Deacidification recovery system of nitrogen for refrigerant R134a production

Abstract

The utility model provides a deacidification recovery system of nitrogen for refrigerant R134a production, which belongs to the technical field of fluorination and comprises a fluorination water scrubber, a nitrogen recovery alkaline scrubber, a nitrogen buffer tank, a nitrogen compressor, a refrigerated dryer and a nitrogen storage tank which are sequentially connected along the nitrogen flow direction. A first demister is arranged between the fluorination water washing tower and the nitrogen recovery alkaline washing tower, and a liquid phase outlet in the bottom of the first demister is connected with a liquid return port of the fluorination water washing tower; a second demister is arranged between the nitrogen recovery alkaline washing tower and the nitrogen buffer tank, and a liquid phase outlet in the bottom of the second demister is connected with a liquid return port of the nitrogen recovery alkaline washing tower; an outlet of the nitrogen compressor is further connected with a gas return port of the nitrogen buffer tank, and a nitrogen recovery cooler is further arranged between the nitrogen compressor and the gas return port of the nitrogen buffer tank. According to the system, the waste nitrogen is subjected to deacidification treatment and recycling, and the purposes of saving energy, reducing emission and reducing the production cost are achieved.

Description

Technical Field

[0001] This utility model relates to the field of fluorination technology, and in particular to an acid removal and recovery system for nitrogen gas used in the production of refrigerant R134a. Background Technology

[0002] 1,1,1,2-Tetrafluoroethane, also known as R134a, HFC-134a, or norflurane, is an organic compound with the chemical formula C2H2F4. Because R134a belongs to the HFC class (hydrofluorocarbons), it does not deplete the ozone layer and is currently recognized and recommended for use by the vast majority of countries worldwide. It is also the most widely used environmentally friendly refrigerant for medium and low temperatures, primarily used in refrigeration equipment such as refrigerators, automotive air conditioners, central air conditioners, dehumidifiers, cold storage facilities, and refrigeration condensing units. It is also used in aerosol propellants (such as bronchodilators), medical aerosols, insecticide propellants, polymer (plastic) physical foaming agents, and as a protective gas for magnesium alloys.

[0003] The production of refrigerant R134a primarily uses trichloroethylene (TCE) and anhydrous hydrogen fluoride (AHF) as raw materials. These two materials are mixed in a specific ratio and reacted in a fluorination reactor containing a catalyst to produce R134a, with HCl as a byproduct. However, high-purity nitrogen is required for catalyst activation and regeneration, molecular sieve dryer regeneration, and replacement of pipelines in R134a production facilities. Furthermore, the catalyst regeneration process is lengthy, necessitating a continuous nitrogen supply, resulting in significant high-purity nitrogen consumption. Currently, most companies directly release the waste nitrogen from replacement or regeneration into the atmosphere, leading to substantial energy and resource waste. Moreover, the waste nitrogen from catalyst activation and regeneration often contains large amounts of acidic gases, which, if released directly into the atmosphere without treatment, will cause environmental pollution. Utility Model Content

[0004] This invention provides an acid removal and recovery system for nitrogen used in the production of refrigerant R134a, which solves the pollution problem caused by waste nitrogen emissions and also addresses the source of high-purity nitrogen. By treating and recycling waste nitrogen, the system achieves energy conservation and emission reduction.

[0005] Specifically, this utility model provides an acid removal and recovery system for nitrogen used in the production of refrigerant R134a, comprising: a fluorinated water scrubbing tower, a nitrogen recovery alkaline scrubbing tower, a nitrogen buffer tank, a nitrogen compressor, a refrigerated dryer, and a nitrogen storage tank, connected sequentially along the nitrogen flow direction; a first demister is provided between the fluorinated water scrubbing tower and the nitrogen recovery alkaline scrubbing tower, and the liquid phase outlet at the bottom of the first demister is connected to the return liquid port of the fluorinated water scrubbing tower; a second demister is provided between the nitrogen recovery alkaline scrubbing tower and the nitrogen buffer tank, and the bottom of the second demister... The liquid outlet of the nitrogen recovery alkaline scrubbing tower is connected to the return liquid port of the nitrogen recovery alkaline scrubbing tower; the outlet of the nitrogen compressor is also connected to the return gas port of the nitrogen buffer tank, and a nitrogen recovery cooler is also installed between the nitrogen compressor and the return gas port of the nitrogen buffer tank; the bottom outlet of the fluorinated water scrubbing tower is connected to the top spray pipe of the fluorinated water scrubbing tower through a fluorinated water scrubbing circulation pump and a fluorinated water scrubbing cooler installed in sequence; the bottom outlet of the nitrogen recovery alkaline scrubbing tower is connected to the top spray pipe of the nitrogen recovery alkaline scrubbing tower through an alkaline scrubbing circulation pump and an alkaline scrubbing cooler installed in sequence.

