Gas cleaning by granular filters in refractory production

Abstract

A considerable source of atmospheric pollution, mainly from the drying drums in the production of refractories, is the preparation and treatment of large quantities of batch materials.The products emitted from the drums used for drying ame characterized by a large concentration of dust (up to 20 g/m3); there is a nonretrievahle loss of materials and a great damage to production and the installation of high-efficiency dust traps is required, The use of bag filters is not possihle in this case because of the high humidity of the gas and the possihility of sudden temporary increases in temperature.In some cases, electrostatic filters are not effective because of the high resistivity of the materials (e.g., in the case of magnesite according to the data in Ill, the specific resistivity is 3-10 ~3 ~-cm). The use of high-efficiency wet apparatus is not desirable because of the consequent slurry effluent.Taking these circumstances into account, the Zaporozhe Branch of the Scientific-Research Institute of Gas Purification and the Zaporozhe Refractory Plant have carried out some studies over several years to develop a highly effective dry system for purifying gas and returning the trapped material to production using a granular filter [2]. Cheap and easily available materials are used as the filtering baffles in the granular filters.Some design solutions for granular filters make it possible not only to achieve the ultimate achievable concentration (UAU) of emissions to the atmosphere but also, in specific cases, to change to a technology which utilizes the rejects of the components of the Batch as the granular charge, as in the present study.Such equipment also has major advantages over other known equipment for high-quality dry purification, since, when loaded with granular catalyst or sorbent, the gas can be freed of harmful carhon monoxide, fluorine and sulfur compounds, compounds of boron and arsenic, etc~ [3--7].