阅读说明：本技术 一种制氟电解槽液态氟化氢集中供料方法 (Centralized feeding method for liquid hydrogen fluoride in fluorine-making electrolytic cell ) 是由 张凯 魏刚 马智刚 王来喜 苏冉 赵兴科 于 2021-07-08 设计创作，主要内容包括：本发明涉及电解制氟领域,公开了一种制氟电解槽液态氟化氢集中供料方法,所述方法包括以下步骤：(1)检验供料装置的气密性；(2)计算电解槽内氟化氢加料量；(3)电解槽加料操作准备；(4)电解质取样分析；取样分析目标电解槽电解质酸度值,记录电解槽的电子秤示值；(5)电解槽液态氟化氢加料操作；打开液态氟化氢加料阀门,液态氟化氢贮存容器内的氟化氢在压力作用下,通过液态氟化氢供料管道与液态氟化氢加料管,加入电解槽内,当电子秤示值增加到一定值时,关闭液态氟化氢加料阀门。本发明有效解决了制氟电解槽中液态氟化氢供料操作程序烦琐,安全风险较大的问题,具有操作简单,成本低的优点。(The invention relates to the field of electrolytic fluorine preparation, and discloses a centralized feeding method of liquid hydrogen fluoride in a fluorine preparation electrolytic cell, which comprises the following steps: (1) checking the air tightness of the feeding device; (2) calculating the hydrogen fluoride feeding amount in the electrolytic cell; (3) preparing an electrolytic bath feeding operation; (4) sampling and analyzing electrolyte; sampling and analyzing the electrolytic hyaluronic acid value of the target electrolytic cell, and recording the electronic scale indicating value of the electrolytic cell; (5) feeding liquid hydrogen fluoride into the electrolytic cell; open liquid hydrogen fluoride charging valve, hydrogen fluoride in the liquid hydrogen fluoride storage container under the pressure effect through liquid hydrogen fluoride feed pipeline and liquid hydrogen fluoride filling tube, add the electrolysis trough in, when the electronic scale indicating value increases to a definite value, close liquid hydrogen fluoride charging valve. The invention effectively solves the problems of complicated feeding operation procedure and larger safety risk of the liquid hydrogen fluoride in the fluorine-making electrolytic cell, and has the advantages of simple operation and low cost.)

1. A centralized feeding method of liquid hydrogen fluoride in a fluorine-making electrolytic cell is characterized by comprising the following steps:

(1) checking the air tightness of the feeding device; the feeding device comprises a liquid hydrogen fluoride storage container, a liquid hydrogen fluoride feeding pipe and an electrolytic bath, wherein the liquid hydrogen fluoride storage container is connected with the liquid hydrogen fluoride feeding pipe; the liquid hydrogen fluoride feeding pipe comprises a main pipe and a plurality of branch pipes connected with the main pipe; the plurality of branch pipes respectively extend into the adjacent anode plates in the electrolytic bath, and liquid outlet holes are formed in the side walls of the extended branch pipes; the top of the liquid hydrogen fluoride storage container is provided with a nitrogen inlet;

(2) calculating the feeding amount of liquid hydrogen fluoride in the electrolytic cell according to the acidity range of the electrolytic cell;

(3) preparing an electrolytic bath feeding operation;

(4) sampling and analyzing electrolyte in the electrolytic cell;

(5) feeding liquid hydrogen fluoride into the electrolytic cell.

2. The method for centralized feeding of liquid hydrogen fluoride in fluorine-producing electrolytic cell according to claim 1, wherein the step (3) of cell charging operation preparation further comprises: and opening a nitrogen valve, and filling nitrogen into the liquid hydrogen fluoride storage container to keep the pressure in the liquid hydrogen fluoride storage container within the range of 0.15 +/-0.02 MPa.

3. The method for centralized feeding of liquid hydrogen fluoride in fluorine-producing electrolytic cell according to claim 1, wherein the step (4) of sampling and analyzing the electrolyte in the electrolytic cell further comprises: sampling and analyzing the electrolytic hyaluronic acid value of the target electrolytic cell, and recording the electronic scale indicating value of the electrolytic cell.

