Device for deep defluorination of phosphoric acid

Abstract

The utility model discloses a device for deep defluorination of phosphoric acid, relates to the field of phosphoric acid defluorination equipment, and aims to realize deep removal of fluorine impurities in phosphoric acid. According to the device, a second defluorination structure mainly composed of a liquid-phase redistributor and a spraying assembly is arranged in a tower body, and a gas-phase barrel is arranged on a first tower plate of the liquid-phase redistributor, so that the liquid-phase redistributor can be ensured to be capable of defluorinating on the premise of not hindering upward flowing of gas; the phosphoric acid subjected to defluorination through the first defluorination structure is collected in a liquid phase redistribution tank; meanwhile, the continuous-phase phosphoric acid collected in the liquid-phase redistribution tank can be sprayed into the defluorination cavity section on the lower side of the first tower plate in a pressurized spraying manner through the spraying assembly, so that the high-viscosity phosphoric acid is dispersed into the gas phase in the form of tiny liquid drops, more liquid-phase mass transfer interfaces are provided, the mass transfer resistance of fluorine impurities in the phosphoric acid is reduced, and the defluorination effect is improved. Therefore, fluorine impurities in phosphoric acid can be deeply removed, and the product quality is ensured.

Description

Technical Field

[0001] This utility model belongs to the field of phosphoric acid defluorination equipment, specifically relating to a device for deep defluorination of phosphoric acid. Background Technology

[0002] Phosphoric acid defluorination methods can be divided into wet phosphoric acid defluorination and purified phosphoric acid defluorination, depending on the phosphoric acid raw material. The former is mainly used to prepare feed-grade dicalcium phosphate, while the latter is mainly used to produce food-grade phosphoric acid. Both wet and purified phosphoric acid defluorination operate on the principle of stripping defluorination using hot air or superheated steam. Currently, the equipment used for industrial phosphoric acid stripping defluorination is the bubble cap tower. A bubble cap tower is a plate tower where liquid phosphoric acid flows continuously through a plate defluorination structure, while the gas phase enters the liquid phosphoric acid as a dispersed phase through bubbling for defluorination.

[0003] For example, Chinese utility model patent CN214763403U discloses a bubble cap tower for wet-process phosphate residue acid defluorination. The bubble cap tower includes a hollow tower body with an outlet at the top. The tower body has multiple layers of trays from top to bottom, each tray has multiple bubble caps, and a downcomer is provided at the bottom of the tray. Adjacent trays are connected by the downcomer. An inlet pipe is provided above the top tray, and a baffle is provided below the bottom tray. An outlet pipe is provided on the baffle, and a steam inlet pipe is provided above the baffle. A bottom plate is inclined below the baffle, and an outlet is provided at the lowest point of the bottom plate.

[0004] The aforementioned bubble cap tower uses multiple layers of bubble-capped trays with a steam inlet pipe below each tray. Steam heats the sludge acid mixed with a defluorinating agent, keeping it in a boiling state within the tower. The escaping fluorine-containing gas is discharged through the outlet, effectively purifying the sludge acid and achieving continuous defluorination, facilitating industrial production. However, due to the high viscosity of phosphoric acid, its continuous flow through the trays for defluorination makes deep removal of fluorine impurities difficult, frequently resulting in fluctuations in the fluorine content of the product and substandard product quality. Furthermore, the bubble-cap method of dispersing the gas phase results in a small mass transfer interface and poor mass transfer, leading to low defluorination efficiency in the bubble cap tower.

[0005] Therefore, there is an urgent need in this field for a phosphoric acid defluorination device to solve the problems of insufficient defluorination depth and low efficiency of existing bubble cap towers. Utility Model Content

[0006] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention provides an apparatus for deep defluorination of phosphoric acid, which can achieve deep removal of fluorine impurities from phosphoric acid.

[0007] The utility model discloses a technical scheme that solves its technical problem is: for the device of phosphoric acid deep defluorination, including tower body, liquid inlet mechanism, first defluorination structure and air inlet mechanism,

[0008] The inner chamber of the tower body is a tower cavity, which is sequentially divided into a liquid inlet cavity section, a defluorination cavity section and an air inlet cavity section from top to bottom.

[0009] The liquid inlet mechanism is arranged on the tower body, and its liquid outlet part is located in the liquid inlet cavity section.

[0010] The first defluorination structure is a packing defluorination structure or a plate-type defluorination structure, which is arranged in the defluorination cavity section.

[0011] The air inlet mechanism is arranged on the tower body, and its air outlet part is located in the air inlet cavity section.

[0012] The second defluorination structure further comprises a liquid phase redistributor and a spraying assembly.

[0013] The liquid phase redistributor comprises a first tray arranged in the defluorination cavity section and located at the lower side of the first defluorination structure, and a gas phase cylinder arranged on the first tray; the defluorination cavity section between the upper end of the gas phase cylinder and the upper surface of the first tray forms a liquid phase redistribution groove; the cylinder cavity of the gas phase cylinder is a gas phase passage, which communicates the defluorination cavity sections on the upper and lower sides of the first tray.

[0014] The spraying assembly comprises a liquid pressurizing pump arranged outside the tower body, a spraying head arranged in the defluorination cavity section and located at the lower side of the first tray, a liquid inlet pipe for connecting the liquid inlet of the liquid pressurizing pump with the liquid phase redistribution groove, and a liquid outlet pipe for connecting the liquid outlet of the liquid pressurizing pump with the liquid inlet of the spraying head.

[0015] Further, the second defluorination structure further comprises a first liquid level interlocking system, which comprises a first liquid level monitoring meter and a first liquid level controller.

