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What are the reasons for a drop in DP of a spent catalyst slide valve in a FCCU?
 
Answers
06/05/2020 A: Nishant Kumar, Indian Oil Corporation Limited, kumarn20@indianoil.in
Sometimes improper aeration at the downstream side of the SCSV causes the defluidization of spent catalyst to some extent, especially if a long spent catalyst standpipe is used in your plant design. One should check the aeration air taps and air flow rate through them. a single pressure gauge survey provides insights into the pressure balance of the unit and helps in establishing a pressure and density profile in the reactor-regenerator section which is essential to diagnose and troubleshoot such problems.
08/04/2020 A: ABHISHEK SHARMA, Production, abhisharma3143@gmail.com
There can be two reasons for a drop in dp across the spent catalyst slide valve
1. Erosion in the bottom part of the valve due to catalyst movement
2. Refractory damaged and trapped in the catalyst exit towards regeneration.
So many incidents happen due to malfunction of this valve, hydrocarbon entering the regeneration system, and explosion occurring.
08/04/2020 A: ABHISHEK SHARMA, Production, abhisharma3143@gmail.com
There are so many incidents happen in FCC plants due to DP drop across the slide wall because air and hydrocarbon will mix and explosion will occur.
This is due to erosion caused by the continual flow of catalyst continually; another reason is refractory damage near the entry to the regenerator.
26/03/2020 A: Manan Joshi, L&T-Chiyoda, joshimanan01@gmail.com
In most cases there is lot more erosion in this valves. If you are trying to control the solid flow through this valves as due to erosion the flow coefficient has changed you are closing more then required. This may cause higher pressure drop. Am not sure but can you share the vendor's name and valve size, I can give more details.