4. The method for intensively feeding liquid hydrogen fluoride in the fluorine-making electrolytic cell according to claim 1, wherein the acidity of the electrolytic cell in the step (2) is in the range of 38.5-40.2 wt%.

5. The method for centralized feeding of liquid hydrogen fluoride in fluorine-producing electrolytic cell according to claim 1, wherein the step (5) of feeding liquid hydrogen fluoride in electrolytic cell further comprises: the feeding rate of the liquid hydrogen fluoride is controlled to be 4.0-6.0kg/min, and the feeding time of a single electrolytic cell is controlled to be 10-15 min.

6. The method of claim 1, wherein the liquid hydrogen fluoride outlet holes are symmetrically arranged.

7. The method of claim 1, wherein the liquid hydrogen fluoride storage container is located at a higher position than the electrolytic cell.

8. The centralized feeding device of liquid hydrogen fluoride in fluorine-making electrolytic cell according to claim 1, wherein the main pipe is connected with 2-5 branch pipes.

9. The centralized feeding device of liquid hydrogen fluoride in fluorine-making electrolytic cell according to claim 1, wherein the liquid hydrogen fluoride storage container is connected with the liquid hydrogen fluoride feeding pipe through a feeding pipeline.

10. The centralized feeding device of liquid hydrogen fluoride in fluorine-making electrolytic cell according to any of claims 1 to 9, characterized in that an electronic scale is arranged at the bottom of the electrolytic cell.

Technical Field

The invention belongs to the field of electrolytic fluorine preparation, and particularly relates to a centralized feeding method of liquid hydrogen fluoride in a fluorine preparation electrolytic tank.

Background

As an important chemical raw material, fluorine gas is very active in chemical property and has very strong oxidizability, so that the process for preparing fluorine by molten salt electrolysis mainly takes an electrolytic bath as main equipment in industrial production: molten potassium bifluoride is added as an electrolyte to an electrolytic cell, and then fluorine gas is produced by the action of an electrode by continuously adding hydrogen fluoride to the electrolyte.

At present, domestic fluorine production electrolytic cells mainly adopt a gaseous hydrogen fluoride feeding mode: liquid hydrogen fluoride stored in a hydrogen fluoride evaporator is heated and evaporated to be converted into gaseous hydrogen fluoride, the gaseous hydrogen fluoride enters a hydrogen fluoride distribution tank after being filtered and dedusted, then is conveyed to an electrolytic cell through a feeding pipeline and is added into the electrolytic cell through a bubbling pipe, and is combined with molten electrolyte potassium bifluoride in the electrolytic cell to be converted into molten KH₂F₃Fluorine gas and hydrogen gas are generated by the electrodes. In the running process of the electrolytic cell, liquid hydrogen fluoride needs to be heated and evaporated in the evaporator before feeding the hydrogen fluoride, so that the hydrogen fluoride evaporator is easy to cause corrosion and leakage accidents; because the hydrogen fluoride is continuously consumed by electrolysis, in order to keep the acidity of the electrolyte within the process control range, gaseous hydrogen fluoride needs to be continuously added into the electrolytic cell, and the feeding efficiency is low; because hydrogen fluoride molecules have association properties and are difficult to realize accurate metering, the content of hydrogen fluoride in the molten salt electrolyte is difficult to control, and the hydrogen fluoride content of the electrolyte needs to be periodically sampled and analyzed to be used as a basis for adjusting the feeding amount of the hydrogen fluoride. The technology of foreign feeding process devices of fluorine-making electrolytic cells is reported only by information, and the liquid hydrogen fluoride feeding technology is adopted in France, but the specific feeding process flow and process devices are not clear.

The nuclear industry research institute of physical and chemical engineering (Tianjin) has developed a small-scale experiment for supplying liquid hydrogen fluoride in a fluorine-producing electrolytic cell, which mainly adopts a one-to-one supplying mode of a small-capacity hydrogen fluoride steel cylinder and an electrolytic cell: liquid hydrogen fluoride is subpackaged into small-capacity steel cylinders, each electrolytic cell is provided with one hydrogen fluoride steel cylinder, and whether the hydrogen fluoride steel cylinder needs to be added or not is determined according to the weight change of the electrolytic cell. The experimental equipment is dispersed, the feeding process is completely operated manually, the operation procedure is complicated, the safety risk is high, and the automation of process engineering control is not easy to realize.

