tunnel kilnIt is a continuous industrial kiln named after its long tunnel shape. As one of the most important firing equipment in the fields of modern architectural ceramics, daily ceramics, refractory materials and other fields, the tunnel kiln has become a pillar equipment for mass production in the building materials industry due to its efficient and stable production characteristics.
How tunnel kiln works
The kiln body of the tunnel kiln is in the shape of a long tunnel, ranging from tens to hundreds of meters in length. The kiln car carries the products to be fired. It enters the kiln head, moves slowly along the kiln road, passes through the preheating zone, firing zone and cooling zone, and finally exits the kiln at the end. The entire firing process is carried out continuously in the kiln, realizing streamlined production.
In the preheating zone, the workpiece is preheated by the hot air flow from the firing zone and gradually rises in temperature; in the firing zone, the high temperature generated by fuel combustion completes the firing reaction of the product; in the cooling zone, cold air enters the kiln, absorbs the heat of the product for preheating, and at the same time, the product gradually cools to the kiln exit temperature. This countercurrent heat exchange principle makes the tunnel kiln have high thermal efficiency.
Main types of tunnel kilns
According to different classification standards, tunnel kilns can be divided into various types:
Classification by heat source：
- Gas-fired tunnel kiln: using clean fuels such as natural gas and generator gas, with precise temperature control and good environmental protection
- Coal-fired tunnel kiln: using clean coal or pulverized coal as fuel, the investment cost is low
- Electric tunnel kiln: suitable for firing small batches of high value-added products without waste gas emissions
Classification by kiln car structure: Truck-mounted tunnel kiln and roller-bottom tunnel kiln.
Technical characteristics of tunnel kiln
Tunnel kilns have the following significant advantages in industrial production:
1. Large production capacity: The continuous production method makes the tunnel kiln’s production capacity much higher than that of the intermittent kiln.
2. Low energy consumption: Counterflow heat exchange principle and good insulation structure enable thermal efficiency to reach 30% to 40%
3. Product quality is stable: The temperature curve is fixed, the firing process is stable, and the product quality is consistent
4. High degree of automation: Equipped with automatic temperature control system to realize full automation operation
5. Low labor intensity: Automatic loading and unloading of the kiln reduces manual operations and labor intensity.
Application fields of tunnel kiln
Tunnel kilns are widely used in the firing process of the following industries:
- architectural ceramics: Firing of ceramic tiles, ceramic tiles, floor tiles and other building decoration materials
- Daily ceramics: Firing of tableware, tea sets, and craft ceramics
- Refractory materials: Firing of refractory bricks and refractory castables
- Electronic ceramics: Firing of ceramic substrates and electronic components
- powder metallurgy: Sintering of metal powder products
The development direction of tunnel kiln
Modern tunnel kilns are developing in the following directions:
Save energy and reduce consumption: Use new insulation materials, optimize the kiln structure, improve the combustion system, and reduce energy consumption per unit product. The heat consumption of some advanced tunnel kilns has dropped below 800kcal/kg.
Environmental protection and emission reduction: Equipped with desulfurization and denitrification devices and dust removal equipment to reduce waste gas emissions; use clean energy to replace coal to reduce pollutant emissions.
Intelligent control: Realize precise control of the firing process through the PLC control system and temperature sensor network; apply artificial intelligence technology to optimize the firing curve and improve product quality.
We provide one-stop service from kiln design, equipment manufacturing to installation and commissioning. We can provide the most optimized tunnel kiln solution according to your product type and production capacity requirements. Welcome to call us for discussion.
