英文翻譯(化工)第一部分

Retrofit of an Isobutane Dehydrogenation Facility to make Propylene from Propane(recommended by Gary Sawyer, Lyondell)With the decrease in global demand for MTBE, much of the production capacity has beenidled or put to other uses. One of the routes to MTBE, isobutane dehydrogenation followedby etherification with methanol, has seen a large decrease in capacity in service.Meanwhile, propylene production from steam cracker olefin units cannot keep up with thedemand. This project will investigate the possible retrofit of a butane dehydrogenationplant for propane dehydrogenation to propylene. As such, industry is continuing to bringsignificant amounts of on-purpose propylene production capacity on-stream. You willdetermine the new equipment needed, and the limitations (“bottlenecks”) in existingequipment.A diagram of the process available for retrofit is shown Figure 1. The part of the plant usedto make MTBE from isobutylene is not suitable for use in dehydrogenation. In addition, thecryogenic separation unit previously used to separate and purify hydrogen has been movedto another facility and you are asked to consider a new design for this part of the process.Considerations can include:Cryogenic separationPressure-swing adsorptionTemperature-swing adsorptionMembrane separationsThe reaction is not completely selective to the desired olefin. At the high temperaturesneeded, some side reactions include generation of ethylene, methane, and coke; the latter isa carbon deposit on the catalyst. As the carbon deposits increase, the catalyst is deactivatedand eventually, the reactor is taken off-line, purged, and regenerated with hot air. Theexisting regeneration system is able to regenerate one bed in 8 hours, at a cost of $100,000per regeneration (mostly in utilities).