Equipment and method for removing potassium chlorate in electrolytic light salt brine by formaldehyde catalytic reduction method

Abstract

The invention relates to the technical field of electrolytic product treatment, discloses equipment and a method for removing potassium chlorate in electrolytic light salt brine by a formaldehyde catalytic reduction method, and solves the problem of poor removal effect on the electrolytic product potassium chlorate in the prior art. The device comprises a reactor, a mixer, an electrolysis waste brine main pipeline, a plurality of electrolysis waste brine branch pipelines, a hydrochloric acid supply pipe, a formaldehyde supply pipe and a brine discharge pipe, the reactor is connected with the mixer, and the mixer, the hydrochloric acid supply pipe and the formaldehyde supply pipe are all connected with the electrolysis waste brine branch pipelines. The electrolytic waste brine branch pipeline is connected with the electrolytic tank through the electrolytic waste brine main pipeline, the electrolytic waste brine branch pipeline and the electrolytic tank are both connected with the refined brine supply pipe, the brine discharge pipe is connected between the reactor and the electrolytic tank, and the reactor is composed of a shell, a controller, a servo motor, a center supporting sleeve and a mixing and stirring mechanism; by means of the equipment, potassium chlorate in electrolysis products can be efficiently removed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrolysis product treatment, and specifically relates to a device and method for removing potassium chlorate in electrolytic dilute brine by a formaldehyde catalytic reduction method. BACKGROUND

[0002] Electrolysis of potassium chloride to produce caustic soda and chlorine is one of the important processes in the chemical industry. During the electrolysis process, potassium chlorate is inevitably produced as a byproduct and dissolves in the dilute brine. Potassium chlorate has strong oxidizing properties and poses potential hazards to subsequent equipment and process flow.

[0003] 1. Potassium chlorate is a strong oxidizing agent and may react with other substances in the system, especially when the temperature rises or organic matter is encountered, posing a risk of explosion or fire;

[0004] 2. Potassium chlorate has high solubility and may accumulate in the brine circulation system, causing changes in the physical and chemical properties of the brine, such as changes in electrical conductivity and pH, which in turn affect the electrolysis efficiency and product quality;

[0005] 3. Potassium chlorate may also corrode equipment, especially under high temperature or acidic conditions, which may accelerate the corrosion of metal parts and shorten the service life of the equipment;

[0006] Therefore, the application proposes a method for removing potassium chlorate in electrolytic sodium chloride dilute brine using formaldehyde. By adding formaldehyde to the dilute brine, formaldehyde reacts with potassium chlorate to produce harmless potassium chloride and carbon dioxide, thereby effectively removing potassium chlorate. SUMMARY

[0007] To overcome the defects of the prior art, the application provides a device and method for removing potassium chlorate in electrolytic dilute brine by a formaldehyde catalytic reduction method, effectively solving the problem of poor removal of electrolysis products potassium chlorate.

[0008] To achieve the above purpose, the application provides the following technical solution: a device for removing potassium chlorate in electrolytic dilute brine by a formaldehyde catalytic reduction method, comprising a reactor, a mixer, an electrolytic waste brine main pipeline, a plurality of electrolytic waste brine branch pipelines, a hydrochloric acid supply pipe, a formaldehyde supply pipe, and a brine discharge pipe. The reactor is connected to the mixer, the mixer, the hydrochloric acid supply pipe, and the formaldehyde supply pipe are all connected to the electrolytic waste brine branch pipelines, the electrolytic waste brine branch pipelines are connected to the electrolytic cell through the electrolytic waste brine main pipeline, the electrolytic waste brine branch pipelines and the electrolytic cell are both connected to the refined brine supply pipe, and the brine discharge pipe is connected between the reactor and the electrolytic cell.

[0009] The reactor is composed of a shell, a controller, a servo motor, a central support sleeve and a mixing stirring mechanism, the controller is fixedly connected to the front surface of the shell, the servo motor is fixedly connected to the middle position of the top end of the shell, the central support sleeve is fixedly connected to the central position inside the shell, and the mixing stirring mechanism is connected to the inner and outer surfaces of the central support sleeve and fixedly connected with the output shaft of the servo motor.

