A method for recycling fluorine-containing organic waste gas

Abstract

The invention discloses a resource recycling method for fluorine-containing organic waste gas, comprising the following steps: dust removal treatment of fluorine-containing organic waste gas, passing it into a tail gas incinerator for incineration to obtain incineration flue gas; passing the incineration flue gas into a heat transfer oil heat exchanger for preliminary cooling, and recovering its heat; passing the initially cooled incineration flue gas into a cooling washing tower for further cooling, and absorbing the fluorine element in the incineration flue gas to obtain a sodium fluoride solution; filtering the sodium fluoride solution and then passing it into a crystallization kettle for crystallization treatment, the heat source for the crystallization treatment comes from the heat transfer oil heat exchanger; centrifuging the crystallized product, collecting the solid phase, and drying to obtain sodium fluoride. The invention can not only effectively treat fluorine-containing waste gas and reduce environmental pollution, but also make full use of the heat of organic matter combustion to evaporate and prepare industrial-grade sodium fluoride, realize the maximum resource utilization of organic matter and fluorine in waste gas, realize zero emission in the true sense, and the equipment has good working conditions and can operate stably for a long time.

Description

Technical Field

[0001] The invention belongs to the field of waste gas treatment, and in particular relates to a method for treating fluorine-containing organic waste gas. Background Art

[0002] In industries such as organosilicon, oil refineries, petrochemicals, solar panel recycling, and waste lithium battery recycling, a large amount of fluorine-containing organic waste gas is often generated. The current main process is to first incinerate the organic waste gas, then absorb the fluoride in it with alkaline solution, and then the tail gas is discharged in compliance with the standards, and the fluorine-containing waste water is sent to sewage treatment. This process does not make resource utilization of fluorine in the waste gas, nor does it recycle heat. While consuming energy, it also produces a large amount of waste water, which is very uneconomical.

[0003] In response to the above problems, there are now some technologies for resource utilization of fluorine-containing organic waste gas. For example, in the lithium battery recycling and solar panel recycling industries, some technologies incinerate the fluorine-containing organic waste gas generated by battery cracking, and the high-temperature flue gas after incineration returns to the cracking furnace as a heating source. The fluorine-containing flue gas after releasing heat is then discharged after alkali washing. This technology can recycle the heat in the incineration waste gas, but there is a problem that the cracking furnace is easily corroded by fluoride, and fluorine is not utilized as a resource, and there is still a large amount of fluorine-containing wastewater or waste residue generated. There are also technologies that first incinerate the fluorine-containing organic waste gas, then use a quenching tower to cool the flue gas by spraying water on it, use alkaline washing to absorb the fluoride in it and then discharge the flue gas, add calcium hydroxide to the fluorine-containing waste water after alkaline washing, and remove the generated calcium fluoride by precipitation, filtration and other means. The salt-containing clear liquid is recycled and sprayed into the quenching tower to cool the flue gas. This technology uses salt-containing clear liquid as the spray water of the quenching tower. The salt-containing clear liquid has the risk of clogging the nozzle, and a large amount of calcium fluoride solid waste will still be generated, and the fluorine element is not reasonably utilized.

[0004] As can be seen from the above, the existing technology has completed the treatment of pollutants such as fluorine and dust in fluorine-containing organic waste gas, but it has produced a large amount of wastewater or waste residue, and more costs have to be invested in the treatment of the wastewater and waste residue. At the same time, there is also the problem that the heat and fluorine element in the high-temperature waste gas are not reasonably utilized. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings and defects mentioned in the above background technology and provide a method for resource recovery and utilization of fluorine-containing organic waste gas, which can fully recover and utilize the heat source generated by the combustion of the waste gas and convert the fluorine element into sodium fluoride, so that the fluorine element can be reasonably utilized.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is: A method for recycling fluorine-containing organic waste gas, comprising the following steps: S1: dust removal treatment is performed on the fluorine-containing organic waste gas, and then the waste gas is introduced into the tail gas incinerator for incineration treatment to obtain incineration flue gas; S2: passing the incineration flue gas into a heat transfer oil heat exchanger to preliminarily cool the incineration flue gas and recover the heat in the incineration flue gas; S3: passing the preliminarily cooled incineration flue gas into a cooling scrubber, further cooling the incineration flue gas by using the sodium hydroxide solution sprayed from the cooling scrubber, and absorbing the fluorine element in the incineration flue gas to obtain a sodium fluoride solution; S4: passing the sodium fluoride solution through a precision filter for filtration and then passing it through a crystallization kettle for crystallization, wherein the heat source during the crystallization process comes from the heat transfer oil heat exchanger in step S2; S5: centrifuging the crystallized product in the crystallization kettle, collecting the solid phase, and drying to obtain sodium fluoride.

[0007] In the above-mentioned resource recycling method of fluorine-containing organic waste gas, preferably, the distilled water generated during the crystallization process is passed into the cooling washing tower. Passing the distilled water into the cooling washing tower realizes the recycling of water resources and reduces the consumption of recycled water resources.

