GB337380A - Improvements in cracking hydrocarbon oils - Google Patents

Abstract

337,380. Triggs, W. W., (Panhandle Refining Co.). June 29, 1929. Hydrocarbons, cracking.-In a process for ,cracking oils under reduced pressure, the oils are heated in a primary heating zone under suitable pressure at or above atmospheric and are then admitted to a flashing zone maintained under sub-atmospheric pressure, and the resulting vapours are passed to a cracking zone also under sub-atmospheric pressure. The crude oil is initially forced by a pump 54 through a preheating coil 57 into a flash pot 1 maintained at about 12-14 lbs. absolute pressure where the oil is vapourized and the vapours are passed through a cracking coil 56 at 1000-1200‹ and about 6-14 Ibs. pressure. The cracked vapours pass through a separating tower 6 and bubble towers 7, 8 where their temperature is controlled bv contact with cooling coils 26, 26<1>, 26<11>, 26<111>, 27, 28 through which the condensate from the towers 7, 8 is forced by pumps 13, 15 respectimely. Condensate from the tower 7 can also be injected into the tower 6 through a valve 18. The vapours from the tower 8 pass through a condenser 9 to a separator 10 from which condensate is withdrawn through a valve 29. The vacuum in the various parts of the system is determined by a pump 14 which withdraws vapours from the cracking zone through a line 40 and pumps them to the tower 6 through a line 39 or withdraws gases and uncondensed vapours 'from the separator 10 through a line 30 and pumps them through a line 42 to an absorption tower 11 supplied with washing liquid in the form of condensate withdrawn from the bottom of the tower 8. The condensate collecting at the bottom of the tower 11 is pumped by a pump 16 through a heat exchanger 17 and valve 33 into the middle of the tower 8. Burners 61 are provided in the upper portion of the furnace 2 as well as burners 62 in the lower zone, the burners' 61 being turned down after the plant is on flow, the coil 57 then being heated by waste gases of combustion passing through the perforations 63. In another construction the coils 56, 57 are arranged side by side and are separated by a wall. The burners 62 may be placed in arched side extensions of the zone 2 to avoid overheating the coil 56.