[0016] The first liquid level monitoring meter is arranged in the liquid phase redistribution groove and used for monitoring the liquid level height in the liquid phase redistribution groove.

[0017] The first liquid level controller is communicatively connected with the first liquid level monitoring meter and the liquid pressurizing pump; when the first liquid level monitoring meter detects that the liquid level in the liquid phase redistribution groove exceeds the set upper limit of the liquid level, the first liquid level controller can control the liquid pressurizing pump to increase the output power so as to increase the liquid flow in the spraying assembly; when the first liquid level monitoring meter detects that the liquid level in the liquid phase redistribution groove is lower than the set lower limit of the liquid level, the first liquid level controller can control the liquid pressurizing pump to reduce the output power so as to reduce the liquid flow in the spraying assembly.

[0018] Further, the liquid inlet mechanism comprises a liquid phase distributor and a tower body liquid inlet;

[0019] The liquid phase distributor comprises at least two annular pipes with different diameters and arranged concentrically, and a central pipe in communication with each annular pipe;

[0020] The lower edge of the annular pipe is provided with at least two uniformly distributed liquid outlet holes, and the annular pipe with a smaller diameter is provided with a smaller liquid outlet hole; The liquid outlet holes on each annular pipe together form the liquid outlet part of the liquid inlet mechanism;

[0021] The tower body liquid inlet is arranged on the side of the tower body, and the liquid inlet of the liquid phase distributor is connected with the tower body liquid inlet.

[0022] Further, the central pipe is a "cross" pipe comprising two intersecting connection pipes in communication with each other, both of which are in communication with each annular pipe, and a central liquid inlet is arranged at the intersection of the two connection pipes, which is the liquid inlet of the liquid phase distributor.

[0023] Further, the gas inlet mechanism comprises a tower body gas inlet and a gas phase distributor;

[0024] The tower body gas inlet is arranged on the side of the tower body;

[0025] The gas phase distributor comprises a gas inlet main pipe arranged in the gas inlet cavity section and connected with the tower body gas inlet, and a gas inlet branch pipe arranged on the gas inlet main pipe and in communication therewith;

[0026] The upper edge of the gas inlet branch pipe is provided with at least two uniformly distributed gas outlet holes, and each gas outlet hole together forms the gas outlet part of the gas inlet mechanism.

[0027] Further, the gas inlet main pipe is arranged along the radial direction of the tower body;

[0028] The gas inlet branch pipe is at least two, and is arranged along the axial direction of the gas inlet main pipe; the gas inlet branch pipe is perpendicular to the gas inlet main pipe, and the length of the gas inlet branch pipe closer to the central axis of the tower body is longer.

[0029] Further, the device further comprises a second liquid level interlocking system, which comprises a second liquid level monitor, a liquid discharge pump and a second liquid level controller;

[0030] The second liquid level monitor is arranged in the gas inlet cavity section for monitoring the liquid level height in the gas inlet cavity section;

[0031] The liquid discharge pump is arranged outside the tower body, and its liquid inlet is connected with the tower body liquid outlet through a discharge pipeline;

[0032] The second liquid level controller is in communication connection with the second liquid level monitor and the liquid discharge pump respectively; the second liquid level controller can control the liquid discharge pump to increase or decrease the output power when the second liquid level monitor detects that the liquid level in the air inlet cavity section is not in the set discharge height range.

[0033] Further, the plate type defluorination structure comprises at least two second trays which are arranged in an upper and lower interval in the defluorination cavity section, and a cofferdam is arranged on the upper surface of the second tray, which separates the area on the upper side of the second tray into a defluorination zone and an overflow zone.

[0034] A gas phase redistribution device is arranged on the second tray corresponding to the defluorination zone, which has a gas phase redistribution inlet in communication connection with the defluorination cavity section on the lower side of the second tray and a gas phase redistribution outlet in communication connection with the defluorination zone.

[0035] Any two adjacent second trays, the overflow zone of the second tray on the upper side is in communication connection with the defluorination zone of the second tray on the lower side through a downcomer; the overflow zone of the second tray on the lowermost side is in communication connection with the liquid phase redistribution tank through a downcomer.

[0036] Further, at least two regularly distributed gas phase cylinders are arranged on the first tray.

[0037] At least two regularly distributed gas phase redistribution devices are arranged on the second tray.

[0038] Further, the gas phase redistribution device is a cylindrical cover with a closed upper end and an open lower end, and at least two uniformly distributed gas phase redistribution outlets are arranged on the sidewall of the cylindrical cover.

[0039] The beneficial effects of the utility model are as follows:

[0040] 1) The device is provided with a second defluorination structure mainly composed of a liquid phase redistribution device and a spraying assembly, and a gas phase cylinder is arranged on the first tray of the liquid phase redistribution device, so that the liquid phase redistribution device can collect the phosphoric acid after defluorination by the first defluorination structure in the liquid phase redistribution tank without hindering the upward flow of the gas; at the same time, the continuous phase state phosphoric acid collected in the liquid phase redistribution tank can be sprayed into the defluorination cavity section on the lower side of the first tray in the form of pressurized spraying through the spraying assembly, so that the high-viscosity phosphoric acid is dispersed into the gas phase in the form of tiny droplets, more liquid phase mass transfer interfaces are provided, the mass transfer resistance of the fluorine impurities in the phosphoric acid is reduced, the mass transfer of the fluorine impurities in the phosphoric acid is greatly intensified, the fluorine impurities in the phosphoric acid can be deeply removed, and the quality of the product is ensured.