[0010] The mixing stirring mechanism is composed of a rotating drum one, a plurality of strip-shaped neodymium magnets one, a rotating sleeve one, a plurality of iron bars one, a plurality of long support arms, a plurality of stirring blades one, a rotating drum two, a plurality of strip-shaped neodymium magnets two, a rotating sleeve two, a plurality of iron bars two, a plurality of short support arms, a plurality of stirring blades two and a reversing assembly, the rotating drum one and the rotating drum two are respectively rotatably connected to the top end and the bottom end inside the central support sleeve, the rotating drum one is fixedly connected with the output shaft of the servo motor, the reversing assembly is connected between the rotating drum one, the rotating drum two and the central support sleeve, the strip-shaped neodymium magnets one are fixedly connected to the outer surface of the rotating drum one, the strip-shaped neodymium magnets two are fixedly connected to the outer surface of the rotating drum two, the rotating sleeve one is rotatably connected to the top end of the outer surface of the central support sleeve, the iron bars one are embeddedly arranged inside the rotating sleeve one, the stirring blades one are connected to the outer surface of the rotating sleeve one through the long support arms, the rotating sleeve two is rotatably connected to the bottom end of the outer surface of the central support sleeve, the iron bars two are embeddedly arranged inside the rotating sleeve two, and the stirring blades two are fixedly connected to the outer surface of the rotating sleeve two through the short support arms.

[0011] Preferably, the top of the reactor and the electrolytic cell is provided with a gas-liquid separator and a chlorine washing tower, the gas-liquid separator is connected with the reactor and the electrolytic cell through pipelines respectively, and the chlorine washing tower is connected with the gas-liquid separator through a pipeline.

[0012] Preferably, the electrolytic waste brine branch pipeline, the hydrochloric acid supply pipeline, the formaldehyde supply pipeline and the refined brine supply pipeline are all provided with electromagnetic valves and flow valves.

[0013] Preferably, the top end of the shell is provided with a cover plate, the inside of the shell is provided with a water heating sandwich, the bottom end of one side of the shell is fixedly provided with a hot water inlet pipe in communication with the water heating sandwich, and the top end of the other side of the shell is fixedly provided with a drain pipe in communication with the water heating sandwich.

[0014] Preferably, the shell, the central support sleeve, the rotating sleeve one, the long support arms, the stirring blades one, the rotating sleeve two, the short support arms and the stirring blades two are all made of FRP material.

[0015] Preferably, the rotating sleeve one and the rotating sleeve two are rotatably connected with the central support sleeve through a plurality of ceramic bearings.

[0016] Preferably, the inside of the central support sleeve is fixedly provided with a plurality of positioning plates matched with the rotating drum one and the rotating drum two, and the positioning plates are connected with the rotating drum one and the rotating drum two through bearings.

[0017] Preferably, the reversing assembly is composed of bevel gear one, bevel gear two, support seat and bevel gear three, the bevel gear one is fixedly connected to the bottom end of the rotating drum one, the bevel gear two is fixedly connected to the top end of the rotating drum two, the support seat is fixedly connected to the middle position of the inner side of the central support sleeve, and the bevel gear three is rotatably connected to one end of the support seat and is engaged with the bevel gear one and the bevel gear two respectively.

[0018] Preferably, the mixer is composed of premixing sleeve, U-shaped support arm, booster pump, temporary storage pool, L-shaped flow guide pipe, a plurality of self-rotating stirring paddles one and a plurality of self-rotating stirring paddles two, the U-shaped support arm is fixedly connected to the inside of the premixing sleeve, the self-rotating stirring paddles one and the self-rotating stirring paddles two are rotatably connected with the U-shaped support arm, the self-rotating stirring paddles one and the self-rotating stirring paddles two are alternately arranged, the booster pump is connected to one end of the premixing sleeve, the booster pump is connected with the temporary storage pool through the L-shaped flow guide pipe, and the temporary storage pool is connected with the electrolytic waste brine branch pipeline.

[0019] Preferably, the catalytic reduction method of the equipment for removing potassium chlorate in electrolytic fresh brine by the formaldehyde catalytic reduction method comprises the following steps:

[0020] Step one, the fresh brine containing ClO3 - is led out from the inside of the electrolytic cell through the electrolytic waste brine main pipeline, part of the refined brine is led out through the refined brine supply pipe, and is discharged to the electrolytic waste brine branch pipeline at the same time, and then is discharged to the mixer through the electrolytic waste brine branch pipeline;

[0021] Step two, hydrochloric acid (HCL) and formaldehyde (CH2O) are added to the inside of the electrolytic waste brine branch pipeline, and the flow is controlled according to the proportion, and the pH is adjusted to 1.0-1.5;

[0022] Step three, the mixed solution is discharged to the inside of the mixer to realize premixing and improve the mixing uniformity;

[0023] Step four, the premixed solution is discharged to the inside of the reactor, the temperature in the reactor is controlled to be 60-70 DEG C, and is fully mixed and uniformly mixed through the mixing and stirring mechanism, so that the formaldehyde is reacted under the acidic condition, the reducing property of the formaldehyde under the acidic condition reduces ClO3 - to harmless Cl - , CO2 and H2O are generated at the same time, the reaction time is controlled to be 60-90 minutes, and the reaction equation is 3HCHO+2KClO3→2KCl+3CO2↑+3H2O;

[0024] Step five, the waste gas generated in the reaction enters the gas-liquid separator and the chlorine gas washing tower to realize recycling.

