A device for preparing a quantitative standard gas of methanol in nitrogen and application thereof

Abstract

This invention relates to the field of standard gas technology and discloses a quantitative device for preparing methanol standard gas in nitrogen and its application. The device includes a quantitative chamber, a component chamber connected to the quantitative chamber, a pressure regulating component disposed in the quantitative chamber, and a pressure dividing component disposed in the component chamber. This device can significantly improve the accuracy of transferring methanol gas into a gas cylinder and significantly reduce the error value generated during the transfer process. It can accurately and quantitatively transfer methanol gas into a gas cylinder. The weight error generated after using this device is within three ten-thousandths, which is small and accurate. In addition, this application realizes the quantitative measurement of gas through the quantitative chamber, component chamber and other structures. At the same time, the excess gas generated during the measurement process is stored in the component chamber and will not be emitted to the outside, making it safe and environmentally friendly to use.

Description

Technical Field

[0001] This invention relates to the field of standard gas technology, and in particular to a quantitative device for preparing methanol standard gas in nitrogen and its application. Background Technology

[0002] Methanol in nitrogen standard gas is a standard mixture of nitrogen and methanol, primarily used to detect methanol content in environmental analyses. It is a widely used standard gas in the detection field. Currently, the main method for preparing methanol in nitrogen standard gas is the gravimetric method, as specified in GB / T 5274.1-2018, Preparation of Mixed Gases for Gas Analysis Calibration - Part 1: Preparation of Primary Mixed Gases by Weighing Method. This method involves weighing the total mass of the gas cylinder, methanol, and nitrogen to determine the mole fraction of methanol in the cylinder.

[0003] Methanol is a liquid at room temperature. When preparing methanol standard gas in nitrogen, an organic vaporization device is needed to first vaporize the liquid methanol into methanol gas, and then quantitatively transfer the methanol gas to a gas cylinder for later use. Currently, there are two main methods for quantitatively transferring methanol to the gas cylinder. The first method involves weighing the liquid methanol using a syringe, heating and vaporizing it into methanol gas, and then transferring it to the gas cylinder. However, because the component has a large dead volume, complex structure, and cumbersome operation, this method cannot completely transfer the methanol gas in actual production. The weighing and injection of the liquid methanol are affected by many factors, leading to errors between the weighed liquid value and the actual amount of methanol transferred to the gas cylinder, resulting in poor gas preparation accuracy. The second method involves vaporizing the liquid methanol into methanol gas through heating, then filling a metering loop, and finally transferring the methanol gas from the metering loop to the gas cylinder, weighing the methanol gas during the transfer process. This eliminates the need to weigh the liquid methanol, reducing the number of process steps. However, in actual use, it was found that because the gas cylinder is connected to the injection component of the organic vaporization device, the weight during weighing will include a portion of the weight of the injection component. Therefore, when the injection component is disconnected from the gas cylinder, the weighing value will decrease. Thus, it is difficult to use this method to accurately control the entry of methanol gas into the gas cylinder during the weighing process. Summary of the Invention

[0004] To overcome the problem in the existing technology that methanol gas cannot be accurately transferred to the gas cylinder during the preparation of methanol standard gas in nitrogen, this application provides a quantitative device for preparing methanol standard gas in nitrogen and its application. When preparing methanol standard gas in nitrogen, the device buffers methanol gas in the quantitative chamber, eliminating the influence of the organic vaporization device on the weight during weighing. Then, by quantitatively recording the amount of methanol gas in the quantitative chamber and quantitatively removing the remaining methanol gas in the quantitative chamber, the technical effect of quantitatively transferring methanol gas to the gas cylinder is achieved. This device can accurately transfer methanol gas to the gas cylinder with high accuracy and can avoid the influence of other interfering factors.

