Device and method for testing limit oxygen concentration of combustible liquid

Abstract

The invention discloses a combustible liquid limit oxygen concentration testing device and method, and the device comprises an electrolyte supply system which comprises a height-adjustable placement platform and a constant-pressure liquid supply module; the combustion system comprises a base and a combustion tube, a partition plate is fixedly connected to the middle position in the combustion tube, an ignition module is detachably connected to the center position of the top face of the partition plate, a lampwick tube is arranged in the ignition module, a lampwick is arranged at the top end of the lampwick tube, and rectification modules are arranged on the top face of the partition plate and the inner bottom of the combustion tube correspondingly; an experimental darkroom is mounted on the top surface of the base; a gas inlet pipe is mounted at the bottom of the combustion pipe; the gas distribution system is connected with the control system; the optical measurement and analysis system is mounted in the experimental darkroom; a waste liquid recovery module is installed at the bottom of the base. A discharge pipe is installed at the bottom of the combustion pipe. The constant-pressure liquid supply module can ensure that electrolyte with stable pressure is provided for the lampwick tube, and the accuracy and repeatability of a test result are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of limiting oxygen concentration testing, and particularly to a testing device and method for the limiting oxygen concentration of combustible liquids. Background Art

[0002] The flammability evaluation indexes of single-component liquids usually include the upper or lower flammability limit (UFL / LFL), flash point (FP), autoignition temperature (AIT), heat of combustion (∆Hc), etc. However, it is very difficult to quantitatively characterize the flammability of multi-component mixed liquids through the above characteristics. For mixed liquid samples with specific ratios such as battery organic electrolyte solvents, existing research usually uses the self-extinguishing time (SET) to evaluate their flammability, or adopts a linear flame propagation test modified based on ASTM D5306 standard or a flame extinction probability test for evaluation. Most self-extinguishing time experiments (SET) directly ignite the solvent or the solvent-dipped object by an open flame method, and the results are greatly affected by the ignition source and liquid volatilization. The latter two methods can only give qualitative analysis results (flammable, difficult to burn, and non-flammable in three grades) due to uncertain experimental conditions.

[0003] The limiting oxygen concentration at which a material ignites or extinguishes can become a key index for evaluating the flammability of gaseous fuels, volatile solvents, and solid materials. In order to conduct quantitative analysis of the flammability limit of combustible mixed solutions, especially for lithium-ion battery electrolytes composed of multiple chemical components (solvents, additives, and lithium salts) in specific proportions, the limiting oxygen concentration is a more suitable evaluation criterion for quantifying its flammability. Different flash points are parameters related to the physical properties of combustible liquid evaporation, and the limiting oxygen concentration of material combustion is more related to the chemical properties in the combustion reaction of combustible liquids. If the oxygen concentration can be controlled below these limits, fuel combustion can be prevented; at the same time, combustible liquids with higher limiting oxygen concentration values also prove to have better flame retardant effects. In addition, from the perspective of combustion testing methods, for the combustion of electrolytes involving the evaporation and decomposition of multi-component fuels, a simple non-premixed flame system is more conducive to intuitive observation and continuous repeated experiments. Therefore, we call the lowest air oxygen concentration that maintains continuous combustion of combustibles the limiting oxygen index.

[0004] Existing limiting oxygen index measurement devices are based on the ISO4589 standard, mainly used for measuring the limiting oxygen index of flat and rod-shaped solid materials, and mostly use specimen clamps to hold the object to be measured. For liquids, small discs or small cups are mostly used to directly ignite, and this measurement method is greatly affected by the volatilization of liquids. Moreover, for mixed liquids, the concentration of high-boiling components will gradually increase due to the distillation effect, which is not conducive to accurate quantitative analysis.

[0005] Different from the combustion of solids and gases, when liquids burn, the stable supply of fuel is more difficult and important (especially in experiments mainly based on diffusion combustion). During current tests, the limiting oxygen concentration data measured by first placing the liquid fuel to be tested in a container such as a small cup and igniting it is easily affected by factors such as thermal radiation feedback, adhesion of high-viscosity components, and selective volatilization of low-boiling components, resulting in inaccurate measurement results. At the same time, the limitation of the quantity of a single portion of fuel makes it impossible to continuously conduct combustion experiments, and it is difficult to guarantee the data accuracy and repeatability. Existing oxygen index meters usually discard the experimental materials after one experiment, with poor economy and harm to the environment, which is worthy of improvement. In addition, the wick combustion method used in previous paper experiments is also affected by radiative heat feedback.

