Hydrogen sampling steel cylinder purification system

Abstract

The utility model discloses a hydrogen sampling steel cylinder purification system which at least comprises a vacuum unit which comprises a molecular pump and a mechanical pump which are connected in series and is used for vacuumizing a sampling steel cylinder in a low-pressure state; the mechanical pump is connected with a ventilation pipeline of the sampling steel cylinder through the bypass valve and is used for vacuumizing the sampling steel cylinder in a high-pressure state; the heating unit comprises a heater and a temperature controller, the heater covers the outer wall of the sampling steel cylinder, and the temperature controller is used for adjusting the heating temperature of the heater. Through the synergistic effect of the vacuum unit and the heating unit, a sampling steel cylinder can be thoroughly purified, a hydrogen sample is prevented from being interfered by impurities adsorbed in the steel cylinder, the hydrogen sample is ensured to have representativeness, and a guarantee is provided for accurately measuring the hydrogen quality.

Description

Technical Field

[0001] The utility model relates to the technical field of gas sampling, in particular to a hydrogen sampling cylinder purification system. Background Art

[0002] With the rapid development of hydrogen energy technology in recent years, hydrogen quality has a significant impact on the performance and lifespan of fuel cell engines. During daily use, hydrogen must be sampled and tested using steel cylinders. Sampling cylinders are reused and require purification to remove highly adsorbable impurities (such as formic acid, formaldehyde, and ammonia) from the cylinders during the previous sampling. This ensures compliance with the requirements of GB / T 37244, "Hydrogen for Proton Exchange Membrane Fuel Cell Vehicles," prevents interference from adsorbed impurities in hydrogen samples, keeps them free of contamination, and ensures representative hydrogen samples, ensuring accurate hydrogen quality measurement.

[0003] Chinese patent CN219038532U discloses a high-pressure hydrogen sampling device for a hydrogen refueling station, comprising a hydrogenation port, a venting quick connector, a nitrogen protection quick connector, a high-pressure pressure regulating valve, a proportional unloading valve, and a series of ball valves. The hydrogenation port is tightly connected to the hydrogenation gun and is respectively connected to the left and right trunnion ball valves. The left trunnion ball valve is a sampling switch valve, and the right trunnion ball valve is a purge switch valve. The upper left of the trunnion ball valve is connected to a high-pressure pressure regulating valve, and the high-pressure pressure regulating valve is respectively connected to a proportional unloading valve and a series of ball valves. The proportional unloading valve is connected to a nitrogen protection quick connector. One of the paths of the series of ball valves is connected to a sulfur-passivated coated cylinder, and the other paths are connected to an 8L sampling bottle through a cylinder connector. The right trunnion ball valve is connected to a venting quick connector through a filter, and the venting quick connector is connected to the vent port of the hydrogenator. This solution can effectively carry out high-pressure hydrogen sampling, meet the sample volume required for hydrogen testing, and avoid sampling being limited due to high-pressure safety factors, resulting in a lack of hydrogen quality monitoring.

[0004] This type of solution typically involves purifying sampling cylinders through nitrogen purging combined with hydrogen replacement. This ensures sampling safety while also providing a certain degree of cylinder purification. However, this approach is limited to pre-use treatment of sampling cylinders. It cannot completely purify the cylinders of highly adsorbable impurities, and for reusable cylinders, it cannot meet the requirements of GB / T 37244.

[0005] Therefore, there is an urgent need for a hydrogen sampling cylinder purification system that can effectively ensure the accuracy and representativeness of hydrogen sampling cylinders during reuse and sampling.

[0006] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Utility Model Content

[0007] The purpose of the utility model is to provide a hydrogen sampling cylinder purification system, which can thoroughly purify the sampling cylinder through the coordinated action of the vacuum unit and the heating unit, thereby preventing the hydrogen sample from being interfered with by impurities adsorbed in the cylinder, ensuring that the hydrogen sample is representative, and providing a guarantee for accurately measuring the quality of hydrogen.

[0008] To achieve the above-mentioned purpose, the utility model provides a hydrogen sampling cylinder purification system, which at least includes: a vacuum unit, which includes a molecular pump and a mechanical pump arranged in series, and is used to vacuum the sampling cylinder under a low-pressure state; the mechanical pump is connected to the ventilation pipeline of the sampling cylinder through a bypass valve, and is used to vacuum the sampling cylinder under a high-pressure state; a heating unit, which includes a heater and a temperature controller, the heater is coated on the outer wall of the sampling cylinder, and the temperature controller is used to adjust the heating temperature of the heater.