[0008] In the above-mentioned method for recycling and utilizing fluorine-containing organic waste gas, preferably, a mother liquid tank is provided between the precision filter and the crystallization kettle, the solution filtered by the precision filter is passed into the mother liquid tank for temporary storage, and the centrifugal mother liquid obtained by centrifugal treatment in step S5 enters the mother liquid tank. By providing a mother liquid tank, the solution filtered by the precision filter and the centrifugal mother liquid obtained by centrifugal treatment in step S5 can be temporarily stored and then processed in a unified and centralized manner.

[0009] The sodium fluoride solution in the mother liquid tank is pumped to the crystallization kettle for evaporation and crystallization. The evaporation rate of water is about 80%. After evaporation, the slurry is separated into solid and liquid by a centrifuge. The solid, i.e. sodium fluoride, is dried and packaged for sale. The liquid returns to the mother liquid tank and is evaporated with the newly generated sodium fluoride solution. Evaporation can be carried out by reduced pressure evaporation. The heat source is high-temperature heat transfer oil that absorbs the high-temperature flue gas temperature after incineration. The distilled water produced by evaporation can be used for cooling the washing tower spray.

[0010] In the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas, preferably, the temperature of the incineration flue gas is 900-1100°C, the temperature of the incineration flue gas is reduced to 480-550°C after the incineration flue gas is initially cooled by the heat transfer oil heat exchanger, and the temperature of the incineration flue gas is further cooled by the cooling scrubber to below 50°C. The incineration temperature is 900-1100°C, which can remove more than 99% of organic matter in the flue gas; the high-temperature flue gas is initially cooled by heat transfer oil through the heat exchanger, and the flue gas temperature is reduced to 480-550°C. At the same time, the heat absorbed by the heat transfer oil can provide heat energy for the crystallization of the rear-end crystallization kettle; the flue gas is further cooled by the cooling scrubber to reduce the temperature to below 50°C, so that the flue gas temperature drops rapidly, skipping the temperature zone where dioxins are generated, and reducing the generation of dioxins.

[0011] In the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas, preferably, the dust removal method of dust removal treatment includes gravity dust removal and cyclone dust removal. Gravity dust removal and cyclone dust removal can remove most of the dust in the fluorine-containing organic waste gas, avoid excessive dust deposition in the heat transfer oil heat exchanger, and reduce the processing load of the subsequent cooling washing tower.

[0012] In the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas, preferably, the cooling washing tower is a power wave washing tower, and the power wave washing tower comprises a vertically arranged cylinder, the top of the cylinder is provided with an air inlet, and the cylinder is provided with a first nozzle for spraying out the absorption liquid and contacting the intake air of the air inlet to form a first foam absorption zone, a gas discharge device for gas discharge, and a suction filter device for filtering the absorption liquid, and the first nozzle is provided with a device for promoting the absorption liquid in the first foam absorption zone to flow downward along the cylinder wall of the cylinder and the gas to flow along the middle of the cylinder. The first flow guide device for uniform downward flow in the cavity; the above-mentioned power wave washing tower changes the traditional power wave reverse nozzle and liquid storage section into an integrated cylinder, and a first flow guide device and a first nozzle are arranged in the cylinder to cool the exhaust gas, remove dust and remove fluorine and phosphorus, and a gas discharge device and a filtration device are arranged, which can realize the functions of gas discharge and repeated filtration of the absorption liquid, can realize multiple functions in one power wave washing tower, can replace multiple equipment in the existing process flow, and has good waste gas treatment effect, can realize high-efficiency treatment of fluorine-containing organic waste gas, and has good application prospects.

[0013] In the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas, preferably, a second nozzle for spraying out absorption liquid and contacting the gas passing through the first foam absorption zone to form a second foam absorption zone is further provided in the cylinder between the first nozzle and the gas discharge device, and a second flow guide device is provided at the second nozzle for promoting the absorption liquid in the second foam absorption zone to flow downward along the cylinder wall of the cylinder and the gas to flow uniformly downward along the middle cavity of the cylinder. By adding a second nozzle and a second flow guide device between the first nozzle and the gas discharge device, the contact efficiency between the gas and the absorption liquid can be further improved, a more effective second foam absorption zone can be formed, and the gas cooling, dust reduction, and fluorine and phosphorus removal effects can be improved. The first flow guide device and the second flow guide device used in the present invention optimize the gas-liquid flow path, so that the absorption liquid flows uniformly along the cylinder wall, and the gas flows smoothly downward in the middle cavity. With the two-stage nozzle, the washing effect is enhanced, the energy consumption is reduced, and the gas-liquid separation performance is improved, and finally the working efficiency and stability of the entire power wave washing tower are improved.

