US 5,401,388 AGranted

Selective upgrading of naphtha

AssigneeUop LLC

InventorsRobert J. Schmidt, Michael B. Russ, Paula L. Bogdan, R. Joe Lawson, Norman L. Gilsdorf

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Abstract

A process combination is disclosed to selectively upgrade naphtha to obtain gasoline which is in accordance with current standards for reformulated fuels. A naphtha feedstock is fractionated to selectively direct light naphtha to isomerization or blending, a head-cut fraction to reforming, and a heavy potion to selective isoparaffin synthesis to yield light and heavy synthesis naphtha and isobutane. The heavy potion of the synthesis naphtha is processed by reforming. Light naphtha may be isomerized, with or without recycle of low-octane components of the product. A gasoline component is blended from light, synthesis, and reformate products from the process combination.

Claims23

Dependent claims

A process combination for selectively upgrading a naphtha feedstock to obtain gasoline of enhanced octane number comprising the steps of:

(a) separating a naphtha feedstock to obtain a heart-cut naphtha fraction comprising C.sub.7 and C.sub.8 hydrocarbons and a heavy naphtha fraction comprising C.sub.10 hydrocarbons;
(b) contacting the heart-cut naphtha fraction with a reforming catalyst, comprising a supported platinum-group metal component, in a catalytic-reforming zone maintained at reforming conditions comprising a pressure of from about atmospheric to 20 atmospheres absolute, a molar hydrogen-to-hydrocarbon ratio of from about 0.1 to 10, a liquid hourly space velocity of from about 1 to 40 hr.sup.-1, and a temperature of from 260.degree. to 560.degree. C. and recovering a stabilized reformate;
and,
(c) contacting the heavy naphtha fraction with a solid acid selective isoparaffin-synthesis catalyst comprising a zeolite in a selective-isoparaffin-synthesis zone maintained at selective-isoparaffin-synthesis conditions comprising a pressure of from about 10 atmospheres to 100 atmospheres gauge, a molar hydrogen-to-hydrocarbon ratio of from about 0.1 to 10, a liquid hourly space velocity of between about 0.5 to 20 hr.sup.-1, and a temperature of from 50.degree. to 350.degree. C. and recovering synthesis effluent having a reduced end point relative to the heavy naphtha fraction and containing butanes and pentanes.

1 more element

A process combination for selectively upgrading a naphtha feedstock to obtain gasoline of enhanced octane number comprising the steps of:

(a) separating a naphtha feedstock to obtain a light naphtha fraction comprising pentanes, a heart-cut naphtha fraction comprising C.sub.7 and C.sub.8 hydrocarbons and a heavy naphtha fraction comprising C.sub.10 hydrocarbons;
(b) contacting the heart-cut naphtha and a heavy synthesis naphtha with a reforming catalyst, comprising a supported platinum-group metal component and a nonacidic L-zeolite, in a catalytic-reforming zone maintained at reforming conditions comprising a pressure of from about atmospheric to 20 atmospheres absolute, a molar hydrogen-to-hydrocarbon ratio of from about 0.1 to 10, a liquid hourly space velocity of from about 1 to 40 hr.sup.-1, and a temperature of from 260.degree. to 560.degree. C. and recovering a stabilized reformate;
and,
(c) contacting the heavy naphtha fraction with a solid acid selective isoparaffin-synthesis catalyst in an selective-isoparaffin-synthesis zone maintained at selective-isoparaffin-synthesis conditions comprising a pressure of from about 10 atmospheres to 100 atmospheres gauge, a molar hydrogen-to-hydrocarbon ratio of from about 0.1 to 10, a liquid hourly space velocity of between about 0.5 to 20 hr.sup.-1, and a temperature of from 50.degree. to 450.degree. C. in the presence of hydrogen, recovering synthesis effluent containing butanes and pentanes, and separating the synthesis effluent to obtain an isobutane concentrate, a light synthesis naphtha comprising pentanes and heavy synthesis effluent comprising C.sub.7 and C.sub.8 hydrocarbons;
(d) contacting the heavy synthesis effluent with a reforming catalyst, comprising a supported platinum-group metal component and a nonacidic L-zeolite, in a catalytic-reforming zone maintained at reforming conditions comprising a pressure of from about atmospheric to 20 atmospheres absolute, a molar hydrogen-to-hydrocarbon ratio of from about 0.1 to 10, a liquid hourly space velocity of from about 1 to 40 hr.sup.-1, and a temperature of from 260.degree. to 560.degree. C. and recovering a reformed synthesis product as a stabilized reformate;
and
(e) blending the gasoline comprising at least a portion of each of the light naphtha, light synthesis naphtha and stabilized reformate.

4 more elements

Dependencies are inferred from the claim text.