A kind of equipment and method for treating flue gas with polymorphic organic pollutants

Abstract

The present invention discloses a device and method for treating flue gas containing polymorphic organic pollutants, which belongs to the field of environmental protection technology. The device is equipped with a coarse diameter collecting bundle in the front section of the demister, and a small diameter collecting bundle in the rear section, and the distance between modules of the collecting bundle grid is set to be as small as possible when it is greater than 3 times the diameter of droplets and particulate matter, so as to reduce the volume of the equipment and save costs. The present invention is a modular structure, and each module is a collecting bundle grid. The grid collecting bundle is used to block, adsorb and capture liquid organic matter, and the flue gas is treated by combining activated carbon to adsorb gaseous organic matter. The treatment effect is good with segmented capture. It can realize unpowered demisting and dust removal, and utilize the inertia and gravity performance of the airflow, without generating more energy consumption and secondary pollutants.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection, and in particular relates to a device and method for treating flue gas containing polymorphic organic pollutants. Background Art

[0002] Flue gas containing organic pollutants is often a mixed flue gas in which solid, liquid and gaseous forms coexist, which brings difficulties to flue gas treatment. At present, there are many treatment methods, such as electrostatic adsorption, spray capture, centrifugal capture, etc. Electrostatic adsorption is often difficult to capture because organic droplets or particles are very small, and gaseous VOC cannot be captured by electrostatic method. If activated carbon is used for adsorption at the rear, the pores of activated carbon will be quickly blocked due to too many small droplets escaping from the front. The activated carbon is replaced too frequently and the cost is too high. The spray capture method generally uses water for spraying. Water does not wet many organic substances, and the capture efficiency is too low. The capture efficiency cannot meet environmental protection requirements at all. Spraying with water cannot capture gaseous organic matter, and the sprayed flue gas often carries a large number of droplets, which cannot be adsorbed by activated carbon. Therefore, it cannot be used for polymorphic organic matter. Centrifugal capture has a certain capture effect on liquids and solids, but the amount of small droplets escaping is still relatively large. If activated carbon is used to adsorb gaseous organic matter at the rear, the pores of the activated carbon will quickly become clogged, the replacement frequency is too high, the operating cost is too high, and the maintenance volume is too large, so it is basically not applicable. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a device and method for treating flue gas with polymorphic organic pollutants, which uses a grid capture beam to block and adsorb liquid-specific organic matter, combined with activated carbon to adsorb gaseous organic matter for flue gas treatment.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A device for treating flue gas containing polymorphic organic pollutants, comprising a flue gas duct 1, a uniform distribution chamber 2, a pressure equalizing orifice plate 3, a collection chamber 4, a collection beam grid 5, a liquid collecting tank 6, a liquid drain pipe 7, a connecting chamber 8, an adsorption chamber 9 and a smoke exhaust port 10;

[0006] The smoke duct 1 is connected to the front port of the uniform distribution chamber 2, the rear end of the uniform distribution chamber 2 is connected to the front end of the collection chamber 4, a pressure equalizing orifice plate 3 is provided between the uniform distribution chamber 2 and the collection chamber 4, the rear end of the collection chamber 4 is connected to the connecting chamber 8, the rear port of the connecting chamber 8 is connected to the adsorption chamber 9, and the rear end of the adsorption chamber 9 is provided with a smoke exhaust port 10;

[0007] The collection chamber 4 is composed of a collection beam grid 5 evenly distributed inside, a liquid collecting tank 6 and a liquid drain pipe 7 arranged at the bottom.

[0008] The capture beam grid 5 is obtained by longitudinally winding wires, and the wires are made of wettable materials with low surface tension with the captured organic matter, including metal wires, cotton wires, chemical fiber wires or mineral wool wires, etc.; the diameter of the wires is larger than the diameter of the maximum intercepted droplets and solid particles; the distance between the wires is larger than 3 times the diameter of the maximum intercepted droplets and solid particles. The smaller the wire spacing, the higher the interception and capture efficiency, the smaller the volume of the equipment, but the greater the resistance;

[0009] The capture beam grid 5 is a modular structure, and the number of modules of the capture beam grid 5 is several, and the distance between them is greater than 3 times the diameter of the maximum droplet and particle. The capture beam grid 5 is tilted and has a certain angle with the horizontal plane, and the angle is 30-150°. The distance between modules of the capture beam grid 5 is greater than 3 times the diameter of the maximum droplet and particle. The smaller the distance, the smaller the volume of the equipment, but the greater the resistance; the more capture beam layers there are, the higher the interception and capture efficiency, but the larger the volume of the equipment will be, and the resistance will also increase.

