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Reasons and treatment of snowman in grate cooler

Date:2019-12-24 14:25 Source:cementepcViews:

I. What is a snowman


The so-called snowman in the grate cooler is an image name. In fact, the clinker under the rotary kiln barrel of the front wall of the grate cooler cannot be transported away, which causes it to accumulate higher. In severe cases, it can be blocked at the kiln mouth and cause the kiln Clinker cannot be drained.


 

II. The main causes of snowmen


1. Improper coordination of grate cooler and rotary kiln

The horizontal position of the grate cooler and the rotary kiln must be coordinated to ensure that the longitudinal centerline of the grate cooler and the longitudinal centerline of the rotary kiln are offset by a reasonable distance. If there is no experience, designing the vertical centerline of the grate cooler and the rotary kiln on one line will cause frequent snowmen to be built in the grate cooler and affect the normal operation of the kiln.

2. There are more clinker flying sand or large amount of liquid phase.

For the pre-calcination kiln, if the calcination temperature is too high, it is easy to increase the clinker dust, that is, there are many flying sand materials. At this time, the cooling efficiency is low and the dust cycle is intensified. "Snowmen. Excessive temperature or an increase in low melting point alkali components will also cause too much liquid phase. Excessive liquid phase combined with too much clinker dust, forming a floating layer, although The grate plate reciprocates as usual, but the material cannot be pushed away. As the material in the kiln keeps falling, the snowman of the grate cooler is inevitable.

3. Improper operation of barn bed structure and large kiln

The structure of the grate bed of the grate cooler is unreasonable, the operation is unreasonable, the clinker is not uniformly agglomerated, and the improper control of the cooler operation is also the cause of the "snowman".

4. Improper raw material ingredients

A large number of production practices have proven that the improper ingredients caused the flying sand phenomenon is the more fundamental cause of the snowman in the caster cooler.

5.Secondary combustion of incompletely burned pulverized coal particles occurs

A large number of production practices have shown that the "snowman" phenomenon occurs. "Flying sand" is the foundation, and the secondary combustion of pulverized coal is the key. In the case of flying sand, in order to strengthen the calcination and increase the firing temperature, the amount of pulverized coal is generally increased. Due to the excessive amount of pulverized coal, it is easy to cause the pulverized coal to be burnt impermeable and wrapped in clinker. In the case of uneven fly ash clinker production, some unburned pulverized coal enters the cooler along with the clinker, and is affected by the fine kiln "fly blast" clinker under the influence of large kiln rotation and high-speed air flow. Large clinker particles are segregated, and the caster plate stacked on the front of the caster cooler. Due to the high air temperature and sufficient oxygen content in the cooler, the incompletely burned pulverized coal particles undergo secondary combustion, resulting in fine-grained clinker. The secondary high temperature and liquid phase appear on the surface. At the same time, due to the poor ventilation rate between the fine particles, the caster fan is not easy to blow through, and the fine particles cannot be cooled as soon as possible, which causes the clinker to adhere to the front castor plate, resulting in a snowman.

6. Channeling raw materials will also form a pile of "snowman" phenomenon.

The channeled raw materials contain a considerable part of unburned coal powder, which will also cause the separation of small particles. Due to the high oxygen density and high temperature in the caster cooler, The secondary combustion occurs, so that the clinker continues to react in the caster cooler, resulting in a liquid phase on the surface of the fine clinker or the clinker particles that have been burnt through, and the phenomenon of "snowman" when the fan cannot blow through The situation may be: the high temperature zone moves forward excessively, the secondary air temperature is too high, and the material at the front of the caster cooler is not discharged in time with the negligence during operation. In the case where the clinker has not completely lost the liquid phase, Some parts are sticky, which makes the materials pile up naturally, forming a loose "snowman".


 

III. The reasons for the formation of flying sand are as follows:


1. The transition zone is too long: mainly the material stays too long in the range of 900-1250 degrees, which reduces the surface activity of the material. When bored into the high temperature zone, the amount of liquid phase is small and the material is not easy to form particles.

2, improper ingredients, n rate is too high.

3. Low liquid viscosity and low surface tension of materials.

4. Castor cooler operation (mainly a section of front fan with large air volume and thin material layer, blowing up the material).

5. Raw burn, under-burn, high crystalline silicon, etc., are easy to cause flying sand.

 

However, the main reason for decomposing kiln fly sand outside the kiln is that the excessive belt is too long, and the hollow kiln and preheater kiln are mainly caused by the high n rate.

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