Analysis of damage form of refractory lining in rotary kilnDate: 2019-07-22 Views:
Rotary kiln is one of the most important equipment widely used in building materials industry. The quality of its installation depends largely on the quality of refractory lining, which is also the key to ensure continuous production and product quality.
The damage of refractory lining of rotary kiln often affects the continuity of production, which is one of the common equipment accidents.
1. The role of refractory lining of rotary kiln
(1) prevent direct damage of high-temperature flame or airflow to the kiln body, and protect the kiln cylinder.
(2) prevent the erosion of kiln body by harmful substances (C0, S02).
(3) prevent erosion of kiln body by materials and airflow.
(4) reduce the temperature of the kiln to prevent oxidation and erosion of the kiln.
(5) it has the function of heat storage and insulation.
(6) it can improve the performance of hanging kiln skin.
2. The damage form of refractory lining
2.1 common forms of damage
Due to the comprehensive effects of mechanical stress, material friction, thermal stress, air flow and chemical erosion, the refractory lining of rotary kiln often suffers from the following problems:
(1) long-term mechanical rotation gravity centrifugal rate effect, high temperature effect and impact friction of stone lead to prefabricated block distortion, material shedding, thickness reduction, so that the filled refractory bricks between the blocks deformation, falling off.
(2) melting loss of high temperature calcining layer.
(3) the airflow with large temperature difference inside the kiln makes the dust become lumps and bonded to the surface of the refractory material by high-temperature firing. When the kiln body rotates, the gravity separation makes the refractory material part peel off, the brick lining becomes thinner, the temperature of the kiln body increases, the steel structure changes to different degrees, and the service life of the kiln body is reduced.
2.2 probability of various damages
The German refractory technology company conducted a large experimental study on the refractory material after use, and calculated the probability of the main causes of damage:
(1) mechanical stress accounts for 37%: it is caused by cylinder deformation and thermal expansion of bricks.
(2) chemical erosion accounted for 36%: it was caused by silicate and alkali salt of clinker.
(3) thermal stress accounted for 27%: caused by overheating and thermal shock.
With different kiln type, operation and kiln lining in the kiln location is not the same, the role of the above three factors are not the same, mainly depends on the flame, kiln material and kiln cylinder body in the operation of the deformation state, so that the lining bears a variety of different stresses.