We dug this out of the archives for all you cat cracking enthusiasts. This is the flow diagram for the original Exxon Model 1 design. The first Model 1 unit was started up in Baton Rouge (Exxon) in May, 1942. It was called PCLA No. 1 (Powdered Catalyst, Louisiana). In fact, that naming convention still stuck around for those of you familiar with that and other Exxon plants.
Often I get asked by friends and family who are of the diesel car or truck persuasion, why is diesel so much more expensive than gasoline? Then next question is inevitably, why don’t the refineries make more diesel? My typical response is, “trust me, they are trying to make all the diesel they can. But it is not that easy to retool the plant.” FCCs are gasoline molecule making machines. If you couple that with an alkylation unit, the plant can upgrade heavier molecules into a large percentage gasoline. But not that much diesel results as a side product. There have been many advances to catalyst and reactor internals to alter this relationship but the changeover is slow and limited. More diesel is on the horizon as additional hydrocracking capacity comes online and with the non-conventional feedstocks booming in North America at the moment.
Let’s put this out for discussion: How many differences between your “modern” FCC and the Model 1 can you spot?
Bonus question: Where (and when) was the first successful FIXED BED catalytic cracker started up?
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