BTX from naphtha without extraction
AssigneeUop LLC
InventorsChristopher D. Gosling, Robert S. Haizmann
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Abstract
A hydrocarbon feedstock is catalytically reformed in a sequence comprising a reforming zone containing a catalyst comprising a platinum-group metal and a nonacidic L-zeolite and an aromatics-isomerization zone containing a catalyst comprising a platinum-group metal, a metal attenuator and a refractory inorganic oxide. The process combination features high selectivity in producing a high-purity BTX product from naphtha.
Claims18
A process combination for the upgrading of a hydrocarbon feedstock to a substantially pure BTX (benzene, toluene and xylenes) product consisting essentially of the steps within the same hydrogen circuit of:
- (a) contacting a hydrocarbon feedstock containing paraffins and naphthenes in the presence of free hydrogen in a reforming zone at reforming conditions including a temperature in the range of from 260.degree. to 560.degree. C. with a reforming catalyst comprising a nonacidic large-pore zeolite having a pore size of at least 6 .ANG., a refractory inorganic oxide and a platinum-group metal component to produce an aromatics-enriched effluent;
- and
- (b) contacting the aromatics-enriched effluent without extraction of aromatics therefrom in an aromatics-isomerization zone at aromatics-isomerization conditions including a temperature in the range of 100.degree. to 600.degree. C. with an aromatics-isomerization catalyst comprising a medium-pore molecular sieve having a pore size of from 5 to 6.5 .ANG., a refractory inorganic oxide, a platinum-group metal component and a lead or bismuth metal attentuator to obtain a concentrated BTX product wherein a xylene concentrate contains no more than about 5 mass % ethylbenzene.
A process combination for the upgrading of a hydrocarbon feedstock within a single hydrogen circuit to a pure BTX (benzene, toluene and xylenes) product consisting essentially of the steps within the same hydrogen circuit of:
- (a) contacting a hydrocarbon feedstock containing paraffins and naphthenes in the presence of free hydrogen in a reforming zone at reforming conditions including a temperature of from 260.degree. to 560.degree. C. with a reforming catalyst comprising a nonacidic large-pore zeolite having a pore size of at least 6 .ANG., an alkali-metal component and a platinum-group metal component to produce an aromatics-enriched effluent;
- and,
- (b) contacting the aromatics-enriched effluent without extraction of aromatics therefrom in an aromatics-isomerization zone at aromatics-isomerization conditions with aromatics-isomerization catalyst comprising a platinum-group metal component, a lead or bismuth metal attentuator and a refractory inorganic oxide to obtain a concentrated BTX product wherein a xylene concentrate contains no more than about 5 mass % ethylbenzene.
A process combination for the upgrading of a hydrocarbon feedstock within a single hydrogen circuit to a pure BTX (benzene, toluene and xylenes) product consisting essentially of the steps within the same hydrogen circuit of:
- (a) contacting the hydrocarbon feedstock in the presence of free hydrogen in a reforming zone at reforming conditions including a temperature of from 260.degree. to 560.degree. C. with a reforming catalyst comprising a nonacidic large-pore zeolite having a pore size of at least 6 .ANG., an alkali-metal component and a platinum-group metal component to produce an aromatics-enriched effluent;
- (b) contacting the aromatics-enriched effluent without extraction of aromatics therefrom in an aromatics-isomerization zone at aromatics-isomerization conditions including a temperature of from 100.degree. to 600.degree. C. with an aromatics-isomerization catalyst comprising a platinum-group metal component, a lead or bismuth metal attentuator and a refractory inorganic oxide to obtain a concentrated BTX product;
- (c) fractionating the BTX product to obtain benzene, toluene and xylene concentrates;
- and,
- (d) separating the xylene concentrate containing no more than about 5 mass % ethylbenzene in a para-xylene separation zone to obtain para-xylene and a para-xylene-depleted raffinate, and recycling the raffinate to the aromatics-isomerization zone.
Dependencies are inferred from the claim text.