System and method for supplying acetylene

Abstract

To provide a system and method for stably supplying acetylene.SOLUTION: The system comprises at least one acetylene storage apparatus 1, 2, a detection module 5, a gas dilution module 4 and a gas supply regulating module. By mixing a feedstock stream outputted from the acetylene storage apparatus with a diluting gas in a specific ratio, a photoionization detector is successfully used to detect a solvent content in the feedstock stream. This real-time and continuous detection method ensures a stable supply of acetylene to a downstream process.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application is in the field of element content measurement and relates to a system and method for supplying acetylene. In particular, this application relates to a system and method for providing a stable and continuous supply of acetylene with a controllable solvent content. [Background technology]

[0002] As an important industrial gas, acetylene has a wide range of applications in the fields of cutting, welding, and heat treatment. Take the field of low-pressure carburization for example, which involves carburizing at very low pressure (7-13 mbar). The workpiece is placed in a medium containing activated carbon atoms at a certain temperature so that the carbon atoms penetrate into the surface layer of the workpiece. This allows the surface layer of the workpiece to acquire sufficiently high hardness, wear resistance, and fatigue resistance. Acetylene is the most suitable carburizing medium for the low-pressure carburization process.

[0003] Acetylene has a very wide flammability range. Its lower flammability limit (LFL) is 2.4%, while its upper flammability limit (UFL) is 83%. Due to its thermal instability, acetylene storage presents many challenges. For this reason, acetylene is typically stored in specially designed acetylene cylinders. The interior of an acetylene cylinder is filled with a porous packing medium with a solvent dispersed within it. Acetone, dimethylformamide (DMF), and N-methylpyrrolidone (NMP) are common solvents for dissolving acetylene due to their ability to solubilize it. These solvents can absorb large amounts of acetylene at relatively low pressures, making it possible to place acetylene in low-pressure cylinders. The solvent is dispersed within and around the pores of the porous packing medium.

[0004] Due to the health risks associated with DMF and NMP, acetone is currently the primary solvent commonly used in China. Acetone's boiling point is only 56.53°C, making it highly volatile. Acetone vapor can escape from acetylene cylinders, so it is inevitably delivered along with the acetylene. As the acetylene in the cylinder is gradually consumed, the proportion of acetone mixed into the acetylene becomes very high. Thus, acetone becomes a contaminant in the acetylene, ultimately reducing the deposition rate and film uniformity.

[0005] Due to the lack of an effective method for monitoring solvent content in real time, users often rely on experience and replace acetylene cylinders with new ones when the residual acetylene pressure in the cylinder drops to an empirical value. For acetone-acetylene cylinders, it is generally recommended to replace the cylinder when the cylinder pressure reaches approximately 6 bar to prevent excessive acetone solvent from entering downstream processes. However, because many factors affect the solvent content in acetylene cylinders, the aforementioned method for estimating the residual acetylene gas pressure is not sufficiently accurate. If the estimated value is too low, a large amount of solvent will inevitably enter the downstream process, which is undesirable. If the estimated value is too high, frequent replacement of acetylene cylinders is extremely uneconomical.

[0006] U.S. Patent No. 5,949,623 discloses a method for supplying high-purity acetylene to a processing device. The method includes providing an adsorption bed containing an adsorption medium, the adsorption medium including at least a first adsorption medium capable of selectively removing water, a second adsorption medium capable of selectively removing solvent, and a third adsorption medium capable of selectively removing carbon dioxide. In this way, the concentrations of water, solvent, and carbon dioxide in the acetylene discharged from the storage vessel are reduced to provide high-purity acetylene. However, a drawback of this method is that a very large amount of energy must be consumed to regenerate the adsorption medium. Furthermore, the solvent must be removed in the process of regenerating the adsorption medium, and further solvent must be consumed in the subsequent recharging process.