[0005] The specific technical solution of this invention is as follows: A quantitative device for preparing methanol standard gas in nitrogen includes a quantitative chamber, a component chamber connected to the quantitative chamber, a pressure regulating component disposed in the quantitative chamber, and a pressure dividing component disposed in the component chamber.

[0006] In practical application, it has been found that two methods are commonly used when preparing methanol standard gas in nitrogen using the weighing method. One method involves using an organic vaporization device to vaporize a fixed amount of liquid methanol into methanol gas, and then injecting all the methanol gas into a gas cylinder. However, in practice, it has been found that some methanol gas remains in the organic vaporization device, resulting in errors. The other method involves using an organic vaporization device to pressurize and vaporize methanol gas, and then transferring the methanol gas into a gas cylinder, weighing the cylinder in real time during the transfer. However, this method makes it difficult to accurately control the amount of methanol gas injected. Furthermore, since the organic vaporization device and the gas cylinder are connected in real time, the real-time weighing value decreases when the device is separated, causing further errors. Therefore, to address these problems, this application provides a quantitative device for preparing methanol standard gas in nitrogen. This device consists of a quantitative chamber, a fractionation chamber, a pressure regulating component, and a pressure dividing component. This application connects the methanol standard gas quantitative device between the gas cylinder and the organic vaporization device, and uses methanol standard gas... The gas cylinder metering device buffers a portion of the methanol gas in the metering chamber. Since the volume of the metering chamber is fixed, when methanol gas is buffered in the metering chamber, the weight of the methanol gas in the capacity chamber can be calculated using the density of the methanol gas and the volume of the capacity chamber. Then, the gas inside the capacity chamber is used to precisely replenish the gas storage tank. The principle of precise metering replenishment is as follows: at the end of methanol gas injection, a portion of methanol gas is reserved in the capacity chamber. The weighing value at this time is the sum of the actual weight of methanol gas filled into the gas cylinder and the weight of methanol gas buffered in the metering chamber, i.e., the standard weight. The weight to be added to the gas cylinder in this application is the target weight. The difference between the standard weight and the weight of methanol gas in the capacity chamber can be used to calculate the actual weight of methanol gas filled into the gas cylinder. Then, the difference between the target weight and the actual weight of methanol gas filled into the gas cylinder determines the required weight of methanol gas to be replenished into the gas cylinder. Finally, the methanol gas in the metering chamber is measured through the metering chamber, the component chamber, the pressure regulating element, and the pressure dividing element. The measured amount is the weight of methanol gas to be replenished to the gas storage device.

[0007] The above-mentioned measurement process is achieved through a quantitative chamber, a component chamber, a pressure regulating element, and a pressure dividing element. The pressure regulating element is located inside the quantitative chamber and can adjust the volume of the quantitative chamber. After the volume inside the quantitative chamber changes, the weight of the methanol gas inside changes, thereby realizing the measurement of methanol gas. In addition, since the gas measurement process is relatively difficult, this application provides a component chamber connected to the quantitative chamber and a pressure dividing element located inside the component chamber. When the volume of the quantitative chamber is changed using the pressure regulating element, the pressure regulating element will squeeze the gas inside the quantitative chamber into the component chamber. When the gas enters the component chamber, it will push the pressure dividing element to change the volume of the component chamber to accommodate the methanol gas flowing in from the quantitative chamber. When the pressure regulating element is adjusted to the required position, it will block the component chamber and the quantitative chamber, thereby realizing the measurement of methanol gas in the quantitative chamber. Using the above device can ensure accurate gas measurement. At the same time, excess gas during the separation process is recovered inside the component chamber and will not escape to the outside, making it safer to use and easier to operate.

[0008] The target weight of this application is less than the standard weight, and the difference between the target weight and the labeled weight is within the range of the volumetric cavity.

[0009] Preferably, the pressure regulating component includes a metering valve stem located in the metering chamber and a pressure regulating sealing end sleeved on the outer wall of the metering chamber.

