Device and method for reducing dioxin emissions from organic coating pyrolysis flue gas

Abstract

The present invention discloses a device and method for reducing dioxin emissions in flue gas from the pyrolysis of an organic coating, and belongs to the technical field of dioxin emission reduction. The device comprises an organic coating pyrolysis unit, an adsorption unit, an inhibitor spraying unit, and a tar separation unit. The organic coating pyrolysis unit is connected to the tar separation unit via a flue gas outlet pipe, and the flue gas outlet pipe and the organic coating pyrolysis unit are respectively connected to the inhibitor spraying unit. The flue gas outlet of the tar separation unit is connected to the adsorption unit via a pipeline. By optimizing the overall structure of the emission reduction device, the present invention can effectively treat dioxins generated during the pyrolysis of the organic coating, with a significant emission reduction effect. At the same time, by scientifically and rationally controlling the spraying amount of the inhibitor during treatment, not only is dioxin emission reduction achieved, so that the emission concentration of dioxins meets national standards, but also the spraying amount of dioxin inhibitors during the pyrolysis process is reduced, saving costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of dioxin emission reduction, and in particular relates to a device and method for reducing dioxin emission in organic coating pyrolysis flue gas. Background Art

[0002] With the gradual depletion of non-ferrous metal mineral resources, the recycling of secondary resources has become an effective supplement. Scrap electronic-grade copper, a typical secondary non-ferrous metal resource, is primarily recycled through pyrolysis. However, due to the organic coating on its surface, the pyrolysis process produces dioxins, the most toxic pollutants known to mankind. Dioxins are considered one of the world's most dangerous chemicals and the poison of the century. Once released into the atmosphere, dioxins are difficult to eliminate. Dioxins are 130 times more toxic than the highly toxic substances cyanide and 900 times more toxic than arsenic. Experiments have shown that even low concentrations of dioxins can be lethal to animals. Inhalation of dioxins can cause skin diseases, headaches, deafness, depression, insomnia, and may also lead to chromosomal damage, heart failure, and cancer. Dioxins can also cause fetal growth problems. Dioxins can enter the human body through food, air, and skin contact. Once inside, they are difficult to break down. They are carcinogenic, teratogenic, and mutagenic, and they also have endocrine disrupting properties. Therefore, how to reduce the emission of dioxins in the pyrolysis flue gas of organic coatings has become a difficult problem that needs to be solved urgently.

[0003] Traditional methods for reducing dioxin emissions from pyrolysis flue gas from organic coatings include spraying inhibitors and adsorption with adsorbents. The main inhibitory mechanisms of dioxin inhibitors can be summarized as reducing dioxin production by consuming chlorine sources (Cl2, HCl) or changing the form of the chlorine source. For example, SO2 can convert Cl2 into less active HCl; reacting with metal catalysts, passivating the catalytic effect, thereby reducing the metal catalyst's catalytic efficiency for dioxin formation; and reacting with dioxin precursors, hindering the precursor's reaction to form dioxins. At the tail end of the flue gas, adsorbents (such as activated carbon) are often used to retain dioxins in the adsorbent. Both methods can reduce the dioxin content in pyrolysis flue gas, but they also face two problems: controlling the amount of inhibitor sprayed and the limited adsorption effect of adsorbents alone.

[0004] Dioxin inhibitors are commonly sprayed into pyrolysis flue gases through nozzles, but the amount of inhibitor sprayed is difficult to control. For non-continuous organic coating pyrolysis furnaces, the operation process includes loading, heating, insulation, and cooling. Dioxins are not constantly generated during the pyrolysis of organic coatings, and the generation rate is not constant. If the inhibitor is continuously sprayed in a fixed amount, during periods of no dioxin generation or low generation rate, the inhibitor will be overdosed, wasting the inhibitor and increasing the cost of dioxin emission reduction. During periods of high dioxin generation, the amount may be insufficient, resulting in limited inhibitory capacity and ineffective results. Therefore, the amount of inhibitor sprayed is particularly critical.

[0005] After searching, the name of the Chinese patent is: "A dioxin emission reduction system in an incineration process with adding inhibitors in multiple temperature stages" (201720900885.X). This method adds inhibitors at different temperatures, but the patent document only considers the effect of temperature on dioxin formation, and does not add according to the dioxin formation rate, which is slightly limited.

[0006] After many experiments, the applicant found that during the pyrolysis process of the organic coating, dioxins are mainly formed on the surface of the tar. Therefore, reducing the emission of dioxins in the pyrolysis flue gas of the organic coating can be achieved by treating the tar in the flue gas. After searching, the name of the Chinese patent is: "A low-tar domestic waste pyrolysis system and method for inhibiting dioxin generation" (CN202010068402). This method provides a triple continuous material seal to create an anaerobic environment for anaerobic pyrolysis, avoid the conditions for the formation of dioxins, reduce tar production, and thus achieve the reduction of the content of dioxins produced during the pyrolysis process of domestic waste and complete emission reduction. However, this method is generally effective in reducing tar, the conditions for dioxin generation are difficult to control, and the emission reduction effect is limited.

