Electrolytic apparatus and process for producing nitrogen trifluoride gas

Abstract

The application belongs to the technical field of electrolytic equipment and electrolytic process, and particularly relates to an electrolytic equipment and process method for producing nitrogen trifluoride gas. The electrolytic equipment for producing nitrogen trifluoride gas comprises an electrolytic tank body, which is divided into a cathode chamber and an anode chamber by a baffle; a cathode plate is arranged in the electrolytic tank body; a cathode connecting post, an anode gas outlet and a cathode gas outlet are arranged on the electrolytic tank body; a cathode rod is connected to the cathode connecting post; an anode connecting post is arranged on the electrolytic tank body and connected to an anode plate; the cathode plate comprises blades arranged in a 'wiFi' signal shape from bottom to top; the blades are arc-shaped; and the blades are provided with cathode plate air holes. The electrolytic equipment for producing nitrogen trifluoride gas provided by the application replaces the traditional plate-shaped and louver-shaped cathode plate with a wiFi-shaped cathode plate, increases the effective use area of the electrode, improves the electronic conversion efficiency and reduces the production cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrolytic equipment and electrolytic process, and particularly relates to an electrolytic equipment and process method for producing nitrogen trifluoride gas. BACKGROUND

[0002] Currently, the production of nitrogen trifluoride by electrolysis mainly electrolyzes ammonium bifluoride to generate a reaction of nitrogen trifluoride and hydrogen gas, and the reaction principle equation of nitrogen trifluoride is as follows:

[0003] Anode: 6F - + 6e→ 3F2, 3F2+ 2NH4 + → 2NF3 + 4H2+ 2e - ,

[0004] Cathode: 6H++ 6e→ 3H2,

[0005] Total reaction equation: NH4HF2+ HF→ NF3+ 3H2.

[0006] In the traditional electrolytic cell, the cathode plate is a uniformly plate-shaped or louvered plate, and the following problems exist: (1) The concentration of electrolyte in the upper part and the bottom part of the electrolytic cell is different, resulting in uneven current density of the anode plate, the current density of the lower part is greater than that of the upper part, the lower half of the anode plate corrodes faster, resulting in a greatly reduced utilization rate of the anode plate. (2) Hydrogen gas is generated at the cathode, and the hydrogen gas rises on both sides of the cathode plate. When the generated gas speed is too fast, the gas will diffuse to both sides, and diffuse into the anode chamber to mix with the nitrogen trifluoride, resulting in a decrease in the purity of the nitrogen trifluoride product, an increase in the purification cost, and a decrease in the product quality.

[0007] CN206308424U discloses an electrolytic cell for preparing nitrogen trifluoride, which comprises a cell body, a cell cover, a skirt plate, an anode gas chamber, a cathode gas chamber, an anode plate, a cathode plate, a cooling coil, an anode terminal post and a cathode terminal post. The anode plate is fixed on the anode terminal post by bolts, and flow guide holes are provided on the anode plate. The flow guide holes are multiple, and the number of flow guide holes decreases from one end of the anode plate close to the anode terminal post to the other end. The thickness of the anode plate at the one end close to the anode terminal post is thinner than that at the other end. Flow guide holes are also provided on the cathode plate. The problem of too fast electrochemical corrosion of the anode plate during the electrolytic production of nitrogen trifluoride is solved, and the anode plate after corrosion presents a thick upper and thin lower state, causing waste.

[0008] CN209906896U discloses an electrolytic cell for preparing nitrogen trifluoride gas, which comprises a tank cover and a tank body; the tank body comprises an anode chamber, a cathode chamber and an electrolytic cell; the anode chamber and the cathode chamber are completely separated by a baffle and are connected by a salt bridge, the electrolytic cell is diagonally provided with a nitrogen gas pipeline, and the electrolytic cell is in communication with the cathode chamber and the anode chamber; the tank cover comprises an anode gas outlet, an anode rod, a baffle, a salt bridge, an anode nitrogen inlet, a cathode gas outlet, a cathode nitrogen inlet and a cathode rod. SUMMARY

[0009] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art, and to provide an electrolytic device for producing nitrogen trifluoride gas, which replaces the traditional plate and louver with a WiFi shape, increases the effective use area of the electrode, improves the electronic conversion efficiency, and reduces the production cost.

