Thermal decomposition parameter test reactor and method under simulated working condition of explosive and powder samples

Abstract

The invention provides a reactor and a method for testing thermal decomposition parameters of explosive and powder samples under simulated working conditions. The reactor comprises a reaction bottle, a sample bottle is arranged in the reaction bottle, an inner cavity of the sample bottle is a sample pool, and the sample pool is used for containing a to-be-tested sample; a tail clamp is arranged at the bottom end of the reaction bottle, a reactor thin tube is arranged in the reaction bottle, an upper pressing column and a lower pressing column are arranged in the reactor thin tube, and a spring is arranged between the upper pressing column and the lower pressing column; and a pressure pipe of the calorimeter is sleeved outside the upper pressing column. By adopting the pressure loading design, certain pressure can be loaded on materials in the explosive and powder technological process, so that the materials are subjected to a thermal acceleration calorimetry test under the pressure, and thermal decomposition parameters of the materials under pressure and temperature coupling loading are obtained. Compared with a heat acceleration calorimetry test only carrying out temperature loading in the prior art, the pressure stress is increased, the method is closer to the actual material state in multiple process stages, and the obtained thermal decomposition parameters can be used for accurately evaluating the safety of the materials in the actual technological process.

Description

Technical Field

[0001] This invention belongs to the field of testing technology for safety parameters of explosives, and relates to the testing of thermal decomposition parameters of materials under static or quasi-static pressure in actual explosive processes. Specifically, it relates to a reactor and method for testing thermal decomposition parameters of explosive samples under simulated working conditions. Background Art

[0002] In recent years, the adoption of new materials, processes, and technologies, coupled with a lack of thorough understanding of existing production line technologies by explosives and pyrotechnics manufacturers and their weak safety design and safety assessment capabilities, has led to a continuous stream of safety accidents and immense pressure on production safety. The recent occurrence of major accidents has particularly compelled the domestic explosives and pyrotechnics industry to thoroughly understand and digest these technologies and to develop and enhance its safety design and assessment capabilities. The most significant difference between materials in process lines and raw materials and finished products is that, in addition to being affected by the natural environment's temperature, humidity, pressure, and atmosphere, they are also subject to process stresses. Different processes, equipment, and process parameters result in varying types and levels of stress on materials. In most manufacturing processes, materials are subjected to pressure or quasi-static pressure, resulting in multiple coupled effects, including pressure and heat, in actual processes. Traditionally, standard accelerated thermal calorimetry tests have only conducted thermal tests under a single temperature factor, yielding only the thermal decomposition parameters of the material at that temperature. However, the decomposition of explosives and pyrotechnics is influenced by multiple factors, including natural environmental factors such as temperature, humidity, and atmosphere, as well as the mechanical environment during the actual process. Essentially, pressure loading will restrict the diffusion of volatile atmospheres and limit heat dissipation. For autocatalytic, self-accelerating energetic materials, the volatile atmosphere may also cause the material to accelerate prematurely. The dual effects of restricted heat dissipation and accelerated decomposition will not only advance the decomposition temperature but also increase the test heat release. Furthermore, it may even manifest as a change in the reaction mechanism. Therefore, to estimate the safety of materials in actual process flows, it is necessary to simulate the environmental stresses to which the materials are subjected during safety parameter testing. Clearly, conventional accelerated thermal calorimetry tests only load temperature factors, excluding other natural and mechanical environmental factors. If the results obtained are used for process safety evaluation, they will clearly increase safety risks and reduce the reliability and accuracy of process safety evaluations. Summary of the Invention

