Practice of Industrial Dust Removal Technology in Cement Industry
Dust sources in cement industry
1) The grinding system is mainly responsible for the grinding of raw materials and cement. If the air flow velocity is inconsistent with the grinding fineness, grinding output and grinding ventilation, a large number of dust will appear. At the same time, human errors will lead to excessive dust.
2) During the drying process, the rotary drum keeps running continuously. During the continuous bumping process, the mineral aggregate and pulverized coal will be lifted and discharged from the airflow of the dryer.
3) In the process of cement production, a large amount of dust will be produced by crushing, and fine particles will also exist in the process of adding materials, causing dust pollution.
Application of dust removal technology in cement industry
Electrostatic Precipitation Technology
This technology plays an active role in dust removal in the cement industry, mainly because the dust removal efficiency can reach 99% at the initial stage, and the flue gas can be treated in a large range; It can well deal with the flue gas under various high-temperature environments, and the maximum temperature can reach 500 ℃. For example, the use of electrostatic precipitation technology in the cement kiln head can avoid the adverse effects of high temperatures; Keep continuous and automatic operation; The power consumption generated by the fan itself is less, and no large maintenance cost will be incurred. It cannot be ignored that the electrostatic precipitator technology also has certain shortcomings, which are shown in the large floor area, the influence of resistance on the dedusting efficiency is too large, the electrode deformation is easy to occur after long-term operation, and offline maintenance cannot be carried out. The specific use of electrostatic precipitation technology is mainly based on the four processes of gas ionization - dust charging - dust deposition - dust removal. In terms of dedusting at the kiln head, kiln tail, dryer and cement mill of the cement plant, the active use of electric dedusting technology can achieve good results, especially in the kiln head, because of its high temperature, the electric dedusting technology can play an effective role. At the same time, it is well integrated with the smoke dust specific resistance technology, and at the same time, humidifiers will be added, so as to better change the smoke dust specific resistance and improve the actual dedusting efficiency.
Bag type dust removal technology
The positive and effective application of the bag filter in the dust removal operation of the cement plant can also play a good role. Its advantage is that it has a very high dust removal efficiency, can effectively reduce the actual emission concentration of particles, and will not be negatively affected by the inlet dust concentration and specific resistance. It has strong performance stability, can adapt to a variety of load changes, and can achieve the goal of non-stop maintenance. The disadvantage is that it has a large operating resistance, the actual power consumption of the fan is high, and the filter bag itself can only be used for 3 to 4 years, with a high operating cost. In the process of using the bag type dust removal technology, first of all, make full use of the bag type filter element to filter and collect the dust in the gas to achieve the goal of purifying the gas. Secondly, it is necessary to play a full and reliable filtering role, and properly remove the dust on the surface of the filter bag, so as to promote the regeneration of the filter bag. As a dry high efficiency dust remover, the bag type dust remover has a strong filtering function and is well adapted to the current strict emission standards. The promotion effect is gradually obvious. At this stage, the cement industry can actively use kiln head, kiln tail and other aspects to achieve the goal of dust removal. The kiln head is mostly made of oxidation resistant needle punched felt fabric, 16 vertical bars are used as cages, and the fibers above 200 ℃ are used. At the same time, the resistance to acid and alkali gases and oxidation resistance should be well controlled; However, the kiln tail is mostly made of glass fiber PTFE coated fabric, and cage with more than 24 bars is used longitudinally. At the same time, TEFLON thread is also used for sewing to control the running resistance of the equipment itself.
Flue gas technology of dryer
In addition to the above two technologies, the dryer can also play a good role in dust removal. It should be noted that the smoke and dust after being processed by the dryer still has a high temperature, humidity and concentration after discharge, and most cyclone dust collectors cannot meet the requirements of environmental protection standards in the water sludge industry, and there are certain corrosion hazards. In order to effectively deal with this situation, the anti condensation glass fiber belt dust removal technology can be used in the drying link, so as to better control the dust content and improve the dust removal level of the cement plant.
The application practice of dedusting technology in the cement industry shows that both electrostatic precipitation technology and bag type dedusting technology can achieve good dedusting effect. They not only have high dedusting efficiency, but also show little difference in economic cost. In terms of dedusting concentration and emission reduction efficiency, bag type dedusting technology has strong optimization effect and can maintain a stable operating state. Compared with these two dedusting technologies, the dedusting method of the dryer shows obvious shortcomings. In general, in the future development of the cement industry, actively using the bag filter to carry out dedusting can give full play to the advantages and role of this technology.