[0006] Obtaining an accurate oxygen index requires stable environmental conditions. Although traditional limiting oxygen index meters will determine the axial flow rate, the specific value is approximately 5 cm / s and will not change the axial flow rate of the gas. This instrument provides a variable axial flow rate, and the flow field is difficult to analyze, resulting in difficulties in studying the flame extinction mechanism. For other types of traditional limiting oxygen index analyzers, usually only a specific oxygen index value can be obtained, and it is impossible to deeply analyze the data in combination with phenomena, including further analysis in connection with specific flame phenomena, parameters such as the rectified flow field velocity, etc.

[0007] Based on the above technical problems, the present invention provides a test device and method for the limiting oxygen concentration of combustible liquids. Summary of the Invention

[0008] The purpose of the present invention is to provide a test device and method for the limiting oxygen concentration of combustible liquids to solve the problems existing in the prior art.

[0009] To achieve the above purpose, the present invention provides the following solution: The present invention provides a test device for the limiting oxygen concentration of combustible liquids, including: An electrolyte supply system, the electrolyte supply system includes an adjustable-height placement platform and a constant-pressure liquid supply module; A combustion system, the combustion system includes a base and a combustion tube. The bottom of the combustion tube is fixedly connected with a partition plate, and a plurality of through holes are opened on the partition plate. The ignition module is detachably connected to the center position of the top surface of the partition plate. A wick tube is arranged inside the ignition module, and a wick is provided at the top end of the wick tube. The constant-pressure liquid supply module is connected to the wick tube; an experimental darkroom is installed on the top surface of the base; A gas rectification chamber, the gas rectification chamber is installed on the base, and a rectification module is arranged inside the gas rectification chamber; A gas distribution system, an air inlet pipe is installed at the bottom of the gas rectification chamber, and the output end of the gas distribution system is connected to one end of the air inlet pipe; A control system, the gas distribution system is connected to the control system; An optical measurement and analysis system, the optical measurement and analysis system is installed in the experimental darkroom, and the optical measurement and analysis system is connected to the terminal system; Wherein, a waste liquid recovery module is installed at the bottom of the base.

[0010] According to the flammable liquid limiting oxygen concentration test device provided by the present invention, the adjustable height placement platform includes: Vertical frames, there are two groups of vertical frames, and the two groups of vertical frames are arranged in parallel; Sliding tables, sliding tables are respectively vertically slidably connected to the vertical frames; Positioning components, the positioning components include positioning bolts, positioning holes are opened on the side of the sliding table, the positioning bolts are threadedly connected in the positioning holes, and the positioning bolts are abutted against the vertical frames; Wherein, scale lines are provided on the vertical frames.

[0011] According to the flammable liquid limiting oxygen concentration test device provided by the present invention, the constant pressure liquid supply module includes: A liquid storage tank, the liquid storage tank is placed on one of the adjustable height placement platforms; A liquid level control tank, the liquid level control tank is placed on the other adjustable height placement platform; A switchable funnel, the switchable funnel is vertically inserted into the pipe orifice of the liquid storage tank; A liquid outlet pipe, the liquid outlet pipe is fixed at the bottom end on the side of the liquid storage tank, one end of the liquid outlet pipe is inserted into the liquid level control tank, and a control valve I is installed on the liquid outlet pipe; A constant pressure pipe, one end of the constant pressure pipe is inserted into the liquid storage tank, and the other end of the constant pressure pipe is inserted into the liquid level control tank; Wherein, the liquid level control tank is connected to the wick tube through a delivery pipe, one end of the delivery pipe is fixed at the bottom end on the side of the liquid level control tank, and a control valve II is installed on the delivery pipe.

[0012] According to the flammable liquid limiting oxygen concentration test device provided by the present invention, the ignition module includes: A combustion base, the combustion base is fixed at the center position on the top surface of the partition board, and the wick tube is fixed on the top surface of the combustion base; A fixed sleeve, the fixed sleeve is threadedly connected to the combustion base, and a through hole is opened at the center position of the top of the fixed sleeve; A heat insulation sleeve, the heat insulation sleeve is coaxially arranged inside the fixed sleeve; A heating wire, the heating wire is arranged on the inner wall of the heat insulation sleeve; An atomizer, the atomizer is installed on the inner top wall of the fixed sleeve, and the atomizer is arranged corresponding to the through hole.

[0013] According to the flammable liquid limiting oxygen concentration test device provided by the present invention, the rectification module includes: A glass bead rectification layer, the glass bead rectification layer is laid on the bottom of the gas rectification chamber; A honeycomb hole plate layer I, the honeycomb hole plate layer I is arranged above the glass bead rectification layer; A honeycomb hole plate layer II, the honeycomb hole plate layer II is arranged on the top surface of the partition plate.

[0014] According to the flammable liquid limiting oxygen concentration test device provided by the present invention, the gas distribution system includes: Gas storage tanks, several groups of the gas storage tanks are provided; A gas mixing tank, several of the gas storage tanks are all connected to the gas mixing tank through pipelines; Flow meters, the flow meters are respectively arranged on several groups of the pipelines; Wherein, one end of the air inlet pipe is connected to the gas mixing tank, and an air supply pump is installed on the air inlet pipe.

