Microfluidic chip for generating constant micro-volume bubbles and constant micro-volume natural gas bubble combustion calorific value measuring device and method

Abstract

A microfluidic chip for generating constant micro-volume bubbles and a device and method for calculating the calorific value of combustion of constant micro-volume natural gas bubbles relate to the technical field of natural gas release and combustion testing. The purpose of the present invention is to solve the problems of low measurement accuracy and the need to burn a large amount of natural gas for measurement in existing natural gas calorific value measurement methods. The present invention measures the components of natural gas micro-bubbles through a Raman spectrometer, and then measures the calorific value data in the measurement gas cylinder through a calorific value sensor. According to the calorific value signals of the measurement gas cylinder and the reference gas cylinder collected by the signal acquisition card, the calorific value changes of the measurement gas cylinder and the reference gas cylinder are compared, and the calorific value measurement interference caused by environmental and internal factors is eliminated, and the combustion calorific value in the measurement gas cylinder is obtained. The present invention can obtain a microfluidic chip for generating constant micro-volume bubbles and a device and method for calculating the calorific value of combustion of constant micro-volume natural gas bubbles.

Description

Technical Field

[0001] The invention relates to the technical field of natural gas release and combustion testing, and in particular to a microfluidic chip for generating constant micro-volume bubbles and a device and method for calculating the combustion calorific value of constant micro-volume natural gas bubbles. Background Art

[0002] Natural gas is one of the main energy sources and is widely used in daily life and industrial production. With the development and promotion of natural gas energy measurement, accurate measurement of natural gas calorific value is the core and key work of natural gas trade settlement, and the traceability of natural gas calorific value detection equipment is the primary problem faced by technical institutions. In view of the current complex and high cost of natural gas calorific value analysis systems, it is particularly important to carry out technical research and develop natural gas calorific value detection equipment to meet the problems of online accurate measurement and traceability of natural gas calorific value, and provide technical support for the development of natural gas energy measurement.

[0003] At present, the main measurement methods for the calorific value of natural gas are direct measurement method and indirect calculation method. The direct measurement method can directly measure the calorific value of natural gas. The commonly used gas calorimeter is a water flow calorimeter. The natural gas is continuously passed through the calorimeter, and the heat generated by its combustion is continuously absorbed by the water flow. During the gas combustion time, the calorific value of the natural gas can be calculated using the amount of water passed, the temperature of the water inlet and the water outlet. However, the measurement accuracy of this direct method is not high; at the same time, the direct measurement method requires the combustion of a large amount of natural gas for measurement, which has the problems of insufficient combustion and inaccurate calorific value measurement. The indirect measurement method identifies its chemical composition through physical or chemical separation and analysis methods, and accurately determines the concentration of each component. The calorific value of the mixed gas can be accurately calculated by the formula based on the calorific value of each component. Compared with traditional natural gas measurement technology, the constant micro-volume natural gas component measurement and calorific value and carbon emission factor measurement device adopts a direct method, which can meet the requirements of component measurement, calorific value and carbon emission factor measurement of natural gas from different gas sources. In addition, the high specific surface area of ​​micro-scale natural gas bubbles can make the natural gas burn fully. The continuous combustion measurement of large sample constant natural gas bubbles can greatly improve the accuracy of measurement. Summary of the invention

[0004] The purpose of the present invention is to solve the above technical problems and to provide a microfluidic chip for generating constant micro-volume bubbles and a device and method for calculating the combustion calorific value of constant micro-volume natural gas bubbles.