[0007] The Chinese Patent Application for Invention (Patent Document 2) discloses a system and method for supplying acetylene to an acetylene-using device. The device uses GC-FID (Gas Chromatography-Flame Ionization Detector) or Fourier Transform Infrared Spectroscopy (FTIR) to detect the concentration of solvents in the acetylene. However, GC-FID is a non-continuous measurement method, so continuous real-time measurement results cannot be obtained. Meanwhile, FTIR has very strict operating conditions and is very expensive. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent No. 8,398,747B [Patent Document 2] Chinese Patent Application Publication No. 113719748A Summary of the Invention [Problem to be solved by the invention]

[0009] In view of the above, the applicant wishes to research a system and method for supplying acetylene that can monitor the solvent content in an acetylene cylinder in real time to accurately indicate the acetylene purity or solvent content in the acetylene cylinder, thereby overcoming the drawbacks of the prior art. [Means for solving the problem]

[0010] In order to solve the above technical problems, the applicant wishes to find a real-time, continuous and easily implemented method for detecting the solvent content in an acetylene cylinder in order to realize a stable and reliable supply of acetylene.

[0011] A first aspect of the present application is a system for supplying acetylene, comprising: at least one acetylene storage unit providing a feed stream comprising acetylene and a solvent; a gas dilution module for uniformly mixing a portion of the feed stream with a dilution gas according to a certain ratio to obtain a gas mixture to be measured, the gas dilution module including a pressure equalization device, a filtration device, a flow rate adjustment device, and a premixing device; a detection module including a photoionization detector and a control unit, wherein the mixed gas to be measured enters the photoionization detector and is ionized by excitation to generate a measurement signal, and the control unit is configured to calculate a solvent concentration based on the measurement signal from the photoionization detector, compare it with a solvent concentration preset value, and output a control signal; a gas supply regulation module including a solenoid valve, a pressure transmitter, and a flow sensor, all of which are electrically connected to a control unit, wherein the solenoid valve is used to exchange each acetylene storage device, the pressure transmitter is used to detect the pressure of the feed stream output by each acetylene storage device, and the flow sensor is used to detect the flow rate of the feed stream supplied to an acetylene-using device; The present invention discloses a system comprising:

[0012] Additionally, the gas supply regulation module is used to change out the acetylene storage device when the solvent concentration in the feed stream exceeds a preset value or when the pressure of the feed stream is lower than a preset pressure.

[0013] The preset value of the solvent concentration can be set according to the requirements of the downstream process and can vary within the range of several hundred to several thousand ppm, but no limitation is imposed in the embodiments of the present application.

[0014] Furthermore, in the gas dilution module, the volume ratio of the dilution gas to the portion of the feed stream is 50 or more, preferably 60 or more.

[0015] Furthermore, the acetylene storage device is an acetylene cylinder or a set of acetylene cylinders.

[0016] Additionally, the pressure equalization device within the gas dilution module includes a first pressure regulator that adjusts the pressure of a portion of the feed stream and a second pressure regulator that adjusts the pressure of the dilution gas.

[0017] Additionally, the first pressure regulator reduces the pressure of the portion of the feed stream entering the gas dilution module to less than 0.5 kg.

[0018] Additionally, the second pressure regulator reduces the pressure of the dilution gas entering the gas dilution module to less than 0.5 kg.

[0019] Furthermore, a linear characteristic equation of acetone concentration versus response voltage is stored in the control unit.

[0020] Furthermore, the filter in the gas dilution module may be a sintered filter. Preferably, the filter is used to filter particulate impurities in the raw gas.

[0021] Furthermore, the flow regulators in the gas dilution module include a first flow regulator for regulating the flow rate of a portion of the feed stream and a second flow regulator for regulating the flow rate of the dilution gas, and preferably, the flow regulators are mass flow controllers.

[0022] Additionally, the premixing device within the gas dilution module consists of a static mixer that uniformly mixes the dilution gas with a portion of the feed stream.

[0023] A second aspect of the present application discloses a method of using the system of the first aspect to supply acetylene, the method comprising: (1) providing at least one acetylene storage unit supplying a feed stream comprising acetylene and a solvent; (2) providing a gas dilution module that mixes a portion of the feed stream with a dilution gas according to a certain ratio to obtain a gas mixture to be measured; (3) providing a detection module, in which the mixed gas to be measured enters a photoionization detector and is ionized by excitation to generate a measurement signal, and a control unit receives the measurement signal, calculates the solvent concentration in the raw stream, and outputs a corresponding control signal; (4) providing a gas supply regulation module that receives the control signal and controls the switch of the acetylene storage device; A method is disclosed that includes:

[0024] Further, in step (3), the linear characteristic equation is written into the control unit, and the solvent concentration in the feed stream is calculated based on the measurement signal and the linear characteristic equation.

