GB762556A - Steam turbine plants - Google Patents

Abstract

762,556. Steam turbine plant. SULZER FRERES SOC. ANON. Oct. 29, 1954 [Oct. 31, 1953], No. 31279/54. Classes 110 (3) and 122 (3). [Also in Group XIII] A steam-turbine plant comprises a forced-flow boiler with two tube systems, connectable in parallel and heated independently by a first furnace 5 and a second furnace 7, supplying superheated steam to high, medium and lowpressure turbines 1, 2, 3. In operation, water is pumped from a condenser 9 by a feed pump 10 through a pipe 11 to an economiser section 12 and the flow is then divided on the one hand through a valve 14 to a steam-generating section 15 in the first furnace 5 and on the other hand through a valve 18 to a steam-generating section 19 in the second furnace 7. From the steam-generating section 15, the steam passes through a superheater 16 and through a valve 21 to a pipe 23 connected to the inlet of the high-pressure turbine 1. Steam generated in the section 19 is superheated in a section 20 and is also delivered to the high-pressure turbine 1 through pipe 23. Exhaust from the H.P. turbine 1 passes through a reheater 27 in the first furnace 5 and is then delivered through a pipe 28 to the medium-pressure turbine 2. Exhaust from this M.P. turbine 2 is fed through a pipe 30 to a reheater 31 in the second furnace 7 and is then delivered through a pipe 32 to the lowpressure turbine 3 which is exhausted to condenser 9. On starting the plant, the valve 13 is closed and the valve 18 adjusted so that only 15 to 40 per cent of the full load feed water passes through the water-tube section 19 and superheater section 20. Also the burner 8 in this section is adjusted so that the reheater section 31 is not overheated. With valve 22 closed and valve 34 opened the working medium is conducted to the condenser 9 via a water separator 35 and steam trap 36. When steam is produced it flows through pipes 38, 30 into reheater 31 from which the steam is fed through pipes 32, 40 to a second water separator 41 which exhausts water and steam to the condenser 9. A water injector 50 in the separator 41 is controlled by a device t and ensures that the steam is cooled sufficiently to condense in the condenser. As the reheater 31 is now cooled, the output of the burner 8 is increased to an extent corresponding to the amount of working medium flowing through. Some of the superheated steam generated is then passed through valve 22 and pipe 23 to the H.P. turbine 1 from which it passes to reheater 27 and then to the M.P. turbine 2. The exhaust from this turbine enters pipe 30 and meets steam flowing through pipe 38 from water separator 35. A water injector 46 in the separator 35 is controlled by a device t and maintains the temperature of steam in the pipe 38 the same as the steam temperature in pipe 30. On leaving reheater 31 some of the steam is now passed through the L.P. turbine 3 to the condenser 9. Since the reheater 27 is now cooled, 15 to 40 per cent of the maximum feed water is supplied to the steam-generating tubes 15 and superheater 16 in furnace 5 and 15 to 40 per cent of the maximum burner output applied. The working medium flows through a valve 45 to water separator 41 which exhausts water and steam to the condenser 9. When superheated steam leaves superheater 16 the two systems are connected in parallel. The generator 4 can then be connected to the electric network, whereupon the whole of the steam can be conducted to the turbines and the amount of feed water and burner output increased to suit the load. Specification 762,555 is referred to.