[0015] According to the flammable liquid limiting oxygen concentration test device provided by the present invention, the optical measurement and analysis system includes: A camera, the camera is installed in the experimental darkroom through a support frame; An optical fiber probe, the optical fiber probe is installed on the side wall of the darkroom, and the optical fiber probe is connected to a micro spectrometer; A sheet light source emitter, the sheet light source emitter is installed in the darkroom.

[0016] According to the flammable liquid limiting oxygen concentration test device provided by the present invention, the waste liquid recovery module includes: A recovery bottle, the recovery bottle is placed on the base, and the recovery bottle is located below the gas rectification chamber; A discharge pipe is installed at the bottom of the gas rectification chamber, and the discharge pipe is arranged corresponding to the recovery bottle A control valve III, the control valve III is installed on the discharge pipe.

[0017] A method for testing the limiting oxygen concentration of a flammable liquid, comprising the following steps: Step 1, assemble the experimental device, pre-soak the wick, and insert the wick into the top end of the wick tube after the wick meets the experimental requirements; Step 2, inject the experimental liquid into the constant pressure liquid supply module, open the constant pressure liquid supply module until the liquid fills the delivery pipe and there is no air residue, and check that the upper end of the wick is moist; Step 3: The gas distribution system works. The control system controls the gas distribution concentration, gas flow rate and flow volume. The mixed gas is input into the gas rectification chamber, and uniform gas distribution is achieved through the rectification module. Then, it enters the combustion tube through the partition board. Step 4: Use an igniter to ignite the atomized droplets to obtain a stable flame, and judge the stability of the flame through an optical measurement and analysis system. Step 5: After judging that the flame and flow rate are stable, the test of the limiting oxygen index can be started. A method similar to the dichotomy is used to determine the limiting oxygen index of liquid fuels such as electrolytes. In the first experiment, each time it is reduced by 5% vol. According to the replacement time of the new mixed gas in the gas supply system, the test duration under given conditions is at least one minute. If the flame continues to burn for more than one minute, it is judged as the "continuous combustion" state, and oxygen needs to be further reduced. Otherwise, if the flame goes out within one minute, it is judged as the "extinguished" state. After initially obtaining the approximate range of the oxygen index, in the second experiment, it can be directly reduced from the initial high concentration to near the upper limit of the oxygen concentration obtained in the first experiment, and each time the oxygen concentration is reduced by 1% vol to obtain a more accurate oxygen concentration range. And so on, in the third and subsequent experiments, each time the oxygen concentration is reduced by 0.1% vol to obtain the limiting oxygen index of liquid atomization combustion. Repeat the experiment multiple times and take the average value to obtain the limiting oxygen index value range.

[0018] The present invention discloses the following technical effects: 1) The constant-pressure liquid supply module can ensure that the electrolyte with a stable pressure is provided for the wick tube, avoid the instability of the electrolyte flow rate caused by the fluctuation of the liquid supply pressure, and thus affect the combustion process of the combustible liquid, and ensure the accuracy and repeatability of the test results.

[0019] 2) The adjustable-height placement platform can adjust the height of the constant-pressure liquid supply module according to actual needs, which is convenient for adapting and installing with other components such as the combustion system, improves the flexibility and versatility of the device, and is convenient for reasonable layout in different experimental scenarios.

[0020] 3) The detachable ignition module is convenient for installation, replacement and maintenance, ensuring the reliability and stability of the ignition process. The cooperation between the wick tube and the wick can accurately control the ignition position and combustion state of the combustible liquid.

[0021] 4) The partition top surface and the rectification module in the gas rectification chamber can rectify the air flow entering the combustion tube, make the gas flow more uniform and stable, reduce the influence of turbulence and eddy current on the combustion process, improve the combustion efficiency, ensure the stability and consistency of the combustion process, and is conducive to accurately measuring the limiting oxygen concentration of the combustible liquid.

[0022] 5) The experimental darkroom provides a good working environment for the optical measurement and analysis system, avoiding external light interference, ensuring that the optical measurement and analysis system can accurately capture and analyze the optical signals during the combustion process, and improving the measurement accuracy and reliability.

[0023] 6) The gas distribution system is connected to the control system, which can accurately control the ratio of oxygen and other gases entering the combustion tube, meet the requirements of different flammable liquid limiting oxygen concentration tests, and realize the accurate study of the combustion characteristics of flammable liquids in different oxygen concentration environments.

[0024] 7) Through the integrated control of the gas distribution system by the control system, the automation and intelligence of gas ratio are realized, the convenience and accuracy of experimental operation are improved, and the influence of human factors on experimental results is reduced.