[0025] Additionally, in step (3), the control unit further compares the calculated solvent concentration in the feed stream with a solvent concentration preset value.

[0026] Further, in step (3), the calculated solvent concentration and the flow rate value of the feed stream are integrated by the control unit to determine the total amount of solvent delivered downstream for comparison with a preset value for the total amount of solvent.

[0027] Compared with the prior art, the technical solution provided in the present invention has the following advantages: 1. The applicant has unexpectedly discovered that a photoionization detector can be used to detect the solvent content of acetylene cylinders. The photoionization detector has the advantages of high accuracy, fast response, and continuous testing. 2. By mixing a part of the feed stream with dilution gas in a certain ratio, the interference of acetylene background on solvent content detection can be effectively eliminated, thereby realizing real-time continuous detection. 3. The method of the present application serves as a means to test filled acetylene cylinders to determine whether the initial solvent content is too high. 4. By integrating the solvent concentration and flow rate values ​​of the main pipeline feed stream in the control unit, the total amount of solvent delivered downstream in the batch production can be calculated. An alarm strategy is deployed to trigger an alarm when the total amount of solvent reaches a preset value.

[0028] The advantages and spirit of the present application can be further understood from the following detailed description of the invention and the accompanying drawings. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 shows a schematic flow chart of a system for supplying acetylene in an embodiment of the present invention. [Figure 2] Figure 2 shows the change in calculated acetone concentration in the feed stream for different dilution factors. [Figure 3] Figure 3 shows the solvent concentration (ppm) corresponding to the residual pressure in the acetylene cylinder measured by gas chromatography-flame ionization detector (GC-FID). [Figure 4] FIG. 4 shows the voltage value (mV) corresponding to the residual pressure in the acetylene cylinder, output by the PID. [Figure 5] FIG. 5 shows the fitting curve of the voltage values ​​output by the PID and the solvent concentration values ​​measured by the GC-FID. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, specific embodiments of the present application will be described in detail with reference to the accompanying drawings. However, it should be understood that the present application is not limited to the embodiments described below, and the technical idea of ​​the present application may be implemented in combination with other known technologies or other technologies having the same functions as those known technologies.

[0031] In the following description of specific embodiments, a number of directional terms are used in the description to clearly illustrate the structure and method of operation of the present application, but terms such as "front," "rear," "left," "right," "outer," "inner," "outward," "inward," "axial," "radial," etc. should be understood to be terms of convenience rather than limitations.

[0032] In the following description of specific embodiments, it should be understood that the directions or positional relationships indicated by terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," and "outside" are based on the directions or positional relationships shown in the drawings and are intended merely to facilitate and simplify the description of the present application, and do not suggest or imply that the referred to devices or elements must have a particular orientation or be configured and operated in a particular orientation, and therefore should not be understood as limiting the present application.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only, without limiting the chronological order, quantity, or importance. They should not be interpreted as indicating or implying relative importance or implicitly specifying the number of technical features described, but are merely intended to distinguish one technical feature from another in the technical solution. Therefore, features defined as "first" and "second" explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" means two or more unless explicitly and specifically specified otherwise. Similarly, modifiers similar to "a" appearing in this specification do not indicate a limitation of quantity, but rather describe technical features not appearing in the preceding sentence. Similarly, unless modified by a specific measure of quantity, nouns in this specification should be considered to include both the singular and the plural. That is, a technical solution may include only one of the technical features, but may also include multiple technical features. Similarly, modifiers such as "approximately" and "about" that appear before a number herein generally include that number, and the specific meaning should be understood with reference to the context.

[0034] It should be understood that in this application, "at least one" means one or more, and "plurality" means two or more. The term "and / or" is used to describe a relationship between related objects and indicates that three relationships may exist. For example, "A and / or B" refers to three situations: only A is present, only B is present, or both A and B are present (where A and B may be singular or plural). The symbol " / " generally indicates an "or" relationship between related objects. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single item(s) or multiple items. For example, at least one of a, b, or c can mean a, b, c, "a and b," "a and c," "b and c," or "a and b and c," where a, b, and c may be singular or plural.