Disclosure of Invention

The invention provides a centralized feeding method of liquid hydrogen fluoride in a fluorine-making electrolytic cell, aiming at solving the problems of complicated feeding operation procedure and higher safety risk of the liquid hydrogen fluoride in the fluorine-making electrolytic cell in the prior art.

The invention adopts the specific scheme that: a method for intensively feeding liquid hydrogen fluoride in a fluorine-producing electrolytic cell, which comprises the following steps:

(1) checking the air tightness of the feeding device; the feeding device comprises a liquid hydrogen fluoride storage container, a liquid hydrogen fluoride feeding pipe and an electrolytic bath, wherein the liquid hydrogen fluoride storage container is connected with the liquid hydrogen fluoride feeding pipe; the liquid hydrogen fluoride feeding pipe comprises a main pipe and a plurality of branch pipes connected with the main pipe; the plurality of branch pipes respectively extend into the adjacent anode plates in the electrolytic bath, and liquid outlet holes are formed in the side walls of the extended branch pipes; the top of the liquid hydrogen fluoride storage container is provided with a nitrogen inlet;

(2) calculating the feeding amount of liquid hydrogen fluoride in the electrolytic cell according to the acidity range of the electrolytic cell;

(3) preparing an electrolytic bath feeding operation;

(4) sampling and analyzing electrolyte in the electrolytic cell;

(5) feeding liquid hydrogen fluoride into the electrolytic cell.

The step (3) of preparing for the cell charging operation further comprises: and opening a nitrogen valve, and filling nitrogen into the liquid hydrogen fluoride storage container to keep the pressure in the liquid hydrogen fluoride storage container within the range of 0.15 +/-0.02 MPa.

The step (4) of sampling and analyzing the electrolyte in the electrolytic cell further comprises the following steps: sampling and analyzing the electrolytic hyaluronic acid value of the target electrolytic cell, and recording the electronic scale indicating value of the electrolytic cell.

The acidity range of the electrolytic cell in the step (2) is 38.5 to 40.2 weight percent.

The step (5) of feeding the electrolytic cell with liquid hydrogen fluoride further comprises the following steps: the feeding rate of the liquid hydrogen fluoride is controlled to be 4.0-6.0kg/min, and the feeding time of a single electrolytic cell is controlled to be 10-15 min.

The liquid outlet holes are symmetrically arranged.

The liquid hydrogen fluoride storage container is positioned higher than the electrolytic cell.

The main pipe is connected with 2-5 branch pipes.

The liquid hydrogen fluoride storage container is connected with the liquid hydrogen fluoride feeding pipe through a feeding pipeline.

An electronic scale is arranged at the bottom of the electrolytic cell. Compared with the prior art, the invention has the following beneficial effects:

1. according to the centralized feeding method of the liquid hydrogen fluoride in the fluorine-making electrolytic cell, provided by the invention, the feeding amount of the hydrogen fluoride in the electrolytic cell is calculated, and then the feeding operation preparation, the electrolyte sampling analysis and the liquid hydrogen fluoride feeding operation of the electrolytic cell are carried out, so that the problems of complicated feeding operation procedure and high operation risk of the liquid hydrogen fluoride in the fluorine-making electrolytic cell are solved.

2. In the process of feeding the liquid hydrogen fluoride in the fluorine-making electrolytic cell, only the feeding valve and the emptying valve need to be operated, and the parameters of the operation equipment and the monitoring process are few by monitoring the indicated value of the electrolytic cell electronic scale and the indicated value of the electrolytic cell pressure meter, so that the feeding operation is very simple and convenient, and the operation is convenient for personnel.

3. The liquid hydrogen fluoride storage container is adopted for liquid feeding, the hydrogen fluoride does not need to be heated and evaporated, the liquid hydrogen fluoride does not need to be transferred to other containers, and the liquid hydrogen fluoride is added into the electrolytic bath at normal temperature, so that the risk of equipment corrosion is greatly reduced.

