Influence of the charge of chromite-magnesite dust on the effectiveness of its removal in a bag filter

Abstract

The production operations of many industries, including the refractory industry, inciude drying, pulverizing of the raw material, transportation of the pulverized product, and other operations causing significant liberation of dust, which is removed by suction. The air removee by suction is cleaned in various dust collectors. The dust particles, as a rule, are charged (most frequently they possess charges of a single sign), and they characterize the total charge of the dust.Despite the fact that the literature notes the influence of the charge of the dust on its adhesion properties and the effectiveness of removal in dust collectors [i], very few concrete investigations in this direction are known.During filtering filter cloths, particularly synthetic ones, are capable of becoming strongly charged until the accumulation of high electrical potentials which may be the reason for the occurrence of fires in the filters. The influence of the charge of the cloths on filtering of dust also requires goal-directed investigations since they may reveal significant reserves for increasing the effectiveness of dust collection and reducing the energy consumption of the process.In investigations conducted earlier it was established [2] that in contact interactions of filter cloths with particles of mineral dusts a distribution of the electrical charges occurs with positive charges accumulating on the cloths and the particles falling from the cloth negatively charged. This is characteristic of industrial filtering of the air removed by suction.This article presents the results of work on determination of the effectiveness of filtering of chromite-magnesite dust with similar and different charging of the particles and the surface of the filter cloth.The laboratory investigations were made on an aerodynamic stand [3] which is a horizontal portion of a gas duct equipped with a dust generator, a fan, devices for fastening the filter bag, and instruments. The voltage of the electrical field created by the surfaces was selected as the characteristic parameter of the charge of the dust and the filter cloth~ The strength of the field was determined with E-ESP flux meters, the sensors of which were located in special closed openings located in front of the filter bag and behind it at a distance of i m and also above the bag at a distance of 0.I m from its surface. The effectiveness of dust removal was determined by the method of external filtering using the method of the State ScientificResearch Institute for the Industrial and Sanitary Cleaning of Gases [4].On the basis of investigations of the contact interactions of mineral dusts with polymer materials a device was developed for charging of a dust aerosol [5] which makes it possible to charge neutral and recharge positively charged particles to a negative polarity. The device includes a metal screen located perpendicularly to the direction of movement of the gas flow and a working element made in the form of dielectric strips located parallel to each other and to the direction of flow...

Protecting the environment. Investigating the electrostimulation process with fabric filtration

“…Also, industrial filtration of gases uses a lot of energy and consumes many filter materilas, which makes the process costly.Increasing the effectiveness of fabric filtration gives undoubted social and economic benefits.One of the most probable ways of doing this is to use electrostatic factors.The methods and results of the influence of electrostimulation are widely reflected in foreign publi-The positive influence of changing the dust using a friction effect on the efficiency of fabric filtration was noted in [4]. It is clear that the best result can be obtained by using an external electric field.…”