GB449050A - Temperature regulating apparatus - Google Patents

Abstract

<PICT:0449050/III/1> <PICT:0449050/III/2> <PICT:0449050/III/3> <PICT:0449050/III/4> <PICT:0449050/III/5> The temperature of a contact mass during endothermic or exothermic reactions is regulated by passing one or more streams of heating or cooling fluid through the mass, which is in the form of a deep and continuous bed, at such a speed that the change in temperature of the fluid is insufficient to cause any substantial difference in the rates of heat transfer along its path, and keeping the fluid out of heat conducting relation with the contact mass, so that heat - exchange is effected mainly by radiation. In the arrangement shown in Fig. 1, the contact mass M is disposed in a converter 7, and its temperature regulated by fluid passed through conduits 15 which are kept from direct contact with the catalyst by outer members 18. When a liquid medium, such as water, is used, the upper header 16 is provided with a pressure reducing valve 20 leading into flashpot 22, vapour being released by valve 22. The condensate is passed, via line 23 together with makeup, to pump 25 whence it is recycled to the converter. Fig. 1A shows an arrangement external to the converter for use with either a liquid or gaseous medium. The header 16 leads to pump 25a and thence to a device 21a functioning either as a heater or cooler, from which pump 25b returns the medium to the converter, makeup being added from line 24a. The device 21a may be bye-passed wholly or partly by a valved connection 22a. The reactants are introduced into and withdrawn from the converter by means of apertured conduits 27 and 28, preferably uniformly spaced. Alternatively the members 18 enclosing the conduits carrying the heat-exchange medium may be perforated and the reactants introduced or withdrawn therethrough, and in this case, heat-exchange is partly by convection through the gases passing between the contact mass and the heat-exchange medium. Figs. 3 and 4 show modifications in which the flow of the medium is reversed within the chamber, either by nested concentric pipes 29 and 30 in Fig. 3, or by means of a single pipe 32 bent into a loop as in Fig. 4. The outer enclosing members may be provided with fins to facilitate heat transfer, e.g. as shown in Fig. 6, in which long fins 35 are provided with transverse fins 36. Fins may also be provided on the conduits carrying the heat-exchange fluid, and the outer wall of the above conduit and the inner wall of the enclosing member may be blackened to facilitate radiation. Water is preferred as a liquid cooling medium, and the boiling point may be raised by the addition of salts. In the case of a gaseous medium, gases which would form explosive mixtures with the reactants are avoided. The process may be applied to the conversion of high boiling hydrocarbons into lower boiling hydrocarbons, using a catalyst consisting of ceramic material having adsorptive properties, if desired impregnated with finely divided metals or oxides. Preferably, the converter is arranged for the regeneration of the catalyst in situ by oxidation so that the reactions are alternately endothermic and exothermic. Specification 414,779 is referred to.