An on-line sampling system and method for trace fluoride samples in a vacuum system

Abstract

The present application belongs to the field of analytical technique, and particularly relates to an online sampling system and method for trace fluoride sample in vacuum system. The online sampling system comprises a vacuum container, an orifice plate, an adjusting valve, a hydrolysis device and a freezing container connected in sequence through pipelines. The input end of the vacuum container is connected with a tail pipe and a gas supply cylinder respectively. The hydrolysis device comprises a plurality of hydrolysis bottles connected in sequence. The present application uses the online sampling hydrolysis method to take trace fluoride sample for hydrolysis under the normal operation state of the system, thereby avoiding the problem of long sampling time of the freezing method and the error caused by inaccurate weighing. In order to meet the instrument test requirements, the dilution multiple of the conventional freezing method is 1000-2000 times of the present method. The present method can take trace sample, thereby avoiding the problems of large dilution multiple and large uncertainty of the freezing method, and does not need to break the vacuum, thus avoiding the loss of sample volatilization, and greatly improving the accuracy of the analysis result.

Description

Technical Field

[0001] This invention belongs to the field of analytical technology, and in particular relates to an online sampling system and method for trace fluoride samples in a vacuum system to ensure uninterrupted experimentation. Background Technology

[0002] One key technology in researching the separation and recovery of waste washing materials is the study of methods for analyzing the composition of these materials. The sampling method significantly impacts the accuracy of the analytical results. Currently, the sampling method used is cryogenic sampling. The sampler itself is relatively heavy, leading to significant weighing errors when weighing samples in the milligram and gram ranges, thus affecting the accuracy of the analytical results. This method typically involves sample volumes in the hundreds of milligrams to grams, requiring significant dilution to meet the injection range required by the analytical instruments, increasing uncertainty. Furthermore, the hydrolysis process after cryogenic sampling requires breaking up the vacuum, potentially resulting in sample loss and affecting the analytical results. Therefore, a new vacuum system and method for sampling trace fluoride samples are needed. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention designs an online sampling and hydrolysis system and method for trace fluoride samples in a vacuum system. Using this method, a trace sample is taken for hydrolysis while the system is operating normally, avoiding the problems of time-consuming sampling with a sampler, inaccurate weighing, and biases in analytical data. Furthermore, because a trace sample can be taken, the problem of increased uncertainty caused by large dilution factors in hydrolysis is avoided.

[0004] The technical solution adopted by the present invention to solve this problem is as follows:

[0005] An online sampling system for trace fluoride samples in a vacuum system includes a vacuum container, an orifice plate, a regulating valve, a hydrolysis device, and a freezing container connected in sequence by pipelines. The input end of the vacuum container is connected to a tail pipe and a gas supply cylinder, respectively. The hydrolysis device includes several hydrolysis bottles connected in series.

[0006] Preferably, a first pressure gauge is installed on the pipeline between the orifice plate and the regulating valve, and a second pressure gauge is installed on the vacuum container, wherein the vacuum container is a 1L vacuum container.

[0007] More preferably, valves are provided on the pipeline between the tail material pipe and the vacuum container, and on the pipeline between the gas supply cylinder and the vacuum container.

[0008] In a further preferred embodiment, a mass flow meter is also provided on the pipeline between the gas supply cylinder and the vacuum container.

[0009] More preferably, the gas supply cylinder is a nitrogen cylinder.

[0010] More preferably, connectors are installed on the pipelines before and after the hydrolysis device.

[0011] More preferably, the hydrolysis device includes at least three hydrolysis bottles connected in series, each containing a hydrolysate, with an inlet pipe extending below the surface of the hydrolysate and the hydrolysate level in the bottle being close to but below the height of the outlet pipe.

[0012] More preferably, the freezing container is a 1L freezing container, which is connected in parallel to the pipeline after the hydrolysis device, and the freezing container is provided with inlet and outlet valves respectively.

[0013] Further preferably, valves, pressure gauges, or flow meters are also installed on each of the pipelines.

[0014] The second objective of this invention is to provide an online sampling method for trace fluoride samples in a vacuum system, comprising the following steps:

[0015] Step 1: After connecting each hydrolysis bottle and verifying its good sealing performance, connect the vacuum container, orifice plate, regulating valve, and freezing container through pipelines. The input end of the vacuum container is connected to the tail pipe and the gas supply cylinder respectively to perform vacuum leak detection.