[0014] In the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas, preferably, the first guide device and the second guide device each include a pair of upper and lower conical plates spaced apart from each other, the upper and lower conical plates have central openings, and are sleeved on the first nozzle or the second nozzle through the openings, and the outer edges of the upper and lower conical plates are provided with gaps between the outer edges of the upper and lower conical plates and the cylinder wall of the cylinder for the absorption liquid to flow downward, and the upper and lower conical plates are provided with through holes for gas to pass through; the setting of the conical plates can guide the absorption liquid to flow downward along the cylinder wall, while the gas flows downward evenly in the middle cavity of the cylinder, thereby reducing mutual interference between gas and liquid and improving the orderliness of the flow.

[0015] In the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas, preferably, the upper conical plate is evenly provided with a plurality of upper fan-shaped gas passage holes, so that the upper conical plate forms a structure in which the upper fan-shaped gas passage holes and the upper fan-shaped liquid guide plate are alternately arranged, and the lower conical plate is evenly provided with a plurality of lower fan-shaped gas passage holes, so that the lower conical plate forms a structure in which the lower fan-shaped gas passage holes and the lower fan-shaped liquid guide plate are alternately arranged, and the upper fan-shaped gas passage holes and the lower fan-shaped gas passage holes are staggered, so that the upper conical plate and the lower conical plate are superimposed to form a non-porous cone; when the liquid flows to the upper fan-shaped liquid guide plate, the liquid will flow along the upper fan-shaped liquid guide plate. The liquid guide plate flows to the edge of the upper conical plate and flows downward along the cylinder wall, and the gas flows downward through the upper fan-shaped gas through hole. If there is liquid flowing downward through the upper fan-shaped gas through hole, due to the staggered arrangement of the upper fan-shaped gas through hole and the lower fan-shaped gas through hole, the liquid will also fall to the lower fan-shaped liquid guide plate, and through the guiding effect of the lower fan-shaped liquid guide plate, flow to the edge of the lower conical plate and flow downward along the cylinder wall, while the gas continues to flow downward along the lower fan-shaped gas through hole. This structural design helps the liquid flow along the cylinder wall, while the gas flows downward evenly in the middle cavity of the cylinder, reducing mutual interference, enhancing flow efficiency, and improving the cooling effect. In addition, the gas can be better diverted through the upper fan-shaped gas through hole and the lower fan-shaped gas through hole to improve the treatment effect.

[0016] In the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas, preferably, both sides of the upper fan-shaped liquid guide plate and both sides of the lower fan-shaped liquid guide plate are provided with baffles for guiding the absorption liquid falling on them to the edge. The baffle can effectively guide the absorption liquid to the edge, ensuring that the liquid is guided to the edge after falling on the upper fan-shaped liquid guide plate and the lower fan-shaped liquid guide plate so that the liquid flows downward along the cylinder wall. The baffle can be set on the edges of both sides of the upper fan-shaped liquid guide plate and the lower fan-shaped liquid guide plate, and cooperate with the inclination angle of the upper fan-shaped liquid guide plate and the lower fan-shaped liquid guide plate themselves, so as to easily guide the absorption liquid.

[0017] In the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas, preferably, a third flow guide device is provided in the cylinder above the first nozzle to promote the absorption liquid in the first foam absorption zone to flow downward along the cylinder wall of the cylinder and the gas to flow uniformly downward along the middle cavity of the cylinder, and the third flow guide device is located above the first foam absorption zone and connected to the first foam absorption zone. The structural form of the third flow guide device can be the same as that of the first flow guide device and the second flow guide device, that is, the third flow guide device includes a pair of upper and lower conical plates spaced apart from each other (the center of the upper and lower conical plates may not have a hole), and the outer edges of the upper and lower conical plates are provided with gaps for the absorption liquid to flow downward between the outer edges and the cylinder wall of the cylinder, and the upper and lower conical plates are provided with through holes for gas to pass through. The upper conical plate is evenly provided with a plurality of upper fan-shaped gas passage holes, so that the upper conical plate forms a structure in which the upper fan-shaped gas passage holes and the upper fan-shaped liquid guide plates are alternately arranged; the lower conical plate is evenly provided with a plurality of lower fan-shaped gas passage holes, so that the lower conical plate forms a structure in which the lower fan-shaped gas passage holes and the lower fan-shaped liquid guide plates are alternately arranged, and the upper fan-shaped gas passage holes and the lower fan-shaped gas passage holes are staggered, so that the upper conical plate and the lower conical plate form a non-porous cone after being superimposed.

[0018] The third flow guide device is located above the first foam absorption zone and connected to the first foam absorption zone. The liquid sprayed from the first nozzle will reach the third flow guide device. At this time, a liquid film will be formed at the third flow guide device. The third flow guide device helps to promote the absorption liquid in the first foam absorption zone to flow downward along the cylinder wall and divert the gas entering from the air inlet. This design can more effectively manage and control the liquid flow path and realize the gas diversion, thereby improving the treatment effect of the first foam absorption zone.

