FLUID CATALYTIC CRACKING SYSTEMS

• Main Authors: CHESSMORE, DONALD O, PETTERSEN, FREDERICK A
• Format: Patent
• Language: English; French
• Published: 01.03.1988
• Edition: 4
• Subjects: CHEMISTRY; CRACKING HYDROCARBON OILS; FUELS; LUBRICANTS; METALLURGY; MINERAL WAXES; PEAT; PETROLEUM, GAS OR COKE INDUSTRIES; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVEHYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, ORGASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; TECHNICAL GASES CONTAINING CARBON MONOXIDE

An improved liquid hydrocarbon feed method is disclosed wherein substantially all of the liquid is converted to mist sized particles over a wide angled dispersion pattern without a concurrent shroud of steam or water. Such dispersion promotes vapor phase catalytic reaction between hydrocarbon vapors and fluidized catalyst in a reaction time of 1 to 3 seconds. In a preferred form, the liquid feed is introduced into the transition section of a riser reactor. The misting nozzle is characterized by a swirl chamber to which the full hydrocarbon feed is supplied for centrifugal rotation by vane members and the flow is released through a reduced area orifice having a short throat to maintain a low pressure drop through the nozzle and a cylindrically confined stream flow into the riser reactor produces a wide angled conical dispersion pattern. Introduction of such a hydrocarbon dispersion into the reactor riser at high flow rate is maintained so that the liquid is substantially instantaneous vaporized. Coking of the feed nozzle is thus avoided without requiring assistance of steam or water flow therearound. Generation of misted hydrocarbon particles without steam or water substantially improves the economics of processing the resulting fluidized catalyting cracking products distilled from the evolved vapors by reducing sour (acid) water disposal. Coking in the feed nozzle is avoided by maintaining high liquid velocities in the nozzle. The large open area of the ports and exit orifice minimize the opportunity for physical plugging of the nozzle by coke or other foreign materials. Short straight cylindrical flow from the orifice allows the nozzle to be recessed out of the flowing catalyst stream. This keeps the nozzle cooler and minimizes mechanical erosion of the nozzle by the heated catalyst.