Conversion of oxygenate to propylene with selective hydrogen treatment of heavy olefin recycle stream
US7405337B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 21, 2004 |
| Grant date | Jul 29, 2008 |
| Priority date | — |
| Expiry date | Jun 29, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P20/584
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The average cycle propylene selectivity of an oxygenate to propylene (OTP) process using one or more fixed or moving beds of a dual-function oxygenate conversion catalyst with recycle of one or more C4+ olefin-rich fractions is substantially enhanced by the use of selective hydrotreating technology on these C4+ olefin-rich recycle streams to substantially eliminate detrimental coke precursors such as dienes and acetylenic hydrocarbons. This hydrotreating step helps hold the build-up of detrimental coke deposits on the catalyst to a level which does not substantially degrade dual-function catalyst activity, oxygenate conversion and propylene selectivity, thereby enabling a substantial improvement in propylene average cycle yield. The propylene average cycle yield improvement enabled by the present invention over that achieved by the prior art using the same or a similar catalyst system but without the use of the hydrotreating step on the C4+ olefin-rich recycle stream is of the order of about 1.5 to 5.5 wt-% or more.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.