Drawings

FIG. 1 is a schematic view of a feeding device according to the present invention;

FIG. 2 is a schematic view of a liquid hydrogen fluoride feed tube according to the present invention;

FIG. 3 is a schematic diagram showing the relative position of a liquid hydrogen fluoride feed tube and a carbon anode plate according to the present invention;

wherein the reference numerals are respectively:

1. a liquid hydrogen fluoride storage container 2, a feed valve; 3. a liquid hydrogen fluoride feed tube; 4. a main pipe; 5. a branch pipe; 6. an electrolytic cell; 7. a charging valve; 8. an emptying valve; 9. a nitrogen inlet; 10. nitrogen gas; 11. a filter; 12. a feed conduit; 13. an electronic scale; 14. a liquid outlet hole; 15. and (4) an anode plate.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

The invention provides a centralized feeding method of liquid hydrogen fluoride in a fluorine-making electrolytic cell, which comprises the following steps:

(1) checking the air tightness of the feeding device;

the feeding device comprises a liquid hydrogen fluoride storage container 1, a liquid hydrogen fluoride feeding pipe 3 and an electrolytic bath 6; the liquid hydrogen fluoride storage container 1 is connected with a liquid hydrogen fluoride feeding pipe 3; the liquid hydrogen fluoride feeding pipe 3 comprises a main pipe 4 and a plurality of branch pipes 5 connected with the main pipe 4; the plurality of branch pipes 5 respectively extend into the electrolytic bath 6 between the adjacent anode plates 15, and liquid outlet holes 14 are formed in the side walls of the extended branch pipes; the top of the liquid hydrogen fluoride storage container 1 is provided with a nitrogen inlet 9.

And an emptying valve 8 is arranged on the pipeline of the main pipe 4.

The liquid hydrogen fluoride storage container 1 is positioned higher than the electrolytic bath 6 to facilitate the flow of liquid.

The liquid hydrogen fluoride storage container 1 is communicated with the liquid hydrogen fluoride feeding pipe 3 through a feeding pipeline 12, and the main pipe 4 is communicated with 2-5 branch pipes 5.

The liquid hydrogen fluoride storage container 1 is connected with the liquid hydrogen fluoride feeding pipe 3 through a feeding pipeline 12. The liquid hydrogen fluoride enters a main pipe of the liquid hydrogen fluoride feeding pipe 3 from the liquid hydrogen fluoride storage container 1 through the feeding pipeline 12 under the action of nitrogen pressure, then is shunted to each branch pipe, and finally flows into the electrolytic cell through the liquid outlet hole.

The quantity of liquid hydrogen fluoride filling tube 3 is at least 2, the quantity of electrolysis trough 6 is at least 2, and liquid hydrogen fluoride filling tube 3 with electrolysis trough 6 one-to-one sets up.

And a feeding valve 2 and a feeding valve 7 are arranged on the pipeline of the feeding pipeline 12.

An electronic scale 13 is arranged at the bottom of the electrolytic cell 6.

(2) Calculating the hydrogen fluoride feeding amount in the electrolytic cell;

the chemical reaction principle is as follows:

dissolving hydrogen fluoride in potassium bifluoride: KHF₂+HF→KH₂F₃

Electrochemical reaction of hydrogen fluoride on the electrode:

anode: f^-→F+e^-

F+F→F₂↑

Cathode: h⁺-e^-→H

H+H→H₂↑

The mass of the electrolyte in the 10KA medium-temperature fluorine production electrolytic cell is 3840 kg-3860 kg, and the average value is 3850 kg. When the acidity of the electrolyte changes from 38.5% to 40.2%, the amount of hydrogen fluoride to be added is:

3850×(0.402-0.385)＝65.45(kg)

(3) preparing an electrolytic bath feeding operation;

(4) sampling and analyzing electrolyte; sampling and analyzing the electrolytic hyaluronic acid value of the target electrolytic cell, and recording the electronic scale indicating value of the electrolytic cell;

(5) feeding liquid hydrogen fluoride into the electrolytic cell; open liquid hydrogen fluoride charging valve, hydrogen fluoride in the liquid hydrogen fluoride storage container under the pressure effect through liquid hydrogen fluoride feed pipeline and liquid hydrogen fluoride filling tube, add the electrolysis trough in, when the electronic scale indicating value increases to a definite value, close liquid hydrogen fluoride charging valve.

