RU2347981C1 - Device for trapping dust and gas emissions of processing assemblies - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: present invention pertains to types of exhaust hoods over processing assemblies. The device has an exhaust hood with vertical walls, a suck in opening and a gas outlet nozzle. Along the perimeter of the exhaust hood, there are extra vertical walls and overheard surfaces, which form gas storage containers. The extra vertical walls are fitted on the outer side of the exhaust hood at a distance 0.25-0.60 of the corresponding size of the width or length of the suck in opening of the exhaust hood.

EFFECT: increased efficiency of trapping dust and gas emissions.

2 dwg

Description

The claimed invention relates to varieties of exhaust hoods over technological units and can be used in metallurgical and other industries.

In particular, the claimed invention can be used to trap and remove fugitive dust and gas emissions resulting from steelmaking in medium and large tonnage electric arc furnaces.

Dust and gas emissions formed during the operation of medium-tonnage and large-tonnage electric arc furnaces are usually diverted in two separate streams. Organized technological furnace gases are separately discharged from the sub-water working space of the furnace, unorganized dust and gas emissions are released separately, which are released through leaks in the furnace (for example, through electrode gaps during smelting and oxygen purging), as well as during furnace filling, when steel is drained and at other stages of the process swimming trunks. Fugitive emissions leave the furnace in the form of a vertical heat stream of dust and gas emissions, rising vertically under the influence of thermal pressure of hot gases.

The most well-known and frequently used devices for capturing fugitive emissions from electric arc furnaces are roof hoods installed in the roof structures of electric arc furnaces and connected by flues to a common gas capture and gas cleaning system of an electric arc furnace.

The closest to the claimed invention in terms of technical nature and the achieved result is a device selected for the prototype for collecting dust and gas emissions from an electric furnace (Shvets M.N., Stalinsky D.V. Capture of fugitive emissions from large-tonnage and medium-tonnage electric arc furnaces // Ecology and Industry. - 2006. - No. 1. - S.12-16), containing an exhaust hood with vertical walls, a suction aperture and a gas outlet.

Such a device has optimal dimensions of the suction aperture in terms of corresponding to the size of the fugitive emission stream at the level of the suction aperture of the exhaust hood, which ensures the maximum suction speed of the gas stream and efficient capture of fugitive dust and gas emissions from the electric furnace.

The claimed object and the prototype coincide with such essential features: both devices contain an exhaust hood with vertical walls, a suction opening and a gas outlet.

Analysis of the technical properties of the prototype, due to its features, shows that the achievement of the expected technical result is hindered by such reasons. When "volley" emissions from an electric furnace of fugitive flows of dust and gas emissions occurring during violations of technological modes of smelting, as well as due to "drafts" in the workshop, the vertical flow of fugitive emissions can shift in the horizontal plane beyond the dimensions of the suction opening of the exhaust hood and not be caught by it, which reduces the efficiency collecting dust and gas emissions by an exhaust umbrella.

The basis of the claimed invention is the task of creating such a device for collecting dust and gas emissions, the design of which due to improvements through the introduction of new elements will ensure the achievement of a technical result, which consists in increasing the efficiency of dust and gas capture.

The problem is solved due to the fact that in the device for collecting dust and gas emissions of technological units, which contains an exhaust hood with vertical walls, a suction opening and a gas outlet, in accordance with the invention, the exhaust hood around the perimeter is equipped with additional vertical walls and ceiling surfaces that form gas storage tanks while additional vertical walls are installed on the outside of the exhaust hood at a distance of 0.25-0.60 of the corresponding p zmera width or length of the suction opening of the canopy.

When using the claimed invention, the achievement of a technical result is achieved, which consists in increasing the efficiency of collecting dust and gas emissions.

Between the set of essential features of the claimed invention and the achieved technical result, there is such a causal relationship.

At the calculated technological modes of operation of the technological unit, fugitive emissions flows into the exhaust hood within the dimensions of its suction opening. The optimal dimensions of the suction opening of the exhaust hood provide the maximum concentrated suction velocity of the fugitive emissions flow, which ensures the maximum gas capture efficiency of the exhaust hood. The suction opening and the entire volume of the exhaust hood are free from any obstacles and therefore nothing prevents the capture and gas removal of heat flows of dust and gas emissions. The kinetic energy and the velocity of the heat flux of dust and gas emissions directed vertically upward coincide with the directions of gas capture and gas removal. Fugitive emissions displaced beyond the dimensions of the suction opening and not captured by the suction opening of the exhaust hood fall into the gas storage tanks, accumulate in them, gradually descend, are sucked into the suction opening of the exhaust hood, and, together with the main stream of trapped dust and gas emissions, are discharged to the exhaust gas.