[0010] The angle between the capture beam grid and the horizontal plane is 90°.

[0011] The adsorption chamber 9 is filled with active adsorption materials, including adsorption materials such as activated carbon or pumice.

[0012] A method for treating flue gas containing polymorphic organic pollutants, using the above-mentioned device for treating flue gas containing polymorphic organic pollutants, the method comprises the following steps:

[0013] Step 1: The smoke is introduced into the uniform distribution chamber 2 through the smoke duct 1, the smoke is evenly diffused in the uniform distribution chamber 2, and then enters the capture chamber 4 after being pressure-equalized through the pressure-equalizing orifice plate 3;

[0014] Step 2: The smoke passes through the capture beam grid 5 in the capture chamber 4 to capture liquid and solid. The liquid and solid substances captured by the capture beam grid 5 flow downward, enter the liquid collecting tank 6, and are discharged through the drain pipe 7;

[0015] Step 3: The gaseous organic matter in the flue gas that is not captured in the capture chamber 4 enters the adsorption chamber 9 through the connecting chamber 8. The active adsorption material in the adsorption chamber 9 adsorbs the gaseous organic matter in the flue gas, and finally the clean air after adsorption is discharged through the exhaust port 10;

[0016] Step 4: When the collection beam grid 5 is clogged due to adhesion and scaling, high-temperature gas or steam is introduced to heat the adhesion and scaling to flow to the liquid collecting tank 6 and be discharged from the drain pipe 7; or the cover of the collection chamber 4 is opened, the collection beam grid 5 is taken out, and offline cleaning is performed.

[0017] The governance principle of the method of the present invention:

[0018] The method of the present invention is to select a material with good wettability with the organic matter in the treated flue gas to manufacture a collection beam grid, arrange it in a special collection chamber, and allow the flue gas to generate turbulent collision when passing through the collection beam grid. The organic droplets are adsorbed and captured when they collide with the material wire with good wettability, and the particulate organic matter will be adsorbed and captured by the liquid organic matter on the wire. When a certain amount is accumulated, it will flow down into the liquid collection tank at the bottom of the equipment under the action of gravity. When a certain amount is accumulated, it will be discharged through the set drain pipe. The droplets entrained in the flue gas will generate impact turbulence when passing through each layer of the collection beam grid, and the droplets will also collide with each other and merge to grow, and some particulate matter will adhere to the droplets. The density of droplets and particles is much greater than that of gas. When the airflow collides with the capture beam, the kinetic energy and inertia of the droplets are large. When the airflow collides with the interception capture beam, the droplets and particles will break through the air film and collide with the interception capture beam. Since the selected capture beam material is a material with good wettability with the droplets, the droplets will be adsorbed on the surface of the capture beam. Since a certain amount of droplets will gather on the surface of the capture beam material, these droplets will adsorb particulate organic matter. Each time the airflow contacts the capture beam, it is a very thin layer, and only part of it can be captured each time. Large particles are easy to be intercepted, and small particles are easy to escape, so multiple captures are required. The larger the droplets and particles, the greater the kinetic energy. When the airflow is blocked and changes direction, the droplets and particles will break through the air film due to their inertia and collide with the interception capture beam, and be intercepted, adsorbed and captured. The larger the diameter of the droplets, the stronger their ability to break through the air film and the easier they are to be adsorbed. On the contrary, the smaller the droplets, the smaller the kinetic energy, the worse the ability to break through the air film, and the less likely they are to be adsorbed and captured; the faster the flue gas flow rate, the greater the kinetic energy of the droplets, and the easier it is to capture the droplets. However, if the air flow rate is too fast, it is easy to carry away the droplets or particles gathered on the wire, forming droplet escape. The flue gas flow rate is fast, the system resistance is large, and the energy consumption is large. After the flue gas passes through the capture beam grid, the air flow will form turbulence and collide with the capture beam grid behind it in a disorderly manner, and be intercepted again. The more times it is intercepted, the higher the demisting efficiency. The greater the density of the grid capture beam, the greater the probability of the droplets being intercepted. The droplet interception efficiency is positively correlated with the quotient of the sum of the surface areas of the capture beams divided by the cross-sectional area of ​​the airflow between the capture beams, and is positively correlated with the number of interceptions. Under the condition of constant equipment geometry and constant equipment resistance, the thinner the interception capture beam of the grid, the more wires are arranged in a certain space, the larger the sum of the wire surface areas, the more opportunities for the droplets to collide with the wires, and the greater the probability of being captured. The droplets have a certain inertia when flowing with the smoke. When colliding with the capture beam, the droplets have an escape force in addition to the adsorption force. They can only be adsorbed when the adsorption force is greater than the escape force. The adsorption force is related to the wettability of the capture beam material and the captured droplets, and also to the adsorption area of ​​the capture beam. The thicker the diameter of the capture beam, the greater the adsorption force. Conversely, the smaller it is. Therefore, the diameter of the capture beam cannot be too thin. Otherwise, the droplets cannot be captured due to insufficient adsorption force, causing the droplets to escape. Therefore, the diameter of the interception wire is required to be larger than the maximum interception droplet diameter.To solve this problem, a coarse diameter collection beam is arranged in the front section of the demister, and a small diameter collection beam is arranged in the rear section. The present invention is a modular structure, each module is a collection beam grid, which can achieve unpowered demisting and dust removal, and utilizes the inertia and gravity performance of the airflow, without generating more energy consumption and generating secondary pollutants.

[0019] Compared with the prior art, the method and device for treating flue gas containing polymorphic organic pollutants of the present invention have the following beneficial effects:

[0020] 1. Since the capture beam grid at the front end has captured the liquid-based organic matter, the problem of poisoning caused by clogging of the holes of the active adsorption material is avoided, and the service life of the adsorption material can be greatly extended.

[0021] Second, the smaller the distance between the capture beams, the larger the effective capture area and the higher the capture efficiency, but the greater the equipment resistance, the easier it is to form a system blockage. Too large a distance will reduce the specific surface area captured by the capture beam, reduce the capture function per unit equipment volume, and require increasing the number of passes of the capture beam grid, increasing the equipment length, and increasing investment. Therefore, the distance between the modules of the capture beam grid 5 is set to be greater than 3 times the diameter of the droplets and particles, and is minimized to reduce the equipment volume and save costs.

[0022] 3. The present invention utilizes the grid capture beam to block and adsorb the inherent organic matter in the liquid, and combines it with the activated carbon to adsorb the gaseous organic matter to treat the flue gas, with segmented capture and good treatment effect.

[0023] 4. The capture beam grid captures liquid-based organic matter by bonding and adsorption, and the adsorbed liquid and solid matter will be self-cleared by gravity, which will not increase system resistance. The system resistance is much smaller than filtration interception, and gravity self-cleaning can ensure continuous and stable operation of the system.

[0024] 5. The equipment of the present invention has stable operation, simple maintenance, low investment, low operating cost, and can meet environmental protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a front view of a device for treating flue gas containing polymorphic organic pollutants according to an embodiment of the present invention;

[0026] Figure 2 A top view of a device for treating flue gas containing polymorphic organic pollutants according to an embodiment of the present invention;

[0027] Figure 3 It is a left view of the device for treating flue gas with polymorphic organic pollutants according to an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the capture bundle structure of the multi-state organic pollutant flue gas treatment equipment according to an embodiment of the present invention; wherein:

[0029] 1-smoke duct, 2-uniform distribution chamber, 3-equal pressure orifice plate, 4-capture chamber, 5-capture beam grid, 6-liquid collecting tank, 7-liquid drain pipe, 8-connection chamber, 9-adsorption chamber, 10-smoke exhaust port. DETAILED DESCRIPTION

[0030] The following is a combination of specific implementation cases and attached Figure 1 The present invention is further described below, but the present invention is not limited to these embodiments.