The preparation work of the electrolytic cell feeding operation in the step (3) comprises the steps of opening a nitrogen valve, and filling a certain amount of nitrogen into a liquid hydrogen fluoride storage container to keep the pressure in the container within the range of 0.15 +/-0.02 MPa; and opening the feeding valve, filling the centralized feeding pipeline and the liquid hydrogen fluoride filter with liquid hydrogen fluoride, and closing the feeding valve and the emptying valve.

The step (3) of preparing for the cell charging operation further comprises: and opening a nitrogen valve, and filling nitrogen into the liquid hydrogen fluoride storage container to keep the pressure in the liquid hydrogen fluoride storage container within the range of 0.15 +/-0.02 MPa.

The step (4) of sampling and analyzing the electrolyte in the electrolytic cell further comprises the following steps: sampling and analyzing the electrolytic hyaluronic acid value of the target electrolytic cell, and recording the electronic scale indicating value of the electrolytic cell.

The acidity range of the electrolytic cell in the step (2) is 38.5 to 40.2 weight percent.

The step (5) of feeding the electrolytic cell with liquid hydrogen fluoride further comprises the following steps: the feeding rate of the liquid hydrogen fluoride is controlled to be 4.0-6.0kg/min, and the feeding time of a single electrolytic cell is controlled to be 10-15 min. According to the scheme of the invention, in the feeding process of the 10KA medium-temperature electrolytic cell, the pressure of the liquid hydrogen fluoride storage container is controlled to be 0.15 +/-0.01 MPa, the feeding rate of the liquid hydrogen fluoride is controlled to be about 5.0kg/min, the feeding time of a single electrolytic cell is controlled to be within the range of 12-15 min, the operation of the electrolytic cell is stable, the control parameters such as the cell temperature, the interpolar voltage, the electrolytic current and the like do not fluctuate greatly, and the feeding requirement of the 10KA electrolytic cell is met.

And (5) after the operation of the step (5) is finished, adjusting the pressure of the electrolytic cell, observing a pressure gauge of the electrolytic cell, and opening a vent valve to adjust the pressure of the electrolytic cell within a control requirement range if the pressure exceeds the control range.

The pressure of the electrolytic cell is 0.15 +/-0.01 MPa within the control requirement range.

The density of the liquid hydrogen fluoride at normal temperature is 0.945g/cm³(25 ℃ C.), density of electrolyte 1.91g/cm³(90 ℃), combining the structural design of the electrolytic cell and the electrolyte liquid sealing height, in order to ensure the uniform feeding of the liquid hydrogen fluoride, the feeding pipe comprises 1 main pipe and 3 branch pipes, the feeding directions of the 3 branch pipes are 1#, 2# and 3# in sequence,the lengths are 980mm, 750mm and 550mm respectively; the bottoms of the 1#, 2# and 3# branch pipes are respectively provided with 2, 4 and 6 phi 6 split lateral liquid outlet holes, and the liquid outlet direction of the liquid outlet holes is parallel to the side surface of the carbon anode plate. The number of the liquid outlet holes is increased in sequence along the sequence of the flow through the branch pipes, so that different requirements of different electrolytic tanks can be met.

According to the physical and chemical characteristics that liquid hydrogen fluoride and electrolyte have strong corrosivity, and the structural parameters of a 10KA medium-temperature fluorine production electrolytic cell and the characteristics of common chemical materials are combined, a liquid hydrogen fluoride storage container, a liquid hydrogen fluoride material pipeline, a filter, a valve and the like are made of low-carbon steel Q235, and a branch pipe of a liquid hydrogen fluoride feeding pipe is made of Monel 400.

The material supply pipeline and the material supply pipe main pipe adopt pipe diameters ofThe 3 branch pipes of the feed pipe adopt Monel400 pipe, emptying pipeline adoptedThe low-carbon steel pipe, the feeding valve and the feeding valve adopt DN32 low-carbon steel ball valves, and the emptying valve adopts DN20 low-carbon steel stop valves.