[0035] In this application, unless expressly specified and defined otherwise, terms such as "installed," "connected," "connecting," and "fixed" should be understood broadly. For example, there may be a fixed connection, or a detachable connection, or the connection may be integral, or there may be a mechanical connection, or there may be an electrical connection, or there may be a direct connection, or there may be an indirect connection via an intermediate medium, or there may be internal communication between two elements, or an interactive relationship between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific situation. The expressions "fixedly connected," "fixed connection," or "immovably connected" are understood to mean that the connection between two or more structural members is not configured to allow relative movement between them. Examples of fixed connections include welded joints or bolted connections, and in some cases, weld seams and bolted connections. The expressions "movably connected," "movable," or "movable connection" are understood to mean that the connection between two or more structural members allows horizontal and / or vertical relative movement between the members under extreme driving force loads. Such connections generally do not allow movement under dead loads or normal driving loads (eg, as exerted by light / moderate wind forces).

[0036] The terms "unit," "component," "object," and "module" used in this specification refer to a unit used to process at least one function or operation, and can be implemented by hardware components or software components or a combination thereof.

[0037] As used herein, the phrase "substantially solvent-free" means containing 300 ppm or less of solvent, preferably 200 ppm or less of solvent, more preferably 100 ppm or less of solvent, and most preferably 80 ppm or less of solvent.

[0038] Unless expressly indicated otherwise, each aspect or embodiment defined herein can be combined with any other aspect or embodiment, and in particular any preferred or advantageous feature indicated can be combined with any other preferred or advantageous feature indicated.

[0039] Photoionization detectors (PIDs) can be used to detect the concentration of volatile organic compounds. A PID uses an ultraviolet lamp with a specific ionization energy (e.g., 10.6 eV) to generate ultraviolet light, which ionizes organic compounds into positively charged ions and negatively charged electrons. Under the influence of an external electric field, the ions and electrons move in a certain direction, forming a detectable photoionization current. Because there is a linear relationship between the concentration of the organic compound being measured and the photoionization current, the concentration of the detected organic compound can be determined based on the value of the photoionization current. While the PID's response signal is related to changes in ionization, it can be affected by other interfering signals, resulting in signal artifacts. For example, the presence of interfering molecules that absorb ultraviolet light and generate a response signal reduces the detector's sensitivity.

[0040] The mass flow controllers referred to herein may use operating principles well known to those skilled in the art to achieve stable and accurate mass flow measurements.

[0041] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following embodiments, two acetylene cylinders or a set of two or more acetylene cylinders are used as the acetylene storage device.

[0042] The acetylene supply system provided in this embodiment provides stable, compliant, and continuous delivery of acetylene to equipment that uses acetylene in downstream processes by detecting the solvent concentration in the feed stream from an acetylene storage device in real time. The system includes two acetylene cylinders or a set of two or more acetylene cylinders as the acetylene storage device. Based on the real-time monitoring results of the solvent concentration in the feed stream output from each acetylene cylinder, automatic replacement of the acetylene cylinder / acetylene cylinder set can be performed more accurately. If the solvent concentration in the feed stream exceeds a preset value or the acetylene concentration is detected as being too low, the system can automatically replace the acetylene cylinder with a new one.

[0043] As shown in Figure 1, the numbers 1 and 2 indicate acetylene cylinders, which are used as acetylene storage devices to supply acetylene to downstream devices that use acetylene.

[0044] The numeral 3 in Figure 1 indicates a diluent gas storage device for storing diluent gas. In this embodiment, the diluent gas includes, but is not limited to, an inert gas such as nitrogen or argon. These inert gases may be cylinder gases well known to those skilled in the art.

[0045] The numeral 4 in Figure 1 denotes a gas dilution module, the function of which is to mix a portion of the feed stream uniformly with a dilution gas according to a certain ratio.

[0046] The numeral 5 in FIG. 1 represents the detection module. The control unit and the PID therein are electrically connected. The raw material stream flowing out from the acetylene storage device converges into the main pipeline, and the raw material stream is delivered to the acetylene-using device through the main pipeline. A portion of the raw material stream is led out from the main pipeline and enters the PID of the detection module 5. The detection principle of the PID will not be repeated in this application. The PID forms a detectable photoionization current signal and outputs a measurement signal.