[0007] For example, the Chinese patent titled "A Waste Incinerator with a Square Rotating Air Separator for Dioxin Elimination" (CN202110049786.6) passes flue gas through a square rotating air separator, increasing its residence time, separating solid particles, and eliminating dioxins. However, its effectiveness in separating tar is limited, as the surface of tar is a prime location for dioxin formation, making dioxin reduction less than ideal. Summary of the Invention

[0008] 1. Problem to be solved

[0009] In response to the problems raised in the above background technology, the present invention provides a dioxin emission reduction device in the flue gas from the pyrolysis of organic coatings. Through the setting of an organic coating pyrolysis unit, an inhibitor spraying unit, a tar separation unit and an adsorption unit, the dioxins generated during the pyrolysis process of the organic coating can be effectively treated, and the emission reduction effect is significant.

[0010] At the same time, the present invention also provides a method for reducing dioxin emissions in organic coating pyrolysis flue gas. By using the emission reduction device of the present invention and scientifically and rationally controlling the spraying amount of the inhibitor, the dioxin in the organic coating pyrolysis flue gas is effectively treated. The treatment method is simple, low-cost, and has high economic benefits.

[0011] 2. Technical solution

[0012] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0013] The present invention provides a device for reducing dioxin emissions from organic coating pyrolysis flue gas, comprising an organic coating pyrolysis unit, an adsorption unit, an inhibitor spraying unit, and a tar separation unit. The organic coating pyrolysis unit is connected to the tar separation unit via a flue gas outlet pipe, and the flue gas outlet pipe and the organic coating pyrolysis unit are respectively connected to the inhibitor spraying unit. The flue gas outlet of the tar separation unit is connected to the adsorption unit via a pipe. The present invention adds an inhibitor spraying unit, and in particular, connects the inhibitor spraying unit to the organic coating pyrolysis unit and the flue gas outlet pipe respectively. During the pyrolysis process of the organic coating, an inhibitor is sprayed onto the generated pyrolysis flue gas. At the same time, the inhibitor is sprayed again when the pyrolysis flue gas enters the flue gas outlet pipe. The pyrolysis flue gas enters the tar separation unit along with the inhibitor and is fully mixed in the tar separation unit, thereby further improving the inhibitory effect.

[0014] As a further preferred embodiment of the present invention, the inhibitor spraying unit includes a first nozzle, a second nozzle and an inhibitor storage tank. The first nozzle is arranged directly above the pyrolysis furnace body of the organic coating pyrolysis unit, and the first nozzle is connected to the inhibitor storage tank through a pipe. The second nozzle is arranged in the flue gas outlet pipe and is connected to the inhibitor storage tank. The nozzle is made of high-temperature resistant material, and the first nozzle is arranged at the center of the top of the pyrolysis furnace. In addition, more optimally, a first jet pump and a first flow valve are provided on the pipe connecting the first nozzle and the inhibitor storage tank; a second jet pump and a second flow valve are provided on the pipe connecting the second nozzle and the inhibitor storage tank. The setting of the flow valve and the jet pump facilitates real-time adjustment of the amount of inhibitor sprayed.

[0015] As a further preferred embodiment of the present invention, it further includes an activated carbon powder nozzle, which is arranged on the top of the pyrolysis furnace body of the organic coating pyrolysis unit.

[0016] As a further preference of the present invention, the tar separation unit includes a cyclone separator body, which is provided with a cyclone separator feed port and a cyclone separator discharge port. The cyclone separator feed port is connected to the flue gas outlet pipe, and the cyclone separator discharge port is connected to the adsorption unit through a pipe. During actual installation, one end of the flue gas outlet pipe is controlled to be tangent to the cyclone separator cone, so that the flue gas enters the cyclone separator tangentially, and the flue gas airflow changes from linear motion to circular motion.

[0017] As a further preferred embodiment of the present invention, a filter cloth is fixedly mounted on the circumferential inner sidewall of the cyclone separator body. The filter cloth is made of a high-temperature-resistant material capable of withstanding temperatures exceeding 300 degrees Celsius and is laid on the conical sidewall of the cyclone separator. Furthermore, a layer of activated carbon powder is adsorbed onto the surface of the filter cloth via an electrostatic generator. The static electricity generated by the electrostatic generator is applied to the filter cloth, creating electrostatic attraction between the filter cloth and the activated carbon powder, facilitating adhesion of the activated carbon powder.

[0018] The principle of tar separation using the tar separation unit of the present invention is as follows: the flue gas generated by pyrolysis enters the cyclone separator tangentially, the flue gas flow changes from linear motion to circular motion, and the rotating airflow flows downward in a spiral along the wall of the device. Under the action of centrifugal force, the tar in the flue gas is thrown toward the filter cloth on the wall of the device. The filter cloth has activated carbon powder adsorbed by electrostatics, and the viscosity of the tar causes it to adhere to the activated carbon powder. The flue gas flow rotating downward continuously flows into the center of the cyclone separator during the descent process, forming a centripetal radial airflow, forming an upward rotating inner vortex. The inner and outer vortexes rotate in the same direction. The flue gas flow that does not contain tar flows upward from the middle pipe of the cyclone separator and enters the adsorption unit for adsorption, thereby effectively reducing the dioxin content in the flue gas from the pyrolysis of the organic coating.

[0019] As a further preference of the present invention, it also includes a third nozzle and an activated carbon powder collection hopper, wherein the third nozzle is fixedly mounted on the circumferential outer wall of the cyclone separator body; the activated carbon powder collection hopper is detachably mounted on the bottom of the cyclone separator body. By setting the third nozzle, the filter cloth without static electricity can be sprayed, and the activated carbon powder that has lost its electrostatic adsorption can be blown into the activated carbon powder collection hopper for recovery. The recovered activated carbon powder with tar adhered thereto can be sprayed into a pyrolysis furnace for recycling.

