Talk:Claus process

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Reasons for reverting edit by User:Otispa about Morpholine[edit]

I believe the edit about Morpholine was well intentioned. I reverted it because:

  • It was completely out of context. This is an article about the Claus process ... it is not about problems with the DGA process.
  • It was very poorly formatted by someone who seems not to have taken the time to learn how to write as per the Wikipedia manual of style.
  • The subject matter would be better written as a separate article on the DGA process. At best it only deserves a sentence or two in this article.
  • The edit refers to a "Case History" ... but includes no reference as to who wrote that case history or where it was obtained.

If User:Otispa would create a personal sandbox and write a brief article (in that sandbox) about the DGA process and its problems, I would be happy to help him format it in Wikipedia style. I would also be happy to boil it down into one or two sentences for inclusion in this article. But first, I would need to have a reference to back up the "Case History." - mbeychok 00:30, 13 February 2007 (UTC)


I'm working on a project to design a unit using this process, so I appreciate the writeup. One thing I've not been able to find is, why is this called the "Claus Process"? I would guess a pretty smart guy named Claus figured this out. Does anyone have any more historical information that could be added to the article? Thanks. Ultimate ed 13:30, 8 June 2007 (UTC)

The process was invented by Carl Friedrich Claus, a chemist working in England. A British patent was issued to him in 1883. The process was later significantly modified by a German company called I.G.Fabenindustrie A.G. See this online citation [1] - mbeychok 16:34, 8 June 2007 (UTC)

how to remove H2S from sour gas containing less than 25% H2S[edit]

Claus process is only applicable for rich H2S content (above 25%)sour gas. What processes are used to remove lower H2S content sour gas? Pangsm 14:25, 24 August 2007 (UTC)

The SulFerox process (licensed by Shell Oil) is said to be suitable for sulfur conversion/recovery from gas streams containing very low concentrations of H2S. I am not sure, but I believe that the LoCat process (licensed by Merichem) is also suitable for such applications. - mbeychok 15:58, 24 August 2007 (UTC)
I'm a little late on this one here, but the >25% H2S in the feed is for the standard, straight-through set up. There are mutliple configurations that you can use for a Claus plant that will allow you to operate with a leaner feed. 15-30% H2S feeds can be handled with either a split flow configuration or "straight through" with an air/feed preheat. 10-15% H2S feeds can be handled with a split flow configuration AND a preheat. 5-10% feeds need a split flow configuration, feed/air preheat, and fuel addition. (Or a direct oxidation method like Mbeychok mentioned). Feeds of <5% require a direct oxidation method (or need to be fed to an amine treatment unit and recycled back to the Claus plant in higher concentrations). These rules of thumb are from the Gas Processors Association Handbook.
...I guess I should actually just add this to the article...Goatchze (talk) 19:36, 4 February 2008 (UTC)
The SulFerox process is actually no longer supported by either developers, Dow or Shell. The LO-CAT Process can effectively treat gases containing only ppm levels of H2S up to nearly 100%, with removals as high as 99.99+%. It is also effective as a process for Claus Tailgas treatment <> to help Claus plants achieve greater than the 97% removal that the equilibrium based process can achieve on its own. -GTPTechMan (talk) 19:58, 19 September 2008 (UTC)

Purification beyond 97%[edit]

The article says this process eliminates 97% of the H2S. Does anyone know how the tail gas purification process works? How about Shell Claus Offgas Treating (SCOT)? I believe 3% H2S is still too high for the gas to be used as fuel under US environmental regs. —Preceding unsigned comment added by (talk) 09:34, 25 March 2008 (UTC)

97% refers to the recovery of H2S to elemental sulfur in the two bed Claus unit itself, NOT recovery from the original sulfur containing stream. Typically the tail gas is incinerated and is not used as a fuel. Addition of tail gas treaters can increase recovery to the 99+% range. SCOT converts any remaining sulfur species back to H2S so that they can be absorbed in an amine column and recycled back as Claus feed. Goatchze (talk) 19:36, 7 May 2008 (UTC)

Can we use H2S for Indirect fired Heaters[edit]


Am working on preperation for an EPF and the client is asking for use of the Natural gas to run the indirect fired heater, but this gas containing H2S, So I'd like to have something writtien to state that its not acceptable to use the H2S for that porpuses, as the fire wil result on SO2 which is toxic same as H2S.

Thanks for the Help —Preceding unsigned comment added by (talk) 10:01, 3 February 2010 (UTC)

Flow diagram is wrong[edit]

The flow diagram shows air direct to third catalytic stage. That would suggest this drawing is actually a SuperClaus flow diagram. — Preceding unsigned comment added by (talk) 03:38, 21 August 2012 (UTC)

There are many versions of the Claus process for converting hydrogen sulfide to elemental sulfur. There are probably additional other versions, but these come to mind:
  • Straight-through Claus process
  • Split-flow Claus process process
  • Claus process with 2 reactors
  • Claus process with 3 reactors
  • Claus process using oxygen rather than air (OxyClaus process)
  • SuperClaus process

It would not have been feasible, in my opinion, to include flow diagrams for all of the possible versions, so one diagram was used.

After all, the SuperClaus version is a Claus process and thus the flow diagram is not wrong. mbeychok (talk) 06:48, 21 August 2012 (UTC)

The SuperClaus process is not really a Claus process. It is more like a tail gas treating process because the working of the process is different than for the Claus process (direct oxidation of H2S over a special catalyst bed instead of reaction of H2S with SO2). The Claus process can be installed with 2 or 3 reactor stages. 2 stages gives approximately 97% sulfur recovery efficiency and 3 stages gives approx 98% sulfur recovery efficiency. Now it looks like that the third reactor stage need air (oxygen). Operating the Claus unit in oxygen excess gives a lot of operational problems (sulfur fires, burning of pyroforic iron, catalyst degradation). Adding air to the 3rd Claus catalytic reactor stage does not belong to the Claus process and is also never installed. In my opinion the diagram is confusing. — Preceding unsigned comment added by (talk) 12:11, 4 August 2014 (UTC)

Enthalpy error?[edit]

My calculation of the enthalpy of the catalytic step, using heats of formation, comes to -72.77 kJ/mol of S. The enthalpy for the thermal step (per mol of S) appears to be correct. I cannot understand how the article's value for the former was arrived at. Mine seems to make more sense, as the thermal step sends S oxidation states from -2 to +4 whereas the catalytic step is a disproportionation from oxidation states -2 and +4 to 0 (hence more neutral). Since the heat of formation of H2S from the elements is much smaller than that for SO2, it makes sense that the disproportionation should be less enthalpic than the thermal step.

Pgpotvin (talk) 04:26, 13 October 2016 (UTC)