RU208397U1 - CYCLONE AFTERBURNING CHAMBER OF SMOKE GASES FOR DESTRUCTION OF PERSISTENT ORGANIC POLLUTANTS - Google Patents

Abstract

The utility model relates to methods and devices for the thermal treatment of toxic waste containing persistent organic pollutants (POPs). In particular, the present utility model is directed to a flue gas afterburning system in order to obtain environmentally friendly gas emissions. , an air supply pipe, and an outlet for flue gases located in the central upper part of the body, equipped with a hatch for removing solid particles and dust in the lower part of the body, an air jacket located outside the body, an outlet pipe, tangentially connected in the upper part of the body with a pipe for flue gas supply and a burner device tangentially connected in the lower part of the air jacket by a pipe for air supply, a cylindrical insert with a central channel having a tip located in the upper part of the cylindrical insert, while the burner placed in the pipe for supplying flue gases, a device with counter swirling flows is installed on the cover of the afterburning chamber, the central insert is not lined, but is made of heat- and chemical-resistant material, a flue gas swirler made of heat-resistant material, another cold air swirler is fixed to the tip at the top, located above, communicates with the cooling jacket, in the lower part of the cylindrical insert above the base there are arcuate cutouts for the exit of flue gases from the combustion chamber, the device with counter swirling flows is equipped with a dust collection hatch.

Description

The utility model relates to methods and devices for thermal neutralization of toxic waste containing persistent organic pollutants (hereinafter - POPs). In particular, the present utility model relates to a flue gas afterburning system in order to obtain environmentally friendly gas emissions.

The most widespread and accessible method of POPs destruction is fire neutralization, in the process of which thermo-neutralized inert material is formed, flue gases, ash and waste water from the gas cleaning system contaminated with POPs combustion products. The greatest danger to the environment is posed by the flue gases generated during combustion. For the complete decomposition of POPs, it is necessary to heat the flue gases to a temperature of at least 1200 ° C and hold at this temperature for at least 2 seconds. The probability of secondary catalytic synthesis of highly toxic dioxins and furans from decomposition products at a temperature of 300 ÷ 600 ° C has been experimentally shown. A sharp decrease in temperature and concentration of flue gases reduces the likelihood of secondary fusion. Modern regulatory documents allow the content of these substances at the exit from the thermal neutralization unit not more than 0.1 ng / m ³ .

Known installation for the afterburning of steam and gas emissions, containing a vertical cylindrical lined housing, located in it a combustion chamber, tangentially connected to it burner device, a pipe for supplying contaminated gases and an air supply pipe, an outlet for flue gases located in the central upper part of the body. (USSR author's certificate No. 1778447, publ. 30.11.1992). However, this installation does not have a cooling system for the combustion chamber, which leads to the need for a thicker lining layer and significantly burdens the installation due to the large mass of the lining.

The closest analogue of the proposed utility model is RF patent No. 2479791 publ. 04/20/2013, chosen by us for the prototype. A cyclonic chamber for afterburning flue gases, containing a vertical cylindrical lined body with a combustion chamber located in it, a burner device tangentially connected to it, a pipe for supplying contaminated gases, an air supply pipe, and an outlet for flue gases located in the central upper part of the body, equipped with a hatch for removing solid particles and dust in the lower part of the body, an air jacket located outside the body, an outlet pipe tangentially connected in the upper part of the body with a pipe for supplying flue gases and a burner device tangentially connected in the lower part of the air jacket with a pipe for supplying air, a cylindrical lined insert with a central channel connecting the lower part of the combustion chamber with the outlet pipe, and having an annular internal air cavity at the bottom connected with the lower part of the air jacket through metal channels, and at the top with the outlet pipe for removal flue gases, a truncated cone tip located in the upper part of the cylindrical insert, an ejector device formed by the inner surface of the outlet pipe and the outer surface of the tip, while the burner device is located in the flue gas supply pipe, and between the outer wall of the cylindrical insert and the inner an annular channel for tangential rotation of combusted flue gases is formed by the side surface of the housing.

In this design, as in the proposed one, a "dry" method of cooling flue gases by mixing with cooling air is implemented. The cyclonic afterburner is characterized by the fact that the outlet lined pipe is located in the center of the combustion chamber at temperatures above 1200 ° C. The role of the central insert in the cyclone is the need to change the direction of the gas flow to the opposite, and the main requirement for its material is heat resistance and resistance to acids and abrasives, which is provided by the lining. In this case, as is known, the temperature of the lined metal should not exceed ~ 0.3 melting temperature, at which the metal becomes ductile. A significant mass of a double-lined outlet pipe with metal cooling by a stream of air from unlined pipes passing through the combustion chamber turned out to be in a suspended state. This design does not provide the required structural, thermal and chemical resistance of the metal.

The disadvantages of the proposed technical solution include an ineffective method of mixing gas streams by ejecting cold air into a stream of flue gases, while the condensation nuclei formed during the mixing process can serve as a catalyst for the emission and transfer of dioxins to the gas cleaning system;

The technical result of the utility model is the possibility of more efficient cleaning of gases, i.e. increasing the efficiency of capturing small particles of ash, dust and condensation nuclei, which are sources of secondary catalytic synthesis of dioxins from decomposition products of POPs and carriers of dioxins, by combining a cyclone afterburner and a dust collecting device with counter swirling flows (CDF). Combination of the VZP device with a cyclone afterburner chamber also allows to reduce capital and operating costs due to the absence of additional gas ducts, a geometrically and functionally favorable combination of the cyclone outlet of the afterburner chamber and the inlet branch pipe of the VZP device.

