The invention relates to a steam Rankine cycle plant and a method for operating thereof. The plant comprises a higher-pressure steam turbine with an outlet and a reheater fluidly connected to the higher-pressure steam turbine. In addition, the plant has a lower-pressure steam turbine with an inlet that is fluidly connected to the reheater. The plant also has a bypass that is fluidly connecting the outlet and the inlet so as to bypass the reheater.

Systems and methods axe disclosed herein that generally involve a double pinch criterion for optimization of regenerative Rankine cycles. In some embodiments, operating variables such as bleed extraction pressure and bleed flow rate are selected such that a double pinch is obtained in a feedwater heater, thereby improving the efficiency of the Rankine cycle. In particular, a first pinch point is obtained at the onset of condensation of the bleed and a second pinch point is obtained at the exit of the bleed from the feedwater heater. The minimal approach temperature at the first pinch point can be approximately equal to the minimal approach temperature at the second pinch point. Systems that employ regenerative Rankine cycles, methods of operating such systems, and methods of optimizing the operation of such systems are disclosed herein in connection with the double pinch criterion.

A system for reheating a power generation system including a boiler having a waterwall and a steam drum with an input fluidly coupled to the waterwall and an auxiliary heat source to provide heated fluid. The system also includes a first flow control valve connected to the auxiliary heat source and the boiler to control a flow of heated fluid from the auxiliary heat source to the waterwall; a first isolation valve disposed at a waterwall, to isolate circulation of heated fluid from the steam drum to the waterwall; and a sensor to monitor at least one operating characteristic in the boiler. The system also includes a controller to control at least one of the flow control valve, the isolation valve, and the auxiliary heat source to control the amount of heated fluid supplied to the waterwall when the boiler is not generating steam.

A system for reheating a power generation system including a boiler having a waterwall and a steam drum with an input fluidly coupled to the waterwall and an auxiliary heat source to provide heated fluid. The system also includes a first flow control valve connected to the auxiliary heat source and the boiler to control a flow of heated fluid from the auxiliary heat source to the waterwall; a first isolation valve disposed at a waterwall, to isolate circulation of heated fluid from the steam drum to the waterwall; and a sensor to monitor at least one operating characteristic in the boiler. The system also includes a controller to control at least one of the flow control valve, the isolation valve, and the auxiliary heat source to control the amount of heated fluid supplied to the waterwall when the boiler is not generating steam.

A system for reheating a power generation system including a boiler having a waterwall and a steam drum with an input fluidly coupled to the waterwall and an auxiliary heat source to provide heated fluid. The system also includes a first flow control valve connected to the auxiliary heat source and the boiler to control a flow of heated fluid from the auxiliary heat source to the waterwall; a first isolation valve disposed at a waterwall, to isolate circulation of heated fluid from the steam drum to the waterwall; and a sensor to monitor at least one operating characteristic in the boiler. The system also includes a controller to control at least one of the flow control valve, the isolation valve, and the auxiliary heat source to control the amount of heated fluid supplied to the waterwall when the boiler is not generating steam.

In one embodiment, a plant control apparatus controls a power plant. The plant includes a gas turbine, a generator driven by the gas turbine, an exhaust heat recovering boiler to generate first steam by using heat of exhaust gas from the gas turbine, a first steam turbine driven by the first steam, a reheater provided in the boiler and configured to heat exhaust steam from the first steam turbine by the exhaust gas to generate reheat steam, and a second steam turbine driven by the reheat steam. The apparatus includes a first warming-up module to supply second steam from equipment different from the boiler to the first steam turbine to warm up this turbine, before this turbine is started. The apparatus further includes a second warming-up module to supply the second steam to the reheater to warm up the reheater, before the first steam turbine is started.

In one embodiment, a plant control apparatus controls a power plant. The plant includes a gas turbine, a generator driven by the gas turbine, an exhaust heat recovering boiler to generate first steam by using heat of exhaust gas from the gas turbine, a first steam turbine driven by the first steam, a reheater provided in the boiler and configured to heat exhaust steam from the first steam turbine by the exhaust gas to generate reheat steam, and a second steam turbine driven by the reheat steam. The apparatus includes a first warming-up module to supply second steam from equipment different from the boiler to the first steam turbine to warm up this turbine, before this turbine is started. The apparatus further includes a second warming-up module to supply the second steam to the reheater to warm up the reheater, before the first steam turbine is started.

A steam power plant includes a first steam power plant, a second steam power plant, and an inter-unit. The first steam power plant includes a boiler, a high-pressure turbine, a first reheat line, a first feed water heater, and a high-pressure extraction steam line. The second steam power plant includes a boiler, a high-pressure turbine, a first reheat line, a first feed water heater, and a high-pressure extraction steam line. The inter-unit connected extraction steam line connects the high-pressure extraction steam line of the first steam power plant with the high-pressure extraction steam line of the second steam power plant.

A steam power plant includes a first steam power plant, a second steam power plant, and an inter-unit. The first steam power plant includes a boiler, a high-pressure turbine, a first reheat line, a first feed water heater, and a high-pressure extraction steam line. The second steam power plant includes a boiler, a high-pressure turbine, a first reheat line, a first feed water heater, and a high-pressure extraction steam line. The inter-unit connected extraction steam line connects the high-pressure extraction steam line of the first steam power plant with the high-pressure extraction steam line of the second steam power plant.

A power transmission apparatus for transmitting power generated by a power generation apparatus to a generator and a power generation system including the same are provided. The power transmission apparatus for transmitting power generated by the power generation apparatus to the generator may include a first disk part connected to one of the power generation apparatus and the generator, a second disk part connected to the other one of the power generation apparatus and the generator and disposed on a rear side of the first disk part, and a connection part configured to connect the first disk part and the second disk part and include a portion that decreases and then increases in diameter along a longitudinal direction.