1 Filter bag pressure is too high
The high pressure difference of the filter bag can easily lead to the system’s ability to reduce dust, blockage of the ash pipeline, and the long-term operation of the fan under high-frequency conditions, which increases the energy consumption of the system.
The main reasons for the excessive pressure difference in the filter bag of the dust collector and the measures taken:
(1) The temperature of dust-containing gas is too high, and the system does not use any insulation and heat insulation measures, which makes the temperature difference between the dust in the pipeline and the dust collector and the external environment larger. During the heat exchange process, moisture vapor condensation occurs, and dust is added. Humidity and viscosity should be taken thermal insulation measures.
(2) Improper setting of relevant parameters of the pulse jet system and poor dust removal by the dust collector. For example, when the filter bag pulse injection time is too long, the pulse injection width is too short, and the compressed air pressure is too low, the filter bag becomes less open, and the dust on the filter bag is too thick. The pulse injection system related parameters should be reset.
(3) The filter bag material does not match with the dust characteristics, resulting in some air hole plugging. For large concentrations, small particle size, humidity and viscosity of the dust, film coating should be used.
(4) If the concentration of dust handled by the system is too high, the filtration speed of the filter material is too high, which will lead to high pressure drop of the filter bag. The dust removal load of the bag filter and the filter air velocity of the filter media should be appropriately reduced, that is, the filter area should be increased, and the filtering speed of the filter media should be reduced.
2 filter bag damage
As the dust on the surface of the filter bag wears, over time, the bag will appear “acupuncture” holes. Sometimes in the cleaning process, under the impact of strong winds under high pressure, the bag will also be damaged, resulting in an increase in the concentration of dust emitted from the gas. When the airflow containing more dust passes through the fan at high speed, it will cause the fan casing and Severe wear of the impeller. Take measures:
(1) Choose wear-resistant and corrosion-resistant filter bag materials to increase the service life of filter bags
(2) Regularly check the wear condition of the filter bag and find that the bag breakage phenomenon should be dealt with promptly. Small holes can be bonded and repaired, and large ones should be replaced.
3 Dust collector leakage
Generally, the dust collector is operated under negative pressure, and the air leakage can easily cause a large influx of outside air. The main performances of the dust removal are:
(1) Affect the stability of the kiln system. With the large amount of air that is leaking into the air, the effective air volume of the kiln system drawn by the exhaust fan is reduced, which affects the output.
(2) Drainage of equipment. Dust will be sprayed at high speed through the leakage point to the outside under the effect of cleaning power, causing workplace pollution.
(3) Increase operating resistance. The dust collector was originally operated at negative pressure, and the leaked air was positive pressure gas, which greatly increased the running resistance.
(4) Dew condensation inside equipment and equipment corrosion. A large amount of cold air enters the lowered operating temperature, especially in the cold winter and rainy seasons, resulting in paste bags, dew condensation, and equipment corrosion, affecting the normal use of the dust collector.
Therefore, necessary precautions must be taken to prevent air leakage.
(1) Strengthen the sealing of the equipment body. If the processing accuracy is improved, all the joints of the shell and the pipeline must be continuously welded. There must be no leakage and desoldering phenomena. The top manhole door must also be sealed to prevent the air leakage and leakage of the manhole door.
(2) Strengthen the sealing of other equipment of the dust collection system, such as equipment installed on site: rigid impeller feeders, inlet and outlet tuyere valves, conveying equipment and pipes, inspection doors, etc.
4 Poor gas source
The quality of the compressed air is the key to the stable operation of the pulse bag filter. The performance of the high pressure air affects the performance of the dust removal:
(1) High-pressure air supply. If the pulse valve work requirements cannot be met, the dust cannot be cleaned normally, resulting in a “padded bag”.
(2) High pressure wind pressure. At the moment of filter bag cleaning, only the pressure in the filter bag is more than 3-5 times the pressure outside the filter bag (negative pressure in the filter), so that the filter bag can be cleaned normally.
