RU2442828C2 - Device from capturing unorganized throwing-out from a metallurgic apparatus - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: the invention relates to metallurgy, in particular, to systems of capturing unorganized throwing-out from a metallurgic apparatus, such as electric arc furnaces. The device comprises a movable hood for capturing unorganized throwing-out, which has an outlet corresponding to the inlet of the gas duct fixed on the crane rail with the possibility to shut this duct, a fixed hood for capturing unorganized throwing-out, opening roof and metallurgic apparatus with inclining mechanism and control unit, pouring spout and a dust-collecting water-cooled chamber, which is connected pneumatically through the gas ducts with movable and fixed hoods, with an afterburner chamber, with water-cooled and non-cooled gas ducts and with a breeching. The dust-collecting water-cooled chamber is fitted with a heat exchange unit where its walls are made on the circle evolvent. Along the whole height of the chamber there are pipes for feeding and extraction of water positioned between the walls in layers, every pipe is connected hydraulically with risers installed vertically with the constant space angle in the heat exchange unit walls. Furthermore, the lower parts of risers are connected with radial-oriented pipes for heat carrier extraction.

EFFECT: improved dust and gas capturing with low water consumption and reduction of power consumption and labour cost in production of dust-collecting water-cooled chamber.

2 cl, 3 dwg

Description

The invention relates to the field of metallurgical production, in particular to systems for capturing fugitive emissions from metallurgical units, for example from electric arc furnaces.

A device for collecting gases from an electric arc furnace is known, comprising an exhaust umbrella located above the arched part and guide means made in the form of two full cones fixed to the arched part of the furnace, installed in accordance with a uniform gap at the base, the cones are different in height and the opening angle is different, the distance between the lower edges of the exhaust umbrella and the upper edges of the outer cone is 0.3-0.6 diameter of the furnace body, in which the inner cone is installed with a gap in the lower part around the perimeter above the arch furnace and is shifted towards the electrodes, and the space between the inner and outer cones at the level of the arch of the furnace has a lattice platform, while the opening angle of the inner cone is 60-90 °; the exhaust umbrella around the perimeter of the louvre insert and the outer cone also have heat-resistant elastic screens around the perimeter (RU, patent No. 2105933. C1. IPC ⁶ F26F 7/04, B08B 15/00. Device for trapping gases from an electric arc furnace / PI Kilin , K.P. Kilin (RU) .- Application No. 96106175/06; Stated March 28, 1996; Publish. February 27, 1998).

The disadvantages of the described device for trapping gases from an electric arc furnace - in relation to the problem we are solving - reducing pollutant emissions from technological equipment into the atmosphere and the surrounding area - are the low efficiency of the exhaust gases from electric arc furnaces and the utilization of carbon monoxide, nitrogen dioxide from the flue gas composition , sulfur dioxide, hydrogen fluoride, as well as dust from steelmaking slag from iron oxides, silicon oxide, magnesium oxide, calcium oxide, aluminum oxide, suspended s particles.

