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Currently, I am trying to reduce the sulfur concentration from the hydro-treated naphtha. After reading up a few articles I came to the conclusion that the sulfur concentration is due to improper stripping of H2S from the stripper column. I have to improve the performance of the stripper column to reduce the sulfur concentration by adjusting pressure and R/F.
How do I proceed? Is there any other sources of sulfur that I have to pay attention to?
 
Answers
08/11/2018 A: keith bowers, B and B Consulting, kebowers47@gmail.com
Steam Stripping is essential to remove H2S if that is the problem. I well remember when a 'hot shot new supervisor' eliminated the 10,000#/hr of stripping steam on a 30,000 B/D Jet A hydrotreater. His reason was to reduce energy use/cost as there was no change in the Jet A flash point across the stripper so stripping was not needed. By Monday morning, after pulling the stripping steam Friday, over 200,000 Bbl of Jet A was Doctor Positive and could not be shipped up the Colonial Pipeline and had to be reworked.
06/07/2018 A: Krishna Rao Pulugurti, Retired/Consultant, pkrao2012@yahoo.com
You can gauge the presence of hydrogen sulfide downstream of hydrotreater by lead acetate. If hydrogen sulfde is present, the lead acetate will turn black. If there is no black color, then then presence of hydrogen sulfide is ruled out. The reason is something else which needs investigation.
05/07/2018 A: Muhammad Akhtar, Orpic, mbadgk@gmail.com
First of all you have to identify the sulfur contaminants. If it is H2S contamination than Stripper adjustment will work. But if it is mercaptane than it is to be dealt by adjusting the reactor condition or rectifying the leak (if any) across the CFE.
Can you tell me the reactor configuration and Reactor temperature condition. Feed and product contamination level.
05/07/2018 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Mercaptan recombination can be a source of sulfur if the reactor temperature is too high. H2S reacts with olefinic cracking products to form mercaptans.
05/07/2018 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
With an operating unit, the primary variable to achieve target conversion of sulfides to H2S is RIT. If H2S is not being stripped, work the stripper more. If there is a reboiler, increase the heat input, with corresponding increase in reflux. Continue until the calculated load is 85-90 % of flood. Higher than that will not help due to entrainment. More reactor inlet pressure would help conversion, but you must be as high as possible now. Increasing hydrogen circulation probably will not help but theoretically would. That is all you can do with an operating unit except to reduce feed rate.
05/07/2018 A: Bruce Carr, Suncor Inc, matukaze1@hotmail.com
Is it Sulfur or H2S?....Big difference..... If it's elemental Sulfur your Hydrotreater is not working properly... need to adjust reactor temperatures....If it's too much H2S then you may need to inject more water into the outlet as it obviously isn't absorbing enough of the produced H2S... In your stripper if you are using stripping steam make sure the steam is dry... poor quality steam will prevent proper stripping...