South Africa Grinding Mill
In the process of limestone grinding production, the South Africa Grinding Mill inevitably has some mechanical or technological reasons that cause the furnace fire to be suspended. In order to avoid the damage of the kiln skin caused by the fire at the kiln head and the large-scale change of temperature caused by ignition, the method of breaking down the furnace fire and feeding 23.5t/h coal at the kiln head to ensure the temperature in the kiln is generally adopted.
If the inventory of the South Africa Grinding Mill is less than 25 m (40 m full), the waste gas from the kiln tail will be used to provide heat source for the raw mill for production. The specific method is: Valve 3210 is fully open, and the opening of valve 3213 can be adjusted according to the inlet temperature of the South Africa Grinding Mill and the circulating material quantity in the South Africa Grinding Mill. If the inlet temperature is high and the circulating material quantity is large, valve 3213 will be opened a little larger, otherwise, it will be opened a little smaller, and its opening is generally 40% - 95%. The opening of the valve in front of the high temperature fan and the valve 3409 in front of the rear fan depends on the temperature and negative pressure at the outlet of the cylinder. The temperature at the outlet of the cylinder is controlled to be less than 380 ℃, C. The negative pressure at the barrel outlet shall be controlled between one 600 and one 900 PA. In general, the opening of the valve in front of the high temperature fan is about 10%, and the opening of 3409 is about 10% ~ 15%. If these two valves are opened too large, the air volume in the kiln will increase, which will increase the heat loss in the kiln, so that the kiln can not be well insulated. Most of the heat will be pumped into the flue gas chamber and preheater at the kiln end, so that the temperature there will increase, which is easy to produce crusts. If these two valves are opened too small and the ventilation in the kiln is insufficient, the combustion of coal at the kiln head will be affected. Valve 3407 shall be closed, and valve 3212 shall also be closed. Under the premise of ensuring the micro negative pressure (i.e. 20-50 PA) at the outlet of high-temperature fan, valve 3202 shall be opened as much as possible, preferably fully open, so as to let the hot air out of the kiln pass through the South Africa Grinding Mill and dry the materials in the opposite mill.
It needs to be pointed out that if the external temperature is low in winter, when the South Africa Grinding Mill is to be dried and ground, it can be turned from 3210% to 20% in advance. If it is too small, it cannot reach the purpose of drying and grinding. If it is too large, the materials in the mill will be taken away by the wind. The temperature of the kiln tail gas out of the humidification tower is controlled at about 270 ℃, which can be controlled by adjusting the water pump pressure in the humidification tower, while the air temperature to the inlet of the South Africa Grinding Mill is about 230 ℃. In this case, because the hot air volume of vertical mill operation is limited (the valve opening in front of high-temperature fan is limited), the air volume into the mill is less, the total air volume into the mill is less, and the total heat is less than that in normal conditions. Therefore, the feeding amount should be reduced accordingly. The normal feeding capacity is about 155 T / h, while only 130-140 T / h can be fed. The outlet temperature of the mill is also lower than that of the normal one, which is about 90-95 ℃, and now the outlet temperature is controlled at about 65-80 ℃. The normal pressure difference is about 5.3kpa, and the pressure difference control is about 4.7kpa. The current of the mill was 90-100a, now it is 81-93a. Under normal conditions, the negative pressure at the inlet is controlled between one 300 and one 500 PA, while at this time, the negative pressure at the inlet is between & hellip; 900 L (000 Pa.In this state, the air volume and temperature at the inlet of the mill are more stable than that in the hot blast furnace, so the operation of the South Africa Grinding Mill is much more stable than that in the hot blast furnace, which greatly reduces the vibration caused by the instability of the material layer in the mill due to the fluctuation of the inlet temperature. At the same time, it also reduces the probability of all parts in the mill being damaged by vibration, so as to ensure the long-term safe and stable operation of the mill. At this time, not only the feeding capacity of the South Africa Grinding Mill is stable, but also the hourly output of the crusher is higher than that of the hot blast furnace (the hourly output of the crusher is about 110 T / h). In this way, the chance of using hot blast furnace to run South Africa Grinding Mill is reduced as much as possible.