[0010] Preferably, the metering valve stem is matched with the metering cavity, and the sealing end is threadedly connected to the outer wall of the metering cavity.

[0011] Preferably, the outer wall of the quantitative cavity is provided with graduation lines.

[0012] The pressure regulating component of this application includes a metering valve stem and a pressure regulating sealing end. Since the device provided in this application measures gas, airtightness is the primary concern. Matching the metering valve stem with the metering cavity ensures airtightness. To further guarantee airtightness, this application also includes a pressure regulating sealing end, which is sleeved on the outside of the metering valve stem and threaded to the outer wall of the metering cavity. Furthermore, rotating the pressure regulating sealing end allows it to move in the extension direction of the metering cavity, thereby moving the metering valve stem inside the metering cavity. This achieves the technical effect of changing the volume of the metering cavity using the pressure regulating component. The end face of the metering valve stem located inside the volumetric cavity must be flush with the end face of the pressure regulating sealing end. Adjusting the pressure regulating sealing end according to the scale lines on the outer wall of the metering cavity ensures the accuracy of the metering valve stem located within the metering cavity.

[0013] Preferably, the metering valve stem is provided with a valve stem through hole, and a gas guide is provided in the valve stem through hole. One end of the gas guide is located in the valve stem through hole, and the other end is located outside the valve stem through hole. A gas guide valve is provided on the gas guide located outside the valve stem through hole.

[0014] The function of the gas guide on the metering valve stem of this application is to transfer methanol gas into the volumetric chamber through the gas guide, and the gas guide valve can control the flow of gas in the gas guide.

[0015] Preferably, the metering chamber is provided with a gas distribution hole, which connects the metering chamber and the component chamber. The metering chamber is provided with a guide groove, and a first valve is provided in the guide groove and slidably connected to the guide groove. The first valve is provided with a through hole that matches the gas distribution hole, and a one-way membrane is provided in the through hole.

[0016] Preferably, the one-way membrane control gas flows from the metering chamber into the component chamber.

[0017] In this application, a gas distribution hole is provided at the connection between the metering chamber and the component chamber. The gas distribution hole allows methanol gas to flow from the metering chamber into the component chamber. At the same time, a guide groove and a first valve located in the guide groove are also provided at the gas distribution hole. The first valve has a through hole, and a one-way membrane is provided in the through hole. The function of the above structure is that when it is necessary to separate the metering chamber and the component chamber, the gas distribution hole is sealed by the first valve. When it is necessary to connect the metering chamber and the component chamber, the gas distribution hole is connected through the through hole on the first valve. At this time, methanol gas can flow from the metering chamber into the component chamber through the one-way membrane, thereby realizing the function of gas transfer.

[0018] Preferably, the pressure-dividing component includes a pressure-dividing valve stem located in the component chamber and a pressure-dividing sealing end sleeved on the outer wall of the component chamber.

[0019] Preferably, the outer wall of the component cavity is provided with a sliding groove, and the inner wall of the pressure-dividing sealing end is provided with a slider that is slidably connected to the sliding groove.

[0020] The pressure-sharing component of this application includes a pressure-sharing valve stem and a pressure-sharing sealing end. The function of the pressure-sharing component is to balance the pressure and push the pressure-sharing sealing end to slide in the extension direction of the pressure-sharing chamber. The pressure-sharing sealing end drives the pressure-sharing valve stem to move in the component chamber. When in use, the pressure-sharing valve stem is pushed into the component chamber completely through the above steps to fill the component chamber. The component chamber is then separated from the metering chamber by the first valve. When it is necessary to transfer the gas in the metering chamber to the component chamber, the component chamber is connected to the metering chamber by the first valve. At this time, the gas will squeeze and push the pressure-sharing valve stem during the transfer process, causing the pressure-sharing valve stem and the pressure-sharing sealing end to move, thereby realizing the transfer of gas.

