Biological nano-film dust suppression technology, biological nano-film is a double-layer ionospheric film with nano-layer spacing, which can maximize the ductility of water molecules and has strong charge adsorption; Spraying biological nano-film on the surface of the material can attract and condense small particle dust, which will be polymerized into large particle dust, which will increase its own weight and settle; The highest dust removal rate of BME technology can reach above 99%, and the average operating cost is 0.05~0.5 yuan/ton.
Cloud dust suppression technology can produce ultra-fine dry fog of 1μm~ 100μm through high-pressure ion atomization and ultrasonic atomization. Ultra-fine dry mist particles are fine, which fully increases the contact area with dust particles, and the water mist particles collide with dust particles to form agglomerates, which become larger and heavier until they finally settle naturally, thus achieving the purpose of eliminating dust; 30%~40% of the generated dry fog particles are below 2.5μm, which has obvious prevention and control effect on atmospheric fine particle pollution.
Wet dust removal technology absorbs air with dust through pressure drop, and removes dust under the dual effects of centrifugal force and mixing of water and dust gas; Unique impeller and other key designs can provide higher dust removal efficiency.
Suitable for the production, processing, transportation, loading and unloading of bulk materials, such as mines, buildings, quarries, yards, ports, thermal power plants, steel plants, garbage recycling and other places. In the process of conveying, adding water and mixing the mixture, waste gas containing dust and water vapor will be produced. A large amount of dust, water, gas and waste gas are produced in the process of hot ore returning, which is the focus of treatment with high temperature, high humidity and high dust concentration. Because of the low temperature, the cold return process will not produce a lot of water vapor, but only dust-containing exhaust gas at the material transfer point.
The key to solve the waste gas treatment of mixing system is to use cold reflux process as much as possible. Wet dust removal should be adopted for the dust removal of the mixture system, and high-efficiency dust removal equipment such as pulse dust collector can be used for the dust removal equipment. (1) exhaust belt sintering machine is mainly used for dust removal of sintering machine tail gas and sintering of iron-containing raw materials. The waste gas produced by sintering machine mainly contains dust and harmful substances such as SO2 and NOX. For dust removal of waste gas from sintering machine, a water-sealed zipper machine can be installed outside the large flue, and the ash discharge pipes of the large flue, the ash discharge pipe of the dust collector and the small ash discharge pipe are inserted into the groove of the water-sealed zipper machine, and the ash is deposited in the water seal and then discharged by the zipper machine. Dust removal equipment generally adopts large cyclone dust collector and electrostatic precipitator.
(2) Treatment of sulfur dioxide in sintering machine flue gas
(1) The concentration of sulfur dioxide in sintering machine flue gas discharged from high chimney is generally 500 ~ 1000ml/m3, and the high concentration reaches 4000 ~ 7000ml/m3. This kind of waste gas has a large amount of emissions. If there are still some problems in the economy of recycling, most countries still give priority to high chimney emissions. According to the needs of sintering production, the chimney height is 100 ~ 120 m, but in order to protect the environment, many developed countries adopt higher chimneys, such as the highest chimney in the United States, 260m in Britain and 230m in Japan. At present, China Baotou Steel Sintering Plant uses low-sulfur raw materials for combustion, and sintering flue gas does not need desulfurization. After being discharged from a 200-meter-high chimney, the maximum ground concentration of SO2 is lower than 0.006mL/m3.
(2) The concentration of sulfur dioxide in the flue gas produced by the flue gas desulfurization sintering machine changes. The SO2 concentration in the head and tail flue gas is low, and the SO2 concentration in the middle flue gas is high. In order to reduce the scale of desulfurization unit, only sintering tail gas with high SO2 concentration can be introduced into desulfurization unit. The research on desulfurization of sintering machine in the world has entered the practical stage. For example, ammonia ammonium sulfate method, lime gypsum method and steel slag gypsum method in Japan; Lime gypsum method and magnesite recovery method in the former Soviet Union, and sodium sulfite method in China, etc. Figure 1 1-3 ammonium sulfate desulfurization process flow chart. This method uses ammonium sulfite solution as absorbent to generate ammonium bisulfite, which reacts with ammonia gas discharged from coke oven to generate ammonium sulfite. Ammonium sulfite is used as absorbent and then reacts with SO2. In this reciprocating reaction, the concentration of ammonium sulfite is getting higher and higher. After reaching a certain concentration, part of the solution is extracted, oxidized and concentrated into ammonium sulfate for recycling.
2, sintering machine tail dust removal
Dry dust removal is preferred for dust-bearing waste gas from the unloading point at the tail of sintering machine and adjacent sinter crushing, screening, storage and transportation, which can avoid sewage pollution caused by wet dust removal and is also beneficial to dust recycling. Large-scale centralized dust removal system is mostly used for dust removal of sintering machine tail gas. The tail adopts a large-capacity closed cover, which extends in the direction of the sintering machine, and all the trolleys at the upper part of the last few vacuum boxes are closed. Using the suction of vacuum box, the dusty waste gas in the closed hood is pumped out through the trolley material layer to reduce the dust removal gas at the tail. The dust removal equipment is preferably an electrostatic precipitator. Fig. 1 1-4 is the process flow chart of waste gas treatment of sintering machine. 3. Dust removal of the whole system
The whole particle system includes crushing and multistage screening of cold sinter, with many dust removal points and large air volume, so a special whole particle dust removal system must be set up. The system is equipped with centralized dust removal system, using dry high-efficiency dust removal equipment, generally using high-efficiency large airbag dust collector or electrostatic dust collector. (1) When the iron ore powder removed from the flue gas in the shaft furnace is mixed with additives such as lime, bentonite and coke powder for pelletizing, flue gas is generated during the shaft furnace roasting. Flue gas is mostly treated by dry dust removal, and the dust removal equipment can be bag filter or electrostatic precipitator. Cyclone dust collector and multi-tube dust collector can not meet the national emission standards and are not suitable for use. Figure 1 1-5 is the dust process flow chart of 8m3 pellet shaft furnace.
(2) No effective measures have been taken to control SO2 in the flue gas of pellet shaft furnace. The main treatment methods are preliminary desulfurization of high sulfur combustion and recovery of sulfur dioxide in flue gas. For example, Japan Iron and Steel Company uses (NH4)2SO3 as absorbent to absorb sulfur dioxide in waste gas, and then reacts with NH3 in coke oven gas to regenerate the absorption solution and return it to the sintering plant for reuse. Part of the absorption liquid is extracted and oxidized to prepare ammonium sulfate. In the United States, dolomite and other substances are added to the waste gas of sintering machine, and dust removal and sulfur dioxide are carried out by bag filter.