KR102316717B1 - Detoxification treatment apparatus of noxious gas using heat exchange - Google Patents

Abstract

Provided by the present invention is a detoxification apparatus for a harmful gas using heat exchange. The detoxification apparatus for a harmful gas using heat exchange, which is capable of improving heat exchange efficiency, comprises: an exhaust gas injection pipe into which an exhaust gas containing harmful substances is injected; a heat exchange pipe which is connected to the exhaust gas injection pipe so as to be in communication with the exhaust gas injection pipe, and in which the exhaust gas introduced from the exhaust gas injection pipe performs heat exchange while flowing such that the exhaust gas becomes harmless; a hollow casing in which the heat exchange pipe is disposed and a coolant flow path is formed so that a coolant flows; a coolant injection pipe disposed on one side of the casing so as to be in communication with the coolant flow path formed inside the casing and configured to inject a coolant into the coolant flow path; and a coolant discharge pipe disposed on the other side of the casing so as to be in communication with the coolant flow path formed inside the casing and configured to discharge a coolant that has been used to cool the heat exchange pipe to the outside of the casing.

Description

Hazardous gas detoxification treatment device using heat exchange

The present invention relates to an apparatus for detoxifying harmful gases using heat exchange, and more specifically, SAF (Submerged Arc Furnace) containing arsenic, a harmful component generated in the process of treating waste LEDs through high-temperature reduction melting and oxidation refining processes. It relates to a harmful gas detoxification treatment apparatus using heat exchange for treating and detoxifying the exhaust gas.

Overseas recycling advanced countries place importance on securing LED waste resource pretreatment technology and conduct research and development, whereas Korea is approaching only from the metal recovery aspect, and the final metal recovery is facilitated by securing technology for LED waste resource pretreatment. There is a demand for the development of pretreatment-metal recovery linkage technology.

Although the technology for recovering Ga and In from LED process waste has been developed through an existing government project supported by the Ministry of Industry, it is not easy to secure economic feasibility because the amount of Ga and In contained in LED is very small.

Therefore, there is a need to develop a technology for recovering a precious metal that is easy to secure economical efficiency from LED waste resources.

On the other hand, the red and IR LED currently used contains arsenic, a class 1 carcinogen, so an integrated plant that recycles LED waste resources regardless of the material used can be built only when a technology to efficiently recover and harmless it is developed. .

However, it is understood that there have been few attempts to recover/harmize arsenic from LED waste resources so far.

Domestic LED waste resource recycling-related pre-treatment, metal recovery, and detoxification treatment technology levels are low compared to advanced countries, so multi-faceted efforts are needed to close the gap.

In the case of overseas, various projects have been carried out to develop efficient recycling technology for several years in preparation for the recycling of LED waste resources that will occur in a large amount in the future.

In Germany, the Fraunhofer Institute for Reliability and Microintegration IZM formed a consortium to carry out the ‘CycLED project’ and develop a technology to economically recover major metals from LED waste resources.

In Norway, an industry, academia, and research consortium is centered on a consortium of industry, academia, and research as a countermeasure against the increasing LED sales volume and the resulting waste treatment. Therefore, it is treated together with existing waste resources.

Meanwhile, in the EU, there is still no clear collection system for LED waste resources, so it is difficult to establish a recycling commercial process.

In general, GaN of blue wavelength is most widely used for the active layer of LED, but photoactive material containing arsenic is used for red and IR LEDs that require a long wavelength.

In particular, as the market for red LED masks for beauty has recently grown, many LEDs containing arsenic are appearing in the market.

Arsenic contained in long-wavelength LEDs is toxic enough to be treated as a class 1 carcinogen, so it is necessary to control the amount of elution and air emissions emitted during the recycling process.

Currently, it is incinerated or landfilled together with general waste, but in a situation where a large amount of waste is expected in the future, it is essential to develop a process that detoxifies arsenic (contains in steam and slag) in order to establish an integrated recycling line for LED waste resources.

Regarding arsenic treatment technology, which is a toxic substance, in Japan, after acid-dissolving GaAs semiconductor, gallium and arsenic are separated using a cerium-based arsenic selective adsorbent, and arsenic is arsenobtaine.

(AsB) is being converted into harmless research.

