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US 7,067,597 B2Granted
Process of making polypropylene from intermediate grade propylene
AssigneeExxonMobil Chemical Patents Inc.
InventorsCor F. Van Egmond, Lawrence C. Smith
Life of this patent
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Abstract
This invention concerns using an intermediate grade propylene stream as feed to a polypropylene forming reaction system. The intermediate grade propylene stream is preferably recovered form the olefin product of an oxygenate to olefins reaction process, and low in dimethyl ether content.
Claims19
A process for making polypropylene, comprising the steps of:
- a) separating a propylene stream and a dimethyl ether stream from an olefin stream, with the propylene stream being separated as an overhead distillation stream and the dimethyl ether stream being separated as a bottoms distillation stream;
- b) recovering an intermediate grade propylene stream from the overhead stream, wherein the intermediate grade propylene stream contains less than 99.5 wt % and at least 95 wt % propylene;
- c) contacting the intermediate grade propylene stream with polypropylene forming catalyst to form polypropylene and unreacted by-product;
- d) recovering propylene from the unreacted by-product to form a recycle stream;
- and
- e) contacting the recycle stream with the polypropylene forming catalyst to form additional polypropylene product.
3 more elements
A process for making polypropylene product, comprising the steps of:
- a) contacting an oxygenate stream with an olefin forming catalyst to form on olefin stream, wherein the olefin stream comprises propylene, propane and dimethyl ether;
- b) separating the propylene, propane and dimethyl ether from the olefin stream to obtain an intermediate grade propylene stream, wherein the intermediate grade propylene stream contains less than 99.5 wt % and at least 95 wt % propylene;
- c) contacting the intermediate grade propylene stream with a polypropylene forming catalyst to form a polypropylene product.
A process for making polypropylene product, comprising the steps of:
- a) contacting an oxygenate stream with an olefin forming catalyst to form an olefin stream;
- b) separating a propylene stream from the olefin stream;
- c) sending the propylene stream to a propylene separation system;
- d) recovering an intermediate grade propylene stream from the propylene separation system, wherein the intermediate grade propylene stream contains less than 99.5 wt % and at least 95 wt % propylene;
- c) contacting the intermediate grade propylene stream with a polypropylene forming catalyst to form a polypropylene product and unreacted propylene;
- and
- f) removing at least a portion of the unreacted propylene in the propylene separation system, wherein the intermediate grade propylene stream further comprises the removed portion of unreacted propylene.
4 more elements
Dependencies are inferred from the claim text.