[0005] A microfluidic chip, the microfluidic chip comprising a square glass tube 10, a tapered glass capillary 11, a collecting glass tube 12, a high-precision injection pump 14, an airtight injector 15, a dispensing needle 17, a gas sample cylinder 18, a constant micro-volume gas bubble storage device and a high-speed camera 23; the tapered glass capillary 11 and the collecting glass tube 12 are coaxially arranged in the square glass tube 10, and the tapered structure port of the tapered glass capillary 11 is arranged in the collecting glass tube 12, the water outlet of the dispensing needle 17 is arranged at the water inlet of the square glass tube 10, and the two ports of the square glass tube 10 are respectively sealed with the tapered glass capillary 11 and the collecting glass tube 12;

[0006] The airtight injector 15 is connected to the water inlet of the dispensing needle 17 through the pipeline a 16, and the pipeline a16 is provided with a high-precision injection pump 14; the gas sample cylinder 18 is connected to the circular structure port of the tapered glass capillary 11 through the pipeline b 21, and the water outlet of the collecting glass tube 12 is connected to the water inlet of the constant micro-volume gas bubble storage device through the pipeline c 22.

[0007] The method for generating constant micro-volume bubbles using the microfluidic chip is carried out according to the following steps:

[0008] Open the gas sample cylinder valve 20 on the pipeline b 21, and transport the gas in the gas sample cylinder 18 to the tapered glass capillary 11. At the same time, the non-flammable liquid in the airtight injector 15 is transported to the square glass tube 10 through the high-precision injection pump 14 through the dispensing needle 17. The gas and the non-flammable liquid contact at the tapered structure mouth of the tapered glass capillary 11, and merge into a constant micro-volume bubble under the action of the gas-liquid two-phase flow. The constant micro-volume bubble is then recovered into the constant micro-volume gas bubble storage device through the collecting glass tube 12. The particle size of the constant micro-volume bubble is 50 to 800 μm. The non-flammable liquid is an oily non-flammable liquid or an aqueous non-flammable liquid. The oily non-flammable liquid is dimethyl silicone oil, and the aqueous non-flammable liquid is deionized water. The high-speed camera 23 counts the diameter and number of the generated constant micro-volume gas bubbles.

[0009] A device for calculating the combustion calorific value of a constant micro-volume natural gas bubble generated by the method, the device comprising a constant micro-volume natural gas bubble storage device 1-1, a constant micro-volume nitrogen bubble storage device 1-2, a calculation gas cylinder 3, a Raman spectrometer 4, a signal acquisition card 5, a calorific value sensor a 6-1, a calorific value sensor b 6-2, a reference gas cylinder 7, an electric spark trigger 8, a high-voltage electrode a 9-1 and a high-voltage electrode b 9-2;

[0010] The water outlet of the constant micro-volume natural gas bubble storage device 1-1 is connected to the water inlet of the measuring gas cylinder 3 through a pipeline, and the detection port of the measuring gas cylinder 3 is connected to the sampling port of the Raman spectrometer 4 through a pipeline. The measuring gas cylinder 3 is provided with an oxygen inlet 303, a gas outlet 305, a calorific value sensor a 6-1, a high-voltage electrode a 9-1 and a drain outlet a 306;

[0011] The water outlet of the constant micro-volume nitrogen bubble storage device 1-2 is connected to the water inlet of the reference gas cylinder 7 through a pipeline, and the reference gas cylinder 7 is provided with a calorific value sensor b6-2, a gas outlet b703, a high-voltage electrode b9-2 and a drain outlet b704;

[0012] The signal output ends of the calorific value sensor a 6-1 and the calorific value sensor b 6-2 are both electrically connected to the signal acquisition end of the signal acquisition card 5, and the high-voltage electrode a 9-1 and the high-voltage electrode b 9-2 are both electrically connected to the electric spark trigger 8.

[0013] The method for calculating the combustion calorific value of constant micro-volume natural gas bubbles using the measuring device is carried out in the following steps:

[0014] Step 1: introduce the natural gas microbubbles 2-1 in the constant microvolume natural gas bubble storage device 1-1 into the measurement gas cylinder 3, and measure the components of the natural gas microbubbles 2-1 once by the Raman spectrometer 4; at the same time, introduce the same number and volume of nitrogen microbubbles 2-2 into the reference gas cylinder 7 by the constant microvolume nitrogen bubble storage device 1-2;

