How to minimize FCC catalyst escape while conveying?

[yoze]

Dear all
At our FCCU we use two silos - one for the fresh catalyst and one for the eCat (i.e. the spent catalyst).
In order to convey the fresh catalyst from the supllier's container to one silo and in order to unload the eCat from the regenerator to the other, we apply vacuum to the silos using a steam ejector (directed to the atmosphere)
However, this routinley operation is accompanied by the escape of catalyst to the open air.
Does anyone have an experience with this kind of operation and are there any better techniques?
Does anyone that uses the same technique has a recommendation for a filtering method?
Thanks, Yoze

 

[darwish53]

Better to check the ejector steam strainer and clean it may be chocked normally to keep the fresh cat. hopper under vac. press around -.95kg/cm2 . i think the catalyst loosing while loading or with drawl due to vac. problem -
thanks