[0041] 2) Compared with the existing bubble column, one of the embodiments of the utility model takes the packing defluorination structure as the first defluorination structure, can make gas-liquid two-phase flow dispersion by packing, and provides larger mass transfer interface, is favorable to improve defluorination efficiency, and can make the gas bubble floating rate slow down, the gas-liquid contact time is longer, and is further favorable to defluorination mass transfer.

[0042] 3) Compared with the existing bubble column, another embodiment of the utility model takes the plate type defluorination structure with the gas phase redistributor as the first defluorination structure, a plurality of uniformly distributed gas phase redistribution gas outlet holes are formed on the gas phase redistributor, can more effectively disperse the gas phase, makes the gas phase enter the phosphoric acid in the defluorination area with smaller scale bubble, can provide larger mass transfer interface, and the small bubble floating rate is slower, the gas-liquid contact time is longer, is favorable to defluorination mass transfer, and improves the defluorination effect.

[0043] 4) The gas phase is dispersed by packing or a plurality of uniformly distributed gas phase redistribution gas outlet holes, can greatly strengthen mass transfer, makes the mass transfer distance in the gas phase greatly shorten, reduces the gas amount required for defluorination of the device, obtains high concentration fluorine-containing gas phase after defluorination, is favorable to subsequent recovery, and also reduces production cost.

[0044] The technical effects brought by other technical features of the utility model or directly generated will be described in detail in the subsequent specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 It is the implementation structure schematic diagram of one embodiment of the utility model;

[0046] Figure 2 It is the overhead structure schematic diagram of liquid phase redistributor;

[0047] Figure 3 It is the bottom structure schematic diagram of liquid phase distributor;

[0048] Figure 4 It is the overhead structure schematic diagram of gas phase distributor;

[0049] Figure 5 It is the implementation structure schematic diagram of another embodiment of the utility model;

[0050] Figure 6 It is the overhead structure schematic diagram of one layer of plate type defluorination structure;

[0051] Figure 7 It is the sectional view of gas phase redistributor;

[0052] 100-tower body, 101-tower body gas outlet, 102-tower body liquid outlet, 210-liquid phase redistributor, 211-first tray, 212-gas phase cylinder, 213-liquid phase redistribution groove, 220-spray assembly, 221-liquid pressurizing pump, 222-spray head, 223-liquid inlet pipe, 224-liquid outlet pipe, 310-liquid phase distributor, 311-ring pipe, 312-center pipe, 313-liquid outlet hole, 320-tower body liquid inlet, 400-defluorination structure of packing, 510-second tray, 511-defluorination zone, 512-overflow zone, 520-dyke, 530-gas phase redistributor, 531-gas phase redistribution gas inlet, 532-gas phase redistribution gas outlet hole, 540-downcomer, 610-tower body gas inlet, 620-gas phase distributor, 621-gas inlet main pipe, 622-gas inlet branch pipe, 623-gas outlet hole, 710-liquid outlet pump, 720-outlet pipeline;

[0053] Figure 7 The directions indicated by the plurality of free arrows represent the directions of the gas phase flowing from the gas phase redistribution gas inlet into the gas phase redistributor and then flowing out of the gas phase redistribution gas outlet hole. DETAILED DESCRIPTION

[0054] The utility model will be further described below in combination with the drawings and examples. The same reference signs in the drawings represent functionally identical or similar parts. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

[0055] In the description of the utility model, it should be understood that the orientations or positions, dimensional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description, and do not indicate or imply that the devices or parts referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.

[0056] In the description of this utility model, the term "communication connection" refers to the communication established between connected devices through signal transmission and interaction, which can be divided into wired connection and wireless connection; wired connection is usually a cable, fiber optic, etc.; wireless connection is usually a radio communication, Bluetooth, infrared, NFC, etc. When the term "many" indicates a quantity, it usually refers to a quantity of three or more, for example, "multiple" usually means three or more. The expression "mainly composed of or constituted by" is interpreted as also including structural components not mentioned in the sentence. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0057] like Figure 1 or Figure 5 As shown, the device for deep defluorination of phosphoric acid includes a tower body 100, a liquid inlet mechanism, a first defluorination structure, a gas inlet mechanism, and a second defluorination structure.

[0058] The tower body 100 is the main component of the device, primarily used to provide defluorination space. The tower body 100 generally consists of a tower shell and a tower lining installed on the inner wall of the tower shell. The tower shell is usually made of stainless steel, preferably 304 or 316L stainless steel. The tower lining is preferably made of polytetrafluoroethylene. The inner cavity of the tower body 100 is called the tower cavity, which is divided into a liquid inlet section, a defluorination section, and an air inlet section from top to bottom. The top of the tower body 100 has a tower outlet 101 communicating with the tower cavity, and the bottom of the tower body 100 has a tower liquid outlet 102 communicating with the tower cavity.

[0059] The liquid inlet mechanism is installed on the tower body 100, and its liquid outlet is located in the liquid inlet section; the liquid inlet mechanism is mainly used to transport phosphoric acid that needs to be defluorinated into the tower cavity;

[0060] The first defluorination structure is either a packed defluorination structure 400 or a plate defluorination structure, which is set in the defluorination chamber to increase the mass transfer interface between the gas and liquid phases in order to remove fluorine impurities from phosphoric acid.

[0061] The air inlet mechanism is installed on the tower body 100, and its air outlet is located in the air inlet section; the air inlet mechanism is mainly used to transport hot air or superheated steam and other gaseous phases into the liquid inlet section of the tower cavity;

[0062] The second defluorination structure is used to deeply remove fluorine impurities from phosphoric acid, and it includes a liquid phase redistributor 210 and a spray assembly 220.

