Fluid mixture detection system and detection method

Abstract

The present invention discloses a detection system and a detection method for a fluid mixture. The detection system includes a pipeline assembly, a first valve, a gas chromatograph and a vacuum pump, wherein the pipeline assembly includes a first pipeline and a second pipeline; the first valve is connected to the first pipeline, and the first valve is used to control the circulation of the fluid mixture obtained by the reactor reaction; the gas chromatograph has an injection end and an output end, the injection end is connected to an end of the first pipeline away from the first valve, and the output end is connected to the second pipeline; the vacuum pump is connected to an end of the second pipeline away from the gas chromatograph. The detection system and the detection method of the present invention reduce the delay error, avoid the dissolution error, and can also avoid the volatilization and escape of products with a boiling point close to room temperature or with high volatility. After the fluid mixture obtained by the reaction is completely gasified, it is directly injected into the gas chromatograph to realize online gas chromatography detection and reduce the measurement error.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluid detection, and in particular relates to a detection system and a detection method for a fluid mixture. Background Art

[0002] For the fluid mixture generated by the chemical reaction in the reactor, gas chromatography or liquid chromatography is generally used for separation and detection, but the offline component detection method based on cooling and depressurization-gas-liquid separation sampling generally has measurement errors. For example, it takes a certain time for the cracking products in the high temperature or high temperature and high pressure reactor to cool down from the beginning. In this process, the cracking reaction continues to proceed under the state of deviating from the preset working conditions. When the ratio of the delay cooling time to the program heating time in the cracking reactor is large, it may cause a certain deviation in the raw material conversion rate and the obtained product component distribution during offline sampling. Or some normal temperature and pressure gas products may have strong solubility in liquid products. The dissolution of gas products in liquid products makes the gas production rate data obtained by measuring the mass flow rate of gas products relatively low, and will also cause a certain deviation in the gas component yield data obtained by measuring the gas product samples. In addition, under room pressure, the components that are partially cooled and in liquid form have a boiling point close to room temperature or are highly volatile. After the gas-liquid separation is completed, the above products and the gas products dissolved in the liquid products may partially escape from the liquid samples during sample collection and detection, thereby causing measurement errors. Summary of the invention

[0003] The present invention provides a fluid mixture detection system and a detection method to solve the technical problem of measurement error in the existing fluid mixture detection system and method.

[0004] A first aspect of the present invention provides a fluid mixture detection system, comprising a pipeline assembly, a first valve, a gas chromatograph and a vacuum pump, wherein the pipeline assembly comprises a first pipeline and a second pipeline; the first valve is connected to the first pipeline, and the first valve is used to control the flow of the fluid mixture obtained by the reactor reaction; the gas chromatograph has an injection end and an output end, the injection end is connected to an end of the first pipeline away from the first valve, and the output end is connected to the second pipeline; the vacuum pump is connected to an end of the second pipeline away from the gas chromatograph.

[0005] In some embodiments, the detection system further includes an injection needle and a cooler, one end of the injection needle is used to be inserted into the reactor, and the other end is connected to the first valve, and the cooler is sleeved on the outer circumference of the injection needle.

[0006] In some embodiments, the detection system further includes a pulse power supply connected to the first valve, and the pulse power supply is used to drive the first valve to open and close.

[0007] In some embodiments, the detection system also includes a second valve arranged on the second pipeline, the second valve is located between the vacuum pump and the gas chromatograph, the second valve is a one-way valve, and the flow direction is along the second pipeline and from the gas chromatograph to the vacuum pump.

[0008] In some embodiments, the threshold pressure of the second valve is less than the saturated vapor pressure of the component with the highest boiling point in the fluid mixture.

[0009] In some embodiments, the detection system further includes a third pipeline and a third valve disposed on the third pipeline, and both ends of the third pipeline are connected to the first pipeline and the second pipeline respectively.

[0010] In some embodiments, the detection system also includes a first pressure sensor arranged on the first pipeline and a second pressure sensor arranged on the second pipeline, the first pressure sensor is located between the first valve and the gas chromatograph, and the second pressure sensor is located between the vacuum pump and the gas chromatograph.

[0011] In some embodiments, the detection system further comprises a heating element, and surfaces of the first valve, the pipeline assembly and the gas chromatograph that are in contact with the fluid mixture are respectively provided with heating elements.

