Q & A > Question Details
What are the factors influencing the NHT catalyst performance towards nitrogen removal? And what is the most severe poison metal?
07/10/2008 A: Samuel Sinanan, IPSL, Samuel.Sinanan@ipsl.co.tt
Generally denitrogenation reactions are favoured by higher reactor temperatures than HDS. However a higher hydrogen partial pressure will also favour nitrogen removal. Also a NiMO catalyst gives better nitrogen removal than a CoMo for the same LHSV, ppH2 and temperature. I would say arsenic is the most severe catalyst poison. Silica is bad too.
06/03/2008 A: Mukesh Patel, Reliance Industries Limited, mukesh.patel@ril.com
Normally Desulphurisation and denitrification are main consideration in NHT, however, denitrification requires more severity than desulphurization.
Analysis of feed streams will help in knowing which the metal affecting you the most since it depends on the type of crudes processed. Of course Silica is one of them which can come along with cracked stream
18/02/2008 A: Randy Alexander, EURECAT, randy.alexander@eurecat.com
The most common poison we see affecting NHT catalysts is Silica. This contaminant typically comes from the anti-foam agent used in the coker upstream.
Unfortunately Si is very difficult to remove from spent catalysts with regeneration. Spent catalysts are normally sent for metals reclaim if the Si level is above 1.5%.