Factors affecting the service life of air dust filter bags

A. Improper installation

If the filter bag is not paid attention to during the equipment installation process, improper operation can easily cause mechanical damage and failure of the filter bag.

1. The installation process is chaotic

During the installation of the filter bag of the pulse dust collector, the stacking of the bag cage and the filter bag was messy. The bag cage is deformed due to messy stacking and unreasonable operation. The deformed bag cage will directly affect the normal use and service life of the dust removal filter bag.

2. The filter bag is not vertical

The installation of the filter bag of the pulse bag filter requires that the bottom of the filter bag cannot touch any objects, including the bottom of the filter bag, even if the gap is too small, try to avoid it. Because the filter bag is not static during the continuous filtration and cleaning process, any object at the bottom of the filter bag will cause the filter bag to wear.

After the filter bag is installed, it is generally not vertical. If it is too skewed, it will cause long-term friction between the filter bag or between the filter bag and the wall, and the filter bag will wear out. To avoid such abrasion, the distance between the filter bag and the filter bag in the design of the dust collector should not be less than 1/2 of the diameter of the filter bag, and the distance between the filter bag and the side plate (beam) should be 1-2 of the diameter of the filter bag Times.

3. The filter bag is slack

The filter bag of the anti-air bag dust collector must have a certain degree of tension after installation. The top tension of each filter bag is 150-350N. At the same time, the filter bag is required to be tightened every time it is used (such as 3-6 months) once. If the filter bag is too slack, the bottom and middle of the filter bag will be damaged due to large deformation during the filtering-backflushing process.

B. The equipment is not well made

1. Rough processing of the bag cage

The rough processing of the bag cage is manifested by the rust of the bag cage, welding scars, burrs, open welding, etc., which will accelerate the mechanical wear of the filter bag, resulting in perforation, air leakage, and failure of the filter bag.

2. The flower plate is deformed

The flower plate of the bag filter is severely deformed and fails to meet the requirement of 2/1000 of flatness, and even has deflection and unevenness. The bag cage is directly installed on the flower plate. The deformation of the flower plate directly affects the stability of the bag cage relative to the flower plate. The verticality of the bag cage cannot be guaranteed, which will directly cause the bottom of the filter bag to directly collide with each other. Cause damage to the bottom of the dust filter bag.

At the same time, due to the deformation of the flower plate, the fit between the filter bag opening and the flower plate hole appears to be misaligned. First of all, the installation of the filter bag is difficult. Because the filter bag opening cannot be smoothly installed into the flower plate opening, it even appears to be stiff. The knocking situation will cause damage to the elastic ring in the filter bag mouth, and the installation and sealing of the filter bag mouth cannot be guaranteed, which will directly lead to the leakage of dust from the bag mouth, thereby causing air leakage and filter bag damage.

3. Deviation of flower plate hole

The hole diameter of the flower plate hole of the bag type Chen duster is greater than the deviation tolerance (0~+1). When the flower plate hole has a deviation of 2-3mm, the filter bag cannot be installed in place. If the flower plate hole has a negative tolerance, it will As a result, the filter bag opening will be knocked during installation, which will damage the bag opening and directly damage the filter bag.

3. The design is not fully considered

In the design process of the bag filter, various technical and economic indicators are often emphasized, and the rationality of the internal flow field and the service life of the filter bag are ignored, which causes the filter bag to be damaged.

1. The airflow rises too fast

The dust-containing airflow in the dust collector box rises too fast, which is an important cause of damage to the lower part of the filter bag.

2. High resistance of filter bag

The friction between the filter bag and the bag cage of the pulse bag filter often occurs as the filter-cleaning process proceeds, and the friction is not serious under normal resistance. If the parameters involved are incorrect, the impulse bag filter has poor dust removal and excessive resistance, the pressure difference between the inside and outside of the filter bag will increase, causing the filter cloth to withstand a rapid increase in filtration pressure, resulting in increased friction between the filter bag and the bag cage , Resulting in accelerated physical wear of the filter bag. This is because the friction between the two objects is proportional to the external force.

3. Air scour for cleaning dust

The main reason for the damage near the filter bag mouth of the pulse bag filter is that the filter bag is washed away by the cleaning jet airflow.

4. Unstable operating conditions

The actual operation of the bag filter cannot be in an ideal state all year round. The operating conditions deviating from the design parameters often occur, and the filter bag will be damaged at this time.

1. The temperature is unstable

High temperature seriously reduces the service life of the filter material and causes premature damage to the filter material. In addition to the temperature effect, sparks in the flue gas will often burn the filter bag. An effective preventive measure is to install a spark catcher to remove the sparks from the flue gas before delaying entering the bag filter.

2. Hydrolysis reaction

The hydrolysis reaction refers to the action of chemical substances reacting with water to cause self-decomposition and formation of new compounds. At present, the filter bag used in the bag filter is mainly chemical fiber filter material. Among them, the commonly used polyester filter media, polypropylene filter section and Nomex filter media are prone to hydrolysis reaction. For polyester, the common cause of damage is the hydrolysis of water vapor or the increase of water temperature, especially the hydrolysis attack in the alkaline environment.

3. Oxidation reaction

Oxidation reaction refers to the reaction of material molecules (or ions) losing electrons. This reaction increases the oxidation number of elements in the material. Among the chemical fiber filter materials, the easily oxidized filter materials include polypropylene and polyphenylene sulfide.

4. Acid-base reaction

Acid-base reaction here refers to the chemical reaction of the filter material when it meets acid and alkali. Various chemical filter media have a certain degree of tolerance to acid and alkali. But beyond a certain limit, its strength decreases and its lifespan is shortened. The influence of acids, alkalis and organic solvents in the flue gas on the life of the filter bag cannot be ignored.

Extending the service life of the bag filter bag is the common goal of design, manufacturing and management. Analyze the various reasons of filter bag breakage loss and take precautions against these reasons. It is very important for the stable operation of the bag filter, reducing operating costs and ensuring compliance with emission standards.