In-situ analysis system and method for flash pyrolysis product of energetic material

Abstract

The invention discloses an in-situ analysis system and method for flash pyrolysis products of an energetic material, and the system comprises a flash heating reaction assembly, a dielectric barrier discharge ion source and a mass detector. During analysis, flash pyrolysis products of the energetic material sample quickly enter an ionization area of the dielectric barrier discharge ion source to be ionized under the driving of pressure difference, and mass-to-charge ratio information is output by the mass detector. According to the method, the flash pyrolysis key intermediate product of the energetic material can be obtained, and the method has the advantages of high mass resolution, high response speed and small sample amount.

Description

TECHNICAL FIELD

[0001] The application can obtain key intermediates of flash pyrolysis of energetic materials, and belongs to the technical field of energetic materials; in particular to a system and method for in-situ analysis of flash pyrolysis products of energetic materials TECHNICAL BACKGROUND

[0002] Energetic materials are a kind of special energy materials, which can release a large amount of heat and gas products under the stimulation of external force, heat and the like, and have broad application requirements in military and civil fields.

[0003] The combustion process of energetic materials involves rapid pyrolysis of condensed phase in a flash heating environment (heating speed of 10 3 ~ 10 4 K / s) and redox reaction of pyrolysis products, accompanied by rapid release of energy and rapid evolution of a large amount of intermediates. The pyrolysis intermediates in the flash heating environment are important nodes of the chemical reaction network of the condensed phase of energetic materials, are the key to understanding the reaction mechanism of the condensed phase of energetic materials, and are the basis for building the combustion reaction kinetics model of energetic materials.

[0004] The traditional in-situ analysis technology of pyrolysis products (TG-MS) has a long transmission distance, and the transmission process is unstable. The intermediates are rapidly evolved into stable final products, and a high-energy EI ion source (70 eV) is used, so that a large number of molecular fragments are easily produced in the ionization process. For the study of pyrolysis products of single-element energetic materials, only the information of final products with mass-to-charge ratio less than 70 can be obtained, and the key intermediates are missing. In addition, the TG-MS experimental technology is a slow heating process, and the fastest heating speed is dozens of degrees Celsius per minute, which is not suitable for the study of the pyrolysis mechanism of energetic materials under flash heating conditions. SUMMARY

[0005] In view of the defects or deficiencies of the prior art, the application provides an in-situ analysis system for flash pyrolysis products of energetic materials.

[0006] To this end, the system provided by the application comprises a flash heating reaction assembly, a dielectric barrier discharge ion source and a mass detector.

[0007] The flash heating reaction assembly comprises a pulse power supply and an ignition wire, and the ignition wire is a nichrome wire, a tungsten wire or a platinum wire.

[0008] The plasma release port of the dielectric barrier discharge ion source is coaxial with and oppositely arranged to the sample inlet of the mass detector; and the ignition wire is arranged directly below the plasma region released by the dielectric barrier discharge ion source.

[0009] Optionally, the pulse power voltage is 2-20 V, and the output pulse width is 3-20 ms; the ignition wire has a diameter of 50-200 μm and a length of 1-10 cm.

[0010] Optionally, the distance between the plasma release port of the dielectric barrier discharge ion source and the sample inlet of the mass detector is less than or equal to 40 mm.

[0011] Optionally, the ignition wire is located 5-10 mm below the plasma region released by the dielectric barrier discharge ion source.

[0012] Optionally, the carrier gas of the dielectric barrier discharge ion source is high-purity helium or high-purity argon, and the flow rate is 1-5 mL·min -1 ; the ion source temperature is 50-250℃.

[0013] Optionally, the mass detector uses a time-of-flight mass spectrometer or a triple quadrupole mass spectrometer.