[0010] The electrolytic device for producing nitrogen trifluoride gas comprises an electrolytic cell body, which is divided into a cathode chamber and an anode chamber by a baffle; a cathode plate is arranged inside the electrolytic cell body, a cathode terminal post, an anode gas outlet and a cathode gas outlet are arranged on the electrolytic cell body, a cathode rod is connected to the cathode terminal post, an anode terminal post is arranged on the electrolytic cell body, and an anode plate is connected to the anode terminal post; the cathode plate comprises blades arranged in a "WiFi" signal shape from bottom to top, the blades are arc-shaped, and a cathode plate air hole is arranged on the blades.

[0011] The cathode plate comprises a support flat steel, an end plate and a terminal post mounting identification hole.

[0012] The blades are blade 7, blade 6, blade 5, blade 4, blade 3, blade 2 and blade 1 from bottom to top, and each blade is in a semicircular shape, and the diameter of the complete circle determines the area of the blade.

[0013] The outer diameter of the arc-shaped blade 1 is 42-48 mm; the outer diameter of the arc-shaped blade 3 and blade 2 is 35-41 mm; the outer diameter of the arc-shaped blade 5 and blade 4 is 30-34 mm; and the outer diameter of the arc-shaped blade 7 and blade 6 is 23-28 mm.

[0014] The blade comprises a steel pipe two and a steel pipe one.

[0015] The steel pipe one is a circular pipe with an outer diameter of 15-20 mm; and the steel pipe two is a circular pipe with an outer diameter of 8-13 mm.

[0016] The distance a between each blade is 27-32 mm.

[0017] The electrolytic device for producing nitrogen trifluoride gas produces nitrogen trifluoride gas by the following steps:

[0018] (1) feeding: feeding the mixed electrolyte of ammonium hydrogen fluoride and hydrogen fluoride into the electrolytic cell body, closing the valve to seal the system, then nitrogen replacement, the nitrogen scanning amount is 2000-2500ml / min, and the replacement lasts for 8-12min;

[0019] (2) electrolysis: connecting the positive pole of the power supply to the anode terminal and connecting the negative pole of the power supply to the cathode terminal to perform electrolysis, the anode product nitrogen trifluoride is generated from the anode plate and collected from the anode gas outlet through the anode chamber, the cathode product hydrogen is generated from the anode plate and discharged from the anode gas outlet through the cathode chamber, and the anode chamber and the cathode chamber are separated by a baffle.

[0020] The mass ratio of ammonium hydrogen fluoride and hydrogen fluoride in step (1) is (3:1)-(3:1.2).

[0021] The electrolysis current is maintained at 2240-2250A.

[0022] After the electrolytic cell body is sealed as a whole, the electrolyte in the electrolytic cell body is the mixed electrolyte of ammonium hydrogen fluoride and hydrogen fluoride, the mass ratio of ammonium hydrogen fluoride and hydrogen fluoride is 3:1, nitrogen is filled in the interior, then the electrolysis stage is performed, the positive pole of the power supply is connected to the anode terminal, the negative pole of the power supply is connected to the cathode terminal, in order to prevent short circuit, the cathode terminal and the anode terminal are both insulated by insulating rubber, and the electrolytic cell body is also insulated, after all checks are completed, power-on is performed, the current is maintained, electrolysis is performed, hydrogen gas is generated at the cathode and discharged from the cathode gas outlet through the cathode chamber, and nitrogen trifluoride is generated at the anode and discharged from the anode gas outlet through the anode chamber.

[0023] Compared with the prior art, the present application has the beneficial effects that:

[0024] (1) the electrolytic equipment of the present application is adopted, the cathode plate is arranged in a WiFi type, and there is a gas permeable hole in the middle, the area gradually increases from bottom to top, when the cathode gas is generated, it will not diffuse to both sides into the anode chamber to mix with the nitrogen trifluoride gas, so that the purity of nitrogen trifluoride is greatly improved, and the gas generated by the traditional cathode plate will diffuse to the anode chamber due to gas fluctuation, reducing the purity of nitrogen trifluoride.