[0016] Step 2: After the vacuum leak test is passed, prepare a hydrolysate of a certain concentration, inject it evenly into each hydrolysis bottle, and connect the hydrolysis device to the system.

[0017] Step 3: Introduce the BrF3 gas to be analyzed into the vacuum container through the tail pipe at a pressure of 100 Pa, and then close the valve between the vacuum container and the tail pipe.

[0018] Step 4: After depressurizing the high-purity nitrogen in the gas supply cylinder, place it into a vacuum container until the pressure in the vacuum container is slightly higher than the atmospheric pressure by 3-5 kPa. Then, close the valve between the vacuum container and the gas supply cylinder to stop supplying nitrogen.

[0019] Step 5: Open the valve between the hydrolysis bottle and the freezing container, and ensure that the regulating valve is closed. Then slowly open the regulating valve and continuously introduce high-purity nitrogen into the vacuum container. The nitrogen carries BrF3 into the hydrolysate. The flow rate of nitrogen is controlled by a mass flow meter to ensure that the hydrolysis process proceeds smoothly and quickly.

[0020] Step 6: When the total volume of nitrogen gas introduced into the vacuum container is greater than five times the volume of the container itself, it can be assumed that all the tailings have been introduced into the hydrolysate. At this point, stop the supply of nitrogen gas and close the valve between the vacuum container and the gas supply cylinder.

[0021] Step 7: Close the inlet and outlet valves of the freezing container, remove the hydrolysis device, mix the hydrolysates from each bottle, and wash the hydrolysis bottles with 400mL of deionized water before analyzing them in the instrument.

[0022] Preferably, in step two, the hydrolysate is a solution of a certain concentration prepared by adding an excess of sodium thiosulfate or sodium sulfite to 600 mL of deionized water.

[0023] The advantages and positive effects of this invention are:

[0024] 1. This invention utilizes an online sampling hydrolysis method. Under normal system operation, a trace amount of fluorine-containing sample is taken for hydrolysis, avoiding the problems of long sampling time and inaccurate weighing caused by the freezing method. To meet instrument testing requirements, the dilution factor of the conventional freezing method is 1000-2000 times that of this method. This method can take trace amounts of sample, avoiding the problems of large dilution factors and high uncertainty in freezing sampling and hydrolysis. Furthermore, this method does not require breaking the cavity, thus eliminating sample loss due to evaporation, greatly improving the accuracy of the analytical results.

[0025] 2. This invention can complete online sampling and hydrolysis while ensuring the normal operation of the experimental system, and can hydrolyze trace amounts of sample by controlling the injection pressure. Attached Figure Description

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless specifically indicated, these drawings are intended only to conceptually illustrate the structural construction described herein and are not necessarily drawn to scale.

[0027] Figure 1 This is a schematic diagram of the sampling of trace fluoride samples in this invention.

[0028] In the diagram: 1-orifice plate, 2-first pressure gauge, 3-regulating valve, 4-hydrolysis device, 5-connector, 6-freezing container, 7-nitrogen cylinder, 8-vacuum container. Detailed Implementation

[0029] First, it should be noted that the specific structure, features, and advantages of the present invention will be described in detail below by way of examples. However, all descriptions are for illustrative purposes only and should not be construed as limiting the present invention in any way. Furthermore, any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the accompanying drawings, can still be arbitrarily combined or deleted among these technical features (or their equivalents) to obtain more other embodiments of the present invention that may not be directly mentioned herein. Additionally, for the sake of simplifying the drawings, the same or similar technical features may be indicated only in one place in the same drawing.

[0030] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," and "screw-in" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. The invention will now be described in detail with reference to the accompanying drawings.

[0031] Example 1:

[0032] An online sampling system for trace fluoride samples in a vacuum system includes a vacuum container 8, an orifice plate 1, a regulating valve 3, a hydrolysis device 4, and a freezing container 6 connected in sequence by pipelines. The input end of the vacuum container 8 is connected to the tail pipe and the gas supply cylinder, respectively. The hydrolysis device 4 includes a number of hydrolysis bottles connected in series.

