Catalyst regeneration method
AssigneeVOP Inc.
InventorsVance P. Burton, Michael Z. Mikulicz
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Abstract
Solid catalysts including solid phosphoric acid catalysts are regenerated in-situ in a multi-step method. A sequence which includes depressurization, soaking in an aromatic hydrocarbon-containing liquid at a high temperature and pressure, depressurization and draining is repeated three times. The regeneration removes polymers formed from olefinic reactants.
Claims4
An in-situ method of regenerating a used fixed-solid phosphoric acid catalyst bed which has been deactivated by agglomerization of polymers formed during polymerization of an olefinic feed stream which comprises the steps of:
- a. terminating the flow of said olefinic stream through said catalyst bed, and then draining any liquid from said catalyst bed while maintaining said catalyst bed at a temperature above 280.degree. F.;
- b. depressurizing said catalyst bed from a pressure above about 300 psig.;
- to a pressure below about 10 psig.;
- c. immersing said catalyst bed drained of said olefinic feed stream in a liquid hydrocarbon mixture containing at least 5 wt. % aromatic hydrocarbon and which has a temperature above 280.degree. F., without a throughput of said hydrocarbon mixture through said catalyst bed and wherein said hydrocarbon mixture is ingressed to said catalyst bed from the bottom of said bed in an upwardly direction;
- d. pressurizing said catalyst bed to a pressure above 100 psig. and soaking said catalyst bed at a temperature over 280.degree. F. for at least 10 minutes while said liquid hydrocarbon mixture is retained within said catalyst bed;
- e. depressurizing said catalyst bed to a pressure below about 10 psig. and draining said liquid hydrocarbon from said catalyst bed;
- f. repeating said steps (c), (d) and (e) twice;
- and,
- g. pressurizing said catalyst bed to the pressure at which said catalyst bed is placed in use.
An in-situ method of regenerating a bed of used fixed-solid phosphoric acid catalyst which has been deactivated by agglomerization of polymers formed during polymerization of an olefinic feed stream which comprises the steps of:
- a. terminating the flow of said olefinic stream through said catalyst bed, and then draining any liquid from said catalyst bed while maintaining the catalyst bed at a temperature above about 325.degree. F.;
- b. depressurizing the catalyst bed from a pressure above 400 psig. to a pressure below about 10 psig;
- c. immersing said catalyst bed drained of said olefinic feed stream in a substantially sulfur-free liquid hydrocarbon mixture containing at least 25 wt. % aromatic hydrocarbons and which has a temperature above about 325.degree. F., without a throughput of said hydrocarbon mixture through said catalyst bed and wherein said hydrocarbon mixture is ingressed to said catalyst bed from the bottom of said bed in an upwardly direction;
- d. pressurizing said catalyst bed to a pressure above about 150 psig. and soaking said catalyst bed in said liquid hydrocarbon mixture at a temperature over about 325.degree. F. for about 60 minutes;
- e. depressurizing said catalyst bed to a pressure below about 10 psig. and draining said liquid hydrocarbon mixture from the catalyst bed;
- f. repeating said steps (c), (d) and (e) twice with a reduced soaking period of about 30 minutes;
- and
- g. pressurizing said catalyst bed to the pressure at which the catalyst bed is placed in operation.
Dependencies are inferred from the claim text.