[0025] Compared with the prior art, the beneficial effects of the present application are:

[0026] (1), in the work, by adding hydrochloric acid, to ensure that formaldehyde in acidic conditions to carry out the reaction, ClO3 - reduced to harmless Cl - , CO2 and H2O, can reduce the concentration of potassium chlorate in the brine to 0.1g / L below, far lower than the removal effect of the existing method;

[0027] (2), by formaldehyde catalytic reduction method to remove potassium chlorate in electrolytic brine, the reaction temperature and time are in the acceptable range of industrial production, without high temperature and high pressure equipment, reduce the equipment cost and energy consumption, the reaction of potassium chloride and carbon dioxide are harmless substances, will not cause secondary pollution to the environment, formaldehyde is cheap, and no need to add other expensive reagents in the reaction process, reduce the processing cost;

[0028] (3), by setting by the premix sleeve, U type support arm, booster pump, temporary storage pool, L type flow guide pipe, a number of self rotating stirring paddle and a number of self rotating stirring paddle two constitute a mixer, can realize the pre-mixing of hydrochloric acid, formaldehyde and salt water, improve the mixing uniformity;

[0029] (4), by setting the shell, controller, servo motor, center support sleeve, and setting by the rotating drum, a number of bar-shaped neodymium magnets, rotating sleeve, a number of iron bars, a number of long support arms, a number of stirring blades, rotating drum two, a number of bar-shaped neodymium magnets, rotating sleeve two, a number of iron bars, a number of short support arms, a number of stirring blades two and reversing assembly constitute a mixing and stirring mechanism, can realize auxiliary stirring in the reaction process, can improve the uniformity of stirring, further improve the fullness of the reaction;

[0030] (5), by setting the shell, center support sleeve, rotating sleeve one, long support arm, stirring blade one, rotating sleeve two, short support arm, stirring blade two are FRP material, can improve the corrosion resistance, and then improve the service life and stability. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, together with the embodiments of the application, to explain the application, and do not constitute a limitation on the application.

[0032] In the drawings:

[0033] Figure 1 Flow chart for removing potassium chlorate in electrolytic brine by formaldehyde catalytic reduction method of the application;

[0034] Figure 2 Schematic diagram of the reactor structure of the application;

[0035] Figure 3 Cross-sectional view of the reactor of the application;

[0036] Figure 4 Schematic diagram of the internal structure of the reactor of the present invention;

[0037] Figure 5 Schematic diagram of the structure of the mixing and stirring mechanism of the present invention;

[0038] Figure 6 For the present invention Figure 5 A partial enlarged view of point A in the middle;

[0039] Figure 7 Schematic diagram of the structure of the mixer of the present invention;

