Factors affecting the adsorption of pulse dust collector
As the filtration time increases, more and more dust accumulates on the filter bag of the pulse dust collector, and the resistance of the filter bag increases, resulting in a gradual decrease in the processing air volume. In order for the pulse dust collector to work normally and control the resistance within a certain range, the filter bag must be cleaned. When cleaning dust, the pulse controller triggers the control valves in sequence, opens the pulse valve, and the compressed air in the air bag instantaneously sprays out into the filter bag through the pulse valve to the holes of the injection pipe. The dust attached to the surface of the filter bag falls off.
When the pulse bag filter is working normally, dust-laden gas enters the ash hopper from the air inlet. Due to the rapid expansion of the gas volume, some of the coarser dust particles fall into the ash hopper due to inertia or natural settlement, and most of the remaining dust particles follow. The airflow rises into the bag chamber. After being filtered by the filter bag, the dust particles are retained on the outside of the filter bag. The purified gas enters the upper box from the inside of the filter bag, and then is discharged into the atmosphere through the valve plate hole and the exhaust port. The purpose of dust removal.
As the filtration continues, the resistance of the dust collector also rises. When the resistance reaches a certain value, the ash cleaning controller issues a ash cleaning command. First, the lift valve plate is closed to cut off the filtered air flow; then, the ash cleaning controller pulses The solenoid valve sends out a signal, and as the pulse valve sends the high-pressure reverse airflow used for dust removal into the bag, the filter bag swells rapidly and produces strong shaking, which causes the dust on the outside of the filter bag to shake off and achieve the purpose of dust removal. Since the equipment is divided into several box areas, the above process is carried out on a box-by-box basis. When one box area is cleaning dust, the rest of the box areas are still working normally, ensuring the continuous and normal operation of the equipment. The key to the ability to handle high-concentration dust is that this strong cleaning method requires extremely short cleaning time.
The factors that affect the adsorption of the pulse dust collector are the nature of the adsorbent and the operating conditions. Only by understanding the factors that affect adsorption, can we choose suitable adsorbents and suitable operating conditions, so as to better complete the task of adsorption and separation.
1. Under normal circumstances, low-temperature operation is conducive to physical adsorption, and a proper increase in temperature is conducive to chemical adsorption. However, whether to raise or lower the temperature must be based on the adsorption melting during the adsorption process. If the melting becomes a positive value, increasing the temperature is beneficial to the adsorption operation; otherwise, lowering the temperature is beneficial to the adsorption process. The influence of temperature on gas phase adsorption is greater than that on liquid phase adsorption. For gas adsorption, pressure increase is conducive to adsorption, and pressure decrease is conducive to desorption.
2. The properties of the adsorbent, such as porosity, pore size, particle size, etc., affect the specific surface area, thereby affecting the adsorption effect. Generally speaking, the smaller the particle size of the adsorbent or the more developed the micropores, the greater the specific surface area and the greater the adsorption capacity. However, in the liquid phase adsorption process, the surface area provided by the micropores does not have a significant effect on the adsorbate with a large relative molecular mass.
3. The nature and concentration of the adsorbate have a certain influence on the gas phase adsorption. The equivalent diameter, relative molecular weight, boiling point and saturation of the adsorbate affect the adsorption capacity. If the same kind of activated carbon is used as an adsorbent, for organic substances with similar structures, the greater the relative molecular mass and unsaturation, the higher the boiling point, and the easier it is to be adsorbed. For liquid phase adsorption, the molecular polarity of the adsorbate, relative molecular weight, and solubility in the solvent affect the adsorption capacity. The greater the relative molecular mass, the stronger the polarity of the molecule, the lower the solubility, and the easier it is to be adsorbed. The higher the adsorbate concentration, the lower the adsorption capacity.
4. The activity of an adsorbent is an indicator of the adsorption capacity of the adsorbent, and it is often expressed as a percentage of the ratio of the mass of adsorption on the adsorbent to the total amount of adsorbent. Its physical meaning is the adsorption mass that can be absorbed by a unit of adsorbent.
5. Ensure that the adsorbent and the adsorbent have a certain contact time, so that the adsorption is close to equilibrium, and make full use of the adsorption capacity of the adsorbent. The time required for adsorption equilibrium depends on the adsorption rate, and the contact time is generally determined through economic trade-offs.
The performance of the adsorber of the pulse dust collector has a significant influence on the adsorption effect. The structure of the adsorber and the laying of the adsorption layer should be designed reasonably to ensure that the adsorber exerts its excellent adsorption performance.
Daily maintenance and dust removal of bag pulse dust collector
During the trial operation of the new bag filter, special attention should be paid to check the following points:
1) The direction of rotation, speed, bearing vibration and temperature of the fan.
2) Whether the disposal air volume and the pressure and temperature of each test point are consistent with the design.
3) The device status of the filter bag, whether there is any occurrence of bag drop, loose mouth, abrasion, etc. after use, can be judged by visual inspection of the discharge status of the chimney after it is put into operation.
4) Pay attention to whether there is condensation in the bag room and whether the ash discharge system is unblocked. Avoid infarction and corrosion attacks. When the fouling is serious, it will affect the efficiency of the host.
5) Adjustment of the cleaning cycle and cleaning time. This work is an important factor affecting the performance and operation of dust collection.
6) If the cleaning time is too long, the attached dust layer will be removed, which will be the cause of leakage and damage of the filter bag. If the dust removal time is too short and the dust on the filter bag has not yet been removed, the filter operation will be resumed. The resistance will quickly recover and gradually increase, which will ultimately affect the application effect. At the beginning of the operation, some unexpected conditions are often present, for example, abnormal temperature, pressure, moisture, etc. will cause damage to the new installation.
The test operation of the equipment directly affects whether it can be put into normal operation. If it is not handled properly, the bag filter may quickly lose its efficacy. Therefore, it is necessary to be careful and cautious to do a good job in the test operation of the equipment.
- Frequently check the operation status of control valves, pulse valves and timers, etc.
The failure of the impulse valve rubber diaphragm is a common phenomenon, which directly affects the cleaning effect. This equipment belongs to the external filter type, and the bag is equipped with a skeleton. It is necessary to check whether the parts fixing the filter bag are loose, whether the tension of the filter bag is appropriate, and whether the supporting frame is smooth to avoid abrasion of the filter bag. Compressed air is used for dust removal, so oil mist and water droplets need to be removed, and the oil-water separator must be cleaned frequently.
- Avoid condensation
During use, it is necessary to prevent the gas from cooling below the dew point in the bag chamber, especially when using the bag filter under negative pressure. Because the shell often leaks air, the air temperature in the bag room is lower than the dew point, and the filter bag will be damp, causing dust to adhere to the filter bag, blocking the fabric holes, resulting in a cleaning failure, and causing a pressure drop in the dust collector If it is too large, it cannot continue to operate, and some generate paste bags and cannot remove dust.
To avoid condensation, the temperature of the gas in the dust collector and its system must be 25～35℃ higher than the dew point (such as the dew point temperature of the kiln-grinding integrated machine is 58℃, and the operating temperature should be above 90℃) to ensure Good use effect of filter bag.