[0047] The control unit includes a central processing unit, an internal memory, an input device, and an output device. The input device receives the measurement signal output by the photoionization detector. A linear characteristic equation of acetone concentration versus response voltage is stored in the central processing unit, and a solvent concentration value is calculated based on the measurement signal. At the same time, the control unit can compare the solvent concentration value with a preset solvent concentration value and output a corresponding control signal via the output device. If necessary, the control unit can also display a graph of real-time fluctuations in the solvent concentration of the feed stream being delivered.

[0048] As known to those skilled in the art, the above central processing unit, internal memory, input devices, and output devices may be integrated into a single-chip microcomputer or programmable controller (PLC). The solvent content data is recorded in the internal memory of the control unit.

[0049] As shown in Figure 1, PR1 represents a first pressure regulator that adjusts the pressure of a portion of the feed stream entering the gas dilution module, and PR2 represents a second pressure regulator that adjusts the pressure of the dilution gas entering the gas dilution module.

[0050] SW in Figure 1 represents a solenoid valve. When the solvent concentration of one acetylene cylinder / set of one acetylene cylinder exceeds a preset value, the solenoid valve switches to the other acetylene cylinder / set of other acetylene cylinders under the control of the control unit.

[0051] BV1 and BV2 in Figure 1 are ball valves that can be used to direct a portion of the feed stream to the detection module and can also be used to isolate upstream gas during maintenance of the entire system.

[0052] PT1 and PT2 in Fig. 1 are pressure transmitters. They are connected to the acetylene cylinders and are also electrically connected to the control unit 5. These pressure transmitters can convert the pressure value of the raw material stream coming out of the acetylene cylinder into a pneumatic signal or an electrical signal and send it to the control unit.

[0053] BV1 is opened and a portion of the low flow feed stream is led from the main pipeline to the gas dilution module 4. The pressure of this portion of the feed stream is regulated to below 0.5 barg by PR1. BV2 is opened and the dilution gas has its pressure regulated to above 2 barg by PR2 and enters the gas dilution module 4.

[0054] As an example, after the output of the feed stream by acetylene cylinder 1 or 2, and after pressure regulation by PT1 or PT2, the pressure of the feed stream delivered by the main pipeline is 1.5 barg or less.

[0055] For example, if a 40L acetylene cylinder is just opened, the amount of solvent volatilized is still very small, so there is no need to immediately activate the PID to detect the amount of solvent. The PID will be activated to detect when the pressure of the raw stream output by the acetylene cylinder drops to approximately 10-12 kg, allowing for a fairly accurate determination of when to switch acetylene cylinders. If the acetylene gas pressure output by acetylene cylinder 1 or 2 is too low, for example, below approximately 4 barg, based on experience, it can be determined that the acetylene concentration in the raw stream output by the acetylene cylinder does not meet the requirements of the downstream process. Switching the switch, thereby switching to a new acetylene cylinder, is necessary.

[0056] In addition to the field of low-pressure carburization, the system and method of the present application can be used in various situations where the filling status of acetylene cylinders needs to be monitored. For example, during the filling process of acetylene cylinders, there is a certain probability that the porous calcium silicate adsorbent will break down and deteriorate over time. Currently, most acetylene cylinder users only notice this after using the acetylene cylinder. The system and method of the present application allows for the use of a PID as a check immediately after filling to determine whether the solvent content is too high.

[0057] In actual applications, acetylene is the predominant component in the raw material stream output from an acetylene cylinder, although this varies from about 99.9% to about 97%. It has been known that most of the acetylene is ionized when passing through a PID, which interferes with solvent detection and affects sensitivity. Therefore, the inventors first investigated a method to reduce the effect of acetylene on solvent detection.

[0058] The inventors have found that this problem can be effectively solved by configuring a gas dilution module where the feed stream and dilution gas are mixed in a fixed ratio to reduce the degree to which acetylene interferes with solvent detection, so that when acetylene subsequently enters the PID, solvent detection sensitivity is increased.

