Analysis of common problems and maintenance of bag filter in asphalt mixing plant

25 Oct 2019 09:00
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In the production process of asphalt mixture, there are often some factors that affect the quality of its production. For example, the asphalt deduster at the asphalt commercial station will discharge emissions due to a large amount of high-temperature gas and dust, so the dust collector must be Proper and effective treatment can ensure its normal operation and meet emission requirements.

Bag filter has great advantages, such as strong adaptability, simple structure and stable operation, so it is widely used in the treatment of emissions.

However, the bag filter still has a large number of deficiencies, and it must be properly maintained to ensure its efficient operation.

I. Characteristics analysis, working principle and influencing factors of bag filter
The bag filter is a device used for effectively cleaning the emissions of the asphalt mixture during production. It is usually in bulk and has a combination of a base, a casing, an inlet and outlet chamber, a bag, and a pulse.

1, the characteristics of the bag filter.

China's transportation production industry often uses dust collectors, not only because of the independent production and longevity of the dust collector, but also its other advantages. The specific advantages are: one of the advantages of the bag filter is its dust removal efficiency. High, especially for the treatment of sub-micron dust, because its processing object is not very demanding, so the smoke content and dustiness have little effect on the dust collector, so the bag filter can be A wide range of applications.

In addition, the maintenance and repair work of the bag filter is simple and easy to operate.

2, the working principle of the bag filter.

The bag filter has a simple working principle, and the dust in the flue gas can usually be effectively treated by the self-contained bag. This treatment method has mechanical control, so the clean air is discharged while intercepting the dust. The intercepted dust is collected into the funnel and then discharged through the system piping.

The bag filter is easy to operate and easy to disassemble and maintain, so it is widely used in the treatment of organic waste gas treatment emissions.

3. Factors affecting the bag filter.

The bag filter has a limited service life, and in order to extend the life of the dust collector, it is necessary to eliminate the fault in time.

There are two factors that often affect the normal use of the bag filter, namely the frequency of dust cleaning and bag management.

The dust removal frequency will affect the service life of the bag filter. If the frequency is too high, the bag of the dust collector will be damaged. Usually, the filter bag of the dust collector should be coated with a filter bed to extend the service life of the filter bag.

Insufficient daily care of the bag will also affect the service life of the bag filter. Usually, certain precautions should be taken, such as preventing the bag from being wet, preventing the bag from being exposed to direct sunlight, and preventing the bag from deteriorating.

In addition, in the operation of the bag, the temperature of the exhaust smoke should reach the normal standard, and only in this way can the bag filter be operated efficiently and the service life can be prolonged.

Second, the bag filter is often used in the process of using the problem
1. The pressure difference in the bag is high but its dust removal ability is very low.

(1) Hydrocarbon pollutants remaining in the bag.

The source of the contaminated bag does not need to be determined at the first time, and the influencing factor is most likely a fuel problem. If the fuel in the bag is oil, it is prone to various problems, especially for heavy oil or waste oil. It is said that the viscosity of the oil is often increased because the temperature of the combustion is too low, and eventually the fuel cannot be fully burned, thereby contaminating the bag, causing a series of problems such as blockage and deterioration, which affect the service life of the bag. It is beneficial to improve the working efficiency of the bag filter.

(2) The cleaning of the bag is not enough.

In the usual dust removal work, the bag of the dust collector should be cleaned frequently to prevent the pressure difference from rising due to the cleaning failure. For example, in the initial setting, the normal pulse duration is 0.
25s, the normal pulse interval is 15s, and the normal air pressure should be controlled at 0.
5~0.
Between 6Mpa, the new system has three different pulse intervals of 10s, 15s or 20s.

However, because the cleaning of the bag is not in place, it will directly affect the pressure and cycle of the pulse, which will cause the bag to wear, shorten the service life of the bag filter, affect the normal production of the asphalt mixture, and reduce the efficiency and level of road construction.