[0025] (2) the shape and arrangement of the cathode plate of the electrolytic equipment of the present application increase the electrolysis area, compared with the traditional cathode plate, the same effective area, the width of the cathode plate of the present application is greatly shortened, and the use amount of the cathode plate is reduced.

[0026] (3) the cathode plate of the electrolytic equipment adopts the design of smaller and smaller area from top to bottom, which makes the damage degree of the anode plate averaged, and prolongs the service life of the anode plate. In the normal electrolysis process, the current density is large at the bottom of the electrolytic cell, the existing design of the cathode plate causes large loss of the anode plate, which leads to small damage degree of the upper part of the anode plate and large damage degree of the lower part of the anode plate, and further leads to that the anode plate cannot work normally, reduces the production efficiency and increases the cost. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a front structure schematic diagram of the electrolytic equipment of the application;

[0028] Figure 2 It is a side structure schematic diagram of the electrolytic equipment of the application;

[0029] Figure 3 It is a front structure schematic diagram of the cathode plate;

[0030] Figure 4 It is a side structure schematic diagram of the cathode plate;

[0031] In the figure: 1, cathode chamber; 2, anode chamber; 3, cathode plate; 31, blade; 311, blade 1; 312, blade 2, 313, blade 3; 314, blade 4; 315, blade 5; 316, blade 6; 317, blade 7; 318, steel pipe one; 319, steel pipe two; 32, support flat steel; 33, end plate; 34, cathode plate air hole; 35, terminal post installation mark hole; 4, cathode terminal post; 5, anode gas outlet; 6, cathode gas outlet; 7, cathode rod; 8, baffle; 9, anode plate; 91, upper part of anode plate; 92, lower part of anode plate; 10, anode terminal post. DETAILED DESCRIPTION

[0032] The application will be further described below in combination with specific embodiments.

[0033] As shown in Figure 1 and Figure 2 , the electrolytic equipment for producing nitrogen trifluoride gas of the application: comprising an electrolytic cell body, the electrolytic cell body is divided into a cathode chamber 1 and an anode chamber 2 by a baffle 8; the electrolytic cell body is internally provided with a cathode plate 3, the electrolytic cell body is provided with a cathode terminal post 4, an anode gas outlet 5, a cathode gas outlet 6, the cathode terminal post 4 is connected with a cathode rod 7, the electrolytic cell body is provided with an anode terminal post 10, the anode terminal post 10 is connected with an anode plate 9; the cathode plate 3 comprises blades 31, the blades 31 are arranged in a “WiFi” signal shape from bottom to top, the blades 31 are arc-shaped, and the blades 31 are provided with cathode plate air holes 34.

[0034] As shown in Figure 3As shown, the cathode plate 3 comprises a support flat steel 32, an end plate 33, and a terminal post mounting mark hole 35.

[0035] As shown, the blades 31 are sequentially blade 7 317, blade 6 316, blade 5 315, blade 4 314, blade 3 313, blade 2 312, and blade 1 311 from bottom to top, each blade adopts a semicircular structure. Figure 4

[0036] The arc-shaped outer diameter of the blade 1 311 is 45mm; the arc-shaped outer diameter of the blade 3 313 and the blade 2 312 is 38mm; the arc-shaped outer diameter of the blade 5 315 and the blade 4 314 is 32mm; and the arc-shaped outer diameter of the blade 7 317 and the blade 6 316 is 25mm.

[0037] The blade 31 comprises a steel pipe two 319 and a steel pipe one 318.

[0038] The steel pipe one 318 is a circular pipe with an outer diameter of 18mm; and the steel pipe two 319 is a circular pipe with an outer diameter of 10mm.

[0039] The distance a between each blade of the blade 3 313 is 31mm.