[0003] In view of the defects and shortcomings of the prior art, the object of the present invention is to provide a reactor and method for testing the thermal decomposition parameters of explosive samples under simulated working conditions, thereby resolving the technical problem that the thermal decomposition parameters of actual materials in the explosive manufacturing process cannot be accurately and reliably obtained due to the processing method of the prior art that only the temperature environmental factor is loaded in the thermal acceleration calorimetry test, which in turn makes it difficult to accurately evaluate the safety of the materials in the actual process.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A reactor for testing thermal decomposition parameters of explosive samples under simulated working conditions includes a reaction flask; a sample bottle is disposed at the bottom of the reaction flask, the inner cavity of which is a sample cell for holding the sample to be tested; a tail clamp is disposed at the bottom end of the reaction flask for connecting a thermocouple of a calorimeter, the thermocouple being used to measure the thermal decomposition parameters of the sample to be tested; a reactor tube is disposed inside the reaction flask, with both ends of the reactor tube open axially, and a reaction flask through-hole is disposed at the top end of the reaction flask, through which the top end of the reactor tube extends beyond the top end of the reaction flask, and the bottom end of the reactor tube extends... The sample is placed inside the sample vial; the sealed space enclosed by the inner wall of the reaction flask and the outer wall of the reactor capillary is the reaction chamber; an upper pressure column is installed inside the top of the reactor capillary, and a lower pressure column is installed inside the bottom of the reactor capillary; a spring is installed inside the reactor capillary between the upper and lower pressure columns; the bottom end of the spring is connected to the top end of the lower pressure column, the bottom end of the lower pressure column is in contact with the sample to be tested, the top end of the spring is connected to the bottom end of the upper pressure column, and the top end of the upper pressure column extends outside the top end of the reactor capillary; a pressure tube of a calorimeter is sleeved on the top of the upper pressure column, and the bottom end of the pressure tube is in close contact with the top end of the reactor capillary.

[0006] The present invention also has the following technical features:

[0007] A fixing nut is provided on the top of the reactor tube, and a ferrule is provided between the fixing nut and the reactor tube; a pressure cap is fixedly provided on the outside of the pressure tube, the pressure cap is located above the ferrule, and the bottom of the pressure cap is fixedly installed in the fixing nut.

[0008] The reaction flask is made of titanium alloy.

[0009] The sample vials are made of titanium alloy.

[0010] The material of the spring is selected from chromium silicon alloy, chromium vanadium alloy and nickel copper alloy.

[0011] The lower and upper pressure columns are made of copper.

[0012] The reaction bottle is a hollow spherical structure, and the bottom surface of the sample bottle is a partial spherical surface and matches the inner bottom surface of the reaction bottle.

[0013] The reaction bottle is a hollow cylindrical structure, and the bottom surface of the sample bottle is flat and matches the inner bottom surface of the reaction bottle.

[0014] The length of the downward pressure column in the reactor tube is 3 to 5 mm.

[0015] This invention also protects a method for testing the thermal decomposition parameters of a sample under simulated operating conditions in a pyrotechnic process. This method uses the pyrotechnic sample simulated operating conditions thermal decomposition parameter testing reactor described above. The method specifically includes the following steps:

[0016] Step 1: Based on the actual working conditions and the pressure exerted on the sample to be tested, select the dimensions of the reaction flask, upper pressure column, lower pressure column, and spring, as well as the spring coefficient.

[0017] Step 2: weigh the sample to be tested and use a pressure column to pre-press and initially compact the sample to be tested.

[0018] Step 3: Assemble the lower pressure column with the sample vial containing the sample to be tested, and place it vertically inside the reaction flask. Then, place the spring and upper pressure column into the reaction flask in sequence.

[0019] Step 4: Tighten the fixing nut with a wrench to secure the reaction flask to the pressure tube of the calorimeter.

[0020] Step 5: Attach the thermocouple of the calorimeter to the tail clip of the reaction bottle.

[0021] Step six: Conduct experiments to obtain the thermal decomposition parameters of the sample to be tested during the process.

[0022] The beneficial technical effects of the present invention compared with the prior art are as follows:

[0023] (I) The pressure-loading design employed in this invention applies a certain pressure to materials in the explosives process, allowing them to undergo thermal acceleration calorimetry under pressure and obtain thermal decomposition parameters under coupled pressure and temperature loading. Compared to prior art thermal acceleration calorimetry tests that only perform temperature loading, the addition of pressure stress more closely matches the actual material state at many process stages. The resulting thermal decomposition parameters can be used to accurately assess the safety of materials in the actual process.

[0024] (II) This invention uses spring loading pressure. Based on the actual pressure of the material and the size of the reactor, the spring compression length and deformation pressure are comprehensively designed from the perspectives of spring coefficient, spring length, upper pressure column and lower pressure column size, so as to achieve different pressure loading of the sample. The method is simple, the pressure adjustable range is large, and it is easier to implement with the instrument.

[0025] (III) The thermal decomposition parameter test method of the present invention under simulated working conditions of explosive samples can accurately obtain the thermal decomposition parameters of materials under the coupled action of quasi-static pressure and temperature. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the reactor for the thermal decomposition parameter test of explosive samples under simulated working conditions.

[0027] The symbols in the diagram represent the following: 1-reaction bottle, 2-sample bottle, 3-sample to be tested, 4-tail clip, 5-reactor tube, 6-reaction cell, 7-upper pressure column, 8-lower pressure column, 9-spring, 10-pressure tube, 11-fixing nut, 12-clamp, 13-cap.