[0006] Furthermore, the bottoms of the fluorinated water washing tower and the nitrogen recovery alkaline washing tower are respectively equipped with replenishment ports for spraying water and spraying alkaline solution; the outlets of the fluorinated water washing circulation pump and the alkaline washing circulation pump are also respectively connected to waste discharge pipes leading to the waste liquid pool.

[0007] Furthermore, the outlet of the nitrogen storage tank is also connected to the inlet of a nitrogen dryer, and the outlet of the nitrogen dryer is connected to the fluorination reaction process and the fluorination regeneration process via pipelines.

[0008] Furthermore, the first and second demisters are identical in structure; the demister has a square structure, and a square mounting bracket for placing the demister assembly is provided on the inner wall of the demister. The mounting bracket has a mounting groove for fixing the demister assembly; a hydraulic rod is also provided at the top of the demister, with the fixed end of the hydraulic rod passing through the top of the demister and the bottom of the movable end of the hydraulic rod connected to the top of the demister assembly; the demister assembly is a movable structure, and the hydraulic rod is used to drive the demister assembly to unfold and retract; spray racks for cleaning the demister assembly are provided above and below the demister assembly, and an inlet is provided between the demister assembly and the spray rack below.

[0009] Furthermore, the demisting assembly includes an upper frame, a lower frame, multiple movable frames, and multiple demisting blades; the multiple movable frames are arranged between the upper frame and the lower frame, and adjacent movable frames are hinged by scissor rods symmetrically arranged on the outer walls of both sides of the movable frames. The movable frame at the top is hinged to the upper frame by scissor rods, and the movable frame at the bottom is hinged to the lower frame by scissor rods; the multiple demisting blades are detachably fixed inside the upper frame, the lower frame, and the movable frames; two hydraulic rods are symmetrically arranged, and the bottom of the movable end of the hydraulic rod is connected to the top center of the two side walls of the upper frame.

[0010] Furthermore, the bottom of the lower frame is connected to a plate holder with screw holes. The fixing slot of the fixing frame has the same screw holes on both sides. The plate holder is inserted into the fixing slot, and the locking screw passes through each screw hole from the inside of the fixing frame to fix the plate holder in the fixing slot.

[0011] Furthermore, the defogging blades in the adjacent upper frame, lower frame, and movable frame are arranged at an angle of 0-90° on the same plane projection.

[0012] Furthermore, each spray frame is equipped with multiple nozzles facing the demister assembly; each spray frame is connected to a spray pipe located outside the demister; and the bottom of the demister is also equipped with a cleaning waste liquid outlet.

[0013] Furthermore, the multiple branch pipes in the spray frame below the demisting assembly and the multiple demisting spaces formed between the demisting blades in the lower frame are arranged one-to-one in the same vertical plane.

[0014] The acid removal and recovery system for nitrogen used in the production of refrigerant R134a provided by this utility model can reduce environmental pollution and reduce the consumption of high-purity nitrogen in public systems by removing acid from waste nitrogen containing acid and then recycling it. This is beneficial for energy conservation, emission reduction and lower production costs. The nitrogen recovered to the nitrogen storage tank is a neutral gas with a dew point of <-35℃ and an oxygen content of <50ppm, and the recovery rate reaches more than 80%.