[0009] Furthermore, in the above technical solution, a high vacuum valve is provided on the pipeline upstream of the molecular pump, and a low vacuum valve is provided on the pipeline downstream of the molecular pump. A vacuum gauge may also be provided on the pipeline upstream of the molecular pump.

[0010] Furthermore, in the above technical solution, a cylinder valve is provided on the ventilation pipe of the sampling cylinder to control the inflation and deinflating of the sampling cylinder.

[0011] Furthermore, in the above technical solution, the purification system of the present invention further includes an air intake unit comprising a nitrogen intake line connected to a cylinder valve for filling the sampling cylinder with nitrogen. Furthermore, in the above technical solution, the nitrogen intake line is sequentially provided with a nitrogen cylinder, a flowmeter, a filter for obtaining a nitrogen impurity content of less than 1 ppb, and an intake valve. A vent valve and a check valve may be provided on the intake line between the intake valve and the cylinder valve.

[0012] Furthermore, in the above technical solution, the purification system of the present invention is configured to, after the sampling cylinder is filled with filtered high-pressure nitrogen, perform a vacuum treatment under heating conditions to remove impurities adsorbed within the sampling cylinder. All internal surfaces of the piping and valves in the purification system are preferably passivated.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1) The purification system of the utility model can complete the purification treatment of the hydrogen sampling cylinder for proton exchange membrane fuel cell vehicles, realize the reuse of the sampling cylinder and improve the sampling accuracy; the utility model fills the sampling cylinder with filtered high-pressure nitrogen and processes it under high vacuum conditions (the vacuum degree can reach 1×10 -4 Pa) method to purify the sampling cylinder, which can completely remove the impurities with strong adsorption capacity in the sampling cylinder;

[0015] 2) The utility model connects the mechanical pump to the ventilation pipe of the sampling cylinder through a bypass valve. In the initial stage of vacuuming (i.e., the sampling cylinder is in a high pressure state), only the mechanical pump is used for vacuuming. When the pressure in the cylinder drops to a low pressure state, the bypass valve can be controlled to close and switch to the vacuuming process of "molecular pump + mechanical pump". In this way, the vacuum degree in the sampling cylinder can be achieved to 1×10 -4 Pa, and can also avoid the damage of high pressure to the molecular pump;

[0016] 3) The utility model provides a filter on the air intake line of the air intake unit, so that the impurity content of nitrogen can be lower than 1ppb, thereby further ensuring the purification effect of the sampling cylinder.

[0017] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a connection diagram of the hydrogen sampling cylinder purification system of the utility model.

[0019] Description of main reference numerals:

[0020] 1-Nitrogen cylinder, 2-Flow meter, 3-Filter, 4-Inlet valve, 5-Vent valve, 6-Check valve, 7-Cylinder valve, 8-Thermostat, 9-Heater, 10-Sampling cylinder, 11-Bypass valve, 12-Vacuum gauge, 13-High vacuum valve, 14-Molecular pump, 15-Rough vacuum valve, 16-Mechanical pump. DETAILED DESCRIPTION

[0021] The specific implementation of the present invention will be described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation.

[0022] Unless expressly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising” will be understood to include the stated elements or components but not to exclude other elements or components.

[0023] In this document, for ease of description, spatially relative terms such as "below," "beneath," "down," "above," "above," etc. may be used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that the spatially relative terms are intended to encompass different orientations of an object in use or operation in addition to the orientation depicted in the drawings. For example, if the object in the figure is turned over, the element described as being "below" or "below" other elements or features will be oriented "above" the element or feature. Therefore, the exemplary term "below" can include both below and above directions. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatially relative terms used herein should be interpreted accordingly.

[0024] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit specific positions or relative relationships. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable with each other.