[0012] In some embodiments, the gas chromatograph includes at least two channels for synchronously analyzing different components, and both ends of each channel are connected to the first pipeline and the second pipeline respectively.

[0013] In addition, the second aspect of the present invention provides a method for detecting a fluid mixture, using a detection system of any of the above-mentioned embodiments, and the detection method includes the following steps: closing the first valve; using a vacuum pump to evacuate the first pipeline, the gas chromatograph and the second pipeline; opening the first valve to allow the fluid mixture to enter the first pipeline and flash evaporate into a gas mixture; and using a gas chromatograph to perform online detection of the gas mixture.

[0014] In some embodiments, the step of opening the first valve includes: using a pulse power supply to drive the first valve to open and close continuously; wherein the pulse width of the pulse signal of the pulse power supply is less than 10 ms, and the frequency of continuous opening and closing of the first valve is 1 to 10 Hz.

[0015] The present invention closes the first valve, uses a vacuum pump to evacuate the pipeline assembly and the gas chromatograph, and then opens the first valve. Since the valve core of the first valve is in a low-pressure state on one side of the gas chromatograph, the pressure difference before and after the first valve allows the fluid mixture to quickly enter the first pipeline. If the gas mixture is a product in a high-temperature or high-temperature and high-pressure reactor, the cooling time can be reduced and the delay error can be reduced. In addition, for a gas-liquid mixture, when the fluid mixture enters the low-pressure first pipeline, the pressure suddenly decreases, which can enable the fluid mixture to flash, and the liquid in the fluid mixture is all volatilized into gas, becoming a gas mixture, preventing some gas phase components from dissolving in the liquid phase components, and avoiding dissolution errors. Moreover, the boiling point of the fluid mixture is reduced under a low-pressure environment, so it can also be avoided that the boiling point is close to room temperature or the product with strong volatility escapes. The present invention directly injects the fluid mixture obtained by the reaction into the gas chromatograph after it is completely gasified, realizing online gas chromatography detection, and reducing measurement errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a fluid mixture detection system provided in some embodiments of the present invention;

[0017] Figure 2 Schematic diagram of a fluid mixture detection system provided by other embodiments of the present invention;

[0018] Figure 3 Schematic diagram of a fluid mixture detection system provided for still further embodiments of the present invention.

[0019] The reference numerals are as follows: pipeline assembly 10; first pipeline 11; second pipeline 12; third pipeline 13; first valve 21; gas chromatograph 30; injection end 31; sample outlet end 32; vacuum pump 40; injection needle 50; cooler 60; second valve 22; third valve 23; first pressure sensor 71; second pressure sensor 72; reactor 80. DETAILED DESCRIPTION

[0020] In order to make the invention purpose, technical scheme and beneficial technical effect of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the embodiments described in this specification are only for explaining the present invention, not for limiting the present invention.

[0021] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unambiguous range; and any lower limit can be combined with other lower limits to form an unambiguous range, and any upper limit can be combined with any other upper limit to form an unambiguous range. In addition, although not explicitly stated, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unambiguous range.

[0022] In the description of this document, it should be noted that, unless otherwise specified, “several” means one or more than one; “several (kinds)” means two (kinds) or more; “above” and “below” include the number itself; the terms “upper”, “lower”, “inside” and “outside” etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of description and simplification of description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on this document.

[0023] The above summary of the invention of the present invention is not intended to describe each disclosed embodiment or each implementation in the present invention. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided by a series of examples, which can be used in various combinations. In each example, enumeration is only used as a representative group and should not be interpreted as exhaustive.

[0024] Thermal cracking of organic matter under high temperature and high pressure conditions has been widely used in the fields of waste-to-energy and aerospace thermal protection. The component detection of cracking products with significant boiling point differences under high temperature and high pressure is a prerequisite for the development of related technologies. However, the common offline component detection method based on cooling and depressurization-gas-liquid separation sampling will introduce three types of errors: dissolution, volatilization, and delay, which will affect the research accuracy of the thermal cracking reaction mechanism model.

