GB1375377A - - Google Patents

Abstract

1375377 Vapour heaters BABCOCK & WILCOX Ltd 25 Nov 1971 [25 Nov 1970] 54897/71 Heading F4A A vapour heating unit includes means defining a gas flow path, first and second sets of vapour flow paths A, E, of which each contains a tube bank, the tube banks being disposed so that each of the tube banks of the first set A is aligned in the direction of gas flow with a tube bank of the second set E, and a heat exchanger B downstream of the tube banks in each flowpath of the first and second sets, the tube bank 19 that is included in one of the vapour flow paths in which the heat exchanger 18 is included is not aligned with the tube bank 17 that is included in the other of the vapour flow paths in which this heat exchanger 18 is included. The gas pass 1 is sub-divided into four vertical heating zones 6, 7, 8, 9 and has tubular walls forming a four-circuit final evaporator. The combustion chamber 2 is provided with corner firing pulverized fuel burners 3. Intermediate pressure steam enters through pipe-lines 15 and travels through the reheating stage A, the heat exchangers B and then through reheating stages C and D. Saturated steam from separators 11 passes through superheating stage E, heat exchangers B and superheating stages F and G, the saturated steam circuits crossing in the zone H betweene the stage E and the heat exchangers B. Th invention is used to equalize the reheating and superheating across the gas pass 1 despite variations 4-of gas temperature.