GB552413A - Improvements in or relating to the treatment of hydrocarbons - Google Patents

Abstract

552,413. Polymerized hydrocarbons. STEVENS, A. H. (Phillips Petroleum Co.). March 29, 1940, No. 5721. [Class 2 (iii)] Olefines having not more than five carbon atoms in the molecule are converted into volatile polymers by being passed alone or together with paraffins containing more than five carbon atoms over a solid polymerisation catalyst. Such pressures and temperatures are used that the reactants are kept substantially in the liquid phase and a portion of the untreated products is mixed with the olefinic feed and returned to the reaction zone. In a modification, active olefines such as isobutylene or branched amylenes are polymerised in a separate catalytic chamber before the remaining gases are treated. Catalysts mentioned are hydrous silica impregnated with aluminium chloride and fullers earth and hydrous silica associated with alumina. In the Figure hydrocarbons containing olefines enter a fractionating column 1 at a sufficient pressure to maintain substantially the whole of the olefines in solution in the liquid descending the column. Vapours which are withdrawn pass through a condenser 2, the condensed hydrocarbons being withdrawn through a separator and pipe 4 and, after mixing with a hot fraction taken by means of pipe 5 from the column 1, in part returned to the latter and in part passed to a catalytic chamber 7. When column 1 contains a high proportion of hydrocarbons of low molecular weight requiring high pressures it may be necessary to pass the gases coming from the column through a heater 11. The products of the polymerisation, still in the liquid state enter the column through pipe 8, the amount of higher non-volatile polymers being reduced by recycling part of the products by means of pump 9. The second catalytic chamber 13 is used when branched lower olefines are present in the hydrocarbons employed. Inert paraffins such as naphtha or gasoline may be introduced through pipe 14. Specification 536,528 is referred to.