[0031] Example 1

[0032] The canteen smoke of a certain unit originally used electrostatic degreasing mist at the front end and activated carbon adsorption at the back end. When the smoke humidity was high, explosions often occurred, causing damage to the equipment. In addition, due to the unstable degreasing effect, the life of the activated carbon at the back end was too short, and the activated carbon became ineffective in less than two days. A large amount of oil stains adhered to the surface of the activated carbon. In order to solve the above problems, the equipment of the present invention was used.

[0033] The maximum flue gas flow rate is 8,000 cubic meters per hour, the equipment is 4 meters long, the flue gas flow rate is 3 meters per second, and the equipment cross-sectional area is 1 square meter.

[0034] A device for treating flue gas containing polymorphic organic pollutants, the front view of which is shown as follows Figure 1 As shown, the top view is Figure 2 As shown, the left view is Figure 3 The schematic diagram of the trapping beam structure is shown in Figure 4 As shown, it includes a smoke duct 1, a uniform distribution chamber 2, a pressure equalizing orifice plate 3, a collection chamber 4, a collection beam grid 5, a liquid collecting tank 6, a liquid drain pipe 7, a connecting chamber 8, an adsorption chamber 9 and a smoke exhaust port 10;

[0035] The smoke duct 1 is connected to the front port of the uniform distribution chamber 2, the rear end of the uniform distribution chamber 2 is connected to the front end of the collection chamber 4, a pressure equalizing orifice plate 3 is provided between the uniform distribution chamber 2 and the collection chamber 4, the rear end of the collection chamber 4 is connected to the connecting chamber 8, the rear port of the connecting chamber 8 is connected to the adsorption chamber 9, and the rear end of the adsorption chamber 9 is provided with a smoke exhaust port 10;

[0036] The collection chamber 4 is composed of a collection beam grid 5 evenly distributed inside, a liquid collecting tank 6 and a liquid drain pipe 7 arranged at the bottom.

[0037] The capture beam grid 5 is arranged vertically;

[0038] The capture beam grid 5 is a modular structure, the number of modules of the capture beam grid 5 is several, and the distance between the modules of the capture beam grid 5 is 20 mm;

[0039] The wire material of the capture beam grid 5 is ordinary carbon steel wire with a diameter of 1.2 mm;

[0040] The adsorption chamber 9 is filled with activated carbon.

[0041] A method for treating flue gas containing polymorphic organic pollutants, using the above-mentioned device for treating flue gas containing polymorphic organic pollutants, the method comprises the following steps:

[0042] Step 1: The furnace hood fume is introduced into the uniform distribution chamber 2 through the fume duct 1, and the fume is evenly diffused in the uniform distribution chamber 2, and then enters the capture chamber 4 after being pressure-equalized through the pressure-equalizing orifice plate 3;

[0043] Step 2: The smoke passes through the capture beam grid 5 in the capture chamber 4 to capture liquid and solid. The liquid and solid substances captured by the capture beam grid 5 flow downward, enter the liquid collecting tank 6, and are discharged through the drain pipe 7;

[0044] Step 3: The gaseous organic matter not captured in the capture chamber 4 enters the adsorption chamber 9 along with the flue gas through the connecting chamber 8. The activated carbon in the adsorption chamber 9 adsorbs and captures the gaseous organic matter in the flue gas. Finally, the clean air after adsorption is discharged through the exhaust port 10.

[0045] Step 4: When the collection beam grid 5 is clogged due to adhesion and scaling, high-temperature gas or steam is introduced to heat the adhesion and scaling to flow to the liquid collecting tank 6 and be discharged from the drain pipe 7; or the cover of the collection chamber 4 is opened, the collection beam grid 5 is taken out, and offline cleaning is performed.

