Patent GB-744429-A (GB)
Title: Regeneration of catalysts used in the catalytic treatment of hydrocarbons
IPC: B01J38/12
Filed: 1953-10-05
Abstract: In the catalytic reforming of hydrocarbons, the catalyst is regenerated in situ by periodically burning off carbonaceous deposits and then treating with hydrogen, the hydrogen being introduced at a place such that it does not come into contact with material of the apparatus containing oxygen (e.g. iron oxide) before contacting the catalyst, and the gases from the hydrogen treatment being prevented from coming into contact with catalyst which has been regenerated (see Group III).  In this way, the formation of water, which would adversely affect the catalyst, is prevented.  Motor fuels and aromatic hydrocarbons are obtained by processes involving hydroforming, platforming, hydrocracking, isomerization, and dealkylation.  Substances treated are crude oil fractions, synthetic gasolines, naphthas, kerosine, and middle oil.  Reaction takes place at 2-30 atmospheres gauge pressure in order to effect dehydrocyclization of alkanes to aromatics. Suitable catalysts are oxides of molybdenum or chromium on alumina, or a platinum group metal on alumina, magnesia-alumina, or silica-magnesia; alumina-containing catalysts may be promoted with chlorine or fluorine.  If sulphur compounds have been present in the feed, treatment with hydrogen is continued until the exit gas is free from hydrogen sulphide.  The invention is also applicable in the dehydrogenation of hydrocarbons, such as butane, and the cyclisation of alkanes.ALSO:In the regeneration of catalysts used in the catalytic treatment of hydrocarbons by periodically burning off carbonaceous deposits followed by treatment with hydrogen, the catalyst is regenerated in situ, the hydrogen is introduced at a place such that it does not come into contact with material of the apparatus containing oxygen (e.g. iron oxide) before contacting the catalyst, and the gases from the hydrogen treatment are prevented from coming into contact with catalyst which has been regenerated. In this way, the formation of water, which would adversely affect the catalyst or the reaction is prevented.  The hydrogen may enter through a line discharging close to or into the middle of the catalyst; if this line is branched, no discharge outlet should be situated downstream of another discharge outlet with respect to the flow of gas through the catalyst.  Part of the hydrogen may flow in a direction away from the catalyst to remove oxygen compounds from the preheating part of the apparatus.  The oxygen-containing gases used for combustion of the carbonaceous deposits may enter close to or into the catalyst, e.g. as described in Specification 744,459; in this case, the walls of the apparatus will not become contaminated with oxygen compounds and the hydrogen may then be introduced further away from the catalyst, e.g. at the point where the hydrocarbons enter later. It is preferred to pass the oxygen-containing gas and the hydrogen through the catalyst in the opposite direction to that of the hydrocarbons and to remove the used gases close to the catalyst. The regenerating gases may be preheated regeneration taking place at about 300 DEG -600 DEG C.  To avoid overheating the oxygen-containing gas has an initial oxygen content of 1 per cent which is increased up to that of air; ozone or nitrogen dioxide may be present in these gases.  The hydrocarbon treatment may be a reforming process to obtain motor fuels and aromatic hydrocarbons and may include hydroforming, platforming, hydrocracking, isomerization, and dealkylation.  Substances treated are crude oil fractions, synthetic gasolines, naphthas, kerosine, and middle oil.  Reaction takes place at 2-30 atmospheres gauge pressure in order to effect dehydrocyclization of alkanes to aromatics.  Suitable catalysts are oxides of molybdenum or chromium on alumina, or a platinum group metal on alumina, magnesia-alumina, or silica-magnesia; alumina-containing catalysts may be promoted with chlorine or fluorine.  If sulphur compounds have been present in the feed, treatment with hydrogen is continued until the exit gas is free from hydrogen sulphide.  A sulphur-free feed may be used or the feed may be desulphurized by treatment with the hydrogen-containing gas from the reforming process at 275 DEG -375 DEG C. in the presence of a platinum catalyst.  The invention is also applicable in the cracking of gasoline, kerosine or middle oil, the dehydrogenation of hydrocarbons such as butane, and the cyclization of alkanes; in these reactions the catalyst may be chromium or molybdenum oxide on a carrier consisting of alumina bauxite, or combinations of alumina with zinc oxide, silica, magnesia, or zirconium oxide.