GB422971A - An improved process and apparatus for cracking hydrocarbons - Google Patents

Abstract

In a process for cracking oils, coal tars, &c. the starting material is preheated under 10--100 atmospheres pressure without distillation to a temperature below the cracking point, the light ends are removed by expansion, and the heavy ends non-destructively distilled to remove pitch and the like, the distillate thus obtained being then cracked. Light oil containing resinifying constituents, and benzene from distillation gases, may be mixed with the crude oil prior to the preheating. Crude oil is supplied from a container 1 to a container 3 where it may be mixed with light oil from a container 2, and is fed by a pump 4 at a pressure of 11--16 atmospheres through a coil 5 in a furnace 6. The oil at about 300--400 DEG C. passes through a pressure-reducing valve 7 into a separator 8 from which the vaporizable constituents pass to a dephlegmator 9 from the upper part of which vapours pass to a condenser 10. The crude benzine is separated in a vessel 11 from water which flows away at 33, and is collected in a receiver 12. The condensate from column 9 passes through cooler 14 to collecting vessels 15, 15<1>. The non-volatile components are led from chamber 8 through a siphon vessel 16 to one of the stills 17<1>, 17<11> in which they are non-destructively distilled under vacuum produced by a pump 22. Asphalt or pitch are run off to a collecting vessel 18. The vapours are fed to a condenser <PICT:0422971/III/1> 19 and the condensate passes through containers 20, 21 to one of vessels 15, 15<1> from which it supplied to the cracking coils 24<1>, 24<11> in furnace 6 under a pressure of about 40--80 atmospheres by a pump 23. The oil flows in coil 24<1> in the opposite direction to, and in coil 24<11> in the same direction as, the heating gases, and to maintain the conversion temperature in coil 24<11> additional heating may be provided or air or heating gases or a mixture of both may be supplied through openings 25. The cracked products flow through a pressure reducing valve 26 into the separating chamber 8. Valves 30, a cooler 31 and a collecting vessel 32 are provided for emptying the apparatus.