[0025] 8) The optical measurement and analysis system installed in the experimental darkroom can collect the optical signals during the combustion process in real time and accurately, such as flame color, brightness, spectrum, etc., and transmit the collected data to the terminal system for analysis and processing, providing rich data support for the study of the combustion mechanism and limiting oxygen concentration of flammable liquids.

[0026] 9) The terminal system can deeply analyze the data collected by the optical measurement and analysis system. By establishing mathematical models and algorithms, it can accurately calculate the limiting oxygen concentration of flammable liquids, and simulate and predict the combustion process, providing a scientific basis for the safe use of flammable liquids and fire prevention and control.

[0027] 10) The waste liquid recovery module installed at the bottom of the base and the discharge pipe corresponding to the gas rectification chamber can collect and recover the waste liquid generated during the combustion process in a timely and effective manner, avoid environmental pollution caused by the waste liquid, and also reduce the safety risks during the experiment, meeting the environmental protection and safety requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0029] Figure 1 is a schematic structural diagram of the flammable liquid limiting oxygen concentration test device of the present invention; Figure 2 is the front view of the combustion system of the present invention; Figure 3 is the axonometric view of the combustion system of the present invention; Figure 4 is the axonometric view of the ignition module of the present invention; Figure 5 Isometric view of the ignition module of the present invention; Figure 6 Front view of the ignition module of the present invention; Figure 7 Schematic structural view of the base of the present invention.

[0030] Wherein, 1, electrolyte supply system; 2, combustion system; 3, gas distribution system; 4, optical measurement and analysis system; 5, waste liquid recovery module; 101, vertical frame; 102, sliding table; 103, positioning bolt; 111, liquid storage tank; 112, liquid level control tank; 113, switchable funnel; 114, liquid outlet pipe; 115, control valve I; 116, constant pressure pipe; 117, delivery pipe; 118, control valve II; 201, combustion base; 202, fixed sleeve; 203, heat insulation sleeve; 204, heating wire; 205, atomizer; 211, wick tube; 212, wick; 221, glass bead rectification layer; 222, honeycomb orifice plate layer I; 223, honeycomb orifice plate layer II; 231, base; 232, combustion tube; 233, partition; 241, gas rectification chamber; 301, gas storage tank; 302, gas mixing tank; 303, flow meter; 401, camera; 402, optical fiber probe; 403, sheet light source emitter; 501, recovery bottle; 502, control valve III. Specific embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0033] Referring to Figure 1-7 , the present invention provides a flammable liquid limiting oxygen concentration test device, including: An electrolyte supply system 1, the electrolyte supply system 1 includes an adjustable height placement platform and a constant pressure liquid supply module, and the constant pressure liquid supply module is placed on the adjustable height placement platform; Combustion system 2, the combustion system 2 includes a base 231 and a combustion tube 232. The combustion tube 232 is vertically detachably connected to the top surface of the base 231. A partition 233 is fixedly connected to the bottom of the combustion tube 232. A number of through holes are provided on the partition 233. An ignition module is detachably connected to the central position of the top surface of the partition 233. A wick tube 211 is provided inside the ignition module. A wick 212 is provided at the top end of the wick tube 211. The output end of the constant pressure liquid supply module is connected to the bottom end of the wick tube 211 through a delivery pipe 117; An experimental darkroom is installed on the top surface of the base 231; In order to prevent the poor temporary absorption of liquid by the wick 212, the wick 212 made of various materials such as cotton, fiberglass, and porous ceramics can be soaked for 24 hours first; The combustion tube 232 can be made of glass or acrylic. The inner diameter of the glass barrel is 100 mm, the tube length is 220 mm, and a 5 mm hole is provided at the position corresponding to the optical fiber probe 402 above the wick 212 on the barrel.

[0034] The outer diameter of the wick tube 211 is 12 mm, the inner diameter is 6 mm, and the height is 30 mm. A heating wire 204 attachment groove is provided on the outer wall, and the heating wire 204 can be used for heating.

[0035] Gas rectification chamber 241, the gas rectification chamber 241 is installed on the base 231 and is located below the combustion tube 232. A rectification module is provided inside the gas rectification chamber 241; Gas distribution system 3, an intake pipe is installed at the bottom of the gas rectification chamber 241. The output end of the gas distribution system 3 is connected to one end of the intake pipe; Control system, the gas distribution system 3 is connected to the control system; Optical measurement and analysis system 4, the optical measurement and analysis system 4 is installed in the experimental darkroom, and the optical measurement and analysis system 4 is connected to the terminal system; Among them, a waste liquid recovery module 5 is installed at the bottom of the base 231. A discharge pipe is installed at the bottom of the gas rectification chamber 241, and the discharge pipe is arranged corresponding to the waste liquid recovery module 5.