(3) High-pressure air must be kept dry and clean. The high-pressure air directly supplied by a general air compressor contains certain water and oil stains. If the water is not discharged in time, the moisture content will be blown into the filter bag with high-pressure air, which will inevitably cause a thick “porridge”-like dust on the surface of the filter bag. Layers, which lead to filter bag scrap. In addition, if compressed air contains a lot of oil and water, it can easily cause phenomena such as the accumulation of water in the cylinder, the leakage of the pulse valve, the reduction of the air pressure in the pneumatic triad, and the inability of the cylinder solenoid valve. A refrigerated gas dryer can be installed at the outlet of the air compressor, or a gas filter can replace the filter element in the dust collector gas tank, discharge water regularly and check the pressure difference of the gas filter when the pressure loss reaches 0 Change the filter element from .1 to 0.15MPa.
5 Impulse valve does not work properly
Impulse valves and controllers are not working properly, and they are directly expressed as “paste bags”, thereby increasing the system resistance and reducing the dust removal effect. Electromagnetic pulse valve leakage is the most common failure, the main reasons are:
(1) The pressure balance hole of the electromagnetic pulse valve is blocked. The installation of compressed air pipelines did not clean up foreign matter such as rust and welding slag inside the pipeline, or compressed air contained a lot of oil and water.
(2) The electromagnetic pulse valve diaphragm is damaged. All pulse valves of the precipitator do not work, the pressure of the air bag rapidly decreases to zero, the cylinder is closed, the pressure difference of the precipitator increases continuously, and the ventilation volume rapidly decreases.
When an electromagnetic pulse valve leaks, find the cause and take measures from the following aspects:
(1) Open the drain valve on the gas tank and blow it to remove foreign matter such as rust and welding slag inside the pipe.
(2) Replace the double diaphragm of the electromagnetic pulse valve. The diaphragm seals the compressed air of the pulse valve. If it is used for a long time, it will prone to aging and will not achieve sealing effect. When replacing, it is necessary to pay attention to whether the small holes on the grinding plate are breathable, and it is necessary to ensure the ventilation after installation.
(3) Replace the spring used to compress the diaphragm. Due to long-term, high-frequency use, the spring force will weaken, making it difficult to compress the diaphragm and cause air leakage.
(4) Replace the connecting spring of the electromagnetic pulse valve magnet. The spring is apt to rust, and after rusting, the elastic force is insufficient, so that the electromagnet cannot bounce after the electromagnetic pulse valve is de-energized, resulting in continuous air leakage of the electromagnetic pulse valve.
6 Abnormal operation of poppet valve
The abnormal work of the poppet valve is mainly manifested in:
(1) The valve plate comes off. The drop of the valve plate is mainly due to the position adjustment of the valve plate on the cylinder screw, and the valve plate is seriously deformed when the cylinder reaches the bottom dead center. Cracks occur around the center hole of the valve plate for a long time, causing the valve plate to come off. The treatment method is to increase the position of the valve plate upwards, so that when the cylinder is operated to bottom dead center, the valve plate will be slightly deformed (3 – 5 mm).
(2) The cylinder does not move or move in place. If the cylinder does not move, the exhaust port of the two-position five-way valve may be blocked or the interior of the two-position five-way valve may enter dust or foreign matter, causing the spool to fail to operate. Kerosene can be cleaned and used. Grease lubrication method to eliminate, in the cleaning must pay attention to the loss of internal gadgets, according to the method of demolition reversed. The failure of cylinder operation is mostly caused by internal cylinder failures, mainly due to the accumulation of water in the cylinder and the leakage of the cylinder piston. The accumulated water in the cylinder can be opened by sequentially opening the exhaust valve on the upper and lower top cover of the cylinder and the manual valve of the two-position and five-way valve to move the piston up and down several times to drain the accumulated water; when the piston leaks, open the cylinder Replace the seal on the piston.