The technical result is achieved due to:

- installation of a device with counter swirling flows (CDF) on the cover of the afterburner;

- giving the central cylindrical insert a simple geometric shape and making it from thermo- and chemically resistant materials;

- manufacture of a cylindrical insert from a heat-resistant material that does not need lining and cooling, which allows it to be installed on the lined base of the afterburner chamber and organize the rotation and exit of flue gases from the afterburner through slots in its lower part located in the afterburner; the upper part of the cylindrical insert outside the combustion chamber is used as an input element of the VZP device with a swirler of flue gases made of heat-resistant material and a rim-displacer installed on it;

- supplying a device with counter swirling flows with a hatch and a dust collection bin.

FIG. 1 shows the device of the proposed cyclone chamber for afterburning flue gases.

The cyclonic chamber for afterburning flue gases consists of a vertical cylindrical lined body 1, located inside the body, a central cylindrical insert 2 made of mineral thermo- and chemically resistant materials, a combustion chamber located between the body 1 and the central insert 2, an air jacket 10 located above the chamber a device with counter swirling flows (VZF), comprising a cylindrical lined body 19, a flue gas swirler 12 installed at the top of the central insert, a cold air swirler 11 communicating with the cavity of the cooling jacket 10, installed between the body 19 and the chimney 16, and a rim - displacer 13 tangentially connected in the upper part of the housing 1 of the branch pipe for supplying flue gases 6 and the burner device 5 tangentially connected in the lower part of the air jacket 10 of the branch pipe for supplying air 14.

In the lower part of the housing 19 of the VZP device there is a hatch 8 with a built-in branch pipe for evacuating dust from the dust collector 9 using a vacuum trap (not shown in the diagram).

The housing 1 in the lower part has a lined base 3 mounted on the supports 20 cooled by the jacket 10. In the lower part of the housing 1 of the afterburner there is a hatch 18 for removing solid particles and dust from the lower part of the combustion chamber. At the base 1, a branch pipe and a locking device 17 are provided for draining the salt melt. A central cylindrical insert 2 is installed on the base 3, which has arcuate slots 15 for the passage of flue gases from the combustion chamber into the cylindrical insert 2.

The thermal mode of operation of the afterburner, as in all heat-resistant lined systems, is continuous round-the-clock between preventive and current repairs.

The proposed cyclone chamber for afterburning flue gases operates as follows.

Flue gas from the combustion furnace through the branch pipe 6 is tangentially fed into the afterburner. An automatic burner is installed in the branch pipe 6, which provides a predetermined temperature in the afterburner when mixing flue gases from the furnace with the flue gases of the burner. Flue gases contaminated with organic matter that enter the burner torch decompose at high temperatures with the formation of simple low-toxic components (oxides of carbon, nitrogen, water vapor, hydrochloric acid and others, depending on the source material). m / sec, which ensures rotation and mixing of the gas flow in the cavity between the housing 1 and the central insert 2. Under the action of centrifugal forces, large suspended particles are thrown to the periphery, settle on the inner surface of the housing 1, and then settle on the base 3. Freed from suspended particles the flow of gases through the slots 15 is discharged into the central insert. The particles settled on the base 3 and the resulting molten salt are periodically evacuated through the shut-off device 17 or the branch pipe 18 into a vacuum trap.

The dust-laden gas enters the VZP device from below through the central insert, is twisted tangentially by the swirler 12 and moves from the bottom up along the axis of the apparatus, and dust particles are removed from the gas moving in a spiral. The countercurrent flow of cold air is supplied through the swirler 11 under pressure (not less than 0.3 MPa), rotating in the same tangential direction as the dusty gas, but in the opposite axial direction. In this case, dust particles move from the primary stream to the secondary. The secondary flow moves to the bunker 9 located behind the dusty gas inlet, changes its direction and transports the particles under the rim 13, where they settle in the bunker 9. The fine aerosol particles settled in the bunker 9 are periodically evacuated through the hatch 8 into a vacuum trap. Flue gases cleaned of fine dust are mixed with cold air and removed through chimney 16. The amount of air supplied for cooling is regulated by the temperature in the chimney from 16 to 300 ° C, which excludes the possibility of secondary synthesis of dioxins, because the synthesis of dioxins occurs at temperatures above 400 ° C.

Claims (1)

Cyclonic chamber for afterburning flue gases, containing a vertical cylindrical body with a combustion chamber located in it, and an outlet for flue gases located in the central upper part of the body, while the chamber is equipped with a hatch for removing solid particles and dust in the lower part of the body, an air jacket located outside the housing, an outlet pipe tangentially connected in the upper part of the housing with a flue gas supply pipe and a burner device, tangentially connected in the lower part of the air jacket with an air supply pipe, a cylindrical insert with a central channel, while the burner device is located in the supply pipe flue gases, characterized in that a device with counter swirling flows is installed on the cover of the afterburner, the central insert is not lined, but made of thermo- and chemically resistant material, a swirler of flue gases made of heat-resistant material is fixed at the top of the central insert la, another cold air swirler, located above, communicates with the cooling jacket, in the lower part of the cylindrical insert above the base there are arcuate cutouts for the exit of flue gases from the combustion chamber, the device with counter swirling flows is equipped with a dust collection hatch.

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