Tunnel Kiln Thermal Regulation and Brick Stack Collapse: Key Operation Guidelines for Stable Firing
Thermal system regulation serves as the core of tunnel kiln production operation, which refers to adjusting variable parameters inside the kiln to form a scientific and reasonable thermal environment in accordance with the characteristics of fired products and actual production standards. In daily tunnel kiln operation, temperature control is realized through multiple adjustable measures, including modifying the frequency of three key fans (smoke exhaust fan, heat exhaust fan and kiln door fan), adjusting the opening degree of pipeline gates, controlling the kiln car feeding speed, and implementing top coal feeding operations.
To ensure the continuous and stable operation of a tunnel kiln, four essential operating conditions must be met. First, the internal combustion calorific value of brick blanks shall be uniform and stable to avoid abnormal temperature fluctuations caused by uneven heat release. Second, the internal kiln temperature shall remain within the allowable fluctuation range, covering the preheating zone, firing zone and cooling zone at all kiln positions. Third, the car feeding system shall be fixed, with unchanged product types and internal combustion ratio, consistent kiln car entry intervals, and stable heat absorption of brick blanks in the preheating and firing zones per unit time. Fourth, the physical and chemical indicators of finished products shall be kept stable to guarantee standardized firing quality.
Brick stack collapse is a common and harmful fault in tunnel kiln production. Severe collapse will lead to kiln shutdown, and manual troubleshooting in high-temperature kiln environments poses great safety risks, seriously restricting production efficiency. There are four main causes of stack collapse: unstable brick stacking quality that leads to loose stacks during kiln car operation; excessive moisture content of under-dried brick blanks entering the kiln; subsidence or severe deformation of one side of the kiln track, causing kiln car tilt and stack collapse against the kiln wall; and falling refractory bricks from the kiln wall or roof, which jam between the stack and kiln wall and trigger collapse. Once abnormal conditions are found during kiln car feeding, operators must stop feeding immediately, inspect fault causes and implement targeted solutions.
Corresponding preventive and remedial measures are formulated for the above faults. Manufacturers need to optimize the brick blank drying process and strictly control the moisture content of blanks before kiln entry. Standardize brick stacking operations, adhere to the principles of flatness, straightness and stability to ensure the firmness of all incoming brick stacks. Conduct regular comprehensive inspections on kiln tracks, kiln walls and roof refractory structures, and timely repair and replace damaged components to eliminate potential safety hazards.