[0014] The application also provides an in-situ analysis method for flash pyrolysis products of energetic materials, which uses the above system to perform in-situ analysis on flash pyrolysis products of energetic materials, and comprises the following steps:

[0015] (1) loading the energetic material onto the surface of the ignition wire;

[0016] (2) setting the parameters of the dielectric barrier discharge ion source and the mass detector and making them work;

[0017] (3) setting the parameters of the pulse ignition power source and starting ignition, and the output pulse width is 3-20 ms; the ignition wire is heated at a speed of 10 3 -10 4 K / s under the action of the pulse current, the energetic material is subjected to flash pyrolysis, and at the same time, the plasma ionized pyrolysis products ejected by the dielectric barrier discharge ion source enter the mass detector for molecular weight detection.

[0018] Optionally, the energetic material is a single-element energetic material or a composite energetic material.

[0019] Additionally, step (1) comprises: adding the dispersion liquid of the energetic material to the surface of the ignition wire, and loading the energetic material onto the surface of the ignition wire after natural volatilization at room temperature for 5-15 min; the dispersion liquid of the energetic material is a suspension liquid formed by dispersing the energetic material in ethanol, methanol or deionized water.

[0020] The present application aims to solve the technical problems of slow heating speed and missing key intermediate products in the prior art such as TG-MS, and meet the needs of research on condensed phase reaction mechanism and combustion reaction kinetics model of energetic materials. In the present application, the pyrolysis products are ionized in situ and analyzed in real time, the sample is installed near the inlet of the mass detector, the transmission distance of the detected substance is shortened to the maximum, the commercial dielectric barrier discharge ion source is used to realize efficient ionization of the intermediate products and final state products, and the ionization energy is low, so that secondary cracking of molecules in the ionization process is not easy to occur.

[0021] The present application can obtain the decomposition products and intermediate state products of the energetic material sample under the condition of flash heating, meet the needs of research on condensed phase reaction mechanism and combustion reaction kinetics model of energetic materials, and has the advantages of high mass resolution, fast response speed and small sample amount. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The structure schematic diagram of the analysis system used in Example 1 of the present application is shown in the figure.

[0023] Figure 2 The platinum wire temperature-time curve measured in Example 1 of the present application is shown in the figure.

[0024] Figure 3 The TIC graph of HMX flash pyrolysis products measured in Example 1 of the present application is shown in the figure.

[0025] Figure 4 The mass spectrum corresponding to the retention time 0.58 min of the TIC graph of HMX flash pyrolysis products measured in Example 1 of the present application is shown in the figure. DETAILED DESCRIPTION

[0026] Unless otherwise specified, the scientific and technical terms in the present application are understood according to the understanding of the ordinary skilled in the art.

[0027] It should be noted that in the present application, the heating rate of the ignition wire can be 10 3 ~ 10 4 K / s by adjusting the pulse power voltage and pulse width, and in the specific scheme, the resistance value of the ignition wire can be monitored in real time, the real-time temperature of the ignition wire can be calculated by using the Callendar-Van Dusen equation, so as to determine the heating rate of the ignition wire.

[0028] In accordance with the above technical scheme, the specific embodiments of the present application are given below, and it should be noted that the present application is not limited to the following specific embodiments.

[0029] Example 1

[0030] The structure schematic diagram of the analysis system used in this embodiment is shown in the figure. Figure 1As shown, it is composed of a flash heating reaction component (a pulse power supply 3 and a 100μm platinum wire 4 are connected by a wire, and the length of the platinum wire is 3cm), a dielectric barrier discharge ion source 1 (Ningbo Huayi Ningchuang DBDI-100) and a mass detector 2 (Hangzhou Puyu Technology EXPEC5200), wherein the plasma jet port of the dielectric barrier discharge ion source and the sample inlet of the mass detector are kept coaxial with a distance of 30mm, and the sample to be pyrolyzed is fixed 5mm below the plasma release area 5 released by the dielectric barrier discharge ion source.