[0025] The first type is delay error: it takes a certain amount of time for the cracking products in the high-temperature (and high-temperature and high-pressure) reactor to cool down from the beginning to the end of the reaction. During this process, the cracking reaction continues to proceed under the conditions that deviate from the preset operating conditions. When the delay cooling time is large compared to the program heating time in the cracking reactor, it may cause a certain deviation in the raw material conversion rate and the obtained product component distribution during offline sampling. The size of the delay error is directly related to the cooling time. The experimental systems and working conditions of different institutions are designed differently, and the delay errors introduced in the experiment are also different.

[0026] The second type is dissolution error: some gas products produced by thermal cracking of organic matter at room temperature and pressure can have strong solubility in liquid products. For example, hydrocarbons are common and important target products of thermal cracking of organic matter, and are widely present in mixtures of gas and liquid products. Since hydrocarbon molecules often have strong similarities, C4-low carbon hydrocarbons in gaseous state at room temperature and pressure have strong solubility in C5+ hydrocarbons in liquid phase. The dissolution of gas products in liquid products makes the gas production rate data obtained by measuring the mass flow rate of gas products relatively low, and will also cause certain deviations in the gas component yield data obtained by measuring gas product samples.

[0027] The third type is volatility error: at room pressure, some components that are in liquid phase after cooling have a boiling point close to room temperature or strong volatility, such as methanol, ethanol, C5 hydrocarbons, etc. After the gas-liquid separation is completed, the above products and gas products dissolved in the liquid products can partially escape from the liquid sample during the sample collection and detection process, thus causing measurement errors.

[0028] The embodiment of the first aspect of the present invention provides a detection system for a fluid mixture, such as Figure 1 As shown, it includes a pipeline assembly 10, a first valve 21, a gas chromatograph 30 and a vacuum pump 40, the pipeline assembly 10 includes a first pipeline 11 and a second pipeline 12; the first valve 21 is connected to the first pipeline 11, and the first valve 21 is used to control the flow of the fluid mixture obtained by the reaction of the reactor 80; the gas chromatograph 30 has an injection end 31 and an output end 32, the injection end 31 is connected to an end of the first pipeline 11 away from the first valve 21, and the output end 32 is connected to the second pipeline 12; the vacuum pump 40 is connected to an end of the second pipeline 12 away from the gas chromatograph 30.

[0029] It should be noted that the detection system of the fluid mixture of the embodiment of the present invention is particularly suitable as a detection system for high-temperature and high-pressure fluid pyrolysis products (having gas phase components and liquid phase components) with significant boiling point differences, but is not limited to being a detection system for high-temperature and high-pressure fluid pyrolysis products with significant boiling point differences. If other fluid mixtures are applied with the detection system provided by the present invention, they should also fall within the protection scope of the present invention. For example, the detection system of the embodiment of the present application can also be applied to pure gas phase mixtures, pure liquid phase mixtures, or non-high temperature fluid mixtures. For ease of understanding, the following description is based on the high-temperature and high-pressure thermal cracking reaction occurring in the reactor 80.

[0030] In the embodiment of the present invention, the first valve 21 is closed, and the pipeline assembly 10 and the gas chromatograph 30 are evacuated by using a vacuum pump 40, and then the first valve 21 is opened. Since the valve core of the first valve 21 is in a low-pressure state on the side facing the gas chromatograph 30, the pressure difference before and after the first valve 21 allows the fluid mixture to quickly enter the first pipeline 11. If the gas mixture is a product in a high-temperature or high-temperature and high-pressure reactor 80, the cooling time can be reduced and the delay error can be reduced. In addition, for a gas-liquid mixture, when the fluid mixture enters the low-pressure first pipeline 11, the pressure suddenly decreases, which can enable the fluid mixture to flash, and the liquid in the fluid mixture is all volatilized into gas, becoming a gas mixture, preventing certain gas phase components from dissolving in the liquid phase components, and avoiding dissolution errors. Moreover, the boiling point of the fluid mixture is reduced under a low-pressure environment, so it can also prevent the product with a boiling point close to room temperature or a strong volatility from evaporating. The present invention directly injects the fluid mixture obtained by the reaction into the gas chromatograph 30 after it is completely gasified, realizing online gas chromatography detection and reducing measurement errors.

[0031] It should be noted that flash evaporation refers to the phenomenon that when a high-pressure saturated liquid enters a relatively low-pressure container, due to the sudden drop in pressure, the saturated liquid becomes saturated steam and saturated liquid under a portion of the container pressure.

