Butene-2
| 원료 | Propylene |
| 생산물 | butene-2 |
| 적용 | To produce high-purity butylene (mostly butene-2) and ethylene from propylene using the Triolefin process. |
| 설명 | Description:
The Triolefin process uses a disproportionation reaction whereby relatively low-cost propylene can be upgraded to more valuable ethylene and butylenes. For every two moles of propylene converted, approximately one mole of ethylene and one mole of butylene are produced. The reactor (1) operation is cyclic, and carbon is burned off periodically with air mixed with an inert diluent. Propylene conversion per pass is approximately 40%. Unconverted propylene is recycled (2) back to the reactors. Any ratio of propane-propylene is permissible in the unit feed although the internal recycle stream becomes larger as the propane content is increased. A small percent of the propylene that is converted forms pentenes and heavier material. No more than trace quantities of methane, ethane, isobutylene and butanes are produced in the disproportionation reactors. Ethylene suitable for polyethylene production can be fractionated (3) easily from the C3 and heavier product from the reactor provided that the feed to the Triolefin process unit has previously been deethanized. If a high-purity butylene product is desired, the reactor feed can be debutanized, leaving nearly pure C3s, and an additional purifiction column (4) can be added to the Triolefin process unit to remove C5s and heavier. High-purity product can be produced in this way by relatively inexpensive fractionation rather than by difficult ethylene-ethane and butane-butene-2 separations. Usually more than 90% of the butylene from the reactors is butene-2, an excellent feedstock for alkylation to produce high octane motor fuel. Since only trace quantities of C4s other than normal butylenes are present. Triolefin process butylenes are a highly desirable feedstock for isomerization to butene-1 monomer. Reactor onstream cycle times can be extended by reduction of the acetykene and diolefin content of the feed. This can be done easily by selective hydrogenation over a catalyst containing palladium. Catalysts for this purpose are available from well-known catalyst suppliers. It is also necessary for the feed to be dry and free of sulfur for satisfactory operation. Operation conditions: The reactors can be operated at from 0 to 500 psig without affecting reaction a great deal. The WHSV is practical in the range of 10 to well over 100. Yields: The conversion of propylene to ethylene and butylene is normally over 95%. |
