In recent years, with the rapid development of the economy, metallurgical steelmaking electric furnaces and boilers using raw coal as fuel have increased a lot. The atmospheric pollutants emitted by these kiln have caused great harm to the surrounding environment, so the particulate matter is removed from the dusty gas to reduce Its technology for emitting to the atmosphere is becoming more and more important.
　　 Bio-nano film
　　 The bio-nano film is a double ionosphere film with a layer spacing of nanometers, which can maximize the ductility of water molecules and has strong charge adsorption. The bio-nano film is sprayed on the surface of the material to attract and agglomerate small particles of dust. It is polymerized into large granular dust particles, and its self-weight increases and settles; the dust removal rate of bio-nano-film dust suppression technology is up to 99%, and the average operating cost is 0.05-0.5 yuan/ton. [1-2]
　　 Cloud dust suppression
　　 The cloud dust suppression technology is to produce ultra-fine dry mist of 1μm~100μm by high-pressure ion atomization and ultrasonic atomization; the ultra-fine dry mist particles are fine, fully increase the contact area with the dust particles, and the water mist particles collide with the dust particles and Coagulation, formation of agglomerates, agglomerates continue to become larger and heavier, until the final natural settling, to achieve the purpose of eliminating dust; the resulting dry mist particles, 30% ~ 40% of the particle size below 2.5μm, pollution of atmospheric fine particles The control effect is obvious.
　　 Wet dust collection
　　 The wet dust collection technology absorbs the air adhering to the dust by pressure drop, and removes dust under the double action of centrifugal force and mixing of water and dust gas; the unique design of the unique impeller can provide higher dust removal efficiency. [1-2]
　　 gravity
　　 The purification device that uses the principle that the specific gravity of the dust and the gas are different, so that the dust is naturally settled from the gas by its own gravity (gravity), is generally called a settling chamber or a descending chamber. It is a relatively primitive purification device with simple structure, large volume, low resistance, easy maintenance and low efficiency, and can only be used for rough purification. The working principle of the gravity dust chamber is as shown in the following figure: the dust-containing gas enters the sedimentation chamber from the side at a uniform velocity V in the horizontal direction, and the dust particles fall at the sedimentation velocity V sink. After running for t time, the dust particles are settled at the bottom of the chamber. The purified gas is discharged from the other side outlet.
　　 inertia
　　 Inertial dust collectors are also called inert dust collectors. Its principle is to separate the dust from the gas by utilizing the difference in inertial force between the dust and the gas during the movement. Generally, some form of obstacle is placed in front of the dusty airflow, causing the direction of the airflow to change drastically. At this time, the dust is much larger than the gas due to the inertial force, and the dust particles are separated from the air flow, and the purified gas is discharged after being sharply changed. The dust collector has a simple structure, low resistance (10-80 mm water column), low purification efficiency (40-80%), and is mostly used for the first stage of multi-stage purification, concentrating equipment in purification or cooperating with other purification equipment. use. Inertial dust collectors are most commonly used in louver. (It is suitable for purifying air containing non-tacky, non-fibrous dust, usually combined with other types of dust collectors to form a unit
　　 Cyclone separator
　　 Working principle: The dust-containing gas is introduced from the inlet between the outer casing of the precipitator and the exhaust pipe to form a rotating downward external swirling flow. The dust suspended in the external swirling flow moves to the wall under the action of centrifugal force, and goes to the lower part of the dust remover with the external swirling flow, and is discharged by the dust discharging hole. The purified gas forms an ascending internal swirl and is discharged through the exhaust pipe.
　　 Application range and characteristics: Cyclone dust collector is suitable for purifying non-sticky and non-fiber dry dust of more than 5~10 microns. It is a purification device with simple structure, convenient operation, high temperature resistance, low equipment cost and low resistance (80~160 mm water column). The cyclone dust collector is the most widely used in purification equipment.
　　 Cloth bag
　　 working principle:
　　 (1) Gravity sedimentation——When the dusty gas enters the bag filter, the dust with large particles and large specific gravity settles under the action of gravity, which is exactly the same as the sedimentation chamber.
　　 (2) Screening action—When the particle diameter of the dust is larger than the gap between the fibers of the filter material or the gap between the dust on the filter material, the dust is blocked when the airflow passes, which is called sieve filtration. This effect is more pronounced when there is an increase in dust accumulation on the filter material.
　　 (3) Inertia force action - When the airflow passes through the filter material, it can pass around the fiber, and the larger dust particles move in the original direction under the action of the inertial force, and the cockroach collides with the filter material to be caught.
　　 (4) Thermal motion - light and small dust (less than 1 micron), with the movement of the airflow, very close to the airflow streamline, can bypass the fiber. However, after being hit by gas molecules that are subjected to thermal motion (ie, Brownian motion), they change the original direction of motion, which increases the chance of dust and fiber contact, allowing the dust to be captured. The finer the diameter of the filter fiber, the smaller the void ratio and the higher the capture rate, so the more favorable the dust removal.
　　 Bag filters have long been used in various industrial sectors to capture unbonded, non-fibrous industrial dust and volatiles, and to capture dust particles up to 0.1 microns. However, when it is used to treat gases containing water vapor, condensation should be avoided. The bag filter has a high purification efficiency, and the efficiency of capturing fine dust is also more than 99%, and the efficiency ratio is high.