[0028] The technical solution of the present invention is further described below in conjunction with embodiments. Detailed Implementation

[0029] In the present invention, thermal decomposition parameters refer to parameters that describe the rate and mechanism of thermal decomposition reaction of a substance under high temperature conditions, mainly including reaction rate constant, activation energy and reaction order.

[0030] It should be noted that, unless otherwise specified, all measuring instruments and components used in this invention are those known in the art. For example, the calorimeter used is a conventional calorimeter known in the prior art.

[0031] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0032] Example 1:

[0033] This embodiment provides a thermal decomposition parameter test reactor for explosive samples under simulated working conditions. Figure 1 As shown, it includes a reaction bottle 1; a sample bottle 2 is arranged at the bottom of the reaction bottle 1, the inner cavity of the sample bottle 2 is a sample pool, and the sample pool is used to hold a sample 3 to be tested; a tail clip 4 is arranged at the bottom of the reaction bottle 1, and the tail clip 4 is used to connect the temperature measuring thermocouple of the calorimeter, and the temperature measuring thermocouple is used to measure the thermal decomposition parameters of the sample 3 to be tested; a reactor capillary 5 is arranged in the reaction bottle 1, and both axial ends of the reactor capillary 5 are open, a reaction bottle through hole is opened on the top of the reaction bottle 1, the top of the reactor capillary 5 extends out of the top of the reaction bottle 1 through the reaction bottle through hole, and the bottom end of the reactor capillary 5 extends into the sample bottle 2; the inner wall of the reaction bottle 1 The enclosed space surrounded by the outer wall of the reactor capillary 5 is the reaction pool 6; an upper pressure column 7 is provided in the top of the reactor capillary 5, a lower pressure column 8 is provided in the bottom of the reactor capillary 5, and a spring 9 is provided in the reactor capillary 5 between the upper pressure column 7 and the lower pressure column 8; the bottom end of the spring 9 is connected to the top of the lower pressure column 8, the bottom end of the lower pressure column 8 is in contact with the sample to be tested 3, the top end of the spring 9 is connected to the bottom end of the upper pressure column 7, and the top end of the upper pressure column 7 extends out of the top end of the reactor capillary 5; the top of the upper pressure column 7 is outer-coated with a pressure tube 10 of a calorimeter, and the bottom end of the pressure tube 10 is in close contact with the top of the reactor capillary 5.

[0034] In this embodiment, the reaction flask 1, the reactor capillary tube 5, and the tail clamp 4 are connected by welding. During the experiment, the thermocouple of the calorimeter is clamped at the tail clamp 4 to measure the temperature at the bottom of the reaction flask 1.

[0035] In this embodiment, the spring 9 is always inside the reactor tube 5 during the compression process, ensuring that the sample is subjected to vertical force when the spring 9 is compressed.

[0036] In this embodiment, the pressure applied to the test sample 3 can be adjusted by adjusting the spring coefficient of the spring 9 and the length of the upper pressure column 7 to simulate the loading of the test sample 3 under different pressures. When the size of the upper pressure column 7 is fixed, the compression displacement of the spring 9 is the same each time it is compressed.

[0037] In this embodiment, after the bottom end of the pressure tube 10 is in close contact with the top end of the reactor thin tube 5, the bottom surface of the pressure tube 10 of the calorimeter becomes the limiting surface of the upper pressure column 7. During assembly, the upper pressure column 7 compresses the spring 9 to generate pressure, which is transmitted to the sample 3 to be tested in the sample bottle 2 through the lower pressure column 8, so that the sample is subjected to static pressure.

[0038] In this embodiment, the shape and size of the reaction flask 1 can be changed as needed within the allowable range of the heating chamber of the calorimeter. It can be a spherical reactor or a cylindrical reactor, and its specific structure can be customized according to the calorimeter. For example, an adiabatic accelerating calorimeter can use either a cylindrical or a spherical reaction cell, while a heat flux micro calorimeter can use a cylindrical reaction cell. The size of the reactor determines the length of the lower pressure column 8 and the upper pressure column 7 of the spring 9, determines the displacement of the spring 9 during assembly, and thus determines the range of applied pressure.

[0039] As a specific embodiment, a fixing nut 11 is provided on the top of the reactor tube 5, and a sleeve 12 is provided between the fixing nut 11 and the reactor tube 5; a pressure cap 13 is fixedly provided on the outside of the pressure tube 10, the pressure cap 13 is located above the sleeve 12, and the bottom of the pressure cap 13 is fixedly installed in the fixing nut 11.