[0036] Considering factors such as the volatility and certain corrosiveness of the experimental liquid, improving the service life of the experimental device and facilitating cleaning, the base 231 is made of 304 stainless steel, with dimensions of approximately 350 mm Χ 350 mm Χ 180 mm. The front of the base 231 is made into a lockable structure that can be opened and closed to facilitate the placement and removal of the recovery bottle 501, waste liquid collection, and internal cleaning. Rubber feet are provided at the bottom to provide support and have a certain anti-vibration interference effect.

[0037] The control system adopts a self-designed standard electrical control cabinet. The electrical control cabinet uses a metal frame structure and is built-in with control software, which can realize equipment power supply and function control. Electrical control function components are installed inside the electrical control cabinet. The system uses a programmable logic controller and an analog quantity module to realize test data acquisition and action control. The operation software is mainly used to set and display the gas flow rate and oxygen concentration, and record test data such as flow rate, oxygen concentration and other parameters. It has the functions of data curve display and storage.

[0038] The oxygen concentration configuration and supply system is a device that consists of a programmable logic controller equipped with an analog quantity module, mass flow controllers for oxygen and nitrogen, and a gas mixing tank 302, and automatically configures the corresponding oxygen concentration through the setting of the upper computer.

[0039] The wick 212 is a cotton wick or a fiberglass wick with a diameter of 5 mm.

[0040] Among them, the gas flow rate is adjustable from 5 to 20 cm / s, and the oxygen concentration is adjustable from 0 to 100%.

[0041] When the inner diameter of the combustion tube 232 is fixed at 80 mm: The total gas flow rate corresponding to a gas flow rate of 5 cm / s is: 15.12 L / min; The total gas flow rate corresponding to a gas flow rate of 10 cm / s is: 30.24 L / min; The total gas flow rate corresponding to a gas flow rate of 20 cm / s is: 60.48 L / min; The measuring range of the mass flow controller is 65 L / min; For a further optimized solution, the adjustable-height placement platform includes: Vertical frames 101, two groups of vertical frames 101 are provided, and the two groups of vertical frames 101 are arranged in parallel; Sliding tables 102, and the sliding tables 102 are respectively connected to the vertical frames 101 in a vertically sliding manner; A positioning component, the positioning component includes a positioning bolt 103, a positioning hole is opened on the side of the sliding table 102, the positioning bolt 103 is threadedly connected in the positioning hole, and the positioning bolt 103 abuts against the vertical frame 101; Among them, scale lines are provided on the vertical frame 101.

[0042] For a further optimized solution, the constant-pressure liquid supply module includes: A liquid storage tank 111, and the liquid storage tank 111 is placed on one of the adjustable-height placement platforms; A liquid level control tank 112, and the liquid level control tank 112 is placed on the other adjustable-height placement platform; A switchable funnel 113, and the switchable funnel 113 is vertically inserted into the pipe orifice of the liquid storage tank 111; Liquid outlet pipe 114, the liquid outlet pipe 114 is fixed at the bottom end of the side of the liquid storage tank 111, one end of the liquid outlet pipe 114 is inserted into the liquid level control tank 112, and a control valve Ⅰ 115 is installed on the liquid outlet pipe 114; Constant pressure pipe 116, one end of the constant pressure pipe 116 is inserted into the liquid storage tank 111, and the other end of the constant pressure pipe 116 is inserted into the liquid level control tank 112; Among them, one end of the delivery pipe 117 is fixed at the bottom end of the side of the liquid level control tank 112, and a control valve Ⅱ 118 is installed on the delivery pipe 117.

[0043] The bottom of the liquid level control tank 112 is equipped with an interface directly connected to the wick 212 burner. (Note: The volume of the liquid sample tank is 250 ml, and the volume of the liquid level control tank 112 is 100 ml. The connection of the tank body and the pipeline from the tank body to the wick 212 interface is made of fluorine-containing hose material considering factors such as convenient observation, connection and not being easily damaged.) For a further optimized solution, the ignition module includes: Combustion base 201, the combustion base 201 is fixed at the center position of the top surface of the partition 233, and the wick tube 211 is fixed on the top surface of the combustion base 201; Fixed sleeve 202, the fixed sleeve 202 is threadedly connected to the combustion base 201, and a through hole is opened at the center position of the top of the fixed sleeve 202; Heat insulation sleeve 203, the heat insulation sleeve 203 is coaxially arranged inside the fixed sleeve 202; Heating wire 204, the heating wire 204 is arranged on the inner wall of the heat insulation sleeve 203; Atomizer 205, the atomizer 205 is installed on the inner top wall of the fixed sleeve 202, and the atomizer 205 is arranged corresponding to the through hole.