[0020] As a further preferred embodiment of the present invention, the third nozzles include a plurality of nozzles, evenly spaced and arranged on the sidewalls of the cyclone separator body, for spraying activated carbon powder onto the filter cloth. By optimizing the installation position and number of the third nozzles, the spraying effect is improved, facilitating the cleaning of tar within the cyclone separator, making cleaning simple, convenient, and cost-effective.

[0021] As a further preferred embodiment of the present invention, the adsorption unit utilizes activated carbon to absorb and separate dioxins from the flue gas after tar removal. The activated carbon saturated with dioxins in the adsorption unit can be pulverized in a low-temperature, high-pressure nitrogen environment and then used in the cyclone separator of the tar separation unit, allowing the separated tar to adhere to the activated carbon powder, thereby enabling waste recycling.

[0022] As a further preferred embodiment of the present invention, the dioxins generated during the pyrolysis of the organic coating are treated using the above-mentioned emission reduction device, comprising the following steps:

[0023] (1) The waste material containing the organic coating is pyrolyzed in the pyrolysis furnace body, and activated carbon powder and inhibitor are sprayed into the pyrolysis furnace during the pyrolysis process;

[0024] (2) When the pyrolysis flue gas enters the flue gas outlet pipe, the inhibitor begins to be sprayed. The pyrolysis flue gas carrying the inhibitor enters the cyclone separator body of the tar separation unit for treatment. The tar in the form of fine droplets in the flue gas can be separated by the cyclone separator and retained in the tar separation unit. The flue gas without tar flows out of the tar separation unit and finally enters the adsorption unit for adsorption treatment. The emission reduction is completed after the activated carbon adsorbs the dioxins in the flue gas.

[0025] (3) The third nozzle is turned on to spray the filter cloth on the side wall of the cyclone separator body. The activated carbon powder collection bucket collects the activated carbon powder adhering to tar that is blown down. The recovered activated carbon powder can be sprayed into the pyrolysis furnace again for recycling.

[0026] As a further preferred embodiment of the present invention, during the pyrolysis process, the flow rate Q of the sprayed inhibitor satisfies the following relationship:

[0027] Q=247t 2 -348.8t+171.03

[0028] Wherein, the unit of Q is L / h, and t is the pyrolysis time in h.

[0029] 3. Beneficial effects

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The device for reducing dioxins in organic coating pyrolysis flue gas of the present invention can effectively adhere the separated tar to the activated carbon powder on the filter cloth on the wall of the device by optimizing the overall structure of the device. After the pyrolysis is completed, the activated carbon powder adheres to the tar to saturation. By blowing air on the filter cloth after the static electricity is removed, the activated carbon powder that has lost its static adsorption falls off and falls into the collection bucket. The activated carbon powder is sprayed into the pyrolysis furnace by the activated carbon powder nozzle and burned. The dioxins in the tar can be directly cracked and destroyed, and the combustion of tar and activated carbon powder provides heat for the pyrolysis process. The operation is simple and the economic benefit is high.

[0032] (2) In the device for reducing dioxins in organic coating pyrolysis flue gas of the present invention, after the activated carbon in the adsorption unit has been saturated with dioxins, it can be crushed in a low-temperature, high-pressure nitrogen environment and used in a tar separation unit to adhere to the separated tar for reuse. At the same time, the activated carbon powder adhered to the tar collected in the tar separation unit can be sprayed into a pyrolysis furnace for recycling. The activated carbon powder adhered to the tar contains saturated dioxins and can be sprayed into the pyrolysis furnace together with the dioxins in the tar for cracking and destruction, thereby completing the harmless and zero-emission treatment of dioxins.

[0033] (3) The present invention relates to a method for reducing dioxin emissions from pyrolysis flue gas of an organic coating. Inhibitors can be sprayed into the flue gas at varying flow rates depending on the dioxin generation situation. The inhibitors then enter the tar separation unit together with the flue gas, where they are fully mixed in the cyclone separator, resulting in a better inhibitory effect. Furthermore, based on extensive research, a precise formula for the spraying rate of the inhibitors has been developed. By using this formula to determine the spraying rate of the inhibitors, the dioxin generation rate is rationally controlled, and the inhibitory effect is significantly improved, thereby significantly reducing the cost of dioxin reduction and simplifying the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic structural diagram of a device for reducing dioxin emissions from organic coating pyrolysis flue gas according to the present invention.

[0035] Figure 2 Schematic diagram of the structure of the tar separation unit in the present invention; Figure 2 The arrows in the figure are the directions of flue gas flow, the long downward arrows are the longitudinal directions of the flue gas external vortex flow, the long upward arrows are the longitudinal directions of the flue gas internal vortex flow, and the curved arrows are the directions of the internal and external vortex flows.

[0036] Figure 3 Schematic diagram of the top view of the tar separation unit of the present invention; Figure 3 The middle arrow indicates that the direction of the flue gas flow changes from linear motion to circular motion.

[0037] Figure 4 is the fitting curve graph.