[0063] The liquid phase redistributor 210 comprises a first tray 211 arranged in the defluorination cavity section and at the lower side of the first defluorination structure, and a gas phase cylinder 212 arranged on the first tray 211; the upper end of the gas phase cylinder 212 to the upper surface of the first tray 211 forms a liquid phase redistribution groove 213 in the defluorination cavity section; the cylinder cavity of the gas phase cylinder 212 is a gas phase passage that connects the defluorination cavity sections on both sides of the first tray 211; the first tray 211 is generally arranged transversely in the defluorination cavity section, preferably transversely across the tower cavity; the gas phase cylinder 212 is used to pass through the defluorination cavity section interrupted by the first tray 211 to ensure the flow of gas; the number and size of the gas phase cylinder 212 can be set as needed; by arranging the gas phase cylinder 212 on the first tray 211, the liquid phase redistributor 210 can collect the phosphoric acid defluorinated by the first defluorination structure in the liquid phase redistribution groove 213 without hindering the upward flow of gas; the liquid phase redistributor 210 is generally made of corrosion-resistant materials, preferably the main body is made of stainless steel and the outer lining is made of polytetrafluoroethylene; the stainless steel used to make the main body of the liquid phase redistributor 210 is preferably 304 or 316L stainless steel; a liquid discharge port is generally provided at the bottom or lower part of the side wall of the liquid phase redistribution groove 213;

[0064] The spray assembly 220 comprises a liquid pressurizing pump 221 arranged outside the tower body 100, a spray head 222 arranged in the defluorination cavity section and at the lower side of the first tray 211, a liquid inlet pipe 223 connecting the liquid inlet of the liquid pressurizing pump 221 with the liquid phase redistribution groove 213, and a liquid outlet pipe 224 connecting the liquid outlet of the liquid pressurizing pump 221 with the liquid inlet of the spray head 222; the liquid pressurizing pump 221 is mainly used to transport and increase the pressure of the phosphoric acid, so that it can finally be sprayed out of the spray head 222; the liquid pressurizing pump 221 can be of various types, and is preferably a frequency-adjustable plunger pump, the main body of which is preferably made of one of 316L, 2205 and 904 stainless steel, and the diaphragm thereof is preferably made of perfluoroether; the liquid inlet of the liquid inlet pipe 223 is generally connected with the liquid discharge port of the liquid phase redistribution groove 213; the spray head 222 is mainly used to spray the high-viscosity phosphoric acid in the form of tiny droplets into the defluorination cavity section at the lower side of the first tray 211, so as to provide more liquid phase mass transfer interfaces and reduce the mass transfer resistance of the fluorine impurities in the phosphoric acid; the spray head 222 is generally made of corrosion-resistant materials, preferably the main body is made of stainless steel and the outer lining is made of polytetrafluoroethylene; the stainless steel used to make the main body of the spray head 222 is preferably 2205 or 904 stainless steel.

[0065] In order to ensure that the gas phase can pass through the liquid phase redistributor 210 more smoothly, in combination with Figure 1 and Figure 2 or in combination with Figure 2 and Figure 5As shown, in some embodiments, at least two regularly distributed gas phase cylinders 212 are arranged on the first tray 211. The gas phase cylinders 212 can be regularly distributed on the first tray 211 in various ways, such as: equidistantly distributed side by side, arranged in a straight line, arranged in a triangle, arranged in a circular array, and the like; wherein the arrangement in a straight line is equivalent to the rectangular array distribution; the triangle arrangement refers to that multiple rows of gas phase cylinders 212 are arranged side by side, and any two adjacent rows of gas phase cylinders 212 are staggered with respect to each other, such as Figure 2 As shown.

[0066] In order to further improve the smoothness of the gas phase flow, in some embodiments, the distance between any two adjacent gas phase cylinders 212 is preferably 1-2 times the inner diameter of the gas phase cylinder 212. The distance between the two adjacent gas phase cylinders 212 generally refers to the shortest distance between the outer walls of the two.

[0067] In some embodiments, the gas phase cylinder 212 is a vertically arranged cylinder, both the upper end and the lower end of which are open to allow the gas phase to flow. The gas phase cylinder 212 has simple structure, is easy to install, and has good flow effect.

[0068] Preferably, the height of the gas phase cylinder 212 is 200-300 mm, and the inner diameter is 50-80 mm. The gas phase cylinder 212 with such size and structure, when regularly distributed on the first tray 211, can achieve good liquid phase redistribution effect and gas phase flow effect of the liquid phase redistribution device 210.

[0069] In order to improve the uniformity of phosphoric acid spraying, in some embodiments, the spray head 222 is preferably arranged at the center position of the cross section of the tower cavity, and the spray port faces downward.

[0070] In some embodiments, the second defluorination structure further comprises a first liquid level interlocking system; the first liquid level interlocking system is used to control the liquid flow in the spray assembly 220, so as to prevent the liquid phase in the liquid phase redistribution tank 213 from overflowing, or to prevent the liquid pressurizing pump 221 from running empty. The first liquid level interlocking system can be various, such as: a flow regulating valve arranged on the pipeline of the spray assembly 220, or a flow controller in communication connection with the liquid pressurizing pump 221.