[0044] Heat insulation sleeve 203 tube: inner diameter 15 mm, outer diameter 17 mm, can use PVC plastic material with a length of 31 mm. It can be directly inserted into the groove on the base table and fixed. There is a card slot on the combustion base 201, and the heat insulation sleeve 203 is snapped into the card slot.

[0045] Atomizer 205: Adopt an ultrasonic microporous atomization sheet, which releases the electrolyte spray by vibrating and patting the surface of the wick 212 through high-frequency oscillation, and generally has an inner diameter of less than 20 mm.

[0046] Fixed sleeve 202: inner diameter 20 mm, outer diameter 24 mm, height 36 mm, can be threadedly connected to the lower combustion base, and the height can be adjusted by threading, providing a downward pressure on the wick 212 to make the wick 212 closely adhere to the high-frequency oscillation atomizer 205.

[0047] For a further optimized solution, the rectification module includes: Glass bead rectification layer 221, the glass bead rectification layer 221 is laid at the bottom of the gas rectification chamber 241; The honeycomb perforated plate layer I 222 is arranged above the glass bead rectifying layer 221; The honeycomb perforated plate layer II 223 is arranged on the top surface of the partition plate 233.

[0048] For a further optimized solution, the gas distribution system 3 includes: The gas storage tank 301, and several groups of gas storage tanks 301 are provided; The gas mixing tank 302, and several gas storage tanks 301 are all connected to the gas mixing tank 302 through pipelines; The flow meters 303, and the flow meters 303 are respectively arranged on several groups of pipelines; Wherein, one end of the air inlet pipe is connected to the gas mixing tank 302, and an air supply pump is installed on the air inlet pipe.

[0049] For a further optimized solution, the optical measurement and analysis system 4 includes: The camera 401, and the camera 401 is installed in the experimental darkroom through a support frame; The optical fiber probe 402, and the optical fiber probe 402 is installed on the side wall of the darkroom, and the optical fiber probe 402 is connected to a micro spectrometer; The sheet light source emitter 403, and the sheet light source emitter 403 is installed in the darkroom.

[0050] The camera 401 uses a modern digital camera with high sensitivity and high frame rate. A modular darkroom that can be conveniently disassembled can be installed above the combustion base 231. A probe-type micro spectrometer is adopted, and the detection angle is about 120°. The darkroom is composed of a conveniently disassembled frame and a black curtain. The curtain surrounds the left, right, rear and top of the frame. A reserved air outlet for the combustion tube 232 is opened on the top surface, and a black net is covered above the air outlet. For a further optimized solution, the waste liquid recovery module 5 includes: The recovery bottle 501, and the recovery bottle 501 is placed on the base 231, and the recovery bottle 501 is located below the gas rectifying chamber 241; The control valve III 502, and the discharge pipe is installed on the discharge pipe.

[0051] A method for testing the limiting oxygen concentration of a combustible liquid includes the following steps: Step 1, assemble the experimental device, pre-soak the wick 212, and insert the wick 212 into the top end of the wick tube 211 after the wick 212 meets the experimental requirements; Step 2: Inject the experimental liquid into the constant-pressure liquid supply module and turn on the constant-pressure liquid supply module until the liquid fills the delivery pipe 117 and there is no air residue, and check that the upper end of the wick 212 is wet; after placing the wick 212 and checking that the upper end of the wick 212 is wet, place the high-frequency oscillating atomizer 205 above it, insert it into the heat-insulating sleeve 203 cylinder and fix it preliminarily, determine the position of the atomizer 205 directly above the inner wall of the heat-insulating sleeve 203 cylinder. When it is necessary to heat the experimental liquid, the power supply of the heating wire 204 can be turned on. Finally, screw the fixed sleeve 202, which is threadedly connected to the lower seat of the sleeve, rotate and fix it, and apply a downward pressure to the atomizer 205 through the sleeve so that the atomizer 205 is in close contact with the upper part of the wick 212.

[0052] Turn on the atomizer 205 above the wick 212. As the experiment progresses, the liquid level position in the liquid level control bottle will remain stable due to the air pressure. The wick 212 will continuously and stably suck up the liquid, and continuously atomize the liquid droplets to provide fuel upward.

[0053] Step 3: The gas distribution system 3 operates. The gas distribution concentration, gas flow rate and flow rate are controlled through the control system. The mixed gas is input into the gas rectification chamber 241, and uniform gas distribution is achieved through the rectification module, and then enters the combustion tube 232 through the partition plate 233; open the valves of the oxygen and nitrogen cylinders, and use the microcomputer main control electronics to control the flow rate and flow rate of the two into the gas mixing tank 302, so that the oxygen concentration and flow rate entering the combustion tube 232 can be controlled. The adjustable gas flow rate range of this instrument is about 5 cm / s - 20 cm / s. In view of experimental experience and relevant operating specifications, the commonly used gas flow rate is 10 cm / s.