The mass of the electrolyte in the 10KA medium-temperature fluorine production electrolytic cell is calculated according to 3850kg, the acidity of the electrolyte is controlled to be 38.5-40.2% (wt), and the mass of the liquid hydrogen fluoride which needs to be added is 65kg when the acidity of the electrolyte in the electrolytic cell is increased from 38.5% to 40.2%.

As the hydrogen fluoride has strong volatility, in order to ensure the air tightness of the liquid hydrogen fluoride feeding process device, after the device is assembled, the nitrogen gas of 0.4Mpa (gauge pressure) is adopted for carrying out 24h air tightness test, and the leakage rate reaches the standard requirement of II-type pressure pipeline specification.

Example 1

A centralized feeding method of liquid hydrogen fluoride for a fluorine-making electrolytic tank is characterized in that a centralized feeding device of liquid hydrogen fluoride shown in the attached drawing is established by combining the condition of a 10KA medium-temperature electrolysis fluorine-making process system, and the centralized feeding operation of the liquid hydrogen fluoride for the fluorine-making electrolytic tank is carried out. The specific embodiment is as follows:

(1) air tightness test of feeding device

Because hydrogen fluoride has strong volatility, in order to guarantee liquid hydrogen fluoride feedway's gas tightness, liquid hydrogen fluoride concentrates feedway equipment to accomplish the back, adopts 0.4Mpa (gauge pressure) nitrogen gas to carry out 24h gas tightness inspection to feedway, lets out leakage quantity and reaches II type pressure pipeline standard requirements.

(2) Calculation of feed amount of electrolytic cell

The mass of the electrolyte in the 10KA medium-temperature fluorine production electrolytic cell is 3840 kg-3860 kg, and the average value is 3850 kg. When the acidity of the electrolyte changes from 38.5% to 40.2%, the amount of hydrogen fluoride to be added is:

3850×(0.402-0.385)＝65.45(kg)

(3) preparation of the cell for charging operations

And opening a nitrogen valve, filling a certain amount of nitrogen into the liquid hydrogen fluoride storage container to keep the pressure in the container within the range of 0.15MPa, opening a feeding valve, filling the centralized feeding pipeline and the liquid hydrogen fluoride filter with liquid hydrogen fluoride, and closing a feeding valve and an emptying valve.

(4) Electrolyte sampling analysis

Sampling and analyzing the electrolytic acid value of the target electrolytic cell according to the requirements of the electrolytic process, and recording the electronic scale indication value of the electrolytic cell when the acid value is close to 38.5 percent.

(5) Electrolytic cell liquid hydrogen fluoride charging operation

And opening a liquid hydrogen fluoride charging valve, adding the hydrogen fluoride in the liquid hydrogen fluoride storage container into the electrolytic cell through a liquid hydrogen fluoride feeding pipeline and a liquid hydrogen fluoride charging pipe under the action of pressure, and closing the liquid hydrogen fluoride charging valve when the value indicated by the electronic scale is increased by 65 kg. The feeding rate of the liquid hydrogen fluoride is controlled to be 6.0kg/min, and the feeding time of a single electrolytic cell is controlled to be within 15 min.

Example 2

(1) Air tightness test of feeding device

Because hydrogen fluoride has strong volatility, in order to guarantee liquid hydrogen fluoride feedway's gas tightness, liquid hydrogen fluoride concentrates feedway equipment to accomplish the back, adopts 0.4Mpa (gauge pressure) nitrogen gas to carry out 24h gas tightness inspection to feedway, lets out leakage quantity and reaches II type pressure pipeline standard requirements.

(2) Calculation of feed amount of electrolytic cell

The mass of the electrolyte in the 10KA medium-temperature fluorine production electrolytic cell is 3840 kg-3860 kg, and the average value is 3850 kg. When the acidity of the electrolyte changes from 38.5% to 40.2%, the amount of hydrogen fluoride to be added is:

3850×(0.402-0.385)＝65.45(kg)

(3) preparation of the cell for charging operations

And opening a nitrogen valve, filling a certain amount of nitrogen into the liquid hydrogen fluoride storage container to keep the pressure in the container within the range of 0.14MPa, opening a feeding valve, filling the centralized feeding pipeline and the liquid hydrogen fluoride filter with liquid hydrogen fluoride, and closing a feeding valve and an emptying valve.

