1. Overview of bag filter:
Generally speaking, the main structure of the bag filter has three boxes, the upper part, the middle part and the lower part, as well as the ash discharge mechanism and the return system.
The corresponding structures of the numbers are 1 upper box body, 2 blowing ash cleaning system, 3V type press, 4 middle box body, 5 control instrument, 6 lower box body, 7 ash discharge system. According to the different structure, there are many types. According to the filtering method, it can be divided into internal filter type and external filter type. According to the air inlet method, it can be divided into upper air inlet, lower air inlet, and direct current type. According to the shape of the filter bag, it can be divided into round and flat band. The dust removal principle of different types of bag filter dust collectors is basically the same. When the gas passes through the filter layer, the impurities and particles in the airflow remain in the filter layer to achieve the filtering effect.
2. Main points of installation and production of bag filter:
2.1. Support installation:
The production and installation of the support is the foundation of the bag filter. Generally speaking, the connection between the lower part of the foundation column and the embedded plate of the foundation is completed by welding. However, in the actual construction, the embedded plate connection error will appear when entering the site, so the verticality of the column should be adjusted during the actual installation, otherwise the frame size of the bag filter will not be able to correspond, and if the ribs under the column are in the factory It was installed before, which caused difficulties in installation. The solution can be to cut the ribs and columns by cutting, adjust the appropriate verticality, and then weld, and find the verticality and verticality by means of line inspection, level and tape measure.
2.2. Production and installation of ash bucket:
Dust will be concentrated in the ash hopper, so the ash hopper has important uses. Generally speaking, in order to reduce transportation costs and difficulties, the ash hopper is prefabricated in advance and then installed on site. Due to factors such as transportation and storage, the ash hopper may be deformed and increase the difficulty of installation. For its production and installation quality, the ash can be The bucket is divided into 2 sections, and the surrounding joints are staggered to ensure the installation quality.
2.3. Shell installation:
The shell mainly consists of side walls, top beams, columns and ring beams. Its installation will be restricted by the site. Generally, the bottom ring beam is pulled to the position of the support by hoisting, and then assembled into a body. Due to the volume of the shell It is very difficult to pull to a fixed position after installation on the ground. The installation of the flower plate requires air tightness. The punching method can be used to punch holes in the installation to avoid deformation of the flower plate. After installation, it needs to be checked for tightness.
2.4. Pulse valve installation:
After the impulse valve is installed, air leakage often occurs. The possible reasons are analyzed from practical work experience: gaps in the butt joint with the air bag, resulting in air leakage; the air bag structure itself has loopholes. The occurrence of these problems may cause the inside and outside of the spiral hole to be connected, causing air leakage. For this reason, in the installation of the impulse valve, the diameter of the gasket at the connection of the bubble and the impulse valve can be adjusted appropriately, and the bolt can be directly replaced, so that the installation quality can be improved.
2.5. Installation notes:
In the installation of the bag filter, welding and other operations must be carried out, which will generate dust and other problems. At the same time, there are quite a lot of temporary supports during the installation of the shell, so after the installation is completed, it is necessary to remove the temporary supports in time, remove the ash unloading valve under the ash hopper, and carefully clean the inside of the dust collector. After cleaning, install the ash unloading valve. Otherwise, it is prone to clogging of the ash unloading valve during installation, which will seriously affect the later use.
3. Analysis of factors affecting dust removal efficiency and life:
Its influencing factors can help us make reasonable model selection and improve the actual application effect. The main factors affecting its dust removal efficiency and life are:
(1) Filter bag material. The selection of filter bag material should be combined with the flue gas temperature. Currently, polyphenylene sulfide, polyphthalimide, polytetrafluoroethylene, etc. are widely used. Among them, polyphenylene sulfide has good acid resistance , Hydrolysis resistance, but the obvious disadvantage is that it is easy to age;
(2) Air-to-cloth ratio. The direct influencing factor of the dust removal efficiency of the bag filter is the air-to-cloth ratio, which is the area used for dust removal. However, increasing the air-to-cloth ratio will reduce the service life to a certain extent. Generally, when using compressed air pulse back blowing, the air-to-cloth ratio is set to 1.1~2.5m3/ (㎡miri-2, while when using purified flue gas back-blowing, the air-to-cloth ratio is 0.4~1.0m3/ (㎡miri -1) The flue gas with higher dust content can appropriately reduce the air-to-cloth ratio, and the actual dust removal efficiency, economic benefits, and site considerations should be comprehensively analyzed;
(3) Ash cleaning methods. Common cleaning methods include pulse air blowback, mechanical vibration and flue gas blowback. Generally, pulse air blowback is mainly used in bag filter with external collection structure of filter bag, the latter two It is mainly used in dust collectors for collecting dust in bags. The three cleaning methods have different damages to the bag filter. Relatively speaking, the latter two have less mechanical damage and will sing the service life of the bag filter.