[0019] In the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas, preferably, the gas exhaust device includes a gas exhaust pipe and a diverter hood, the inlet of one end of the gas exhaust pipe is located in the middle of the inner cavity of the cylinder, and the outlet of the other end of the gas exhaust pipe is located outside the cylinder, and the diverter hood is arranged above the inlet of the gas exhaust pipe, and the inner wall of the diverter hood and the outer wall of the gas exhaust pipe are provided with a plurality of upwardly inclined and spaced defogger plates (the defogger plates on the inner wall of the diverter hood and the defogger plates on the outer wall of the gas exhaust pipe are arranged alternately and spaced); by arranging the diverter hood above the inlet of the gas exhaust pipe, the diverter hood can prevent the liquid from falling directly into the gas exhaust pipe, and installing a plurality of upwardly inclined defogger plates on the inner wall of the diverter hood and the outer wall of the exhaust pipe can effectively separate the gas and the liquid mixed in the gas, and reduce the liquid droplets carried in the gas. The above-mentioned defogger plate can adopt the device in the prior art.

[0020] In the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas, preferably, the suction filtration device includes a columnar filter body, the upper and lower ends of the columnar filter body are respectively closed by an upper sealing plate and a lower sealing plate, the lower sealing plate is connected to a negative pressure suction pipe, and the upper sealing plate is connected to a backwashing pipe. The suction filtration device can directly separate the smoke captured in the absorption liquid, and the separated absorption liquid is used for spraying to ensure the dust removal effect and the nozzle is always in good working condition. The design of the columnar filter body can provide a larger surface area, so that it can more fully contact the pollutants in the absorption liquid, thereby improving the filtration efficiency; the negative pressure suction pipe connected to the lower sealing plate uses the negative pressure suction principle to achieve the effect of suction filtration; the backwashing pipe connected to the upper sealing plate can be backwashed. When the filtering performance of the columnar filter body deteriorates due to blockage, backwashing can be performed to maintain the cleanliness and filtering efficiency of the columnar filter body. The above-mentioned backwashing solution can come from the clear liquid in the negative pressure suction pipe.

[0021] In the above-mentioned method for resource recovery and utilization of fluorine-containing organic waste gas, preferably, the outer wall of the cylinder is provided with a honeycomb cooling jacket, the lower end of the honeycomb cooling jacket is provided with a cooling water supply port, and the upper end of the honeycomb cooling jacket is provided with a cooling water return port. The setting of the honeycomb cooling jacket is equivalent to using circulating cooling water to cool the liquid film flowing down the inner wall of the cylinder in the form of falling film countercurrent cooling, further enhancing the cooling capacity of the circulating spray water on the waste gas, and at the same time, the equipment structure is simpler and has better strength. The lower end of the honeycomb cooling jacket is provided with a cooling water supply port, and the upper end is provided with a cooling water return port. This design allows the cooling water to be evenly distributed in the jacket, thereby improving the cooling efficiency. At the same time, it helps to collect and recycle cooling water and reduce the waste of water resources.

[0022] In the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas, preferably, the outlet of the suction filtration device is connected to a clear liquid main pipe, and the outlet of the clear liquid main pipe includes a first branch and a second branch, and the first branch and the second branch are respectively connected to the first nozzle and the second nozzle. Through the coordinated work of the two nozzles, the absorption area can be more effectively covered, and the cooling efficiency and effect are improved. The absorption liquid sprayed from the first branch and the second branch can be the clear liquid obtained by suction filtration of the suction filtration device, and the absorption liquid can be recycled.

[0023] In the above-mentioned method for recycling and utilizing fluorine-containing organic waste gas, preferably, an online pH monitor is provided in the cylinder, and an alkali solution adding and distributing device (sodium hydroxide solution) is also provided on the cylinder. The online pH monitor can monitor the pH value in the cylinder in real time, and alkali solution can be added into the cylinder through the alkali solution adding and distributing device to absorb fluorine-containing gas. The above-mentioned alkali solution adding and distributing device can adopt a ring made of a pipe, with holes opened on the ring for liquid distribution, and the alkali solution pipeline is connected to the ring.

[0024] The power wave washing tower used in the above-mentioned resource recovery and utilization method of fluorine-containing organic waste gas changes the traditional power wave reverse nozzle and liquid storage section into an integrated cylinder, and sets a guide device (first, second, and third guide devices) in the cylinder to cooperate with the nozzle (first nozzle and second nozzle) to make the spray reflux liquid form a liquid film on the inner wall of the cylinder evenly and flow downward to protect the equipment from over-temperature. Multi-stage liquid spray is designed to cool the flue gas in steps. The specially designed guide device has the function of breaking up and guiding the spray water of the next-stage nozzle (that is, the third guide device can cooperate with the first nozzle, and the first guide device can cooperate with the second nozzle), further enhancing the formation efficiency and distribution uniformity of the foam in the foam zone, thereby greatly improving the contact area and contact time between the flue gas and the spray water, so as to achieve a rapid reduction in the flue gas temperature to 50°C, and can achieve cooling, dust removal and fluorine removal of the waste gas. At the same time, the gas discharge device and the suction filtration device are provided to realize the functions of gas discharge and repeated filtration of the absorption liquid, which can greatly improve the dust removal effect, and also solve the problems of large footprint, high cost and high labor intensity of the external filter press. The power wave washing tower of the present invention can realize multiple functions, can replace multiple equipment in the existing process flow, and has a good treatment effect on waste gas. The present invention uses a power wave washing tower to achieve multiple functions of rapid cooling, dust removal, and fluorine removal. The gas discharged from the power wave washing tower only needs to be treated by an activated carbon box, which can complete the rapid cooling of high-temperature tail gas, and can avoid the temperature range where dioxins are easily generated, reduce the generation of dioxins in the cooling process, shorten the process flow, reduce the number of equipment, and reduce investment costs and operating costs.