[0015] Step 2: Start the spark trigger 8 to transmit sparks to the high-voltage electrode a 9-1 and the high-voltage electrode b 9-2 respectively, ignite the natural gas microbubbles 2-1 in the measurement gas cylinder 3 through the high-voltage electrode a 9-1 and the sparks, then measure the element change curve of the natural gas microbubbles 2-1 through the Raman spectrometer 4, and perform secondary determination on the components of the natural gas microbubbles 2-1 according to the element change curve, and measure the carbon emissions of the natural gas microbubbles 2-1 per unit volume according to the C element; then measure the calorific value data in the measurement gas cylinder 3 through the calorific value sensor a 6-1, and measure the calorific value data in the reference gas cylinder 7 through the calorific value sensor b 6-2, and further compare the calorific value changes of the measurement gas cylinder 3 and the reference gas cylinder 7 according to the calorific value signals of the measurement gas cylinder 3 and the reference gas cylinder 7 collected by the signal acquisition card 5, eliminate the calorific value measurement interference caused by environmental and internal factors, and obtain the combustion calorific value in the measurement gas cylinder 3.

[0016] Beneficial effects of the present invention:

[0017] (1) The present invention constructs a microfluidic chip and utilizes gas-liquid two-phase flow technology to generate natural gas microbubbles or nitrogen microbubbles of uniform size and volume ranging from nanoliter to microliter. A high-speed photography device is used to calculate the volume of a single natural gas (or nitrogen) microbubble and the total volume of the natural gas (or nitrogen) bubbles in real time. Then, the element change curve of the natural gas microbubble is measured by a Raman spectrometer to determine its components. The calorific value data in the measurement gas cylinder is measured by a calorific value sensor. The calorific value changes of the measurement gas cylinder and the reference gas cylinder are compared based on the calorific value signals of the measurement gas cylinder and the reference gas cylinder collected by the signal acquisition card. The interference of the calorific value measurement caused by the environment and internal factors is eliminated to obtain the combustion calorific value in the measurement gas cylinder.

[0018] The present invention can save a large amount of natural gas under the same natural gas combustion test conditions, and is beneficial to improving the combustion efficiency of natural gas. At the same time, the real-time calculation based on the element and calorific value change curve of natural gas does not require excessive time consumption.

[0019] (2) The device of the present invention is simple to prepare and has low cost. It can quickly generate a large number of natural gas bubbles of constant volume. During the natural gas microbubble generation process, the microbubbles are encapsulated in a non-flammable liquid, thereby reducing the safety risks in the test process. During the measurement process, there is no direct contact between humans and natural gas, and the volume of the test natural gas is very small, thereby ensuring the safety of the measurement process and improving the overall safety.

[0020] The present invention integrates the determination of natural gas components with the calculation of calorific value and carbon emission factor, which provides convenience for the metering and measurement of natural gas. Component determination and calorific value and carbon emission factor calculation can be performed through trace amounts of natural gas, which can greatly save the consumption of the natural gas testing process and conserve natural gas resources.

[0021] The present invention can obtain a microfluidic chip for generating constant micro-volume bubbles and a device and method for calculating the combustion calorific value of constant micro-volume natural gas bubbles. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the microfluidic chip in Example 1, 10 is a square glass tube, 11 is a tapered glass capillary, 12 is a collecting glass tube, 13 is a glass slide, 14 is a high-precision injection pump, 15 is a gas-tight injector, 16 is a pipeline a, 17 is a dispensing needle, 18 is a gas sample cylinder, 19 is a gas sample cylinder pressure gauge, 20 is a gas sample cylinder valve, 21 is a pipeline b, 22 is a pipeline c, 23 is a high-speed camera, 1-1 is a constant micro-volume natural gas bubble storage device, and 1-2 is a constant micro-volume nitrogen bubble storage device;