In China, after pulverizing GaAs scrap, sulfur is added and heat treatment is performed in a nitrogen atmosphere tubular furnace at about 180°C for 40 minutes to form a mixture of arsenic sulfide/gallium, which is then heat treated at 800°C to remove arsenic sulfide.

In addition, a study was conducted to recover arsenic by thermal decomposition at high temperature (1000 ℃)/high pressure (20 Pa) using pyrolysisvacuum metallurgy separation method.

However, this method is still in the research stage, and it is understood that there is no commercialized technology so far.

In order to secure economic feasibility while resolving environmental issues in a situation where investment in recycling LED waste resources, which is expected to be generated in a large amount, or commercial technology development performance is insufficient, expensive precious metals such as Au and Ag and high content of Cu must be recovered. A technology capable of detoxifying harmful substances such as arsenic should also be developed at the same time.

Arsenic contained in long-wavelength red and IR LED waste resources of hazardous substances is typical, and such arsenic may be generated in the form of vapor and slag during the recycling process.

Therefore, in order to construct an integrated recycling plant of LED waste resources, it is necessary to efficiently detoxify arsenic and control the domestic elution (≤ 1.5 mg/L) and air emission standards (≤ 2.0 ppm) below.

The adsorption method is the most representative technique for recovering/detoxifying arsenic, but it seems that a dry/wet fusion process design such as condensation, adsorption, dissolution, and precipitation is required for reliable treatment.

J. of Korean Inst. of Resources Recycling Vol. 28, No. 2, 2019, 14-22.

The present invention has been devised to solve the various problems of the prior art as described above, and contains arsenic, a harmful component, generated in the process of treating waste LEDs through SAF (Submerged Arc Furnace) high-temperature reduction melting and oxidation refining processes. An object of the present invention is to provide an apparatus for detoxifying harmful gas using heat exchange for treating and detoxifying the exhaust gas.

In order to achieve the above objects, the present invention is an exhaust gas injection pipe into which the exhaust gas containing harmful substances is injected; a heat exchange pipe connected to the flue gas inlet pipe in communication with the flue gas introduced from the flue gas inlet pipe to perform heat exchange and harmless at the same time; an exhaust gas discharge pipe connected in communication with the heat exchange pipe to discharge the detoxified exhaust gas from the heat exchange pipe; a hollow casing in which the heat exchange pipe is disposed therein and a cooling water flow path is formed so that the cooling water flows; a cooling water injection pipe disposed on one side of the casing to communicate with the cooling water flow path formed inside the casing and injecting cooling water into the cooling water flow path; and a cooling water discharge pipe disposed on the other side of the casing in communication with the cooling water flow passage formed inside the casing to discharge the cooling water that has cooled the heat exchange pipe to the outside of the casing. A gas detoxification treatment apparatus is provided.

In this case, it is preferable that the heat exchange pipe is formed in plurality.

The heat exchange pipe may include a plurality of branch pipes branching from the exhaust gas inlet pipe, and a plurality of laminating pipes connecting the plurality of branch pipes to the exhaust gas discharge pipe by laminating the plurality of branch pipes.

Specifically, the heat exchange pipe may include: a first branch pipe and a second branch pipe each branched into two from the exhaust gas injection pipe; a first branch pipe and a first-2 branch pipe each branched into two from one end of the first branch pipe connected to the exhaust gas injection pipe and the other end located opposite to the other end; a 2-1 branch pipe and a 2-2 branch pipe each branched into two from one end of the second branch pipe connected to the exhaust gas injection pipe and the other end located on the opposite side; A first joint pipe having one end connected to the other ends respectively located opposite to the ends of the first branch pipe and the first branch pipe 1-2 connected to the other end of the first branch pipe and the other end connected to the exhaust gas discharge pipe ; and

A second joint pipe having one end connected to the other ends respectively positioned opposite to the ends of the second branch pipe and the second branch pipe connected to the other end of the second branch pipe and the other end being connected to the exhaust gas discharge pipe ; may be included.

Such a first branch pipe, a second branch pipe, a first joint pipe and a second joint pipe are horizontally arranged in parallel with the exhaust gas injection pipe and the exhaust gas discharge pipe, and the first branch pipe, the first 1-2 minutes The trachea, the 2-1 branch pipe, and the 2-2 branch pipe are formed by bending a plurality and may be disposed vertically.

