| 摘要 |
Alkanes, preferably lower alkanes, are converted to olefins in a 'third bed' external catalyst cooler (ECC) in which hot catalyst from a first regenerator ('second bed') operating in conjunction with a fluid catalytic cracker ('first bed') thermally cracks and dehydrogenates the alkanes. Because this is an endothermic reaction, the catalyst is autogeneously cooled before it is recirculated to the FCC regenerator. The cracking catalyst is the catalyst of choice in the FCC reactor. The conversion of alkanes to olefins is tailored to provide a mixed feed for an aromatization reactor ('fourth bed') which feed is proportioned to provide a substantially heat-balanced reaction in the aromatization reactor, that is, requiring no additional heat other than that which is provided by the feed and the heat of reaction. A second regenerator ('fifth bed') is provided for the aromatization reactor, preferably in a moving bed reactor system. This reactor produces a predominately aromatic hydrocarbon stream. The interrelated operation of this combination of five beds is tailored to convert all available low value alkanes and olefins to produce more valuable benzene, toluene and xylenes in the aromatic stream. |
