GB1083170A - Common startup system for vapour generators - Google Patents

Abstract

1,083,170. Raising steam in forced flow steam generators. COMBUSTION ENGINEERING Inc. Dec. 18, 1964 [Dec. 30, 1963], No. 51685/64. Heading F4A. A startup unit 70 for two steam generators No. 1 and No. 2 and which may also be used to start other generators in a steam generating plant operates as follows:- The generators comprise first heating sections 16, 26 with recirculating pump 18 and second superheating sections 30, 32, the two sections being separated by stop valves 72. Feedwater is supplied by pumps 10, 12 from the turbine condenser 48. During the initial phase of the startup of No. 1 generator valves 76, 78 of No. 2 are closed and the following numerals refer to No. 1 generator only. Valves 72, BTB and BT are closed and fluid passes from the first heating section via open valve 76, conduit 58 and valve BE to a separator 60, water being returned to the feedwater supply via valve WD and steam passes through valve SA, conduit 62, open valve 78 to the superheaters 30, 32, to initially load the turbine 38. Steam pressure control now transferred from the BE valve to the throttling valve BTB. The SA valve closes when the steam pressure in section 30 passed through BTB valve exceeds pressure in the separator. Turbine loading proceeds by increasing boiler output and with the turbine valves 36 set at a preselected minimum fixed opening the BTB valve is opened until the pressure drop becomes less than the critical valve, the BT valve is then gradually opened- When the boiler throttling valves BTB, BT are fully open, loading proceeds by turbine valves 36 and valve 72 may be opened and valves 76, 78 closed. The startup unit may then be used to start No. 2 or another generator on the plant in the same manner.