[0071] In some embodiments, the first liquid level interlock system comprises a first liquid level monitor and a first liquid level controller; the first liquid level monitor is disposed in the liquid redistribution tank 213 for monitoring the liquid level in the liquid redistribution tank 213; the first liquid level controller is communicatively connected with the first liquid level monitor and the liquid pressurization pump 221, respectively; the first liquid level controller has a pre-set liquid level monitoring range; when the first liquid level monitor detects that the liquid level in the liquid redistribution tank 213 exceeds the pre-set upper limit of the liquid level, the first liquid level controller sends a signal to the liquid pressurization pump 221 to increase the output power of the liquid pressurization pump 221 to increase the liquid flow rate in the spray assembly 220, so as to reduce the liquid level in the liquid redistribution tank 213 to within the liquid level monitoring range; when the first liquid level monitor detects that the liquid level in the liquid redistribution tank 213 is lower than the pre-set lower limit of the liquid level, the first liquid level controller sends a signal to the liquid pressurization pump 221 to decrease the output power of the liquid pressurization pump 221 to decrease the liquid flow rate in the spray assembly 220, so as to increase the liquid level in the liquid redistribution tank 213 to within the liquid level monitoring range. Generally, the pre-set upper limit of the liquid level is not higher than the height of the gas phase cylinder 212, so as to ensure that the liquid does not overflow the gas phase cylinder 212; for example, when the height of the gas phase cylinder 212 is 300 mm, the pre-set upper limit of the liquid level is 200 mm. The pre-set lower limit of the liquid level is not lower than the liquid outlet of the liquid redistribution tank 213, so as to prevent the liquid pressurization pump 221 from running empty.

[0072] In combination with Figure 1 and Figure 3 or in combination with Figure 3 and Figure 5As shown, in some embodiments, the liquid inlet mechanism comprises a liquid phase distributor 310 and a tower body liquid inlet 320; the liquid phase distributor 310 comprises at least two annular tubes 311 with different diameters and arranged concentrically, and a central tube 312 in communication with each annular tube 311 respectively; the lower edge of each annular tube 311 is provided with at least two uniformly distributed liquid outlet holes 313, and the smaller the diameter of the annular tube 311, the smaller the diameter of the liquid outlet hole 313 formed thereon; the liquid outlet holes 313 on each annular tube 311 together form the liquid outlet part of the liquid inlet mechanism; the tower body liquid inlet 320 is arranged on the side of the tower body 100, and the liquid inlet of the liquid phase distributor 310 is connected with the tower body liquid inlet 320. The liquid inlet mechanism can uniformly and dispersedly send the phosphoric acid to be defluorinated into the tower cavity through the liquid phase distributor 310, so as to increase the mass transfer interface; the liquid phase distributor 310 is usually made of corrosion-resistant material, and the main body is preferably made of stainless steel and the outer lining is preferably made of polytetrafluoroethylene; the stainless steel used to make the main body of the liquid phase distributor 310 is preferably one of 316L, 2205 and 904 stainless steel. Considering that the larger the diameter of the annular tube 311, the larger the capacity, and the phosphoric acid is generally supplied from the inside to the outside through the central tube 312, so that the smaller the diameter of the annular tube 311, the smaller the diameter of the liquid outlet hole 313 formed thereon, so as to ensure that the liquid outlet hole 313 of the annular tube 311 with a larger diameter also has phosphoric acid flowing out, and the flowing-out phosphoric acid is more uniformly distributed. In order to ensure the liquid outlet effect, the diameter of the liquid outlet hole 313 is preferably 1-10 mm.

[0073] In order to improve the flow rate and stability of the liquid supply, again as shown Figure 3 As shown, in some embodiments, the central tube 312 is a "cross" shaped pipe, which comprises two connection tubes arranged in cross and in communication with each other, both of which are in communication with each annular tube 311, and a central liquid inlet is formed at the intersection part of the two connection tubes, which is the liquid inlet of the liquid phase distributor 310.

[0074] Again as shown Figure 3 As shown, in some embodiments, the annular tube 311 is three, which are inner ring tube, middle ring tube and outer ring tube respectively; the diameter of the liquid outlet hole 313 formed on the inner ring tube is 1-3 mm, the diameter of the liquid outlet hole 313 formed on the middle ring tube is 4-6 mm, and the diameter of the liquid outlet hole 313 formed on the outer ring tube is 7-10 mm, so as to further improve the uniformity of the phosphoric acid liquid inlet. Preferably, the diameter of the liquid outlet hole 313 formed on the inner ring tube is 2 mm, the diameter of the liquid outlet hole 313 formed on the middle ring tube is 4 mm, and the diameter of the liquid outlet hole 313 formed on the outer ring tube is 7 mm.

[0075] In combination with Figure 1 and Figure 4 As shown, or in combination with Figure 4 and Figure 5As shown, in some embodiments, the air inlet mechanism comprises a tower body air inlet 610 and a gas phase distributor 620; the tower body air inlet 610 is arranged at the side of the tower body 100; the gas phase distributor 620 comprises an air inlet main pipe 621 arranged in the air inlet cavity section and connected with the tower body air inlet 610, and an air inlet branch pipe 622 arranged on the air inlet main pipe 621 and in communication with the air inlet main pipe 621; the upper edge of the air inlet branch pipe 622 is provided with at least two uniformly distributed air outlet holes 623, and each air outlet hole 623 together constitutes an air outlet part of the air inlet mechanism. The air inlet mechanism can uniformly and dispersedly deliver the gas phase such as hot air or superheated steam into the air inlet cavity section of the tower cavity through the gas phase distributor 620, so as to increase the mass transfer interface; the gas phase distributor 620 is usually made of corrosion-resistant material, and the main body is preferably made of stainless steel and the outer lining is preferably made of polytetrafluoroethylene; the stainless steel used to make the main body of the gas phase distributor 620 is preferably 2205 or 904 stainless steel. In order to ensure the dispersion of the air outlet, the diameter of the air outlet hole 623 is preferably 1-2 mm.