[0033] In this embodiment, during the preparation stage, several hydrolysis bottles are connected in series and their sealing performance is tested. After confirming that the sealing performance is good, the bottles are then connected to the pipeline according to... Figure 1The system connects vacuum container 8, orifice plate 1, regulating valve 3, and freezing container 6. After passing vacuum leak testing, the prepared hydrolysate is evenly injected into each hydrolysis bottle, and the hydrolysis device is connected to the above system. Preferably, the freezing container is 1L, and the vacuum container 8 is preferably a 1L vacuum container. A trace amount of fluorine-containing sample is introduced into the 1L vacuum container through the tail pipe. When the pressure reaches 100Pa, the 1L vacuum container is disconnected from the tail pipe. High-purity nitrogen from the gas supply cylinder is depressurized and placed into the 1L vacuum container until the pressure in the 1L vacuum container is slightly higher than the atmospheric pressure by 3kPa-5kPa (ensuring that the hydrolysate does not backflow). Nitrogen supply is stopped, the valve between the hydrolysis bottle and the 1L freezing container is opened, ensuring the valve before the pump is closed. The regulating valve 3 between the 1L vacuum container and the hydrolysis bottle is slowly opened, continuously introducing nitrogen into the 1L vacuum container. High-purity nitrogen gas is used to carry BrF3 into the hydrolysate. The flow rate of nitrogen gas is controlled by a mass flow meter to ensure a stable and rapid hydrolysis process. When the total volume of nitrogen gas introduced into the 1L vacuum container is greater than five times the volume of the container itself, it can be considered that all the tailings have been introduced into the hydrolysate. At this point, the nitrogen gas supply is stopped, the regulating valve between the 1L vacuum container and the hydrolysis bottle is disconnected, the inlet and outlet valves of the 1L refrigeration container are closed, the hydrolysis device is removed, the hydrolysates from each bottle are mixed, and the hydrolysis bottles are washed with 400mL of deionized water before being analyzed by the instrument.

[0034] This technical solution utilizes an online sampling and hydrolysis method. Under normal system operation, a trace amount of fluorine-containing sample is taken for hydrolysis, avoiding the problems of long sampling times and inaccurate weighing caused by the freezing method. To meet instrument testing requirements, the dilution factor of the conventional freezing method is 1000–2000 times that of this method. This method can take trace amounts of sample, avoiding the problems of large dilution factors and high uncertainty associated with freezing sampling and hydrolysis. Furthermore, this method does not require breaking the vacuum, thus eliminating sample loss due to evaporation, significantly improving the accuracy of the analytical results.

[0035] Furthermore, in this embodiment, a first pressure gauge 2 is installed on the pipeline between the orifice plate 1 and the regulating valve 3. The first pressure gauge 2 is used to measure and display the pressure of the gas passing through it. A second pressure gauge is installed on the vacuum container 8. The second pressure gauge is used to measure and display the pressure inside the vacuum container 8.

[0036] Furthermore, in this embodiment, valves are provided on the pipeline between the tail material pipe and the vacuum container 8, and on the pipeline between the gas supply cylinder and the vacuum container 8, respectively, to control the opening and closing of the two pipelines.

[0037] Furthermore, in this embodiment, a mass flow meter is also provided on the pipeline between the gas supply cylinder and the vacuum container 8. The mass flow meter is used to measure the amount of gas introduced into the vacuum container 8.

[0038] Furthermore, in this embodiment, the gas supply cylinder is a nitrogen cylinder 7.

[0039] Furthermore, in this embodiment, connectors 5 are installed on the pipelines before and after the hydrolysis device 4. These connectors 5 serve as detachable structures on the pipelines, allowing the two pipelines to be connected as one unit during assembly and separated during disassembly. That is, the hydrolysis device 4 can be freely installed into or removed from the system via the two connectors 5, ensuring online sampling and hydrolysis can be completed while the system is operating normally. This online sampling method using the above system can be described as an online sampling method for trace fluoride samples used to ensure uninterrupted experimentation.

[0040] Furthermore, in this embodiment, the hydrolysis device 4 includes at least three hydrolysis bottles connected in series, such as... Figure 1 As shown, taking this embodiment as an example, the hydrolysis device 4 includes three hydrolysis bottles connected in series. The following is an example of the three hydrolysis bottles. Each of the three hydrolysis bottles is filled with hydrolysate. The air inlet pipe in the hydrolysis bottle extends below the surface of the hydrolysate. The surface of the hydrolysate in the hydrolysis bottle is close to but lower than the height of the air outlet pipe to prevent backflow.