[0015] The demister solves the problem of poor cleaning effect of the demister component by using a hydraulic rod and a liftable demister assembly, which helps to extend the service life of the demister. At the same time, the hydraulic rod drives the demister assembly to lift and lower, adjusting the degree of retraction of the demister assembly. While ensuring the best demister effect, it can also prevent the problem of excessive flow resistance to the fluid caused by an overly compact demister assembly, thus improving the demister effect.

[0016] The frames of the demisting assembly are hinged together by scissor links to form a movable structure that can be raised and lowered. During demisting, the demisting blades inside the frames can intercept impurities and droplets in the nitrogen gas in multiple layers. The demisting blades in different frames can also have different tilt angles. Combined with the demisting blades in the adjacent movable frames arranged at an angle, the turbulence of the fluid during the flow process is increased, thereby increasing the demisting efficiency and gas-liquid separation effect. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the structure of a nitrogen deacidification and recovery system for refrigerant R134a production provided in one embodiment of this utility model;

[0019] Figure 2 This is a schematic diagram of the structure of a demister provided in one embodiment of the present invention;

[0020] Figure 3 An exploded view showing the position of the defogging component and the spray frame below, according to one embodiment of this utility model.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1- Fluorinated water washing tower, 2- Nitrogen recovery alkaline washing tower, 3- Nitrogen buffer tank, 4- Nitrogen compressor, 5- Refrigerated dryer, 6- Nitrogen storage tank, 7- First demister, 8- Second demister, 9- Nitrogen recovery cooler, 10- Nitrogen dryer, 11- Fluorinated water washing circulation pump, 12- Fluorinated water washing cooler, 13- Make-up port, 14- Waste discharge pipe, 21- Alkaline washing circulation pump, 22- Alkaline washing cooler 71-Liquid phase outlet, 72-Fixed frame, 73-Demisting assembly, 74-Hydraulic rod, 75-Spray frame, 76-Cleaning waste liquid outlet, 77-Inlet, 721-Fixed tank, 722-Locking screw, 731-Upper frame, 732-Lower frame, 733-Modible frame, 734-Demisting blade, 735-Scissor linkage, 736-Insert plate frame, 751-Spray pipe, 752-Branch pipe. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are also within the protection scope of this utility model.

[0024] like Figure 1This utility model provides an acid removal and recovery system for nitrogen used in the production of refrigerant R134a, comprising: a fluorinated water scrubbing tower 1, a nitrogen recovery alkaline scrubbing tower 2, a nitrogen buffer tank 3, a nitrogen compressor 4, a refrigerated dryer 5, and a nitrogen storage tank 6 connected sequentially along the nitrogen flow direction; a first demister 7 is provided between the fluorinated water scrubbing tower 1 and the nitrogen recovery alkaline scrubbing tower 2, and the liquid phase outlet 71 at the bottom of the first demister 7 is connected to the return liquid port of the fluorinated water scrubbing tower 1; a second demister 8 is provided between the nitrogen recovery alkaline scrubbing tower 2 and the nitrogen buffer tank 3, and the liquid phase outlet 71 at the bottom of the second demister 8 is connected to the return liquid port of the fluorinated water scrubbing tower 1; 1. The outlet of the nitrogen compressor 4 is connected to the return port of the nitrogen recovery alkaline washing tower 2; the outlet of the nitrogen compressor 4 is also connected to the return port of the nitrogen buffer tank 3, and a nitrogen recovery cooler 9 is provided between the nitrogen compressor 4 and the return port of the nitrogen buffer tank 3; the bottom outlet of the fluorinated water washing tower 1 is connected to the top spray pipe 751 of the fluorinated water washing tower 1 through the fluorinated water washing circulation pump 11 and the fluorinated water washing cooler 12 arranged in sequence; the bottom outlet of the nitrogen recovery alkaline washing tower 2 is connected to the top spray pipe 751 of the nitrogen recovery alkaline washing tower 2 through the alkaline washing circulation pump 21 and the alkaline washing cooler 22 arranged in sequence.

