How to reduce coke fines for DCU which produce sponge coke?

[Paul R OrlowskiKeymaster]

Submitted by Kun-Chuo Chen
Refinery Operation and Optimization
How to reduce coke fines for DCU which produce sponge coke?

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Francisco Fernández
Lead Process Engineer at PDVSA INTEVEP
The first thing I’d say is: Cut your drum faster. Taking too much time to cut a drum means using much more water, and it can increase dramatically the amount of coke fines generated, especially if producing sponge coke. Of course cutting a drum too fast has its drawbacks, but if you can reduce the time from 4 to 3 or 2 hrs, for example by recovering the cutting pressure you lost by that leaking isolation valve you will generate less coke fines.

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Micahel Gil Franceschi
Field Operator / Boardman PDVSA
my opinion is increase COT if yours chard is very light

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Claus Graf
Sr. Mechanical / Rotating Equipment Engineer, Airswift
Cut the drum faster.

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Kun-Chuo Chen
The coke handling system in our DCU is a slurry system(without open pit). We can not cut coke too faster and raise COT too much. This system is good for environment, but is not good for operation efficiency.

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Alexis. Lira.
MSc Chemical Engineer, PDVSA
Well I do not absolutely agree about to increase the COT, because a harder coke could produce more fines. According to the theory a harder material like a diamond can not absorb the impacts as result it is too fragil and breaks. That could happen is you increase the COT, produce a harder coke but softer and you would produce more fines, maybe if you looking deep you will realize that you fines production it is not in the cut step and maybe during the next step when you reduce big coke blocks to be transported to the storage place. In case that effectively the fines productions be during the drum cut, you could check how is your VCM in the coke, high VCM could produce too much soft coke and during moving in the handling system the coke breaks and become smaller and smaller whatever your handling system be, open or close pit.

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Francisco Fernández
Mr. Chen, when you say the coke handling system is a slurry system, do you mean coke transportation through pipelines? Because that could be increasing the amount of coke fines. I’m currently working on a project to install one of those systems, and we’re concerned about the generation of coke fines in the transportation process. In fact, if you have more information about that kind of system I would be grateful if you can share it. Is the coke being sent directly to an end user (power generation for example) or it is being sold?

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Kun-Chuo Chen
Kun-Chuo Chen The cutting coke from coke drum fell down to a crusher and sluce way, it then enter a small pit. A slurry pump then send the coke slurry to a dewater bin. We export all the pet coke in this refinery. We process high sulfur crude from Mid-East.

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Emiro Jose Guignan Campos
Process Engineer en PDVSA Petroleos de Venezuela S.A./ Daewoo E/C Seul
Maintain a 11-13 % VCM

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ted pivovarnik (aka. PIVO)
maintenance supervisor cokers/ retired
Do you not have a holding area for the water to DRAIN from the coke before it is moved to the Crusher. Is the coker transferred by front end loaders or overhead cranes? Water cyclones do remove some fines but not enough.

In addition, anything you can do to make your coke harder or less soft (increasing COT or reducing recycle) will also help.

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