With the increasing environmental protection requirements in our country, while introducing and renovating existing electric furnace smelting technology and equipment, the matching electric furnace dust removal system should also be considered. Let me introduce to you the characteristics of the electric furnace bag filter dust removal technology: 1. The dust removal uses a medium gas with adjustable pressure. In the initial stage of using bag filter material, its filtration efficiency is high, the degree of blockage in the dust removal bag is relatively light, and the pressure of the dust cleaning backwash can be controlled within 3-4kg. The electric furnace bag filter avoids premature fatigue of the dust bag due to long-term operation under high pressure; In the later stage of using the bag material, the degree of clogging of the dust removal bag becomes more and more moderate, and the operating load continues to increase. Low pressure back blowing is difficult to clean the dust. At this time, a pressure of 5-7kg can be used to clean the dust, so as to minimize the pressure drop of the filter and maintain a good cleaning effect, achieving the effect of extending the fatigue life of the bag. But at this time, a Venturi tube should be added to prevent high-pressure gas from blowing off and causing the bag to rupture. 2. The medium gas used for dust cleaning should be free of water and oil, and nitrogen is more ideal for steel mills. Because the compression control contains a certain amount of moisture under pressure and temperature. 3. After the dust collector stops running, it should continue to blow back and clean the dust for two cycles to avoid the combination of moisture in the air and dust on the surface of the bag from clumping and sticking to the bag. The main components of electric furnace flue gas include nitrogen, carbon dioxide, carbon monoxide, oxygen, as well as nitrogen oxides and sulfur oxides. Nitrogen oxides are produced by the high-temperature arc heating of nitrogen and oxygen in the furnace, while sulfur oxides are produced by some electric furnaces using heavy oil for combustion assistance. The temperature of the flue gas is very high, usually around 30 tons of electric furnace. The exhaust temperature at the furnace outlet is 1200-1400 degrees Celsius. If it is a high-power electric furnace, the flue gas temperature can reach 1600 degrees Celsius. The particle size of dust in electric furnaces is generally between 0.1 and 100 microns. These dust mainly include water, volatile substances, calcium oxide, magnesium oxide, iron oxide, iron oxide, aluminum oxide, tin oxide. The characteristics of electric furnace flue gas are small particle size, dust content, large flue gas volume, high temperature, combustible gases, and water vapor in the flue gas. At the same time, the dust has high iron content and has recycling value for box furnaces. One ton of dust will produce 12-18 kilograms of dust, and the gas will also contain dioxins, which seriously pollute the environment. When choosing a dust collector for this situation, it is generally necessary to first understand the main components and properties of the gas before selecting a suitable dust collector. Electrostatic precipitators may experience excessive resistance due to high furnace gas temperature, which seriously affects purification efficiency. Wet dust collectors, on the other hand, are prone to the presence of sulfides and nitrides, which can easily produce sulfuric acid and nitric acid, leading to severe corrosion of the equipment. Bag filter can capture a variety of sensitive dust, especially high specific resistance dust. Using bag filter is much more efficient than electrostatic precipitator, and the operation is very simple without producing sludge, corrosion and other problems. Add an activated carbon filter layer to reduce the concentration of PCDDs. When designing a dust removal system and selecting a dust collector, factors such as temperature and gas properties that have recycling value need to be considered. A suitable option is a bag filter, which is currently one of the most suitable choices. Bag filters have the advantage of purifying flue gas in that they can purify dust in the micrometer and submicron order, and even achieve high dust removal efficiency. The characteristics of bag filter: The steel industry has a large amount of dust and smoke emissions, with a variety of properties. There are three or four types of dust collectors used for dust and smoke control, including wet dust collectors, mechanical dust collectors, electrostatic precipitators, and bag filters. The electrostatic precipitator has a high efficiency, reaching 99.0% at 350 ℃, with low resistance of about 200Pa~300Pa, and a large processing air volume of over 106m3/h. It has been used in the steel industry, but due to its applicable specific resistance range of 104~1010 Ω. cm, it is greatly affected by changes in the physical and chemical properties of powder dust and cannot adapt to changes in process conditions and loads. The steel industry has a wide variety of dust and smoke types, with large changes in specific resistance. Many specific resistances exceed their applicable range, and some process conditions vary greatly, resulting in unstable dust removal efficiency. Therefore, it has been applied to this day due to various reasons.