[0025] Waste nitrogen generated during reactor catalyst activation and regeneration, molecular sieve dryer regeneration, and other equipment pipeline replacement is first sent to a fluorinated water scrubbing tower 1 for spray washing to remove solid and water-soluble impurities. After demisting by the first demister 7, the waste nitrogen containing hydrofluoric acid is sent to a nitrogen recovery alkaline scrubbing tower 2 for spray alkaline washing. After acid-base neutralization, it is discharged to the second demister 8 to remove moisture, and then sent to a nitrogen buffer tank 3 for buffering. The alkaline nitrogen containing trace amounts of moisture is then sent to a nitrogen compressor 4 for compression, and then sent to a refrigerated dryer 5 to cool the compressed nitrogen and remove moisture. The resulting high-purity nitrogen with a low dew point temperature is sent to a nitrogen storage tank 6 for reuse in other gas-using processes. The compressed nitrogen discharged from the nitrogen compressor 4 can also be cooled by a nitrogen recovery cooler 9 and then sent back to the nitrogen buffer tank 3, where it is further compressed into high-pressure nitrogen by the nitrogen compressor 4 before storage and use. This acid removal and recovery system removes and recycles previously discharged waste nitrogen, reducing environmental pollution and the amount of high-purity nitrogen used in public systems, which is beneficial for energy conservation, emission reduction and production cost reduction.

[0026] The liquid phase collected in the first demister 7 and the second demister 8 is returned to the fluorinated water scrubbing tower 1 and the nitrogen recovery alkaline scrubbing tower 2 through pipelines, respectively, to avoid affecting the alkaline scrubbing quality and the compressor's operating status. To save costs, the spray water in the fluorinated water scrubbing tower 1 and the spray alkaline solution in the nitrogen recovery alkaline scrubbing tower 2 need to be recycled. However, the waste nitrogen from the regeneration process is at a high temperature, and the spray water and spray alkaline solution also have a cooling effect. Therefore, the spray water and spray alkaline solution need to be cooled by the fluorinated water scrubbing cooler 12 and the alkaline scrubbing cooler 22 during circulation to facilitate heat exchange and cooling of the waste nitrogen during the spraying process.

[0027] Furthermore, the bottoms of the fluorinated water scrubbing tower 1 and the nitrogen recovery alkaline scrubbing tower 2 are respectively equipped with replenishment ports 13 for supplementing the spray water and spray alkali solution; the outlets of the fluorinated water scrubbing circulating pump 11 and the alkali scrubbing circulating pump 21 are also respectively connected to waste discharge pipes 14 leading to the waste liquid pool. The spray alkali solution used in the nitrogen recovery alkaline scrubbing tower 2 is usually a 32% sodium hydroxide solution. During the operation of the fluorinated water scrubbing tower 1 and the nitrogen recovery alkaline scrubbing tower 2, the spray water and spray alkali solution may decrease due to evaporation or airflow entrainment, which can be replenished through the replenishment ports 13. Similarly, when the circulating spray water and spray alkali solution absorb a large amount of impurities or have a high acid content, they are discharged into the waste liquid pool through the waste discharge pipe 14, and new spray water and spray alkali solution are added to improve the spray washing effect; or during maintenance, they are discharged into the waste liquid pool through the waste discharge pipe 14, providing convenience for maintenance work.

[0028] Furthermore, the outlet of the nitrogen storage tank 6 is also connected to the inlet of the nitrogen dryer 10, and the outlet of the nitrogen dryer 10 is connected to the fluorination reaction process and the fluorination regeneration process via pipelines. The outlet of the nitrogen dryer 10 can also be connected to other gas-using processes. The nitrogen dryer 10 can use molecular sieve adsorption drying or other drying methods to dehumidify, thereby reducing the moisture in the high-purity nitrogen from the nitrogen storage tank 6, thus facilitating its use.

