FCCU catalyst damage

[Hedewandro Lucredi]

Our FCCU stopped because we had a utilities emergency. During the shutdown emergency we had a equipment failure at gas compressor. During the gas compressor maintenance we intend to keep the catalyst circulation by keeping the torch oil injection, probably during 2 weeks. What about the catalyst activity because we are injecting torch oil? I am concerned about some damage in the catalyst activity during torch oil injection. Surface are reduction ? Is the damage high ?

[Christopher Dean]

Keeping the FCC unit on hot standby, holding the catalyst inventory in the regenerator and keeping it “hot” with torch oil is usually done for short outages when a quick unit repair can be conducted. Catalyst circulation to keep the converter section hot can be maintained only for a brief period of time. Normally these warm/hot standbys are only done for a couple of days as a maximum.

Catalyst damage as you mention from loss of activity, loss of surface area will occur. Over longer periods of using torch oil the catalyst will tend to sinter resulting in higher density from loss of pore volume and surface area. This may lead to circulation issues.

Usually if a unit needs to be down for several days, unfortunately, a complete shutdown of the converter, emptying the unit inventory to the ecat hopper, etc. is required.

I would also suggest that you contact your catalyst supplier for their guidance and assistance in your current unit situation.

I hope my comments help.

Christopher Dean Refining Community – High Olefins FCC Technology Services

[Hedewandro Lucredi]

Thanks. It is very helpful

[dblewis]

I agree with Chris about the catalyst damage. In our situation, we would rather tear up the catalyst than shut down and de-inventory. Our air line burner is not reliable enough to hope it will perform properly for startup without actually pulling it and performing maintenance on it. Generally during a utility outage, catalyst would back up to the check valve of the Main Air Blower and wreak havoc on the air line burner as it was not designed to see Regenerator catalyst. We also have 2 1st stage compressors and a 2nd stage compressor which also plays into our decision to keep the Regenerator, Reactor, & Main Fractionator hot. We have kept our Regenerator hot for a week or so with obvious catalyst damage but rather easy to re-start the unit.

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