[0023] Figure 21 is a schematic diagram of a device for calculating the combustion calorific value of a constant micro-volume natural gas bubble generated by the method described in Example 1 in Example 2, 1-1 is a constant micro-volume natural gas bubble storage device, 1-2 is a constant micro-volume nitrogen bubble storage device, 2-1 is a natural gas micro-bubble, 2-2 is a nitrogen micro-bubble, 3 is a measuring gas cylinder, 301 is a reflecting spherical mirror, 302-1 is a stop valve a, 302-2 is a stop valve b, 302-3 is a stop valve c, 303 is the oxygen inlet, 304 is the barometer a, 305 is the gas outlet a, 306 is the drain a, 4 is the Raman spectrometer, 5 is the signal acquisition card, 6-1 is the calorific value sensor a, 6-2 is the calorific value sensor b, 7 is the reference gas cylinder, 701-1 is the stop valve d, 701-2 is the stop valve e, 702 is the barometer b, 703 is the gas outlet b, 704 is the drain b, 8 is the electric spark trigger, 9-1 is the high voltage electrode a, and 9-2 is the high voltage electrode b;

[0024] Figure 3 Schematic diagram of placing a tapered glass capillary and a collecting glass tube in a square glass tube, 10 is a square glass tube, 11 is a tapered glass capillary, 12 is a collecting glass tube, and 13 is a glass slide;

[0025] Figure 4 This is a schematic diagram of the left side cut of the dispensing needle.

[0026] Figure 5 This is a schematic diagram of the right side cut of the dispensing needle.

[0027] Figure 6 This is a diagram of the process of generating constant micro-volume natural gas bubbles in a microfluidic chip.

[0028] Figure 7 Illustration of batch-controlled constant-volume natural gas bubbles generated in a microfluidic chip. DETAILED DESCRIPTION

[0029] Specific implementation method one: The microfluidic chip of this implementation method comprises a square glass tube 10, a tapered glass capillary 11, a collecting glass tube 12, a high-precision injection pump 14, an airtight injector 15, a dispensing needle 17, a gas sample cylinder 18, a constant micro-volume gas bubble storage device and a high-speed camera 23; the tapered glass capillary 11 and the collecting glass tube 12 are coaxially arranged in the square glass tube 10, and the tapered structure port of the tapered glass capillary 11 is arranged in the collecting glass tube 12, the water outlet of the dispensing needle 17 is arranged at the water inlet of the square glass tube 10, and the two ports of the square glass tube 10 are sealed with the tapered glass capillary 11 and the collecting glass tube 12 respectively;

[0030] The airtight injector 15 is connected to the water inlet of the dispensing needle 17 through the pipeline a 16, and the pipeline a16 is provided with a high-precision injection pump 14; the gas sample cylinder 18 is connected to the circular structure port of the tapered glass capillary 11 through the pipeline b 21, and the water outlet of the collecting glass tube 12 is connected to the water inlet of the constant micro-volume gas bubble storage device through the pipeline c 22.

[0031] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the square glass tube 10 is arranged on a glass slide 13.

[0032] The other steps are the same as those in the first specific implementation.

[0033] Specific implementation method three: The difference between this implementation method and specific implementation method one or two is that the constant micro-volume gas bubble storage device is a constant micro-volume natural gas bubble storage device 1-1 and a constant micro-volume nitrogen bubble storage device 1-2.

[0034] The other steps are the same as those in the first or second embodiment.

[0035] Specific implementation method 4: This implementation method uses the microfluidic chip to generate constant micro-volume bubbles, and is carried out according to the following steps:

[0036] Open the gas sample cylinder valve 20 on the pipeline b 21, and transport the gas in the gas sample cylinder 18 to the tapered glass capillary 11. At the same time, the non-flammable liquid in the airtight injector 15 is transported to the square glass tube 10 through the high-precision injection pump 14 through the dispensing needle 17. The gas and the non-flammable liquid contact at the tapered structure mouth of the tapered glass capillary 11, and merge into a constant micro-volume bubble under the action of the gas-liquid two-phase flow. The constant micro-volume bubble is then recovered into the constant micro-volume gas bubble storage device through the collecting glass tube 12. The particle size of the constant micro-volume bubble is 50 to 800 μm. The non-flammable liquid is an oily non-flammable liquid or an aqueous non-flammable liquid. The oily non-flammable liquid is dimethyl silicone oil, and the aqueous non-flammable liquid is deionized water. The high-speed camera 23 counts the diameter and number of the generated constant micro-volume gas bubbles.

