to a discharge steam pipe to supply steam to a subsequent steam turbine, wherein: the opposed-flow single casing steam turbine includes a high pressure side turbine part and a low-pressure side turbine part, the working steam supplied to the high pressure side turbine part is different in pressure from the working steam supplied to the low-pressure side turbine part; the cooling steam supply path is configured to open to the clearance on a side of the cooling steam supply path nearer to the low-pressure side turbine part than the cooling steam discharge path; the cooling steam reaching the clearance from the cooling steam supply path branches into a third cooling steam flow that streams toward the low-pressure side turbine part and a fourth cooling steam flow streaming toward the high-pressure side turbine part; the cooling steam of the third cooling steam flow is supplied to a turbine blade cascade part of the low-pressure side turbine part through the clearance against the steam from the exit of the first-stage stator blade of the low-pressure side turbine part streaming from the low-pressure side turbine part into the clearance; and the cooling steam of the fourth cooling steam flow is discharged through the cooling steam discharge path along with the steam which branches from the exit of the first-stage stator blade of the high-pressure side turbine part.