[0032] In some embodiments, the detection system further includes an injection needle 50 and a cooler 60 . One end of the injection needle 50 is used to be inserted into the reactor 80 , and the other end is connected to the first valve 21 . The cooler 60 is sleeved on the outer periphery of the injection needle 50 .

[0033] This embodiment uses a micro injection needle 50, the diameter and length of which are small enough to avoid interfering with the cracking reaction of the raw material in the reactor 80, and to avoid the excessive volume in the injection needle 50 causing the sample to be collected to stay in the injection needle 50 for a long time. At the same time, the cooler 60 uses a micro cooler 60, so that a small amount of high-temperature and high-pressure fuel-cracking product mixture is instantaneously along the injection needle 50 under the huge pressure difference on the left and right sides of the valve core of the first valve 21, cooled by the micro cooler 60, and enters the first pipeline 11 through the first valve 21 after instantaneous cooling. Specifically, the temperature of the micro cooler 60 can be adjusted so that the temperature of the fluid mixture entering the first valve 21 after cooling does not exceed 473K, so that the reaction is instantly frozen. The sampling method of instantaneous cooling and flash evaporation under low pressure avoids the detection error caused by the delayed reaction termination lag caused by delayed cooling of the sample after leaving the reactor 80.

[0034] In some embodiments, the detection system further includes a pulse power supply connected to the first valve 21, and the pulse power supply is used to drive the first valve 21 to open and close. The first valve 21 is a fast solenoid valve, and the pulse power supply drives the first valve 21 to open and close continuously at a frequency of about 1 to 10 Hz with a pulse signal with a pulse width of less than 10 ms. Each time the valve core of the first valve 21 is opened, a small amount of fluid mixture in the reactor 80 is instantly introduced into the first pipeline 11 along the injection needle 50 through the cooler 60 and the first valve 21 under the huge pressure difference on the left and right sides of the valve core. In addition, by continuously opening and closing the first valve 21 for injection, the components of the fluid mixture can be evenly distributed in various places in the pipeline assembly 10.

[0035] Optionally, the first valve 21 has a maximum withstand pressure of 553K, a high-pressure end withstand pressure of 10MPa, and a low-pressure outlet end can work under vacuum conditions. When a high-frequency pulse power supply is used to drive the first valve 21, when the driving voltage is 24V and the pulse width PW is less than 10ms, the valve core of the first valve 21 can be opened and closed within 10ms. It is understandable that the voltage and pulse width of the pulse power supply can be adjusted to adjust the opening and time of the first valve 21.

[0036] In some embodiments, the detection system further includes a second valve 22 disposed on the second pipeline 12, the second valve 22 is located between the vacuum pump 40 and the gas chromatograph 30, and the second valve 22 is a one-way valve, and the flow direction is along the second pipeline 12 and from the gas chromatograph 30 to the vacuum pump 40. In other words, the fluid mixture can flow from the gas chromatograph 30 to the vacuum pump 40 through the one-way valve, but cannot flow from the vacuum pump 40 to the gas chromatograph 30 through the one-way valve, thereby preventing the fluid mixture drawn away by the vacuum pump 40 from flowing back to the gas chromatograph 30, and further reducing the measurement error.

[0037] In some embodiments, the threshold pressure of the second valve 22 is less than the saturated vapor pressure of the component corresponding to the highest boiling point value in the fluid mixture. Since the second valve 22 is a one-way valve, the second valve 22 has a threshold pressure, and only when the pressure on the side of the second valve 22 facing the gas chromatograph 30 is greater than or equal to the threshold pressure of the second valve 22, the second valve 22 will open to allow the fluid to pass through. If the pressure on the side of the second valve 22 facing the gas chromatograph 30 is less than the threshold pressure of the second valve 22, the second valve 22 will not open. It can be understood that the threshold pressure of the second valve 22 can be adjusted and set. In this embodiment, the threshold pressure of the second valve 22 is set to be less than the saturated vapor pressure of the component corresponding to the highest boiling point value in the fluid mixture. Since the pyrolysis product mixture under high temperature and high pressure to be collected has a significant difference in boiling points, it is assumed that in the pyrolysis product mixture, component A is the most difficult to volatilize, that is, its saturated vapor pressure P in the pipeline assembly 10 is less than 1. 饱和 If the saturated vapor pressure of the one-way valve is lower than that of all other components, the one-way valve opening threshold pressure P should be adjusted.阈值 , making it lower than P 饱和 This ensures that all the fluid mixture entering the first pipeline 11 is flash evaporated during the sampling process.

