GB1242359A - Heat exchanger of the shell and the tube type - Google Patents

Abstract

1,242,359. Tubular heat exchangers; Incinerators. DORR-OLIVER Inc. 5 Feb., 1970, No. 5537/70. Headings F4B and F4S. A heat exchange unit 10 for preheating combustion air to be supplied as underblast to a fluidized bed type refuse incinerator 11 comprises an L-shaped tube bundle 34 of loop tubes connected to a tube plate T and contained within a easing having an inlet 47 and outlet 48 for hot combustion gases supplied from the incinerator 11. Air to be preheated is supplied to the lower chamber 61 of header 59 by a blower 12, is heated on passing through the loop tubes, and thereafter fed to the windbox 16 of the incinerator from the upper header chamber 62. Horizontal transverse support bars 65 are provided for securing the horizontal outlet portion of each loop tube against lateral deflection while allowing unrestricted thermal elongation. The tube bundle comprises a plurality of vertical assemblies of loop tubes 53, 54, 55, proper spacing of these assemblies being ensured by means of inverted U-shaped spacer elements (67, Fig. 8). The casing corner section bounded by flanges 35, 36 is removable for inspection and cleaning purposes. Soot blowers 68a in the form of transversely extending blower tubes are provided for periodic cleaning of the tubes. The refuse incinerator 11 comprises a combustion chamber 15 separated from the windbox by a member 14. Material to be burnt, e.g. dewatered sewage sludge, is fed at 17 into the fluidized bed B of sand. A burner R provides hot fluidizing gas at start-up whereafter, when combustion in the bed is self-sustaining, preheated combustion air from the heat exchange unit 10 provides the bulk of the fluidizing gas. Supplementary fuel may be added if required.