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Conversion of H2S to Sulfates using Seawater

Conversion of H2S to Sulfates using Seawater

Conversion of H2S to Sulfates using Seawater

(OP)
Is anyone familiar with a reference for a process to take sour gas from an amine unit offgas stream and convert the H2S to Sulfates using seawater?

RE: Conversion of H2S to Sulfates using Seawater

Hmm I maybe off here but after you combust H2S you get SO2 and then you scrub it with sea water and the results are sulfates is that what your getting at?

RE: Conversion of H2S to Sulfates using Seawater

(OP)
Actually there is a process for scrubbing SO2 from flue gas called the Flakt-Hydro process. It was developed by Norsk-Hydro and ABB Environmental back in the 70's. Just wondering if any one had used it and had any feed back on lessons learned and real world versus theoretical design parameters.

RE: Conversion of H2S to Sulfates using Seawater

Since seawater is typically basic and slightly buffered at pH>7 values, and contains dissolved oxygen, could this link be of interest?

http://aslo.org/phd/dialog/1997January-32.html

RE: Conversion of H2S to Sulfates using Seawater

Thats a really interesting process, particually if you are trating sour gas offshore. Let me know what you find

RE: Conversion of H2S to Sulfates using Seawater

Dear TexasPE,

I found your post quite interesting.  I have a patented process, now owned by Ashland Chemical, for converting H2S to an insoluble sulphide or sulphate form.  It requires injection of an oxygen scavenger.  It worked well in a NG salt dome storage facility that had high H2S in the pipeline (greater than OSHA limits of 10 ppm).

However, keep in mind that most sour gas/oil is produced with "produced water."  Produced water has a very high sodium chloride (salt) content.  But the H2S is still abundent.  If indeed seawater scrubbed H2S, then refineries wouldn't be spending billion of $ to upgrade and remove sulfur from diesel.  Likewise, the H2S would be removed in the desalter if this were the case.  Then there would be no need for the Claus plant to convert H2S to SO2 and/or sulfur, then convertthe sulfur or SO2 to SO3 and finally to sulphuric acid for the Alky plant.  Likewise, you would also eliminate the SAR plant.

And all of the H2S now sulfate would flow from the desalter to the wastewater treatment plant(WWTP).  The sulfate of course would not be converted back to H2S by sulfate reducing bacteria, because the WWTP would operate very effectively.

Now, if you flow the entire stream through an electrolysis cell, such as diaphram cell (chlor-alkali plant), then when you generate chlorine, the chlorine will oxidize the H2S.  Likewise, any SO2 present will neutralize the chlorine.  But remember, if you don't remove the ammonia prior to the cell, you will form nitrogen trichloride - a chlor-alkali plant's worse nightmare - it explodes violently when compressed or exposed to UV light.  see US patent #5,832,361.

Sincerely,
Todd
www.oxilume.com  ;

Todd
www.oxilume.com

RE: Conversion of H2S to Sulfates using Seawater

This is interesting subject that is totally new for me.
Since I know a process of removing acid gases H2S and CO2 in ethylene plants by caustic 20% NaOH in a packing or trays  columns to convert H2S into sodium sulphate and water as well as CO2 into sodium carbonate and water
Please once you have got info. on the removal of H2S by seawater, let's know.

Regards

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