Meanwhile, in the heat exchange pipe, a straight fin or a cross fin may be formed along the longitudinal direction in order to improve heat exchange efficiency.

Specific details of other embodiments are included in "Details for carrying out the invention" and the accompanying "drawings".

Advantages and/or features of the present invention, and methods of achieving them, will become apparent with reference to the various embodiments described below in detail in conjunction with the accompanying drawings.

However, the present invention is not limited to the configuration of each embodiment disclosed below, but may be implemented in a variety of different forms, and each embodiment disclosed in this specification makes the disclosure of the present invention complete, It is provided to fully inform those of ordinary skill in the art to which the invention pertains to the scope of the present invention, and it should be understood that the present invention is only defined by the scope of each claim.

According to the means for solving the above problems, the present invention has the following effects.

The present invention is such that the heat exchange pipe includes a plurality of branch pipes branching from the exhaust gas injection pipe and a plurality of lamination pipes connecting the plurality of branch pipes to the exhaust gas discharge pipe, and is simply configured to cool the heat exchange pipe with cooling water. , SAF (Submerged Arc Furnace) It has the effect of easily treating and detoxifying the exhaust gas containing arsenic, which is a harmful component generated in the process of treating waste LEDs through high-temperature reduction melting and oxidation refining processes.

In addition, the present invention has an effect of improving heat exchange efficiency by forming a straight fin or a cross fin in the longitudinal direction of the heat exchange pipe.

1 is a diagram schematically illustrating a process of processing waste LED resources.
2 is a view showing an apparatus for detoxifying harmful gas using heat exchange according to the present invention.
3 is a view showing a state in which a part of the cooling block in FIG. 2 is removed.
4 is a view showing a state in which the entire cooling block in FIG. 2 is removed.
FIG. 5 is a view schematically showing the internal configuration of the apparatus for detoxifying harmful gas using heat exchange of FIG. 2 as viewed from the direction A. FIG.
6 is a view schematically showing the internal configuration of the apparatus for detoxifying harmful gas using the heat exchange of FIG. 2 as viewed from above.
7 is a view showing a state in which a straight fin is formed in the tube employed in the apparatus for detoxifying harmful gas using heat exchange according to the present invention.
FIG. 8 is a view illustrating a state in which FIG. 7 is viewed from above in another direction.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Before describing the present invention in detail, the terms or words used in this specification should not be construed as being unconditionally limited to their ordinary or dictionary meanings, and in order for the inventor of the present invention to describe his invention in the best way It should be understood that the concepts of various terms can be appropriately defined and used, and further, these terms or words should be interpreted as meanings and concepts consistent with the technical idea of the present invention.

That is, the terms used herein are only used to describe preferred embodiments of the present invention, and are not used for the purpose of specifically limiting the content of the present invention, and these terms represent various possibilities of the present invention. It should be understood that the term has been defined with consideration in mind.

Also, in the present specification, it should be noted that, unless the context clearly indicates otherwise, the expression in the singular may include a plurality of expressions, and may include the meaning of the singular even if similarly expressed in plural. do.

In the case where it is stated throughout this specification that a component "includes" another component, it does not exclude any other component, but further includes any other component unless otherwise stated. It could mean that you can.

Furthermore, when it is described that a certain component is "exists in or is connected to" of another component, this component may be directly connected or installed in contact with another component, and a certain It may be installed spaced apart at a distance, and in the case of being installed spaced apart by a certain distance, a third component or means for fixing or connecting the component to another component may exist, and now It should be noted that the description of the components or means of 3 may be omitted.

On the other hand, when it is described that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the third element or means does not exist.

Similarly, other expressions describing the relationship between components, such as "between" and "immediately between", or "neighboring to" and "directly adjacent to", have the same meaning. should be interpreted as

In addition, in this specification, terms such as "one side", "the other side", "one side", "the other side", "first", "second", etc., if used, with respect to one component, this single component It is used to be clearly distinguished from other components, and it should be understood that the meaning of the component is not limitedly used by such terms.

In addition, in the present specification, terms related to positions such as "upper", "lower", "left", and "right", if used, should be understood as indicating a relative position in the drawing with respect to the corresponding component, Unless an absolute position is specified with respect to their position, these position-related terms should not be construed as referring to an absolute position.

