GB1244891A - Improvements in or relating to vapor generators - Google Patents

Abstract

1,244,891. Vapour generators. E. S. MILIARAS. 23 June, 1969 [28 June, 1968], No. 31622/69. Heading F4A. A fossil fuel fired vapour generating system comprises a furnace section 6, a super-heating section 10a, and an economizer section 12, with a flue gas flow path 7 passing through the sections, and a secondary device 13 which can supply supplementary hot gases to increase the heat input to the feedwater at the economizer and so increase the vapour energy output of the system. At peak demand times additional fuel is introduced through a burner 14 and burned in a chamber 13, combustion air being provided by a fan 15. A damper 17 is closed when the increased vapour generator output feature is not required. Alternatively the additional combustion may take place in the space directly upstream of the economizer in the flow gas path 7, the fuel being introduced through a burner 16. The invention is shown in use with a highpressure turbine 30, a low-pressure turbine 31 driving an electrical generator 32, a condenser 34, closed feedwater heaters 35 supplied with steam through valves 37, a deaerating heater 36 and a demand sensor 38. When this sensor detects an increase in electrical demand it sends signals to close valves 37 thus increasing steam flow through the turbines, opens damper 17, operates fan 15 and fires additional fuel in burner 14 thus increasing heat input to the economizer and so allows increased electrical output for short periods to meet peak demand. In another embodiment, Fig. 2 (not shown), the secondary device has a second supplementary duct (21) downstream of the economizer to permit recirculation of the combustion gases. In a further embodiment, Fig. 3 (not shown), a second supplementary duct (25) is located downstream of the economizer and a third supplementary duct (25a) on the furnace 6 side of the system.