[0040] In this embodiment, the reaction bottle 1 is connected to the pressure tube 10 of the calorimeter by the fixing nut 11 and sealed by the ferrule 6. The upper end of the upper pressure column 7 is in contact with the pressure tube 10. There is a compression spring 9 between the upper pressure column 7 and the lower pressure column 8. When assembled, the spring 9 is compressed, and the pressure generated is transmitted to the sample 3 to be tested in the sample bottle 2 through the lower pressure column 8.

[0041] As a specific embodiment, the reaction flask 1 is made of titanium alloy, which reduces the wall thickness under the same pressure, improves thermal conductivity, and increases the timeliness of temperature measurement.

[0042] As a specific embodiment, sample bottle 2 is made of titanium alloy, which improves thermal conductivity and increases the timeliness of sample temperature measurement.

[0043] As a specific solution of this embodiment, the material of the spring 9 is selected from high-temperature resistant materials, such as chromium-silicon alloy, chromium-vanadium alloy and nickel-copper alloy, so that the pressure on the sample in the thermal test mode will not change significantly due to temperature.

[0044] As a specific embodiment, the lower pressure column 8 and the upper pressure column 7 are made of copper to minimize the heat generated by the sample and use it to heat the lower pressure column 8 and the upper pressure column 7.

[0045] As a specific embodiment, the bottom surface of sample bottle 2 is partially spherical (i.e., a spherical cap) to ensure good contact with the inside of reaction bottle 1 and increase the heat conduction area between sample bottle 2 and reaction bottle 1.

[0046] As a specific embodiment, the outer diameters of the upper pressure column 7, spring 9, and lower pressure column 8 are matched with the inner diameter of the reactor tube 5 to ensure that the sample is subjected to vertical force when the spring 9 is compressed.

[0047] As a specific solution of this embodiment, the length of the lower pressure column 8 ensures that after being assembled with the sample bottle 2 and the sample to be tested 3, the length of its upper part in the reactor tube 5 is 3 to 5 mm, ensuring that when the spring 9 is compressed and stressed, the sample is vertically stressed.

[0048] The working principle of this invention is as follows: Sample bottle 2 is connected to the matching lower pressure column 8. A spring 9 is placed between the lower pressure column 8 and the upper pressure column 7. The upper end face of the upper pressure column 7 is in contact with the pressure tube 10 of the calorimeter. During assembly, the pressure generated by the compression deformation of the spring 9 is transmitted to the sample to be tested 3 in the sample cell through the lower pressure column 8. The applied pressure can be adjusted by the length and coefficient of the spring 9, or by the length of the upper pressure column 7. This invention uses the compression of the spring 9 to generate pressure, and applies pressure to the sample through the lower pressure column 8. The lower end of the lower pressure column 8 matches the sample cell, and the upper end of the lower pressure column 8 is located in the reactor capillary tube 5. The outer diameters of the spring 9, the lower pressure column 8, and the upper pressure column 7 match the inner diameter of the reactor capillary tube 5 to ensure that the sample cell, the sample to be tested 3, the lower pressure column 8, the spring 9, and the upper pressure column 7 are on a straight line during assembly and compression, thereby ensuring vertical force application. During the experiment, the spring coefficient of spring 9 and the length of upper pressure column 7 are selected based on the actual process pressure and the contact area between the lower pressure head and the sample, so that the pressure on the test sample 3 is within the actual pressure range, simulating the static or quasi-static pressure experienced by the actual material. After assembly, the calorimeter's standard mode can be used to obtain thermal decomposition parameters such as the decomposition temperature of the material under a certain pressure.

[0049] Example 2:

[0050] This embodiment provides a method for testing the thermal decomposition parameters of a sample to be tested under simulated working conditions during a propellant and explosive process. The method uses the reactor for testing the thermal decomposition parameters of the propellant and explosive sample under simulated working conditions described in Example 1. The method specifically comprises the following steps:

[0051] Step 1: According to the actual working conditions, the dimensions of the reaction bottle 1, the upper pressure column 7, the lower pressure column 8 and the spring 9, as well as the spring 9 coefficient are selected to ensure that the loading pressure reaches the actual pressure variation range when the spring 9 is compressed.

[0052] Step 2: Weigh the sample 3 to be tested and pre-compress it using the pressure column 8 to initially tighten the sample 3 to be tested.

