This moving grate boiler is the primary method of heating at this site, and as such the refractories require annual repair. The primary fuel source of this boiler is wood chips, fed through a series of throwers, which create significant wear on the target wall. 

Upon inspection, it was found that the target wall was in a degraded condition, as well as the side walls. Other areas of the unit were degraded, with multiple areas of steelwork exposed including the air tubes. Other areas around the wood chip throwers and entrance were also degraded due to years of damage.

During the 2021 January shutdown, after consultation and understanding of the use of this unit, a different material was used in the target wall that had similar thermal insulation properties, but higher abrasion resistance. This would minimise the damage between annual shutdowns. The material fared better than previous years, so more sections were replaced with this material.

A team of 5 workers removed and replaced the damaged refractory material. Each section had a different material used, which was appropriate for the location given the heat applied, and general wear and tear. This work was also done in conjunction with other contractors (welding damaged tubes, grate replacement) to ensure the unit would operate to the users’ requirements for another 12 months.