[0040] In the figure: 1. Reactor; 2. Mixer; 3. Electrolysis waste brine main pipeline; 4. Electrolysis waste brine branch pipeline; 5. Hydrochloric acid supply pipe; 6. Formaldehyde supply pipe; 7. Brine discharge pipe; 8. Electrolytic cell; 9. Refined brine supply pipe; 10. Gas-liquid separator; 11. Chlorine scrubber; 12. Solenoid valve; 13. Flow valve; 14. Housing; 15. Controller; 16. Servo motor; 17. Center support sleeve; 18. Mixing and stirring mechanism; 19. Rotating drum (1); 20. Neodymium bar magnet (1); 21. Rotating sleeve (1); 22. Iron bar (1); 23. Long support arm; 24. Stirring blade (1) ; 25. Rotating drum 2; 26. Bar neodymium magnet 2; 27. Rotating sleeve 2; 28. Iron bar 2; 29. ​​Short support arm; 30. Stirring blade 2; 31. Reversing assembly; 32. Cover plate; 33. Water heating interlayer; 34. Hot water inlet pipe; 35. Drain pipe; 36. Ceramic bearing; 37. Positioning plate; 38. Helical gear 1; 39. Helical gear 2; 40. Support seat; 41. Helical gear 3; 42. Premixing sleeve; 43. U-shaped support arm; 44. Booster pump; 45. Temporary storage tank; 46. L-shaped guide pipe; 47. Self-rotating stirring paddle 1; 48. Self-rotating stirring paddle 2. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0042] Example, by Figures 1 to 7The application discloses a device for removing potassium chlorate in electrolytic dilute brine by a formaldehyde catalytic reduction method, which comprises a reactor 1, a mixer 2, an electrolytic waste brine main pipeline 3, a plurality of electrolytic waste brine branch pipelines 4, a hydrochloric acid supply pipeline 5, a formaldehyde supply pipeline 6, a brine discharge pipeline 7, the reactor 1 is connected with the mixer 2, the mixer 2, the hydrochloric acid supply pipeline 5 and the formaldehyde supply pipeline 6 are connected with the electrolytic waste brine branch pipelines 4, the electrolytic waste brine branch pipelines 4 are connected with an electrolytic cell 8 through the electrolytic waste brine main pipeline 3, the electrolytic waste brine branch pipelines 4 and the electrolytic cell 8 are connected with a refined brine supply pipeline 9, and the brine discharge pipeline 7 is connected between the reactor 1 and the electrolytic cell 8.

[0043] The electrolytic dilute brine is discharged into the mixer 2 and the reactor 1 through the electrolytic waste brine main pipeline 3 and the electrolytic waste brine branch pipelines 4, hydrochloric acid and formaldehyde are added through the hydrochloric acid supply pipeline 5 and the formaldehyde supply pipeline 6, a certain amount of refined brine is added through the refined brine supply pipeline 9, pre-mixing is realized through the mixer 2, reaction is realized through the reactor 1, and the reacted brine is discharged into the electrolytic cell 8 to realize secondary electrolysis.

[0044] The reactor 1 is composed of a shell 14, a controller 15, a servo motor 16, a central support sleeve 17 and a mixing and stirring mechanism 18, the controller 15 is fixedly connected to the front face of the shell 14, the servo motor 16 is fixedly connected to the middle position of the top end of the shell 14, the central support sleeve 17 is fixedly connected to the central position in the interior of the shell 14, the mixing and stirring mechanism 18 is connected to the inner and outer surfaces of the central support sleeve 17 and is fixedly connected with the output shaft of the servo motor 16, and the mixing and stirring mechanism 18 is composed of a rotating drum 1 9, a plurality of strip-shaped neodymium magnets 1 0, a rotating sleeve 1 21, a plurality of iron bars 1 22, a plurality of long support arms 23, a plurality of stirring blades 1 24, a rotating drum 2 5, a plurality of strip-shaped neodymium magnets 2 6, a rotating sleeve 2 27, a plurality of iron bars 2 28, a plurality of short support arms 29, a plurality of stirring blades 3 0 and a reversing assembly 3 1, the rotating drum 1 9 and the rotating drum 2 5 are rotationally connected to the top end and the bottom end in the interior of the central support sleeve 1 7 respectively, the rotating drum 1 9 is fixedly connected with the output shaft of the servo motor 1 6, the reversing assembly 3 1 is connected between the rotating drum 1 9, the rotating drum 2 5 and the central support sleeve 1 7, the strip-shaped neodymium magnets 1 0 are fixedly connected to the outer surface of the rotating drum 1 9, the strip-shaped neodymium magnets 2 6 are fixedly connected to the outer surface of the rotating drum 2 5, the rotating sleeve 1 21 is rotationally connected to the top end of the outer surface of the central support sleeve 1 7, the iron bars 1 22 are embeddedly arranged in the interior of the rotating sleeve 1 21, the stirring blades 1 24 are connected to the outer surface of the rotating sleeve 1 21 through the long support arms 23, the rotating sleeve 2 27 is rotationally connected to the bottom end of the outer surface of the central support sleeve 1 7, the iron bars 2 28 are embeddedly arranged in the interior of the rotating sleeve 2 27, and the stirring blades 3 0 are fixedly connected to the outer surface of the rotating sleeve 2 27 through the short support arms 29.