[0031] (1) Sample preparation

[0032] Add 10 mg of HMX to 5 mL of ethanol and disperse it ultrasonically for 5 minutes. Add 1 drop of ethanol dispersion to the surface of the ignition wire and evaporate it naturally at room temperature for 5 minutes. Install the ignition wire as shown in the following figure. Figure 1 Position shown;

[0033] (2) Ion source and mass detector parameter settings

[0034] Set the parameters of the dielectric barrier discharge ion source, use high-purity helium as the carrier gas, and the flow rate is 2 mL min -1 , the ion source temperature is 200℃, making the dielectric barrier discharge ion source in working state;

[0035] Create a new mass spectrometry analysis method, set the detection ion mode to negative ion mode, the scan mode to full scan mode, the scan mass range to 100-400, and put the mass detector into working state;

[0036] (3) Set the ignition power parameters and start the ignition

[0037] Adjust the voltage of the ignition power supply to 10V and the current pulse width to 10ms, and start the ignition. By measuring the resistance value of the platinum wire in real time, the real-time temperature of the platinum wire can be calculated based on the Callendar-Van Dusen equation, such as Figure 2 As shown in the figure, the temperature of the platinum wire is 960℃ at 10ms, and the heating rate during the ignition process is 9.35×10 4 ℃ / s;

[0038] (4) Mass spectrometry data recording and analysis

[0039] The TIC diagram obtained by mass spectrometry is shown in Figure 3, where a strong response signal appears at 0.58 min. The corresponding mass spectrum is shown in Figure 3. Figure 4 As shown, the main ion peaks are 357.94, 331.07, 311.09, 283.63, and 116.19.

Claims

1. An in-situ analysis system for flash pyrolysis products of energetic materials, characterized in that: The system comprises a flash temperature reaction component, a dielectric barrier discharge ion source (1) and a mass detector (2); The flash temperature reaction component comprises a pulse power supply (3) and an ignition wire (4), wherein the ignition wire is a nickel-chromium alloy wire, a tungsten wire or a platinum wire; The plasma release port of the dielectric barrier discharge ion source is coaxial with and opposite to the sample inlet of the mass detector; the ignition wire is arranged directly below the plasma region (5) released by the dielectric barrier discharge ion source.

2. The analysis system according to claim 1, characterized in that The pulse power supply voltage is 2-20V, and the output pulse width is 3-20ms; the ignition wire diameter is 50-200μm, and the length is 1-10cm.

3. The analysis system according to claim 1, characterized in that The distance between the plasma release port of the dielectric barrier ion source and the sample inlet of the mass detector is less than or equal to 40 mm.

4. The analysis system according to claim 1, wherein The ignition wire is located 5 to 10 mm below the plasma area released by the dielectric barrier discharge ion source.

5. The analysis system according to claim 1, wherein The carrier gas of the dielectric barrier discharge ion source is high-purity helium or high-purity argon, with a flow rate of 1 to 5 mL min -1 , the ion source temperature is 50~250℃.

6. The analysis system according to claim 1, characterized in that The mass detector is a time-of-flight mass spectrometer or a triple quadrupole mass spectrometer.

7. A method for in-situ analysis of flash pyrolysis products of energetic materials, characterized in that: The system according to any one of claims 1 to 6 is used to perform in-situ analysis of flash pyrolysis products of energetic materials, the method comprising the following steps: (1) Loading energetic material onto the surface of the ignition wire; (2) Setting the parameters of the dielectric barrier discharge ion source and mass detector and putting them in working state; (3) Set the pulse ignition power supply parameters and start ignition. The output pulse width is 3 to 20 ms. The ignition wire is 10 3 ~10 4 The temperature is increased at a rate of 0.1 K / s, and the energetic material undergoes flash pyrolysis. At the same time, the plasma ejected from the dielectric barrier discharge ion source ionizes the pyrolysis products, which then enter the mass detector for molecular weight detection.

8. The analysis method according to claim 7, characterized in that The energetic material is a simple energetic material or a composite energetic material.

9. The analysis method according to claim 7, characterized in that The step (1) comprises: dropping a dispersion of an energetic material onto the surface of the ignition wire, and loading the energetic material onto the surface of the ignition wire after natural volatilization for 5 to 15 minutes at room temperature; the energetic material dispersion is a suspension formed by dispersing the energetic material in ethanol, methanol or deionized water.

Images