2. Dust emissions will occur during the cleaning of the pulse in the bag.

(1) Excessive cleaning of the bag pulse.

Because the dust on the bag pulse is excessively cleaned, the dust particles on the surface of the bag are not easy to form, which affects the normal operation of the bag pulse, so that the pressure difference of the bag fluctuates, which reduces the service life of the bag filter and should be moderately reduced. The cleaning of the bag pulse ensures that the pressure difference is stable between 747 and 1245 Pa.

(2) The replacement of the cloth bag is not timely and the aging is serious.

The use period of the bag is limited, which may cause problems in the use of the bag due to various reasons, affecting the normal operation of the bag filter, such as excessive temperature, chemical corrosion, bag wear and the like.

The aging of the bag will directly affect the efficiency and quality of the discharge. Therefore, the bag must be inspected regularly, and the aging bag should be replaced in time to ensure the normal production of the bag filter and improve the quality of its work.

3. Corrosion of the bag.

(1) Chemical corrosion, such as sulfur in fuel, often occurs during the operation of the baghouse.

If the concentration of sulfur is too high, it will easily corrode into the bag of the dust collector, resulting in rapid aging of the bag, thus reducing the service life of the bag filter.

Therefore, it is necessary to control the temperature of the bag filter so as to effectively avoid the condensation of moisture therein, because the sulfur dioxide generated by the fuel during the combustion process and the condensed water form sulfuric acid, resulting in an increase in the concentration of sulfuric acid in the fuel.

It is also possible to directly use a fuel containing a low concentration of sulfur.

(2) The temperature of the bag filter is too low.

Because the bag filter will easily condense moisture when the temperature is too low, the formed moisture will cause the parts in the bag filter to rust, resulting in rapid aging of the dust collector, and at the same time, remaining in the bag filter. The chemical corrosion component becomes more intense due to the condensed moisture, which greatly damages the components of the baghouse and reduces the service life of the baghouse.

3. Maintaining the problems frequently encountered in the operation of the bag filter
1. Effectively treat hydrocarbon pollutants that often appear in bags.

Because the temperature of the fuel is too low, the fuel is not burned enough, and a large amount of hydrocarbon pollutants remain, which affects the normal operation of the bag filter. Therefore, the fuel should be properly preheated to a viscosity of 90 SSU or more. The low standard is followed by the next step of burning.

2. Deal with the problem of insufficient bag cleaning.

Due to insufficient cleaning of the bag, the pulse pressure and cycle of the bag are deviated. Therefore, the pulse interval can be reduced first. If the air pressure is to be increased, the air pressure should not exceed 10 MPa, thereby reducing the wear of the bag and prolonging the bag. Service life.

3. Dealing with the problem of excessive cleaning of the bag pulse.

Because the excessive cleaning pulse will affect the normal operation of the bag filter, it is necessary to reduce the number of times of cleaning the pulse, reduce the cleaning intensity, and ensure that the pressure difference of the pulse is controlled within the range of 747 to 1245 Pa, thereby reducing the dust of the bag pulse. emission.

4. Deal with the problem of aging of the bag in time.

Because the bag is easily affected by residual chemical contaminants, and the wear of the precipitator bag is accelerated due to excessive temperature during operation, the bag should be strictly inspected regularly, and replaced if necessary to ensure the dust collector. The bag is in normal operation.

5. Effectively control the concentration of the chemical constituents of the fuel in the bag.

If the concentration of the chemical component is too high, it will directly cause a large amount of corrosion to the bag, and accelerate the aging of the bag member. Therefore, it is necessary to effectively control the moisture condensation by avoiding an increase in the chemical concentration, and to operate by increasing the temperature of the bag filter.

6. Deal with the confusion of the differential pressure meter in the bag filter.

Because the pressure difference tube will often appear in the bag filter, in order to reduce leakage, it is necessary to protect the differential pressure pipe of the domestic sewage treatment device, and use a more robust and reliable differential pressure tube.

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