[0040] Embodiment 1

[0041] The electrolytic apparatus is used to carry out the process method for producing nitrogen trifluoride gas by electrolytic apparatus, which comprises the following steps:

[0042] (1) Feeding: the mixed electrolyte with a mass ratio of ammonium hydrogen fluoride to hydrogen fluoride of 3:1 is fed into the electrolytic cell body, the valve is closed to seal the system, then nitrogen replacement is carried out, the nitrogen sweeping amount is 2500ml / min, and the replacement lasts for 10min;

[0043] (2) Electrolysis: the positive pole of the power supply is connected to the anode terminal post, and the negative pole of the power supply is connected to the cathode terminal post, then power electrolysis is carried out, the electrolysis current is maintained at 2250A, the anode product nitrogen trifluoride is produced from the anode plate, is collected through the anode chamber from the anode gas outlet, the cathode product hydrogen is produced from the anode plate, is discharged through the cathode chamber from the anode gas outlet, and the anode chamber and the cathode chamber are separated by a baffle.

[0044] Embodiment 2

[0045] The electrolytic apparatus is used to carry out the process method for producing nitrogen trifluoride gas by electrolytic apparatus, which comprises the following steps:

[0046] ​(1) Feeding: the mixed electrolyte with the mass ratio of ammonium bifluoride to hydrogen fluoride of 3:1 is fed into the electrolytic tank body, the valve is closed to seal the system, then nitrogen replacement is carried out, the nitrogen sweeping amount is 2000ml / min, and the replacement lasts for 8min;

[0047] (2) Electrolysis: the positive pole of the power supply is connected to the anode terminal, and the negative pole of the power supply is connected to the cathode terminal, then power electrolysis is carried out, the electrolysis current is maintained at 2240A, the anode product nitrogen trifluoride is produced from the anode plate, is collected through the anode chamber from the anode gas outlet, the cathode product hydrogen is produced from the anode plate, is discharged through the cathode chamber from the anode gas outlet, and the anode chamber and the cathode chamber are separated by a baffle.

[0048] Example 3

[0049] The electrolytic equipment for producing nitrogen trifluoride gas is used to carry out the process method for producing nitrogen trifluoride gas, which comprises the following steps:

[0050] (1) Feeding: the mixed electrolyte with the mass ratio of ammonium bifluoride to hydrogen fluoride of 3:1 is fed into the electrolytic tank body, the valve is closed to seal the system, then nitrogen replacement is carried out, the nitrogen sweeping amount is 2500ml / min, and the replacement lasts for 12min;

[0051] (2) Electrolysis: the positive pole of the power supply is connected to the anode terminal, and the negative pole of the power supply is connected to the cathode terminal, then power electrolysis is carried out, the electrolysis current is maintained at 2245A, the anode product nitrogen trifluoride is produced from the anode plate, is collected through the anode chamber from the anode gas outlet, the cathode product hydrogen is produced from the anode plate, is discharged through the cathode chamber from the anode gas outlet, and the anode chamber and the cathode chamber are separated by a baffle.

[0052] Comparative Example 1

[0053] The electrolytic tank with the traditional cathode plate is used, the cathode plate is a conventional existing straight plate type cathode plate, the cathode current area and the temperature thereof are ensured to be the same as those of Example 3, and the process method for producing nitrogen trifluoride gas is completely the same as that of Example 3.

[0054] The electrolysis parameters, electrolysis quality and purity of nitrogen trifluoride of Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0055] Table 1 Comparison of Examples 1-3 and Comparative Example

[0056]

[0057] As shown in Table 1, the purity of nitrogen trifluoride is obviously improved to more than 90% by using the electrolytic tank with the "WiFi" arranged semicircular arc cathode plate, and the purity is improved by 20% compared with the traditional electrolytic tank.

[0058] The anode plate of the electrolytic cell is corroded by the above examples and the comparative examples, and the anode plate in the examples and the comparative examples is the existing anode plate, such as Figure 2 As shown in the figure, the anode plate 9 is divided into the upper part 91 and the lower part 92 of the anode plate by the middle boundary line, and the thickness and the electrolysis time before and after electrolysis are shown in Table 2.