[0025] Compared with the prior art, the advantages of the present invention are: The resource recovery and utilization method of fluorine-containing organic waste gas of the present invention can not only effectively treat fluorine-containing waste gas and reduce environmental pollution, but also fully utilize the heat of organic matter combustion to evaporate and prepare industrial-grade sodium fluoride, thereby realizing the maximum resource utilization of organic matter and fluorine in the waste gas, and realizing the transformation of waste into treasure and zero emission in a true sense with high efficiency and low consumption, without the need to treat a large amount of fluorine-containing waste water and waste residue, lower energy consumption and better economic benefits.

[0026] The resource recovery and utilization method of fluorine-containing organic waste gas of the present invention removes impurities from fluorine-containing organic waste gas and solution layer by layer through high-temperature dust removal, cooling washing tower dust removal and precision filtration dust removal, so that solid impurities in the sodium fluoride solution finally entering the crystallization kettle are fully removed, ensuring that the sodium fluoride product evaporated and crystallized fully meets the industrial grade index. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 This is a process flow chart of the resource recovery and utilization method of fluorine-containing organic waste gas in this embodiment.

[0029] Figure 2 Schematic diagram of the structure of the dynamic wave washing tower in the embodiment.

[0030] Figure 3 It is a schematic diagram of the structure of the first nozzle and the first flow guide device in the embodiment.

[0031] Figure 4 for Figure 3 Schematic diagram of the structure of the AA section.

[0032] Figure 5 for Figure 3 Schematic diagram of the structure of the BB section.

[0033] Figure 6 Schematic diagram of the structure of the gas exhaust device in the embodiment.

[0034] Figure 7 for Figure 6 Schematic diagram of the structure of the CC section.

[0035] Figure 8 Schematic diagram of the structure of the filtration device in the embodiment.

[0036] Fig. 9 It is a structural schematic diagram of the alkali solution uniform distribution device in the embodiment.

[0037] Fig.10 for Fig. 9 Schematic diagram of the structure of the DD section.

[0038] Legend 1. Cylinder; 2. Air inlet; 3. First nozzle; 4. Gas discharge device; 5. Filter device; 6. First flow guide device; 7. Second nozzle; 8. Second flow guide device; 9. Upper conical plate; 91. Upper fan-shaped gas through hole; 92. Upper fan-shaped liquid flow guide plate; 10. Lower conical plate; 101. Lower fan-shaped gas through hole; 102. Lower fan-shaped liquid flow guide plate; 11. Baffle; 12. Gap; 14. Third flow guide Flow device; 15. Gas discharge pipe; 16. Diverter hood; 17. Demisting plate; 18. Columnar filter body; 19. Upper sealing plate; 20. Lower sealing plate; 21. Negative pressure suction pipeline; 22. Backwash pipeline; 23. Honeycomb cooling jacket; 24. Cooling water supply port; 25. Cooling water return port; 26. pH value online monitor; 27. Alkali solution dosing and distribution device; 28. Inspection port; 29. ​​Slurry outlet; 30. Activated carbon box. DETAILED DESCRIPTION

[0039] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0040] It should be noted that when an element is described as being "fixed, fixed, connected or connected to" another element, it can be directly fixed, fixed, connected or connected to the other element, or it can be indirectly fixed, fixed, connected or connected to the other element through other intermediate connectors.

[0041] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0042] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0043] Example: like Figure 1 As shown, the resource recovery and utilization method of fluorine-containing organic waste gas in this embodiment includes the following steps: S1: dust removal treatment is performed on the fluorine-containing organic waste gas, and then the waste gas is introduced into the tail gas incinerator, and incinerated in the presence of natural gas and combustion-supporting air to obtain incineration flue gas; S2: passing the incineration flue gas into the thermal oil heat exchanger to initially cool the incineration flue gas and recover the heat in the incineration flue gas; S3: passing the preliminarily cooled incineration flue gas into a cooling scrubber, further cooling the incineration flue gas by using the sodium hydroxide solution sprayed from the cooling scrubber, and absorbing the fluorine element in the incineration flue gas to obtain a sodium fluoride solution; S4: passing the sodium fluoride solution through a precision filter for filtration and then passing it through a crystallization kettle for crystallization, wherein the heat source during the crystallization process comes from the heat transfer oil heat exchanger in step S2; S5: centrifuging the crystallized product in the crystallization kettle, collecting the solid phase, and drying to obtain sodium fluoride.

