Method for measuring proportion of single component in multi-component mixed gas

Abstract

The invention relates to a method for measuring the proportion of a single component in a multi-component mixed gas, which comprises the following steps: S1, the multi-component mixed gas is conveyed to a measuring gas chamber, and at least two flow meters with different principles are connected in series in the measuring gas chamber; s2, at least two parameters of each component in the multi-component mixed gas are obtained through the at least two flow meters in the measuring gas chamber; and S3, calculating by adopting calculation formulas corresponding to the two parameters to obtain the proportion of each component.

Description

Technical Field

[0001] This invention belongs to the technical field of gas analysis, specifically relating to a method for measuring the proportion of a certain component in a multi-component gas mixture. Background Technology

[0002] Currently, gas analysis methods mainly include gas chromatography, infrared spectroscopy, mass spectrometry, and electrochemical methods. However, these methods have problems such as large measurement equipment size, high price, inconvenience for continuous automatic detection, susceptibility to environmental interference, and inability to reuse the detected gas. They cannot meet the requirements for continuous online non-destructive monitoring in gas production processes.

[0003] Therefore, the method for measuring the proportion of a single component in a multi-component gas mixture needs to be optimized. Summary of the Invention

[0004] The purpose of this invention is to provide a new method for measuring the proportion of a single component in a multi-component gas mixture. The method is simple, highly automated, small in size, easy to maintain, and can assist in monitoring abnormal situations by setting alarm values, thus meeting the needs of process monitoring.

[0005] To achieve the above objectives, the present invention provides a method for measuring the proportion of a single component in a multi-component gas mixture, comprising: S1, the multi-component mixed gas is delivered to the measuring gas chamber, wherein at least two flow meters with different principles are connected in series in the measuring gas chamber; S2, in the measuring gas chamber, at least two parameters of each component in the multi-component mixture are obtained by the at least two flow meters; S3. Using the calculation formulas corresponding to the two parameters, the proportion of each component is calculated.

[0006] In some implementations, at least two flow meters are selected from two or more of thermal flow meters, volumetric flow meters, Coriolis mass flow meters, and laminar differential pressure flow meters.

[0007] In some embodiments, the flow meter is a thermal flow meter and a Coriolis mass flow meter.

[0008] In some embodiments, the flow meter is a thermal flow meter and a volumetric flow meter.

[0009] In some embodiments, the flow meter is a thermal flow meter and a laminar differential pressure flow meter.

[0010] In some embodiments, the flow meter is a Rioli mass flow meter and a laminar differential pressure flow meter.

[0011] In some embodiments, the flow meter is a thermal flow meter, a volumetric flow meter, or a Coriolis mass flow meter.

[0012] In some embodiments, the flow meter is a thermal flow meter, a volumetric flow meter, and a laminar differential pressure flow meter.

[0013] In some embodiments, the flow meter is a volumetric flow meter, a Coriolis mass flow meter, and a laminar differential pressure flow meter.

[0014] In some embodiments, the flow meter is a thermal flow meter, a volumetric flow meter, a Coriolis mass flow meter, and a laminar differential pressure flow meter.

[0015] In some implementations, the flow rate is controlled such that it is within 30% to 70% of the full capacity of each flow meter.

[0016] In some embodiments, the method further includes: data acquisition.

[0017] In some implementations, the method further includes: program calculation and output of results.

[0018] On the other hand, embodiments of this disclosure provide a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements a method for measuring the proportion of gas components as described in any embodiment of this disclosure.

[0019] Based on different principles, flow meters such as thermal, Coriolis, laminar, and volumetric flow meters measure flow based on specific heat, relative molecular mass, viscosity, and the ideal gas law, respectively. Therefore, flow meters calibrated with the same pure gas but based on different principles will yield results with discrepancies for the same gas mixture. In this invention, by connecting flow meters based on different principles in series, the flow indication deviation caused by their properties can be calculated. This deviation can then be used to measure the content of two-component gas mixtures using at least two flow meters, provided that the difference between the measurement results of the two flow meters is sufficiently significant. Furthermore, for multi-component gas mixtures, multiple flow meters can be connected in series, and the results can be analyzed to determine the proportion of each gas. This indirect method yields the proportion of a single component, resulting in a simple process, high automation, small size, easy maintenance, and the ability to set alarm values ​​to assist in monitoring abnormal conditions, thus meeting process monitoring needs. Attached Figure Description

[0020] Figure 1 A flowchart of the measurement method of the present invention is shown. Detailed Implementation

[0021] The following detailed description discusses exemplary embodiments. The specific embodiments included herein should not be construed as limiting the invention. Furthermore, while specific language may be used to describe features, actions, and / or structures in the embodiments described herein, the claims are not limited to the described features, actions, and / or structures. Those skilled in the art will understand that other embodiments, including improvements, are within the spirit and scope of the invention.

[0022] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] Currently, gas flow meters are widely used in various industries, and the accuracy of their flow detection and control is crucial for all applications. Mass flow measurement involves various principles and instruments, including thermal (thermal conductivity / temperature difference), volumetric (laminar pressure difference), Coriolis, and PVT volumetric flow meters. Combinations of different principles can be used to determine the composition of gas mixtures.

