Sulfuric Acid and Fertilizer could be Better Choices than Wallboard Gypsum - Hot Topic Hour Yesterday

The prices of sulfuric acid and ammonium sulfate have risen significantly. By-product sales have become a significant revenue producer for plants with SO₂ off gases. A number of coal-fired power plants around the world are now making sulfur, sulfuric acid, or ammonium sulfate.

There is also increasing interest in using calcium sulfate as a fertilizer rather than as gypsum wallboard.

The speakers who conveyed this latest intelligence were

Colin Ryan, CanSolv

Patrick Polk, Haldor Topsoe

Amy Evans, Marsulex

Warren Dick, Ohio State University

Bill Ellison, Ellison Consultants

Biographies and pictures are displayed at hyperlink  Bios, Photos and Abstracts 

The webinar started with some history provided by Dale Stevenson of Public Service of New Mexico. “Here at San Juan Generating Station, our first generation of FGD (which went in service in 1978) we used soda ash as an absorption media, evaporated off the SO₂, which was then reacted with natural gas, and converted to molten sulfur. In 1982, we built a sulfuric acid plant, then the SO₂ stream was fed to the acid plant, where we made 93 percent grade sulfuric acid. The process was known as the “Wellman-Lord” process. The sulfur plant was an Allied design and the acid plant was a Davy design. Overall, the process was expensive to operate and maintain, there were safety issues, and the prices for the products produced (sulfur, sulfuric acid, sulfates) were sold at low prices.

With that said, the sulfuric acid plant worked well. We sold the acid specified as ‘water clear.’ ‘Smelter plant acid’ in comparison tends to be off-color, sometimes as dark as coca-cola. I think with some certified analysis, it could have been sold as reagent grade. The SO₂ stream to the acid plant was basically 80 percent SO₂ and 20 percent water vapor. Sulfuric acid plants like to run on about a 10 percent concentration, so we diluted with air. In 1998 we converted our existing absorbers to limestone based scrubbers, which work well with less maintenance cost and fewer safety issues.”

This set the stage for discussion of newer technologies and changes in the demand for by-products.

Colin Ryan listed the large number of installations of the CanSolv process including a coal-fired boiler with a flow of 936,000 Nm₃/hr in China which is starting up this month. A venturi scrubber precedes the absorber because of the high particulate load. The amine system has a capital cost as low as $60/kW in China and $200/kW in the U.S. It is capable of producing pharmaceutical grade quality SO₂. End products can be SO₂, sulfuric acid or sulfur.

Patrick Polk of Haldor Topsoe described the SNOX system that combines both NO_x reduction and SO₂ capture. There are seven of these systems in operation. But there are over 60 systems where just the SO₂ is captured and over 500 systems using the Haldor Topsoe NO_x catalyst. The Elsam power plant in Denmark has been operating a 300 MW SNOX system since 1991.

Amy Evans announced a new order for the Marsulex ammonium sulfate scrubbing system from a Chinese refinery. She reviewed the history starting with the Dakota Gasification system. With the increased value of ammonium sulfate the system has levelized cost advantages and eliminates solid and liquid waste problems. Marsulex offers the system on a BOOM basis thereby taking risks otherwise borne by the utility. She cleared up the point as to why a wet precipitator is required in some installations and not others. It depends on the SO₃ content in the flue gases. At Dakota Gasification with 70 ppm SO₃ there is a visible plume that is eliminated with the WESP.

Warren Dick of Ohio State explained why gypsum has advantages over lime and limestone as a soil amendment. It has advantages in no-tillage crop production, mine reclamation, forest plantations, reclamation of saline soils, cover for landfills and others. He did agree that in certain situations it would be desirable to separate out mercury, selenium and certain other contaminants. But in general some of the metals would be beneficial additions.

Bill Ellison discussed ammonium sulfate granulation with rotary pelletizers for minimizing losses during transportation. He also discussed a 300 MW electron beam system in Poland which is now under construction and a Lextran/Ludan system developed in Israel.

The individual power points are posted in the FGD Decision tree and can be accessed in the branches listed below.

 Colin Ryan - Cansolv

FGD Continuing Decision Process For: Products

Gas Absorption Solutions, presented by Colin Ryan, Hot Topic Hour August 21, 2008.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Colin Ryan - CANSOLV McIlvaine Hot Topic Aug. 21, 2008.pdf

Patrick Polk – Haldor Topsoe

FGD Continuing Decision Process For: Products

Presentation of Topsoe WSA/SNOX Technology presented by Patrick Polk, Hot Topic Hour August 21, 2008.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Patrick Polk - Haldor Topsoe.pdf

Amy Evans - Marsulex

FGD Continuing Decision Process For: Products

Ammonium Sulfate Wet FGD - presented by Amy Evans - Marsulex - Hot Topic Hour August 21, 2008

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Amy Evans - Marsulex - Hot Topic Hour August 21, 2008.pdf

 

Warren Dick – Ohio State University

FGD Continuing Decision Process For: Options

Flue Gas Desulfurization (FGD) Gypsum as a Soil Amendment, presented by Warren Dick, Ohio State University - Hot Topic Hour August 21, 2008

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Warren Dick, Ohio State University - Hot Topic Hour August 21, 2008.pdf

 Bill Ellison – Ellison Consultants

FGD Continuing Decision Process For: Ammonium Sulfate

Guidance and Insights in FGD Alternatives presented by Bill Ellison, Hot Topic Hour August 21, 2008. FGD Alternatives With High-Value, Commercial, Sulfurous Byproduct Yield

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Ellison_guidance_and_insights August_21.htm