A device for collecting fugitive emissions from a metallurgical unit is known, comprising a crane with crane girders, a movable umbrella, the output of which is made in response to the entrance of a flue mounted on a crane girder with the possibility of overlapping it, a gas removal system with a pipe, chimney and filters, an opening arch and a tilt mechanism of the metallurgical unit with drives, a control panel and a casting trough, in which the device is equipped with an additional stationary umbrella mounted above the casting trough with a gas duct fixed to the crane beam, and also a trolley with a drive mounted on tracks fixed to the crane beams, while the movable umbrella is rigidly mounted on the trolley with the possibility of limited axial movement along the crane beams, the drives of the movable arch and the trolley are made with the possibility of synchronous movement and the flues of the mobile and stationary umbrellas are interconnected; it is equipped with an adjustable switchgear with a shutter, the inputs of which are connected to the gas ducts of the umbrellas, and the outlet is connected to the gas removal system, the shutter is located at the junction of the ducts and is configured to alternately close the duct of the stationary umbrella and partially overlap the movable umbrella, and the shutter drive is connected to the control panel of the unit with the possibility of synchronous operation with the tilt mechanism of the metallurgical unit; the trolley drive is made in the form of a rope system with a winch with a drive and a drum, placed on opposite sides of the movable umbrella along the crane beams, and the ends of the rope are fastened with an umbrella or trolley; it is equipped with an adjustable switchgear with a shutter, the inputs of which are connected to the gas ducts of the umbrellas, and the outlet is connected to the gas removal system, the shutter is located at the junction of the ducts and is configured to alternately close the duct of the stationary umbrella and partially overlap the movable umbrella, and the shutter drive is connected to the control panel of the unit with the possibility of synchronous operation with the tilt mechanism of the metallurgical unit; the damper drive is connected to the control panel of the metallurgical unit with the possibility of synchronous operation with the opening arch of the metallurgical unit; the gas ducts of the movable and stationary umbrellas are connected to each other at an acute angle, the valve is provided with an axis installed in the zone of connection of the gas ducts, and is made in the form of a cylindrical sector with the possibility of limited rotation around the axis; the end face of the movable umbrella exit and the end of the corresponding duct entrance is made at an angle of 30-60 ° relative to the horizontal axis, while the angle (γ) between the plane passing through the axis of the metallurgical unit at the level of the arch plane and the center of the duct entrance, and the plane passing along the end of the entrance is 80-90 °, moreover, the stationary umbrella is equipped with a visor installed in the opening between the movable and stationary umbrellas, the length of which is longer than the move of the movable umbrella (RU Patent No. 2282667, C1, IPC C21C 5/38 (2006.01). x emissions from the metallurgical unit (A.P. Fomenko, A.A. Zavratnov, A. B. Kryuk, G. I. Tomarev, M. V. Valitov, V. I. Ponomarev (RU). - Application No. 2005110494 / 02; Declared April 12, 2005; Published on August 27, 2006. - No. 24, 11. - Inventions. - Utility Models. - 2006. - No. 24).

The disadvantages of the described device for capturing fugitive emissions of a metallurgical unit include the fact that the collected gases from the metallurgical unit cannot be disposed of by direct discharges of gases into the atmosphere due to the large amount of solid particles and compounds in a gaseous form that poison the environment.

The essence of the claimed invention is as follows.

The problem to which the claimed invention is directed is to increase dust and gas collection from fugitive emissions of a metallurgical unit.

The technical result is a reduction in energy consumption for separating dust from a gas stream, for pumping cooling water from a heat exchanger and reducing labor costs for the production of a heat exchanger.

The specified technical result is achieved by the fact that in the known device for capturing fugitive emissions from a metallurgical unit containing a movable umbrella for fugitive emissions from a metallurgical unit containing a movable umbrella for fugitive emissions, the output of which is reciprocal to the input of a flue mounted on a crane beam with the possibility of overlapping it, stationary umbrella for fugitive emissions selection, opening arch and metallurgical unit with tilt mechanism and control panel, casting chute, water-cooled dust-precipitating chamber, pneumatically connected by gas ducts with mobile and stationary umbrellas, afterburning chamber, water-cooled and uncooled gas ducts, burs, equipped with remote-controlled valves and valves for automatic air intake, parallel mounted gas ducts, coupled to gas units, paired with gas units of which is connected by gas ducts to a gas exhaust pipe, according to the invention, the water-cooled dust separation chamber is provided and the heat exchanger, the walls of which are made according to the involute of the circle, pipelines for supplying and discharging cooling water are arranged in tiers along the height of the chamber between the walls, each of which is hydraulically connected to the risers installed vertically with a constant angular pitch in the walls of the heat exchanger, while the lower ends of the risers are connected to radially oriented pipelines for the removal of coolant; the live section of the flue duct of fugitive emissions of the metallurgical unit and the flow area between the walls of the heat exchanger are 1: (8 ... 20).