[0025] like Figure 1 As shown, in order to ensure the reusability of the hydrogen sampling cylinder 10 and the accuracy and representativeness of hydrogen sampling, the present invention provides a hydrogen sampling cylinder purification system. The purification system can purify the hydrogen sampling cylinders for proton exchange membrane fuel cell vehicles, thereby achieving the reuse of the sampling cylinders and the sampling accuracy. In the present invention, the sampling cylinder 10 can be filled with filtered high-pressure nitrogen and subjected to high vacuum treatment (vacuum degree can reach 1×10 -4 The sampling cylinder 10 is purified in a manner of (100 Pa). The purification system is provided with at least a vacuum unit and a heating unit. The vacuum unit includes at least a molecular pump 14 and a mechanical pump 16 arranged in series, which are used to vacuum the sampling cylinder in a low-pressure state (that is, the mechanical pump 16 is used to reduce the gas pressure in the sampling cylinder 10 to 1-10 Pa). The mechanical pump 16 is connected to the ventilation pipe of the sampling cylinder 10 through a bypass valve 11, and is used to vacuum the sampling cylinder in a high-pressure state (that is, the pressure state of 1-6 MPa after being filled with nitrogen). The heating unit includes a heater 9 and a temperature controller 8. The heater 9 is coated on the outer wall of the sampling cylinder 10 (it can be wrapped with a heating belt or other heating facilities). The temperature controller 8 is used to adjust the heating temperature of the heater 9. The heater temperature can be set within the range of 60-120°C.

[0026] By adopting the above-mentioned technical solution of the present invention, the sampling cylinder can be thoroughly purified by filling it with high-pressure nitrogen and performing high-vacuum treatment under heating conditions, and impurities such as formic acid, formaldehyde and ammonia with strong adsorption capacity can be removed to avoid interference from adsorbed impurities when using the sampling cylinder for hydrogen sampling. It should be noted here that the present invention connects the mechanical pump to the ventilation pipeline of the sampling cylinder through a bypass valve. In the initial stage of vacuuming (that is, the stage when the sampling cylinder is just filled with nitrogen and the air pressure is relatively high), only the mechanical pump can be used for vacuuming. When the air pressure in the cylinder drops to the range of 1 to 10 Pa, the bypass valve can be controlled to close and switch to the vacuuming process of "molecular pump + mechanical pump". In this way, not only can the vacuum degree in the sampling cylinder reach 1×10 -4 Pa, and can also avoid the damage of high pressure to the molecular pump.

[0027] Further Figure 1 As shown, a high vacuum valve 13 is provided on the pipeline upstream of the molecular pump 14, and a low vacuum valve 15 is provided on the pipeline downstream of the molecular pump 14. A vacuum gauge 12 is also provided on the upstream pipeline of the molecular pump 14. A gas cylinder valve 7 is provided on the ventilation pipeline of the sampling cylinder 10, which is used to control the inflation and degassing of the sampling cylinder 10. The ventilation pipeline for vacuuming of the utility model is actually a two-way design, one of which is connected in series in sequence with the gas cylinder valve 7, vacuum gauge 12, high vacuum valve 13, molecular pump 14, low vacuum valve 15 and mechanical pump 16, and is used to vacuum under low pressure; the other is connected in series with the gas cylinder valve 7, bypass valve 11 and mechanical pump 16, and is used to vacuum under high pressure, and the two ways are switched for use.

[0028] Further Figure 1 As shown, the purification system of the present invention also includes an air intake unit, which is provided with a nitrogen air intake pipeline, and the nitrogen air intake pipeline is connected to the gas cylinder valve 7, which is used to fill the sampling cylinder 10 with nitrogen (the pressure range of the nitrogen can be 1 to 6 MPa). The nitrogen air intake pipeline is provided with a nitrogen cylinder 1, a flow meter 2, a filter 3 and an air intake valve 4 in sequence. Among them, the flow meter 2 preferably adopts a gas mass flow controller MFC; the filter 3 is a gas filter, which can adopt room temperature catalytic technology to obtain high-purity nitrogen by combining chemical reaction and physical adsorption, so that the impurity content of the nitrogen is less than 1 ppb, which can ensure the purification effect of the sampling cylinder. Furthermore, a vent valve 5 and a one-way valve 6 are provided on the air intake pipeline between the air intake valve 4 and the gas cylinder valve 7, which can be used to vent the gas in the air intake pipeline during nitrogen replacement.