[0045] When the reactor 1 is operating, the servo motor 16 drives the first rotor 19 to rotate. The first rotor 19 drives the second rotor 25 to rotate via the reversing assembly 31. The second rotor 25 rotates in the opposite direction to the first rotor 19. The bar-shaped neodymium magnet 120 on the first rotor 19 produces a magnetic attraction effect on the iron bar 12, thereby driving the first rotating sleeve 21 to rotate. The first rotating sleeve 21 drives the long support arm 23 and the stirring blade 1 24 to rotate. The bar-shaped neodymium magnet 26 on the second rotor 25 produces a magnetic attraction effect on the iron bar 28, thereby driving the second rotating sleeve 27 to rotate. The second rotating sleeve 27 drives the short support arm 29 and the stirring blade 2 30 to rotate. The iron bars 1 22 and 28 are embedded in each other to avoid corrosion.

[0046] like Figure 4 As shown, when the drum 19 drives the long support arm 23 and the stirring blade 1 24 to rotate counterclockwise, the drum 25 drives the short support arm 29 and the stirring blade 2 30 to rotate clockwise. When the stirring blade 2 30 rotates, it drives the bottom solution to circulate clockwise, and at the same time generates an upward thrust on the solution, so that the solution circulates meridionally and moves upward along the axial direction. When the stirring blade 1 24 rotates, it drives the top solution to circulate counterclockwise, and at the same time generates a downward thrust on the solution, so that the solution circulates meridionally and moves downward along the axial direction. Since the stirring blade 1 24 and the stirring blade 2 30 have different extension lengths, an axial circulation is formed. Through the clockwise and counterclockwise meridional circulation of the solution and the formation of multi-channel axial circulation, the solution is fully mixed and the comprehensiveness of the reaction is improved.

[0047] A gas-liquid separator 10 and a chlorine scrubber 11 are provided on the top of the reactor 1 and the electrolytic cell 8. The gas-liquid separator 10 is connected to the reactor 1 and the electrolytic cell 8 respectively through pipelines, and the chlorine scrubber 11 is connected to the gas-liquid separator 10 through pipelines, so as to process and recycle the waste gas.

[0048] Electrolytic waste brine branch pipe 4, hydrochloric acid supply pipe 5, formaldehyde supply pipe 6, and refined brine supply pipe 9 are all provided with a solenoid valve 12 and a flow valve 13, which can control the discharge volume and thus achieve pre-mixing;

[0049] A cover plate 32 is provided at the top of the housing 14, and a water heating interlayer 33 is provided inside the housing 14. A hot water inlet pipe 34 connected to the water heating interlayer 33 is fixedly provided at the bottom end of one side of the housing 14, and a drain pipe 35 connected to the water heating interlayer 33 is fixedly provided at the top end of the other side of the housing 14, thereby achieving water heating and improving heating comprehensiveness.

[0050] The shell 14, the central support sleeve 17, the rotating sleeve 1 21, the long support arm 23, the stirring blade 1 24, the rotating sleeve 2 27, the short support arm 29, and the stirring blade 2 30 are all made of FRP, which can improve the corrosion resistance.

[0051] The rotating sleeve one 21 and the rotating sleeve two 27 are rotatably connected with the center support sleeve 17 through a plurality of ceramic bearings 36, which can improve the stability and activity of the rotating sleeve one 21 and the rotating sleeve two 27, and the ceramic bearings 36 can have corrosion resistance;

[0052] The inside of the center support sleeve 17 is fixedly provided with a plurality of positioning plates 37 matched with the rotating drum one 19 and the rotating drum two 25, the positioning plates 37 are connected with the rotating drum one 19 and the rotating drum two 25 through bearings, which can realize auxiliary positioning of the rotating drum one 19 and the rotating drum two 25 and improve the stability thereof;

[0053] The reversing assembly 31 is composed of a bevel gear one 38, a bevel gear two 39, a support seat 40 and a bevel gear three 41, the bevel gear one 38 is fixedly connected to the bottom end of the rotating drum one 19, the bevel gear two 39 is fixedly connected to the top end of the rotating drum two 25, the support seat 40 is fixedly connected to the middle position of one side inside the center support sleeve 17, and the bevel gear three 41 is rotatably connected to one end of the support seat 40 and meshes with the bevel gear one 38 and the bevel gear two 39 respectively, which can realize reversing driving and make the rotating drum one 19 and the rotating drum two 25 rotate in opposite directions;

