Q & A > Question Details
What is the maximum cracked feed (LCO+LCGO) percentage that can be processed in the DHU unit?
25/01/2014 A: Prabhakar Reddy Seerapu, SATORP, redi_nfcl@yahoo.co.in
Yes the % of cracked feed that can be processed in any unit is purely dependent on many factors like reactor catalyst design,bromine number of feed specified, recycle gas compressor capacity and make up gas supply flow etc.
In our diesel hydrotreater when we start processing more LCGO,delta T across the reactor top bed raises quiet good and the quench requirement in the beds raises.so compressor should be capable enough to supply enough quench flow.Licensor specified us not the exceed the delta T of 30 Deg.c in the bed which it is designed for.As every one knows with increase in the cracked feeds,make up gas requirement also increases which could be the other limitation.
Another last thing to consider is "Bromine Number" of the feed processed.some units are specified indirectly with the cracked feed to be processed in the feed.so please check if they mentioned any maimum bromine number of the feed in the feed design.
27/11/2013 A: NEERAJ Singh, HPCL, neerajsingh1@hpcl.co.in
As answered by Mr.Eric, it totally depends on your unit design. Increasing LCGO or LCO in feed will increase olefins in your feed,which in turn require more hydrogen, also heat of reaction will increase considerably. Your exotherms inside reactor will be high. So, Unit can be designed for 100% LCGO also.
04/10/2013 A: Arvinder Singh Sahney, Indian Oil Corporation Ltd, sahneyas@yahoo.com
we have an operating Diesel hydrotreating unit with > 80% cracked feed.
03/10/2013 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
As Eric points out, it is a matter of maintaining a proper reactor temperature profile. In the case of naphtha, units with 100% cracked stocks have been reported as operating well.
02/10/2013 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
It depends on lots of factors including ability to quench reactor delta T, hydrogen availability, sulfur specs, and reactor design (pressure and LHSV). Cracked stocks tend to have high hydrogen consumption with corresponding heat release and higher concentrations of difficult to remove benzothiophene compounds. If a unit is designed for it, 100% cracked diesel can be processed.