[0037] Specific implementation method five: This implementation method is different from specific implementation method four in that: the gas is natural gas or nitrogen.

[0038] The other steps are the same as those in the fourth embodiment.

[0039] Specific embodiment six: The difference between this embodiment and specific embodiment four or five is that the constant micro-volume gas bubble storage device is a constant micro-volume natural gas bubble storage device 1-1 or a constant micro-volume nitrogen bubble storage device 1-2.

[0040] The other steps are the same as those in the fourth or fifth embodiment.

[0041] Specific implementation method seven: This implementation method is based on a device for calculating the combustion calorific value of a constant micro-volume natural gas bubble generated by the method, and the device for calculating the combustion calorific value of a constant micro-volume natural gas bubble comprises a constant micro-volume natural gas bubble storage device 1-1, a constant micro-volume nitrogen bubble storage device 1-2, a measuring gas cylinder 3, a Raman spectrometer 4, a signal acquisition card 5, a calorific value sensor a 6-1, a calorific value sensor b 6-2, a reference gas cylinder 7, an electric spark trigger 8, a high-voltage electrode a 9-1 and a high-voltage electrode b 9-2;

[0042] The water outlet of the constant micro-volume natural gas bubble storage device 1-1 is connected to the water inlet of the measuring gas cylinder 3 through a pipeline, and the detection port of the measuring gas cylinder 3 is connected to the sampling port of the Raman spectrometer 4 through a pipeline. The measuring gas cylinder 3 is provided with an oxygen inlet 303, a gas outlet 305, a calorific value sensor a 6-1, a high-voltage electrode a 9-1 and a drain outlet a 306;

[0043] The water outlet of the constant micro-volume nitrogen bubble storage device 1-2 is connected to the water inlet of the reference gas cylinder 7 through a pipeline, and the reference gas cylinder 7 is provided with a calorific value sensor b6-2, a gas outlet b703, a high-voltage electrode b9-2 and a drain outlet b704;

[0044] The signal output ends of the calorific value sensor a 6-1 and the calorific value sensor b 6-2 are both electrically connected to the signal acquisition end of the signal acquisition card 5, and the high-voltage electrode a 9-1 and the high-voltage electrode b 9-2 are both electrically connected to the electric spark trigger 8.

[0045] Specific embodiment eight: The difference between this embodiment and specific embodiment seven is that: the measuring gas cylinder 3 is provided with a pressure gauge a 304, the pipeline of the oxygen inlet 303 is provided with a stop valve a 302-1, the pipeline of the gas outlet 305 is provided with a stop valve b 302-2, and the pipeline of the drain outlet a 306 is provided with a stop valve c 302-3.

[0046] The other steps are the same as those in the seventh embodiment.

[0047] Specific implementation method nine: The difference between this implementation method and specific implementation method seven or eight is that: the reference gas cylinder 7 is provided with a pressure gauge b 702, the pipeline of the gas outlet b 703 is provided with a stop valve d 701-1, and the pipeline of the drain outlet b 704 is provided with a stop valve e 701-2.

[0048] The other steps are the same as those in Specific Embodiment 7 or 8.