[0041] Furthermore, in this embodiment, the freezing container 6 is connected in parallel to the pipeline behind the hydrolysis device 4. The inlet and outlet of the freezing container 6 are respectively equipped with inlet and outlet valves, which can control the opening and closing of the inlet and outlet of the freezing container 6.

[0042] Furthermore, in this embodiment, valves, pressure gauges, flow meters, or other instruments may also be installed on each of the pipelines.

[0043] Working principle: The operation method of this online sampling system is as follows: First, follow the instructions... Figure 1 Connect the orifice plate, instrument, valves, connectors, 1L refrigerated container, and vacuum pump. Ensure the vacuum leak test is successful. Then, inject hydrolysate into the hydrolysis flasks, ensuring the hydrolysate level is close to but below the outlet pipe to prevent backflow. Adjust the pressure to a suitable range of tens to one hundred Pascals to allow the sample to be analyzed to enter the hydrolysis flasks for hydrolysis. After stopping sampling, disassemble the hydrolysis flasks and mix them together. Add the eluent from the hydrolysis flasks to the hydrolysate. The hydrolysate can then be directly analyzed by the instrument.

[0044] Example 2:

[0045] An online sampling method for trace fluoride samples in a vacuum system includes the following steps:

[0046] Step 1: After connecting the three hydrolysis bottles and verifying their good sealing performance, connect the vacuum container 8, orifice plate 1, regulating valve 3, and freezing container 6 through pipelines. The input end of the vacuum container 8 is connected to the tail pipe and the gas supply cylinder respectively to perform vacuum leak detection.

[0047] Step 2: After the vacuum leak test is passed, prepare a certain concentration of hydrolysate: inject it evenly into 3 hydrolysis bottles, connect the hydrolysis device to the system, wherein: the hydrolysate level is close to but lower than the height of the gas outlet pipe to prevent backflow.

[0048] Step 3: Adjust the pressure to a suitable range of tens to hundreds of Pascals to allow the sample to be analyzed to enter the hydrolysis bottle for hydrolysis. Specifically: introduce the BrF3 gas to be analyzed into the 1L vacuum container through the tail pipe at a pressure of 100 Pa, and then close the valve between the 1L vacuum container and the tail pipe.

[0049] Step 4: After depressurizing the high-purity nitrogen in the gas supply cylinder, put it into a 1L vacuum container until the pressure in the 1L vacuum container is slightly higher than the atmospheric pressure by 3kPa-5kPa. Then close the valve between the 1L vacuum container and the gas supply cylinder to stop supplying nitrogen.

[0050] Step 5: Open the valve between the hydrolysis bottle and the 1L freezing container, and ensure that the regulating valve 3 is closed. Then slowly open the regulating valve 3 and continuously introduce high-purity nitrogen into the 1L vacuum container. The nitrogen carries BrF3 into the hydrolysate. The flow rate of nitrogen is controlled by a mass flow meter to ensure that the hydrolysis process proceeds smoothly and quickly.

[0051] Step 6: When the total volume of nitrogen gas introduced into the 1L vacuum container is greater than five times the volume of the container itself, it can be assumed that all the tailings have been introduced into the hydrolysate. At this point, stop the nitrogen supply and close the valve between the 1L vacuum container and the gas supply cylinder.

[0052] Step 7: Close the inlet and outlet valves of the 1L frozen container, remove the hydrolysis device, mix the three hydrolysates, and wash the hydrolysis bottles with 400mL of deionized water before analyzing them in the instrument.

[0053] Furthermore, in this embodiment, the hydrolysate in step two is prepared by adding an excess of sodium thiosulfate or sodium sulfite to 600 mL of deionized water to form a solution of a certain concentration.

[0054] Example 3:

[0055] As shown in the table below, the concentrations of each element in the hydrolysate are calculated after hydrolyzing two fluoride gases with 1L of deionized water using a 1L vacuum container and a sampling pressure of 1hPa.

[0056] Sampling objects Br element F element <![CDATA[BrF3]]> 3.28 mg / L 2.34 mg / L

[0057] The table above shows that if 1L of fluoride gas BrF3 at a pressure of 1hPa is hydrolyzed in 1L of water, the highest concentrations of Br and F in the hydrolysate are 6.56 mg / L and 2.34 mg / L, respectively, which meet the detection requirements of the analytical instrument. However, if the conventional freezing method is used to obtain the same concentration, it would require a dilution of at least 1000 to 2000 times, and the cavitation hydrolysis after freezing may result in sample loss.