[0054] The mixer 2 is composed of a premixing sleeve 42, a U-shaped support arm 43, a booster pump 44, a temporary storage pool 45, an L-shaped flow guide pipe 46, a plurality of self-rotating stirring paddles one 47 and a plurality of self-rotating stirring paddles two 48, the U-shaped support arm 43 is fixedly connected to the inside of the premixing sleeve 42, the self-rotating stirring paddles one 47 and the self-rotating stirring paddles two 48 are rotatably connected with the U-shaped support arm 43, the self-rotating stirring paddles one 47 and the self-rotating stirring paddles two 48 are alternately arranged, the booster pump 44 is connected to one end of the premixing sleeve 42, the booster pump 44 is connected with the temporary storage pool 45 through the L-shaped flow guide pipe 46, and the temporary storage pool 45 is connected with the electrolytic waste brine branch pipeline 4;

[0055] The mixed solution enters the temporary storage pool 45 for temporary storage, and then is accelerated to the inside of the premixing sleeve 42 through the booster pump 44, the self-rotating stirring paddles one 47 and the self-rotating stirring paddles two 48 rotate under the impact of the fluid, which realizes the auxiliary stirring effect and rotates in opposite directions, thereby improving the mixing uniformity;

[0056] The catalytic reduction method of the equipment for removing potassium chlorate in electrolytic dilute brine by formaldehyde catalytic reduction method includes the following steps:

[0057] Step one, the dilute brine containing ClO3 - from the inside of the electrolytic cell 8 through the electrolytic waste brine main pipeline 3, and part of the refined brine is introduced through the refined brine supply pipe 9 and is simultaneously discharged to the electrolytic waste brine branch pipeline 4, and then is discharged to the mixer 2 through the electrolytic waste brine branch pipeline 4;

[0058] Step two, add hydrochloric acid (HCL) and formaldehyde (CH2O) into the electrolytic waste brine branch pipeline 4, and control the flow according to the proportion, adjust the pH to 1.0-1.5;

[0059] Step three, the mixed solution is discharged into the mixer 2 to realize pre-mixing and improve the mixing uniformity;

[0060] Step four, the pre-mixed solution is discharged into the reactor 1, the temperature inside the reactor 1 is controlled at 60-70℃, and the mixing and stirring mechanism is used for fully mixing and uniformity, to ensure that formaldehyde reacts under acidic conditions, the reducing property of formaldehyde under acidic conditions, ClO3 - is reduced to harmless Cl - , CO2 and H2O are generated at the same time, the reaction time is controlled at 60-90 minutes, and the reaction equation is: 3HCHO+2KClO3→2KCl+3CO2↑+3H2O;

[0061] Step five, the waste gas generated by the reaction enters the gas-liquid separator 10 and the chlorine washing tower 11 to realize recycling;

[0062] Experimental data:

[0063] Experiment one: in the potassium chlorate concentration of 1g / L of brine, add formaldehyde solution (concentration is 30%), the molar ratio of formaldehyde to potassium chlorate is 1.2:1, the reaction temperature is 25℃, the reaction time is 1.5 hours, after the reaction, the concentration of potassium chlorate is reduced to 0.08g / L, and the yield of potassium chloride is 98%;

[0064] Experiment two: in the potassium chlorate concentration of 2g / L of brine, add formaldehyde solution (concentration is 50%), the molar ratio of formaldehyde to potassium chlorate is 1.5:1, the reaction temperature is 35℃, the reaction time is 2 hours, after the reaction, the concentration of potassium chlorate is reduced to 0.05g / L, and the yield of potassium chloride is 99%.

[0065] In work, by adding hydrochloric acid, to ensure that formaldehyde reacts under acidic conditions, ClO3 - is reduced to harmless Cl -The potassium chlorate in the electrolytic brine is removed by the formaldehyde catalytic reduction method, the reaction temperature and time are in the acceptable range of industrial production, high temperature and high pressure equipment is not needed, the equipment cost and energy consumption are reduced, the generated potassium chloride and carbon dioxide are harmless substances, no secondary pollution to the environment is caused, the price of formaldehyde is low, no other expensive reagent needs to be added in the reaction process, and the treatment cost is reduced; the mixer composed of the premixing sleeve, the U-shaped support arm, the booster pump, the temporary storage pool, the L-shaped flow guide pipe, the plurality of self-rotating stirring paddles one and the plurality of self-rotating stirring paddles two is arranged, so that the hydrochloric acid, the formaldehyde and the brine can be premixed, and the mixing uniformity is improved; the mixing and stirring mechanism is arranged in the shell, the controller, the servo motor, the center support sleeve, the rotating sleeve one, the plurality of strip-shaped neodymium magnets one, the plurality of iron bars one, the plurality of long support arms, the plurality of stirring blades one, the rotating sleeve two, the plurality of strip-shaped neodymium magnets two, the plurality of iron bars two, the plurality of short support arms, the plurality of stirring blades two and the reversing assembly, so that the auxiliary stirring can be realized in the reaction process, the stirring uniformity can be improved, and the reaction sufficiency is further improved; the shell, the center support sleeve, the rotating sleeve one, the long support arm, the stirring blade one, the rotating sleeve two, the short support arm and the stirring blade two are made of FRP material, so that the corrosion resistance is improved, and the service life and the stability are improved.