[0038] In the picture:

[0039] 100. Organic coating pyrolysis unit; 110. Pyrolysis furnace body; 120. Activated carbon powder nozzle;

[0040] 200, inhibitor spraying unit; 210, inhibitor storage tank; 221, first flow valve; 222, second flow valve; 231, first jet pump; 232, second jet pump; 241, first nozzle; 242, second nozzle;

[0041] 300, tar separation unit; 310, cyclone separator feed port; 320, filter cloth; 330, activated carbon powder; 340, third nozzle; 350, activated carbon powder collection hopper; 360, cyclone separator discharge port; 370, cyclone separator body;

[0042] 400. Adsorption unit. DETAILED DESCRIPTION

[0043] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0044] It should be noted that when an element is referred to as being "fixed on" another element, it may be directly on the other element or there may also be an element in the middle; when an element is considered to be "connected to" another element, it may be directly connected to the other element or there may also be an element in the middle; the terms "vertical", "horizontal", "left", "right" and similar expressions used in this article are for illustrative purposes only.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains; the terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0046] The present invention will be further described below with reference to specific embodiments.

[0047] Example 1

[0048] like Figure 1-3As shown, a dioxin emission reduction device in organic coating pyrolysis flue gas of this embodiment includes an organic coating pyrolysis unit 100, a tar separation unit 300, an adsorption unit 400 and an inhibitor spraying unit 200. The organic coating pyrolysis unit 100 is connected to the tar separation unit 300 through a flue gas outlet pipe, and the flue gas outlet pipe and the organic coating pyrolysis unit 100 are respectively connected to the inhibitor spraying unit 200; the flue gas outlet of the tar separation unit 300 is connected to the adsorption unit 400 through a pipe.

[0049] Specifically, such as Figure 1 As shown, the organic coating pyrolysis unit 100 of the present invention includes a pyrolysis furnace body 110, which is used to pyrolyze waste materials requiring pyrolysis treatment, such as scrap copper enameled wire. A first nozzle 241 is located directly above the pyrolysis furnace body 110 for spraying an inhibitor into the pyrolysis furnace body 110. The pyrolysis flue gas outlet of the organic coating pyrolysis unit 100 is connected to one end of a flue gas outlet pipe, the other end of which is connected to the cyclone separator body 370 of the tar separation unit 300. The top center of the cyclone separator body 370 is connected to the adsorption unit 400 via a pipe. The cyclone separator body 370 in the tar separation unit 300 separates tar from the flue gas during the pyrolysis process of the organic coating pyrolysis unit 100, removing dioxins adsorbed on the tar surface. The pyrolysis flue gas then passes through the adsorption unit 400, where any remaining gaseous dioxins are adsorbed. Finally, the flue gas is discharged through a pipe.

[0050] As another implementation of this embodiment, an activated carbon powder nozzle 120 is further provided on the top of the pyrolysis furnace body 110. The activated carbon powder nozzle 120 is provided on one side of the top of the pyrolysis furnace body 110 of the organic coating pyrolysis unit 100, at a height of 0.5 m from the top of the pyrolysis furnace body 110. Figure 1 As shown in the center position, the activated carbon nozzle 120 is located 0.5 m to the left of the top of the pyrolysis furnace body 110 and is used to spray activated carbon powder 330 and the like into the pyrolysis furnace body 110. The combustion heat released by the activated carbon powder 330 and the like also provides heat for the pyrolysis process.

[0051] As another embodiment of this embodiment, the inhibitor spraying unit 200 described in this embodiment includes a first nozzle 241, a second nozzle 242, and an inhibitor storage tank 210. Both the first nozzle 241 and the second nozzle 242 are connected to the inhibitor storage tank 210 via pipes, and the inhibitor storage tank 210 supplies the first and second nozzles 241 and 242 with inhibitor solution. The first nozzle 241 is located at the top center of the pyrolysis furnace body 110. By spraying the inhibitor solution onto the organic coating pyrolysis unit 200, dioxin formation within the pyrolysis furnace can be effectively reduced. Simultaneously, the second nozzle 242 is positioned within the flue gas outlet pipe to spray the inhibitor solution. Positioning the second nozzle 242 near the flue gas outlet of the organic coating pyrolysis unit 100 ensures that the inhibitor is sprayed onto the flue gas immediately upon entering the flue gas outlet pipe.

[0052] Furthermore, in this embodiment, the pipeline connecting the inhibitor storage tank 210 and the first nozzle 241 is equipped with a first flow valve 221 and a first jet pump 231. The first flow valve 221 is located near the inhibitor storage tank 210 and is used to adjust the flow rate of the first nozzle 241, while the first jet pump 231 is used to pressurize the inhibitor solution. Simultaneously, the pipeline connecting the inhibitor storage tank 210 and the second nozzle 242 is equipped with a second flow valve 222 and a second jet pump 232. The second flow valve 222 is located near the inhibitor storage tank 210 and is used to adjust the flow rate of the second nozzle 242, while the second jet pump 232 is used to pressurize the inhibitor solution. The inhibitor solution used in the present invention can be an inhibitor solution containing ammonia groups, such as a urea solution or an ammonia solution. It can also be an alkaline solution, such as a calcium hydroxide solution, or a mixture of multiple inhibitor solutions.

[0053] As another implementation of this embodiment, Figure 1-3 As shown, the cyclone separator body 370 in the tar separation unit 300 described in this embodiment has a tapered structure with a diameter that decreases from top to bottom, with a taper of 170° to 175°. It is used to separate tar from pyrolysis flue gas. A cyclone separator feed port 310, also known as the flue gas inlet channel, is provided on one side of the top of the cyclone separator body 370. This allows the pyrolysis flue gas to enter the cyclone separator body 370. The end of the flue gas outlet pipe is tangential to the cyclone separator feed port 310, allowing the flue gas entering the cyclone separator body 370 to rotate along the inner wall of the cone of the cyclone separator body 370, converting the flue gas flow from linear motion to circular motion. The flue gas is finally transported to the adsorption unit 400 through a duct via a cyclone separator outlet 360 located in the middle of the top of the cyclone separator body 370.

