The structure of the ring tunnel kiln and the selection of thermal insulation cotton
The requirements for the kiln roof structure: the material should withstand high temperature for a long time (especially the firing zone), be light in weight, have good thermal insulation, have a tight structure, no air leakage, and be conducive to the reasonable distribution of airflow in the kiln. The general tunnel kiln body is divided from front to back into a preheating section (low temperature section), a firing and roasting section (high temperature and short), and a cooling section (low temperature section), with a total length of about 90m~130m. The low temperature section (about 650 degrees) generally uses the 1050 ordinary type, and the high temperature section (1000~1200 degrees) generally uses the standard 1260 type or 1350 zirconium aluminum type. The ceramic fiber module and ceramic fiber blanket are used together to make the structure of the ring tunnel kiln thermal insulation cotton. The use of ceramic fiber modules and layered blanket composite structure can reduce the temperature of the outer wall of the furnace and extend the service life of the furnace wall lining; at the same time, it can also level the unevenness of the furnace lining steel plate and reduce the cost of the insulation cotton lining; in addition, when the hot surface material is damaged and an unexpected situation occurs and a gap is generated, the flat layer can also play a role in temporarily protecting the furnace body plate.
Advantages of using ceramic fiber module lining for circular tunnel kiln insulation cotton
1. The volume density of ceramic fiber lining is low: it is more than 75% lighter than the lightweight insulation brick lining and 90%~95% lighter than the lightweight castable lining. Reduce the steel structure load of the kiln and extend the service life of the furnace.
2. The thermal capacity (heat storage) of ceramic fiber lining is low: the thermal capacity of ceramic fiber is only about 1/10 of that of lightweight heat-resistant lining and lightweight castable lining. The low thermal capacity means that the kiln absorbs less heat during reciprocating operation, and the heating speed is accelerated, which reduces the energy consumption in the furnace temperature operation control, especially for the start-up and shutdown of the furnace.
3. Ceramic fiber furnace lining has low thermal conductivity: The thermal conductivity of ceramic fiber furnace lining is less than 0.1w/mk at an average temperature of 400℃, less than 0.15w/mk at an average temperature of 600℃, and less than 0.25w/mk at an average temperature of 1000℃, which is about 1/8 of lightweight clay bricks and 1/10 of lightweight heat-resistant linings.
4. Ceramic fiber furnace lining is easy to construct and easy to operate. It shortens the construction period of the furnace.
Detailed installation steps of circular tunnel kiln insulation cotton
(1) Rust removal: Before construction, the steel structure party needs to remove rust from the copper plate of the furnace wall to meet the welding requirements.
(2) Line drawing: According to the arrangement position of the ceramic fiber module shown in the design drawing, lay out the line on the furnace wall plate and mark the arrangement position of the anchor bolts at the intersection.
(3) Welding bolts: According to the design requirements, weld the bolts of corresponding length to the furnace wall according to the welding requirements. Protective measures should be taken for the threaded part of the bolts during welding. Welding slag should not splash onto the threaded part of the bolts, and the welding quality should be ensured.
(4) Installation of flat blanket: Lay a layer of fiber blanket, and then lay the second layer of fiber blanket. The joints of the first and second layers of blankets should be staggered by no less than 100mm. For the convenience of construction, the furnace roof needs to be temporarily fixed with quick cards.
(5) Module installation: a. Tighten the guide sleeve into place. b. Align the center hole of the module with the guide tube on the furnace wall, push the module evenly perpendicular to the furnace wall, and press the module tightly against the furnace wall; then use a special sleeve wrench to send the nut along the guide sleeve to the bolt, and tighten the nut. c. Install other modules in this way.
(6) Installation of compensation blanket: The modules are arranged in the same direction in the folding and compression direction. In order to avoid gaps between modules in different rows due to fiber shrinkage after high-temperature heating, compensation blankets of the same temperature level must be placed in the non-expansion direction of the two rows of modules to compensate for the shrinkage of the modules. The furnace wall compensation blanket is fixed by the extrusion of the module, and the furnace roof compensation blanket is fixed with U-shaped nails.
(7) Lining correction: After the entire lining is installed, it is trimmed from top to bottom.
(8) Lining surface spraying: After the entire lining is installed, a layer of surface coating is sprayed on the surface of the furnace lining (optional, which can extend the service life of the furnace lining).
Post time: Apr-10-2025
