Severe foulin of turboexpander in FCC unit

[rumirav]

In one of our FCC units (Kellog Orthoflow model), we are suffering severe problems of fouling (fines deposition) in the turboexpander. The scheme of the flue gas circuit is: two stage cyclones in the regenerator + Shell Third Stage Separator before turboexpander + 4th Stage Separator (cyclon) to recover flue gas from fines coming from TSS.
We have also observed high level of moisture in the fines from 4th Stage Separator (10-15%wt). So we suspect that the fouling of the expander is due a cold point in the flue gas circuit (where flue gas humidity is condensed) or an uncontrolled inlet of water / steam.

Has anyone experienced this kind of problems in an FCCU? What could be the potential causes of the severe fouling of the expander?

 

[0707]

you should check your third stage separator ciclones.Have you the possibility to take samples on the bottom of the tss to analyse the catalyst fines?

LM