[0038] In some embodiments, the detection system further includes a heating element (not shown), and the surfaces of the first valve 21, the pipeline assembly 10 and the gas chromatograph 30 that are in contact with the fluid mixture are respectively provided with heating elements. Specifically, except for the injection needle 50 and the vacuum pump 40, the wet surfaces of all devices such as the first valve 21, the gas chromatograph, the second valve 22 and the pipeline assembly 10 (the inner surface of the device through which the fluid mixture can flow and contact) can be heated to a set preheating temperature and kept constant to prevent the fluid mixture from condensing into a liquid and causing measurement errors. Among them, the heating element can be a thermocouple, a heating wire, etc.

[0039] As a preferred embodiment, the heating element is a thermocouple, and a multi-loop PID temperature control system is used in conjunction with a thermocouple welded on the inner surface of the equipment to preheat the inner surface of the equipment and measure and control the temperature.

[0040] In some embodiments, Figure 2 As shown, the detection system further includes a third pipeline 13 and a third valve 23 disposed on the third pipeline 13, and the two ends of the third pipeline 13 are respectively connected to the first pipeline 11 and the second pipeline 12. Since the distance between the vacuum pump 40 and the first valve 21 is relatively far, when vacuuming, the fluid mixture needs to pass through the gas chromatograph 30 and other equipment, and the gas chromatograph 30 has many pipeline channels and a small diameter, which may result in poor vacuuming effect. In this embodiment, by disposing the third pipeline 13, when vacuuming, the third valve 23 is opened, so that the vacuum degree of the pipeline assembly 10, especially the first pipeline 11, is reduced, and the vacuuming effect is improved.

[0041] In some embodiments, Figure 3 As shown, the detection system also includes a first pressure sensor 71 arranged on the first pipeline 11 and a second pressure sensor 72 arranged on the second pipeline 12. The first pressure sensor 71 is located between the first valve 21 and the gas chromatograph 30, and the second pressure sensor 72 is located between the vacuum pump 40 and the gas chromatograph 30.

[0042] The vacuum pump 40 is used to evacuate the entire pipeline after the outlet of the first valve 21, and the pressure (vacuum degree) in the pipeline is monitored using the first pressure sensor 71 and the second pressure sensor 72. The preheating system is used to heat the wet surfaces of all equipment including the first valve 21, the first pressure sensor 71, the gas chromatograph 30, the second pressure sensor 72, the second valve 22, the third valve 23 and the pipeline assembly 10 to a set preheating temperature and keep it constant. Close the third valve 23 at the left outlet of the vacuum pump 40, use a pulse power supply to drive the first valve 21 to open continuously at a frequency of 1 to 10 Hz with a pulse signal with a pulse width of less than 10 ms, keep the vacuum pump 40 open, adjust the opening threshold of the second valve 22 at the right outlet of the vacuum pump 40, and make the first valve 21 open and close continuously for sampling until the components of the fluid mixture are evenly distributed in various places in the preheated pipeline assembly 10, then close the first valve 21 and the second valve 22, monitor the rapid balance of pressure in the pipeline assembly 10 through the first pressure sensor 71 and the second pressure sensor 72 before and after the online gas chromatograph 30, and then start the online gas chromatograph 30 to detect the fluid mixture.

[0043] Preferably, a high temperature resistant low pressure sensor is used to detect the pressure in the pipeline. More preferably, the absolute pressure in the pipeline should not be higher than 100Pa.

[0044] In some embodiments, the gas chromatograph 30 includes at least two channels for synchronously analyzing different components, and both ends of each channel are respectively connected to the first pipeline 11 and the second pipeline 12. The multi-channel online gas chromatography is used to synchronously and real-time analyze the collected samples with significant boiling point differences.