[0029] This utility model uses an air inlet unit to fill the sampling cylinder with filtered, high-pressure nitrogen. The heated cylinder is then subjected to a high-vacuum treatment through the synergistic action of a heating unit and a vacuum unit, thereby purifying the cylinder and effectively ensuring its purification. All piping and valve internal surfaces in the purification system are passivated to prevent the adsorption of impurity molecules within the system.

[0030] The purification process of the utility model is described in detail below:

[0031] Before starting the purification process of the sampling cylinder 10, the air inlet pipe of the air inlet unit is replaced with high-purity nitrogen. The high-purity nitrogen cylinder 1, flow meter 2, air inlet valve 4 and vent valve 5 are opened in sequence. The purity of the nitrogen purified by the filter 3 can reach 99.99999%. The gas flow rate is 1 to 5 liters / minute, and the gas replacement time is 30 to 60 minutes. The heating unit and vacuum unit are started to purify the sampling cylinder and the ventilation pipe, and the impurity molecules adsorbed on the inner surface are desorbed. The heater temperature is set in the range of 60 to 120 ° C, and the vacuum degree is higher than 1×10 -4 Pa, the purification time is 30 to 60 minutes; open the air intake unit and the heating unit, open the flow meter 2, the air intake valve 4, and the cylinder valve 7, and fill the sampling cylinder 10 with nitrogen. The pressure range of the nitrogen is 1 to 6 MPa. Close the air intake unit and open the vacuum unit. During the vacuuming process, first enable the bypass mechanical pump to vacuum alone until the pressure in the sampling cylinder 10 drops to the low pressure range of 1 to 10 Pa, then close the bypass valve 11, enable the molecular pump 14 and the mechanical pump 16 to vacuum together until the vacuum degree inside the sampling cylinder 10 reaches 1×10 -4 Pa, the temperature of the sampling cylinder is between 60 and 120 ° C, and a purification process is completed; repeat the above purification process 3 to 10 times to complete the purification of the sampling cylinder.

[0032] The foregoing descriptions of specific exemplary embodiments of the present invention are for illustrative and illustrative purposes. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations are possible based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize the various exemplary embodiments of the present invention and various options and variations. Any simple modifications, equivalent variations, and modifications made to the above exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A hydrogen sampling cylinder purification system, characterized in that: include: The vacuum unit includes a molecular pump and a mechanical pump arranged in series, and is used to evacuate the sampling cylinder under low pressure; the mechanical pump is connected to the ventilation line of the sampling cylinder through a bypass valve, and is used to evacuate the sampling cylinder under high pressure; The heating unit comprises a heater and a temperature controller. The heater is coated on the outer wall of the sampling cylinder, and the temperature controller is used to adjust the heating temperature of the heater.

2. The hydrogen sampling cylinder purification system according to claim 1, characterized in that: A high vacuum valve is provided on the upstream of the pipeline of the molecular pump, and a low vacuum valve is provided on the downstream of the pipeline of the molecular pump.

3. The hydrogen sampling cylinder purification system according to claim 2, characterized in that: The upstream pipeline of the molecular pump is provided with a vacuum gauge.

4. The hydrogen sampling cylinder purification system according to claim 1, characterized in that: A gas cylinder valve is provided on the ventilation pipeline of the sampling cylinder for controlling the inflation and deinflating of the sampling cylinder.

5. The hydrogen sampling cylinder purification system according to claim 4, characterized in that: The purification system also includes: The air intake unit includes a nitrogen air intake pipeline connected to the gas cylinder valve and is used to fill the sampling cylinder with nitrogen.

6. The hydrogen sampling cylinder purification system according to claim 5, characterized in that: The nitrogen inlet pipeline is sequentially provided with a nitrogen bottle, a flow meter, a filter for obtaining nitrogen with an impurity content lower than 1 ppb, and an inlet valve.

7. The hydrogen sampling cylinder purification system according to claim 6, characterized in that: A vent valve and a one-way valve are provided on the air intake pipeline between the air intake valve and the gas cylinder valve.

8. The hydrogen sampling cylinder purification system according to claim 1, characterized in that: The purification system is used to perform vacuum treatment under heating conditions after the sampling cylinder is filled with filtered high-pressure nitrogen to remove impurities adsorbed in the sampling cylinder.

9. The hydrogen sampling cylinder purification system according to claim 1, characterized in that: All pipelines and valve internal surfaces of the purification system are passivated surfaces.

Images