Application of Fused Cast Alumina Block in Oxy-fuel Furnace Crowns

The crown of an oxygen fuel glass furnace is exposed to the conditions of erosion of high temperature alkali vapor and batch dusts, and load. A better high temperature creep resistance is key for the crown blocks of the Oxy-fuel glass furnaces. Fused cast alumina block has been now used as crown refractories in oxy-fuel furnaces for several years.

Oxy-fuel technology involves the replacement of the combustion air with oxygen (>90 % purity). The technique can be used with either natural gas or oil as the fuel, although the use of gas is more common. In the glass industry, oxy-fuel technology offers advantages including increased productivity, noise reduction, reduced melting times, and glass quality improvements. However, it may increase refractory wear, which may affect the product quality by increasing silica corrosion at the crown of the furnace, and decrease furnace life, oxygen production costs, and potential problems related to conversions from regenerative furnaces.

Fused cast alumina block for crown application in glass industry is commercially available in two types, alpha-beta and beta alumina. Fused cast alumina blocks have high refractoriness, spall resistance, and low levels of porosity and possess low levels of glassy phase in their structure, making them less susceptible to deformation by the mechanisms of creep.

Due to their high thermal conductivity, heat flow through a furnace crown composed of fused cast alumina is higher than through traditional silica crowns, affecting back-up insulation designs and cooling methods employed on the exterior of the furnace.

In conventional(air-fuel-fired) furnaces, alpha-beta alumina has been used primarily in glass contact applications in applied exclusively in superstructure application. In oxy-fuel furnaces both types of refractories have been used for crown and superstructure applications. The alpha-beta alumina blocks have been exposed to a much wider range of temperature, stress(span), atmospheric chemistry, and length of campaign than beta alumina blocks. Fused cast Alpha-beta alumina block has been used for oxy-fuel furnaces crowns in specialty, float and container glass furnaces.

Sunrise Refractory offers different type of fused cast Alumina blocks which are made with high-purity raw materials and advanced technology. They are ideal refractory materials for different types of glass furnaces including oxy-fuel glass furnaces.