Q & A > Question Details
Can we change the trash baskets in heavy naphtha hydrotreater reactor by ceramic balls?
(in all turnarounds trash baskets are clean without any scales but assembly of 85 baskets is very hard!!!)
catalyst volume is 30 cubic meter
 
Answers
18/06/2014 A: rvidner chib, RIl, rschib@rediff.com
Just put some CAT TRAP material cat trap 65/80 to take care of rust issues. Other grading material may not be useful. These are for trapping iron scale. A STRICT NO TO CERAMICS.
Clean Trash baskets could also mean iron naphthenates which no trash basket can catch.
Put Cat trap and sleep well..
05/10/2013 A: Virendra Kapoor, Petroleum Refining Consultants, vkkapoor9@yahoo.com
I highly appreciate the reply posted by Mr. Kamaljit from Digboi. He has presented very good experience It is tough job to place and remove the baskets during maintenance and other activities.
However there are vendors who supply very good active alumina balls of proper surface areas and grading materials which are equally or superior to performance with respect to baskets. Their selection is the key
02/10/2013 A: Alan Goelzer, Jacobs Consultancy, alan.goelzer@jacobs.com
As Ralph Ragsdale indicated, the answer is yes. However, I recommend using sequence of top dressing shapes instead of alumina balls.
01/10/2013 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
Yes. You can.
01/10/2013 A: keith bowers, B and B Consulting, kebowers47@gmail.com
The purpose of the baskets is to trap and remove scale that would form a crust and prevent the naphtha feed from trickling through (and increase the pressure drop.
If the previous operations do not show any trash collection, then replacement with ceramic balls should be OK. Use at least three different diameters--smallest against the catalyst then larger, then larger--as this provides better liquid distribution and greater scale holding capacity.
01/10/2013 A: kamaljit medhi, indian oil corporation limited, digboi refinery, kamaljitmedhi1975@gmail.com
We have experience with the trash baskets at our Heavy Naphtha NHDT reactor. We removed the trash baskets with new grading material as per the advice of the process Licesor. However, we experienced pressure drop increase problem which was so frequent that cycle length got reduced to 4-8 months only. A lot of theories came for the causes of the increased pressure drop like coker Naphtha processing, rust formation, compression of reactor bed due to frequent flow variation etc. However when we opened the reactor bed, no sticky material was found at the top of the reactor bed though some rust was found.
So in April,2013 , we put the baskets back and removed all the grading material. We have not experienced any increase of pressure drop since April. Experts mas mentioned that trash baskets are old technology and better options are available. However in our case, the new and better options didn't work.