Preparation of high octane alkylate from Fischer-Tropsch olefins
AssigneeChevron U.S.A. Inc.
InventorsDennis J. O' Rear, Steven S. Mathur, Thomas Van Harris, Curtis L. Munson, Cong-Yan Chen
Life of this patent
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Abstract
A Fischer-Tropsch C3-C4 olefin stream is treated to lower the oxygenate content to below 4000 ppm. Another Fischer-Tropsch fraction is hydrotreated and hydrocracked to provide an isobutane-containing stream. The treated C3-C4 olefin stream is reacted with the isobutane stream in an alkylation reactor to provide a highly branched, high octane isoparaffinic alkylate. The alkylate is useful as a blending component in motor gasoline.
Claims16
A process for manufacturing a high octane alkylate comprising the steps of:
- (a) obtaining a C3-C4 light olefin fraction from a Fischer-Tropsch reactor;
- (b) treating the olefin fraction to reduce the oxygenate level to below about 4000 ppm;
- (c) mixing the olefin fraction with an isoparaffin stream obtained from a Fischer-Tropsch reaction containing at least 30 wt. % isobutane;
- (d) reacting the combined stream from step (c) in the presence of an alkylation catalyst;
- and
- (e) 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 fraction containing propylene, 1-butene, and alcohols;
- a C5 to 300° F. naphtha fraction containing alcohols;
- 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) removing at least a portion of the alcohols from the light olefin fraction;
- (e) optionally, treating the 1-butene in the light olefin fraction with an isomerization catalyst;
- (f) admixing the isobutane-containing fraction from step (c) with the light olefin fraction from step (d);
- (g) reacting the admixture from step (e) in the presence of a liquid phase alkylation catalyst;
- and
- (h) recovering said alkylate.
A olefin feed for an alkylation plant, the feed comprising C3 and C4 olefins, having less than 1000 ppm oxygenates, and less than 10 wt % of isobutene as a percentage of the C4 olefins.
Dependencies are inferred from the claim text.