Generally speaking, the main structure of the bag filter has three boxes, the upper part, the middle part and the lower part, as well as the ash discharge mechanism and the return system.
The corresponding structures of the numbers are 1 upper box body, 2 blowing ash cleaning system, 3V type press, 4 middle box body, 5 control instrument, 6 lower box body, 7 ash discharge system. According to the different structure, there are many types. According to the filtering method, it can be divided into internal filter type and external filter type. According to the air inlet method, it can be divided into upper air inlet, lower air inlet, and direct current type. According to the shape of the filter bag, it can be divided into round and flat band. The dust removal principle of different types of bag filter dust collectors is basically the same. When the gas passes through the filter layer, the impurities and particles in the airflow remain in the filter layer to achieve the filtering effect.
2. Main points of installation and production of bag filter:
2.1. Support installation:
The production and installation of the support is the foundation of the bag filter. Generally speaking, the connection between the lower part of the foundation column and the embedded plate of the foundation is completed by welding. However, in the actual construction, the embedded plate connection error will appear when entering the site, so the verticality of the column should be adjusted during the actual installation, otherwise the frame size of the bag filter will not be able to correspond, and if the ribs under the column are in the factory It was installed before, which caused difficulties in installation. The solution can be to cut the ribs and columns by cutting, adjust the appropriate verticality, and then weld, and find the verticality and verticality by means of line inspection, level and tape measure.
2.2. Production and installation of ash bucket:
Dust will be concentrated in the ash hopper, so the ash hopper has important uses. Generally speaking, in order to reduce transportation costs and difficulties, the ash hopper is prefabricated in advance and then installed on site. Due to factors such as transportation and storage, the ash hopper may be deformed and increase the difficulty of installation. For its production and installation quality, the ash can be The bucket is divided into 2 sections, and the surrounding joints are staggered to ensure the installation quality.
2.3. Shell installation:
The shell mainly consists of side walls, top beams, columns and ring beams. Its installation will be restricted by the site. Generally, the bottom ring beam is pulled to the position of the support by hoisting, and then assembled into a body. Due to the volume of the shell It is very difficult to pull to a fixed position after installation on the ground. The installation of the flower plate requires air tightness. The punching method can be used to punch holes in the installation to avoid deformation of the flower plate. After installation, it needs to be checked for tightness.
2.4. Pulse valve installation:
After the impulse valve is installed, air leakage often occurs. The possible reasons are analyzed from practical work experience: gaps in the butt joint with the air bag, resulting in air leakage; the air bag structure itself has loopholes. The occurrence of these problems may cause the inside and outside of the spiral hole to be connected, causing air leakage. For this reason, in the installation of the impulse valve, the diameter of the gasket at the connection of the bubble and the impulse valve can be adjusted appropriately, and the bolt can be directly replaced, so that the installation quality can be improved.
2.5. Installation notes:
In the installation of the bag filter, welding and other operations must be carried out, which will generate dust and other problems. At the same time, there are quite a lot of temporary supports during the installation of the shell, so after the installation is completed, it is necessary to remove the temporary supports in time, remove the ash unloading valve under the ash hopper, and carefully clean the inside of the dust collector. After cleaning, install the ash unloading valve. Otherwise, it is prone to clogging of the ash unloading valve during installation, which will seriously affect the later use.
3. Analysis of factors affecting dust removal efficiency and life:
Its influencing factors can help us make reasonable model selection and improve the actual application effect. The main factors affecting its dust removal efficiency and life are:
(1) Filter bag material. The selection of filter bag material should be combined with the flue gas temperature. Currently, polyphenylene sulfide, polyphthalimide, polytetrafluoroethylene, etc. are widely used. Among them, polyphenylene sulfide has good acid resistance , Hydrolysis resistance, but the obvious disadvantage is that it is easy to age;
(2) Air-to-cloth ratio. The direct influencing factor of the dust removal efficiency of the bag filter is the air-to-cloth ratio, which is the area used for dust removal. However, increasing the air-to-cloth ratio will reduce the service life to a certain extent. Generally, when using compressed air pulse back blowing, the air-to-cloth ratio is set to 1.1~2.5m3/ (㎡miri-2, while when using purified flue gas back-blowing, the air-to-cloth ratio is 0.4~1.0m3/ (㎡miri -1) The flue gas with higher dust content can appropriately reduce the air-to-cloth ratio, and the actual dust removal efficiency, economic benefits, and site considerations should be comprehensively analyzed;
(3) Ash cleaning methods. Common cleaning methods include pulse air blowback, mechanical vibration and flue gas blowback. Generally, pulse air blowback is mainly used in bag filter with external collection structure of filter bag, the latter two It is mainly used in dust collectors for collecting dust in bags. The three cleaning methods have different damages to the bag filter. Relatively speaking, the latter two have less mechanical damage and will sing the service life of the bag filter.
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