RU1799284C - Wet gas cleaning device - Google Patents

Abstract

Usage: gas purification, in particular wet gas purification from suspended dust, Summary of the invention: a device for wet gas purification comprises a gas supply pipe arranged relative to a hemispherical screen to form an annular throttle gap between them, an initiator of gas-liquid flow oscillations, which is made in the form of an elastic annular a membrane located in the lower part of the gas supply pipe below the liquid level in a hemispherical screen and installed with the possibility of changing its frequency with the formation of a system for exciting vibrations of a gas-liquid medium in the screen, .2 silt,

Description

The invention relates to gas purification, in particular to wet gas purification from suspended dust, including containing fine particles up to 1 micron in size, as well as other impurities.

The aim of the invention is to increase the efficiency of gas purification from fine dust fractions by initiating acoustic waves in a gas-liquid medium.

In FIG. 1 shows a sectional apparatus for wet gas purification; Fig. 2 is a flow diagram of a gas-liquid medium in a screen.

The high-velocity gas supply through a thin gap between the membrane and the hemisphere with the liquid disperses the gas jet in the liquid and forms a finely dispersed gas-liquid system.

The supply of the gas supply pipe with an elastic annular membrane installed in its lower part, the placement of the membrane below the liquid level in the spherical screen, as well as the presence of an annular throttle gap between the gas supply pipe and the screen provides acoustic waves in the proposed device .. in a gas-liquid medium located in the cavity of a spherical screen, due to high-frequency oscillations of the membrane, under the action of a high-speed gas flow on the one hand, as well as the forces of elastic deformation of the membrane and the weight of the liquid column above the membrane, acting on the membrane on the other hand.

Since the oscillation frequency can reach 6–8 kHz or more, cavitation bubbles can also appear, which intensify the process of gas purification from fine dust fractions of 1 μm or less in size.

As hydrodynamic studies have shown, flows in the working volume, depending on the gas flow rate, are possible

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stable regimes with the formation of complex hydrodynamic flow patterns and the movement of the free surface of the liquid with gas bubbles.

Fig. 2 is a flow diagram of a gas-liquid medium obtained on a transparent model of the device by the light knife method.

In order to determine the local field of velocities of the liquid phase, a motion recording method of visualizing particles was used. During operation of the device, a toroidal vortex is observed with a velocity of 0.2–0.5 m / s on the periphery. The resulting vortex promotes a longer-lasting action of the cleaning liquid on the gas bubbles .. and prevents the pumping nozzle from splashing the liquid.

A feature of the system is also that the system has the property of self-adjusting the required volume of gas-liquid mixture in a spherical screen. When the unit returns to steady state, excess liquid is ejected. The required volume of gas-liquid mixture in a spherical screen depends on the gas flow rate and is 300-500 ml.

Acoustic waves in a gas-liquid medium cause intense vibrations of bubbles. The gas collapses until they collapse, which leads to a more intense capture of small dust particles by the liquid phase.

Acoustic waves also contribute to the coagulation of small particles into larger agglomerates, whose capture by the liquid phase is facilitated. The presence of bubbles of cavitation origin leads to reemission of waves and resonance phenomena, which intensifies the cleaning process.

Wave processes on the surface of a gas-liquid medium cause additional turbulization of the medium and lead to intensification of cleaning near this surface (Marangoni effect), while there is slight spraying (less than 0.005 kg of liquid per 1 kg of gas), which is an essential feature of the proposed device.

Studies have shown that particles larger than 5 μm are removed completely / completely, for particles 1-5 μm in size, the degree of purification is 94%, 1-0.5 μm is 70%

At the above gas flow rates, the flow rate of clean water for purification was 5 g per 1 m of polluted gas.

A device for wet gas purification includes a housing 1 With a supply pipe 2 and a gas discharge pipe 3, a supply pipe 4 and a washing liquid discharge pipe 5, concentrically mounted in the housing 1, made in the form of a concave hemisphere and a screen 6. filled with washing liquid and a drop eliminator 7 .

In the lower part of the gas supply pipe 2 below the liquid level, an elastic annular membrane 8 is installed, which is the initiator of the oscillations of the gas-liquid flow.

0 The gas supply pipe 2 is placed relative to the screen 6 with the formation of an annular throttle gap 9 between them.

To reduce the noise level during operation of the device, the gas supply pipe 2 and

5 screen b mounted on vibration mounts 10.11. A device for wet gas purification operates as follows.

Dusty gas is supplied to the gas supply pipe 2, having reached the surface of the spherical screen 6, the gas flow is rotated 90 ° and exits through the annular orifice 9 to the gap between the lower surface of the membrane 8 and the surface of the screen 6. By narrowing the gas flow cross section

5 in the area of the throttle gap 9 there is a sharp increase in its speed.

When moving to the throttle slit, the gas flow captures with itself the liquid, which is fed into the cavity of the spherical

0 screen b through the pipe 4 for supplying liquid, while mixing the gas stream with a clean liquid.

By acting on the lower part of the annular membrane, the resulting gas-liquid flow bends its edge from the surface of the spherical screen 6 and enters the cavity of the screen 6 above the membrane 8, and the elastic deformation forces of the membrane 8 and the liquid column located above it tend to compress

0 its edge to the surface of the screen b, as a result of which the elastic membrane 8 makes oscillatory movements, the frequency of which will be the higher, the higher the stiffness of the membrane 8 and the greater the gas flow rate.

5 The upper part of the working volume is made in the form of a hemisphere and plays the role of a droplet-breaker 7, which prevents droplet dropping of liquid from the device. . As tests have shown, the most effective value of the diameter of the upper hemisphere is 200-250 mm.

The excess fluid that flows through the pipe 4 into the cavity of the spherical screen 6 is poured over the edge of the screen 6 into

5 body cavity 1. In this case, particles transferred from the gas to the liquid are carried into the body cavity together with the liquid. The contaminated liquid is drained from the housing 1 through a flushing liquid discharge pipe 5.

The purified gas enters through the open part of the screen 6 and the droplet eliminator 7 into the gas outlet 3.

Tests were carried out on a prototype device, which had the following structural data: inner diameter of a hemispherical screen 140 mm, bore diameter of a thin-walled gas supply pipe 30 mm, membrane diameter 50 mm, membrane thickness 1 mm, membrane material - rubber, gap size in an annular throttle slots a 2-3 mm.

The device cleaned the contaminated gas containing dust fractions from 20 μm to 1 μm or less in size. The gas flow in the experiments was 10-15 l / s, the hydraulic resistance of the device was 150-280 mm water column.

The temperature of the inlet gas is 40 ° C, and the outlet gas is 20 ° C. To control the degree

gas purification device used an optical particle number counter.

Claims (1)

SUMMARY OF THE INVENTION A device for wet gas purification, comprising a housing, a gas supply nozzle, gas exhaust nozzles, inlet and outlet of washing liquid, concentrically mounted in the housing, a screen filled with washing liquid, made in 0 in the form of a concave hemisphere, and a droplet eliminator, so that in order to increase the efficiency of gas purification from fine fractions, it is equipped with an initiator of oscillations of the gas-liquid flow, 5 which is made in the form of an elastic annular membrane located in the lower part of the gas supply pipe, below the liquid level in the cavity of the screen, while the gas supply pipe is placed 0 in relation to the screen with the formation of an annular throttle gap. FIG. 2