[0054] Step 4: Use an igniter to ignite the atomized liquid droplets to obtain a stable flame, and judge the stability of the flame through the optical measurement and analysis system 4; the stability of the flame can be judged by a dual standard. One is to judge with a camera and the naked eye, and the other is to judge the stability of the flame using the real-time flame spectrum data obtained by the microprobe.

[0055] Step 5: After determining that the flame and flow rate are stable, the test of the limiting oxygen index can be started. A method similar to the dichotomy is used to determine the limiting oxygen index of liquid fuels such as electrolytes. In the first experiment, the oxygen concentration is reduced by 5% vol each time. According to the replacement time of the new mixed gas in the gas supply system, the test duration under given conditions is at least one minute. If the flame continues to burn for more than one minute, it is determined to be in the "continuous combustion" state, and the oxygen needs to be further reduced. Otherwise, if the flame goes out within one minute, it is determined to be in the "extinguished" state. After initially obtaining an approximate range of the oxygen index, in the second experiment, the oxygen concentration can be directly reduced from a high concentration at the beginning to near the upper limit of the oxygen concentration obtained in the first experiment, and the oxygen concentration is reduced by 1% vol each time to obtain a more accurate oxygen concentration range. And so on, in the third and subsequent experiments, the oxygen concentration is reduced by 0.1% vol each time to obtain the limiting oxygen index of liquid atomization combustion. Repeat the experiment multiple times and take the average value to obtain the range of the limiting oxygen index value.

[0056] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0057] The embodiments described above are only for describing the preferred mode of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A device for testing the limiting oxygen concentration of flammable liquids, characterized in that: include: An electrolyte supply system (1), the electrolyte supply system (1) comprising an adjustable height placement platform and a constant pressure liquid supply module; A combustion system (2), the combustion system (2) comprising a base (231) and a combustion tube (232), the bottom of the combustion tube (232) being fixedly connected to a partition (233), the partition (233) being provided with a plurality of through holes, an ignition module being detachably connected to the center of the top surface of the partition (233), a wick tube (211) being provided in the ignition module, a wick (212) being provided at the top of the wick tube (211), and the constant pressure liquid supply module being connected to the wick tube (211); and an experimental darkroom being installed on the top surface of the base (231); A gas rectification chamber (241), the gas rectification chamber (241) being mounted on the base (231), and a rectification module being arranged in the gas rectification chamber (241); A gas distribution system (3), wherein an air intake pipe is installed at the bottom of the gas rectification chamber (241), and an output end of the gas distribution system (3) is connected to one end of the air intake pipe; A control system, the gas distribution system (3) being connected to the control system; An optical measurement and analysis system (4), the optical measurement and analysis system (4) being installed in the experimental darkroom, and the optical measurement and analysis system (4) being connected to a terminal system; Wherein, a waste liquid recovery module (5) is installed at the bottom of the base (231).

2. A flammable liquid limiting oxygen concentration test device according to claim 1, characterized in that: The height-adjustable placement platform comprises: A stand (101), wherein the stand (101) is provided in two groups, and the two groups of the stand (101) are arranged in parallel; Slide tables (102), the vertical frames (101) are respectively connected to the slide tables (102) in a vertical sliding manner; A positioning assembly, the positioning assembly comprising a positioning bolt (103), a positioning hole being provided on a side of the slide (102), the positioning bolt (103) being threadedly connected in the positioning hole, and the positioning bolt (103) being in abutment with the stand (101); Wherein, the stand (101) is provided with scale lines.

3. A flammable liquid limiting oxygen concentration test device according to claim 2, characterized in that: The constant pressure liquid supply module comprises: A liquid storage tank (111), the liquid storage tank (111) being placed on one of the height-adjustable placement platforms; A liquid level control tank (112), the liquid level control tank (112) being placed on another of the height-adjustable placement platforms; A switchable funnel (113), the switchable funnel (113) being vertically plugged into the nozzle of the liquid storage tank (111); a liquid outlet pipe (114), the liquid outlet pipe (114) being fixed to the bottom end of the side of the liquid storage tank (111), one end of the liquid outlet pipe (114) being inserted into the liquid level control tank (112), and a control valve I (115) being installed on the liquid outlet pipe (114); A constant pressure tube (116), one end of the constant pressure tube (116) being inserted into the liquid storage tank (111), and the other end of the constant pressure tube (116) being inserted into the liquid level control tank (112); The liquid level control tank (112) and the wick tube (211) are connected via a delivery pipe (117), one end of the delivery pipe (117) is fixed to the bottom end of the side of the liquid level control tank (112), and a control valve II (118) is installed on the delivery pipe (117).