[0021] The application of the above-mentioned nitrogen methanol standard gas metering device in the preparation of nitrogen methanol standard gas includes the following steps: Step 1: Use a cylinder handling device to replace, evacuate, and dry the cylinder; pre-treat the cylinder to a predetermined pressure. Step 2: Heat and vaporize the liquid methanol using an organic vaporization device; Step 3: Connect the methanol standard gas metering device in nitrogen to the gas cylinder and place it on the weighing device to zero. After zeroing, connect the methanol standard gas metering device to the organic vaporization device in Step 2, open the gas inlet valve to inject methanol gas into the gas cylinder, and close the gas inlet valve and the gas cylinder valve when the weighing device reaches the predetermined weight. Separate the organic vaporization device from the methanol standard gas metering device and record the standard weight of the weighing device. Step 4: Adjust the methanol standard gas metering device in nitrogen according to the target weight. Slide the first valve to connect the one-way membrane with the gas separator. Adjust the pressure regulating device to force the gas in the metering chamber into the distribution chamber. The adjustment amount is the difference between the standard weight and the target weight. After adjustment, slide the first valve to separate the one-way membrane from the gas separator. Step 5: Connect the gas cylinder to the methanol standard gas metering device in nitrogen, inject all the gas in the metering chamber into the gas cylinder, and close the gas cylinder valve to complete the metered transfer of methanol gas into the gas cylinder. Step 6: Based on the mass of methanol gas transferred, assess the required mass of nitrogen, add nitrogen, and calculate the concentration.

[0022] Compared with the prior art, this application has the following technical effects: (1) The nitrogen methanol standard gas quantitative device provided in this application can accurately and quantitatively transfer methanol gas to the gas cylinder. It is simple to operate, highly accurate and can eliminate the influence of the injection device. (2) This application achieves quantitative measurement of gas through structures such as quantitative chamber and component chamber. At the same time, excess gas generated during the measurement process is stored in the component chamber and will not be discharged to the outside world, making it safe and environmentally friendly. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention.

[0024] Figure 2 This is a cross-sectional view of this application.

[0025] Figure 3 This is a longitudinal cross-sectional view of this application.

[0026] In the figure, there are: metering chamber 1, component chamber 2, pressure regulating component 3, metering valve 301, valve stem through hole 311, air guide component 312, air guide valve 313, pressure regulating sealing end 302, pressure dividing component 4, pressure dividing valve stem 401, pressure dividing sealing end 402, slide groove 403, slider 404, air dividing hole 5, guide groove 6, first valve component 7, through hole 701, one-way diaphragm 702, sealing ring 8, sealing gasket 9, and air inlet 10. Detailed Implementation

[0027] The present invention will be further described below with reference to embodiments.