[0054] Existing adsorbents can be used to adsorb the dioxins remaining in the flue gas from which the tar has been removed. To further improve the adsorption effect, specifically, the adsorption unit 400 described in this embodiment uses an activated carbon adsorption box with a size of 2.5m*1.0m*1.3m, and an internal configuration of 332 honeycomb activated carbon blocks with a size of 100*100*100mm. The flue gas after the tar is separated passes through the adsorption unit 400, and the adsorption unit 400 adsorbs the gaseous dioxins remaining in the flue gas, and the flue gas after the dioxins are adsorbed flows out through the pipeline.

[0055] As another embodiment of this embodiment, a filter cloth 320 is fixedly mounted on the circumferential inner wall of the cyclone separator body 370. The pore size of the filter cloth 320 is 106 μm to 150 μm. A layer of activated carbon powder 330 is adsorbed on the surface of the filter cloth 320 by an electrostatic generator. The static electricity generated by the electrostatic generator is applied to the filter cloth 320, so that the activated carbon powder 330 can be electrostatically adsorbed on the surface of the filter cloth 320. The specific surface area of ​​the activated carbon powder 330 is 600 m 2 / g~800m 2 / g. Through the above arrangement, when tar is separated from pyrolysis flue gas, the separation principle is as follows: the flue gas generated by pyrolysis is introduced tangentially into the cyclone separator, where the flue gas flow changes from linear motion to circular motion, with the rotating airflow spiraling downward along the wall of the separator. Under the action of centrifugal force, the tar in the flue gas is flung toward the filter cloth 320 on the wall. Activated carbon powder 330 is electrostatically adsorbed on the filter cloth 320, and the viscosity of the tar causes it to adhere to the activated carbon powder 330. As it descends, the spiraling flue gas continuously flows toward the center of the cyclone separator, forming a centripetal radial flow and an upward-spinning inner vortex. The inner and outer vortices rotate in the same direction. The tar-free flue gas flows upward from the central duct of the cyclone separator and enters the adsorption unit for adsorption, effectively reducing the dioxin content in the flue gas from the pyrolysis of the organic coating.

[0056] The existing method of using a cyclone separator for tar separation generally has the disadvantages of being difficult to clean, time-consuming and labor-intensive, and having poor cleaning effects. In this embodiment, a third nozzle 340 is further installed on the cyclone separator body 370. The third nozzle 340 is fixedly installed on the circumferential outer wall of the cyclone separator body 370 and is arranged to penetrate the side wall. It is used to spray the filter cloth 320 installed on the inner wall of the cyclone separator body 370, making it easier to blow off the activated carbon powder on the filter cloth 320.

[0057] More optimally, the third nozzle 340 includes a plurality of third nozzles 340, which are evenly spaced and arranged on the side wall of the cyclone separator body 370. By optimizing the layout of the third nozzles 340, it is helpful to improve the spraying efficiency and effect. In addition, the device of this embodiment also includes an activated carbon powder collection hopper 350, which is detachably mounted on the bottom of the cyclone separator body 370. The activated carbon powder collection hopper 350 is processed into a cylindrical shape, and its diameter is the same as the diameter of the bottom of the cyclone separator. Specifically, the size of the device can be determined according to actual needs. To facilitate subsequent experiments, the specific volume of the activated carbon powder collection hopper 350 in this embodiment is 10m 3 , 20 air nozzles 340 are evenly distributed on the side wall of the cyclone separator body 370.

[0058] The present invention provides a method for reducing dioxin emissions from organic coating pyrolysis flue gas, which uses the above-mentioned emission reduction device to treat dioxins generated during the pyrolysis of the organic coating, and comprises the following steps:

[0059] (1) The waste material containing the organic coating is pyrolyzed in the pyrolysis furnace body 110. During the pyrolysis process, activated carbon powder and inhibitor are sprayed into the pyrolysis furnace. The flow rate Q of the sprayed inhibitor satisfies the following relationship: Q = 247t 2 -348.8t+171.03; where Q is in L / h and t is the pyrolysis time in h.

[0060] (2) The pyrolysis flue gas enters the flue gas outlet pipe and begins to be sprayed with the inhibitor. The pyrolysis flue gas carrying the inhibitor enters the cyclone separator body 370 of the tar separation unit 300 for treatment. The treated flue gas enters the adsorption unit 400 for adsorption treatment.

[0061] (3) The third nozzle 340 is turned on to spray the filter cloth 320 on the side wall of the cyclone separator body 370, and the activated carbon powder collecting hopper 350 collects the activated carbon powder adsorbed with tar that is blown down.

[0062] The emission reduction device was used to conduct experiments to test the emission reduction performance of the emission reduction device. Specifically, 2 tons of scrap copper enameled wire was placed in an organic coating pyrolysis unit for 2 hours. The flow rate of the dioxin inhibitor sprayed during the pyrolysis process met the following relationship: Q = 247t 2 -348.8t+171.03 (Q: L / h, t: h). The dioxin sampling device recommended in HJ 77.2-2008 was used to sample the dioxins generated during the entire pyrolysis process. After the sampling was completed, the collected samples were analyzed using a high-resolution magnetic mass spectrometry system. The results are shown in Table 1.