Furthermore, in the specification of the present invention, terms such as “…unit”, “…group”, “module”, “device”, etc., if used, mean a unit capable of processing one or more functions or operations, which means hardware Alternatively, it should be understood that it may be implemented in software, or a combination of hardware and software.

In addition, in this specification, in specifying the reference numerals for each component of each drawing, the same component has the same reference number even if the component is shown in different drawings, that is, the same reference is made throughout the specification. Symbols indicate identical components.

In the drawings attached to this specification, the size, position, coupling relationship, etc. of each component constituting the present invention are partially exaggerated, reduced, or omitted for convenience of explanation or in order to sufficiently clearly convey the spirit of the present invention. may be described, and therefore the proportion or scale may not be exact.

In addition, in the following, in describing the present invention, a detailed description of a configuration determined that may unnecessarily obscure the gist of the present invention, for example, a detailed description of a known technology including the prior art may be omitted.

1 is a diagram schematically illustrating a process of processing waste LED resources.

The domestic LED market is worth about 7 trillion won as of 2017 and is growing at an average annual rate of 18.7%.

As the usage of LEDs increases rapidly, the amount of process waste resources generated during product production is also increasing, and it is expected that the amount of LED waste lights that are damaged or expired will increase significantly in the future.

Although these LED waste resources contain valuable metals such as gold (Au), silver (Ag), copper (Cu), gallium (Ga), and indium (In), investment in recycling or technology development is very insufficient. am.

In addition, in the case of arsenic, which is a class 1 carcinogen used in long-wavelength LEDs, is not made harmless and is simply buried, so the technical/institutional infrastructure for verification of harmfulness or systematic management is insufficient.

1 is a diagram schematically illustrating a process of processing waste LED resources.

In general, in the process of treating waste LED resources, as shown in FIG. 1, waste LED raw materials are reduced and melted at a high temperature, and arsenic-containing harmful gases generated during this high-temperature reduction and melting process are detoxified in a heat exchange device, and in a heat exchange device. Among the detoxified exhaust gases, fume and fine dust are collected and removed by a bag filter, and the exhaust gas generated during the above-described process is neutralized to below the specified concentration using a scrubber to stand by. through the process of discharging

Here, the waste LED raw material means process waste resources generated during LED manufacturing and LED after use.

In addition, high-temperature reduction melting refers to a submerged arc furnace (SAF) process applied to concentrate a target metal from a waste resource.

In addition, the bag filter is a type of filter and dust collection device, and refers to a filter that filters the dust stream by using a fine sack-shaped filter medium such as glass fiber, cotton, wool, synthetic fiber, or asbestos.

Since the dust attached to the inner surface of the bag filter gradually accumulates and increases the pressure loss, it is dropped when a constant load is applied.

For dropping, methods such as counter air flow, vibration, and shunt are used, and the operation is generally performed to suppress pressure loss to 150 mmAq or less.

The dropping method is divided into intermittent type and continuous type.

The former is a method in which one of several divided rooms is blocked and dropped in order, and the latter is a method in which the processing gas is not blocked and some of the manure cloth is dropped sequentially in sequence.

The bag filter used to treat the high-temperature exhaust gas is preferably made of synthetic fiber or glass fiber.

On the other hand, a scrubber refers to a device that collects suspended solid and liquid fine particles in a gas using a liquid, and is also called a dust collector.

Such a scrubber has various types, such as a spray top, a cyclone scrubber, a ventry scrubber, and a Tizen washer.

As the liquid used in the scrubber, water is generally used.

As a dust collector can expect relatively high collection efficiency, it is an effective method if there is no problem in wastewater treatment (radioactive off-gas treatment method).

Also, an absorber that absorbs and removes insoluble gas components with a liquid is also called a scrubber.

2 to 6 are views showing an apparatus for detoxifying harmful gas using heat exchange according to the present invention.

The apparatus for detoxifying harmful gas using heat exchange according to the present invention includes an exhaust gas injection pipe 10 , a heat exchange pipe 20 , an exhaust gas discharge pipe 30 , a casing 40 , a cooling water injection pipe 50 , and a cooling water discharge pipe 60 . ) is included.

The exhaust gas injection pipe 10 is an exhaust gas containing harmful substances such as arsenic generated through a submerged arc furnace (SAF) process applied to concentrate the target metal from the process waste resources generated during LED manufacturing and the LED after use, which will be described later. It is for injection into the heat exchange pipe (20).