The invention is illustrated by drawings.

Figure 1 in a perspective view shows a device for capturing fugitive emissions of a metallurgical unit.

Figure 2 shows the camera dust precipitation cooled, horizontal section.

Figure 3 is a section aa in figure 2, a transverse vertical section of a chamber with a heat exchanger.

Information confirming the possibility of implementing the claimed invention are as follows.

A device for capturing fugitive emissions from a metallurgical unit contains a movable umbrella 1 for selecting fugitive emissions, the output 2 of the movable umbrella 1 is made in return to the entrance 3, mounted on a crane beam of the gas duct 4 with the possibility of overlapping it, a stationary umbrella 5 for taking fugitive emissions, an opening arch 6, metallurgical unit 7 with a tilt mechanism and a control panel, a casting groove 8, a water-cooled and a dust precipitation chamber 9. A water-cooled dust precipitation chamber 9 is pneumatically connected by gas ducts 4 and 10 with a mobile umbrella 1 and a stationary umbrella 5, a afterburner 11, a water-cooled gas duct 12. The hog 13 of an uncooled gas duct 14 is connected to a cooled gas duct 12. The hog 13 is connected in parallel to the gas ducts 15, 16 and 17 with blocks 18 and 19 gas purification.

The flues 15, 16 and 17 are equipped with valves 20, 21 and 22 of automatic suction of atmospheric air. The flues 16 and 17 have remote-controlled valves 23 and 24. The gas cleaning units 18 and 19 are connected by the flues 25 and 26 to the exhaust pipe 27 (FIG. 1).

The water-cooled dust-collecting chamber 9 (see FIGS. 2 and 3) is equipped with a heat exchanger 28. The walls 29 of the heat exchanger 28 are made according to the involute of the circle. Between the parts of the wall 29, pipelines 30, 31, 32, 33, 34, 35 and 36 are mounted tiered along the height of the chamber 9 for supplying and discharging cooling water. Each pipeline 30 (31-36) is hydraulically connected in series with risers 37, 43, 49, 55, 61, 67, 73, 79, 38, 44, 50, 56, 62, 68, 74, 80, 39, etc. . The risers 37-42, 43-48, 49-54, 55-60, 61-66, 67-72, 73-78, 79-84 are installed vertically in radial directions with a constant angular pitch in the walls 29 of the heat exchanger 28. The lower ends of the risers 37-42, 43-48, 49-54, 55-60, 61-66, 67-72, 73-78, 79-84 connected to the radially oriented horizontal pipelines 85-92. Pipelines 85, 86, 87 and 88 by taps 93-96 are connected to the right pipe 97 to drain superheated water. Pipelines 90, 91 and 92 by taps 97, 98, 99 are connected to the left pipe 100, to drain overheated water. In the radial pipe 89, chilled water is supplied, which along the risers 66, 65, 64, 63, 62 and 61 is sent to the horizontal pipes 30, 31, 32, 33, 34, 35 and 36.

To accelerate heat transfer and reduce hydraulic losses, the live section of the flue duct 4 of fugitive emissions of the metallurgical unit 7 and the flow area between adjacent walls 29 of the heat exchanger 28 are referred to as 1: (8 ... 20).

A device for collecting fugitive emissions from a metallurgical unit works as follows.

