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In order to avoid the occurrence of infarction in the new dry process cement clinker sintering system, the following measures can be taken:
(1) To ensure a balanced and stable operation. Otherwise, no matter how good the measures are, no matter how good the measures are, we can't guarantee that the system will not have the occurrence of the system infarction accident. For example, if the feeding amount in the system suddenly decreases, the excess heat in the high-temperature air flow will cause the raw meal temperature to rise abruptly, which may make the preheated raw meal sticky due to the increase of temperature, and form crust infarction. In addition, if the amount of carbonate in raw meal is smaller than the normal value, there will be surplus The heat (originally used for the synthesis of calcium carbonate) increases the temperature of the raw meal, which makes it sticky and causes skin infarction. On the contrary, if the amount of incoming material increases suddenly, it may directly lead to the blockage of local materials in the cone in the cyclone and affect the work of the whole system. Theoretical experience shows that most of the infarction accidents in practical consumption are caused by nonstandard design, nonstandard construction, abnormal operation and lax management, not all of which are caused by alkali circulation. For example, the brick falling from the refractory layer in the synthetic furnace and preheater, the failure of the air lock valve and the abnormal operation of the incoming material can lead to the occurrence of the infarction. The measures and key points on how to ensure the operation of "balance and stability" have been mentioned above and will not be repeated here.
(2) It is necessary to stop limiting the harmful components such as alkali, chlorine and sulfur in raw materials and fuels. The common requirements of suspension preheater kiln and external pre synthesis kiln for raw meal are alkali content (R2O) < 1.5%, chlorine content (CI) < 0.015%; the common request of suspension preheater kiln and synthesis kiln outside kiln for fuel is sulfur content in fuel (s) < 1.3%, and emphasizes that sulfur alkali ratio is close to 1 to prevent the use of coal with high ash content and low ash melting point. In addition, the alkali content in the raw material will not only lead to the crust and infarction of the system, but also reduce the quality of clinker.
(3) Application of air gun technology and regular cleaning. The air gun is equipped with high-pressure air. The device is installed in the equipment which is likely to have skin infarction, so that it can blow high-pressure air into the equipment at a certain frequency, so that it does not produce raw material crust conditions. Other secondary important * * are regularly blown and checked with compressed air, so as to ensure the stable and normal operation of the whole system.
(4) If some of the above conditions and measures cannot be met due to the limitation of objective conditions (for example, the content of alkali, chlorine and other harmful components in local raw materials is high), the bypass ventilation technology can also be used in the system flow, as shown in the figure below.
(5) In addition, previous cement workers have summed up an experience, that is, adding more raw material to the vertical cylinder of rotary kiln, which is blocked due to alkali accumulation, can reduce the level of crust and even eliminate the crust here.