[0029] After a period of use, the demister is rinsed with water using a spray frame 75 to remove impurities adhering to it. However, because existing demister components 73 are often multi-layered, the rinsing water cannot fully contact the components due to high resistance, resulting in poor cleaning. Long-term retention of impurities reduces the demister's lifespan and demister performance. Therefore, if... Figure 2 The first demister 7 and the second demister 8 are demisters with the same structure. The demister has a square structure, and a square fixing frame 72 for placing the demister assembly 73 is provided on the inner wall of the demister. The fixing frame 72 has a fixing groove 721 for fixing the demister assembly 73. The top of the demister is also provided with a hydraulic rod 74. The fixed end of the hydraulic rod 74 passes through the top of the demister, and the bottom of the movable end of the hydraulic rod 74 is connected to the top of the demister assembly 73. The demister assembly 73 is a movable structure, and the hydraulic rod 74 is used to drive the demister assembly 73 to unfold and retract. Spray racks 75 for cleaning the demister assembly 73 are provided above and below the demister assembly 73. An inlet 77 is provided between the demister assembly 73 and the spray rack 75 below.

[0030] The demister assembly 73 is designed as a movable structure that can be expanded and retracted. The hydraulic rod 74 can be used to raise and lower the demister assembly 73 according to the demister load. By adjusting the degree of retraction of the demister assembly 73, optimal demister performance can be achieved while preventing excessive flow resistance caused by an overly compact assembly. When cleaning is required, the hydraulic rod 74 expands the demister assembly 73 to its maximum extent, allowing the flushing water to fully contact and clean the assembly in a looser environment. This reduces the flow resistance of the flushing water, allowing wastewater and attached impurities to flow down quickly, improving the cleaning effect and extending the service life of the demister. For convenient drainage, the bottom of the demister can be designed as an arc or inverted cone shape, with the liquid outlet 71 located at the center of the bottom.

[0031] like Figure 2 and Figure 3 Furthermore, the demisting assembly 73 includes an upper frame 731, a lower frame 732, multiple movable frames 733, and multiple demisting blades 734; the multiple movable frames 733 are disposed between the upper frame 731 and the lower frame 732, and adjacent movable frames 733 are hinged by scissor rods 735 symmetrically disposed on the outer walls of both sides of the movable frame 733; the movable frame 733 at the top is hinged to the upper frame 731 by the scissor rods 735, and the movable frame 733 at the bottom is hinged to the lower frame 732 by the scissor rods 735; the multiple demisting blades 734 are detachably fixed inside the upper frame 731, the lower frame 732, and the movable frames 733; two hydraulic rods 74 are symmetrically disposed, and the bottom of the movable end of the hydraulic rod 74 is connected to the top center of the two side walls of the upper frame 731.

[0032] The scissor linkage 735 includes multiple X-shaped connecting rods, the ends of which are sequentially hinged to each other. The X-shaped connecting rods can extend and retract in a scissor-like manner through the hinge points. Each X-shaped connecting rod includes two movable rods that are hinged in the middle. The middle hinge point of the two movable rods is connected to the side walls of the upper frame 731, the lower frame 732, and multiple movable frames 733.

[0033] During the lifting and lowering of the scissor linkage 735, the lower frame 732 remains fixed, while the upper frame 731 and multiple movable frames 733 rise and fall accordingly to stack or extend the individual frames.

[0034] The frames, placed vertically, are hinged together by scissor rods 735, forming a liftable and movable structure. During demisting, the frames can be stacked using hydraulic rods 74, allowing the demisting blades 734 inside the frames to intercept impurities and droplets in the nitrogen gas in multiple layers. The demisting effect is not significantly different from that of a conventional fixed structure. Alternatively, angles can be formed between the frames, resulting in different tilt angles between the demisting blades 734 in different frames, increasing the turbulence of the fluid during flow and thus improving demisting efficiency and effect. During cleaning, the frames are spread out as much as possible using hydraulic rods 74, reducing the flow resistance of the rinsing water and improving the cleaning effect. Corresponding to the demister structure, the upper frame 731, lower frame 732, and movable frame 733 are all square structures, facilitating the lifting, installation, and disassembly of the demisting assembly 73.

[0035] The shape of the demisting blades 734 is not limited; they can be V-shaped, sinusoidal, ridge-shaped, or other shapes commonly used in the art. Demisting spaces are provided between adjacent demisting blades 734, and the spacing between these spaces can be the same or different. When nitrogen gas flows through the demisting assembly 73, it is diverted into the demisting spaces by the demisting blades 734. Liquid droplets entrained in the nitrogen gas collide with the demisting blades 734 and flow downwards along them under gravity, thus separating the gas and liquid and achieving a good demisting effect.

