Discussion on measures to protect kiln skin of rotary kilnDate: 2019-06-20 Views:
In dry cement rotary kiln, the service cycle of refractory directly affects the safe operation cycle of rotary kiln system, especially the service cycle of refractory brick in kiln. At present, most cement plants take the service cycle of kiln brick in kiln system as a overhaul cycle, and the most easily damaged part of kiln brick often occurs in the firing belt and transition zone, especially near the first wheel belt and the second gear belt. It is said that these parts should be more firmly protected by kiln skin, but because of the lack of experience, many new kiln operators can not protect the kiln skin well in operation, resulting in frequent accidents in these parts of red kiln.
Kiln skin is a sintered clinker layer attached to the inner surface of rotary kiln firing belt brick. After the clinker enters the firing zone, the liquid phase is formed, which is attached to the inner surface of the kiln brick and forms the kiln skin. The function of kiln skin first protects the fired kiln brick, which makes the kiln brick not directly contact with flame and high temperature material, reduces the damage to refractory brick caused by high temperature, chemical turbid and wear, and prolongs the service life of refractory brick. Secondly, the kiln skin plays the role of insulation layer, which can reduce the heat dissipation loss on the surface of the cylinder and improve the thermal efficiency of the kiln system. It can be seen that it is very important to protect the kiln skin to prolong the service life of refractory brick, but how can we have it in the operation of rotary kiln? Effective protection of kiln skin?
(1) first of all, hanging the kiln skin is the key.In the initial stage of feeding after overhaul and replacement of bricks, we must attach great importance to the operation of hanging kiln skin, and let experienced kiln operators do it as much as possible, so as to accurately control the temperature and clinker size in the kiln, adjust the appropriate raw meal composition, determine the reasonable feeding speed and rotating speed of the rotary kiln, and correctly adjust the flame shape and position of the coal injection pipe, so that the kiln skin can be hung for a suitable length, moderate thickness, strong and smooth. Uniform. There is no tumor scab phenomenon.
(2) The premise of protecting the kiln skin is to ensure the stability of the thermal system,because each large temperature fluctuation in the kiln can cause different degrees of damage to the kiln skin, therefore, the temperature in the kiln is controlled, the temperature is correctly judged, the temperature in the kiln is avoided to be too high or too low, It is of vital importance to strengthen the predictability of operation, to prevent the occurrence of the phenomenon of burning or running raw materials, to find the correct operation parameters of the rotary kiln according to the experience, to sum up the best matching value of the wind and coal, to make the wind, coal, material and kiln speed reasonably matched, and to ensure the stability of the thermal system of the rotary kiln. so that the high-speed rotation rate of the kiln and the operation rate of the system are improved, the yield of the clinker is high, And the purpose of good quality and low coal consumption is achieved.
(3) During operation,careful observation and correct judgment shall be made to prevent the occurrence of the phenomenon of formation of the ring or egg. If the length of the kiln is found to be thick or there is light ring root, the treatment shall be adjusted in time to prevent the growth of the ring. After the ring is formed, the ventilation resistance in the kiln is increased, and the short flame shall be forced to damage the kiln skin. After the large egg in the kiln, it shall be carefully operated, so that the feeding amount shall be reduced, the kiln speed shall be reduced, and the large egg shall be transferred to the kiln in time, so as to prevent the kiln skin from being damaged after the residence time in the kiln is too long.
(4) Strengthen the coordination between the central control and the site,strengthen the operation of the fire and fire, reasonably adjust the coal injection pipe, keep the correct flame temperature and shape and position, avoid the high-temperature point to burn in one area, and the high-temperature part can not be excessively concentrated. Keep the flame lively, smooth, strong, short and medium, the temperature is suitable, the kiln skin should not be washed, the top fire is prevented from overburning, and the kiln skin is damaged. Strengthen the maintenance of the rotary kiln equipment, reduce the fault and stop, if the kiln is temporarily stopped, keep the heat preservation work, prevent the temperature in the kiln from falling too fast, close the air door of the kiln tail in time, and prevent the kiln skin from quenching or cold and heat.
(5) if the temperature change on the cylinder scanner is observed frequently,if it is found that the kiln skin is not good, measures should be taken to adjust the air, coal and material in time. Do frequent watch and adjustment, control firepower in the middle, strict prevention of low fire can not hang up, burn fire top fire. In order to realize high quality and high yield, we should keep in the middle and hang in the normal operation.
(6) according to the characteristics of the raw combustible materials in our factory,the reasonable batching scheme is determined, so that the batching scheme adapts to the calcination temperature and avoids the material formula from being too refractory and difficult to burn or easy to burn. At the same time, it is necessary to strengthen the preparation of raw meal and the pre-homogenization of raw combustion materials, and reduce the fluctuation of raw meal composition and fuel composition, so that the thermal system can be easy to control and stabilize, so as to achieve the purpose of stabilizing kiln skin and protecting kiln skin.
In a word, kiln skin plays an important role in the calcination process of cement rotary kiln clinker. Hanging kiln skin and protecting kiln skin play an important role in the long-term safe operation of rotary kiln and the achievement of high quality, high yield and low consumption. As long as we carefully observe and summarize in production, we can master the changing law of kiln skin in our factory, adjust the operation method in time, stabilize the situation in kiln, and make it in dynamic balance, so as to achieve the best operation state.