[0028] Example 1: like Figure 1 As shown, a quantitative device for preparing methanol standard gas in nitrogen includes a quantitative chamber 1, a component chamber 2 connected to the quantitative chamber, a pressure regulating component 3 disposed in the quantitative chamber, and a pressure dividing component 4 disposed in the component chamber. Both ends of the quantitative chamber are provided with gas guides connected to the quantitative chamber, and gas guides are respectively provided with gas guide valves 313. The end of the gas guide located outside the quantitative chamber is provided with a sealing ring 8, and the outer wall of the quantitative chamber is provided with scale lines. like Figure 2 As shown, the pressure regulating component includes a metering valve 301 located in the metering chamber and a pressure regulating sealing end 302 sleeved on the outer wall of the metering chamber. The metering valve stem matches the metering chamber, and the sealing end is threadedly connected to the outer wall of the metering chamber. The inner wall of the sealing end is provided with an internal thread, and the outer wall of the metering chamber is provided with a limiting block. The limiting block is provided with an external thread that matches the internal thread on the inner wall of the sealing end. A sealing gasket 9 that fits against the outer wall of the metering chamber is provided at the opening of the sealing end. A valve stem through hole 311 is provided at the center of the metering valve stem, and a gas guide 312 is provided in the valve stem through hole. One end of the gas guide is located in the valve stem through hole, and the other end is located outside the valve stem through hole. A gas distribution hole 5 is provided on the metering chamber. The measuring chamber is provided with an air inlet 10, and the air distribution port is connected to the air inlet through a pipe. The measuring chamber is provided with a guide groove 6, and a first valve 7 is provided in the guide groove and slidably connected to the guide groove. The first valve is provided with a through hole 701 that matches the air distribution port. A one-way membrane 702 is provided in the through hole. Sliding the first valve can make the one-way membrane connect or separate from the air distribution port. The pressure dividing component includes a pressure dividing valve rod 401 located in the component chamber and a pressure dividing sealing end 402 sleeved on the outer wall of the component chamber. The outer wall of the component chamber is provided with a sliding groove 403, and the inner wall of the pressure dividing sealing end is provided with a slider 404 that slidably connects to the sliding groove. A sealing gasket that fits with the sliding groove is provided on the slider. like Figure 3 As shown, the first valve includes a ring and a flash disposed on the ring. The first valve is located in the guide groove and can rotate around the center of the first valve in the guide groove. The one-way membrane controls the gas to flow from the metering chamber into the component chamber. The application of a quantitative device for preparing methanol standard gas in nitrogen in the preparation of methanol standard gas in nitrogen includes the following steps: Step 1: Use a gas cylinder handling device to replace, evacuate, and dry the gas cylinder; Step 2: Heat and vaporize the liquid methanol using an organic vaporization device; Step 3: Connect the methanol standard gas metering device in nitrogen to the gas cylinder and place it on the weighing device to zero. After zeroing, connect the methanol standard gas metering device to the organic vaporization device in Step 2, open the gas inlet valve to inject methanol gas into the gas cylinder, and close the gas inlet valve and the gas cylinder valve when the weighing device reaches the predetermined weight. Separate the organic vaporization device from the methanol standard gas metering device and record the standard weight of the weighing device. Step 4: Adjust the methanol standard gas metering device in nitrogen according to the target weight. Slide the first valve to connect the one-way membrane with the gas separator. Adjust the pressure regulating device to force the gas in the metering chamber into the distribution chamber. The adjustment amount is the difference between the standard weight and the target weight. After adjustment, slide the first valve to separate the one-way membrane from the gas separator. Step 5: Connect the gas cylinder to the methanol standard gas metering device in nitrogen, inject all the gas in the metering chamber into the gas cylinder, and close the gas cylinder valve to complete the metered transfer of methanol gas into the gas cylinder.

[0029] Example 2: (Concentration approximately 102 μmol / mol, pressure 10 MPa) The application of a quantitative device for preparing methanol standard gas in nitrogen in the preparation of methanol standard gas in nitrogen includes the following steps: Step 1: The purity of the methanol liquid was determined by gas chromatography, Karl Fischer coulometric method and DSC method, and the purity was 99.95%. Before the gas was prepared, the gas cylinder was replaced, dried, evacuated and pre-saturated with high-purity nitrogen. Step 2: Use an organic vaporization device to heat and vaporize the liquid methanol into a metering ring; Step 3: Using the above-mentioned nitrogen-based methanol standard gas metering device, inject 0.64898g of methanol gas into the gas cylinder. Connect the nitrogen-based methanol standard gas metering device to the gas cylinder and place it on the weighing device to zero. After zeroing, connect the methanol standard gas metering device to the organic vaporization device in Step 2. Open the gas inlet valve to inject methanol gas into the gas cylinder. When the weighing device reaches the predetermined weight, close the gas inlet valve and the gas cylinder valve. Separate the organic vaporization device from the methanol standard gas metering device and record the standard weight of the weighing device. Step 4: Adjust the methanol standard gas metering device in nitrogen according to the target weight. Slide the first valve to connect the one-way membrane with the gas separator. Adjust the pressure regulating device to force the gas in the metering chamber into the distribution chamber. The adjustment amount is the difference between the standard weight and the target weight. After adjustment, slide the first valve to separate the one-way membrane from the gas separator. Step 5: Connect the gas cylinder to the methanol standard gas metering device in nitrogen, inject all the gas in the metering chamber into the gas cylinder, and close the gas cylinder valve to complete the metered transfer of methanol gas into the gas cylinder. Step 6: Add 573.944g of nitrogen gas to the gas cylinder to prepare a nitrogen-based methanol gas standard with a concentration of 987μmol / mol. Using a stepwise dilution method, add 100.575g of the 987μmol / mol nitrogen-based methanol gas standard and 875.829g of nitrogen gas to the gas cylinder to obtain a nitrogen-based methanol gas standard with a concentration of 102μmol / mol. After the preparation of the substance, the uniformity and stability of the nitrogen-based methanol gas standard under different pressures and times are observed by gas chromatography.