With the steady operation of the metallurgical unit, flue gases, combustion products, burnt dust, melting products caught by umbrellas 1 and 5, as well as afterburning products from the chamber 11 are sent to the dust precipitation water-cooled chamber 9 through the gas duct 4 in the direction from top to bottom. Due to the suction of fugitive emissions from the chamber 9 in a space bounded by risers 37, 43, 49, 55, 61, 67, 73, 79 and wall 29, a rotational movement is imparted to the gas stream. Due to the created centrifugal force field and gravitational forces, suspended particles of iron oxide (up to 22.9%), manganese oxide (4.2%), aluminum oxide (0.2%), zinc oxide (1.5%), copper oxide (0.2%), lead oxide (0.6%), chromium oxide (0.9%), calcium oxide (4.7%), magnesium oxide (2.9%) and other suspended solids (up to 61, 9%) along the wall 29 slide down to the base of the chamber 9. The walls 29 of the heat exchanger 28 and pipelines 30-36 are washed with a gas stream. The cooling water overheated in pipelines 30-36 enters the risers 55-60, 49-54, 43-48, 37-42, 79-84, 73-78, 67-72. Of these risers 55-60, 49-54, 43-48, 37-42, 79-84, 73-78, 67-72, through radial pipelines 85, 86, 87, 88 and 90, 91, 92 go to pipelines 93 , 94, 95 and 96 to the right pipe 97, and from the pipes 99, 98, 97 to the left 100 for cooling. In the heat exchanger 9, cooling water from the external water intake under pressure enters the radial pipe 89 from the radial pipe 89 through the risers 61, 62, 63, 64, 65 and 66, it enters the horizontal pipes 30-36. The hydraulic network of the heat exchanger 28 is constructed in such a way that superheated water flows unhindered into the drains 94, 95, 96, 97, 98, and 99, and then the left and right pipelines 97 and 100 are discharged for cooling. The gas stream moving between the walls 29 of the heat exchanger 28, moving along the branches of the spiral of the involute of the circle, enters the outlet of the chamber 9 into the cooled duct 12. From the duct 12, the gas flow through the duct 14 is directed to the bore 13. In the bore 13 the gas flow rate increases and the gas ducts 15, 16 and 17 are sent alternately to the gas cleaning units 18 and 19. In blocks 18 and 19, the separation of the dust fraction occurs. The cleaned gas stream through the flues 25 and 26 is sent to the pipe 27 for emissions of gases into the atmosphere.

Below is a calculation of pollutant emissions from technological equipment of the designed installation for the period of operation.

Emission source No. 0374 (projected) - electric furnace No. 6. During smelting, a large amount of dusty gases is released. The composition of the flue gas includes carbon monoxide, nitrogen dioxide, sulfur dioxide, hydrogen fluoride, as well as dust from steelmaking slag, hereinafter referred to as smelting dust. Melting dust consists of oxides of iron, silicon oxide, magnesium oxide, calcium oxide, aluminum oxide, suspended particles.

The reconstruction project of the chamber 9 provides for the removal of flue gases from the roof of the furnace during melting, as well as the removal of fugitive emissions from the electric furnace using a local roof suction installed above the electric furnace in the upper zone of the workshop. Fugitive emissions are connected to the process gases from the roof of the furnace and fed to the bag filters for cleaning, then with two smoke exhausters the furnace gases are discharged into the chimney 27 (emission source No. 0374 - projected).

Technical specifications for the process gas treatment system (according to OAO Giprogazoochistka).

Estimated gas purification capacity (total) ~ 342.5 m ³ / s.

The dust content of the gas at the outlet of the bag filters is not more than 20 mg / m ³ .

Steel smelting per year - 500 thousand tons / year of steel.

The operating mode of the DSP-6 furnace is 320 days for 24 hours (7680 h / year).

Process emission calculation

The qualitative composition of the smelting dust: iron oxides - 22.9%; manganese oxides - 4.2%; aluminum oxides - 0.2%; zinc oxides - 1.5%; copper oxides - 0.2%; lead oxides - 0.6%; chromium oxides - 0.9%; calcium oxides - 4.7%; magnesium oxides - 2.9%; others (for suspended solids) - 61.9%.

