Patent GB-784894-A (GB)
Title: Improvements relating to the regeneration of contact materials
IPC: B01J8/12
Filed: 1955-09-23
Abstract: Granular materials used in the catalytic conversion of hydro carbons are regenerated in two stages: (1) in a pre-burning zone in which the contaminated catalyst and air flow concurrently and the volatile combustible materials are removed; (2) then in a regenerating zone in which the catalyst passes downwards in countercurrent with air, and the heavier coke deposits are burnt off.  The gases finally discharged into the atmosphere are free from "smoke plume."  In a suitable apparatus, an insulated regenerator 11, Fig. 1, is divided into a regenerating zone 14 and an upper pre-burning zone 12 by a header box 18 which is of pentagonal shape in plan and is spaced from the inner wall of the regenerator so that gases formed in the lower zone can pass upwards through the main body of the catalyst in the regenerating zone, and thence to the exhaust 23.  The header box 18 is formed by plates 15, 19 and end walls 76 to form a gas manifold connected to an air inlet 17.  Air is discharged downwards from the gas manifold <PICT:0784894/III/1> <PICT:0784894/III/2> through a number of pipes 20 at the top of the regenerating zone, and passes concurrently with the main body of the gravitating catalyst to burn off the heavy contaminant, the resulting flue gas passing around the header box to the exhaust 23.  The upper pre-burning zone comprises vertical outer walls 26, Fig. 3, arranged as a pentagon in plan, closed at the upper end by a sheet 33 provided with an inlet 10, and at the lower end by two sheets 31, 32 spaced apart and provided with a number of tubes 36 passing therethrough.  The space between the two sheets is supplied with air from a surrounding manifold 27 provided with an air inlet 28. Pipes 36 are mounted in an annular opening 39 so that air can pass into the upper space to which the contaminated catalyst is fed from the inlet 10.  In operation, the used catalyst at a temperature of about 700-1100 DEG  F. is fed on to the sheet 31 from which it falls through tubes 36 and a larger control overflow pipe 37 with air flowing concurrently, and into the space 12, Fig. 1, defined by a hood 13.  The walls of the hood are inclined at an angle steeper than the normal angle of repose of the catalyst heaped upon the header box 18 between walls 21.  The more volatile constituents are burnt off in the preburning zone, assisted by additional air fed through tubes 38 if necessary.  The products of combustion pass to the exhaust 23.  The heaped material then flows through pipes 16 in a compact mass on to the bed of gravitating material in the lower regenerating zone.  The lower ends of the pipes 16 are immersed in the bed to prevent upward flow of gas therein, but allow a free zone between the top of the bed and the bottom of the header box to assist release of gases and air from the bed.  Air flowing downwards from tubes 20 and reflected upwards from the bottom of the chamber, burn off the heavier carbonaceous materials, and the regenerated catalyst is removed at the bottom.  In a modification (not shown) of the pre-burning zone, the hood 13 is secured to the upper sheet 15 of the header box 18, and the lower openings of pipes 16 are provided with cup-shaped members.  Catalyst-materials specified are bauxite, alumina, silica, alone or impregnated with metal oxides.