Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Tsuguo Hashimoto

Haruo Urushidani

Norihisa Wada

Tadao Arakawa

Yoshiki Noguchi

Kiyoshi Takeuchi

Taiji Inui

Tetsuzo Kuribayashi

Takeshi Ueno

Hiroshi Tsunematsu

Akihiro Kawauchi

Keiichi Toyoda

Eiji Yanai

Takashi Asao

A system configuration and operating method for a single shaft combined cycle plant includes a gas turbine, an exhaust heat recovery boiler for generating steam using exhaust heat discharged from the gas turbine, and a steam turbine driven by steam generated from the exhaust heat recovery boiler. Rotors of the gas turbine and rotors of the steam turbine are coupled. The steam turbine includes a high pressure turbine being supplied with and driven by high pressure steam generated at a superheater of the exhaust heat recovery boiler and a reheating turbine supplied with and driven by steam that passes through the high pressure turbine and is reheated by a reheater of the exhaust heat recovery boiler. The gas turbine operates independently and a regulated amount of cooling steam is supplied to the steam turbine in order to prevent superheating due to windage loss of the steam turbine rotating in an unventilated state. A bypass path is provided in parallel with the exhaust heat recovery boiler as a path through which cooling steam flows in order to further raise the cooling effect, and each turbine and a condenser are made to communicate so as to make pressure within the turbines low.

Single shaft combined cycle plant and operating thereof

Single shaft combined cycle plant and method for operating the same

In a system configuration and operating method for a single shaft combined cycle plant comprising a gas turbine (,), an exhaust heat recovery boiler (,) for generating steam using exhaust heat discharged from the gas turbine; and a steam turbine (,) driven by steam generated from the exhaust heat recovery boiler (,), rotors of the gas turbine (,) and rotors of the steam turbine (,) being coupled, and the steam turbine comprising a high pressure turbine (,) being supplied with and driven by high pressure steam generated at a superheater of the exhaust heat recovery boiler (,) and a reheating turbine (,) supplied with and driven by steam that passes through the high pressure turbine (,) and is reheated by a reheater of the exhaust heat recovery boiler (,), the gas turbine (,) operates independently, a regulated amount of cooling steam is supplied to the steam turbine (,) in order to prevent superheating due to windage loss of the steam turbine (,) rotating in an unventilated state, a bypass path (,) is provided in parallel with the exhaust heat recovery boiler (,) as a path through which cooling steam flows in order to further raise the cooling effect, and each turbine and a condenser (,) are made to communicate so as to make pressure within the turbines low.

Single shaft combined cycle plant and operating method thereof

A power generation plant comprising a gas turbine and a waste heat recovery boiler in which feed water is heat-exchanged with exhaust gas from the gas turbine to produce vapor. A steam turbine system incorporates a reheat turbine and a high pressure turbine to which the vapor is supplied from the waste heat recovery boiler, with a generator being driven by the steam turbine system and condenser for condensing vapor from the stream turbine system into condensate and for supplying the condensate to the waste heat recovery boiler as the feed water. The waste heat recovery boiler is provided with a secondary reheater, a super heater, a primary reheater reheating vapor to be supplied to the secondary reheater and an evaporator for evaporating the feed water from the condenser into vapor and for supplying the vapor to the super heater, in order with respect to the exhaust gas flow. The vapor produced in the super heater is introduced into the high pressure turbine and the vapor produced in the secondary reheater is introduced into the reheat turbine.

Reheat type waste heat recovery boiler and power generation plant

In order to recover the heat of the waste gas from a gas turbine, a waste heat recovery boiler is provided, which has a high-pressure steam generating portion consisting of an economizer, a high-pressure steam generator and a superheater, and a low-pressure steam generating portion consisting of an economizer, and a low-pressure steam generator. The steam from the high-pressure generating portion is supplied to the turbine through a high-pressure steam pipe, and the steam from the low-pressure steam generating portion to the same through a low-pressure steam pipe. The high-pressure gland sealing steam is supplied to a high-pressure side steam gland portion the steam turbine through a high-pressure steam extracton pipe branching from the high-pressure steam pipe, a steam pressure regulator adapted to regulate the steam pressure and introduce the excess steam to a condenser, and a high-pressure gland sealing steam pipe. The low-pressure gland sealing steam is supplied to a low-pressure side steam gland portion through a low-pressure steam extraction pipe branching from the low-pressure steam pipe, a reducing valve adapted to supply steam of a constant pressure due to a depressurization operation, and a low-pressure gland sealing steam pipe.

Gland sealing steam supply system for steam turbines

A thermal power plant includes a main system in which steam generated in a boiler passes, through a steam regulating valve, a high pressure turbine, a reheater and an intercept valve, into an intermediate pressure turbine and a low pressure turbine. The thermal power plant further has a high pressure bypass system bypassing the steam regulating valve and the high pressure turbine, and an intermediate and low pressure bypass system bypassing the intercept valve and the intermediate and the low pressure tubines. Upon starting the thermal power plant, the steam generated in the boiler is delivered, through the high pressure bypass system, the reheater and the intercept valve, into the intermediate and the low pressure turbines to accelerate the turbines, and after a sinchronous steam supply, the steam is delivered into the high pressure turbine through the steam regulating valve to increase a load imposed on the power plant instead of being delivered into the high pressure bypass system. The method for starting the thermal power plant is characterized in that an opening control of the steam regulating valve is conducted when a reheated steam pressure becomes equal to or lower than a predetermined pressure level as a result of opening of the intercept valve.

Method for starting thermal power plant

An apparatus for controlling an operation of a turbine plant on a reduction of the load on a turbine operates to compute a saturation pressure corresponding to the temperature in the downcomer pipe by using the detected values representing the conditions of the plant, and to control the reduction of the turbine to maintain the pressure in the downcomer pipe higher than the computed saturation pressure so as to prevent an occurrence of flashing.

Method and apparatus for controlling an operation of plant

In shutting down a combined power plant, a steam turbine is first shutdown while operation of a gas turbine at high load is being continued, and the steam generated in a waste heat recovery boiler is passed on to a condenser through a bypass system bypassing the steam turbine. The gas turbine is then shutdown when this condition prevails, and gland sections of the steam turbine receive a supply of gland sealing steam which has been heated by a heater to a temperature level close to that of the steam attained while the steam turbine is in operation, thereby to maintain the temperature of the metal of the steam turbine gland sections at a desired level during the time the steam and gas turbines are shutdown. In restarting the combined plant, the gas turbine is first started and then the steam turbine is started.

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Hitachi, Japan

Tsuguo Hashimoto