GB794683A - Steam power plants employing forced-flow steam generators - Google Patents

Abstract

794,683. Steam-raising in boilers; feed water heating systems. SULZER FRERES SOC. ANON. May 22, 1956 [June 4, 1955], No. 15781/56. Class 64(1) and 123(2) [Also in Group XXVI] A steam power plant comprises a forced flow steam generator 1 including a superheater 9 and supplying at least two turbines 14, 20 connected in series, a reheater 16, a by-pass pipe 42 containing a valve 43 operated in dependence on the pressure at the outlet of the super-heater and a valve 45 which maintains the pressure in the pipe 42 constant at a value corresponding to the outlet pressure at full load of the turbine 14, a water separator 44, and a heating steam pipe 56 for a feed water preheater 32 which branches off from the pipe 42 between the separator 44 and the valve 45. The generator 1 may operate above or below critical pressure and includes an economizer 6, a main heating section 7 constituting the lining of the furnace 2, a superheater 9 and a reheater 16 connected between the two turbines. Steam from the turbine 22 passes into a condenser 23 and is then fed by a condensate pump 24 through preheaters 25 and 26 to a degasifier 28 connected by a feed pump 29, further preheaters 31, 32 and regulating valves 4, 5 to the generator 1. Steam is fed from the turbines to the preheaters through tapping pipes 33, 33<1>, 34 and 35 and non-return valves 36, 37 while the condensate is discharged through pipes 38...41 fitted with steam traps into the degasifier 28 and the condenser 23. Ten or more feed water preheaters may be used. During starting, the pipe 42 by-passes the turbine 14 and working medium from a , pipe 8 is fed through a control valve 47 to a separator 44 to cool the superheated steam .entering the separator 44 from the pipe 42 and to provide dry steam for cooling the reheater 16. A pipe 56 supplies steam to the preheater 32 while further pipes 57 and 59 provided with valves 58 and 60 arranged to open only when the pressure beyond them falls to a certain value supply steam to the preheater 31 and degasifier 28. Steam from the reheater 16 by-passes the turbine 20 through a pipe 51 fitted with a steam separator 53 connected by steam and water pipes 54, 55 to the condenser 23. The water from the separator 44 is discharged through a pipe 49 and a valve 50 controlled by the water level in that separator into the separator 53.