[0024] There are several different methods for measuring the mass flow rate of gases. Thermal mass flow meters, based on the principles of heat capacity and thermal conductivity, calculate the mass flow rate of a single substance or mixture with known gas properties (density) by measuring the temperature difference of the measuring device. They generally output volumetric flow rate, but can also output mass flow rate. Coriolis mass flow meters derive mass and density from vibration frequency and deflection, independent of the substance's properties, and output mass flow rate. Laminar differential pressure mass flow meters are precision flow measurement instruments designed based on Hagen-Poiseuille's law. Their technical principle mainly relies on the flow characteristics of fluids in laminar flow conditions, where the fluid moves in a layered manner in the pipe, with each particle moving smoothly in a straight line parallel to the pipe axis. In this case, the volumetric flow rate of the fluid has a linear relationship with the pressure difference across the pipe. Pressure and temperature corrections are applied to this volumetric flow rate to obtain the standard volumetric flow rate and mass flow rate. PVT (Positive Temperature Flow) meters, for containers of a certain volume, calculate the number of moles of gas within the container volume using the ideal gas law or other more precise equations based on pressure changes, and employing temperature corrections.

[0025] In summary, thermal mass flow meters reflect the heat transfer properties of gases, Coriolis mass flow meters reflect gas density and mass flow rate, laminar differential pressure mass flow meters reflect the gas viscosity coefficient, and PVT volumetric mass flow meters reflect the gas molar flow rate. Using a multi-principle system combining several measurement methods to calculate the composition of gases is feasible and meaningful in certain applications.

[0026] Thermal mass flow meters calculate the mass flow rate of a single substance or mixture with known gas properties by utilizing the temperature difference between the two ends of the gas flow through the measuring device (i.e., the flow meter) based on the principles of heat capacity and thermal conductivity. They typically output the volumetric flow rate under standard conditions. The calculation formula is as follows: ,in V is the density of the medium under operating conditions, K is the flow velocity, Q is the balance coefficient, Q is the heating amount (related to specific heat and structure), and ΔT is the temperature difference between the two ends of the flow meter.

[0027] The Coriolis mass flow meter uses pipe vibration, specifically a thin-walled measuring tube fixed at both ends, to excite the fluid flowing inside the tube at the midpoint at a frequency that is either the resonant frequency or close to the resonant frequency (or its higher harmonic frequencies). This generates a Coriolis force, causing the two halves of the measuring tube to flex in opposite directions before and after the midpoint. The amount of flex is detected using optical or electromagnetic methods to determine the mass flow rate. Since the fluid density affects the vibration frequency of the measuring tube, and density and frequency have a fixed relationship, the fluid density can also be measured.

[0028] The core working principle of a laminar flow differential pressure flowmeter is the linear relationship between pressure drop and flow rate: Under laminar flow conditions, the pressure drop (ΔP) of a fluid passing through a straight pipe section is directly proportional to the flow rate (Q), fluid viscosity (μ), and the length of the pipe (L), and inversely proportional to the fourth power of the pipe's inner diameter (d), following the Hagen-Poiseuille equation: Q = πr 4 ΔP / (8μL) means that the flow rate is proportional to the pressure drop, and the measurement result is related to the gas viscosity coefficient.

[0029] For a container of a certain volume, the PVT (Polypositional Temperature Variable) system calculates the number of moles of gas in the container by using the ideal gas law or other more precise equations based on pressure changes, and employing temperature corrections. The real-time molar flow rate can be calculated using the pressure change rate.

[0030] Based on the differences in heat transfer properties, density, and viscosity of each component in a multi-component gas, the proportion of a single component can be obtained by combining its calculation formula with the PVT volumetric calculation formula. It is important to note that the gas properties must have significant differences to avoid insufficient flowmeter accuracy leading to inaccurate conclusions. If there are many gas components, and calculation cannot be completed based on a single different property, multiple flowmeters with different properties can be connected in series, and multiple formulas can be combined. When the components in a multi-component gas have almost identical properties, a flowmeter with this property can replace the PVT volumetric method.

[0031] It should be understood that the accuracy range of flow meters is usually between 0.5% and 2%. If the deviation between two flow meters is less than 5%, the accuracy cannot be guaranteed due to the limitation of measurement accuracy.

[0032] For example, the total D abundance was calculated using an H2-D2 mixture. The calculation showed that the difference between the thermal flowmeter values ​​for pure H2 and D2 was 1.2%, which is negligible, and the flow rate of the mixture obtained through the thermal flowmeter can be used as the molar flow rate. In other words, the gas-thermal effect of H2 and D2 is relatively small. However, their relative molecular masses differ by a factor of two; therefore, the component proportions can be analyzed by selecting two flowmeters with sufficiently large differences in measurement results. For example, due to accuracy limitations, the deviation between the flowmeters needs to be greater than 10%.

