“Selecting FGD Scrubber Materials” was the Hot Topic on December 19, 2013
It is vital to select the correct materials for the FGD system in order to minimize corrosion and abrasion. There are big differences among materials in terms of cost and performance. Three experts provided insights on the options.
Ed Wesson, Specialist in Composite Corrosion Applications Engineering at AOC Resins, explained that composites are very successful in slurry applications and flue stack liners in coal-fired power plants and are now being used for major structural elements too. The FRP resin supplier is a chef who puts in the right ingredients for success. He adds inorganics to provide abrasion resistance and has to balance fire retardance against corrosion impacts. But with the right recipe, FRP has the following advantages:
James Crum, Consultant at Special Metals, covered crevice corrosion and repair solutions with cladding as well as some options for super austenitic as opposed to high nickel material. The problems with 2205 have been resolved by substituting other materials. High nickel alloys solve the problem but they are expensive. Super austenitic alloys are less expensive but equally corrosion resistant. Here are two power plants that successfully used the alloy:
FGD Chimney Flue in North Dakota – Like their counterparts at Arizona Public Services, (APS) the FGD project team at Great River Energy selected alloy 27-7MO plate for construction of ducting and the chimney flue at the Coal Creek Station in Underwood, ND. Their reasoning was similar to that of the APS team ... alloy 27-7MO offered corrosion resistance adequate for the application at a significant cost savings over alloy C-276. SMC supplied over 200,000 lbs. of alloy 27-7MO plate through the exclusive distributor for alloy 27-7MO products, Corrosion Material, Inc. Like the APS project, Custom Steel Fabrication formed the plate and welded it with INCO-WELD filler metal 686CPT.
FGD Chimney Flue in Arizona - Alloy 27-7MO plate was used for construction of the flue for the chimney for the FGD system at the Arizona Public Service’s (APS) Cholla Station. APS opted for alloy 27-7MO over alloy C-276 as a cost control measure. Alloy 27-7MO was judged to offer performance equivalent to alloy C-276 for this application at a significant cost savings. Over 100,000 lbs. of plate was fabricated by Custom Steel Fabrication in Columbia, TN. All welding was done with INCO-WELD filler metal 686CPT. Despite upset conditions during initial system start-up, after over two years service the flue condition is excellent with no evidence of corrosion.
Luis Granes, International Sales Manager Sauereisen Inc., covered a range of material linings for FGD shells and components. His company offers
§ Inorganic mortars
§ Inorganic refractories with an organic membrane
§ Organic epoxy and vinyl ester linings
The inorganic mortars (gunite) and the inorganic refractories (brick) are used in the stack. The organic linings are used in the scrubber duct work. The Chinese have opted for organic linings due to the speed at which they can be installed.
Bios, Photos and Abstracts are as follows: BIOS, ABSTRACTS, PHOTOS - 12-19-13.htm
The individual presentations are as follows:
§ Selecting FGD Scrubber Components Webinar - Hot Topic Hour December 19, 2013 (Webinar Recording dated: 12/19/2013)
§ Accelerated Crevice Corrosion of Duplex Stainless Steels in Wet Limestone FGD Environments by Jim Crum, Special Metals - Hot Topic Hour December 19, 2013 (Presentation dated: 12/19/2013)
§ Composites - Applications and Manufacturing Process in Design and Maintenance by Ed Wesson, AOC Resins - Hot Topic Hour December 19, 2013 (Presentation dated: 12/19/2013)
Selecting FGD Scrubber Components by Luis Granes, Sauereisen - Hot Topic Hour December 19, 2013 (Presentation dated: 12/19/2013)