[0049] Specific implementation method 10: This implementation method uses the above-mentioned measuring device to measure the constant micro-volume natural gas bubble combustion calorific value, and is carried out according to the following steps:

[0050] Step 1: introduce the natural gas microbubbles 2-1 in the constant microvolume natural gas bubble storage device 1-1 into the measurement gas cylinder 3, and measure the components of the natural gas microbubbles 2-1 once by the Raman spectrometer 4; at the same time, introduce the same number and volume of nitrogen microbubbles 2-2 into the reference gas cylinder 7 by the constant microvolume nitrogen bubble storage device 1-2;

[0051] Step 2: Start the spark trigger 8 to transmit sparks to the high-voltage electrode a 9-1 and the high-voltage electrode b 9-2 respectively, ignite the natural gas microbubbles 2-1 in the measurement gas cylinder 3 through the high-voltage electrode a 9-1 and the sparks, then measure the element change curve of the natural gas microbubbles 2-1 through the Raman spectrometer 4, and perform secondary determination on the components of the natural gas microbubbles 2-1 according to the element change curve, and measure the carbon emissions of the natural gas microbubbles 2-1 per unit volume according to the C element; then measure the calorific value data in the measurement gas cylinder 3 through the calorific value sensor a 6-1, and measure the calorific value data in the reference gas cylinder 7 through the calorific value sensor b 6-2, and further compare the calorific value changes of the measurement gas cylinder 3 and the reference gas cylinder 7 according to the calorific value signals of the measurement gas cylinder 3 and the reference gas cylinder 7 collected by the signal acquisition card 5, eliminate the calorific value measurement interference caused by environmental and internal factors, and obtain the combustion calorific value in the measurement gas cylinder 3.

[0052] The following examples are used to verify the beneficial effects of the present invention:

[0053] Embodiment 1: A microfluidic chip, which comprises a square glass tube 10, a tapered glass capillary 11, a collecting glass tube 12, a high-precision injection pump 14, an airtight injector 15, a dispensing needle 17, a gas sample cylinder 18, a constant micro-volume gas bubble storage device and a high-speed camera 23; the tapered glass capillary 11 and the collecting glass tube 12 are coaxially arranged in the square glass tube 10, and the tapered structure mouth of the tapered glass capillary 11 is arranged in the collecting glass tube 12, the water outlet of the dispensing needle 17 is arranged at the water inlet of the square glass tube 10, and is sealed with transparent epoxy resin glue, and the square glass tube 10 is arranged on a glass slide 13.

[0054] The airtight injector 15 is connected to the water inlet of the dispensing needle 17 through the pipeline a 16, and the pipeline a 16 is provided with a high-precision injection pump 14; the gas sample cylinder 18 is connected to the circular structure port of the tapered glass capillary 11 through the pipeline b 21, and the water outlet of the collecting glass tube 12 is connected to the water inlet of the constant micro-volume gas bubble storage device through the pipeline c 22, and the square glass tube 10 where the water outlet of the collecting glass tube 12 is located is directly sealed with transparent epoxy resin glue; the constant micro-volume gas bubble storage device is a constant micro-volume natural gas bubble storage device 1-1 or a constant micro-volume nitrogen bubble storage device 1-2.

[0055] The cross section of the square glass tube 10 is a square with an outer side length of 1.5 mm*1.5 mm and a square glass microchannel with an inner side length of 1.05 mm*1.05 mm.

[0056] The tapered glass capillary 11 is a circular glass tube with an outer diameter of 1.03 mm and an inner diameter of 0.58 mm, which is tapered and fractured by a needle forging instrument, and the fracture size is 20-80 μm, which can be processed according to the actual gas microbubble size requirements.

[0057] The collecting glass tube 12 is a circular glass tube with an outer diameter of 1.03 mm and an inner diameter of 0.58 mm.

[0058] Square cuts of 1.05 mm*1.05 mm and 1.5 mm*1.5 mm are made on both sides of the dispensing needle 17 respectively.

[0059] The method for generating constant micro-volume bubbles using the microfluidic chip is carried out according to the following steps:

[0060] Open the gas sample cylinder valve 20 on the pipeline b 21, and transport the gas in the gas sample cylinder 18 to the tapered glass capillary 11. At the same time, the non-flammable liquid in the airtight injector 15 is transported to the square glass tube 10 through the high-precision injection pump 14 through the dispensing needle 17. The gas and the non-flammable liquid contact at the tapered structure mouth of the tapered glass capillary 11, and merge into a constant micro-volume bubble under the action of the gas-liquid two-phase flow. The constant micro-volume bubble is then recovered into the constant micro-volume gas bubble storage device through the collecting glass tube 12. The particle size of the constant micro-volume bubble is 50 to 800 μm. The non-flammable liquid is an oily non-flammable liquid or an aqueous non-flammable liquid. The oily non-flammable liquid is dimethyl silicone oil, and the aqueous non-flammable liquid is deionized water. The high-speed camera 23 counts the diameter and number of the generated constant micro-volume gas bubbles.