[0033] In the analysis of the H2-D2 mixture, a Coriolis mass flow meter and a thermal mass flow meter were connected in series. The output values ​​of both were standardized by a host computer. Real-time calculation of D abundance is performed. The Coriolis mass flow meter outputs the mass flow rate, while the thermal mass flow meter outputs the volumetric flow rate under standard conditions. Dividing the two gives the density of the mixture under standard conditions. Let H2 be the density under standard conditions. According to... , , , , The abundance of deuterium can be obtained. .

[0034] It should be noted that the gas flow rate and pressure to be measured must be within the operating range of both mass flow meters, and should be within 30% to 70% of the full scale of the mass flow meters. The real-time D abundance can be obtained by calculation.

[0035] A calibrated Coriolis mass flow meter is connected in series with a thermal mass flow controller. The gas supply is connected to the front end of the Coriolis mass flow meter, and the rear end of the thermal mass flow controller is connected to a hydrogen storage tank.

[0036] The flow rate is controlled using a thermal mass flow controller. Before starting the test, ensure that the hydrogen storage tank has sufficient volume.

[0037] Set the control flow rate to be within the range of 30% to 70% of the full capacity of the two flow meters.

[0038] Read real-time traffic and calculate real-time D abundance.

[0039] The cumulative flow is obtained by accumulating real-time flow, and the average D abundance can be obtained by substituting it into the above formula.

[0040] Therefore, the data obtained by the thermal flow meter is the standard volumetric flow rate; the Coriolis flow meter can obtain the mass flow rate, indicating that the airflow density can be obtained by connecting two flow meters in series. For H2 and D2, the difference in their relative molecular masses is large enough that the component proportion can be calculated.

[0041] It should be noted that the methods described above in this application can be implemented as computer software programs. For example, embodiments of this application include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for performing the methods shown in the flowchart. When the computer program is executed by a processor, it performs the functions defined in the methods of the embodiments of this disclosure.

[0042] The computer-readable medium of this application may be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, and portable compact disk read-only memory (CD-ROM). ROM, optical storage devices, magnetic storage devices, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wires, optical fibers, RF (radio frequency), etc., or any suitable combination thereof.

[0043] The aforementioned computer-readable medium may be included in the aforementioned electronic device; or it may exist independently and not assembled into the electronic device.

[0044] The present invention will be described in more detail below through embodiments. It should be understood that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art or in accordance with the product manual.

[0045] Example Instruments and models BronkHost mass flow meter models: M12, M13; measuring range: 1-25 g / h; measurement accuracy: 0.5%FS. Horiba S600 thermal mass flow meter model; measuring range: 0~5 SLM; measurement accuracy: 1%FS Experimental testing plan: Connect the mass flow meter to the PLC; then, directly read the instantaneous flow value via the Profibus DP interface of the mass flow meter through communication.

[0046] System solution: Two flow meters are connected in series. The gas supply pressure meets the differential pressure requirements of the flow meters. The following measurement data is obtained using H2+D2 with different known components:

[0047] Measured and calculated values:

[0048] Although this application has been described with reference to its specific exemplary embodiments, many different variations, modifications, etc. will become apparent to those skilled in the art.

[0049] By studying the accompanying drawings, the disclosure, and the appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments in practicing this application.

Claims

1. A method for measuring the proportion of a single component in a multi-component gas mixture, comprising: S1, the multi-component mixed gas is delivered to the measuring gas chamber, wherein at least two flow meters with different principles are connected in series in the measuring gas chamber; S2, in the measuring gas chamber, at least two parameters of each component in the multi-component mixture are obtained by the at least two flow meters; S3. The proportion of each component is calculated by combining the calculation formulas corresponding to the two parameters.

2. The method according to claim 1, wherein, At least two flow meters are selected from two or more of the following: thermal flow meters, volumetric flow meters, Coriolis mass flow meters, and laminar differential pressure flow meters.

3. The method according to claim 1 or 2, wherein, The flow meter is Thermal flow meters and Coriolis mass flow meters, or Thermal flow meters and volumetric flow meters, or Thermal flow meters and laminar differential pressure flow meters, or Volumetric flow meters and Coriolis mass flow meters, or Volumetric flow meters and laminar differential pressure flow meters, or Coriolis mass flow meter and laminar differential pressure flow meter.

4. The method according to claim 1 or 2, wherein, The flow meter is Thermal flow meters, volumetric flow meters, and Coriolis mass flow meters, or Thermal flow meters, volumetric flow meters, and laminar differential pressure flow meters, or Volumetric flow meters, Coriolis mass flow meters, and laminar differential pressure flow meters.

5. The method according to claim 1 or 2, wherein, The flow meters are thermal flow meters, volumetric flow meters, Coriolis mass flow meters, and laminar differential pressure flow meters.

6. The method according to any one of claims 1 to 5, wherein, The flow rate is controlled to ensure that it is within 30% to 70% of the full capacity of each flow meter.

7. The method according to any one of claims 1 to 6, wherein, The method further includes: data acquisition.

8. The method according to any one of claims 1 to 7, wherein, The method further includes: program calculation and output of results.

9. A computer storage medium storing computer instructions, said computer instructions being used to cause a processor to execute the method of any one of claims 1 to 8.

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