A steam turbine of an opposed-current single-casing type has a high pressure turbine part and an intermediate-pressure turbine part housed in a single casing. A dummy ring partitions the high-pressure turbine part and the intermediate-pressure part, and a cooling steam supply path and a cooling steam discharge path are formed in the dummy ring in the radial direction. Extraction steam or discharge steam of the high-pressure turbine part, whose temperature is not less than that of the steam having passed through a first-stage stator blade, is supplied to the cooling steam supply path. The cooling steam is fed throughout the clearance to improve the cooling effect of the dummy ring and a turbine rotor. The cooling steam is then discharged through a cooling steam discharge path to a discharge steam pipe which supplies the steam to a subsequent steam turbine.

A steam turbine having a low-pressure inner housing NDIG and a high-pressure inner housing HDIG within a steam turbine outer housing, a reheater downstream of the HDIG and upstream of the NDIG wherein the first steam inlet section of the HDIG faces the second steam inlet section of the NDIG, a process steam deflection section for deflecting process steam out of the first steam outlet section into a gap between an inner wall of the steam turbine outer housing and an outer wall of the HDIG and of the NDIG, a high-pressure sealing shell for sealing the upstream end-section of the HDIG, a low-pressure sealing shell for sealing the upstream end-section of the NDIG, the high-pressure sealing shell located adjacent to the low-pressure sealing shell, wherein process steam can be drawn from the HDIG and conveyed to a region between the high- and low-pressure sealing shells.

A coal-fired power generation system and a supercritical CO.sub.2 cycle system thereof are provided. The supercritical CO.sub.2 cycle system includes a compressor unit and a turbine unit. The turbine unit includes a preceding stage heater, a preceding stage turbine, a last stage heater and a last stage turbine successively connected in series. An exhaust port of at least one of compressors in the compressor unit is in communication with the turbine unit through a split flow pipe, and a communication position between the split flow pipe and the turbine unit is located downstream of a suction port of the preceding stage turbine. An auxiliary regenerator and an auxiliary heater are provided at the split flow pipe, and the auxiliary regenerator is located upstream of the auxiliary heater.

A coal-fired power generation system and a supercritical CO.sub.2 cycle system thereof are provided. The supercritical CO.sub.2 cycle system includes a compressor unit and a turbine unit. The turbine unit includes a preceding stage heater, a preceding stage turbine, a last stage heater and a last stage turbine successively connected in series. An exhaust port of at least one of compressors in the compressor unit is in communication with the turbine unit through a split flow pipe, and a communication position between the split flow pipe and the turbine unit is located downstream of a suction port of the preceding stage turbine. An auxiliary regenerator and an auxiliary heater are provided at the split flow pipe, and the auxiliary regenerator is located upstream of the auxiliary heater.

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 steam turbine plant and an operating method thereof, and a combined cycle plant and an operating method thereof, include: a turbine; steam supply lines that supply main steam to the turbine; a steam control valve and an intercept valve provided to the steam supply lines; and a first auxiliary steam supply line that supplies auxiliary steam to the turbine via the steam supply lines which are located farther downstream than the steam control valve and the intercept valve.

A steam turbine, having a steam turbine outer housing; a high-pressure inner housing having first process steam inlet and outlet sections for conducting process steam therethrough from the inlet to the outlet section in a first process steam expansion direction; a low-pressure inner housing having second process steam inlet and outlet sections for conducting process steam therethrough from the second process steam inlet section to the second process steam outlet section in a second process steam expansion direction; and an intermediate superheater, which is arranged downstream of the high-pressure inner housing and upstream of the low-pressure inner housing, wherein the high-pressure and low-pressure inner housings are arranged within the steam turbine outer housing and the high-pressure and the low-pressure inner housings are arranged in such a way that the first steam inlet section of the high-pressure inner housing faces the second steam inlet section of the low-pressure inner housing.

A steam turbine, having a steam turbine outer housing; a high-pressure inner housing having first process steam inlet and outlet sections for conducting process steam therethrough from the inlet to the outlet section in a first process steam expansion direction; a low-pressure inner housing having second process steam inlet and outlet sections for conducting process steam therethrough from the second process steam inlet section to the second process steam outlet section in a second process steam expansion direction; and an intermediate superheater, which is arranged downstream of the high-pressure inner housing and upstream of the low-pressure inner housing, wherein the high-pressure and low-pressure inner housings are arranged within the steam turbine outer housing and the high-pressure and the low-pressure inner housings are arranged in such a way that the first steam inlet section of the high-pressure inner housing faces the second steam inlet section of the low-pressure inner housing.

A chemical plant and operating method therefor; the chemical plant comprises a steam turbine having a shaft, a first pressure turbine stage and a second pressure turbine stage, each being arranged on the shaft and being connected in series in terms of the steam process; steam for driving the steam turbine is obtained from a reactor plant, said reactor plant producing a hydrogen-containing substance from a carbon-containing energy-carrier stream; the steam is heated in an overheating step before being supplied to the second pressure turbine stage; the steam turbine has a third pressure turbine stage which is arranged on the shaft and which is connected between the first pressure turbine stage and the second pressure turbine stage in terms of the steam process; and the steam passes through the overheating step after exiting the third pressure turbine stage.

A chemical plant and operating method therefor; the chemical plant comprises a steam turbine having a shaft, a first pressure turbine stage and a second pressure turbine stage, each being arranged on the shaft and being connected in series in terms of the steam process; steam for driving the steam turbine is obtained from a reactor plant, said reactor plant producing a hydrogen-containing substance from a carbon-containing energy-carrier stream; the steam is heated in an overheating step before being supplied to the second pressure turbine stage; the steam turbine has a third pressure turbine stage which is arranged on the shaft and which is connected between the first pressure turbine stage and the second pressure turbine stage in terms of the steam process; and the steam passes through the overheating step after exiting the third pressure turbine stage.