[0063] Comparative Example 1

[0064] This comparative example differs from Example 1 in that a conventional pyrolysis apparatus was used, directly placing 2 tons of scrap copper enameled wire into the pyrolysis furnace for 2 hours. No dioxin inhibitors were sprayed during the pyrolysis process, tar in the flue gas was not separated, and flue gas adsorption was not performed. Dioxins generated throughout the pyrolysis process were sampled using the dioxin sampling device recommended in HJ 77.2-2008. After sampling, the collected samples were analyzed using a high-resolution magnetic mass spectrometer. The results are shown in Table 1.

[0065] Comparative Example 2

[0066] This comparative example uses the emission reduction device of Example 1. The difference from Example 1 is that during the test, the dioxin spraying flow rate during the pyrolysis process was 50 L / h. The dioxin sampling device recommended in HJ 77.2-2008 was placed at the flue gas duct outlet after the adsorption unit to sample the dioxins generated during the entire pyrolysis process. After the sampling was completed, the collected samples were analyzed using a high-resolution magnetic mass spectrometry system. The results are shown in Table 1.

[0067] Comparative Example 3

[0068] This comparative example uses the emission reduction device of Example 1. The difference from Example 1 is that during the test, the dioxin spraying flow rate during the pyrolysis process was 20 L / h, and the dioxin sampling device recommended in HJ 77.2-2008 was used to sample the dioxins generated during the entire pyrolysis process. After the sampling was completed, the collected samples were analyzed using a high-resolution magnetic mass spectrometry system. The results are shown in Table 1.

[0069] Comparative Example 4

[0070] The emission reduction device in this comparative example is basically the same as that in Example 1. The difference from Example 1 is that this comparative example does not have a tar separation unit, and the pyrolysis flue gas directly enters the adsorption unit from the organic coating pyrolysis unit through the flue gas duct.

[0071] The emission reduction effect of the emission reduction device was tested. 2 tons of scrap copper enameled wire was placed in the organic coating pyrolysis unit for 2 hours. The flow rate of the dioxin inhibitor sprayed during the pyrolysis process met the following relationship: Q = 247t 2 -348.8t+171.03 (Q: L / h, t: h). The dioxin sampling device recommended in HJ 77.2-2008 was used to sample the dioxins generated during the entire pyrolysis process. After the sampling was completed, the collected samples were analyzed using a high-resolution magnetic mass spectrometry system. The results are shown in Table 1.

[0072] Comparative Example 5

[0073] The emission reduction device in this comparative example is essentially the same as that in Example 1, except that it does not include an adsorption unit. The pyrolysis flue gas flows from the organic coating pyrolysis unit through the flue gas inlet channel into the tar separation unit before exiting through the flue gas outlet channel. The emission reduction effect of this device was tested by placing 2 tons of scrap copper enameled wire in the organic coating pyrolysis unit for 2 hours. The flow rate of the dioxin inhibitor sprayed during the pyrolysis process satisfied the following equation: Q = 247t 2 -348.8t+171.03 (Q: L / h, t: h). The dioxin sampling device recommended in HJ 77.2-2008 was used to sample the dioxins generated during the entire pyrolysis process. After the sampling was completed, the collected samples were analyzed using a high-resolution magnetic mass spectrometry system. The results are shown in Table 1.

[0074] Table 1 Dioxin emission concentrations and dioxin inhibitor dosages in Example 1 and Comparative Examples 1 to 5

[0075]

[0076] By analyzing the indicator data in Table 1, the following conclusions are drawn:

[0077] (1) Comparative Example 1 was compared with Example 1. In the case of direct pyrolysis of waste copper enameled wire in a pyrolysis furnace, no dioxin inhibitor was sprayed during the pyrolysis process, no tar in the pyrolysis flue gas was separated, and no adsorption of the flue gas was performed, the dioxin emission concentration increased by 5.219 ng TEQ / m 3 , does not meet national emission standards;

[0078] (2) Comparative Example 2 is compared with Example 1. The spray flow rate of the dioxin inhibitor is 50 L / h, the amount of the dioxin inhibitor is increased by 52.2 L, the dioxin emission concentration meets the national emission standards, and the coating removal rate is reduced by 7.8%;

[0079] (3) Comparative Example 3 is compared with Example 1. The spraying flow rate of the dioxin inhibitor is 20 L / h, the amount of dioxin inhibitor used is reduced by 7.8 L, and the emission concentration of dioxins increases by 0.772 ng TEQ / m 3 , does not meet national emission standards;

[0080] (4) Comparison of Example 4 with Example 1 shows that the dioxin emission reduction device does not have a tar separation unit and does not separate the tar in the pyrolysis flue gas. The dioxin emission concentration increases by 1.576 ng TEQ / m 3 , does not meet national emission standards;

[0081] (5) Comparative Example 5 is compared with Example 1. In the dioxin emission reduction device, no adsorption unit is provided, and no adsorption is performed on the pyrolysis flue gas after tar separation. The dioxin emission concentration increases by 0.657 ng TEQ / m 3 , does not meet national emission standards;