[0045] In a preferred embodiment, GC-MS-FID (gas chromatography-mass spectrometry-hydrogen ion flame detector), GC-FID and GC-TCD (gas chromatography-thermal conductivity detector) three-channel online gas chromatography are used to synchronously analyze three different components of high carbon, low carbon and hydrogen in the sample. Three identical quantitative tubes are installed in series on the preheated vacuum tube. When the sampling and washing process is completed, the cracking product sample in the quantitative tube is injected into the online gas chromatograph for detection through the switching of the ten-way valve.

[0046] In addition, the second aspect of the present invention provides a method for detecting a fluid mixture, using the detection system of any of the above embodiments, the detection method comprises the following steps:

[0047] S100, closing the first valve 21;

[0048] S200, using a vacuum pump 40 to evacuate the first pipeline 11, the gas chromatograph 30 and the second pipeline 12;

[0049] S300, opening the first valve 21 to allow the fluid mixture to enter the first pipeline 11 and flash evaporate into a gas mixture;

[0050] S400, using a gas chromatograph 30 to perform online detection on the gas mixture.

[0051] By closing the first valve 21, using the vacuum pump 40 to evacuate the pipeline assembly 10 and the gas chromatograph 30, and then opening the first valve 21, since the valve core of the first valve 21 is in a low-pressure state on the side facing the gas chromatograph 30, the pressure difference before and after the first valve 21 allows the fluid mixture to quickly enter the first pipeline 11. If the gas mixture is a product in a high-temperature or high-temperature and high-pressure reactor 80, the cooling time can be reduced and the delay error can be reduced. In addition, for a gas-liquid mixture, when the fluid mixture enters the low-pressure first pipeline 11, the pressure suddenly decreases, which can enable the fluid mixture to flash, and the liquid in the fluid mixture is all volatilized into gas, becoming a gas mixture, preventing certain gas phase components from dissolving in the liquid phase components, and avoiding dissolution errors. Moreover, the boiling point of the fluid mixture is reduced under a low-pressure environment, so it can also prevent the product with a boiling point close to room temperature or a strong volatility from evaporating. The detection method of the present invention directly injects the fluid mixture obtained by the reaction into the gas chromatograph 30 after it is completely gasified, realizing online gas chromatography detection and reducing measurement errors.

[0052] In some embodiments, the step of opening the first valve 21 includes: using a pulse power supply to drive the first valve 21 to open and close continuously; wherein the pulse width of the pulse signal of the pulse power supply is less than 10ms, and the frequency of the first valve 21 to open and close continuously is 1 to 10Hz. Each time the valve core of the first valve 21 is opened, a small amount of fluid mixture in the reactor 80 is instantly introduced into the first pipeline 11 along the injection needle 50 through the cooler 60 and the first valve 21 under the huge pressure difference between the left and right sides of the valve core. In addition, by continuously opening and closing the first valve 21 for injection, the components of the fluid mixture can be evenly distributed in various places in the pipeline assembly 10.

[0053] Specifically, the method for detecting a fluid mixture comprises the following steps:

[0054] S100 , close the first valve 21 .

[0055] S210, use the vacuum pump 40 to evacuate all pipelines after the outlet end of the first valve 21, and use the first pressure sensor 71 at the inlet end 31 of the gas chromatograph 30 and the second pressure sensor 72 at the outlet end 32 to monitor the pressure (vacuum degree) in the pipeline assembly 10.

[0056] S220. Use the preheating system to heat all wet surfaces of the equipment including the first valve 21, the first pressure sensor 71, the second pressure sensor 72, the gas chromatograph 30, the first valve 21, the second valve 22, the third valve 23 and the pipeline assembly 10 (i.e., the inner surfaces of the system through which the collected fluid mixture can flow and contact) to the set preheating temperature and keep it constant.

[0057] S310, close the third valve 23 at the left outlet of the vacuum pump 40, open the first valve 21, and use a pulse power supply to drive the first valve 21 to open and close continuously at a frequency of 1 to 10 Hz with a pulse signal having a pulse width of less than 10 ms;

[0058] Each time the valve core of the first valve 21 is opened, a small amount of high-temperature and high-pressure fuel-pyrolysis product fluid mixture in the reactor 80 is instantly moved along the micro injection needle 50 under the huge pressure difference on the left and right sides of the valve core of the first valve 21, through the micro cooler 60 in front of the inlet of the first valve 21 and the valve core of the first valve 21, and enters the vacuum pipeline assembly 10. After cooling, the temperature of the fluid mixture entering the first valve 21 does not exceed 473K, so that the reaction is instantly frozen.

