Power-generation plant equipment and operating method for the same

Abstract

Power-generation plant equipment of the present invention is provided with a steam-flow-volume adjusting valve that is provided in a superheated-steam pipe on the upstream side of a steam turbine. During startup of the steam turbine, a controller of the power-generation plant equipment increases a degree of opening of the steam-flow-volume adjusting valve from a closed position, thus increasing the frequencies of the steam turbine and an exhaust-heat-recovery generator; and, after the frequency of the exhaust-heat-recovery generator reaches the frequency of a grid, the controller connects an exhaust-heat-recovery-side breaker to supply power to the grid, and also sets the degree of opening of the steam-flow-volume adjusting valve to a substantially fully-open position, thus, operating the steam turbine depending on the frequency of the grid.

1 . Power-generation plant equipment comprising:
 a diesel engine;   a main generator that generates power by means of a driving force gained from the diesel engine and that supplies the power to a grid;   a steam generating device that generates steam by recovering exhaust heat from exhaust gas expelled from the diesel engine;   a steam turbine that is driven by the steam generated at the steam generating device;   an induction-type exhaust-heat-recovery generator that generates power by means of a driving force gained from the steam turbine and that supplies the power to the grid;   an exhaust-heat-recovery-side breaker that is disposed in a power cable between the exhaust-heat-recovery generator and the grid;   a steam-flow-volume adjusting valve that is provided in a steam flow channel on the upstream side of the steam turbine; and   a controller that controls the exhaust-heat-recovery-side breaker and the steam-flow-volume adjusting valve,   wherein, during startup of the steam turbine, the controller increases a degree of opening of the steam-flow-volume adjusting valve from the closed position, thus increasing frequencies of the steam turbine and the exhaust-heat-recovery generator; and, after the frequency of the exhaust-heat-recovery generator reaches the grid frequency, the controller connects the exhaust-heat-recovery-side breaker to supply power to the grid, and also sets the degree of opening of the steam-flow-volume adjusting valve to a substantially fully-open position, thus, operating the steam turbine depending on the grid frequency.   
     
     
         2 . Power-generation plant equipment according to  claim 1 , further comprising:
 a pressure control valve provided on the upstream side of the steam-flow-volume adjusting valve,   wherein the controller closes the pressure control valve when the pressure in the steam flow channel drops to or below a predetermined value.   
     
     
         3 . Power-generation plant equipment according to  claim 1 , wherein, when the pressure in the steam flow channel reaches or exceeds the predetermined value, the controller switches the flow of the steam toward a condenser provided on the downstream side of the steam turbine, bypassing the steam turbine. 
     
     
         4 . A method of operating power-generation plant equipment, which is provided with
 a diesel engine;   a main generator that generates power by means of a driving force gained from the diesel engine and that supplies the power to a grid;   a steam generating device that generates steam by recovering exhaust heat from exhaust gas expelled from the diesel engine;   a steam turbine that is driven by the steam generated at the steam generating device;   an induction-type exhaust-heat-recovery generator that generates power by means of a driving force gained from the steam turbine and that supplies the power to the grid;   an exhaust-heat-recovery-side breaker that is disposed in a power cable between the exhaust-heat-recovery generator and the grid;   a steam-flow-volume adjusting valve that is provided in a steam flow channel on the upstream side of the steam turbine; and   a controller that controls the exhaust-heat-recovery-side breaker and the steam-flow-volume adjusting valve, wherein, during startup of the steam turbine, the controller increases a degree of opening of the steam-flow-volume adjusting valve from the closed position, thus increasing frequencies of the steam turbine and the exhaust-heat-recovery generator; and, after the frequency of the exhaust-heat-recovery generator reaches the grid frequency, the controller connects the exhaust-heat-recovery-side breaker to supply power to the grid, and also sets the degree of opening of the steam-flow-volume adjusting valve to a substantially fully-open position, thus, operating the steam turbine depending on the grid frequency.   
     
     
         5 . Power-generation system comprising:
 a diesel engine;   a main generator that supplies the power to a grid;   a steam generating device that generates steam by recovering exhaust heat from exhaust gas expelled from the diesel engine;   a steam turbine that is driven by the steam generated at the steam generating device;   an exhaust-heat-recovery generator that generates power by means of a driving force gained from the steam turbine and that supplies the power to the grid;   an exhaust-heat-recovery-side breaker that is disposed in a power cable between the exhaust-heat-recovery generator and the grid;   a steam-flow-volume adjusting valve that is provided in a steam flow channel on the upstream side of the steam turbine; and   a controller that controls the exhaust-heat-recovery-side breaker and the steam-flow-volume adjusting valve,   wherein, during startup of the steam turbine, the controller increases a degree of opening of the steam-flow-volume adjusting valve from the closed position, thus increasing frequencies of the steam turbine and the exhaust-heat-recovery generator; and, after the frequency of the exhaust-heat-recovery generator reaches the grid frequency, the controller connects the exhaust-heat-recovery-side breaker to supply power to the grid, and also sets the degree of opening of the steam-flow-volume adjusting valve to a substantially fully-open position, thus, operating the steam turbine depending on the grid frequency.   
     
     
         6 . Power-generation system according to  claim 5 , further comprising:
 a pressure control valve provided on the upstream side of the steam-flow-volume adjusting valve,   wherein the controller closes the pressure control valve when the pressure in the steam flow channel drops to or below a predetermined value.   
     
     
         7 . Power-generation system according to  claim 5 , wherein, when the pressure in the steam flow channel reaches or exceeds the predetermined value, the controller switches the flow of the steam toward a condenser provided on the downstream side of the steam turbine, bypassing the steam turbine. 
     
     
         8 . A method of power generation, comprising:
 generating steam by recovering exhaust heat from exhaust gas expelled from the diesel engine;   driving a steam turbine by the steam generated at the steam generating device;   driving an exhaust-heat-recovery generator by means of a driving force gained from the steam turbine to supply the power to the grid;   fully closing a steam-flow-volume adjusting valve that is provided in a steam flow channel on the upstream side of the steam turbine before startup of the steam turbine;   increasing a frequency of the exhaust-heat-recovery generator by increasing the degree of opening of the steam-flow-volume adjusting valve to accelerate a rotational speed of the steam turbine during startup of the steam turbine; and   operating the steam turbine depending on the frequency of the grid in such a way that a power output from the exhaust-heat-recovery generator is supplied to the grid and that the degree of opening of the steam-flow-volume adjusting valve is set to a substantially fully-open position after the frequency of the exhaust-heat-recovery generator reaches a frequency of the grid.