Methods for chromium catalyst activation using oxygen-enriched fluidization gas
AssigneeChevron Phillips Chemical Company LP
InventorsRalph W Romig, James E. Hein, Troy Bretz, Zhihui Gu
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Abstract
Processes for producing an activated chromium catalyst are disclosed, and these processes comprise contacting a supported chromium catalyst with a gas stream containing from 25-60 vol % oxygen at a peak activation temperature of 550-900° C. to produce the activated chromium catalyst. The linear velocity of the gas stream is 0.18-0.4 ft/sec, and the oxygen linear velocity of the gas stream is 0.05-0.15 ft/sec. The resultant activated chromium catalyst and an optional co-catalyst can be contacted with an olefin monomer and an optional olefin comonomer in a polymerization reactor system under polymerization conditions to produce an olefin polymer.
Claims21
A process to produce an activated chromium catalyst, the process comprising:
- contacting a supported chromium catalyst with a gas stream comprising from 25 to 50 vol % oxygen at a peak activation temperature of from 550° C. to 900° C. to produce the activated chromium catalyst;
- wherein:
- the supported chromium catalyst contains from 0.5 to 2 wt % of chromium, based on a weight of the supported chromium catalyst;
- a linear velocity of the gas stream is in a range from 0.18 to 0.4 ft/sec;
- and
- an oxygen linear velocity of the gas stream is in a range from 0.05 to 0.15 ft/sec.
An olefin polymerization process, the process comprising:
- (i) contacting a supported chromium catalyst with a gas stream comprising from 25 to 50 vol % oxygen at a peak activation temperature of from 550° C. to 900° C. to produce an activated chromium catalyst;
- wherein:
- the supported chromium catalyst contains from 0.5 to 2 wt % of chromium, based on a weight of the supported chromium catalyst;
- a linear velocity of the gas stream is in a range from 0.18 to 0.4 ft/sec;
- and
- an oxygen linear velocity of the gas stream is in a range from 0.05 to 0.15 ft/sec;
- and
- (ii) contacting the activated chromium catalyst and an optional co-catalyst with an olefin monomer and an optional olefin comonomer in a polymerization reactor system under polymerization conditions to produce an olefin polymer.
Dependencies are inferred from the claim text.