Weartech SHS Thermal Spray Coating on Boiler Tubes

Waste coal is a low energy value discard that has accumulated for more than a century at anthracite and bituminous coal mines in the Northeast USA. Since the early 1990's, coal-fired power plants near these mines have been configured to burn this inexpensive fuel source in circulating fluidized bed (CFB) combustion boilers. For every 100 tons of waste coal burned, more than 60 tons of fly ash, containing chemicals such as mercury and sulfur, is produced along with emissions containing very fine nitrogen oxide particles. Plant operators feed limestone into the combustor to control the chemicals and introduce ammonia to reduce nitrogen oxide emissions. The result is erosion and corrosion damage that causes boiler tube failures and costly unscheduled outages.

Inside a CFB boiler at a coal-fired power plant in Pennsylvania, a thermal spray coating field trial comparison was conducted on a section of boiler tubes where the most severe erosion damage occurs. Weartech SHS7170 WTWAS was applied to a 7 x 5 ft. (2.1x 1.5 m) section of boiler tubes between two LMC Armacor™ thermal spray coatings of equal size.

When the boiler tubes were inspected during a scheduled outage after 9 months of service, the Weartech SHS7170 WTWAS coating did not show any signs of erosion or corrosion damage while competitor coatings showed erosion damage requiring repair.