Claims

1. A device for removing potassium chlorate from electrolytic brine by a formaldehyde catalytic reduction method, comprising a reactor (1), a mixer (2), a main electrolytic brine waste pipe (3), a plurality of electrolytic brine waste pipes (4), a hydrochloric acid supply pipe (5), a formaldehyde supply pipe (6) and a brine discharge pipe (7), characterized in that: The reactor (1) is connected to the mixer (2); the mixer (2), the hydrochloric acid supply pipe (5), and the formaldehyde supply pipe (6) are all connected to the electrolysis waste brine branch pipe (4); the electrolysis waste brine branch pipe (4) is connected to the electrolysis cell (8) through the electrolysis waste brine main pipe (3); the electrolysis waste brine branch pipe (4) and the electrolysis cell (8) are both connected to the refined brine supply pipe (9); and the brine discharge pipe (7) is connected between the reactor (1) and the electrolysis cell (8); The reactor (1) is composed of a shell (14), a controller (15), a servo motor (16), a central support sleeve (17) and a mixing and stirring mechanism (18). The controller (15) is fixedly connected to the front of the shell (14), the servo motor (16) is fixedly connected to the middle position of the top of the shell (14), the central support sleeve (17) is fixedly connected to the center position inside the shell (14), and the mixing and stirring mechanism (18) is connected to the inner and outer surfaces of the central support sleeve (17) and is fixedly connected to the output shaft of the servo motor (16). The mixing and stirring mechanism (18) is composed of a rotating drum (19), a plurality of bar-shaped neodymium magnets (20), a rotating sleeve (21), a plurality of iron bars (22), a plurality of long support arms (23), a plurality of stirring blades (24), a rotating drum (25), a plurality of bar-shaped neodymium magnets (26), a rotating sleeve (27), a plurality of iron bars (28), a plurality of short support arms (29), a plurality of stirring blades (30) and a reversing assembly (31). The rotating drum (19) and the rotating drum (25) are respectively rotatably connected to the top and bottom ends of the center support sleeve (17). The rotating drum (19) is fixedly connected to the output shaft of the servo motor (16). The reversing assembly (31) is connected to the rotating drum (19), the rotating drum (25) and the center support sleeve (17). Between the support sleeves (17), the bar neodymium magnet 1 (20) is fixedly connected to the outer surface of the rotating drum 1 (19), the bar neodymium magnet 2 (26) is fixedly connected to the outer surface of the rotating drum 2 (25), the rotating sleeve 1 (21) is rotatably connected to the top of the outer surface of the central support sleeve (17), the iron bar 1 (22) is embedded in the interior of the rotating sleeve 1 (21), the stirring blade 1 (24) is connected to the outer surface of the rotating sleeve 1 (21) through the long support arm (23), the rotating sleeve 2 (27) is rotatably connected to the bottom end of the outer surface of the central support sleeve (17), the iron bar 2 (28) is embedded in the interior of the rotating sleeve 2 (27), and the stirring blade 2 (30) is fixedly connected to the outer surface of the rotating sleeve 2 (27) through the short support arm (29).

2. The device for removing potassium chlorate from electrolytic brine by formaldehyde catalytic reduction method according to claim 1, characterized in that: A gas-liquid separator (10) and a chlorine scrubber (11) are provided on the top of the reactor (1) and the electrolytic cell (8); the gas-liquid separator (10) is connected to the reactor (1) and the electrolytic cell (8) respectively through pipelines, and the chlorine scrubber (11) is connected to the gas-liquid separator (10) through pipelines.

3. The device for removing potassium chlorate from electrolytic brine by formaldehyde catalytic reduction method according to claim 1, characterized in that: The electrolysis waste brine branch pipe (4), the hydrochloric acid supply pipe (5), the formaldehyde supply pipe (6), and the refined brine supply pipe (9) are all provided with a solenoid valve (12) and a flow valve (13).

