Manufacture of high octane alkylate
AssigneeChevron U.S.A. Inc.
InventorsDennis J. O'Rear, Steven S. Mathur, Thomas Van Harris, Curtis L. Munson, Cong-Yan Chan
Life of this patent
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Abstract
A Fischer-Tropsch C3-C4 olefin stream is simultaneously dehydrated and isomerized to convert alcohols to olefins and 1-butenes to 2-butenes and thereby lower the oxygenate content. Another Fischer-Tropsch fraction is hydrotreated and hydrocracked to provide an isobutane stream. The treated C3-C4 olefin stream having an oxygenate content less than 4000 ppm, is reacted with the isobutane stream to provide a highly branched, high octane isoparaffinic alkylate. The alkylate is useful as a blending component in motor gasoline.
Claims20
A process for manufacturing a high octane alkylate comprising the steps of:
- (a) obtaining a C3-C4 light olefin fraction from a Fischer-Tropsch reaction;
- (b) treating the olefin fraction with a dehydration/isomerization catalyst which converts alkanols to olefins and isomerizes the C4 olefin portion of the fraction;
- (c) optionally treating the olefin fraction from step (b) to reduce the oxygenate level to no more than about 4000 ppm;
- (d) mixing the treated olefin fraction with an isoparaffin stream comprising isobutane;
- (e) reacting the combined stream from step (d) in the presence of an alkylation catalyst;
- and
- (f) recovering a highly branched isoparaffinic alkylate having a research octane number of at least about 80.
A process of manufacturing an alkylate which is highly branched, has a high isoparaffin content and has an octane number of at least about 80, comprising:
- (a) reacting a mixture containing CO and H2 in the presence of a Fischer-Tropsch catalyst;
- (b) recovering a mixture of hydrocarbonaceous products including a light olefin C3-C4 fraction containing propylene, butylene, alkanols and organic acids;
- a C5 to 300° F. naphtha fraction;
- and a 300° F.+ fraction;
- (c) subjecting the 300° F.+ fraction to hydrotreating, hydrocracking, hydrodewaxing or combinations thereof and recovering a fraction containing at least about 30 wt. % isobutane;
- (d) contacting the light olefin C3-C4 fraction with a catalyst which dehydrates alkanols to alkenes and isomerizes 1-butene to 2-butene;
- (e) subjecting the dehydrated/isomerized C3-C4 olefin fraction from step (d) to a water washing, decarboxylation, distillation, adsorption or combination thereof to reduce the oxygenate content to less than 4000 ppm;
- (f) admixing the isobutane-containing fraction from step (c) with the C3-C4 olefin fraction from step (e);
- (g) reacting the admixture from step (f) in the presence of a liquid phase alkylation catalyst;
- and
- (h) recovering said alkylate.
Dependencies are inferred from the claim text.