Given the identification of the composition of the emission, we obtain the following emission of dust into the atmosphere after cleaning in chamber 9:

melting dust - 6.85 g / s or 189.389 t / year, including; iron oxides - 6.85 * 0.229 = 1.56865 g / s or 43.370 t / year; manganese oxides - 6.85 * 0.042 = 0.2877 g / s or 7.9543 t / year; aluminum oxides - 6.85 * 0.002 = 0.0137 g / s or 0.3788 t / year; zinc oxides - 6.85 * 0.016 = 0.10275 g / s or 2.8408 t / year; copper oxides - 6.85 * 0.002 = 0.0137 g / s or 0.3788 t / year; lead oxides - 3.85 * 0.006 = 0.0411 g / s or 1.1363 t / year; chromium - 6.85 * 0.009 = 0.08165 g / s or 1.7045 t / year; calcium oxides 6.85 * 0.047 = 0.32195 g / s or 8.9013 t / year; magnesium oxides - 6.85 * 0.029 = 0.19865 g / s or 5.4923 t / year; other (for suspended solids) - 6.85 * 0.619 = 4.24015 g / s or 117.2317 t / year.

The ROUD company installs a afterburning chamber 11. In the afterburning chamber 11, carbon monoxide is burned to carbon dioxide. The afterburning efficiency of CO is approximately 95%. Therefore, the emission of gaseous substances into the atmosphere through the designed chimney will be: carbon monoxide - 16 kg / t * 560006 t / year * 0.05 = 40.0 t / year or 1.4468 g / s (taking into account the afterburner СО) ; nitrogen oxides - 0.27 kg / t * 500000 t / year = 135.0 t / year or 4.8828 g / s; sulfur dioxide - 1.6 g / t * 560006 t / year = 0.800 t / year or 0.0289 g / s; hydrogen fluoride - 0.56 g / t * 500000 t / year = 0.280 t / year or 0.0101 g / s. The total emissions of nitrogen oxides are divided into oxide and nitrogen dioxide:

During the filling of the furnace, during the melting of the furnace, when downloading slag and the release of metal, as well as in the process of melting from the furnace, fugitive emissions of pollutants into the workshop area take place. Approximately 80% of the above emissions are removed through a local suction installed in the upper zone above the furnace for gas purification (emission source No. 0374), the remaining 20% are discharged into the atmosphere through leaks in the fencing of the workshop (unorganized emission source No. 0375).

According to the “Handbook of specific indicators of atmospheric pollutants for some industries - the main sources of air pollution”, St. Petersburg, 1999, the specific indicator of fugitive emissions of pollutants entering the working area 1 of the furnace workshop is: carbon monoxide - 0 , 8 g / t of steel; nitrogen oxides - 5.3 g / t; sulfur dioxide - 1.75 g / t; hydrogen fluoride - 0.56 g / t.

Thus, the reconstruction of the chamber 9 will significantly reduce the energy consumption for dust separation from the gas stream, for the transfer of cooling water from the heat exchanger 28. The design of the heat exchanger 28 provides a significant reduction in material and labor costs for the production and operation of the chamber 9 due to the compact arrangement of pipelines 30-36 and risers 37-84 installed along the branches of the involute circle.

Claims (2)

1. A device for capturing fugitive emissions from a metallurgical unit, comprising a movable fugitive emission sampling umbrella, the output of which is provided in response to an input of fugitive emissions fixed to a crane girder with the possibility of overlapping it, a stationary fugitive emission sampling umbrella, an opening arch and a metallurgical unit with a tilt mechanism and remote control, casting trough, water-cooled dust-collecting chamber, hog, pneumatically connected by gas ducts with movable and stationary umbrellas, an afterburner and water-cooled and uncooled flues, equipped with remote-controlled valves and automatic air intake valves, parallel mounted flues coupled to gas purification units, each of which is connected by flues to a gas exhaust pipe, characterized in that the dehumidified chamber the heat exchanger, the walls of which are made according to the involute of the circle, pipelines for supply and discharge of cooling water, each of which is hydraulically connected to the risers installed vertically with a constant angular pitch in the walls of the heat exchanger, while the lower ends of the risers are connected to radially oriented pipelines for the removal of coolant. 2. The device according to claim 1, characterized in that the living cross-section of the flue gas duct of fugitive emissions of the metallurgical unit and the flow area between the walls of the heat exchanger are 1: (8 ... 20).

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