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Treatment of H2S in acid gas

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  • 1.  Treatment of H2S in acid gas

    SENIOR MEMBER
    Posted 04-11-2018 06:47
    Gas processing plant generates acid gas from gas sweetening units (amine based) and consists predominantly CO2 and H2S. How the H2S  is treated further before mixing with residue / lean gas, for re-injection to the reservoir well?

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    Mohan Raj Sadatcharam
    Process Engineer

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  • 2.  RE: Treatment of H2S in acid gas

    SENIOR MEMBER
    Posted 04-11-2018 08:13
    Hi,take it’s easy ,there are a Mature sulfur recovery process technology of some company.

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    Han Li
    project manager
    Hualu
    Xi'an
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  • 3.  RE: Treatment of H2S in acid gas

    SENIOR MEMBER
    Posted 04-12-2018 01:42

    Its understood that , sulphur recovery process are available for high H2S content sour gas . Are economically feasible technologies available for treating acid gas of 2MMSCF with less than 5% H2S?

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    Mohan Raj Sadatcharam
    Process Engineer
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  • 4.  RE: Treatment of H2S in acid gas

    LOCAL SECTION OFFICER
    Posted 04-15-2018 22:47
    There is a wealth of information available on this topic in the published literature, but if you want quick answers, I suggest to go to  www.protreat.com/seminars.  If you are in the USA, you can call 1 281 970 2700 and speak to an expert, which is what I would do if I were in your shoes.  God Luck,

    Jimmy Kumana





  • 5.  RE: Treatment of H2S in acid gas

    SENIOR MEMBER
    Posted 04-12-2018 02:39
    Acid gas from gas sweetening plants is normally flared and combusted as the simplest means to deal with it. It can be compressed and re-injected without further treatment but you have to take a great deal of care with materials selection and the compression process itself. This is because the interaction between water, CO2, H2S and methane is not easy to predict and you could get water condensing in the compressor. There are some Canadian consultants that specialise in this type of work i remember from a previous project.

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    Simon Richards CEng,EurIng
    Principal Consultant
    Bosco Xavier Ltd
    Andover
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  • 6.  RE: Treatment of H2S in acid gas

    SENIOR MEMBER
    Posted 04-12-2018 13:42
    Mohan:  You may also want to check on the potential for an injection gas breakthrough in the reservoir. Although it would not be short term, it will increase your H2S/CO2 concentration in the production gas, which might then create an expensive corrosion problem in the existing production facilities. Check with the Reservoir engineers and check the metalurgy of the existing systems.

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    Alfredo Saettone
    Process Engineer
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  • 7.  RE: Treatment of H2S in acid gas

    SENIOR MEMBER
    Posted 04-13-2018 13:14
    ​Is this a theoretical question or an actual scenario?

    Absorption is a common method used to remove CO2 and H2S in purifying crude oil.  If you just trying to remove the gases for environmental reasons a scrubber could be used as well.

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    Kevin Poff
    Chemical Engineer
    ECBC
    East Prospect PA
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  • 8.  RE: Treatment of H2S in acid gas
    Best Answer

    SENIOR MEMBER
    Posted 04-14-2018 09:51
    There are some liquid redox technologies that can handle low quantities of sulfur and low concentrations of H2S and produce a solid elemental sulfur. Try looking up LoCat and Sulferox. They use a chelated iron based solvent. The quality of the sulfur is not Claus quality, but it has been used for agricultural applications.

    There was a very old Redox technology that used a vanadium based solvent (not environmentally friendly) called Stretford.

    You can also use a secondary amine system on the acid gas with MDEA to selectively remove the H2S and only part of the CO2 to concentrate the acid gas so that it can easily be processed in a conventional Claus SRU.

    What are the flow units 2 MMSCF per minute or hour or day or fortnight?

    There are also solid H2S removal systems (scavengers), but they generate a large solid effluent that will need to be disposed of; look up SulfaTreat.

    There are also biological systems (Bugs that convert H2S into elemental sulfur) and generate a sulfur with bug remains.

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    Charles Kimtantas
    Sulfur Tech Mgr
    Bechtel Hydrocarbon Technology Solutions Inc.
    Sugar Land TX
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  • 9.  RE: Treatment of H2S in acid gas

    SENIOR MEMBER
    Posted 04-15-2018 15:25
    Additional comment:

    I have been advised that the rate is 2 MMSCFD at 5% H2S, which is approximately 3.8 Metric ton per day of elemental sulfur [(2000000*0.05/379.48)*(32/2205)=3.8 MTPD sulfur].

    This is usually considered an good capacity for LoCat, and is probably too large for most solid and liquid H2S scavenger systems, due to fresh chemical cost and disposal cost of spent scavenger. A second amine system (MDEA) and then a Claus SRU would probably cost much more than a LoCat unit to generate an elemental sulfur product.

    I suggest you contact Merichem (http://www.merichem.com/gas) for capital and operating cost information.

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    Charles Kimtantas
    Sulfur Tech Mgr
    Bechtel Hydrocarbon Technology Solutions Inc.
    Sugar Land TX
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  • 10.  RE: Treatment of H2S in acid gas

    SENIOR MEMBER
    Posted 04-16-2018 04:26
    Thanks to one and all for sharing their valuable inputs!!!

    The outcome of series of discussions for handling low H2S in the acid gas :

    1) Can  be re-injected into the well as stand-alone or after mixing with residue gas
                         - The H2S/CO2 concentration in the associated gas is a concern.
    2) Can be flared
                         - seems to be the easiest option however the effect on continuous flaring emissions and local environmental regulations to be looked into.
    3) Can be converted to elemental sulfur of low purity by treating with Liquid redox solution.
    4) Can be converted to elemental sulfur of high purity by secondary treatment with amine / Claus SRU.
    5) Can be converted to elemental sulfur of high purity by Solid / Liquid Scavenger systems.
                             - Operating cost seems to be a  constraint.
    6) Can be converted to elemental sulfur of low purity by means of biological systems (bugs).

    I think, the acid gas H2S handling to be zeroed in on techno-commercial aspect of elemental-sulfur conversion (liquid redox solution/secondary amine-Claus SRU/Scavenger systems) vis-a-vis the flaring option.

    Looking out for more information on liquid redox solution treatment technologies like LoCat Vs Sulferox and option of continuous acid gas flaring.

















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    Warm Regards,
    Mohan Raj Sadatcharam
    Process Engineer
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