Commissioning of the catalytic cracking unit
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Are there any heavy oil catalytic cracking units that follow a scheme of feeding gasoline components first at the beginning of operation, and then introducing the heavy oil feedstock only after the catalyst has circulated sufficiently and its temperature has risen?
Theoretically it’s possible, but in practice it’s not; doing things this way only slows down the overall process. Tasks that could originally be carried out independently by different colleagues can be combined later, but you insist on handling them one by one – there’s heating during distillation and reactions, waiting for the heavy oil system to switch from open-loop to closed-loop operation, and then heating the raw materials again, among other things
Gasoline feed results in less coking; it mainly absorbs heat, which is not conducive to raising the bed temperature – in fact, it has the opposite effect! I wonder why your factory sprays gasoline first
In fact, in UOP’s catalytic cracking process technology, gasoline is first injected at the bottom of the riser at 315°C to raise the temperature at the outlet of the riser; once the temperature reaches 540°C, the feedstock is then injected. This approach allows for a smoother start-up process, and the operation is relatively simpler. The specific plan should be formulated based on the process of your installation.
To start the compressor without releasing flares, gasoline is sprayed first. That’s what we do as well