| 摘要 |
<p><PICT:0592446/IV/1> In the isomerization of normal paraffins by passage in the vapour phase through a bed of aluminium halide on a porous carrier, fresh aluminium is added only to that part of the bed separated from the feed inlet by the aluminium halide-hydrocarbon sludge formed, the feedstock thereafter being passed through the whole bed. A paraffin feed such as n-butane is fed through heater 13 and aluminium chloride pick-up vessel 17 to reactor 20 at about 200-350 DEG F., entering by line 18 below a grid 22 supporting a porous bed 21, for example of activated bauxite, for absorbing the aluminium chloride. When impregnation is sufficient, the vessel 17 is byepassed, and butane fed direct to reactor 20, a promoter such as hydrogen chloride being added from line 25. Impurities in the feed form a sludge in the lowest part 28 of the bed 21. Isomerization products leave at 27 for recovery. Reactivation of the catalyst is effected by addition of aluminium halide from vessel 17 in the butane stream, section 28 being byepassed by closing valve 19, and opening valve 29 in line 30. Butane only is then fed through the catalyst via line 18 and valve 19, the section 28 acting as a purifier. Periodically, this section may be reactivated with small amounts of aluminium chloride. If the sludge reaches above grid 31, make-up aluminium chloride may be introduced at progressively higher levels through valves 32 or 36, and the isomerization feed through valves 35 or 38. Inert gas may replace the butane for introducing make-up aluminium chloride whereby the upper part of bed 21 is kept sludge free. Impurities may be added to the feed hydrocarbons to hasten formation of sludge in section 28.</p> |
