Improved process for the regeneration of catalysts used in reforming hydrocarbons

摘要

PICT:0600802/III/1 In reforming hydrocarbons in presence of a reforming catalyst and added hydrogen at superatmospheric pressure with periodic regeneration of the catalyst, the same is subjected after regeneration to a purging operation with hydrogen or hydrogen-containing gas at a pressure substantially less than that of the reforming. A virgin naphtha may, for example, be heated above 950 DEG F. in heater 5 and fed by line 10, together with hydrogen from line 11 to converter 12 containing trays of catalyst, preferably molybdena on activated alumina. Pressure is preferably 150-400 p.s.i. The product leaves by line 20, gases containing hydrogen being recovered in separator 42 and recycled by line 30 to line 11, if desired after removing hydrocarbons. Bottoms pass by line 43 to fractionator 44 where the desired product is recovered, bottoms being recycled, and overhead treated to recover hydrogen for re-use. Catalyst regeneration is effected by closing valve 31, purging with hydrogen or recycled gas fed through line 33 and leaving by line 35, and the injecting air, preferably at 600-700 DEG F., from line 41 at a pressure about the same as that used in the reforming whereby deposits are burnt off the catalyst which is at a temperature of about 900 DEG F. The inert flue gases leave by pipe 35 or may be in part recycled by line 46, with additional flue gas from line 41. Pressure is now reduced to atmospheric by taking off flue gas, preferably over a period of 5-15, say 6 minutes, when valve 32 is opened and recycle, hydrogen-containing gas is passed through the converter 12 for about 30 minutes and discarded through line 35. At the end of this period, no hydrogen should be consumed by the catalyst. The valve in line 35 is now closed and recycle gas pumped into the converter for about 8 minutes until the reaction pressure is again reached. The purging may, however, be effected at sub-atmospheric pressure or up to about 50 p.s.i.ALSO:PICT:0600802/IV(b)/1 In reforming hydrocarbons in presence of a reforming catalyst and added hydrogen at superatmospheric pressure with periodic regeneration of the catalyst, the same is subjected after regeneration to a purging operation with hydrogen or hydrogen-containing gas at a pressure substantially less than that of the reforming. A virgin naphtha may, for example, be heated above 950 DEG F. in heater 5 and fed by line 10 together with hydrogen from line 11 to converter 12 containing trays of catalyst, preferably molybdena on activated alumina. Pressure is preferably 150-400 p.s.i. The product leaves by line 20, gases containing hydrogen being recovered in separator 42 and recycled by line 30 to line 11, if desired after removing hydrocarbons. Bottoms pass by line 43 to fractionator 44 where the desired product is recovered, bottoms being recycled, and overhead treated to recover hydrogen for re-use. Catalyst regeneration is effected by closing valve 31, purging with hydrogen or recycled gas fed through line 33 and leaving by line 35, and then injecting air, preferably at 600-700 DEG F., from line 41 at a pressure about the same as that used in the reforming, whereby deposits are burnt off the catalyst which is at a temperature of about 900 DEG F. The inert flue gases leave by pipe 35 or may be in part recycled by line 46, with additional flue gas from line 41. Pressure is now reduced to atmospheric by taking off flue gas, preferably over a period of 5-15, say 6 mins., when valve 32 is opened and recycle, hydrogen-containing gas is passed through the converter 12 for about 30 mins. and discarded through line 35. At the end of this period, no hydrogen should be consumed by the catalyst. The valve in line 35 is now closed and recycle gas pumped into the converter for about 8 mins. until the reaction pressure is again reached. The purging may, however, be effected at sub-atmospheric pressure or up to about 50 p.s.i. The invention is illustrated by the conversion of methylcyclohexane to toluene.