Film coating function:
1. Environmental protection and clean production
The filtration principle of the ordinary filter bag is deep filtration. During the filtration process, the dust particles penetrate deep into the filter media, gradually reducing the fiber gap of the filter media, and forming the initial layer of dust and the dust collecting layer on the surface of the filter media. The initial dust layer and dust-collecting layer established for a long period of time can achieve high dust-removal efficiency with ordinary filter materials. The filtering principle of the membrane filter bag is surface filtration, which can achieve effective filtration from the very beginning. The dust collection efficiency of the bag filter can reach over 99.99% from the beginning, the emission concentration is lower than 50mg/m3, and even lower than 10mg/ M3, to achieve smoke-free emissions, close to zero emissions. After China’s cement industry’s air pollution emission standards are in line with international standards, it is required that the dust emission concentration be lower than 50mg/m3, and that the film-covered filter bags are the most reliable first choice for cement mills.
2. Improve specific surface area and avoid excessive grinding
In the cement production process, the materials entering the raw material mill or the cement mill are all the components of different materials, such as the limestone raw material of the raw material system, the siliceous material and the iron raw material, etc., and then enter into the cement mill. Materials, gypsum, admixtures, and so on, various materials components are different in the difficulty of grinding, resulting in the degree of fine grinding with time (depending on the grinding speed) is not the same, the effective residence time in the mill In the process, some component materials quickly reached the fineness requirements of the grinding, but they had to continue to stay in the mill along with other components that were difficult to grind. The finer they were, the finer the grinding requirements were, With the increase of grinding temperature, the static electricity generated by these fine powders becomes stronger and stronger, which not only eases the impact of the grinding body, but also sticks the ball, pastes the liner, and reduces the grinding efficiency. This is the phenomenon of excessive grinding. Should be avoided as much as possible.
After the implementation of the new national cement standards, the fineness and specific surface area of the cement are required to be increased. Various companies adjust the process parameters such as grading of the grinding body in different degrees, and appropriately extend the standing time of the material in the grinding to determine the grinding time. The material is finer and the content of fine powder is more, and at the same time, the phenomenon of over grinding is more likely to occur. In order to avoid over-grinding, the wind speed in the mill must be increased, and the ventilation volume must be increased. The easy-to-grind materials should be promptly and quickly removed from the cylinder in advance. This work can be accomplished by a ventilation system. The resistance of the Omiya film-coated filter bags has been maintained at a relatively low constant range. The practice of long-term operation has proved that the ventilation and dust removal system composed of a film-covered filter bag dust collector and a fan greatly improves the ventilation volume and significantly improves the grinding rate. effectiveness. It can be said that the membrane filter bag has an irreplaceable role in improving the specific surface area and avoiding excessive grinding.
3. Adapt to large-scale equipment and high concentration of fine powder collection.
Large-scale equipment is a significant sign of technological progress in the modern cement industry. Not only does the stand-alone machine have high production capacity and good scale efficiency, but it also enables uniform material blending and stable production and quality. Selecting a large vertical mill in the new dry process production has become a representative of the advanced productivity of cement companies in China. The large-scale grinding process is inseparable from the large-scale high-density bag dust collectors. It is not only an environmental protection equipment for dust collection and management, but also a complete production equipment for fine powder collection. Ordinary filter bag due to the filtration mechanism is a deep filter, the filter bag will be quickly blocked in the high concentration of dust, the system resistance becomes very large, the service life of the filter bag is very short; and the coated filter bag due to its special filter Mechanism, dust will not enter the inner layer of the filter, the system’s resistance is always maintained at a very low level.