[0044] To meet the above requirements, the tail gas incinerator can adopt steel lining high temperature casting materials and other forms; the heat exchanger can adopt high temperature resistant metal materials such as 310SS; the filter and mother liquid tank are made of non-metallic materials that can withstand fluorine corrosion; the crystallization kettle liner and centrifuge drum are made of 316SS, 20 alloy, monel alloy and other metal materials resistant to sodium fluoride corrosion.

[0045] In this embodiment, the distilled water produced during the crystallization process is passed into the cooling washing tower.

[0046] In this embodiment, a mother liquid tank is provided between the precision filter and the crystallization kettle, the solution filtered by the precision filter is passed into the mother liquid tank for temporary storage, and the centrifuged mother liquid obtained by the centrifugal treatment in step S5 enters the mother liquid tank.

[0047] In this embodiment, the temperature of the incineration flue gas is 900-1100°C. After the incineration flue gas passes through the heat transfer oil heat exchanger for initial cooling, the temperature drops to 500°C. After the incineration flue gas passes through the cooling washing tower for further cooling, the temperature drops to below 50°C.

[0048] In this embodiment, the dust removal methods of the dust removal process include gravity dust removal and cyclone dust removal.

[0049] like Figure 2 As shown, in this embodiment, the cooling washing tower is a dynamic wave washing tower, which includes a vertically arranged cylinder 1, an air inlet 2 is provided on the top of the cylinder 1, and a first nozzle 3 for spraying absorption liquid and contacting the air intake of the air inlet 2 to form a first foam absorption zone, a gas discharge device 4 for gas discharge and a filtration device 5 for filtering the absorption liquid are arranged in sequence in the cylinder 1 from top to bottom. The first nozzle 3 is provided with a first guide device 6 for promoting the absorption liquid in the first foam absorption zone to flow downward along the cylinder wall of the cylinder 1 and the gas to flow uniformly downward along the middle cavity of the cylinder 1.

[0050] In this embodiment, a second nozzle 7 for spraying out the absorption liquid and contacting the gas passing through the first foam absorption zone to form a second foam absorption zone is further provided between the first nozzle 3 and the gas discharge device 4 in the cylinder 1. A second flow guide device 8 for promoting the absorption liquid in the second foam absorption zone to flow downward along the cylinder wall of the cylinder 1 and the gas to flow uniformly downward along the middle cavity of the cylinder 1 is provided at the second nozzle 7. In this embodiment, the first nozzle 3 and the second nozzle 7 are used for two-stage spray cooling, and two sets of flow guide devices are also provided accordingly. Three or four nozzles can be provided for other cooling processes according to needs, and cooling treatment can be performed with a corresponding number of flow guide devices.

[0051] like Figure 3-Figure 5 As shown, in this embodiment, the first guide device 6 and the second guide device 8 each include a pair of upper conical plates 9 and lower conical plates 10 spaced apart from each other, the upper conical plates 9 and the lower conical plates 10 have central openings, and are sleeved on the first nozzle 3 or the second nozzle 7 through the openings, and gaps 12 for the downward flow of the absorption liquid are provided between the outer edges of the upper conical plates 9 and the lower conical plates 10 and the cylinder wall of the cylinder 1, and through holes for the gas to pass through are provided on the upper conical plates 9 and the lower conical plates 10.

[0052] In this embodiment, a plurality of upper fan-shaped gas passage holes 91 are evenly provided on the upper conical plate 9, so that the upper conical plate 9 forms a structure in which the upper fan-shaped gas passage holes 91 and the upper fan-shaped liquid guide plates 92 are alternately arranged, and a plurality of lower fan-shaped gas passage holes 101 are evenly provided on the lower conical plate 10, so that the lower conical plate 10 forms a structure in which the lower fan-shaped gas passage holes 101 and the lower fan-shaped liquid guide plates 102 are alternately arranged, and the upper fan-shaped gas passage holes 91 and the lower fan-shaped gas passage holes 101 are staggered, so that the upper conical plate 9 and the lower conical plate 10 are superimposed to form a non-porous cone.

[0053] In this embodiment, baffles 11 are provided on both sides of the upper fan-shaped liquid guide plate 92 and both sides of the lower fan-shaped liquid guide plate 102 for guiding the absorption liquid falling thereon to the edge.

[0054] In this embodiment, a third flow guide device 14 is provided above the first nozzle 3 in the cylinder 1 to promote the absorption liquid in the first foam absorption zone to flow downward along the cylinder wall of the cylinder 1 and the gas to flow evenly downward along the middle cavity of the cylinder 1. The third flow guide device 14 is located above the first foam absorption zone and connected to the first foam absorption zone. The structure of the third flow guide device 14 can be similar to that of the first flow guide device 6 and the second flow guide device 8, and the structure of the first flow guide device 6 and the second flow guide device 8 can be referred to.