[0036] like Figure 2 and Figure 3 Furthermore, a plate holder 736 is connected to the bottom of the lower frame 732. The plate holder 736 has screw holes, and the fixing slot 721 of the fixing frame 72 has the same screw holes on both sides. The plate holder 736 is inserted into the fixing slot 721, and the locking screw 722 passes through each screw hole from the inside of the fixing frame 72 to fix the plate holder 736 in the fixing slot 721. Through the cooperation of the plate holder 736 and the fixing slot 721, the defogging component 73 can be more conveniently and detachably positioned on the fixing frame 72 using the locking screw 722, so that the lower frame 732 can always remain fixed when the defogging component 73 is unfolded or retracted under the action of the hydraulic rod 74.

[0037] like Figure 3 The demister blades 734 in the upper frame 731, lower frame 732, and movable frame 733, which are adjacent to each other, are arranged at an angle of 0-90° on the same plane projection. The angled arrangement of the demister blades 734 in the adjacent movable frame 733 changes the conventional parallel arrangement, which continuously alters the flow path of the airflow as it passes through the movable frame 733. The airflow is constantly changing direction, increasing the degree of airflow turbulence, which in turn increases the chance of entrained droplets colliding with the demister blades 734, reducing the droplet escape rate, and thus further improving the gas-liquid separation effect and demister efficiency.

[0038] like Figure 2 Furthermore, each spray frame 75 is equipped with multiple nozzles facing the demister assembly 73; each spray frame 75 is connected to a spray pipe 751 located outside the demister; and the bottom of the demister is also equipped with a cleaning waste liquid outlet 76. Since the waste nitrogen gas contains relatively few solid impurities, the nozzles on the lower spray frame 75 are unlikely to be clogged by the liquid phase from the demister assembly 73. Therefore, installing spray frames 75 and nozzles above and below the demister assembly 73 improves the cleaning effect of the demister assembly 73. The style of the spray frame 75 is not limited; it can be round, square, or other shapes, as long as the rinsing water sprayed from the nozzles can cover the entire demister assembly 73.

[0039] like Figure 3 The multiple branch pipes 752 in the spray frame 75 below the demisting assembly 73 and the multiple demisting spaces formed between them and the demisting blades 734 in the lower frame 732 are arranged one-to-one in the same vertical plane. Preferably, the spray frame 75 below the demisting assembly 73 is square. Arranging the multiple branch pipes 752 in the spray frame 75 and the demisting blades 734 in the lower frame 732 in the same vertical plane in a one-to-one correspondence facilitates targeted rinsing of the contact surface between each demisting blade 734 and the airflow during demisting, while also allowing the demisting spaces to access the upper movable frame 733 for rinsing.

[0040] This invention relates to a nitrogen deacidification and recovery system for refrigerant R134a production. In operation, waste nitrogen generated during reactor catalyst activation and regeneration, molecular sieve dryer regeneration, and other equipment pipeline replacement is first sent to a fluorination water scrubbing tower 1 for spray washing to remove solid and water-soluble impurities. The pressure of the fluorination water scrubbing tower 1 is controlled at 50-70 kPa, and the temperature at 25-35℃. The washed waste nitrogen is then demisted by a first demister 7. The liquid phase collected in the first demister 7 is returned to the fluorination water scrubbing tower 1 through pipelines, while the gas phase is discharged. Waste nitrogen containing hydrofluoric acid is then sent to a nitrogen recovery alkaline scrubbing tower 2, where it is sprayed with a 32% sodium hydroxide solution. The pressure of the nitrogen recovery alkaline scrubbing tower 2 is controlled at 50-70 kPa, and the temperature at 25-35℃. After acid-base neutralization, the solution is discharged to the second demister 8 to remove moisture. The liquid phase collected in the second demister 8 is returned to the nitrogen recovery alkaline washing tower 2 through pipelines, while the gas phase is discharged. The spray water and spray alkaline solution are recycled, and during circulation, they are cooled by a fluorinated water wash cooler 12 and an alkaline wash cooler 22 to facilitate heat exchange and cooling of the waste nitrogen during spraying. The pH value of the spray alkaline solution is monitored by an instrument to ensure it is maintained above 12, and fresh spray alkaline solution can be replenished at any time through the replenishment port 13.