[0046] In this embodiment, since the capture beam grid at the front end has captured the oil smoke droplets and particulate matter, the problem of activated carbon being blocked and causing poisoning is avoided, and the service life of the activated carbon is greatly extended.

[0047] When this embodiment is running for a long time, the collection bundle adhesive will scale, especially in winter when the temperature is low. Since the system is intermittent, when the resistance is large, open the cover of the collection chamber, take out the collection bundle grid for offline cleaning, install it back into the system after cleaning, close the cover and continue to work; the drain pipe is opened regularly to discharge the accumulated waste liquid. The equipment has been running for 8 months and everything is normal. The activated carbon only needs to be replaced once a month.

[0048] In this embodiment, after three tests and one month of operation without replacing the activated carbon, the non-methane VOC emission was less than 1.0 mg / m 3 , meeting local emission standards.

[0049] Example 2

[0050] A barbecue restaurant used electrostatic degreasing mist at the front end and activated carbon adsorption at the back end. Due to the unstable degreasing effect, the life of the activated carbon at the back end was too short, and the activated carbon became ineffective in less than two days. A large amount of oil stains adhered to the surface of the activated carbon. In order to solve the above problems, the equipment of the present invention was used.

[0051] The flue gas volume is 2000 cubic meters per hour, the equipment is 4 meters long, the flue gas velocity is 1.3 meters per second, and the equipment cross-sectional area is 0.4 square meters.

[0052] A device for treating flue gas containing polymorphic organic pollutants, the front view of which is shown as follows Figure 1 As shown, the top view is Figure 2 As shown, the left view is Figure 3 The schematic diagram of the trapping beam structure is shown in Figure 4 As shown, it includes a smoke duct 1, a uniform distribution chamber 2, a pressure equalizing orifice plate 3, a collection chamber 4, a collection beam grid 5, a liquid collecting tank 6, a liquid drain pipe 7, a connecting chamber 8, an adsorption chamber 9 and a smoke exhaust port 10;

[0053] The smoke duct 1 is connected to the front port of the uniform distribution chamber 2, the rear end of the uniform distribution chamber 2 is connected to the front end of the collection chamber 4, a pressure equalizing orifice plate 3 is provided between the uniform distribution chamber 2 and the collection chamber 4, the rear end of the collection chamber 4 is connected to the connecting chamber 8, the rear port of the connecting chamber 8 is connected to the adsorption chamber 9, and the rear end of the adsorption chamber 9 is provided with a smoke exhaust port 10;

[0054] The collection chamber 4 is composed of a collection beam grid 5 evenly distributed inside, a liquid collecting tank 6 and a liquid drain pipe 7 arranged at the bottom.

[0055] The capture beam grid 5 is arranged vertically;

[0056] The capture beam grid 5 is a modular structure, the number of modules of the capture beam grid 5 is several, and the distance between the modules of the capture beam grid 5 is 15 mm;

[0057] The wire material of the capture beam grid 5 is ordinary carbon steel wire with a diameter of 1 mm;

[0058] The adsorption chamber 9 is filled with activated carbon.

[0059] A method for treating flue gas containing polymorphic organic pollutants, using the above-mentioned device for treating flue gas containing polymorphic organic pollutants, the method comprises the following steps:

[0060] Step 1: The furnace hood fume is introduced into the uniform distribution chamber 2 through the fume duct 1, and the fume is evenly diffused in the uniform distribution chamber 2, and then enters the capture chamber 4 after being pressure-equalized through the pressure-equalizing orifice plate 3;

[0061] Step 2: The smoke passes through the capture beam grid 5 in the capture chamber 4 to capture liquid and solid. The liquid and solid substances captured by the capture beam grid 5 flow downward, enter the liquid collecting tank 6, and are discharged through the drain pipe 7;

[0062] Step 3: The gaseous organic matter not captured in the capture chamber 4 enters the adsorption chamber 9 along with the flue gas through the connecting chamber 8. The activated carbon in the adsorption chamber 9 adsorbs and captures the gaseous organic matter in the flue gas. Finally, the clean air after adsorption is discharged through the exhaust port 10.