[0055] like Figure 6 , Figure 7As shown, in this embodiment, the gas exhaust device 4 includes a gas exhaust pipe 15 and a diverter hood 16. The inlet at one end of the gas exhaust pipe 15 is located in the middle of the inner cavity of the cylinder 1, and the outlet at the other end of the gas exhaust pipe 15 is located outside the cylinder 1. The diverter hood 16 is arranged above the inlet of the gas exhaust pipe 15, and a plurality of upwardly inclined and spaced defogger plates 17 are provided on the inner wall of the diverter hood 16 and the outer wall of the gas exhaust pipe 15.

[0056] like Figure 8 As shown, in this embodiment, the suction filter device 5 includes a columnar filter body 18, the upper and lower ends of the columnar filter body 18 are respectively closed by an upper sealing plate 19 and a lower sealing plate 20, a negative pressure suction pipe 21 is connected to the lower sealing plate 20, and a backwash pipe 22 is connected to the upper sealing plate 19. The absorption liquid after the spray gas is filtered and processed by the suction filter device 5, and the obtained absorption liquid enters the clear liquid main pipe 34 through the negative pressure suction pipe 21. When the suction filter device 5 is cleaned, it only needs to add clear liquid to the backwash pipe 22 to complete it.

[0057] like Figure 2 As shown, in this embodiment, the outer wall of the cylinder 1 is provided with a honeycomb cooling jacket 23, the lower end of the honeycomb cooling jacket 23 is provided with a cooling water supply port 24, and the upper end of the honeycomb cooling jacket 23 is provided with a cooling water return port 25.

[0058] like Figure 2 , Fig. 9 , Fig.10 As shown, in this embodiment, a pH value online monitor 26 is provided in the cylinder 1, and an alkali solution adding and distributing device 27 is also provided on the cylinder 1. The pH value online monitor 26 can monitor the pH value of the liquid online, and the alkali solution adding and distributing device 27 can replenish alkali solution into the cylinder 1 in time according to the monitored pH value to absorb the fluorine-containing gas in the cylinder 1. The alkali solution adding and distributing device 27 can be a ring structure.

[0059] like Figure 2 As shown, in this embodiment, a plurality of inspection ports 28 are provided on the cylinder 1, and the plurality of inspection ports 28 are located near the first nozzle 3 and the first flow guide device 6, the second nozzle 7 and the second flow guide device 8, the gas exhaust device 4, and the filtration device 5, so as to facilitate the inspection and maintenance of each device and ensure the long-term and stable operation of the equipment.

[0060] like Figure 2 As shown, in this embodiment, a slurry outlet 29 is provided below the cylinder 1, and the slurry deposited in the cylinder 1 can be discharged outward through the slurry outlet 29, which is easy to operate.

[0061] like Figure 2 As shown, in this embodiment, the power wave scrubber is also connected to an activated carbon box 30 for removing odors from the flue gas, and the flue gas is discharged after being deodorized.

[0062] The fluorine-containing organic waste gas resource recovery and utilization method in the above embodiment is used to treat the fluorine-containing organic waste gas generated by the pyrolysis of a waste lithium battery. The waste gas volume is about 3000Nm³ / h, the waste gas temperature is 300°C, the organic matter content is about 304kg / h, the fluorine content (in terms of fluoride ions) is about 42.6kg / h, and the dust content is about 2000mg / Nm 3 .

[0063] After treatment, the exhaust gas index fully meets the "Technical Specifications for Pollution Control of Waste Lithium-ion Power Battery Treatment (Trial)" (HJ1186-2021) and relevant standards. The output of by-product sodium fluoride is about 907t / a, and the product index fully meets the first-class standard specified in the non-ferrous metal industry standard YS / T 517-2006 "Sodium Fluoride" of the People's Republic of China.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for recycling fluorine-containing organic waste gas, characterized in that: The following steps are involved: S1: dust removal treatment is performed on the fluorine-containing organic waste gas, and then the waste gas is introduced into the tail gas incinerator for incineration treatment to obtain incineration flue gas; S2: passing the incineration flue gas into a heat transfer oil heat exchanger to preliminarily cool the incineration flue gas and recover the heat in the incineration flue gas; S3: passing the preliminarily cooled incineration flue gas into a cooling scrubber, further cooling the incineration flue gas by using the sodium hydroxide solution sprayed from the cooling scrubber, and absorbing the fluorine element in the incineration flue gas to obtain a sodium fluoride solution; S4: passing the sodium fluoride solution through a precision filter for filtration and then passing it through a crystallization kettle for crystallization, wherein the heat source during the crystallization process comes from the heat transfer oil heat exchanger in step S2; S5: centrifuging the crystallized product in the crystallization kettle, collecting the solid phase, and drying to obtain sodium fluoride.

2. The method for recycling fluorine-containing organic waste gas according to claim 1, characterized in that: The distilled water produced during the crystallization process is introduced into the cooling washing tower.

3. The method for recycling fluorine-containing organic waste gas according to claim 1, characterized in that: A mother liquid tank is provided between the precision filter and the crystallization kettle. The solution filtered by the precision filter is passed into the mother liquid tank for temporary storage, and the centrifuged mother liquid obtained by the centrifugal treatment in step S5 enters the mother liquid tank.