(4) Electrolyte sampling analysis

Sampling and analyzing the electrolytic acid value of the target electrolytic cell according to the requirements of the electrolytic process, and recording the electronic scale indication value of the electrolytic cell when the acid value is close to 40.2 percent.

(5) Electrolytic cell liquid hydrogen fluoride charging operation

And opening a liquid hydrogen fluoride charging valve, adding the hydrogen fluoride in the liquid hydrogen fluoride storage container into the electrolytic cell through a liquid hydrogen fluoride feeding pipeline and a liquid hydrogen fluoride charging pipe under the action of pressure, and closing the liquid hydrogen fluoride charging valve when the value indicated by the electronic scale is increased by 65 kg. The feeding rate of the liquid hydrogen fluoride is controlled to be 4.0kg/min, and the feeding time of a single electrolytic cell is controlled to be within 10 min.

Example 3

A centralized feeding method of liquid hydrogen fluoride for a fluorine-making electrolytic tank is characterized in that a centralized feeding device of liquid hydrogen fluoride shown in the attached drawing is established by combining the condition of a 10KA medium-temperature electrolysis fluorine-making process system, and the centralized feeding operation of the liquid hydrogen fluoride for the fluorine-making electrolytic tank is carried out. The specific embodiment is as follows:

(1) air tightness test of feeding device

Because hydrogen fluoride has strong volatility, in order to guarantee liquid hydrogen fluoride feedway's gas tightness, liquid hydrogen fluoride concentrates feedway equipment to accomplish the back, adopts 0.4Mpa (gauge pressure) nitrogen gas to carry out 24h gas tightness inspection to feedway, lets out leakage quantity and reaches II type pressure pipeline standard requirements.

(2) Calculation of feed amount of electrolytic cell

The mass of the electrolyte in the 10KA medium-temperature fluorine production electrolytic cell is 3840 kg-3860 kg, and the average value is 3850 kg. When the acidity of the electrolyte changes from 38.5% to 40.2%, the amount of hydrogen fluoride to be added is:

3850×(0.402-0.385)＝65.45(kg)

(3) preparation of the cell for charging operations

And opening a nitrogen valve, filling a certain amount of nitrogen into the liquid hydrogen fluoride storage container to keep the pressure in the container within the range of 0.16MPa, opening a feeding valve, filling the centralized feeding pipeline and the liquid hydrogen fluoride filter with liquid hydrogen fluoride, and closing a feeding valve and an emptying valve.

(4) Electrolyte sampling analysis

Sampling and analyzing the electrolytic acid value of the target electrolytic cell according to the requirements of the electrolytic process, and recording the electronic scale indication value of the electrolytic cell when the acid value is close to 39.5 percent.

(5) Electrolytic cell liquid hydrogen fluoride charging operation

And opening a liquid hydrogen fluoride charging valve, adding the hydrogen fluoride in the liquid hydrogen fluoride storage container into the electrolytic cell through a liquid hydrogen fluoride feeding pipeline and a liquid hydrogen fluoride charging pipe under the action of pressure, and closing the liquid hydrogen fluoride charging valve when the value indicated by the electronic scale is increased by 65 kg. The feeding rate of the liquid hydrogen fluoride is controlled to be 5.0kg/min, and the feeding time of a single electrolytic cell is controlled to be within 13 min.

In addition, if automatic control interlocking is arranged between the pressure in the liquid hydrogen fluoride storage container and the nitrogen storage container, between the electronic scale of the electrolytic cell and the charging valve and between the pressure in the electrolytic cell and the emptying valve, the automatic control function of the whole charging process can be realized by adopting simple PLC control, thereby effectively improving the automation level of electrolytic fluorine production.

The invention solves the problems of complicated feeding operation procedure and larger safety risk of liquid hydrogen fluoride in the fluorine-making electrolytic cell in the prior art; the method provided by the invention is simple and high in charging efficiency.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications may be made to the above-described embodiments, and it is not necessary, nor is it intended to be exhaustive of all the embodiments. And obvious variations or modifications therefrom are intended to be within the scope of the invention.