SU990311A1 - Device for cleaning gas from dust - Google Patents

Description

(54) METHOD FOR CLEANING GAS FROM DUST

The invention relates to air sanitation, purification of process and ventilation gases, and can be used in the power industry, as well as in other branches of the national economy, where gas cleaning is necessary. A known method for cleaning dust from gases is based on the ionization of dust particles and the introduction of filter material with an opposite charge into the stream of particles and subsequent separation of this material 1. The disadvantage of this method is that the gas stream must be cleaned in a cyclone where large dust is trapped and then in a bag filter to remove dust from small fractions, with dust particles co-coherent on the particles of the filter material can be separated from the latter due to the insignificant adhesive force. The aim of the invention is to increase the efficiency and cost-effectiveness of gas cleaning. The goal is achieved by trapping charged dust particles by depositing them on oppositely charged particles of filter material in a dust-gas flow, and the rate at which the filter material soars exceeds the rate at which particles are collected. The method is implemented as follows. A dusty stream of flue gases is passed through an ionizer, where particles (ashes) acquire, for example, a negative charge. Then, an oppositely charged filtering material is introduced into this flue gas stream, and the rate of growth of this material exceeds the rate of growth of particles to be collected. The dust particles under the action of electrical forces are attracted to the particles of filter material, are deposited on them and due to the fact that the speed of the soiling of the particles of filter material ensures their falling out of the stream, are removed from it along with the filter material. Example. Filtering material - slag granules, with a density of 2.5 g / cm, average copper size 3–10 mm, nominal 5 mm, winding speed 9–33 mm / s, nominal value 16 m / s, feed speed 2–2.5 m / c, rated speed 2.2 m / s.

Flue gas to be cleaned with ash particles from Kansk-Achinsk coal, density 2.2-2.4 g / cm, average median size 2-100 microns, nominal 25 microns, soaring speed 0.0002-0.40 m / s, nominal 0.08 m / s, feed speed of 1.2-1.7 m / s, nominal 1.5 m / s.

The efficiency of dust deposition on the filter material is 99.5-99.8%.

The cleaned gas is exhausted by the exhauster and exhausted into the atmosphere, and the captured filtering material enters the regeneration, where it is cleared of trapped dust, and then used again in the purification process.

The use of the proposed method for cleaning gases from dust provides in comparison with existing methods the following advantages: an increase in the efficiency of trapping, a reduction in the capital costs of the installation, and the elimination of additional gas purification after electrostatic coagulation of particles.

Increasing the degree of flue gas cleaning, for example, behind a 800 MW unit boiler, when burning Kansk-Achinsk coal, 98-99.5% reduces ash emissions by 0.34 t / h or 2300 t / g.

Claims (1)

Invention Formula A method of cleaning gas from dust, which includes ionizing dust particles and introducing oppositely charged filtering particles into the gas flow, characterized in that, in order to increase the efficiency and cost-effectiveness of gas cleaning, the introduced particles of filtering material impart a soaring speed less than the speed of their soaring, but more speed of dust particles. Sources of information taken into account in the examination 1. US Patent No. 4072477, cl. cl. B 03 C 3/01, 1978.