[0059] S320, keep the vacuum pump 40 open, adjust the opening threshold of the second valve 22 at the right outlet of the vacuum pump 40, so that the pressure of the preheating vacuum pipeline assembly 10 is an ultra-low pressure lower than the saturated vapor pressure of the sample at the corresponding temperature, and the high-pressure sample enters the pipeline assembly 10 and is flash evaporated to be in a gaseous state.

[0060] S400, the first valve 21 is continuously opened and closed for sample injection until the components of the fluid mixture are evenly distributed in the preheated vacuum pipeline assembly 10. Then the first valve 21 and the second valve 22 are closed, and after the pressure in the pipeline assembly 10 is quickly balanced by monitoring the first pressure sensor 71 and the second pressure sensor 72 before and after the online gas chromatograph 30, the online gas chromatograph 30 is started to detect the sample.

[0061] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A fluid mixture detection system, characterized in that: include: A pipeline assembly, comprising a first pipeline and a second pipeline; a first valve connected to the first pipeline, the first valve being used to control the flow of the fluid mixture obtained by the reactor reaction; A gas chromatograph, comprising an injection end and an output end, wherein the injection end is connected to an end of the first pipeline away from the first valve, and the output end is connected to the second pipeline; a vacuum pump connected to an end of the second pipeline away from the gas chromatograph; The detection system further comprises an injection needle and a cooler, wherein one end of the injection needle is used to be inserted into the reactor, and the other end is connected to the first valve, and the cooler is sleeved on the outer periphery of the injection needle; the injection needle is a micro injection needle, and the cooler is a micro cooler; The diameter and length of the micro injection needle are small enough to avoid interfering with the cracking reaction of the raw material in the reactor, and to avoid the volume in the injection needle being too large, causing the sample to be collected to reside in the injection needle for a long time.

2. The detection system according to claim 1, characterized in that: The detection system also includes a pulse power supply connected to the first valve, and the pulse power supply is used to drive the first valve to open and close.

3. The detection system according to claim 1, characterized in that: The detection system also includes a second valve arranged on the second pipeline, the second valve is located between the vacuum pump and the gas chromatograph, the second valve is a one-way valve, and the flow direction is along the second pipeline and from the gas chromatograph to the vacuum pump.

4. The detection system according to claim 3, characterized in that: The threshold pressure of the second valve is less than the saturated vapor pressure of the component corresponding to the highest boiling point value in the fluid mixture.

5. The detection system according to any one of claims 1 to 4, characterized in that: The detection system further includes a third pipeline and a third valve arranged on the third pipeline, and two ends of the third pipeline are respectively connected to the first pipeline and the second pipeline.

6. The detection system according to any one of claims 1 to 4, characterized in that: The detection system also includes a first pressure sensor arranged on the first pipeline and a second pressure sensor arranged on the second pipeline, the first pressure sensor is located between the first valve and the gas chromatograph, and the second pressure sensor is located between the vacuum pump and the gas chromatograph.

7. The detection system according to any one of claims 1 to 4, characterized in that: The detection system further comprises a heating element, and the surfaces of the first valve, the pipeline assembly and the gas chromatograph that are in contact with the fluid mixture are respectively provided with the heating element.

8. The detection system according to any one of claims 1 to 4, characterized in that: The gas chromatograph comprises at least two channels for synchronously analyzing different components, and both ends of each channel are respectively connected to the first pipeline and the second pipeline.

9. A method for detecting a fluid mixture, characterized in that: Using the detection system according to any one of claims 1 to 8, the detection method comprises the following steps: closing the first valve; Using the vacuum pump to evacuate the first pipeline, the gas chromatograph and the second pipeline; Opening the first valve to allow the fluid mixture to enter the first pipeline and flash into a gas mixture; The gas chromatograph is used to perform online detection on the gas mixture.

10. The detection method according to claim 9, characterized in that: The step of opening the first valve includes: using a pulse power supply to drive the first valve to open and close continuously; Wherein, the pulse width of the pulse signal of the pulse power supply is less than 10 ms, and the frequency of continuous opening and closing of the first valve is 1-10 Hz.

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