US 6,205,762 B1Granted

Combined cycle power generating plant and method of supplying cooling steam for gas turbine in same

AssigneeMitsubishi Heavy Industries, Ltd.

InventorsKazuo Uematsu, Kazuharu Hirokawa, Hidetaka Mori, Hideaki Sugishita

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Abstract

A combined cycle power plant includes a combination of a gas turbine plant and steam turbine plant. The gas turbine cooling steam temperature is adjusted appropriately so that the gas turbine can be made of easily obtainable material. Steam supplied from the intermediate pressure evaporator is mixed into the cooling steam supply passage for supplying therethrough exhaust steam from the high pressure steam turbine into the gas turbine high temperature portion as cooling steam. Thus, cooling steam temperature is lowered without lowering of the entire efficiency, and material of less heat resistant ability becomes usable as material forming the gas turbine high temperature portion to be cooled. Thus, design and manufacture of the gas turbine may be satisfied by less expensive and easily obtainable material.

Claims21

Dependent claims

A combined cycle power plant comprising:

a gas turbine plant having a high temperature portion, said gas turbine plant including a gas turbine, an air compressor driven by said gas turbine, and a combustor for burning fuel and compressed air from said air compressor;
a waste heat recovery boiler for generating steam by using exhaust heat from said gas turbine plant as a heat source, said waste heat recovery boiler including a high pressure steam generating portion, an intermediate pressure steam generating portion, and a low pressure steam generating portion;
a steam turbine plant including a high pressure turbine communicating with said high pressure steam generating portion of said waste heat recovery boiler so as to receive high pressure steam from said high pressure steam generating portion, an intermediate pressure turbine communicating with said intermediate pressure steam generating portion of said waste heat recovery boiler so as to receive intermediate pressure steam from said intermediate pressure steam generating portion, and a low pressure turbine communicating with said low pressure steam generating portion of said waste heat recovery boiler so as to receive low pressure steam from said low pressure steam generating portion;
and
a cooling steam supply passage communicating with said gas turbine plant, with said waste heat recovery boiler, and with said steam turbine plant so as to supply cooling steam into said high temperature portion of said gas turbine plant, wherein said cooling steam supply passage is adapted to receive and mix an exhaust steam from said high pressure turbine, a portion of the intermediate pressure steam generated by said intermediate pressure steam generating portion, and a cooling water spray such that a temperature of the cooling steam is adjusted to a temperature appropriate for cooling said high temperature portion of said gas turbine plant.

2 more elements

A combined cycle power plant comprising:

a gas turbine plant having a high temperature portion, said gas turbine plant including a gas turbine, an air compressor driven by said gas turbine, and a combustor for burning fuel and compressed air from said air compressor;
a waste heat recovery boiler for generating steam by using exhaust heat from said gas turbine plant as a heat source, said waste heat recovery boiler including a high pressure steam generating portion, an intermediate pressure steam generating portion, and a low pressure steam generating portion;
a steam turbine plant including a high pressure turbine communicating with said high pressure steam generating portion of said waste heat recovery boiler so as to receive high pressure steam from said high pressure steam generating portion, an intermediate pressure turbine communicating with said intermediate pressure steam generating portion of said waste heat recovery boiler so as to receive intermediate pressure steam from said intermediate pressure steam generating portion, and a low pressure turbine communicating with said low pressure steam generating portion of said waste heat recovery boiler so as to receive low pressure steam from said low pressure steam generating portion;
a fuel passage for supplying fuel to said gas turbine plant;
a high pressure turbine exhaust cooling passage for cooling an exhaust steam from said high pressure turbine, said high pressure turbine exhaust cooling passage and said fuel passage being arranged such that the exhaust steam from said high pressure turbine is cooled by the fuel being supplied to said gas turbine plant;
and
a cooling steam supply passage communicating with said gas turbine plant so as to supply cooling steam into said high temperature portion of said gas turbine plant, wherein said cooling steam supply passage is adapted to receive the cooled exhaust steam from said high pressure turbine exhaust cooling passage.

4 more elements

A combined cycle power plant comprising:

a gas turbine plant having a high temperature portion, said gas turbine plant including a gas turbine, an air compressor driven by said gas turbine, and a combustor for burning fuel and compressed air from said air compressor;
a waste heat recovery boiler for generating steam by using exhaust heat from said gas turbine plant as a heat source, said waste heat recovery boiler including a high pressure steam generating portion, an intermediate pressure steam generating portion, and a low pressure steam generating portion;
a steam turbine plant including a high pressure turbine communicating with said high pressure steam generating portion of said waste heat recovery boiler so as to receive high pressure steam from said high pressure steam generating portion, an intermediate pressure turbine communicating with said intermediate pressure steam generating portion of said waste heat recovery boiler so as to receive intermediate pressure steam from said intermediate pressure steam generating portion, and a low pressure turbine communicating with said low pressure steam generating portion of said waste heat recovery boiler so as to receive low pressure steam from said low pressure steam generating portion;
a gas turbine cooling steam supply passage communicating with said gas turbine so as to supply gas turbine cooling steam into said gas turbine of said gas turbine plant, said gas turbine cooling steam supply passage communicating with said high pressure turbine so as to receive exhaust steam from said high pressure turbine;
a combustor cooling steam supply passage communicating with said combustor so as to supply combustor cooling steam into said combustor of said gas turbine plant, said combustor cooling steam supply passage communicating with said high pressure turbine so as to receive exhaust steam from said high pressure turbine;
and
a reheater for receiving and reheating the gas turbine cooling steam discharged from said gas turbine so as to generate reheated steam, said reheater being located such that the combustor cooling steam discharged from said combustor is fed into the reheated steam at an outlet of said reheater.

4 more elements

A combined cycle power plant comprising:

a gas turbine plant having a high temperature portion, said gas turbine plant including a gas turbine, an air compressor driven by said gas turbine, and a combustor for burning fuel and compressed air from said air compressor;
a waste heat recovery boiler for generating steam by using exhaust heat from said gas turbine plant as a heat source, said waste heat recovery boiler including a high pressure steam generating portion having a high pressure superheater, an intermediate pressure steam generating portion, and a low pressure steam generating portion;
and
a steam turbine plant including a high pressure turbine communicating with said high pressure steam generating portion of said waste heat recovery boiler so as to receive high pressure steam from said high pressure steam generating portion, an intermediate pressure turbine communicating with said intermediate pressure steam generating portion of said waste heat recovery boiler so as to receive intermediate pressure steam from said intermediate pressure steam generating portion, and a low pressure turbine communicating with said low pressure steam generating portion of said waste heat recovery boiler so as to receive low pressure steam from said low pressure steam generating portion;
a superheated steam supply passage for supplying superheated steam from said high pressure superheater of said waste heat recovery boiler to said high pressure turbine;
a cooling steam supply passage communicating with said gas turbine plant and said high pressure turbine so as to supply exhaust steam from said high pressure turbine into said high temperature portion of said g as turbine plant for cooling said high temperature portion;
and
a high pressure turbine by-pass passage communicating between said superheated steam supply passage and said cooling steam supply passage.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/202,452Filed 15 Dec 1998
Priority: JP 9-09728415 Apr 1997
Granted: 27 Mar 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

F02C 7/18
Characterised by cooling medium: the medium being gaseous, e.g. air
F01K 23/10
Combustion heat from one cycle heating the fluid in another cycle: with exhaust fluid of one cycle heating the fluid in another cycle
F01K 23/106
With exhaust fluid of one cycle heating the fluid in another cycle: with water evaporated or preheated at different pressures in exhaust boiler
F02C 6/18
Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use: using the…