[0030] Example 3: (Concentration approximately 5.007 μmol / mol, pressure 10 MPa) The application of a nitrogen-based methanol standard gas metering device in the preparation of nitrogen-based methanol standard gas includes the following steps: Step 1: The purity of the methanol liquid was determined by gas chromatography, Karl Fischer coulometric method and DSC method, and the purity was 99.95%. Before the gas was prepared, the gas cylinder was replaced, dried, evacuated and pre-saturated with high-purity nitrogen. Step 2: Use an organic vaporization device to heat and vaporize the liquid methanol into a metering ring; Step 3: Using the above-mentioned nitrogen-based methanol standard gas metering device, inject 0.61224g of methanol gas into the gas cylinder. Connect the nitrogen-based methanol standard gas metering device to the gas cylinder and place it on the weighing device to zero. After zeroing, connect the methanol standard gas metering device to the organic vaporization device in Step 2. Open the gas inlet valve to inject methanol gas into the gas cylinder. When the weighing device reaches the predetermined weight, close the gas inlet valve and the gas cylinder valve. Separate the organic vaporization device from the methanol standard gas metering device and record the standard weight of the weighing device. Step 4: Adjust the methanol standard gas metering device in nitrogen according to the target weight. Slide the first valve to connect the one-way membrane with the gas separator. Adjust the pressure regulating device to force the gas in the metering chamber into the distribution chamber. The adjustment amount is the difference between the standard weight and the target weight. After adjustment, slide the first valve to separate the one-way membrane from the gas separator. Step 5: Connect the gas cylinder to the methanol standard gas metering device in nitrogen, inject all the gas in the metering chamber into the gas cylinder, and close the gas cylinder valve to complete the metered transfer of methanol gas into the gas cylinder. Step 6: Add 1011.730g of nitrogen gas to the gas cylinder to prepare a nitrogen-based methanol gas standard with a concentration of 529μmol / mol. Using a stepwise dilution method, add 9.856g of the 529μmol / mol nitrogen-based methanol gas standard and 1016.856g of nitrogen gas to the gas cylinder to obtain a nitrogen-based methanol gas standard with a concentration of 5.07μmol / mol. After preparation, the homogeneity and stability of the nitrogen-based methanol gas standard under different pressures and times are observed using gas chromatography.

