GB790166A - Improvements in or relating to processes and apparatus for effecting a rapid change in temperature of gaseous fluid or for rapidly vaporising liquid fluid - Google Patents

Abstract

Allyl chloride is formed by the reaction of propene with chlorine at about 500 DEG C., using a process in which a rapid change in temperature of a gaseous fluid is effected by passing the fluid through a screen of free-falling solid particles of size less than 2 mm., which screen is formed by flow of particles from a homogeneously fluidized bed, the temperature of which is considerably different from that of the fluid (see Group III).ALSO:<PICT:0790166/III/1> A rapid change in temperature of a gaseous fluid is effected, or a liquid fluid is rapidly vaporized, by passing the fluid through a screen of free-falling solid particles of size less than 2 mm., which screen is formed by flow of particles from a homogeneously fluidized bed, the temperature of which is considerably different from that of the fluid. The solids fall through a straight or circular slot at the top of a vessel to form a flat or cylindrical screen; a collecting device for the solid is provided at the foot of the vessel and an inlet for the fluid leads into one of the spaces into which the vessel is divided by the screen. The process may be used for the rapid heating of reactants, for the cooling of reaction products, or for controlling the temperature of endothermic or exothermic reactions. Liquid or gaseous hydrocarbons may be cracked by contact with solids which are either inert, e.g. sand, or catalytic; the reaction products may be cooled by introducing a quenching medium into the outlet from the vessel or by passing the products through a second screen of cooled solids. When reactants are to be heated separately, two screens of hot particles may be used, one for each reactant. As shown, hot particles flow from fluidized bed in vessel 5 through slot 15 to form screen 16, being collected in a fluidized bed in vessel 6. The fluid to be treated is supplied through nozzle 17 and passes through screen 16 to outlet 13 and cyclone 35. Solid collects in vessel 38 and is withdrawn at 39 for heating, regenerating if necessary, and return to vessel 5. Heating and regeneration may be carried out by a process according to the invention, the solid being treated as a falling screen with fuel and combustion air. Solid paraffin-containing substances may be converted into ethene or a mixture of olefins at 700-800 DEG C. in the presence of steam and in some cases oxygen. Other reactions referred to are the conversion of methane by steam into carbon monoxide and hydrogen; the conversion of methane by oxygen into ethyne or aromatics; the oxidation of ammonia to nitrogen oxides at 700-1000 DEG C.; the conversion of alkanes to alkenes; the formation of allyl chloride from propene and chlorine at 500 DEG C.; the pyrolytic aromatization of alkanes at 750-900 DEG C.; the reaction between methene, ammonia and oxygen in the presence of platinum catalyst to form hydrogen cyanide; and the reaction between methane and nitrogen oxide at 1000 DEG C. to form hydrogen cyanide.