Re: Petcoke´S Pneumatic Transport Problems
Dear Emiliano,
The first thing that comes to my mind is: I what aspects does the domestic petcoke differ from the other types of petcoke? Particle size, stickiness?
It seems that the pneumatic conveying installation is designed for a certain type of petcoke and not for this type of petcoke.
Assuming the installation (compressor) is in good condition.
The phenomenon, which you describe, could be caused by a too low air velocity in relation to the suspension velocity.
For the calculation of the required air velocity, it is necessary to know the pipe size, pipe length vertical, pipe length horizontal, number of bends, air compressor displacement, capacity, altitude, temperature, particle size (distribution), particle density and bulk density.
Is the amount of conveying air dictated by the amount of combustion air?
Have a nice day
Teus ■
Teus
Pet Coke
It sounds as if you have too do some pipe cleaning in the delivery system as the presure builds up and these releases OR the local coke may be larger in size ■
Re: Petcoke´S Pneumatic Transport Problems
Pet coke injection in cement kiln is very standard. Normally pulverised pet coke is used in cement kilns. Convening air %age is small as compared to the total air fed into the kiln the main induction fans are capable of changing air flows to accommodate some variations. End velocities are always kept above 28 m/s to avoid blow backs. Normally high wear is the problem with these kind of systems.
What you are describing is not build up in bends it is pulsations in the system this causes CO peaks and all the associated problems. Very common for badly designed injection systems where the feed is not smooth. This will be more prominent at the lower end of the feed rate. But since your system works fine with other grades I will check the flow properties of Argentinian pet coke and its suitability for existing hopper. It seams it is not flowing in hoppers properly and you are getting dollops of material . Are both cokes coming from same mill ?Also check moisture content of both cokes and you might get the answer there. ■
Re: Petcoke´S Pneumatic Transport Problems
Responding to questions:
* There are two burners in the kiln and in either case the same problem.
* The compressors are operating properly.
* To determine that the problem was the domestic petcoke were tested several mixtures made with coal and petcoke (including petcoke in the Caribbean with which there are no problems).
* It was established that the presence of 30% of domestic petcoke, the trouble begins.
* There are no moisture values above 1.5% at the national petocke but after grinding the petcoke is very pasty
* The national petcoke comes from two different points and with both the problem occurs.
* Is the amount of air conveying dictate by the amount of combustion air? Is NOT
* The milling conditions are: Retained mesh 90 between 3 and 4% humidity between 1.3 and 1.9%. There is only a mill for grinding.
I appreciate the answers given by Teu, lzaharis and Mantoo.
Any other suggestions or questions will be grateful.
Thank you very much. ■
Re: Petcoke´S Pneumatic Transport Problems
Dear Emiliano,
Your observation that the national petcoke is very pasty is probably the cause of your problem.
The ground petcoke will form agglomerations, bigger than the grinded size.
These agglomerations have a higher suspension velocity and therefore require a higher air velocity.
As the amount of conveying air is not dictated by the amount of combustion air, you are free to inject more air into the conveying line. (May be you have to reduce the secondary combustion air)
For a simple test, you can try to inject extra air with a normal plant air compressor with a pressure reducer to protect the installation against over pressure.
How much air can only be determined in relation to the existing installation.
(See my previous reply)
Have a nice ay
Teus ■
Teus
Re: Petcoke´S Pneumatic Transport Problems
Dear Teus:
We know that the pasty material is causing the problem. We believe that the pasty material is a problem caused by the method of extraction in the oil refineries or cracking processes.
I wanted to share this problem to see if somewhere else have this problem and how to avoid it.
I greatly appreciate your answers.
Have a nice day too! ■
Re: Petcoke´S Pneumatic Transport Problems
I think that before coming to a definite conclusion you should check the material's flow properties by running a home made test to find out if this material is really pasty.
Pasty materials will not flow freely from storage bins and hoppers. If you are not having this flow problem, you may have some other reason for conveying line plugging.
Regards,
Amrit Agarwal
Consulting Engineer
Pneumatic Conveying Consulting
Charleston, WV, USA
Email: polypcc@aol.com ■
Petcoke´s Pneumatic Transport Problems
Hi all
I'm a process engineer at a cement plant in Argentina, called Loma Negra - L'Amalia - and we are having problems with the transport of petcoke to the burners. The same remains stuck in the pipes, especially at the elbows. Evidence of this is a small increase in pressure in the air transport, the material being stalled for 10 seconds and then released with greater pressure on the tip of the burner, causing an increase in carbon monoxide and consistent stop clinker kiln for safety interlock.
So far we have noticed this problem only with the domestic petcoke (Argentina).
I would like to share this information, to know whether there are other similar cases and to hear suggestions about it.
If someone wanted to know more deeply the issue, please ask.
Sorry about my English
Greetings. ■