Patent GB-723491-A (GB)
Title: Improvements in or relating to fluidised-hydroforming
IPC: C10G35/14
Filed: 1952-10-16
Abstract: In a process for hydroforming hydrocarbons boiling within the motor-fuel range in which the hydrocarbons are contacted in a hydroforming zone at elevated temperature with a dense, turbulent bed of finely divided particles of hydroforming catalyst in the presence of hydrogen and catalyst particles are withdrawn from the hydroforming zone and transferred to a regeneration zone wherein the carbon content of the catalyst particles is reduced and are then returned to the hydroforming zone, the regenerated catalyst particles are contacted with a high-velocity stream of hot hydrogen-rich gas, for a period not exceeding 10 seconds, the catalyst particles are separated from the hydrogen-rich gas and then returned to the main fluidized bed of catalyst in the hydroforming zone.  The feed to the hydroforming reactor may be a p  virgin naphtha, a cracked naphtha, or a Fischer-Tropsch naphtha and is preheated alone or in admixture with recycle gas, ordinarily to about 800-1050 DEG  F.  The recycle gas which contains about 50 to 70 volume per cent hydrogen is preheated to about 1150-1300 DEG  F. prior to its introduction to the reactor.  The recycle gas should be circulated through the reactor at about 1000 to 8000, preferably about 4000 cubic feet per barrel of naphtha feed.  Suitable catalysts for the reaction include Group VI metal oxides such as molybdenum oxide, chromium oxide, or tungsten oxide, or mixtures thereof, upon a carrier such as activated alumina, alumina gel, or zinc aluminate spinel.  If desired minor amounts of stabilizers and promoters such as silica, calcium oxide, ceria, or potassia can be included in the catalyst and the catalyst particles are mostly between 20 and 80 microns in diameter.  The hydroforming reaction should be conducted at between 850 DEG  and 950 DEG  F. and at pressures between 50 and 500 pounds per square inch.  The regenerator should be operated at essentially the same pressure as the reactor and at temperatures of about 1050-1300 DEG  F.  The residence time of the catalyst in the reactor may be 3 to 4 hours while the residence time in the regenerator may be from 3 to 15 minutes.  The superficial velocity of the gaseous or vaporous materials through the reaction and regeneration zones is preferably about 0.2 to about 0.9 feet per second whilst the weight ratio of catalyst to oil introduced into the reactor should preferably be about 0.5 to 1.5.  Space velocity for a molybdenum oxide on alumina gel catalyst may be from 1.5 to 0.15 pounds of feed charged per pound of catalyst in the reactor. Two methods of carrying out the invention are described and illustrated.  In one method the mixture of hot regenerated catalyst and hydrogen-rich or recycle gas is discharged into a cyclone separator in the upper part of the hydroforming zone to disengage the catalyst from the hydrogen-rich gas which is then discharged along with other gaseous products of the pretreatment into the dilute phase in the hydroforming reactor vessel or directly into a second cyclone separator to effect further separation of catalyst particles or to separate recovery or processing equipment.  In the other method the mixture of hot regenerated catalyst and hydrogen-rich or recycle gas is passed through a transfer line arranged within the hydroforming reactor vessel and is discharged against a baffle arranged just above the level of the dense bed of catalyst whereby the catalyst is separated and returns directly to the top of the dense bed of catalyst which serves to exert a cooling action on the mixture of regenerated catalyst and hydrogen-rich gas during its passage through the transfer line.  Tabulated data is given to show that when an amount of water vapour equivalent to that formed in the pretreatment of the regenerated catalyst with the hydrogen-rich gas is added continuously along with the hydrogen-containing gas entering the hydroforming zone the yield and octaine number of the product is lowered and the carbon yield increased.ALSO:In a process for hydroforming hydrocarbons boiling within the motor fuel range in which the hydrocarbons are contacted in a hydroforming zone at elevated temperature with a dense, turbulent bed of finely divided particles of hydroforming catalyst in the presence of hydrogen and catalyst particles are withdrawn from the hydroforming zone and transferred to a regeneration zone wherein the carbon content of the catalyst particles is reduced and are then returned to the hydroforming zone, the regenerated catalyst particles are contacted with a high velocity stream of hot hydrogen-rich gas, for a period not exceeding 10 seconds, the catalyst particles are separated from the hydrogen-rich gas and then returned to the main fluidized bed of catalyst in the hydroforming zone.  The feed to the hydroforming reactor may be a virgin naphtha, a cracked naphtha, or a Fischer-Tropsch naphtha and is preheated alone or in admixture with recycle gas, ordinarily to about 800-1050 DEG F.  The recycle gas which contains about 50 to 70 volume per cent hydrogen is preheated to about 1150-1300 DEG F. prior to its introduction to the reactor. The recycle gas should be circulated through the reactor at about 1000 to 8000, preferably about 4000 cubic feet per barrel of naphtha feed.  Suitable catalysts for the reaction include Group VI metal oxides such as molybdenum oxide, chromium oxide, or tungsten oxide, or mixtures thereof, upon a carrier such as activated alumina, alumina gel, or zinc aluminate spinel.  If desired minor amounts of stabilizers and promoters such as silica, calcium oxide, ceria, or potassia can be included in the catalyst and the catalyst particles are mostly between 20 and 80 microns in diameter.  The hydroforming reaction should be conducted at between 850 and 950 DEG F. and at pressures between 50 and 500 lbs. per square inch.  The regenerator should be operated at essentially the same pressure as the reactor and at temperatures of about 1050 -1300 DEG F.  The residence time of the catalyst in the reactor may be 3 to 4 hours while the residence time in the regenerator may be from 3 to 15 minutes.  The superficial velocity of the gaseous or vaporous materials through the reaction and regeneration zones is preferably about 0.2 to about 0.9 feet per second whilst the weight ratio of catalyst to oil introduced into p the reactor should preferably be about 0.5 to 1.5.  Space velocity for a molybdenum oxide on alumina gel catalyst may be from 1.5 to 0.15 pounds of feed charged per pound of catalyst in the reactor. Two methods of carrying out the invention are described and illustrated. In one method the mixture of hot regenerated catalyst and hydrogen-rich or recycle gas is discharged into a cyclone separator in the upper part of the hydroforming zone to disengage the catalyst from the hydrogen-rich gas which is then discharged along with other gaseous products of the pretreatment into the dilute phase in the hydroforming reactor vessel or directly into a second cyclone separator to effect further separation of catalyst particles or to separate recovery or processing equipment.  In the other method the mixture of hot regenerated catalyst and hydrogen-rich or recycle gas is passed through a transfer line arranged within the hydroforming reactor vessel and is discharged against a baffle arranged just above the level of the dense bed of catalyst whereby the catalyst is separated and returns directly to the top of the dense bed of catalyst which serves to exert a cooling action on the mixture of regenerated catalyst and hydrogen-rich gas during its passage through the line.  Tabulated data is given to show that when an amount of water vapour equivalent to that formed in the pretreatment of regenerated catalyst with the hydrogen-rich gas is added continuously along with the hydrogen-containing gas entering the hydroforming zone the yield and octane number of the product is lowered and the carbon yield increased.