Project No: FC26-07NT43097
Performer: Babcock & Wilcox Power Generation Group, Inc.


Contacts
Robert Romanosky
Advanced Research Technology Manager
National Energy Technology Laboratory
3610 Collins Ferry Road
P.O. Box 880
Morgantown, WV 26507-0880
304-285-4721
robert.romanosky@netl.doe.gov

Vito Cedro III
Project Manager
National Energy Technology Laboratory
626 Cochrans Mill Road
P.O. Box 10940
Pittsburgh, PA 15236-0940
412-386-7406
vito.cedro@netl.doe.gov

Steven C. Kung
Principal Investigator
Babcock & Wilcox
20 South Van Buren Avenue
Barberton, OH 44203-3522
330-860-6774
s ckung@babcock.com

Duration
Award Date:  08/14/2007
Project Date:  08/31/2014

Cost
DOE Share: $2,103,543.00
Performer Share: $525,886.00
Total Award Value: $2,629,429.00

Performer website: Babcock & Wilcox Power Generation Group, Inc. - http://www.babcock.com/Pages/default.aspx

Crosscutting Research - Plant Optimization Technologies

Development of Computational Capabilities to Predict the Corrosion Wastage of Boiler Tubes in Advanced Combustion Systems

Project Description

For this project, B&W will characterize the realistic combustion conditions and products in boilers. Researchers will select eight common U.S. coals that represent a wide range of coal chemistry burned in utility boilers. These coals will be combusted in Brigham Young University’s burner flow reactor (BFR) to closely simulate actual staged combustion encountered in utility boilers. During the BFR runs, gas and ash/ slag deposit samples will be collected and analyzed for each coal at the waterwall and superheater/reheater locations.

Once the conditions are defined, a series of long-term (1,000-hour) laboratory corrosion tests will follow. Researchers will expose various alloys and weld overlays of a wide range of metal compositions to laboratory conditions resembling actual boiler operating environments. Relevant corrosion data from these tests will be used to generate models to aid in the development of materials for improving the performance of boiler tubes. The modeling will produce two predictive equations, one for waterwalls and one for superheaters/reheaters, which will be used to estimate the corrosion wastage of boiler tubes as a function of different key variables such as sulfur, chlorine, alkali, ash, pyrite, and metal temperature. Application of these predictive equations will be designed to be highly versatile and applicable to a variety of coals and boiler operations.


Program Background and Project Benefits

Staged combustion is a method of reducing nitrogen oxide (NOx) emissions in boilers by controlling the combustion mixture of air and fuel. Its process conditions are particularly corrosive to lower furnace walls. Superheaters and/or reheaters are often employed in the upper furnace to reuse hot combustion gasses to further raise the temperature of steam vapor. Relatively high metal temperatures and the presence of certain metals in coal ash cause severe coal ash corrosion attack to superheater/ reheater tubes. The problem is further intensified when steam outlet temperatures of advanced combustion systems are significantly increased.

To address these corrosion concerns, the Department of Energy (DOE) National Technology Energy Laboratory (NETL) is collaborating with Babcock & Wilcox (B&W) on a project to develop corrosion models capable of predicting lower furnace and superheater/reheater tube corrosion wastage (deterioration). Because corrosion attack is activated by heat, the effect of temperature will also be investigated. Ohio State University faculty will support B&W’s efforts by contributing their technical expertise in the area of high-temperature corrosion.

A predictive tool to determine corrosion wastage rates in lower furnace and superheater/reheater tubes will aid in the design and maintenance of boilers, especially those operating at elevated temperatures, and will contribute to attainment of DOE targets for increased efficiency and reduced emissions in power plants. These improvements will help the U.S. to manage environmental issues associated with coal-fired power plants. In addition, more efficient use of domestic fuels will reduce U.S. dependence on foreign sources of energy fuels, thereby increasing national security.


Accomplishments

Major accomplishments to date include (1) all eight (8) sample coals were pulverized and delivered to Brigham Young University; (2) all eight (8) coal tests have been completed in the BFR burner: Illinois #6, Powder River Basin (PRB), Indiana #6, Ohio Mahoning #7, Kentucky #11, Pittsburgh #8, Ohio Gatling, and Beulah Zap (ND lignite) coals; (3) ash deposits of all eight (8) coals were obtained from the BFR burner and analyzed for chemical composition, particle size distribution and particle morphology; (4) gas composition sampling and analysis in the BFR reducing and oxidizing zones was completed for all eignt (8) coals burned in the BFR; and (5) laboratory-scale corrosion testing is underway on PRB, Ohio Mahoning #7, Beulah Zap lignite and Illinois #6 coals in conditions simulating the upper furnace (oxidizing zone) and lower furnace (reducing zone) regions of a coal-fired boiler using these coal types.