[0041] After alkaline washing, the nitrogen gas is sent to nitrogen buffer tank 3 for buffering. Then, the alkaline nitrogen gas containing trace amounts of moisture is compressed by nitrogen compressor 4. The outlet pressure of nitrogen compressor 4 is controlled above 0.3 MPa. The compressed nitrogen gas is then sent to refrigerated dryer 5 for cooling and moisture removal. The outlet temperature of refrigerated dryer 5 is 26-35℃, and the moisture content is controlled below 10 ppm. The resulting high-purity nitrogen gas with a low dew point temperature is sent to nitrogen storage tank 6. The compressed nitrogen gas discharged from nitrogen compressor 4 can also be cooled by nitrogen recovery cooler 9 and then sent back to nitrogen buffer tank 3. It is then further compressed into high-pressure nitrogen gas by nitrogen compressor 4 before storage and use. The high-purity nitrogen gas in nitrogen storage tank 6 is dried by nitrogen dryer 10 and then supplied to the fluorination reaction process, fluorination regeneration process, and other gas-using processes for reuse.

[0042] In the first demister 7 and the second demister 8, the demister assembly 73 can be more conveniently and detachably positioned on the fixed frame 72 by means of the cooperation of the insert plate frame 736 and the fixing groove 721, using the locking screw 722. The upper frame 731, lower frame 732 and multiple movable frames 733, placed vertically, are hinged together by scissor rods 735 to form a liftable demister assembly 73. During demister operation, the upper frame 731, lower frame 732 and multiple movable frames 733 are stacked by hydraulic rods 74. The demister blades 734 inside each frame intercept impurities and droplets in the nitrogen gas in multiple layers. An angle can also be formed between the frames to increase the turbulence of the fluid during flow. While ensuring the best demister effect, it can also prevent the problem of excessive flow resistance caused by the overly compact demister assembly 73, thereby increasing the demister efficiency and effect. When the demisting blades 734 need to be cleaned, the hydraulic rods 74 are used to spread the frames as far apart as possible, so that the flushing water can fully contact and clean the demisting assembly 73 in a looser environment, and the flow resistance of the flushing water is reduced, thus improving the cleaning effect of the demisting assembly 73.

[0043] It should be noted that the detailed structure of some devices in this utility model is not described in detail, but belongs to the prior art known to those skilled in the art, and therefore will not be described again here. In addition, the parts of this device not described are the same as or can be implemented using existing technology.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. An acid removal recovery system for nitrogen gas used in production of refrigerant R134a, characterized by, The application relates to a nitrogen recovery and fluoride washing system. The nitrogen recovery and fluoride washing system comprises a fluoride washing tower, a nitrogen recovery and alkali washing tower, a nitrogen buffer tank, a nitrogen compressor, a refrigeration dryer and a nitrogen storage tank which are sequentially connected along the nitrogen flow direction; a first mist eliminator is arranged between the fluoride washing tower and the nitrogen recovery and alkali washing tower, a liquid phase outlet at the bottom of the first mist eliminator is connected with a liquid return port of the fluoride washing tower; a second mist eliminator is arranged between the nitrogen recovery and alkali washing tower and the nitrogen buffer tank, a liquid phase outlet at the bottom of the second mist eliminator is connected with a liquid return port of the nitrogen recovery and alkali washing tower; an outlet of the nitrogen compressor is also connected with a gas return port of the nitrogen buffer tank, and a nitrogen recovery cooler is further arranged between the nitrogen compressor and the gas return port of the nitrogen buffer tank; A fluoride washing circulating pump and a fluoride washing cooler are sequentially arranged at a tower bottom outlet of the fluoride washing tower and connected with a tower top spraying pipeline of the fluoride washing tower; an alkali washing circulating pump and an alkali washing cooler are sequentially arranged at a tower bottom outlet of the nitrogen recovery and alkali washing tower and connected with a tower top spraying pipeline of the nitrogen recovery and alkali washing tower.