[0059] Table 2 Corrosion of the anode plate

[0060]

[0061] As can be seen from the above Table 2, the electrolytic cell with the cathode plate arranged in the "WiFi" arrangement and the circular arc shape according to the present application has a more uniform corrosion degree of the anode plate than the conventional electrolytic cell, and the anode plate with a thickness less than 0.3 cm will not work efficiently, so the electrolytic cell according to the present application has a longer service life of the anode plate.

[0062] Of course, the above content is only the preferred embodiment of the present application, and cannot be considered as limiting the scope of the embodiments of the present application. The present application is also not limited to the above examples, and the equivalent changes and improvements made by those skilled in the art within the essential scope of the present application should be attributed to the patent coverage of the present application.

Claims

1. An electrolytic device for producing nitrogen trifluoride gas, characterized in that: The electrolytic cell body is divided into a cathode chamber (1) and an anode chamber (2) by a baffle (8). A cathode plate (3) is provided inside the electrolytic cell body. A cathode terminal (4), an anode gas outlet (5), and a cathode gas outlet (6) are provided on the electrolytic cell body. A cathode rod (7) is connected to the cathode terminal (4). An anode terminal (10) is provided on the electrolytic cell body. An anode plate (9) is connected to the anode terminal (10). The cathode plate (3) includes blades (31). The blades (31) are arranged from bottom to top in the shape of a "wiFi" signal. The blades (31) are arc-shaped. A cathode plate vent hole (34) is provided on the blades (31). The blades (31) from bottom to top are blade 7 (317), blade 6 (316), blade 5 (315), blade 4 (314), blade 3 (313), blade 2 (312), and blade 1 (311). The outer diameter of the arc-shaped blade 1 (311) is 42-48 mm; the outer diameter of the arc-shaped blades 3 (313) and 2 (312) is 35-41 mm; the outer diameter of the arc-shaped blades 5 (315) and 4 (314) is 30-34 mm; and the outer diameter of the arc-shaped blades 7 (317) and 6 (316) is 23-28 mm.

2. The electrolytic equipment for producing nitrogen trifluoride gas according to claim 1, characterized in that: The cathode plate (3) includes a supporting flat steel (32), an end plate (33), and a terminal block mounting mark hole (35).

3. The electrolytic equipment for producing nitrogen trifluoride gas according to claim 1, characterized in that: The blade (31) comprises steel pipe two (319) and steel pipe one (318).

4. The electrolytic equipment for producing nitrogen trifluoride gas according to claim 1, characterized in that: Steel pipe one (318) is a round tube with an outer diameter of 15-20 mm; steel pipe two (319) is a round tube with an outer diameter of 8-13 mm.

5. The electrolytic equipment for producing nitrogen trifluoride gas according to claim 1, characterized in that: The distance a between the individual blades of the blade (31) is 27-32 mm.

6. A process for producing nitrogen trifluoride gas using the electrolytic equipment for producing nitrogen trifluoride gas according to any one of claims 1-5, characterized in that: Includes the following steps: (1) Feeding: Add ammonium bifluoride and hydrogen fluoride mixed electrolyte to the electrolytic cell body, close the valve, and then perform nitrogen purging. The nitrogen purging rate is 2000~2500 ml / min, and the purging continues for 8-12 min. (2) Electrolysis: Connect the positive terminal of the power supply to the anode terminal and the negative terminal of the power supply to the cathode terminal to carry out electrolysis. The anode product, nitrogen trifluoride, is produced from the anode plate and collected from the anode gas outlet through the anode chamber. The cathode product, hydrogen, is produced from the anode plate and discharged from the anode gas outlet through the cathode chamber. The anode chamber and the cathode chamber are separated by a baffle.

7. The process method for producing nitrogen trifluoride gas using an electrolytic equipment according to claim 6, characterized in that: The mass ratio of ammonium bifluoride to hydrogen fluoride in step (1) is (3:1) - (3:1.2).

8. The process method for producing nitrogen trifluoride gas using the electrolytic equipment according to claim 6, characterized in that: The electrolysis current is maintained at 2240-2250A.

Images