[0058] In summary, this system and method can complete online sampling and hydrolysis while ensuring the normal operation of the experimental system, and can hydrolyze trace amounts of sample by controlling the injection pressure.

[0059] The above embodiments have provided a detailed description of the present invention, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. An online sampling method for trace fluoride samples in a vacuum system, characterized in that: An online sampling system for trace fluoride samples in a vacuum system is provided. The online sampling system includes a vacuum container (8), an orifice plate (1), a regulating valve (3), a hydrolysis device (4), and a freezing container (6) connected in sequence by pipelines. The input end of the vacuum container (8) is connected to the tail pipe and the gas supply cylinder, respectively. The hydrolysis device (4) includes at least three hydrolysis bottles connected in series. The hydrolysis bottles are filled with hydrolysate. The gas inlet pipe in the hydrolysis bottle extends below the surface of the hydrolysate. The surface of the hydrolysate in the hydrolysis bottle is close to but lower than the height of the gas outlet pipe. The freezing container (6) is connected in parallel to the pipeline behind the hydrolysis device (4). The inlet and outlet of the freezing container (6) are respectively provided with inlet and outlet valves. The online sampling method includes the following steps: Step 1: After connecting each hydrolysis bottle and verifying that its sealing performance is good, connect the vacuum container (8), orifice plate (1), regulating valve (3) and freezing container (6) through pipelines. The input end of the vacuum container (8) is connected to the tail pipe and the gas supply cylinder respectively to perform vacuum leak detection. Step 2: After the vacuum leak test is passed, prepare a hydrolysate of a certain concentration, inject it evenly into each hydrolysis bottle, and connect the hydrolysis device to the system. Step 3: Introduce the BrF3 gas to be analyzed into the vacuum container (8) through the tail pipe at a pressure of 100 Pa, and then close the valve between the vacuum container (8) and the tail pipe; Step 4: After depressurizing the high-purity nitrogen in the gas supply cylinder, place it into the vacuum container (8) until the pressure in the vacuum container (8) is slightly higher than the atmospheric pressure at that time by 3kPa-5kPa. Then close the valve between the vacuum container (8) and the gas supply cylinder to stop supplying nitrogen. Step 5: Open the valve between the hydrolysis bottle and the freezing container, and ensure that the regulating valve (3) is closed. Then slowly open the regulating valve (3) and continuously introduce high-purity nitrogen into the vacuum container (8). BrF3 is blown into the hydrolysate by the nitrogen. The flow rate of nitrogen is controlled by the mass flow meter to ensure that the hydrolysis process proceeds smoothly and quickly. Step 6: When the total volume of nitrogen gas introduced into the vacuum container (8) is greater than five times the volume of the container itself, it can be considered that all the tailings have been introduced into the hydrolysate. At this time, stop the supply of nitrogen gas and close the valve between the vacuum container (8) and the gas supply cylinder. Step 7: Close the inlet and outlet valves of the freezing container, remove the hydrolysis device, mix the hydrolysates from each bottle, and wash the hydrolysis bottles with 400mL of deionized water before analyzing them in the instrument.

2. The online sampling method for trace fluoride samples in a vacuum system according to claim 1, characterized in that: A first pressure gauge (2) is installed on the pipeline between the orifice plate (1) and the regulating valve (3), and a second pressure gauge is installed on the vacuum container (8). The vacuum container (8) is a 1L vacuum container.

3. The online sampling method for trace fluoride samples in a vacuum system according to claim 2, characterized in that: Valves are provided on the pipeline between the tail material pipe and the vacuum container (8) and on the pipeline between the gas supply cylinder and the vacuum container (8).

4. The online sampling method for trace fluoride samples in a vacuum system according to claim 3, characterized in that: A mass flow meter is also installed on the pipeline between the gas supply cylinder and the vacuum container (8).

5. The online sampling method for trace fluoride samples in a vacuum system according to claim 4, characterized in that: The gas supply cylinder is a nitrogen cylinder (7).

6. The online sampling method for trace fluoride samples in a vacuum system according to claim 1, characterized in that: Connectors (5) are installed on the pipelines at the front and rear of the hydrolysis device (4).

7. The online sampling method for trace fluoride samples in a vacuum system according to claim 1, characterized in that: In step two, the hydrolysate is a solution of a certain concentration prepared by adding excess sodium thiosulfate or sodium sulfite to 600 mL of deionized water.

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