GB774225A - Steam turbine power plants with intermediate reheating between turbines - Google Patents

Abstract

774,225. Steam turbine plant. SULZER FRERES SOC. ANON. Dec. 21, 1954 [Dec. 23, 1953], No. 36863/54. Class 110 (3). [Also in Group XIII] A steam turbine power plant having a directly-heated intermediate reheater and an indirectly-heated regulatable intermediate reheater connected in series between two turbines has the side to which heat is supplied of the regulatable intermediate reheater connected between two superheaters of the steam generator and means for controlling the temperature of the reheated steam. Condensate from a condenser 1 is supplied by a pump 2 to a feed water tank 4 from which it is supplied by a feed pump 5 to a flue gas heated economizer 7, the vaporizing zone 8 of a steam generator and then through a pipe 9 into a first superheater 10. From the superheater 10 the steam flows through the primary side of an indirectly-heated regulatable intermediate reheater 12 into a second superheater 14 which is connected to a high-pressure turbine 16. The exhaust of the turbine 16 passes through the secondary side of the reheater 12 into a directly-heated intermediate reheater 18 and the low-pressure turbine 20. The heating effected in the reheater 12 can be controlled by taking water from the pipe 6 through a pipe 23 and injecting it into the pipe 9. The quantity of water injected is controlled by a valve 24 regulated by a device 25 influenced by temperature-sensitive elements 26 and 27 located in the pipes 9 and 19 respectively. The element 27 responsive to the reheated steam temperature forms the main control and the element 26 acts as a stabilizing control. A further temperature control, e.g. a second water injector pipe for injecting water into the pipe 13 may be provided to control the temperature of the steam entering the high-pressure turbine 16. The reheater 12 is preferably made of a low alloy ferritic steel and of welded construction. The reheater 18 may be made of austenitic steel and is preferably located in the steam generator where it is screened from flame radiation. In a modification, the reheated steam temperature is used to control a valve in a by-pass pipe in the primary or secondary sides of the reheater 12. The temperature-sensitive element 27 may be placed between the reheaters 12, 18. The turbine may consist of more than two turbines with more than one reheating stage, at least one of which comprises directly and indirectly heated reheaters arranged in series as described. The steam generator may be of any type and the invention is not restricted to the straight-through type shown.