[0059] To investigate the effect of acetylene in the feed stream on the measurement of solvent content (e.g., acetone), we investigated the ratio of diluent gas to feed stream.

[0060] We stabilize the feed stream flow rate at a low concentration level, as opposed to the range of several hundred liters per hour that occurs under normal operating conditions. At such low flow rates, there is no significant increase in the acetone content in the feed stream, and the actual acetone content fluctuates only slightly.

[0061] Therefore, in order to determine an appropriate range for the dilution gas ratio, the following experiment was planned.

[0062] First step: Pass standard gases containing low and high concentrations of acetone through the PID. Assume that the response voltage (mV) obtained after the two standard gases enter the PID is linear, and then obtain a linear characteristic equation for the acetone concentration-response voltage. Second step: Prepare an acetylene cylinder and stabilize the flow rate of the feed stream at approximately 5-20 ml / min. At this low flow rate, the acetone concentration in the feed stream fluctuates very little, and the inventors believe that the acetone concentration can be considered constant. Third step: The flow rates of the dilution gas (e.g., nitrogen) and the feed stream are adjusted by mass flow controllers to obtain multiple sets of mixed gases to be measured with different dilution ratios. Each set of mixed gases to be measured is input into the PID separately to obtain the corresponding response voltage (mV). Fourth step: Based on the linear characteristic equation obtained in the first step and the response voltage value in the third step, calculate the concentration of acetone entering the PID, and then multiply each set by the corresponding dilution factor to calculate the acetone concentration in the feed stream.

[0063] Figure 2 shows that at the initial low dilution ratio, the acetone concentration value continuously increases due to the influence of the acetylene background. As the dilution ratio increases, the influence of the acetylene background continues to decrease, and the acetone concentration value tends to remain constant, indicating that the dilution ratio is appropriate. When the volume ratio of dilution gas to feed stream is less than 50 or even less than 60, the detected acetone content becomes unstable. This is because the degree of acetone signal attenuation is still very high when the dilution gas is small. When the volume ratio of dilution gas to feed stream is greater than 50 or even greater than 60, the detected acetone content essentially stabilizes. This indicates that the signal attenuation caused by acetylene has essentially disappeared. As the dilution gas ratio is further increased, the measured acetone content stabilizes and no longer fluctuates due to the reduced attenuation effect.

[0064] Therefore, taking into consideration the effectiveness and uniformity of the measurement, in the following embodiments, the volume ratio of the dilution gas to the raw material stream (i.e., the dilution factor) is set to 60, which can effectively reduce the influence of ultraviolet energy absorption by acetylene.

[0065] To verify the effectiveness of the system and method of the present application, the inventors used a gas chromatography-flame ionization detector (GC-FID) to detect solvent concentration values. A test acetylene cylinder was prepared, and a portion of the raw stream was discharged from the main pipeline. At various residual pressures in the acetylene cylinder, the GC-FID was used to detect solvent concentration values ​​at the corresponding residual pressures. The results are shown in Figure 3. As the raw stream in the acetylene cylinder was released, the residual pressure decreased, and the solvent concentration increased essentially linearly. Similarly, another portion of the raw stream was discharged from the main pipeline and entered the PID. The results are shown in Figure 4. As the raw stream in the acetylene cylinder was discharged, the residual pressure decreased, and the voltage value indicated by the PID gradually increased, showing the same trend as in Figure 3.

[0066] The data in Figures 3 and 4 were fitted as shown in Figure 5. The response voltage values ​​of the PID and the solvent concentration values ​​of the GC-FID showed a relatively clear positive correlation.

[0067] It can be seen that the voltage value output by the photoionization sensor and the acetone concentration value have a very good linear response relationship. This linear response relationship is written into the control unit to establish a linear characteristic equation for the acetylene cylinder.

[0068] In this way, during delivery of the feed stream, the control unit can receive the measurement signal emitted by the PID and input it into the linear characteristic equation for calculation to obtain the solvent concentration value of interest.

[0069] For example, if acetylene cylinder 1 is selected for operation, as time passes, when the solvent concentration calculated via the control unit exceeds a preset value, the solenoid valve SW is switched to change to acetylene cylinder 2 to supply the raw material stream.

