According to domestic and foreign dust removal experience, there are three different levels of dust removal equipment choices: the first choice is dust prevention, that is, like various diseases, prevention is always more cost-effective than treatment, such as adding a flow slot when loading and unloading materials and belt transfer, which can be large The amount of dust or soot generated and processed is reduced significantly. When processing loose materials such as steel slag, local sealing is adopted to allow the generated dust and soot to circulate and consume their kinetic energy, and most of the dust will settle naturally. This type of mechanical dust prevention and dust removal is called unpowered dust removal in foreign countries. In most cases, most of the dust is suitable for unpowered dust removal; at least first, unpowered dust removal pretreatment is required.
Second, the auxiliary use of water spray mist or foam dust. On the one hand, direct spray can make the dust particles adhere to each other, condense, grow up, and then be easily separated from the atmosphere. On the other hand, for relatively high temperature flue gas, direct spray can be used to achieve evaporative cooling. Flue gas cooling, volume shrinkage, and reduced speed are also conducive to dust removal. In the past, textbooks and design manuals stated that spray dust removal is only suitable for handling dust above 50 μm, and the dust removal efficiency is only 40-70%. Practical experience has proven that, due to the advancement of spray technology, dust can be removed by spray systems with a diameter of more than 10 μm close to 100%, and dust above 1 μm can also remove 90-95%. For example, the use of spray dust removal for tundish turning and steel slag treatment has actually achieved a high dust removal efficiency of 90-95%.
Therefore, from the perspective of reducing emissions, saving energy and reducing costs, we must first consider unpowered dust removal and direct spray dust removal. When we have to, we must consider the third option: ventilation dust removal. Because as long as you choose ventilation and dust removal, you must have high energy-consuming fans and dust collectors, it is more difficult to save energy and reduce costs. When using a ventilation and dust removal system, we must first consider electric dust removal with low energy consumption, and finally consider a bag dust collector . According to this thinking, reflecting on the actual selection order of our dust removal equipment, we can find some problems worth improving: such as converter secondary dust removal, blast furnace iron field dust removal, loading and unloading dust removal, and many other similar applications, dust particles 80%, or even more than 90% Both are more than 10? M, but almost all of our country adopts ventilation dust removal and bag dust collectors to solve the problem of reducing emissions, but the operating costs are high; the dust is also large when the LT method of the converter does not burn the dust. Some are coarse particles, but the inlet concentration of electrostatic precipitator is designed according to 70-100 g / m3, resulting in many electric fields and huge equipment. Of course, the unstable efficiency of some electrostatic precipitators is also a practical problem that must be solved.