Slurry phase polymerisation process
View Patent ↗A process comprising polymerizing in a loop reactor an olefin monomer optionally together with an olefin comonomer in the presence of a polymerization catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent wherein the Froude number is maintained at or below 20 is disclosed.
1. A process comprising polymerizing in as loop reactor an olefin monomer optionally together with an olefin comonomer in the presence of a polymerization catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent wherein the Froude number is maintained at or below 20.
2. A process as claimed in claim 1 wherein the Froude number is in the range 2 to 15.
3. A process a claimed in claim 2 wherein the Froude number is in the range 3 to 10.
4. A process as claimed in claim 1 wherein the solids concentration of the slurry in the loop reactor is in the range 40-60% weight based on the total weight of the slurry.
5. A process as claimed in claim 1 wherein the solids concentration of the slurry in the loop reactor is in the range 25-35% by volume.
6. A process as claimed in claim 1 wherein the loop reactor has an internal diameter of over 500 millimeters.
7. A process as claimed in claim 6 wherein the internal diameter is in the range 600 to 750 millimeters.
8. A process as claimed in claim 1 wherein total pressure drop in the loop reactor is less than 1.3 bar.
9. A process as claimed in claim 1 wherein the reactor size is greater than 50 m 3 .
10. A process as claimed in claim 9 wherein the reactor size is in the range 75-150m 3 .
11. A process as claimed in claim 1 wherein the reactor length to internal diameter ratio is less than 400.
12. A process as claimed in claim 11 wherein the ratio is less than 250.
13. A process as claimed in claim 1 wherein the space time yield is in the range 0.2-0.35 ton/hour/m 3 .
14. A process as claimed in claim 1 wherein the olefin is ethylene.
15. A process as claimed in claim 14 wherein the comonomer is at least one of butene-1, pentene-1, or hexene-1.
16. A process as claimed in claim 14 wherein the diluent is isobutane.
17. A process as claimed in claim 1 wherein the olefin is propylene.
18. A process as claimed in claim 1 wherein the particulate polymer is withdrawn from the reactor in a continuous fashion.
19. A process as claimed in claim 1 wherein the catalyst is selected from the group consisting of Ziegler catalysts, inorganic supported chromium oxide catalysts and metallocene catalysts.
20. A process as claimed in claim 1 wherein the loop reactor is one of two or more loop reactors connected in series.