4. A flammable liquid limiting oxygen concentration test device according to claim 1, characterized in that: The ignition module comprises: A combustion base (201), the combustion base (201) being fixed at the center position of the top surface of the partition (233), and the wick tube (211) being fixed on the top surface of the combustion base (201); A fixed sleeve (202), the fixed sleeve (202) being threadedly connected to the combustion base (201), and a through hole is provided at the center of the top of the fixed sleeve (202); A heat insulation sleeve (203), the heat insulation sleeve (203) being coaxially arranged in the fixed sleeve (202); A heating wire (204), the heating wire (204) being arranged on the inner wall of the heat insulation sleeve (203); An atomizer (205), the atomizer (205) being mounted on the inner top wall of the fixed sleeve (202), the atomizer (205) being arranged corresponding to the through hole.

5. A flammable liquid limiting oxygen concentration test device according to claim 1, characterized in that: The rectifier module comprises: A glass bead rectifying layer (221), wherein the glass bead rectifying layer (221) is laid on the bottom of the gas rectifying chamber (241); A honeycomb hole plate layer I (222), wherein the honeycomb hole plate layer I (222) is arranged above the glass bead rectifying layer (221); A honeycomb hole plate layer II (223), wherein the honeycomb hole plate layer II (223) is arranged on the top surface of the partition plate (233).

6. A flammable liquid limiting oxygen concentration test device according to claim 1, characterized in that: The gas distribution system (3) comprises: Gas storage tanks (301), wherein the gas storage tanks (301) are provided in a plurality of groups; A gas mixing tank (302), wherein the plurality of gas storage tanks (301) are connected to the gas mixing tank (302) via a pipeline; A flow meter (303), wherein the flow meters (303) are respectively arranged on a plurality of groups of the pipelines; One end of the air intake pipe is connected to the air mixing tank (302), and an air supply pump is installed on the air intake pipe.

7. A flammable liquid limiting oxygen concentration test device according to claim 1, characterized in that: The optical measurement and analysis system (4) comprises: A camera (401), the camera (401) being installed in the experimental darkroom via a support frame; An optical fiber probe (402), the optical fiber probe (402) being mounted on a side wall of the darkroom, and the optical fiber probe (402) being connected to a miniature spectrometer; A sheet light source emitter (403), wherein the sheet light source emitter (403) is installed in the dark room.

8. The device for testing the limiting oxygen concentration of flammable liquid according to claim 1, characterized in that: The waste liquid recovery module (5) comprises: A recovery bottle (501), the recovery bottle (501) being placed on the base (231), and the recovery bottle (501) being located below the gas rectification chamber (241); A discharge pipe is installed at the bottom of the gas rectifying chamber (241), and the discharge pipe is arranged corresponding to the recovery bottle (501). A control valve III (502), wherein the control valve III (502) is installed on the discharge pipe.

9. A method for testing the limiting oxygen concentration of a flammable liquid, based on the flammable liquid limiting oxygen concentration testing device according to any one of claims 1 to 8, characterized in that: The steps include: Step 1, assembling the experimental device, pre-soaking the wick (212), and inserting the wick (212) into the top of the wick tube (211) when the wick (212) meets the experimental requirements; Step 2, injecting the experimental liquid into the constant pressure liquid supply module, opening the constant pressure liquid supply module until the liquid fills the delivery tube (117) and no air remains, and checking that the upper end of the wick (212) is wet; Step three, the gas distribution system (3) works, and the gas distribution concentration, gas flow rate and flow rate are controlled by the control system. The mixed gas is input into the gas rectification chamber (241), and the gas is evenly distributed through the rectification module, and then enters the combustion tube (232) through the partition (233); Step 4, using an igniter to ignite the atomized droplets to obtain a stable flame, and using an optical measurement and analysis system (4) to determine the stability of the flame; Step 5. After judging that the flame and flow rate are stable, the limiting oxygen index test can be started. A similar dichotomy method is used to determine the limiting oxygen index of liquid fuels such as electrolytes. In the first experiment, the volume is reduced by 5% vol each time. According to the replacement time of the new mixed gas in the gas supply system, the test duration under given conditions is at least one minute. If the flame continues to burn for more than one minute, it is determined to be in a "continuous combustion" state and oxygen needs to be further reduced. Otherwise, if the flame is extinguished within one minute, it is determined to be in an "extinguished" state. After initially obtaining the approximate range of the oxygen index, the second experiment can be directly reduced from the initial high concentration to the upper limit of the oxygen concentration obtained in the first experiment, and the oxygen concentration can be reduced by 1% vol each time to obtain a more accurate oxygen concentration range. Similarly, in the third and subsequent experiments, the limiting oxygen index of liquid atomization combustion is obtained by reducing the volume by 0.1% vol each time. Repeat the experiment many times and take the average value to obtain the limiting oxygen index value range.

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