One end of the exhaust gas injection pipe 10 passes through the casing 40 to be described later and is connected to the heat exchange pipe 20 disposed inside the casing 40 .

The heat exchange pipe 20 is connected to the exhaust gas injection pipe 10 in communication with the exhaust gas flowing in from the exhaust gas injection pipe 10 and heat exchange is performed and harmless at the same time. Thermoelectric devices such as aluminum, titanium, stainless steel, etc. It is made of a metal material with excellent conductivity.

It is preferable that such a heat exchange pipe 20 is formed in plurality.

That is, the heat exchange pipe 20 may include a plurality of branch pipes branching from the exhaust gas injection pipe 10 , and a plurality of lamination pipes connecting the plurality of branch pipes to the exhaust gas discharge pipe 30 to be described later.

Specifically, the heat exchange pipe 20 includes a first branch pipe 21 and a second branch pipe 22 each branched into two from the exhaust gas injection pipe 10 , and a first branch pipe connected to the exhaust gas injection pipe 10 . The second branch pipe (22) connected to the first branch pipe (23) and the second branch pipe (24) and the exhaust gas injection pipe (10) respectively branched into two from the other end located opposite to the one end of (21). ), the 2-1 branch pipe 25 and the 2-2 branch pipe 26 branched into two from the other end located opposite to the one end, respectively, and the 1-1 branch connected to the other end of the first branch pipe 21 One end is connected to the other ends respectively located opposite to the ends of the engine 23 and the first and second branch pipes 24 and the other end is a first joint pipe 27 connected to the exhaust gas discharge pipe 30, and a second One end is connected to the other ends respectively located opposite to the ends of the second branch pipe 25 and the second branch pipe 26 connected to the other end of the branch pipe 22, and the other end is the exhaust gas discharge pipe 30 It may include a second joint pipe 28 connected to.

The first branch pipe 21 , the second branch pipe 22 , the first joint pipe 27 and the second joint pipe 28 are horizontally parallel to the exhaust gas injection pipe 10 and the exhaust gas discharge pipe 30 . and the 1-1 branch pipe 23, the 1-2 branch pipe 24, the 2-1 branch pipe 25 and the 2-2 branch pipe 26 are formed by bending a plurality of vertical can be placed.

At this time, the first branch pipe 21, the second branch pipe 22, the first joint pipe 27, the second joint pipe 28, the 1-1 branch pipe 23, the 1-2 branch pipe (24), the 2-1 branch pipe 25, and the 2-2 branch pipe 26 are disposed inside the casing 40, which will be described later, so that heat exchange is performed by cooling water.

The exhaust gas discharge pipe 30 is connected in communication with the first joint pipe 27 and the second joint pipe 28, respectively, and the heat exchange pipe 20, that is, the first branch pipe 21, the second branch pipe 22, The first joint pipe 27, the second joint pipe 28, the 1-1 branch pipe 23, the 1-2 branch pipe 24, the 2-1 branch pipe 25 and the 2-2 branch pipe The detoxified exhaust gas is discharged from the branch pipe 26 .

The casing 40 is hollow, the heat exchange pipe 20 is disposed therein, and the cooling water flow passage 42 is formed so that the cooling water flows.

The coolant injection pipe 50 is disposed on one side of the casing 40 in communication with the coolant flow passage 42 formed inside the casing 40 to inject coolant into the coolant flow passage 42 from the outside.

The cooling water discharge pipe 60 is disposed on the other side of the casing 40 (preferably, the side opposite to the side on which the cooling water injection pipe 50 is disposed) so as to communicate with the cooling water flow path 42 formed inside the casing 40. The cooling water cooled by the heat exchange pipe 20 while flowing along the cooling water flow passage 42 is discharged to the outside of the casing 40 .

7 is a view showing a state in which a straight fin is formed in a tube employed in the apparatus for detoxifying harmful gas using heat exchange according to the present invention, and FIG.

Fins F may be formed in the heat exchange pipe 20 along the longitudinal direction to improve heat exchange efficiency, and these fins may be straight fins or cross fins.

Tables 1 and 2 below compare the heat exchange efficiency when the fin (F) is formed in the heat exchange pipe 20 and when it is not formed.