[0061] The gas is natural gas or nitrogen, and the constant micro-volume natural gas bubbles are recovered into the constant micro-volume natural gas bubble storage device 1-1, and the constant micro-volume nitrogen bubbles are recovered into the constant micro-volume nitrogen bubble storage device 1-2.

[0062] Gas and non-flammable liquid are input simultaneously, and the gas generates micro-volume gas microbubbles under the shear force of the liquid. The generation efficiency and volume of the gas microbubbles can be controlled by adjusting the liquid flow rate and the pressure of the gas sample cylinder 18. A high-speed camera is provided above the square glass tube to count the diameter and number of the generated gas microbubbles, so as to calculate the total volume of the gas microbubbles generated by the device.

[0063] Embodiment 2: A device for calculating the calorific value of combustion of a constant micro-volume natural gas bubble generated by the method described in Embodiment 1, the device comprising a constant micro-volume natural gas bubble storage device 1-1, a constant micro-volume nitrogen bubble storage device 1-2, a measuring gas cylinder 3, a Raman spectrometer 4, a signal acquisition card 5, a calorific value sensor a 6-1, a calorific value sensor b 6-2, a reference gas cylinder 7, an electric spark trigger 8, a high-voltage electrode a 9-1 and a high-voltage electrode b 9-2;

[0064] The water outlet of the constant micro-volume natural gas bubble storage device 1-1 is connected to the water inlet of the measuring gas cylinder 3 through a pipeline, and the detection port of the measuring gas cylinder 3 is connected to the sampling port of the Raman spectrometer 4 through a pipeline. The measuring gas cylinder 3 is provided with an oxygen inlet 303, a gas outlet 305, a calorific value sensor a 6-1, a high-voltage electrode a 9-1 and a drain outlet a 306; the measuring gas cylinder 3 is provided with a pressure gauge a 304, a stop valve a 302-1 is provided on the pipeline of the oxygen inlet 303, a stop valve b 302-2 is provided on the pipeline of the gas outlet 305, and a stop valve c 302-3 is provided on the pipeline of the drain outlet a 306.

[0065] The water outlet of the constant micro-volume nitrogen bubble storage device 1-2 is connected to the water inlet of the reference gas cylinder 7 through a pipeline, and the reference gas cylinder 7 is provided with a calorific value sensor b6-2, a gas outlet b703, a high-voltage electrode b9-2 and a drain outlet b704; the reference gas cylinder 7 is provided with a pressure gauge b702, a stop valve d701-1 is provided on the pipeline of the gas outlet b703, and a stop valve e701-2 is provided on the pipeline of the drain outlet b704.

[0066] The signal output ends of the calorific value sensor a 6-1 and the calorific value sensor b 6-2 are both electrically connected to the signal acquisition end of the signal acquisition card 5, and the high-voltage electrode a 9-1 and the high-voltage electrode b 9-2 are both electrically connected to the electric spark trigger 8.

[0067] The method for calculating the combustion calorific value of constant micro-volume natural gas bubbles using the measuring device is carried out in the following steps:

[0068] Step 1: introduce the natural gas microbubbles 2-1 in the constant micro-volume natural gas bubble storage device 1-1 into the measuring gas cylinder 3, and continuously detect the gradient of each element in the measuring gas cylinder 3 through the Raman spectrometer 4. According to the gradient of each element such as C, H and O, the components of the natural gas microbubbles 2-1 are measured once; at the same time, introduce the same number and volume of nitrogen microbubbles 2-2 into the reference gas cylinder 7 through the constant micro-volume nitrogen bubble storage device 1-2; the real-time total volume of natural gas entering the measuring gas cylinder 3 can be calculated according to the diameter and number of the natural gas microbubbles, and the same is true for the nitrogen entering the reference gas cylinder 7;