2. The acid removal recovery system for producing refrigerant R134a with nitrogen gas according to claim 1, characterized by, A liquid supplementing port for supplementing spraying water and spraying alkali liquid is arranged at a tower kettle of the fluoride washing tower and the nitrogen recovery and alkali washing tower respectively; an outlet of the fluoride washing circulating pump and the alkali washing circulating pump is further connected with a waste liquid discharge pipeline leading to a waste liquid pool respectively.

3. The acid removal recovery system for producing refrigerant R134a with nitrogen gas according to claim 1, characterized by, An outlet of the nitrogen storage tank is further connected with an inlet of a nitrogen dryer, and an outlet of the nitrogen dryer is connected with a fluoride reaction process and a fluoride regeneration process through pipelines respectively.

4. The deacidification recovery system for producing nitrogen gas for refrigerant R134a according to any one of claims 1 to 3, characterized by, The first mist eliminator and the second mist eliminator are mist eliminators with the same structure; the mist eliminator has a square structure, a square fixing frame for placing a mist eliminating assembly is arranged on an inner wall of the mist eliminator, and a fixing groove for fixing the mist eliminating assembly is arranged in the fixing frame; a hydraulic rod is further arranged at the top of the mist eliminator, a fixed end of the hydraulic rod penetrates through the top of the mist eliminator, and a movable end of the hydraulic rod is connected with the top of the mist eliminating assembly; the mist eliminating assembly has a movable structure, and the hydraulic rod is used for driving the mist eliminating assembly to expand and contract; a spraying frame for cleaning the mist eliminating assembly is arranged above and below the mist eliminating assembly, and an inlet is arranged between the mist eliminating assembly and the spraying frame below.

5. The acid removal recovery system for producing the refrigerant R134a with nitrogen gas according to claim 4, characterized by, The mist eliminating assembly comprises an upper frame, a lower frame, a plurality of movable frames and a plurality of mist eliminating blades; the movable frames are arranged between the upper frame and the lower frame, and adjacent movable frames are hingedly connected through scissor links symmetrically arranged on both side outer walls of the movable frames; the movable frame at the top is hingedly connected with the upper frame through the scissor links, and the movable frame at the bottom is hingedly connected with the lower frame through the scissor links; the mist eliminating blades are detachably fixed in the upper frame, the lower frame and the movable frames; two hydraulic rods are symmetrically arranged, and movable end bottoms of the hydraulic rods are connected with the top centers of the two side walls of the upper frame.

6. The acid removal recovery system for producing refrigerant R134a with nitrogen gas according to claim 5, characterized by, The bottom of the lower frame is connected with an inserting plate frame, screw holes are formed in the inserting plate frame, the same screw holes are formed in the two sides of the fixing groove of the fixing frame, the inserting plate frame is inserted into the fixing groove, and locking screws are sequentially penetrated through each screw hole from the inside of the fixing frame to fix the inserting plate frame in the fixing groove.

7. The acid removal recovery system for producing refrigerant R134a with nitrogen gas according to claim 5, characterized by, The demisting blades in the upper frame, the lower frame and the movable frame adjacent to each other are arranged at an angle of 0-90° on the same plane projection.

8. The acid removal recovery system for producing refrigerant R134a with nitrogen gas according to claim 5, characterized by, A plurality of spray heads are arranged on each spray frame and face the demisting assembly; each spray frame is connected with a spray pipeline arranged outside the demister; and a cleaning waste liquid outlet is further arranged at the bottom of the demister.

9. The acid removal recovery system for producing refrigerant R134a with nitrogen gas according to claim 8, characterized by, A plurality of demisting spaces are formed between a plurality of branch pipes in the spray frame below the demisting assembly and the demisting blades in the lower frame, and the branch pipes are arranged in the same vertical plane one-to-one corresponding to the demisting spaces.

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