[0076] For example, the air inlet branch pipe 622 is arranged in the axial direction of the air inlet main pipe 621. Figure 4 As shown, in some embodiments, the air inlet main pipe 621 is arranged in the radial direction of the tower body 100; the air inlet branch pipe 622 is at least two and is arranged in the axial direction of the air inlet main pipe 621; the air inlet branch pipe 622 is perpendicular to the air inlet main pipe 621, and the length of the air inlet branch pipe 622 closer to the central axis of the tower body 100 is longer. In this way, each air inlet branch pipe 622 can be adapted to the width of different positions of the cross section of the tower cavity, further improving the uniformity of the air outlet.

[0077] For example, the air inlet branch pipe 622 is arranged in the axial direction of the air inlet main pipe 621. Figure 4 As shown, in some embodiments, the air inlet branch pipe 622 is seven and is symmetrically distributed.

[0078] In some embodiments, the device further comprises a second liquid level interlocking system, which comprises a second liquid level monitor, a liquid discharge pump 710, a second liquid level controller; the second liquid level monitor is arranged in the gas inlet cavity section to monitor the liquid level height in the gas inlet cavity section; the liquid discharge pump 710 is arranged outside the tower body 100, and its liquid inlet is connected to the tower body liquid outlet 102 through the discharge pipeline 720; the second liquid level controller is communicatively connected with the second liquid level monitor and the liquid discharge pump 710; the second liquid level controller can control the liquid discharge pump 710 to increase or decrease the output power when the second liquid level monitor detects that the liquid level in the gas inlet cavity section is not within the set discharge height range. For example, the set discharge height range is 200-300 mm above the gas inlet mechanism, when the second liquid level monitor detects that the liquid level height in the gas inlet cavity section is lower than 200 mm above the gas inlet mechanism, it sends a signal to the liquid discharge pump 710 to reduce the output power, controls the liquid discharge pump 710 to reduce the output power to reduce the discharge flow, until the liquid level in the gas inlet cavity section returns to the set discharge height range; when the second liquid level monitor detects that the liquid level height in the gas inlet cavity section is higher than 300 mm above the gas inlet mechanism, it sends a signal to the liquid discharge pump 710 to increase the output power, controls the liquid discharge pump 710 to increase the output power to increase the discharge flow, until the liquid level in the gas inlet cavity section returns to the set discharge height range. The liquid discharge pump 710 is mainly used to transport the defluorinated phosphoric acid product out of the tower body 100; the liquid discharge pump 710 can be multiple, preferably a frequency-adjustable centrifugal pump, and the main material thereof is preferably full graphite or stainless steel lined polytetrafluoroethylene, and further preferably 304 or 316L stainless steel as the base material.

[0079] For example Figure 1 As shown, the first defluorination structure is a filler defluorination structure 400 arranged in the defluorination cavity section. The filler defluorination structure 400 is mainly composed of fillers, which can be ceramic fillers, plastic fillers, metal fillers, etc., and is preferably a polytetrafluoroethylene filler piece. Compared with the existing bubble column tower, this embodiment uses the filler defluorination structure 400 as the first defluorination structure, which can disperse the gas-liquid two-phase flow by using fillers, and the fillers have a large specific surface area, which can provide a larger mass transfer interface, increase the contact area and contact time of phosphoric acid and gas phase, make the fluorine impurities better transferred to the gas phase and removed, and facilitate to improve the defluorination efficiency.

[0080] For example Figure 5As shown, the first defluorination structure is a plate type defluorination structure, which includes at least two layers of second trays 510 arranged in an up-down interval in the defluorination cavity section, and a cofferdam 520 is arranged on the upper surface of the second tray 510, which separates the area on the upper side of the second tray 510 into a defluorination zone 511 and an overflow zone 512; a gas phase redistribution device 530 is arranged on the second tray 510 corresponding to the defluorination zone 511, and the gas phase redistribution device 530 has a gas phase redistribution inlet 531 communicating with the defluorination cavity section on the lower side of the second tray 510 and a gas phase redistribution outlet hole 532 communicating with the defluorination zone 511; any two adjacent layers of second trays 510, the overflow zone 512 of the upper second tray 510 is communicated with the defluorination zone 511 of the lower second tray 510 through a downcomer 540; the overflow zone 512 of the lowermost second tray 510 is communicated with the liquid phase redistribution tank 213 through the downcomer 540.

[0081] Among them, the second tray 510 is generally arranged in the defluorination cavity section, preferably the second tray 510 is transversely arranged in the defluorination cavity section; the material of the second tray 510 is preferably stainless steel lined with polytetrafluoroethylene, and further preferably 304 or 316L stainless steel as the base material; generally, a circular hole with a diameter of 15-30 mm is formed on the second tray 510, and the gas phase redistribution device 530 is installed at the circular hole. The cofferdam 520 is generally arranged close to the inner wall of the tower body 100, so that the volume of the defluorination zone 511 is greater than that of the overflow zone 512; the height of the cofferdam 520 can be determined according to the amount of phosphoric acid treated per unit time, the volume of the separated defluorination zone 511, and other factors, and is preferably 120-150 mm. A plurality of gas phase redistribution outlet holes 532 are generally formed on the gas phase redistribution device 530, which are used to make the gas phase enter the phosphoric acid in the defluorination zone in the form of smaller bubbles, and provide a larger mass transfer interface; the number and size of the gas phase redistribution device 530 can be set as needed; the gas phase redistribution device 530 can be made of various materials, and is preferably made of polytetrafluoroethylene; on the same second tray 510, the upper end of the gas phase redistribution device 530 is generally lower than the upper end of the cofferdam 520, and at least the gas phase redistribution outlet hole 532 on the gas phase redistribution device 530 should be lower than the upper end of the cofferdam 520, so as to ensure that the gas phase can fully mass transfer with the liquid phase phosphoric acid flowing through the defluorination zone 511 after being blown out from the gas phase redistribution outlet hole 532. The downcomer 540 is mainly used to transfer the phosphoric acid in the plate type defluorination structure from the upper layer to the lower layer, and the downcomer 540 is generally made of corrosion-resistant materials, preferably made of polytetrafluoroethylene or stainless steel lined with polytetrafluoroethylene, and further preferably 304 or 316L stainless steel as the base material.

