Patent GB-688592-A (GB)
Title: A process for converting high boiling strongly paraffinous hydrocarbon distillates into valuable products
IPC: C10G9/00
Filed: 1951-04-04
Abstract: Hydrocarbon distillates having an initial boiling point above 250 DEG C. and consisting predominantly of paraffinic hydrocarbons (i.e. less than 20 per cent of the carbon present being in ring formation), are converted into straight-chain alpha alkenes, gasoline and gas oil, by subjecting the distillate to thermal cracking in the vapour phase at a temperature above 500 DEG  C. for a period of time not greater than 10 seconds, distilling from the thermallycracked product a fraction or fractions rich in the alkenes, and submitting the distillation-residue to catalytic cracking to obtain gasoline and gas oil.  The alkenes may be used for the preparation of aldehydes and ketones by means of the Oxo process, of synthetic lubricating oils by polymerization or by alkylation of aromatics, and of detergents by sulphating, followed by neutralization of the acid monoalkylsulphates obtained with a caustic solution.  In an example, a distillate of crude Tandjung oil (B.R. 332-494 DEG  C.) containing 60 per cent of paraffin wax, was evaporated with steam at 440 DEG  C., quickly heated to 530 DEG  C., and kept for 4 seconds at this temperature. The product obtained was quickly cooled to 150 DEG  C., and the fraction which remained uncondensed was further cooled to 20 DEG  C. The total condensate was then subjected to fractional distillation to give the following fractions: C5-C7 hydrocarbons (3.5 per cent), C8-C13 (6.5 per cent), C14-C18 (5 per cent), and distillation-residue (76.5 per cent).  The first three fractions contained 85 per cent alkenes.  The residue was submitted to cracking at 482 DEG  C. using a fluidized bed of synthetic Al2O3-SiO2 catalyst, the cracking time being 15 minutes.  The cracked product was cooled, and separated by distillation into the following fractions, the percentages being based on the distillate used as starting material: gas (6 per cent), butanes-butenes (10 per cent), gasoline (25 per cent), gas oil (33 per cent).ALSO:Hydrocarbon distillates having an initial boiling point above 250 DEG C and consisting predominantly of paraffinic hydrocarbons (i.e. less than 20 per cent of the carbon present being in ring formation), are converted into straight-chain alpha alkenes, gasoline and gas oil, by subjecting the distillate to thermal cracking in the vapour phase at a temperature above 500 DEG C for a period of time not greater than 10 seconds, distilling from the thermally-cracked product a fraction or fractions rich in the alkenes, and submitting the distillation-residue to catalytic cracking to obtain gasoline and gas oil.  The paraffin wax content of the original distillate is greatly reduced in the thermal cracking stage, so that the distillation-residue is more suitable than the original distillate for catalytic cracking.  In an example, a distillate of crude Tandjung oil (B.R. 332 DEG -494 DEG C) containing 60 per cent of paraffin wax, was evaporated with steam at 440 DEG C, quickly heated to 530 DEG C, and kept for 4 seconds at this temperature.  The product obtained was quickly cooled to 150 DEG C, and the fraction which remained uncondensed was further cooled to 20 DEG C.  The total condensate was then subjected to fractional distillation to give the following fractions:-C5-C7 hydrocarbons (3.5 per cent), C8-C13 (6.5 per cent), C14-C18 (5 per cent), and distillation-residue (76.5 per cent).  The first three fractions contained 85 per cent alkenes.  The residue was submitted to cracking at 482 DEG C using a fluidized bed of synthetic Al2O3-SiO2 catalyst, the throughput being 2 parts by weight of oil per part by weight of catalyst per hour.  The cracking time was 15 minutes. The cracked product was cooled, and separated by distillation into the following fractions, the percentages being based on the distillate used as starting material:-gas (6 per cent), butanes-butenes (10 per cent), gasoline (25 per cent), gas oil (33 per cent).  The octane number of the gasoline was about 80.