[0031] Example 4: (Concentration approximately 1029 μmol / mol, pressure 5 MPa) The application of a nitrogen-based methanol standard gas metering device in the preparation of nitrogen-based methanol standard gas includes the following steps: Step 1: The purity of the methanol liquid was determined by gas chromatography, Karl Fischer coulometric method and DSC method, and the purity was 99.95%. Before the gas was prepared, the gas cylinder was replaced, dried, evacuated and pre-saturated with high-purity nitrogen. Step 2: Use an organic vaporization device to heat and vaporize the liquid methanol into a metering ring; Step 3: Using the above-mentioned nitrogen-based methanol standard gas metering device, inject 0.60211g of methanol gas into the gas cylinder. Connect the nitrogen-based methanol standard gas metering device to the gas cylinder and place it on the weighing device to zero. After zeroing, connect the methanol standard gas metering device to the organic vaporization device in Step 2. Open the gas inlet valve to inject methanol gas into the gas cylinder. When the weighing device reaches the predetermined weight, close the gas inlet valve and the gas cylinder valve. Separate the organic vaporization device from the methanol standard gas metering device and record the standard weight of the weighing device. Step 4: Adjust the methanol standard gas metering device in nitrogen according to the target weight. Slide the first valve to connect the one-way membrane with the gas separator. Adjust the pressure regulating device to force the gas in the metering chamber into the distribution chamber. The adjustment amount is the difference between the standard weight and the target weight. After adjustment, slide the first valve to separate the one-way membrane from the gas separator. Step 5: Connect the gas cylinder to the methanol standard gas metering device in nitrogen, inject all the gas in the metering chamber into the gas cylinder, and close the gas cylinder valve to complete the metered transfer of methanol gas into the gas cylinder. Step 6: Add 511.115g of nitrogen gas into the gas cylinder to prepare a nitrogen-methanol gas standard with a concentration of 1029μmol / mol. After the preparation of the substance, the uniformity and stability of the nitrogen-methanol gas standard under different pressures and times are observed by gas chromatography.

[0032] Comparative Example 1: Compared with Example 3, Comparative Example 1 did not use the nitrogen-methanol standard gas metering device of Example 1, but the other conditions were the same as those in Example 3.

[0033] Comparative Example 2: Compared with Example 4, Comparative Example 2 did not use the nitrogen-methanol standard gas metering device of Example 1, but the other conditions were the same as those in Example 4.

[0034] Comparative Example 3: Compared with Example 5, Comparative Example 3 did not use the nitrogen-methanol standard gas metering device of Example 1, but the other conditions were the same as those in Example 5.

[0035] Detection example The actual weight of methanol gas injected into the gas cylinders during the preparation of formaldehyde standard gas in nitrogen using the nitrogen-methanol standard gas quantitative device in Examples 2-4 and Comparative Examples 1-3 without the nitrogen-methanol standard gas quantitative device was measured. The methanol concentration in the gas cylinder was measured by gas chromatography, and the weight of methanol gas was calculated from the concentration. The actual weight of methanol gas injected into the gas cylinder was set as the actual weight, and the target weight of methanol gas to be injected into the gas cylinder was set as the target weight. The error value was calculated by the difference between the target weight and the actual weight. The test results are shown in Table 1. Table 1 Target Weight and Actual Weight of Methanol Gas Target weight (g) 0.64898 0.61224 0.60211 0.64898 0.61224 0.60211 Actual weight (g) 0.64899 0.61223 0.60209 0.63276 0.60014 0.59009 Error value 0.00001 0.00001 0.00002 0.01622 0.01210 0.01202 As shown in Table 1, in Examples 2-4, after using the nitrogen-based methanol standard gas metering device provided in this application, the error between the actual weight of methanol gas injected into the gas cylinder and the predetermined weight of methanol gas to be injected into the gas cylinder was within 0.00003, with an error range of less than three ten-thousandths. The error was extremely small, and the methanol gas could be accurately and quantitatively transferred into the gas cylinder. In contrast, Comparative Example 1, without using the nitrogen-based methanol standard gas metering device provided in this application, showed an actual error within 0.02, with an error range of less than two percent. Compared with this application, the accuracy was lower and the error was larger. Through the above comparison, it can be seen that using the nitrogen-based methanol standard gas metering device provided in this application can significantly improve the accuracy of methanol gas transfer into the gas cylinder, significantly reduce the error value generated during the transfer process, and accurately and quantitatively transfer methanol gas into the gas cylinder.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A device for preparing a quantitative standard gas of methanol in nitrogen, characterized in that, It includes a metering chamber (1), a component chamber (2) connected to the metering chamber, a pressure regulating component (3) installed in the metering chamber, and a pressure dividing component (4) installed in the component chamber. The metering chamber is provided with a gas dividing hole (5), which connects the metering chamber and the component chamber. The metering chamber is provided with a guide groove (6), and a first valve component (7) slidably connected to the guide groove is provided in the guide groove. The first valve component is provided with a through hole (701) matching the gas dividing hole, and a one-way membrane (702) is provided in the through hole. The one-way membrane controls the gas to flow from the metering chamber into the component chamber.