[0082] The applicant's research has found that the coordination of the inhibitor spray unit, tar separation unit, and adsorption unit is crucial for reducing dioxin emissions during the pyrolysis process of organic coatings. Extensive experiments have demonstrated that dioxin inhibitors cannot be simply sprayed continuously at a specific flow rate during the pyrolysis process of organic coatings. The spray flow rate of the dioxin inhibitor should match the dioxin emission pattern during the pyrolysis process of the organic coating. If the dioxin inhibitor spray flow rate is too high, while dioxin emissions can be effectively reduced, the removal rate of the organic coating will decrease. This is because the initial pyrolysis process is a heating process. Spraying a large amount of inhibitor at this time will reduce the heating rate, resulting in incomplete pyrolysis of the organic coating and a decrease in the removal rate of the organic coating. Furthermore, a large amount of dioxin inhibitor will be wasted. If the dioxin inhibitor spray flow rate is too low, the inhibition level will be insufficient, and dioxin emissions cannot be effectively reduced.

[0083] Since the emission characteristics of dioxins during the pyrolysis of organic coatings are difficult to detect, and dioxins are a type of VOCs, the change in the emission concentration of VOCs during the pyrolysis of organic coatings over time can be detected. The emission pattern of dioxins can be reflected by the emission pattern of VOCs. The applicant fitted the curve of the change in the emission concentration of VOCs during the pyrolysis of organic coatings over time, and the fitting results are as follows: Figure 4 As shown, based on the emission law and fitting results, the applicant calculated the relationship between the dioxin inhibitor spray flow rate and the pyrolysis time during the pyrolysis process of the organic coating: Q = 247t 2 -348.8t+171.03(Q: L / h, t: h). The spraying flow rate of dioxin inhibitors in the pyrolysis process of organic coatings is controlled according to this formula. This not only achieves dioxin emission reduction and makes the dioxin emission concentration meet the national standard, but also reduces the spraying amount of dioxin inhibitors in the pyrolysis process, saving costs.

[0084] In addition, the applicant has found through long-term experiments that dioxins are mainly formed on the surface of tar during the pyrolysis process of organic coatings. Therefore, removing tar from pyrolysis flue gas is very important for reducing dioxin emissions. Figure 2 Figure 3As shown in the figure, after the pyrolysis flue gas enters the tar separation unit tangentially, the flue gas flow changes from linear motion to circular motion, with the rotating airflow flowing downward in a spiral along the wall. Under the action of centrifugal force, the tar in the flue gas is thrown toward the filter cloth layer on the wall surface. The tar has a certain viscosity and adheres to the activated carbon on the filter cloth surface, thus separating the tar from the flue gas. The rotating downward airflow continuously flows into the center of the cyclone separator during its descent, forming a centripetal radial airflow, forming an upward rotating internal vortex. The internal and external vortices rotate in the same direction, and the flue gas flow flows out from the upper flue gas outlet pipe. After the activated carbon powder 330 has adsorbed tar to saturation, the static electricity on the filter cloth 320 is discharged, and the electrostatic adsorption between the activated carbon powder 330 and the filter cloth 320 disappears. The activated carbon powder 330 is no longer attached to the filter cloth 320 by electrostatic adsorption. Air is sprayed onto the filter cloth 320 through the third nozzle 340, causing the activated carbon powder 330 attached to the filter cloth 320 to fall off and fall into the activated carbon powder collection hopper 350. The activated carbon powder 330 in the activated carbon powder collection hopper 350 can be sprayed into the organic coating pyrolysis unit 100 through the activated carbon powder nozzle 120 during the pyrolysis process for combustion, thereby decomposing dioxins on the tar surface and providing heat for the pyrolysis of the organic coating.

[0085] Example 2

[0086] The dioxin emission reduction device of this embodiment is the same as that of Example 1. The emission reduction effect of the emission reduction device was tested. 1.5 tons of scrap copper enameled wire was placed in the organic coating pyrolysis unit for 2 hours. After 15 minutes of pyrolysis, the dioxin inhibitor was sprayed until the pyrolysis was completed. The spraying flow rate of the dioxin inhibitor satisfied the following relationship: Q = 247 tons 2 -348.8t+171.03 (Q: L / h, t: h). The dioxin inhibitor was a 9.1% urea solution. The dioxin sampling method recommended in HJ 77.2-2008 was placed at the flue gas duct outlet after the adsorption unit to sample the dioxins generated during the entire pyrolysis process. After sampling, the collected samples were analyzed using a high-resolution magnetic mass spectrometry system. The dioxin emission concentration was 0.079ng TEQ / m 3 , in line with national emission standards, the coating removal rate is 99.6%.

[0087] Example 3

[0088] The dioxin emission reduction device of this embodiment is the same as that of Example 1. The emission reduction effect of the emission reduction device was tested. 2.5 tons of scrap copper enameled wire was placed in the organic coating pyrolysis unit for 2 hours. After 15 minutes of pyrolysis, the dioxin inhibitor was sprayed until the pyrolysis was completed. The spraying flow rate of the dioxin inhibitor satisfied the following relationship: Q = 247 tons 2-348.8t+171.03 (Q: L / h, t: h). The dioxin inhibitor was a 9.1% urea solution. The dioxin sampling method recommended in HJ 77.2-2008 was placed at the flue gas duct outlet after the adsorption unit to sample the dioxins generated during the entire pyrolysis process. After sampling, the collected samples were analyzed using a high-resolution magnetic mass spectrometry system. The dioxin emission concentration was 0.084ng TEQ / m 3 , in line with national emission standards, the coating removal rate is 99.3%.

