The pulverized coal preparation system of the cement production line should be selected according to the process requirements of the kiln and the types of coal, coal quality and moisture. For the preparation of pulverized coal, a grinding system with drying should be used.
Cement production line pulverized coal preparation system design should meet the following requirements
(1) The position of the pulverized coal preparation system shall be determined according to the characteristics of the coal and the process layout requirements, and may be arranged near the kiln tail or the kiln head;
(2) The capacity of the raw coal bunker should meet the needs of coal mill production, the unloading should be smooth, and the feed equipment under the bin should use a quantitative feed scale;
(3) The capacity of the coal powder bin should meet the needs of the kiln production, and the coal powder bin should be unloaded smoothly;
(4) The coal feeding equipment, the dynamic pollinator returning pipe and the discharging part of the coal powder shall be provided with a wind lock device;
(5) All the ducts and rollers of the pulverized coal preparation system should reduce the turning, and when the turning is required, the pulverized coal should be prevented from accumulating;
(6) When using the spoke type grinding machine, the iron removal and metal detection alarm device shall be installed before the raw coal is put into the grinding;
(7) The process equipment and air duct of the pulverized coal preparation workshop shall be insulated;
(8) The external moisture of coal powder should not exceed 1.5%, and the fineness should be determined according to the coal quality and volatile matter content.
The safety and explosion-proof design of the coal powder preparation system of the cement production line shall comply with the following provisions.
(1) The coal mill, dust collector and coal powder bin shall be equipped with a pressure relief valve;
(2) The form of the pressure relief valve should be automatically opened and closed;
(3) The length of the short pipe before the pressure relief valve should not exceed 10 times the short pipe equivalent diameter;
(4) The short pipe before the pressure relief valve shall be straight pipe, and the angle with the horizontal plane shall not be less than 60;
(5) The area of the pressure relief valve on the inlet and outlet pipes of the mill shall not be less than the cross-sectional area of the pipeline;
(6) The calculation of the total area of the pressure relief valve on the pulverized coal storage bin shall comply with the relevant provisions of the current national standard “Guide for Dust Explosion Pressure Relief”) GB/T 15605;
(7) The pressure relief valve shall be provided with an inspection and maintenance platform;
(8) The temperature monitoring device shall be provided for the coal mill inlet and outlet; temperature and carbon monoxide monitoring and automatic alarm devices shall be provided on the coal powder bin and dust collector;
(9) The inlet and outlet pipes of the system dust collector shall be provided with a quick shut-off valve that is automatically closed in the power-off state;
(10) Gas fire extinguishing system shall be provided for coal mill, coal powder bin and coal mill dust collector;
(11) All process equipment, air ducts, coal powder silos and slides in the coal powder preparation workshop shall have grounding measures;
(12) Preparation of pulverized coal When using the residual heat of the firing system as the drying heat source, a dust-reducing facility should be installed before the human coal grinding.
The dust collection design of the coal powder preparation system of the cement production line shall meet the following requirements
(1) Dust collector equipment should use special dust collector for coal mill, dust collection equipment should have measures such as anti-combustion, explosion-proof and anti-static;
(2) The temperature of the gas entering the dust collector should be higher than the dew point temperature of 25.
In summary, the coal powder supply kiln and the decomposition furnace system should be separately equipped with a metering coal feeding device. Two pulverized coal bins should be set up, and a load cell should be provided. The pulverized coal conveying should be pneumatically conveyed.