[0070] The UV light source in the PID provides UV light at a specific energy level. When the acetylene and solvent mixture passes through the PID's porous membrane and enters the measurement gas chamber, the solvent absorbs the UV light energy and is ionized, generating an electrical signal between the PID's electrodes. FT represents a flow sensor electrically connected to the control unit. The total amount of solvent delivered downstream can be determined by integrating the calculated solvent concentration and the flow sensor's flow rate value in the control unit. An alarm is triggered when the value reaches a preset threshold for the total solvent amount.

[0071] What has been described in the above specification is merely a preferred specific embodiment of the present application, and the aforementioned embodiment is merely used to describe the technical solution of the present application without limiting the present application. All technical solutions that a person skilled in the art can obtain through logical analysis, reasoning, or limited experiments based on the concept of the present application should fall within the scope of the present application. [Explanation of symbols]

[0072] 1 acetylene cylinder 2 acetylene cylinders 3 Dilution gas storage device 4 Gas Dilution Module 5. Detection Module SW solenoid valve PR1 First Pressure Regulator PR2 Secondary Pressure Regulator BV1 ball valve BV2 ball valve PT1 Pressure Transmitter PT2 Pressure Transmitter FT Flow Sensor

Claims

1. 1. A system for supplying acetylene comprising: at least one acetylene storage unit providing a feed stream comprising acetylene and a solvent; a gas dilution module for uniformly mixing a portion of the feed stream with a dilution gas in a certain ratio to obtain a gas mixture to be measured, the gas dilution module including a pressure equalization device, a filtration device, a flow rate regulator, and a premixing device; a detection module including a photoionization detector and a control unit, wherein the mixed gas to be measured enters the photoionization detector and is ionized by excitation to generate a measurement signal, and the control unit is configured to calculate a solvent concentration based on the measurement signal from the photoionization detector, compare it with a solvent concentration preset value, and output a control signal; a gas supply regulation module comprising a solenoid valve, a pressure transmitter and a flow sensor, all electrically connected to the control unit, the solenoid valve being used to exchange each acetylene storage device, the pressure transmitter being used to detect the pressure of the feed stream output by each acetylene storage device, and the flow sensor being used to detect the flow rate of the feed stream supplied to an acetylene-using device; Equipped with the solvent is acetone, the diluent gas is nitrogen; 10. The system of claim 9, wherein in said gas dilution module, a volume ratio of said dilution gas to said portion of said feed stream is 50 or greater.

2. 2. The system of claim 1, wherein in said gas dilution module, the volume ratio of said dilution gas to said portion of said feed stream is 60 or greater.

3. 2. The system of claim 1, wherein the acetylene storage device is an acetylene cylinder or a set of acetylene cylinders.

4. 10. The system of claim 1, wherein the pressure equalization device in the gas dilution module comprises a first pressure regulator that adjusts the pressure of the portion of the feed stream and a second pressure regulator that adjusts the pressure of the dilution gas.

5. 5. The system of claim 4, wherein the first pressure regulator regulates the pressure of the portion of the feed stream entering the gas dilution module to 0.5 barg or less.

6. 2. The system according to claim 1, wherein a linear characteristic equation of acetone concentration versus response voltage is stored in the control unit.

7. 10. The system of claim 1, wherein the flow regulators in the gas dilution module comprise a first flow regulator that regulates the flow of the portion of the feed stream and a second flow regulator that regulates the flow of the dilution gas.

8. 8. A method of using a system according to any one of claims 1 to 7 to supply acetylene, comprising the steps of: (1) providing at least one acetylene storage unit supplying a feed stream comprising acetylene and a solvent; (2) providing a gas dilution module that mixes a portion of the feed stream with a dilution gas according to a ratio to obtain a gas mixture to be measured; (3) providing a detection module, in which the mixed gas to be measured enters a photoionization detector and is ionized by excitation to generate a measurement signal, and a control unit receives the measurement signal, calculates the solvent concentration in the feed stream, and outputs a corresponding control signal; (4) providing a gas supply regulation module that receives the control signal and controls a switch of the acetylene storage device; A method comprising:

9. 9. The method of claim 8, wherein in step (3), a linear characteristic equation is written into the control unit, and the solvent concentration in the feed stream is calculated based on the measurement signal and the linear characteristic equation.

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