Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Hitoshi Ishimaru

Yoji Nagai

Toyohiko Masuda

Shozo Nakamura

Shinichi Hoizumi

Youichi Hattori

Satoshi Kusaka

Hideyuki Sato

Takeshi Ueno

Toshiki Kobayashi

An operating method of a combined plant that has several gas turbines and exhaust heat recovery boilers which generate steam by exhaust gas from the gas turbines wherein exhaust gas from each of the heat recovery boilers is passed through exhaust gas ducts and discharged from a common chimney. The method includes operating a combined plant having plural axes which may be suitably started or stopped and having means for discharging exhaust gas from three or more gas turbines through one common chimney. When the pressure at a joining part of an exit duct of an exhaust heat recovery boiler is a positive pressure or the atmospheric temperature is higher than a preset atmospheric temperature, gas turbines can be re-started or stopped without back-flow of exhaust gas of the gas turbine.

Method of operating combined plant

A drain recovery system for the condensate feedwater system of a nuclear power plant having condensate pumps for boosting the condensate from a condenser, and feedwater heaters for heating the condensate from the condensate pumps. The drain recovery system is provided with drain pumping-up recovery having a drain tank for storing a feedwater heater drain, and drain pumps connected to the drain tank for pumping up the drain therein to inject it into said condensate feedwater system at a predetermined portion thereof, and drain level control device having a conduit connected between a portion of the drain pumping-up recovery system upstream of the drain pumps and a portion of the condensate feedwater system upstream of the condensate pumps for causing the drain in the drain tank to be returned to the portion upstream of the condensate pumps by a pressure differential therebetween so as to maintain a drain level in the drain tank at a predetermined position when the plant operates at a low load level or the drain pumps malfunction.

Drain recovery system for condensate feedwater system of nuclear power

A condensation system for use in a power plant including a steam generator and steam turbine comprises at least one side stream condenser. The side stream condenser defines therein first and second hot wells with the first hot well receiving therein condensate produced by condensing steam exhausted from the steam turbine. A condensate pump device forcibly delivers the condensate through a condensate feed line having one end thereof connected to the first hot well and the other end communicating with the second hot well. A first purification device is provided in the condensate feed line to remove impurities from the condensate flowing therethrough. A main condensate pump device forcibly delivers the condensate through a main condensate feed line having one end thereof communicating with the condensate feed line and the other end connected to the steam generator. A second purification device is provided in the main condensate feed line downstream of the main condensate pump device, for removing impurities from the condensate introduced into the steam generator through the main condensate feed line.

Condensation system for power plant

Condensation system for use in a power plant. The condensate system includes side stream condenser defining therein first and second hot wells. Condensate is delivered from the first to second hot well through a condensate feed line. Condensate is introduced from the condensate feed line into a tank through a first spill-over line. Condensate is supplied from the second hot well to the power plant through a main condensate feed line. Condensate is introduced from the main condensate feed line into the tank through a second spill-over line. Actuator is operative in response to signal from a level detector detecting level of condensate in the first hot well, to regulate opening degree of a supplementary feed valve in the supplementary feed line, to close one of first and second spill-over valves in the first and second spill-over lines, respectively, and to open the other spill-over valve.

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Hitachi, Japan

Hitoshi Ishimaru