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What would be the effect of fluctuation in regeneration gas flow in UOP Cyclemax Regenerator if my flow is having variation by 5-8%?? Will there be any effect on catalyst coke burning? What could be the reason for flow variation?
Faridul Qadar, IOCL, firstname.lastname@example.org
All points are nicely covered by Mr Marsh. Regenerator screen plugging is the most obvious cause of reduction in regen gas flow. This has to be corroborated by downward shift in the burn zone peak temperature TI location, i.e. if the peak TI was 2nd from top, then this particular phenomenon would lead to peak temp TI shifting to 3rd TI from top. Thus a loss in burn zone capacity is observed. Please keep an eye on your elutriation gas flow rates and dust removal cycles. You may explore increasing your frequency of dust removal exercise or increasing your elutriation gas flow, however the latter decision may be taken only upon physically checking the condition of the catalyst dust sample from dust collection pot outlet, at least 20%-30% of complete spherical catalyst balls must be ensured in dust sample so that chance of slippage of dust to regenerator tower can be totally negated.
Patrick Bullen, UOP, email@example.com
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Peter Marsh, XBP Refining Consultants Ltd, firstname.lastname@example.org
If the regeneration gas flow is truly fluctuating, you will see this on the amps drawn by the blower motor and in corresponding temperature instability in the burn zone. It is more likely that there is a problem with the flow measurement. The regeneration gas flow is measured via differential pressure across the regeneration gas cooler and the pressure taps are nitrogen purged. Check the nitrogen purge is in commission to the upstream (HP) and downstream (LP) pressure connections and that the purge flows to each are correctly set. If you are operating in a cold climate and/or the thermal insulation around the pressure connections has been damaged or removed you may have chloride salt deposition in the pressure taps.
There will be no impact on available coke burn capacity if the problem is simply a consequence of errors in regeneration gas flow measurement. However, if you are seeing a permanent reduction in regeneration gas flow of 5 - 8%, this will cause a loss of coke burn capacity and you will see a shift in the burn profile and differential pressure across the regeneration gas circuit. The most likely cause for this is plugging of the regenerator screens. If the source of the plugging is not identified and eliminated this will eventually require a shutdown of the Cyclemax Regenerator system for inner/outer screen cleaning.
Ralph Ragsdale, Ragsdale Refining Courses, email@example.com
Maybe a control valve is sticking, has no positioner and needs one. Is the pressure oscillating, too?
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