GB1239302A - - Google Patents

Abstract

1,239,302. Heating liquids. COAL INDUSTRY (PATENTS) Ltd. 6 May, 1969 [9 May, 1968, No. 22067/68. Heading F4A. In a method of heating a liquid by heat exchange with a fluidized bed of inert particles and finely divided fuel which is undergoing combustion, the bed is maintained in the fluidized state by an upward flow of gas through the bed, and the liquid is contained in a space surrounding the bed and is caused to flow therethrough. The bed of particles, e.g. crushed firebrick, is contained in a furnace chamber 4, supported by a mount 5, into which fluidizing air is passed via inlet conduit 16 and windbox 15 and through a perforated plate 11 supported on a hollow cylindrical member 12. Powdered coal is supplied pneumatically via inlet 17 and an open-ended T-piece 18 to be ignited by pilot burners. The level of the fluidized bed is kept constant by an overflow conduit 19. The water to be heated is contained in a jacket surrounding the chamber 4 and passes by convection or pumped circulation through tubes 20, arranged in staggered vertical rows, inclined at 5-20 degrees. Steam is produced and is discharged through an outlet 22 and water is supplied through a perforated inlet tube 25. Helical tubes 21 for the exhaust gases from the chamber 4 pass round the chamber and through an aperture 26 formed in the mount 5, the tubes supplying additional heat to the water and also to the incoming air in conduit 16. In a modification, Figs. 4-6 (not shown), the furnace chamber is partitioned by an apertured plate (36) and the smoke tubes are arranged vertically in series (38), (40), (41), the exhaust gases passing from the top part of the furnace chamber through the tubes (38), (40) and (41) in turn. In a further modification, Figs. 7, 8 (not shown), the tubes 20 are replaced by U-tubes (60) extending radially into the furnace chamber.