[Table 1]

[Table 2]

As can be seen from Tables 1 and 2, the shape of the heat exchange pipe 20 is a first branch pipe 21 , a second branch pipe 22 , a first joint pipe 27 , and a second joint pipe 28 . , the 1-1 branch pipe 23 , the 1-2 branch pipe 24 , the 2-1 branch pipe 25 and the 2-2 branch pipe 26 , and the heat exchange pipe 20 In the case of mode Ⅲ, in which straight or cross-shaped fins were formed inside, the thermal efficiency was found to be the best.

In the above, although several preferred embodiments of the present invention have been described with some examples, the description of various various embodiments described in the "Specific Contents for Carrying Out the Invention" item is merely exemplary, and the present invention Those of ordinary skill in the art will understand well that the present invention can be practiced with various modifications or equivalents to the present invention from the above description.

In addition, since the present invention can be implemented in various other forms, the present invention is not limited by the above description, and the above description is for the purpose of completing the disclosure of the present invention, and it is common in the technical field to which the present invention belongs. It should be understood that the present invention is only provided to fully inform those with knowledge of the scope of the present invention, and that the present invention is only defined by each of the claims.

10: exhaust gas injection pipe
20: heat exchange pipe
21: 1st branch organ
22: 2nd branch
23: Branch 1-1
24: branch 1-2
25: Branch 2-1
26: branch 2-2
27: 1st joint building
28: 2nd joint building
F : Straight pin (FIN)
30: exhaust gas discharge pipe
40: casing
42: coolant flow path
50: coolant injection pipe
60: cooling water discharge pipe

Claims (6)

an exhaust gas injection pipe into which an exhaust gas containing harmful substances is injected;
a plurality of heat exchange pipes connected to the flue gas inlet pipe in communication with the flue gas introduced from the flue gas inlet pipe to perform heat exchange and harmless at the same time;
an exhaust gas discharge pipe connected in communication with the heat exchange pipe to discharge the detoxified exhaust gas from the heat exchange pipe;
a hollow casing in which the heat exchange pipe is disposed and a cooling water flow passage is formed so that the cooling water flows;
a cooling water injection pipe disposed on one side of the casing to communicate with the cooling water flow passage formed inside the casing and injecting cooling water into the cooling water flow passage; and
a cooling water discharge pipe disposed on the other side of the casing in communication with the cooling water flow passage formed inside the casing to discharge the cooling water that has cooled the heat exchange pipe to the outside of the casing; and
The heat exchange pipe includes a plurality of branch pipes branching from the exhaust gas inlet pipe, and a plurality of lamination pipes connecting the plurality of branch pipes to the exhaust gas discharge pipe by laminating them,
Characterized in that a straight fin or a cross fin is formed in the longitudinal direction of the heat exchange pipe to improve heat exchange efficiency,
A device for detoxifying harmful gases using heat exchange.
delete delete The method according to claim 1,
The heat exchange pipe is
a first branch pipe and a second branch pipe each branched into two from the exhaust gas injection pipe;
a branch pipe 1-1 and a branch pipe 1-2 respectively branched in two from one end of the first branch pipe connected to the exhaust gas injection pipe and the other end located opposite to the other end;
a 2-1 branch pipe and a 2-2 branch pipe each branched into two from one end of the second branch pipe connected to the exhaust gas injection pipe and the other end located on the opposite side;
A first joint pipe having one end connected to the other ends respectively located opposite to the ends of the first branch pipe and the first branch pipe 1-2 connected to the other end of the first branch pipe and the other end connected to the exhaust gas discharge pipe ; and
A second joint pipe having one end connected to the other ends respectively located opposite to the ends of the 2-1 branch pipe and the 2-2 branch pipe connected to the other end of the second branch pipe and the other end connected to the exhaust gas discharge pipe characterized in that it contains;
A device for detoxifying harmful gases using heat exchange.
5. The method according to claim 4,
The first branch pipe, the second branch pipe, the first joint pipe and the second joint pipe are horizontally arranged in parallel with the exhaust gas injection pipe and the exhaust gas discharge pipe,
The 1-1 branch pipe, the 1-2 branch pipe, the 2-1 branch pipe and the 2-2 branch pipe are formed by bending a plurality and are vertically arranged,
A device for detoxifying harmful gases using heat exchange.
delete

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