SU856563A1 - Method of electric cleaning of gases - Google Patents

Description

The invention relates to electric cleaning of gases and can be used in chemical, metallurgical and other industries for collecting particles of aerosol in a gas stream in high concentrations.

A known method of trapping aerosol particles in an electric field of a unipolar corona discharge during gas purification in electrostatic precipitators [Ί]. ¹

However, if the concentration of the aerosol at the inlet of the electrostatic precipitator exceeds a critical value, the gas cleaning efficiency is reduced due to the appearance of the effect of blocking the corona discharge current ·, which consists in a sharp decrease in the charge of particles and the operating current in the first streams of the electrostatic precipitator.

The purpose of the invention is the electrical cleaning of highly dusty gases.

This goal is achieved by the fact that aerosol particles are charged in the \ field of the bipolar corona (the presence of particles with charges of different signs leads to intense electrocoagulation and an increase in particle size), then they are deposited in the field of a unipolar corona discharge (particles are deposited much more efficiently due to the higher particle charge and the absence of the phenomenon of locking the corona due to a decrease in the total surface of the particles with an increase in their size).

The method is effective only when cleaning highly dusty gases, i.e. gases for which the following relation is fulfilled = 3-5, where the parameter of the dispersed phase is proportional to the space charge of particles at the input of the electrostatic precipitator, ^ η, αη ^{is the} parameter corresponding to the closure of the corona current.

The method is as follows.

Processing of highly dusty gas in the field of the bipolar corona is carried out directly by an electrostatic precipitator

81 or in the first field of the electrostatic precipitator. Dusty gas is supplied to a charger consisting of several rows of electrodes with a small radius of curvature (wires, needles), some of which are grounded, and high voltage is connected to the others. In this case, a corona discharge of different polarities appears on the electrodes, which is a source of positive and negative ₁₀ ions that charge aerosol particles. Then the dusty gas is directed into the field of the unipolar corona, where the particles precipitate.

Example. Gas hydrates after tower ₁₅ tation at 80 ° C and a concentration of 80-100 g / m * ® mist 40% phosphoric acid is fed into the charger. The residence time in the charger is 1-2 s. During this time, the mass of particles increases by 2-3 times. After the charging device, the coagulated aerosol particles enter the electrostatic precipitator, where they are deposited in the field of the unipolar corona.

Claims (1)

(54) ELECTRICAL CLEANING METHOD The invention relates to the electrical cleaning of gases and can be used in the chemical, metallurgical and other industries in the capture of aerosol particles present in high concentrations in the gas stream. There is a known method of trapping part of an aerosol in an electric field of a unipolar corona discharge when gas is cleaned in Til. However, if the aerosol concentration at the entrance to the electrostatic precipitator exceeds a critical value, the gas purification efficiency decreases due to the effect of corona discharge current blocking, which consists in a sharp decrease in the charge of particles and current in the first flows of the electrostatic filter. The purpose of the invention is to electrically clean highly dust-laden gases. The goal is achieved by the fact that aerosol particles are charged in the GASES field of the bipolar corona (the presence of particles with charges of different signs leads to intense electrocoagulation and an increase in the particle size), then they are precipitated in the field of unipolar corona discharge (particles precipitate much more efficiently due to the higher charge of particles and the absence of corona locking due to a decrease in the total surface of the particles with an increase in their size). The method is effective only when cleaning highly dust-laden gases, i.e. gases, for which the following ratio is taken. The method is carried out as follows. The treatment of highly dusty gas in the field of the bipolar corona is performed directly by the electrostatic precipitator 38 or in the first field of the electrostatic precipitator. Dust gas is fed to a charging device consisting of several rows of electrodes with a small radius of curvature (wires, needles), some of which are grounded, and others are connected to high zero. In this case, a corona discharge of different polarities arises at the electrodes, which is a source of positive and negative ions, which charge aerosol particles. Then the dusty gas is directed to the field of the unipolar corona where the particle is deposited. Example: Gas after a hydration tower with a temperature of 80 ° C and with a concentration of 80-100 g / m of 40% phosphoric acid mist is fed to a charging device. The residence time in the charging device is 1-2 s. During this time, the mass of particles increases by a factor of 2-3. After the charging device, the co-cooled aerosol particles enter the electrostatic precipitator, where they are precipitated in the field of the unipolar corona. Claims The method of electrical gas cleaning consists in charging and trapping aerosol particles in an electric field, characterized in that, in order to purify strong gases, aerosol particles are charged in the field of the bipolar corona, and then precipitated in the field of the unipolar corona. Sources of information taken into account during the examination 1. V.N. Uzhov. Cleaning industrial gases with electrostatic precipitators M. Khimi, 1967, p. 343.