4. The method for recycling fluorine-containing organic waste gas according to claim 1, characterized in that: The temperature of the incineration flue gas is 900-1100°C. After the incineration flue gas is initially cooled by passing through a heat transfer oil heat exchanger, the temperature drops to 480-550°C. After the incineration flue gas is further cooled by passing through a cooling washing tower, the temperature drops to below 50°C.

5. The method for recycling fluorine-containing organic waste gas according to claim 1, characterized in that: The dust removal methods of dust removal treatment include gravity dust removal and cyclone dust removal.

6. The method for recycling fluorine-containing organic waste gas according to any one of claims 1 to 5, characterized in that: The cooling washing tower is a power wave washing tower, comprising a vertically arranged cylinder (1), the top of the cylinder (1) being provided with an air inlet (2), the cylinder (1) being provided with a first nozzle (3) for spraying out absorption liquid to contact the air from the air inlet (2) and forming a first foam absorption zone, a gas discharge device (4) for gas discharge, and a suction filter device (5) for absorption liquid filtration, the first nozzle (3) being provided with a first flow guide device (6) for promoting the absorption liquid in the first foam absorption zone to flow downward along the cylinder wall of the cylinder (1) and the gas to flow evenly downward along the middle cavity of the cylinder (1); A second nozzle (7) for spraying out absorption liquid to contact the gas passing through the first foam absorption zone and forming a second foam absorption zone is provided in the cylinder (1) between the first nozzle (3) and the gas exhaust device (4). The second nozzle (7) is provided with a second flow guide device (8) for promoting the absorption liquid in the second foam absorption zone to flow downward along the cylinder wall of the cylinder (1) and the gas to flow evenly downward along the central cavity of the cylinder (1).

7. The method for recycling fluorine-containing organic waste gas according to claim 6, characterized in that: The first flow guide device (6) and the second flow guide device (8) each comprise a pair of upper conical plates (9) and lower conical plates (10) spaced apart from each other, the upper conical plates (9) and lower conical plates (10) each having a central opening and being sleeved on the first nozzle (3) or the second nozzle (7) through the opening, a gap (12) for downward flow of absorption liquid being provided between the outer edges of the upper conical plates (9) and lower conical plates (10) and the cylinder wall of the cylinder (1), and through holes for gas to pass through being provided on the upper conical plates (9) and lower conical plates (10); The upper conical plate (9) is evenly provided with a plurality of upper fan-shaped gas passage holes (91), so that the upper conical plate (9) forms a structure in which the upper fan-shaped gas passage holes (91) and the upper fan-shaped liquid guide plates (92) are alternately arranged; the lower conical plate (10) is evenly provided with a plurality of lower fan-shaped gas passage holes (101), so that the lower conical plate (10) forms a structure in which the lower fan-shaped gas passage holes (101) and the lower fan-shaped liquid guide plates (102) are alternately arranged; and the upper fan-shaped gas passage holes (91) and the lower fan-shaped gas passage holes (101) are staggered, so that the upper conical plate (9) and the lower conical plate (10) form a non-porous cone when they are superimposed; Both sides of the upper fan-shaped liquid guide plate (92) and both sides of the lower fan-shaped liquid guide plate (102) are provided with baffles (11) for guiding the absorption liquid falling onto them to the edges.

8. The method for recycling fluorine-containing organic waste gas according to claim 6, characterized in that: A third flow guide device (14) is provided above the first nozzle (3) in the cylinder (1) for promoting the absorption liquid in the first foam absorption zone to flow downward along the cylinder wall of the cylinder (1) and the gas to flow evenly downward along the middle cavity of the cylinder (1). The third flow guide device (14) is located above the first foam absorption zone and is connected to the first foam absorption zone.

9. The method for recycling fluorine-containing organic waste gas according to claim 6, characterized in that: The gas discharge device (4) comprises a gas discharge pipe (15) and a flow divider (16); an inlet at one end of the gas discharge pipe (15) is located in the middle of the inner cavity of the cylinder (1); an outlet at the other end of the gas discharge pipe (15) is located outside the cylinder (1); the flow divider (16) is arranged above the inlet of the gas discharge pipe (15); and a plurality of upwardly inclined and spaced defogger plates (17) are provided on the inner wall of the flow divider (16) and the outer wall of the gas discharge pipe (15); The filtration device (5) comprises a columnar filter body (18), the upper and lower ends of the columnar filter body (18) being respectively sealed by an upper sealing plate (19) and a lower sealing plate (20), the lower sealing plate (20) being connected to a negative pressure suction pipe (21), and the upper sealing plate (19) being connected to a backwash pipe (22).

10. The method for recycling fluorine-containing organic waste gas according to claim 6, characterized in that: The outer wall of the cylinder (1) is provided with a honeycomb cooling jacket (23), the lower end of the honeycomb cooling jacket (23) is provided with a cooling water supply port (24), and the upper end of the honeycomb cooling jacket (23) is provided with a cooling water return port (25).

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