GB894533A - Steam generators having two combustion chamber systems - Google Patents

Abstract

894,533. Forced-flow steam generators; superheaters. SULZER FRERES S.A. March 3, 1959 [March 12, 1958], No. 7353/59. Classes 123(2) and 123(3) A forced-flow generator for operation at subcritical, critical or supercritical pressure has two combustion chamber systems I, II which accommodate vaporizers and preliminary superheaters 16, 17 and 39, 40 respectively, the upper ends of the combustion chambers of the two systems 1, II accommodating respectively a reheater 23 and both of the final superheaters 78, 41. The system II can be put into operation, with the system I idle, by almost closing a value 62 in a steam output line 42, leading from the final superheater 41 to a turbine 43, and opening a valve 66, in a by-pass line 63 connected to a feed water tank 11, until the required steam pressure and temperature is reached in the line 62, a small quantity of steam being fed through the partially open valve 62 to preheat the turbine 43. When the required values of steam temperature and pressure have been reached the valve 62 is fully opened and the valve 66 is closed to put the turbine into operation. A feed pump 13, or an auxiliary pump not shown, circulates a small amount of water through the tubes of the system I, with an associated tiltable burner 51 still out of operation, in order to cool the final superheater 18, the circulated water being returned to the tank 11 through a line 64 controlled by a valve 65, and a valve 61 in a steam output line 19 from the final superheater 18 being closed. In order to put the system II into operation the burner 51 is lit and the feed-water pump 13 is started, the values 61, 65 being opened and closed respectively after the required steam temperature and pressure has been achieved. To cool the reheater 23 during the starting of the combustion in system I steam from the system II is available which is independent of the state of operation of system I. The outgoing steam from the turbine 43 is fed through a line 27 to the reheater 23, having a by-pass 27 controlled by a valve 28, and then to a second turbine 25 or through a by-pass 128 controlled by a valve 127. A condensate pump 26 delivers condensate from a condenser 26 through a line 31, containing a feedwater preheater 32, back to the tank 11. The tiltable burners 51, 52 are controlled by servomotors 57, 58 responsive to temperature sensitive elements 79,87 located respectively in the output lines of the reheater 23 and the final superheater 41 of the system II. The temperature of the steam leaving the final superheater 18 of the system I is regulated by injecting water from a line 86, with a valve 85, into the steam at a point 82 between the preliminary and final superheaters 17, 18, the valve 85 being regulated by a temperature sensing element 83 in the steam output line 19. In this way the intermediate superheating temperature of the steam can be regulated by displacing the tiltable burner 51 without there being an adverse effect on the steam in the line 19. The fuel supplied through lines 53, 55 to the burners 51, 52 is controlled by valves 54, 56 which are regulated by motors under the influence of pressure sensitive elements 75, 77 located respectively in the steam output lines 19, 42. Feed water from the tank 11 is supplied by pumps 13, 36 through valves 14, 37 and economisers 15, 38 to the vaporizers 16, 39 of the two systems I, II the valves 14, 37 being controlled by motors influenced by temperature sensitive elements 71, 73 situated respectively at the input ends of the preliminary superheaters 17, 40.