The sizes of gas storage tanks are determined on the basis of observations and studies of the distribution and capture of dust and gas emissions from fugitive emissions of technological units.

The installation of additional vertical walls on the outside of the exhaust hood at a distance from its walls of less than 0.25 of the corresponding size (width or length) of the suction opening of the exhaust hood is not practical, since in this case fugitive emissions that are not captured by the suction opening of the exhaust hood and are displaced beyond its dimensions, do not completely fall into gas storage tanks. A part of these flows is shifted beyond the dimensions of gas storage tanks and ends up in the free space of industrial premises, which reduces the efficiency of dust and gas recovery by an exhaust hood.

The installation of additional vertical walls on the outside of the exhaust hood at a distance from its walls of more than 0.60 of the corresponding size (width or length) of the suction opening of the exhaust hood is impractical because fugitive emissions accumulating in gas storage tanks will not be fully absorbed into the suction the opening of the exhaust hood and from the side opposite the suction opening will partially go beyond the dimensions of the gas storage tanks and fall into the free volume of production GOVERNMENTAL space, which reduces the efficiency of trapping dust and gas extractor hood.

The essence of the claimed device for collecting dust and gas emissions of technological units is illustrated by drawings, which depict:

figure 1 - General view of the device located above the electric furnace;

figure 2 is a view of the device in plan.

The drawings indicate the following notation:

1 - vertical walls;

2 - suction opening;

3 - gas outlet pipe;

4 - gas storage tanks;

5 - additional vertical walls;

6 - ceiling surfaces;

7 - electric furnace;

8 - stream of fugitive dust and gas emissions;

"a" is the width of the suction opening;

"b" is the length of the suction opening;

"c" is the distance between the additional walls and the walls of the exhaust hood.

In a specific embodiment, the inventive device for collecting dust and gas emissions of technological units contains a rectangular exhaust umbrella consisting of four flat vertical walls 1 with a suction opening 2 open at the bottom above the technological unit, with a gas outlet 3 in the upper part.

Along the perimeter of the exhaust umbrella for the formation of gas storage tanks 4, on its outer side, additional vertical walls 5 and ceiling surfaces 6 are installed at a distance from the walls 1. Gas storage tanks 4 are formed on one side by the walls of the exhaust hood 1, on the other hand, by additional vertical walls 5, and in the upper part of the ceiling surfaces 6, which tightly close the formed gas storage tanks 4. Gas storage tanks 4 are not connected to the exhaust pipe 3 of the exhaust hood. Moreover, additional walls 5 are installed on the outer side of the exhaust hood at a distance "c" from the walls 1, and the distance "c" is 0.25-0.60 of the corresponding size of the width "a" or length "b" of the suction opening 2 of the exhaust hood.

To capture dust and gas emissions that are formed during the operation of, for example, a 30-ton electric furnace 7, the optimal dimensions of the suction opening 2 of the exhaust hood are: width "a" - 9.0 m, length "b" - 9.0 m. Such dimensions provide the maximum the concentrated rate of suction of the fugitive emissions stream 8 at all design melting conditions in the electric furnace 7, which ensures the maximum efficiency of gas capture by the exhaust hood. Additional walls 5 are located from the walls 1 of the exhaust hood at a distance of 3.0 m, which is 0.33 of the corresponding size of the width "a" and the length "b" of the suction opening 2 of the exhaust hood.

The inventive device for capturing emissions of technological units is as follows.

For all design modes of melting the electric furnace 7, the dust and gas emissions streams of fugitive emissions 8 enter the suction opening 2 of the exhaust hood and are discharged to the gas treatment through the exhaust pipe 3. In case of violations of technological regimes, "volley" dust and gas emissions and other deviations from the design conditions, part of the fugitive dust and gas emissions (beyond the dimensions of the suction aperture 2 and not captured by the exhaust umbrella) fills the gas storage tanks 4, which are formed by the vertical walls 1 of the exhaust umbrella, with additional vertical walls 5 and ceiling surfaces 6. Then from these gas storage tanks 4 dust and gas emissions gradually fall down, are sucked into the suction The opening 2 of the exhaust hood and the exhaust pipe 3 along with the main stream of captured dust and gas emissions are diverted to gas treatment.

Given the above, it can be argued that as a result of using the claimed invention, a technical result is achieved, which consists in increasing the efficiency of dust and gas recovery.

Claims (1)

A device for collecting dust and gas emissions of technological units, comprising an exhaust hood with vertical walls, a suction opening and a gas outlet, characterized in that the exhaust hood is equipped with additional vertical walls and ceiling surfaces that form gas storage tanks, with additional vertical walls mounted on the outside exhaust hood at a distance of 0.25-0.60 of the appropriate size of the width or length of the suction opening of the exhaust hood.

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