2 replies to this topic

[Venkat @89]

Our Vaccum gas oil hydrotreater feed contains CCR 0.85%wt and Asphaltenes <300ppm and hydrotreated VGO product contains CCR <500ppm.

How does reduction of CCR in VGO hydrotreater is achieved? Is it by formation of coke on catalysts or is it by changing the CCR forming compound nature to non CCR forming compound or in any other mechanism of reduction of CCR without coke formation?

[PingPong]

CCR 0.85 %wt of is very high for VGO. Seems not in line with 300 ppm asphaltenes.

[Venkat @89]

CCR 0.85 %wt of is very high for VGO. Seems not in line with 300 ppm asphaltenes.

My feed blend says CCR as 0.85% and C7 Asphaltenes as  < 0.03% with 58% total aromatics( Approx > 20% polyaromatics). As per your experience what would be the right figures of asphaltenes, if it has to contribute 0.85wt% CCR?

 

I also want to understand, How does reduction of CCR in VGO hydrotreater is achieved? Is it by formation of coke on catalysts or is it by changing the CCR forming compound nature to non CCR forming compound or in any other mechanism of reduction of CCR without coke formation?

 

If the CCR reduction is purely by coke lay down, then as per my throughput of the unit, approx 3.825 tons/hr coke lay down in the reactor shall happen, which would almost fill the porosity of the catalyst and choke the bed, which would end up in shutdown of the unit in few days of operation.

 

I presume it CCR reduction is through other way out.  As the posted feed CCR values are contributed by heating the feed stream in absence of catalyst in lab, in presence of catalyst the CCR causing molecules would chose another route( Hydro-de aromatization)  to become less sensitive to cause CCR after treatment. Kindly guide me and correct me, if I am going wrong. Thanks.

Edited by Venkat1989, 20 January 2023 - 04:56 AM.