According to foreign experience, dust removal equipment has three different levels of choice: the first choice is dustproof, that is, like various diseases, prevention is always more cost-effective than treatment. For example, when loading and unloading materials and belt transfer, a flow cell can be greatly reduced. Dust, or soot generation and treatment; in the treatment of steel slag and other bulk materials, the use of local airtight, so that the generated dust, smoke in the circulation of its kinetic energy, the dust will naturally settle down. This kind of mechanical dustproof and dust removal is called unpowered dust removal in foreign countries. Most of the dust in most occasions is suitable for unpowered dust removal; at least the unpowered dust removal pretreatment should be used first.
The second is to assist with the use of water spray, or foam removal. On the one hand, the direct spray can make the dust particles wet, adhere to each other, agglomerate and grow up, and then it is easy to separate the atmosphere; on the other hand, for the relatively high temperature flue gas, direct spray can realize evaporative cooling and can be made with a small amount of water. Flue gas cooling, volume shrinkage, and speed reduction are also beneficial for dust removal. Past textbooks and design manuals say that dust removal is only suitable for dusts of more than 50 m, and the dust removal efficiency is only 40-70%. The practical experience proves that due to the advancement of the spray technology, the dust can be removed by the spray system by more than 10%, and the dust of more than 1?m can also be removed by 90-95%. For example, the tundish package and the steel slag treatment have achieved a high dust removal efficiency of 90-95% by spray dust removal.
Therefore, from the perspective of reducing emissions, saving energy and reducing costs, we must first consider the unpowered dust removal and direct spray dust removal. It is only necessary to consider the third option: ventilation and 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, first consider the electric dust removal with low energy consumption, and finally consider the bag filter. According to this idea, reflecting on the actual selection order of our current dust removal equipment, we can find some problems worthy of improvement: such as secondary dedusting of converter, dust removal of blast furnace tapping yard, dust removal of loading and unloading materials, etc., dust particles 80% or even 90% All of the above are more than 10?m, but in most of China, the use of ventilation and dust removal, and the use of bag filter, has solved the problem of emission reduction, but the operating costs are very high; the dust is also the dust when the converter LT method is unburned Most of them are coarse particles, but the inlet concentration of electrostatic precipitator is designed according to 70-100 g/standard mil, resulting in a large electric field and huge equipment. Of course, some electrostatic precipitators are unstable and are practical problems that must be solved.
