Energy Efficiency and Circular Economy in Glass Wool Fiberizing: Impact of Lightweight Refractory Design

This paper presents an analysis of energy savings and sustainability measures to improve the environmental performance of glass wool fiberizing, the latter being the most energy intensive production step in manufacturing glass wool thermal insulation, involving conversion of hot molten glass into fibers. The first part evaluates two refractory designs—business as usual (BAU) and modified (MOD), over four trials. BAU refractory has higher density whereas MOD is an innovative lightweight design, with lower density and improved thermal conductivity. The key operational parameters analyzed include energy demand and CO2 emissions in the fiberizing stage, along with burner pressure, temperature and fiber diameter. The results show that MOD has better thermal performance, leading to an average energy demand reduction potential of up to 10%. The second part focuses on promoting a circular economy for the end-of-life refractory, underpinned by the potential for recovery and reuse of spent refractory materials. Based on a total refractory mass of 1.2 tons for the six burners, the end-of-life refractory material recovery is estimated as 0.78 ton (65% of the aggregate). Balancing the recovery costs with the acquired value of the recovered aggregates, results demonstrate significant material and environmental cost avoidance on a 3-year refractory relining cycle.