| 摘要 |
The average propylene cycle yield of an oxygenate to propylene (OTP) process using a dual-function oxygenate conversion catalyst is substantially enhanced by the use of a combination of: 1) moving bed reactor technology in the catalytic OTP reaction step in lieu of the fixed bed technology of the prior art; 2) a separate heavy olefin interconversion step using moving bed technology and operating at an inlet temperature at least 15° C. higher than the maximum temperature utilized in the OTP reaction step; 3) C<SUB>2 </SUB>olefin recycle to the OTP reaction step; and 4) a catalyst on-stream cycle time of 700 hours or less. These provisions hold the build-up of coke deposits on the catalyst to a level which does not substantially degrade dual-function catalyst activity, oxygenate conversion and propylene selectivity, thereby enabling maintenance of average propylene cycle yield for each cycle near or at essentially start-of-cycle levels.
|
