Glass furnaces are the heart of glass factories, and their operating safety is extremely important. As a large-scale thermal complex, the maximum flame temperature of the furnace in its operating space is generally above 1600℃, and the maximum temperature of the glass liquid must reach above 1450℃. There will inevitably be some phenomena of high-temperature flame burning of the furnace body refractory materials and erosion of high-temperature glass liquid during production, which will affect the safe operation and service life of the glass furnace.

Before 2000, the production and operation cycle of the float glass furnace with the largest furnace tonnage (commonly known as "furnace age" in the industry) was mostly 5 to 8 years; with the improvement of the quality of the glass furnace main refractory materials and the advancement of glass furnace operation and maintenance technology, the operating life of glass furnaces is getting longer and longer. After 2000, the operating cycle of float glass furnaces, i.e., furnace age, generally reached more than 10 years, and the longest furnace age reached 15 years. The extension of glass furnace age can bring huge economic benefits to glass factories, and each enterprise is pursuing a longer glass furnace age under the premise of safety control.

The burning and erosion of the glass furnace during operation can be controlled and reduced through professional hot maintenance. The more common hot repair work includes side wall patching, side wall replacement, ceramic welding, nozzle brick replacement, chimney replacement, large arch and regenerator rat hole repair, regenerator wall tilt maintenance, etc.
The tuck stones under the flame nozzle are directly facing the flame impact. Although the most resistant to burning and erosion fused cast AZS blocks are used, there is also a situation of gradual burning. With the extension of the glass furnace age, the burning to a certain extent will expose the breast wall support plate of the lower part to the flame space, and even directly burn it by the impact of the flame airflow, which brings great hidden dangers to the safe operation and the lifespan of the glass furnace. Before 2000 AD, it was even the main factor that determined whether the glass furnace should end a furnace life cycle and shut down for cold repair.
In recent years, with the improvement of glass furnace maintenance technology, in the normal production and operation of the glass furnace, the replacement of the burned tuck stones under flame nozzle through hot maintenance has become a relatively mature glass furnace maintenance operation, which can effectively protect the breast wall support plate from burning and extend the safe use life of the glass furnace. In some glass furnaces, due to factors such as the quality of refractory materials or glass furnace operation flame control, the tuck stones are burned abnormally quickly. Hot replacement of some tuck stones plays a more important role.

1. Factors controlling the burning of tuck stones

2. Key points for controlling the hot replacement of tuck stones during production

Factors controlling the burning of tuck stones

The horizontal flame regenerator air combustion furnace is the most common furnace type at present, as well as the end fired air combustion furnace in some light industries. Most of them use bottom-fired burners, and their flame nozzle structures are shown in Figures 1 and 2.

1. Schematic diagram of the cross section of the port flame nozzle

2. Photo of a newly built flame nozzle on a certain line

The inspection photos of the glass furnace after cold repair and the glass furnace inspection photos of the furnace in production show that the burnout of the blast hole is serious. In actual production, the hook bricks are seriously burned, or the breast wall support plate is burned and deformed after the hook head falls off, and the support plate sinks and deforms by as much as 5mm.