GB353148A - Process and apparatus for treating oils - Google Patents

Abstract

In a continuous process for converting heavy oils into light ones in which the heavy oil is first distilled to form a condensate, part of which is cracked in a heated coil, the remainder of the condensate is introduced at substantially lower temperature (e.g. 55-65 DEG C.) into the hottest point of the cracking coil to prevent undue decomposition of the oil. Crude oil from a storage tank 1 is pumped through heat exchangers 7, 10 to vaporizing coils 12, 13 situated at the top of the furnaces 14, 15 and the products are led through a line 16 into an evaporator 17 terminating in a bubble tower 19. The vapours passing off at the top of the tower through a pipe 20 are led to a condenser 21 and <PICT:0353148/III/1> the condensate is recycled through a line 75 as reflux. The condensate collecting in a liquid trap 18 is directed through a cooler 30 to a receiver 31 from which a portion thereof is pumped through heat exchangers A, B, C and pipe 38 to the cracking coils 39, 40. The remainder is pumped through a line 51 into the hottest portion of the cracking coils through valved inlets 52<1>, 52<11> and also into the transfer line 41 through an inlet 53<1>. The cracked products pass through the line 41 into a reaction drum 42 or may be byepassed by a line 69 and thus flow through the heat exchanger C into a bubble tower evaporator 45, 46 similar in construction to the tower 19. The vapours pass off through a pipe 47 to a condenser 48, the condensate being collected in a receiver 50 from which a part thereof may be recycled as reflux by the pump 78 to the tower 46. The liquid residue in the evaporator 45 is pumped through the heat exchanger B to a storage tank 62, while condensate in the trap 70 is delivered through a cooler 56 to a tank 57 from which it is recycled through a line 58 for admixture in the pipe 34 with the condensate from the tank 31. The coils may be cleaned from deposits by flushing them with water from a tank 63. The oil in the coils 12, 13 is heated to about 260 DEG C., while in the coil 40 the oil is heated to about 480 DEG C. but the temperature is reduced to about 425 DEG by the addition of cooler oil. The cracking temperature is attained in the coil 39, the coil 40 being heated to supply the endothermic heat of the reaction.