[0089] The present invention has been described in detail above with reference to specific exemplary embodiments. However, it should be understood that various modifications and variations may be made without departing from the scope of the present invention as defined by the appended claims. The detailed description and accompanying drawings should be considered merely illustrative and not restrictive, and any such modifications and variations, if any, are intended to fall within the scope of the present invention as described herein. In addition, the background art is intended to illustrate the current status and significance of the present technology and is not intended to limit the present invention or the application and fields of application of the present invention.

[0090] More specifically, although exemplary embodiments of the present invention have been described herein, the present invention is not limited to these embodiments, but rather includes any and all embodiments that may be recognized by those skilled in the art based on the foregoing detailed description, such as combinations between the various embodiments, adaptations, and / or substitutions. The limitations in the claims are to be interpreted broadly based on the language used in the claims and are not limited to the examples described in the foregoing detailed description or during the prosecution of this application, which examples should be considered non-exclusive. Any steps recited in any method or process claim may be performed in any order and are not limited to the order set forth in the claims. Therefore, the scope of the invention should be determined solely by the appended claims and their legal equivalents, rather than by the description and examples given above.

Claims

1. A device for reducing dioxin emissions from organic coating pyrolysis flue gas, comprising an organic coating pyrolysis unit (100) and an adsorption unit (400), characterized in that: The invention also includes an inhibitor spraying unit (200) and a tar separation unit (300), wherein the organic coating pyrolysis unit (100) is connected to the tar separation unit (300) via a flue gas outlet pipe, and the flue gas outlet pipe and the organic coating pyrolysis unit (100) are respectively connected to the inhibitor spraying unit (200); the flue gas outlet of the tar separation unit (300) is connected to the adsorption unit (400) via a pipeline; The tar separation unit (300) includes a cyclone separator body (370), the cyclone separator body (370) is provided with a cyclone separator feed port (310) and a cyclone separator discharge port (360), the cyclone separator feed port (310) is connected to a flue gas outlet pipe, and the cyclone separator discharge port (360) is connected to an adsorption unit (400) through a pipeline; A filter cloth (320) is fixedly mounted on the circumferential inner wall of the cyclone separator body (370), and a layer of activated carbon powder (330) is adsorbed on the surface of the filter cloth (320) through an electrostatic generator.

2. The device for reducing dioxin emissions from pyrolysis flue gas of an organic coating according to claim 1, characterized in that: The inhibitor spraying unit (200) includes a first nozzle (241), a second nozzle (242) and an inhibitor storage tank (210), wherein the first nozzle (241) is arranged directly above the pyrolysis furnace body (110) of the organic coating pyrolysis unit (100), and the first nozzle (241) is connected to the inhibitor storage tank (210) through a pipeline, and the second nozzle (242) is arranged in the flue gas outlet pipe and connected to the inhibitor storage tank (210).

3. The device for reducing dioxin emissions from organic coating pyrolysis flue gas according to claim 2, characterized in that: A first jet pump (231) and a first flow valve (221) are provided on a pipeline connecting the first nozzle (241) and the inhibitor storage tank (210).

4. A device for reducing dioxin emissions from organic coating pyrolysis flue gas according to any one of claims 1 to 3, characterized in that: It also includes an activated carbon powder nozzle (120), which is arranged on the top of the pyrolysis furnace body (110) of the organic coating pyrolysis unit (100).

5. The device for reducing dioxin emissions from organic coating pyrolysis flue gas according to claim 4, characterized in that: The invention also includes a third nozzle (340) and an activated carbon powder collecting hopper (350). The third nozzle (340) is fixedly mounted on the circumferential outer wall of the cyclone separator body (370) and penetrates the outer wall of the cyclone separator body (370). The activated carbon powder collecting hopper (350) is detachably mounted on the bottom of the cyclone separator body (370).

6. The device for reducing dioxin emissions from organic coating pyrolysis flue gas according to claim 5, characterized in that: The third nozzles (340) include a plurality of nozzles, which are evenly spaced and arranged on the side wall of the cyclone separator body (370) for spraying the activated carbon powder on the filter cloth (320).

7. A method for reducing dioxin emissions from pyrolysis flue gas of an organic coating, characterized by: The method of using the emission reduction device according to any one of claims 5 or 6 to treat dioxins generated during the pyrolysis of an organic coating comprises the following steps: (1) The waste material containing the organic coating is pyrolyzed in the pyrolysis furnace body (110), and activated carbon powder and inhibitor are sprayed into the pyrolysis furnace during the pyrolysis process; (2) The pyrolysis flue gas enters the flue gas outlet pipe and begins to be sprayed with an inhibitor. The pyrolysis flue gas carrying the inhibitor enters the cyclone separator body (370) of the tar separation unit (300) for treatment. The treated flue gas enters the adsorption unit (400) for adsorption treatment. (3) The third nozzle (340) is turned on to spray the filter cloth (320) on the side wall of the cyclone separator body (370), and the activated carbon powder collecting hopper (350) collects the activated carbon powder adhering to the tar that is blown down.

8. The method for reducing dioxin emissions from pyrolysis flue gas of an organic coating according to claim 7, characterized in that: During the pyrolysis process, the flow rate Q of the sprayed inhibitor satisfies the following relationship: Q=247t 2 -348.8t+171.03 Wherein, the unit of Q is L / h, and t is the pyrolysis time in h.

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