GB610080A - Catalyst preparation - Google Patents

Abstract

<PICT:0610080/III/1> Spheroidal particles for use in fluid catalyst reaction systems are produced by forming a spheroidal liquid or gelatinous coating of a catalytic material about solid particles of a size less than 40 microns which are maintained in a dispersed state, and maintaining the droplets in a gaseous atmosphere to solidify the coating. The particles may be spent or active catalytic fines, whether in spheroidal or granular form, or material such as bauxite, silica, sand, pipe clay, meerschaum, montmorillonites, fuller's earth, bentonite, majolica, chamotte, pumice, concrete, alumina, "Permutit" (Registered Trade Mark), or high heat capacity material such as carborundum, iron oxide, pyrites, galena, barytes, hematite, and metal and alloys such as steel, iron, bronze, brass, silicon bronze nickel, copper, aluminium, with their surfaces polished or etched with acids, if desired. Impurities may be first removed from the fines. The catalyst material may be the oxides, sulphides or oxysulphides of iron, chromium, bismuth, boron, aluminium, gallium, copper, nickel, beryllium, titanium, indium, zirconium, thorium, cerium, scandium, vanadium, manganese, magnesium, silicon, lanthanum, germanium, tin, tantalum, molybdenum, tungsten, or mixtures. The production of stannous oxide, titanate, tungstic oxide, alumina and silica gels is exemplified. A sol containing the fines may be sprayed into an atmosphere containing a coagulating agent, or the fines together with a solution containing one ingredient of the sol or gel desired may be sprayed into an atmosphere of the other component; for example, a slurry of fines and sodium silicate may be sprayed into hydrochloric acid vapour. The fines may be wetted prior to mixing, if desired with the aid of a wetting agent. The coated particles may be dried completely either in the spraying process, for which temperatures of 200 DEG to 1500 DEG F. are mentioned, or after spraying, in a rotary kiln. The size of the dried particles may be from 20 to 3000 microns. Several layers of the same or different coating material may be produced. For the production of a silica-alumina catalyst, silica sol and gel, and aluminina sol and gel are mixed in vessel 9, filtered and washed at 13, and mixed in vessel 14 with silica-alumina fines. The mixture is pumped to a sprayer disc or cone 19 or other atomizer, and the droplets, deflected by plate 22, are dried by hot air or flue gas from conduit 23 and pass through rotary drier 26 to store 28. Fines removed by cyclone separator 31 and electrostatic precipitator 41 may be returned through line 34 to vessel 14. Other examples of catalyst and supporting materials are specified. Specification 590,252 is referred to.