3 replies to this topic

[jigs1980]

Where should we add CO promoter in two stage regenerator? Either in regenerator - I or in Regenerator - II? RG-I is having partial combution operation and RG-II is having total combution operation.
Coke after partial combustion in RG-I is shifted to RG-II for total combustion.
So where should we add CO promoter and what is the reason/advantage for it?
Thanx

[kkala]

I am not aware of the subject at all, but web gives the impression it concerns catalyst regeneration in catalytic cracking units, where burning of CO to CO2 should be promoted to avoid coke.
By googling "carbon monoxite copromoter" you can find some info in Web, e.g. http://www.springerl...10500214102p0w/. At an ignorant's look (thinking of CO promoter to both regeneration stages) this web reference is not quite clear concerning your query, but it could help. Technology seems not to be new, hopefully some member having real experience can offer advice, and so can the supplier of the promoter.

Note: By googling "CO promoter" you can obtain BASF http://www.refiningo...ean_BF7891.pdf , useful only as general info.

Edited by kkala, 01 September 2011 - 01:48 AM.

[saeed.s]

Hi
One of problem in Heavy feed catalytic cracking is high level of coke on catalyst that also release a lot of heat in re-generator. To compete this , Licensors use two ways :
1- catalyst cooler in re-generator ( with producing steam)
2-Two stage re-generator , first stage works in partial combustion mode , (Convert about 70-80% of cock to CO that have lower heat compared with CO2) and second stage works in total combustion mode ( Convert remained coke to co2)
In re-generator exist two phase : 1- dense phase catalyst 2-dilute phase and it s important combustion occur in dense phase because without catalyst bed to absorb heat of combustion, temperature of dilute phase and flue gas increase rapidly( the name of this phenomenon is after burn) . Using co promoter leads to co reaction( convert to co2 ) occurs in dense phase . Therefor using co-promoter in 2nd stage has better result.

Edited by behnam, 16 November 2011 - 04:05 PM.

[kkala]

Thanks for the info. It is assumed that in stage II regenerator (fluidised bed of catalyst particles) both dense and dilute phase exist, with combustion gases passing first from dense phase and then from dilute phase.