[0082] In order to further improve the uniformity of gas phase dispersion, combined with Figure 5 and Figure 6As shown in the drawings, in some embodiments, at least two regularly distributed gas phase redistributors 530 are arranged on the second tray 510. The gas phase redistributors 530 can be regularly distributed on the second tray 510 in various ways, such as: equidistantly distributed side by side, arranged in a straight line, arranged in a triangle, arranged in a circular array, and the like; the triangle arrangement refers to multiple rows of gas phase redistributors 530 arranged side by side, and any two adjacent rows of gas phase redistributors 530 are staggered with each other, as shown in the drawings. Figure 6 As shown in the drawings.

[0083] In combination with Figure 5 and Figure 7 As shown in the drawings, in some embodiments, the gas phase redistributor 530 is a cylindrical cover with a closed upper end and an open lower end, and at least two uniformly distributed gas phase redistribution gas outlets 532 are arranged on the side wall of the cylindrical cover. Preferably, the height of the gas phase redistributor 530 is 50-80 mm, and the diameter of the gas phase redistribution gas outlet 532 is 1-2 mm; the gas phase redistributor 530 with such a size structure has good aeration effect, can ensure that the gas phase enters the phosphoric acid in the defluorination zone in the form of smaller bubbles, and can provide a larger mass transfer interface and more uniform dispersion.

[0084] In combination with Figure 5 , Figure 6 and Figure 7 As shown in the drawings, in some embodiments, a plurality of regularly distributed circular holes are arranged on the second tray 510, the diameter of the circular hole is preferably 15-30 mm, the distance between the adjacent two circular holes is preferably 0.75-1.5 times the diameter, and the arrangement of the plurality of circular holes is preferably a straight line arrangement or a triangle arrangement; the gas phase redistributor 530 has a connecting part matched with the circular hole, and is connected with the circular hole through the connecting part.

[0085] The device for deep defluorination of phosphoric acid provided by the utility model can realize gas phase dispersion through the filler defluorination structure 400 or the plurality of uniformly distributed gas phase redistribution gas outlets 532, can greatly strengthen mass transfer, can greatly shorten the mass transfer distance in the gas phase, can reduce the gas consumption required by the device for defluorination, can obtain a high-concentration fluorine-containing gas phase after defluorination, is beneficial to subsequent recovery, and can also reduce production cost; the spray assembly 220 at the lower part of the tower cavity can disperse high-viscosity phosphoric acid in the gas phase, can greatly reduce the mass transfer resistance of fluorine impurities in the phosphoric acid, and can realize deep defluorination of the phosphoric acid.

[0086] The description of the various embodiments of the present application presented herein is presented for the purpose of illustration only and not intended to detail or limit the disclosed embodiments. Many modifications and variations to the described embodiments will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application, or technical improvement over the prior art, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

[0087] In this document, various embodiments of the present application can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the present application. Accordingly, the description of a range should be considered to have specifically disclosed all possible subranges as well as individual numerical values within that range. For example, a description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6, This applies regardless of the breadth of the range.

[0088] It should be understood that certain features of the present application described in the context of separate embodiments can also be provided in combination in a single embodiment. Conversely, various features of the present application described in the context of a single embodiment can also be provided separately or in any appropriate

[0089] All publications, patents, and patent applications mentioned herein are hereby incorporated by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. Further, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present application. To the extent that section headings are used, they should not be construed as necessarily limiting.

Claims

1. A device for deep defluorination of phosphoric acid, comprising a tower body (100), a liquid inlet mechanism, a first defluorination structure and a gas inlet mechanism; The inner cavity of the tower body (100) is a tower cavity, which is sequentially divided into a liquid inlet cavity section, a defluorination cavity section and a gas inlet cavity section from top to bottom; the top of the tower body (100) is provided with a tower body gas outlet (101) communicating with the tower cavity, and the bottom of the tower body (100) is provided with a tower body liquid outlet (102) communicating with the tower cavity; The liquid inlet mechanism is arranged on the tower body (100), and the liquid outlet part thereof is located in the liquid inlet cavity section; The first defluorination structure is a packed defluorination structure (400) or a plate-type defluorination structure, which is arranged in the defluorination cavity section; The gas inlet mechanism is arranged on the tower body (100), and the gas outlet part thereof is located in the gas inlet cavity section; characterized in that Further comprising a second defluorination structure, which comprises a liquid phase redistributor (210) and a spraying assembly (220); The liquid phase redistributor (210) comprises a first tower plate (211) arranged in the defluorination cavity section and located below the first defluorination structure, and a gas phase cylinder (212) arranged on the first tower plate (211); the defluorination cavity section between the upper end of the gas phase cylinder (212) and the upper surface of the first tower plate (211) forms a liquid phase redistribution groove (213); the cylinder cavity of the gas phase cylinder (212) is a gas phase passage, which communicates the defluorination cavity sections on both sides of the first tower plate (211); The spraying assembly (220) comprises a liquid pressurizing pump (221) arranged outside the tower body (100), a spraying head (222) arranged in the defluorination cavity section and located below the first tower plate (211), a liquid inlet pipe (223) connecting the liquid inlet of the liquid pressurizing pump (221) with the liquid phase redistribution groove (213), and a liquid outlet pipe (224) connecting the liquid outlet of the liquid pressurizing pump (221) with the liquid inlet of the spraying head (222).