[0063] Step 4: When the collection beam grid 5 is clogged due to adhesion and scaling, high-temperature gas or steam is introduced to heat the adhesion and scaling to flow to the liquid collecting tank 6 and be discharged from the drain pipe 7; or the cover of the collection chamber 4 is opened, the collection beam grid 5 is taken out, and offline cleaning is performed.

[0064] In this embodiment, since the capture beam grid at the front end has captured the oil smoke droplets and particulate matter, the problem of activated carbon being blocked and causing poisoning is avoided, and the service life of the activated carbon is greatly extended.

[0065] When this embodiment is running for a long time, the collection bundle adhesive will scale, especially in winter when the temperature is low. Since the system is intermittent, when the resistance is large, open the cover of the collection chamber, take out the collection bundle grid for offline cleaning, install it back into the system after cleaning, close the cover and continue to work; the drain pipe is opened regularly to discharge the accumulated waste liquid. The equipment has been running for 10 months and everything is normal. The activated carbon only needs to be replaced once a month.

[0066] In this embodiment, after two tests and one month of operation without replacing the activated carbon, the non-methane VOC emission was less than 1.0 mg / m 3 , meeting local emission standards.

Claims

1. A device for treating flue gas containing polymorphic organic pollutants, characterized in that: It includes a smoke duct, a uniform distribution chamber, a pressure equalizing orifice plate, a collection chamber, a collection beam grid, a liquid collecting tank, a liquid drain pipe, a connecting chamber, an adsorption chamber and a smoke exhaust port; The smoke duct is connected to the front port of the uniform distribution chamber, the rear end of the uniform distribution chamber is connected to the front end of the collection chamber, a pressure equalizing orifice plate is provided between the uniform distribution chamber and the collection chamber, the rear end of the collection chamber is connected to the connecting chamber, the rear port of the connecting chamber is connected to the adsorption chamber, and the rear end of the adsorption chamber is provided with a smoke exhaust port; The collection chamber is composed of a collection beam grid evenly distributed inside, a liquid collecting tank and a liquid drain pipe arranged at the bottom; The capture beam grid is obtained by longitudinally winding a wire, the diameter of the wire is larger than the diameter of the maximum intercepted droplets and solid particles; the distance between the wires is larger than 3 times the diameter of the maximum intercepted droplets and solid particles; the wire material is metal wire, cotton wire, chemical fiber wire or mineral wool wire; the capture beam grid is tilted and has a certain angle with the horizontal plane, and the angle is 30-150°; the capture beam grid is a modular structure, the number of modules is several, and the distance between the modules of the capture beam grid is larger than 3 times the diameter of the maximum intercepted droplets and solid particles; The adsorption chamber is filled with active adsorption materials, including activated carbon or pumice.

2. The treatment equipment for polymorphic organic pollutant flue gas according to claim 1 is characterized in that: The angle between the capture beam grid and the horizontal plane is 90°.

3. A method for treating flue gas containing polymorphic organic pollutants, characterized in that: The device for treating flue gas containing polymorphic organic pollutants according to claim 1 specifically comprises the following steps: Step 1: The smoke is introduced into the uniform distribution chamber through the smoke duct, the smoke is evenly diffused in the uniform distribution chamber, and then enters the capture chamber after being pressure-equalized through the pressure-equalizing orifice plate; Step 2: The flue gas passes through the capture beam grid in the capture chamber to capture liquid and solid. The liquid and solid substances captured by the capture beam grid flow downward, enter the liquid collecting tank, and are discharged through the drain pipe; Step 3: The gaseous organic matter in the flue gas that is not captured in the capture chamber enters the adsorption chamber through the connecting chamber. The active adsorption material in the adsorption chamber adsorbs the gaseous organic matter in the flue gas, and finally the clean air after adsorption is discharged through the exhaust port; Step 4: When the collection beam grid is clogged due to adhesion and scaling, high-temperature gas or steam is introduced to heat the adhesion and scaling to flow to the liquid collecting tank and be discharged from the drain pipe; or the cover of the collection chamber is opened, the collection beam grid is taken out, and offline cleaning is performed.

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