4. The device for removing potassium chlorate from electrolytic brine by formaldehyde catalytic reduction method according to claim 1, characterized in that: The top end of the shell (14) is provided with a cover plate (32), a water heating interlayer (33) is provided inside the shell (14), a hot water inlet pipe (34) communicating with the water heating interlayer (33) is fixedly provided at the bottom end of one side of the shell (14), and a drain pipe (35) communicating with the water heating interlayer (33) is fixedly provided at the top end of the other side of the shell (14).

5. The device for removing potassium chlorate from electrolytic brine by formaldehyde catalytic reduction method according to claim 1, characterized in that: The shell (14), the central support sleeve (17), the first rotating sleeve (21), the long support arm (23), the first stirring blade (24), the second rotating sleeve (27), the short support arm (29), and the second stirring blade (30) are all made of FRP material.

6. The device for removing potassium chlorate from electrolytic brine by formaldehyde catalytic reduction method according to claim 1, characterized in that: The rotating sleeve 1 (21) and the rotating sleeve 2 (27) are both rotatably connected to the central support sleeve (17) through a plurality of ceramic bearings (36).

7. The device for removing potassium chlorate from electrolytic brine by formaldehyde catalytic reduction method according to claim 1, characterized in that: A plurality of positioning plates (37) matching the first rotating drum (19) and the second rotating drum (25) are fixedly provided inside the central support sleeve (17), and the positioning plates (37) are connected to the first rotating drum (19) and the second rotating drum (25) through bearings.

8. The device for removing potassium chlorate from electrolytic brine by formaldehyde catalytic reduction method according to claim 1, characterized in that: The reversing assembly (31) is composed of a bevel gear 1 (38), a bevel gear 2 (39), a support seat (40) and a bevel gear 3 (41). The bevel gear 1 (38) is fixedly connected to the bottom end of the rotating drum 1 (19), the bevel gear 2 (39) is fixedly connected to the top end of the rotating drum 2 (25), the support seat (40) is fixedly connected to the middle position of one side inside the central support sleeve (17), and the bevel gear 3 (41) is rotatably connected to one end of the support seat (40) and meshes with the bevel gear 1 (38) and the bevel gear 2 (39) respectively.

9. The device for removing potassium chlorate from electrolytic brine by formaldehyde catalytic reduction method according to claim 1, characterized in that: The mixer (2) is composed of a premixing sleeve (42), a U-shaped support arm (43), a booster pump (44), a temporary storage tank (45), an L-shaped guide tube (46), a plurality of self-rotating stirring paddles (47) and a plurality of self-rotating stirring paddles (48). The U-shaped support arm (43) is fixedly connected to the interior of the premixing sleeve (42). The self-rotating stirring paddles (47) and the self-rotating stirring paddles (48) are both rotatably connected to the U-shaped support arm (43). The self-rotating stirring paddles (47) and the self-rotating stirring paddles (48) are alternately arranged. The booster pump (44) is connected to one end of the premixing sleeve (42). The booster pump (44) is connected to the temporary storage tank (45) through the L-shaped guide tube (46). The temporary storage tank (45) is connected to the electrolysis waste brine branch pipeline (4).

10. The catalytic reduction method for removing potassium chlorate from electrolyzed brine by the formaldehyde catalytic reduction method according to claims 1-9, characterized in that: The following steps are involved: Step 1: Lead out the ClO3 from the electrolytic cell (8) through the electrolysis waste brine main pipeline (3) - At the same time, part of the refined brine is drawn out through the refined brine supply pipe (9) and discharged to the electrolysis waste brine branch pipe (4), and then discharged to the mixer (2) through the electrolysis waste brine branch pipe (4); Step 2: Add hydrochloric acid (HCL) and formaldehyde (CH2O) into the electrolysis waste brine branch pipe (4), control the flow rate according to the ratio, and adjust the pH to 1.0-1.5; Step 3: The mixed solution is discharged into the mixer (2) to achieve pre-mixing and improve mixing uniformity; Step 4: The pre-mixed solution is discharged into the reactor (1), and the internal temperature of the reactor (1) is controlled at 60-70°C. The solution is fully mixed by a mixing and stirring mechanism to ensure that the formaldehyde reacts under acidic conditions. The reducing property of formaldehyde under acidic conditions can reduce ClO3 - Reduced to harmless Cl - , CO2 and H2O are generated at the same time, the reaction time is controlled at 60-90 minutes, and the reaction equation is: 3HCHO+2KClO3→2KCl+3CO2↑+3H2O; Step 5: The waste gas generated by the reaction enters the gas-liquid separator (10) and the chlorine scrubber (11) for recycling.

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