2. The apparatus for preparing a quantitative amount of a nitrogen standard gas containing methanol according to claim 1, wherein The pressure regulating component includes a metering valve stem (301) located in the metering chamber and a pressure regulating sealing end (302) sleeved on the outer wall of the metering chamber.

3. The apparatus for preparing a quantitative amount of a nitrogen standard gas containing methanol according to claim 2, wherein The metering valve stem is matched with the metering cavity, and the sealing end is threadedly connected to the outer wall of the metering cavity.

4. The apparatus for preparing a quantitative amount of a nitrogen standard gas containing methanol according to claim 2, wherein The metering valve stem is provided with a valve stem through hole (311), and a gas guide (312) is provided in the valve stem through hole. One end of the gas guide is located in the valve stem through hole, and the other end is located outside the valve stem through hole. A gas guide valve (313) is provided on the gas guide located outside the valve stem through hole.

5. The apparatus for preparing a quantitative amount of a nitrogen standard gas containing methanol according to claim 1, wherein The outer wall of the quantitative cavity is provided with graduation lines.

6. The apparatus for preparing a quantitative amount of a nitrogen standard gas containing methanol according to claim 1, wherein The pressure-dividing component includes a pressure-dividing valve stem (401) located in the component chamber and a pressure-dividing sealing end (402) sleeved on the outer wall of the component chamber.

7. The apparatus for preparing a quantitative amount of a nitrogen standard gas containing methanol according to claim 1, wherein The outer wall of the component chamber is provided with a sliding groove (403), and the inner wall of the pressure-dividing sealing end is provided with a slider (404) that is slidably connected to the sliding groove.

8. The application of a nitrogen methanol standard gas metering device according to any one of claims 1 to 7 in the preparation of nitrogen methanol standard gas, comprising the following steps: Step 1: Use a cylinder handling device to replace, evacuate, and dry the cylinder; pre-treat the cylinder to a predetermined pressure. Step 2: Heat and vaporize the liquid methanol using an organic vaporization device; Step 3: Connect the methanol standard gas metering device in nitrogen to the gas cylinder and place it on the weighing device to zero. After zeroing, connect the methanol standard gas metering device to the organic vaporization device in Step 2, open the gas inlet valve to inject methanol gas into the gas cylinder, and close the gas inlet valve and the gas cylinder valve when the weighing device reaches the predetermined weight. Separate the organic vaporization device from the methanol standard gas metering device and record the standard weight of the weighing device. Step 4: Adjust the methanol standard gas metering device in nitrogen according to the target weight. Slide the first valve to connect the one-way membrane with the gas separator. Adjust the pressure regulating device to force the gas in the metering chamber into the distribution chamber. The adjustment amount is the difference between the standard weight and the target weight. After adjustment, slide the first valve to separate the one-way membrane from the gas separator. Step 5: Connect the gas cylinder to the methanol standard gas metering device in nitrogen, inject all the gas in the metering chamber into the gas cylinder, and close the gas cylinder to complete the metered transfer of methanol gas into the gas cylinder. Step 6: Based on the mass of methanol gas transferred, assess the required mass of nitrogen, add nitrogen, and calculate the concentration.

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