[0069] Step 2: Start the spark trigger 8 to transmit sparks to the high-voltage electrode a 9-1 and the high-voltage electrode b 9-2 respectively, ignite the natural gas microbubbles 2-1 in the measurement gas cylinder 3 through the high-voltage electrode a 9-1 and the sparks, then measure the element change curve of the natural gas microbubbles 2-1 through the Raman spectrometer 4, and perform secondary determination on the components of the natural gas microbubbles 2-1 according to the element change curve, and measure the carbon emissions of the natural gas microbubbles 2-1 per unit volume according to the C element; then measure the calorific value data in the measurement gas cylinder 3 through the calorific value sensor a 6-1, and measure the calorific value data in the reference gas cylinder 7 through the calorific value sensor b 6-2, and further compare the calorific value changes of the measurement gas cylinder 3 and the reference gas cylinder 7 according to the calorific value signals of the measurement gas cylinder 3 and the reference gas cylinder 7 collected by the signal acquisition card 5, eliminate the calorific value measurement interference caused by environmental and internal factors, and obtain the combustion calorific value in the measurement gas cylinder 3.

Claims

1. Microfluidic chip, It is characterized in that The microfluidic chip comprises a square glass tube (10), a conical glass capillary (11), a collecting glass tube (12), a high-precision injection pump (14), a gas-tight injector (15), a dispensing needle (17), a gas sample cylinder (18), a constant micro-volume gas bubble storage device and a high-speed camera (23); the conical glass capillary (11) and the collecting glass tube (12) are coaxially arranged in the square glass tube (10), and the conical structure port of the conical glass capillary (11) is arranged in the collecting glass tube (12), the water outlet of the dispensing needle (17) is arranged at the water inlet of the square glass tube (10), and the two ports of the square glass tube (10) are respectively sealed with the conical glass capillary (11) and the collecting glass tube (12); The airtight injector (15) is connected to the water inlet of the dispensing needle (17) through the pipeline a (16), and a high-precision injection pump (14) is provided on the pipeline a (16); the gas sample cylinder (18) is connected to the circular structure port of the tapered glass capillary (11) through the pipeline b (21), and the water outlet of the collecting glass tube (12) is connected to the water inlet of the constant micro-volume gas bubble storage device through the pipeline c (22); The constant micro-volume gas bubble storage device is a constant micro-volume natural gas bubble storage device (1-1) and a constant micro-volume nitrogen bubble storage device (1-2).

2. The microfluidic chip according to claim 1, It is characterized in that The square glass tube (10) is arranged on a glass slide (13).

3. A method for generating constant microvolume bubbles using a microfluidic chip as described in any one of claims 1 to 2, It is characterized in that The method proceeds as follows: The valve (20) of the gas sample cylinder on the pipeline b (21) is opened to transport the gas in the gas sample cylinder (18) into the conical glass capillary (11). At the same time, the non-flammable liquid in the gas-tight injector (15) is transported into the square glass tube (10) through the dispensing needle (17) by the high-precision injection pump (14). The gas and the non-flammable liquid contact at the conical structure mouth of the conical glass capillary (11) and merge into constant micro-volume bubbles under the action of the gas-liquid two-phase flow. The constant micro-volume bubbles are then recovered into the constant micro-volume gas bubble storage device through the collecting glass tube (12). The particle size of the constant micro-volume bubbles is 50-800 μm. The non-flammable liquid is an oily non-flammable liquid or an aqueous non-flammable liquid. The oily non-flammable liquid is dimethyl silicone oil and the aqueous non-flammable liquid is deionized water. The high-speed camera (23) counts the diameter and number of the generated constant micro-volume gas bubbles.

4. The method according to claim 3, It is characterized in that The gas is natural gas or nitrogen.

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