GB495477A - Process for the conversion of hydrocarbon mixtures - Google Patents

Abstract

<PICT:0495477/III/1> Normally liquid or solid hydrocarbon materials of predominantly paraffinic character, e.g. a paraffin base stock containing hydrocarbon wax or a paraffinic hydrocarbon distillate, are converted into olefinic products suitable for polymerization into lubricating stocks by vaporizing the hydrocarbon materials and immediately without separation subjecting the vapours to cracking in a plurality of parallel connected tubular elements directly connected to the tubular vaporizing zone in which additional heat is supplied to produce substantial yields of olefines, abruptly reducing the temperature of the cracked products by direct contact with a cooling fluid, and recovering the olefinic products by fractional condensation. Crude material with or without passage through the lower evaporating zone 49 of a tower 47 is passed through a vaporizing coil 10, where it is preferably mixed with superheated steam from a coil 13, to a series of parallel connected tubular cracking coils 19. The cracked vapours are passed through lines 26, 28, in which they are cooled by water from a separator 55 fed through line 59 and by crude oil fed through lines 6, 106, to a flash chamber 42 from which residuum is removed through cooler 33 to receiver 36, part of the residuum being recirculated through line 40. The separated vapours flow through line 45 into the evaporator 49 and together with vaporized fractions of the crude oil pass into the upper fractionating zone 48 of the tower 47 from which the desired lightfractions are taken through line 51 and cooler 53 to separator 55. Reflux collecting on the plate 50 together with part of the bottoms from the evaporator 49 are recycled through lines 93, 96 to the coil 10 or the evaporator 42, or may be fed through a cooler 981 to a tank 100 from which they are fed to the evaporator 49 as required. The remainder of the bottoms from the evaporator are drawn off through cooler 73 to receiver 76 and pumped (a) through line 82 back to the evaporator, (b) through line 83 into the flash chamber 42, (c) through line 83 to mix with the cracked vapours in line 28. In treating a soft paraffin wax of m.p. 59,5 DEG C. the following temperatures were employed: .. DEG C .Exit of primary vaporizer.465 .Steam to inlet of secondary heater.620 .Inlet of secondary heater.445 .Exit from secondary heater.551 .After quenching by water.472 In treating Kogasin (product of the catalytic reaction of carbon monoxide and hydrogen) the following temperatures were employed: .. DEG C .Combined feed to vaporizer.243 .Steam to last turn of vaporizer coil.372 .Exit of cracking coil.560 .After quenching by mixing with reflux.426 .Residuum withdrawn at.393 .Residuum cooled to.204 .Top of flash chamber.354 .Top of fractionating tower.136