4 replies to this topic

[suhas]

What is the typical value of Hydrogen content in Coke for Resid FCC operation?

Thanks in advance

[Root]

What is the typical value of Hydrogen content in Coke for Resid FCC operation?

Thanks in advance

Suhas,
Your question is not specific, if you are asking H2 contents in coke, this shold be nil and if you are asking about feed then you check what % of HC you are going to process. Eg C20 to C35 or lesser.

Toor

[suhas]

Dear,
Question is very specific. Coke produced in the FCC is getting burnt in regenerator and that is coke always has some % of Hydrogen in it. There are various sources for this Hydrogen eq poor stripping of spent cat. For conventional FCC this number ranges from 7-8% hydrogen in Coke, I would like to know what is the typical value for Resid FCC.

Thanks in advance
Suhas

What is the typical value of Hydrogen content in Coke for Resid FCC operation?

Thanks in advance

Suhas,
Your question is not specific, if you are asking H2 contents in coke, this shold be nil and if you are asking about feed then you check what % of HC you are going to process. Eg C20 to C35 or lesser.

Toor

[Root]

Dear,
Question is very specific. Coke produced in the FCC is getting burnt in regenerator and that is coke always has some % of Hydrogen in it. There are various sources for this Hydrogen eq poor stripping of spent cat. For conventional FCC this number ranges from 7-8% hydrogen in Coke, I would like to know what is the typical value for Resid FCC.

Thanks in advance
Suhas

What is the typical value of Hydrogen content in Coke for Resid FCC operation?

Thanks in advance

Suhas,
Your question is not specific, if you are asking H2 contents in coke, this shold be nil and if you are asking about feed then you check what % of HC you are going to process. Eg C20 to C35 or lesser.

Toor

Suhas-I have never seen H2 contents in RFCC coke. if you have some information and sources of information better to share on this forum.
Thanks
Toor

[Himanshu Sharma]

FCC heat balance is still one of the most complex areas in cracking reactions.

Refiners often use hydrogen-in-coke as a parameter to judge the performance of their fluid catalytic cracking (FCC) catalyst stripper.

As far as minimum range is concerned and industry accepted average of 5-6 wt% is accepted i.e. catalyst stripper is working the way it was designed to !

For maximum ,In order to define the upper reasonable limit for hydrogen-in-coke, you might consider a case in which a substantial amount of product is burned in the regenerator.

Burning the equivalent of slurry oil (main fractionator bottoms) in the regenerator as coke could be considered an extreme case. In this circumstance, the hydrogen-in-coke would be the nominal hydrogen content of a slurry oil with an atmospheric pressure ionisation (API) of ~01.

So you have a range between 5-6wt% to Hydrogen content of your slurry oil.(roughly around 9-10 wt % depending on type and quantity of residue being processed)

For calculating exactly analyze your flue gas composition and apply the equation provided in "Grace Davidson Guide to fluid cracking part one".(assuming your unit is not running on oxygen enrichment)

After having said this all i must warn you that most often people arrive at wrong conclusion because of Poor Flue Gas analysis