GB484527A - A process of hydrocarbon oil conversion - Google Patents

Abstract

<PICT:0484527/III/1> In cracking process of the kind in which oils are cracked in the vapour phase by admixture with hot carrier gases, the residual gas, after separation of motor fuel fractions, is compressed, subjected to absorption with oil to separate lean gases, comprising chiefly hydrogen and methane and ethane, from rich gases which are absorbed, the lean gases being returned to the conversion cycle while the enriched oil is distilled to remove the rich fraction which is then subjected to polymerization with the recovery of a polymerized product suitable as a motor fuel. Crude oil is heated in a coil 14 and passed into a flash drum 15 where it is vaporized and mixed with the carrier gases from a line 62. The mixture is heated to 950-1050 DEG F. in coils 10 and passed into a soaking chamber 21 where the cracking reaction is completed. The products pass to a fractionator 23 from which heavy residue is withdrawn through a line 24 and through which an intermediate fraction is recycled through lines 28, 26 and a heat exchanger 27. Products in the gaseous state pass off through a line 32 through a cooler 33 to a receiver 34 where the gasoline product is separated and used in part as reflux for the tower 23. The gases are then compressed in a compressor 40 and passed through a cooler 41 to a receiver 42 where liquid components are separated. The gases pass to an absorption tower 44 through which a suitable absorption oil, e.g. a heavy gasoline condensate, is circulated from a line 46a The absorbed lean gases are evacuated through a line 61 while the rich gases are absorbed in the oil which is passed to a still 48 under pressure from which any unstable light fractions are removed and thence with reduction of pressure into a still 50 where the rich gases are boiled off, the stripped oil being recirculated to the line 46a. The rich gases are compressed by a pump 53 and passed to a coil 52 where they are polymerized under a pressure of about 3000 lb. per sq. inch, the products passing through a cooler 55 to a receiver 56 where the liquid components are collected the gaseous products being recycled through a line 57 to the absorber 44. The lean gasses passing off through the line 61 are recycled in part as the carrier gas to the line 62.