Patent GB-842723-A (GB)
Title: Hydrocarbon conversion process
IPC: C10G35/04
Filed: 1956-10-15
Abstract: In a process for the conversion if a nitrogen-containing hydrocarbon distillate such as naphtha or gas oil, or a catalytic cycle oil, which may contain up to 500 ppm. of nitrogen, into gasoline of relatively high octane rating by passing the feedstock together with hydrogen (at least 1500 SCF per barrel of oil) at a pressure of at least 600 p.s.i.g. over a hydrogenation-dehydrogenation catalyst deposited on an active cracking support contained in a reaction zone maintained at a temperature of from 700 DEG  to 850 DEG F., wherein the hydrogen-rich gas separated from the effluent from the reaction zone is recycled to it, poisoning of the catalyst by ammonia is obviated by washing the whole effluent or only the recycle gas stream with water, or by passing the recycle gas over an acid absorbed on a porous carrier, in order to remove ammonia from the gas before it is recycled.  In an example, a hydrofined cracked naphtha, boiling between 340 DEG  abd 455 DEG F., containing 2,8 ppm. of nitrogen and having an octane rating of 58, is introduced together with a hydrogen-rich gas stream (6000 SCF per bbl. of naphtha) into a reaction zone which contains a catalyst comprising molybdenum oxide and cobalt oxide deposited on a synthetic silica-alumina catalyst in the form of beads.  The reaction conditions are a temperature of 700 DEG -750 DEG F., a pressure of 1200 p.s.i.g., and a liquid hourly space velocity of 2.  The effluent from the reaction zone is mixed with water (about 1 lb. per bbl. of effluent); and the resulting mixture is passed through a cooler to a gas-liquid separator.  A gas stream containing approximately 90% of hydrogen and substantially free of ammonia, is withdrawn from the separator, and recycled to the reaction zone.  An aqueous phase is withdrawn from the separator to waste.  The liquid hydrocarbon phase, withdrawn from the separator, is passed to a second gas-liquid separator, which is operated at atmospheric pressure, in order to eliminate C4 and lower boiling components.  The liquid withdrawn from the second separator is fractionated to obtain a C5-350 DEG F. gasoline having an octane rating of about 88.  The high-boiling fractionation bottoms are recycled to the reaction zone.  The fractionation may be so conducted as to recover a light gasoline (C5-165 DEG F.) and an intermediate gasoline (165 DEG -350 DEG F.).  The latter may then be passed, along with added hydrogen, through a platinum reforming catalyst at temperatures between 800 DEG  and 1000 DEG F. and pressures of 200 to 900 p.s.i.g.  The hydrogen produced in the reforming zone is recovered from the effluent from that zone and introduced into the main reaction zone.ALSO:In a process for the conversion of a nitrogen-containing hydrocarbon distillate such as naphtha or gas oil, or a catalytic cycle oil, which may contain up to 500 ppm. of nitrogen, into gasoline of relatively high octane rating by passing the feedstock together with hydrogen (at least 1500 SCF per barrel of oil) at a pressure of at least 600 psig. over a hydrogenation - dehydrogenation catalyst deposited on an active cracking support contained in a reaction zone maintained at a temperature of from 700 DEG  to 850 DEG F., wherein the hydrogen-rich gas separated from the effluent from the reaction zone is recycled to it, poisoning of the catalyst by ammonia is obviated by washing the whole effluent or only the recycle gas stream with water, or by passing the recycle gas over an acid absorbed on a porous carrier, in order to remove ammonia from the gas before it is recycled. The catalyst may be an oxide or sulphide of molybdenum, tungsten, vanadium or chromium, a metal such as iron, nickel, cobalt or platinum, or various oxides thereof.  In an example, a catalytic cycle oil having a B.R. of 429 DEG -541 DEG F. and containing 0.74% by weight of sulphur and 600 ppm. of nitrogen is hydrofined by passing it at a temperature of 770 DEG F. and a pressure of 800 psig. along with 3000 to 6000 SCF H2 per bbl. of feed through a catalyst containing molybdenum oxide and cobalt oxide deposited on alumina.  The resulting material is fractionated so as to strip off hydrogen sulphide and ammonia gases, yielding an oil having a B.R. of 356 DEG -544 DEG F. and containing 73 ppm. of nitrogen.  This hydrofined oil is now passed, along with 7000 SCF H2 per bbl. of oil, at a temperature of 775 DEG F. and a pressure of 1200 psig. through a reaction zone containing 0.3% of platinum deposited on a synthetic silica-alumina gel in the form of beads, the liquid hourly space velocity being maintained at a value of about 2. The effluent is passed through a cooler and then into a gas-liquid separator.  The hydrogenrich gas stream, which is withdrawn from the separator, is passed through a bed comprising H3PO4 absorbed on kieselguhr, and is then recycled to the reaction zone.  The liquid hydrocarbon phase withdrawn from the separator is passed to a second separator maintained at atmospheric pressure, for elimination of C4 and lower boiling components.  The liquid hydrocarbon phase is then submitted to fractionation whereby a C5-390 DEG F. gasoline is recovered having an octane rating of 85.5.  The fraction boiling above 390 DEG F. is recycled to the reaction zone.  The fractionation may be so conducted as to recover an intermediate gasoline fraction which is then passed, along with added hydrogen, through a platinum reforming catalyst at temperatures between 800 DEG  and 1000 DEG F. and pressures of 200 to 900 psig.  The hydrogen produced in the reforming zone is recovered from the effluent from that zone and introduced to the main reaction zone.