Wind separation designs in bag filter dust collector and maintenance

The bag filter can be divided into three modes: upper inlet, lower inlet and side inlet according to the air inlet mode.

First, the way of entering the wind

The dust-containing gas enters from above the filter bag and the lower part is discharged. The direction of dust deposition in dusty flue gas is the same as that of flue gas. The upper air bag filter has better effect in treating aerosols with more ultrafine dust (<3μm), and the resistance of the equipment is smaller, but more Block flower board, complex structure, it is not easy to adjust the tension of the filter bag, there is stagnant air in the ash bucket, easy to accumulate ash, there will be condensation of water vapor, and it is inconvenient to clean, so most bag filter designs do not use this method.

Second, the way to enter the wind

The dust-containing gas enters from the lower part of the tank and is discharged from the upper part. Due to the sudden spread of the airflow, the flow rate suddenly decreases. A part of the larger particles of dust are directly dropped into the ash bucket by gravity, and then the airflow is guided to the filter bag through the deflector, and a part of the large particle dust directly settles, thereby reducing the wear of the filter bag. The deposition of the dust particles on the filter bag prolongs the cleaning time interval, but when the cleaning method of the reverse blowing is adopted, the sedimentation direction of the dust-removed particles is opposite to the direction of the cleaning gas flow, hindering the sedimentation of the soot, and Will produce "secondary dust", affecting the cleaning effect.

Third, side air intake

The dust-containing gas enters the dust collector from the side of the box, and then passes through the side of the flue gas distribution device to evenly distribute the dust-containing gas. The large-diameter solid particles can be coarsely separated, but the filter is caused by the lateral impact of the air flow. The bag is worn and worn, and the service life is shortened.

The flexible application of the inlet and outlet ducts provides an effective method for airflow uniformity and filter bag protection of baghouses. As shown in Fig. 1, the dust-containing gas enters the inlet air duct through the air inlet of the dust collector. Since the lower part of the baffle connected to each sub-chamber on both sides of the air passage has a diameter leading to each compartment ash hopper, the gas enters each compartment ash hopper. The deflector is deflected by the deflector into the compartment where the filter bag is located, and the clean air is discharged from the outlet duct. Some large dust collectors are long, the airflow is unevenly distributed along the way, the working conditions of the filter bags in the front and rear sections are not uniform, and the load and wear of the front filter bags are also more serious. Therefore, in order to prolong the time interval of replacing the filter bags during maintenance, reduce Cost, the position of the front and rear filter bags should be changed at regular intervals, so that the filter bag is affected by the dusty gas impact and the filtration load as balanced as possible.

Figure 1 parallel in and out of the air duct

Figure 2 is optimized on the basis of Figure 1. As shown in the figure, a diagonal deflector is added to the inlet air duct, one slows the airflow velocity, which facilitates the separation of large particles, and the other makes the longitudinal distribution of the airflow more uniform. It reduces the generation of large eddy currents and reduces the “secondary dust”, thus reducing filter bag wear, improving dust removal efficiency, simplifying maintenance matters, and saving operation and maintenance costs.

Figure 2 Gradient inlet and outlet duct

The pulse bag type dust collector is designed for sub-chamber, and the off-line cleaning method can be adopted. When a gas chamber is used for cleaning, the valve of the chamber is closed in advance, the filtration is stopped, the “secondary dust” is effectively avoided, and the cleaning effect is enhanced; Open the valve and filter the dust. The next unit goes into the cleaning mode, and so on.

Since the advent of the bag filter, it has been continuously optimized in the process of use at home and abroad. The air volume is from several hundred m3/h to millions of m3/h, and the dust removal efficiency can be as high as 99.9%. Shanghai Lingjin Environmental Technology Co., Ltd. specializes in technical consultation, scheme design, production and installation, operation and maintenance of bag filter for many years. While accumulating experience, it is also improving as the bag filter is continuously improved. As well as self-improvement to become a first-class environmental protection company, we are confident that we can do more for the environmental protection cause.