2. The apparatus for deep defluorination of phosphoric acid according to claim 1, characterized by: The second defluorination structure further comprises a first liquid level interlocking system, which comprises a first liquid level monitor and a first liquid level controller; The first liquid level monitor is arranged in the liquid phase redistribution groove (213) and used for monitoring the liquid level height in the liquid phase redistribution groove (213); The first liquid level controller is communicatively connected with the first liquid level monitor and the liquid pressurizing pump (221); the first liquid level controller can control the liquid pressurizing pump (221) to increase the output power to increase the liquid flow in the spraying assembly (220) when the first liquid level monitor detects that the liquid level in the liquid phase redistribution groove (213) exceeds the set upper limit of the liquid level; the first liquid level controller can also control the liquid pressurizing pump (221) to reduce the output power to reduce the liquid flow in the spraying assembly (220) when the first liquid level monitor detects that the liquid level in the liquid phase redistribution groove (213) is lower than the set lower limit of the liquid level.

3. The apparatus for deep defluorination of phosphoric acid according to claim 1, characterized by: The liquid inlet mechanism comprises a liquid phase distributor (310) and a tower body liquid inlet (320). The liquid phase distributor (310) comprises at least two annular pipes (311) with different diameters and arranged concentrically, and a central pipe (312) communicating with each annular pipe (311) respectively; The lower edge of the annular pipe (311) is provided with at least two uniformly distributed liquid outlet holes (313), and the annular pipe (311) with a smaller diameter is provided with a smaller liquid outlet hole (313); The liquid inlet of the liquid phase distributor (310) is connected with the liquid inlet of the tower body (320).

4. The apparatus for deep defluorination of phosphoric acid according to claim 3, characterized by: The central pipe (312) is a "cross" pipe comprising two intersecting and communicating connecting pipes, both of which communicate with each annular pipe (311), and the intersection of the two connecting pipes is provided with a central liquid inlet, which is the liquid inlet of the liquid phase distributor (310).

5. The apparatus for deep defluorination of phosphoric acid according to claim 1, characterized by: The gas inlet mechanism comprises a tower body gas inlet (610) and a gas phase distributor (620); The tower body gas inlet (610) is arranged on the side of the tower body (100); The gas phase distributor (620) comprises a gas inlet main pipe (621) arranged in the gas inlet cavity section and connected with the tower body gas inlet (610), and a gas inlet branch pipe (622) arranged on the gas inlet main pipe (621) and communicating therewith; The upper edge of the gas inlet branch pipe (622) is provided with at least two uniformly distributed gas outlet holes (623), and each gas outlet hole (623) together constitutes the gas outlet part of the gas inlet mechanism.

6. The apparatus for deep defluorination of phosphoric acid according to claim 5, characterized by: The gas inlet main pipe (621) is arranged along the radial direction of the tower body (100); The gas inlet branch pipe (622) is at least two, and is arranged in the axial direction of the gas inlet main pipe (621) at intervals; the gas inlet branch pipe (622) is perpendicular to the gas inlet main pipe (621), and the gas inlet branch pipe (622) closer to the central axis of the tower body (100) is longer.

7. The apparatus for deep defluorination of phosphoric acid according to claim 5, characterized by: It also comprises a second liquid level interlocking system, which comprises a second liquid level monitor, a liquid discharge pump (710), and a second liquid level controller; The second liquid level monitor is arranged in the gas inlet cavity section for monitoring the liquid level height in the gas inlet cavity section; The liquid discharge pump (710) is arranged outside the tower body (100), and its liquid inlet is connected with the tower body liquid outlet (102) through a discharge pipeline (720); The second liquid level controller is in communication connection with the second liquid level monitor and the liquid discharge pump (710) respectively; when the second liquid level monitor detects that the liquid level in the gas inlet cavity section is not within the set discharge height range, the second liquid level controller can control the liquid discharge pump (710) to increase or decrease the output power.

8. The apparatus for deep defluorination of phosphoric acid according to any one of claims 1 to 7, characterized in that: The plate type defluorination structure comprises at least two layers of second tower plates (510) arranged in the defluorination cavity section at intervals, and the upper surface of the second tower plate (510) is provided with a cofferdam (520), which divides the area on the upper side of the second tower plate (510) into a defluorination zone (511) and an overflow zone (512); A gas phase redistribution device (530) is arranged on the second tray (510) corresponding to the defluorination zone (511), and has a gas phase redistribution inlet (531) communicating with the defluorination cavity section on the lower side of the second tray (510) and a gas phase redistribution outlet hole (532) communicating with the defluorination zone (511); Any two adjacent second trays (510) are communicated by downcomers (540) between the overflow zone (512) of the upper second tray (510) and the defluorination zone (511) of the lower second tray (510); the overflow zone (512) of the lowermost second tray (510) is communicated with the liquid phase redistribution groove (213) by a downcomer (540).

9. The apparatus for deep defluorination of phosphoric acid according to claim 8, characterized by: The first tray (211) is provided with at least two regularly distributed gas phase cylinders (212); The second tray (510) is provided with at least two regularly distributed gas phase redistribution devices (530).

10. The apparatus for deep defluorination of phosphoric acid according to claim 9, characterized by: The gas phase redistribution device (530) is a cylindrical cover with a closed upper end and an open lower end, and at least two uniformly distributed gas phase redistribution outlet holes (532) are arranged on the side wall of the cylindrical cover.

Images