ES354995A1 - Shell and tube heat exchangers - Google Patents

Abstract

In a tubular heat exchanger in which a high temperature fluid (e.g. hot gas at 2300 F.) flows through tubes 14 from an inlet header 20 defined in part by a tube plate 16, impingement of the hot fluid stream directly on to the tube plate 16 is prevented by a fluid-cooled shield plate 22 positioned in front of the tube plate and so arranged that both sides of the shield plate are subjected to substantially identical pressures. Hence the shield plate can be of relatively thin material and in an apparatus in which the temperature and pressure differences in the heat exchanging fluids are high, the stresses in the tube plate material are reduced. As shown, the shield plate 22 is hollow and cooling fluid is conveyed to and from the plate by way of conduits 34 (only one being shown). The shield plate is spaced from the tube plate 16 and this space 32 may be empty or the plate 16 can be provided with a thin layer ofinsulating or refractory material. Stub tubes 30 extend through the shield plate to convey the hot gas into the heat exchange tubes 14. The peripheral wall of the header is defined by the casing 10 of the heat exchanger and is lined with a refractory material 42 shaped to locate the shield plate. Alternatively the shield plate may be attached to the inner periphery of the shell 10 by a flexible sealing device. The shield plate cooling fluid may be water which is vaporized in the shield plate to provide a useful auxiliary supply of steam. In the event that the external fluid 18 is water some of this may be utilized as the shield plate cooling fluid.