[0053] Step three: Assemble the lower pressure column 8 with the sample bottle 2 containing the sample 3 to be tested, and vertically place it into the reaction bottle 1, and then place the spring 9 and the upper pressure column 7 into the reaction bottle 1 in order.

[0054] Step 4: Tighten the fixing nut 11 with a wrench to fix the reaction flask 1 to the pressure tube 10 of the calorimeter.

[0055] Step 5: Clamp the temperature measuring thermocouple of the calorimeter onto the tail clip 4 of the reaction bottle 1.

[0056] Step 6: Set the test mode according to the standard mode of "heating-waiting-searching" to conduct the test to obtain the thermal decomposition parameters of the test sample 3 under a certain pressure during the process.

Claims

1. A reactor for testing thermal decomposition parameters of explosive samples under simulated working conditions, characterized in that: The invention comprises a reaction bottle (1); a sample bottle (2) is arranged at the bottom of the reaction bottle (1); the inner cavity of the sample bottle (2) is a sample pool, and the sample pool is used to hold a sample to be tested (3); a tail clip (4) is arranged at the bottom of the reaction bottle (1), and the tail clip (4) is used to connect a temperature measuring thermocouple of a calorimeter, and the temperature measuring thermocouple is used to measure the thermal decomposition parameters of the sample to be tested (3); A reactor capillary (5) is arranged in the reaction bottle (1), both axial ends of the reactor capillary (5) are open, a reaction bottle through hole is opened on the top of the reaction bottle (1), the top of the reactor capillary (5) extends out of the top of the reaction bottle (1) through the reaction bottle through hole, and the bottom of the reactor capillary (5) extends into the sample bottle (2); the closed space surrounded by the inner wall of the reaction bottle (1) and the outer wall of the reactor capillary (5) is a reaction pool (6); An upper pressure column (7) is arranged in the top of the reactor capillary (5), a lower pressure column (8) is arranged in the bottom of the reactor capillary (5), and a spring (9) is arranged in the reactor capillary (5) between the upper pressure column (7) and the lower pressure column (8); the bottom end of the spring (9) is connected to the top end of the lower pressure column (8), the bottom end of the lower pressure column (8) is in contact with the sample to be tested (3), the top end of the spring (9) is connected to the bottom end of the upper pressure column (7), and the top end of the upper pressure column (7) extends out of the top end of the reactor capillary (5); the top of the upper pressure column (7) is provided with a pressure tube (10) of a calorimeter, and the bottom end of the pressure tube (10) is in close contact with the top end of the reactor capillary (5).

2. The thermal decomposition parameter test reactor for explosive samples under simulated working conditions as claimed in claim 1, characterized in that: A fixing nut (11) is arranged on the outside of the top of the reactor capillary (5), and a ferrule (12) is arranged between the fixing nut (11) and the reactor capillary (5); a pressure cap (13) is fixedly arranged on the outside of the pressure tube (10), the pressure cap (13) is located above the ferrule (12), and the bottom of the pressure cap (13) is fixedly installed in the fixing nut (11).

3. The thermal decomposition parameter test reactor under the simulated working condition of the explosive sample according to claim 1, characterized in that: The reaction bottle (1) is made of titanium alloy.

4. The thermal decomposition parameter test reactor under the simulated working condition of the explosive sample according to claim 1, characterized in that: The sample bottle (2) is made of titanium alloy.

5. The thermal decomposition parameter test reactor under the simulated working condition of the explosive sample according to claim 1, characterized in that: The material of the spring (9) is selected from chrome-silicon alloy, chrome-vanadium alloy and nickel-copper alloy.

6. The thermal decomposition parameter test reactor for explosive samples under simulated working conditions as claimed in claim 1, characterized in that: The lower pressure column (8) and the upper pressure column (7) are made of copper.

7. The thermal decomposition parameter test reactor for explosive samples under simulated working conditions as claimed in claim 1, characterized in that: The reaction bottle (1) is a hollow spherical structure, and the bottom surface of the sample bottle (2) is a partial spherical surface and matches the inner bottom surface of the reaction bottle (1).

8. The thermal decomposition parameter test reactor for explosive samples under simulated working conditions as claimed in claim 1, characterized in that: The reaction bottle (1) is a hollow cylindrical structure, and the bottom surface of the sample bottle (2) is a plane and matches the inner bottom surface of the reaction bottle (1).

9. The thermal decomposition parameter test reactor for explosive samples under simulated working conditions as claimed in claim 1, characterized in that: The length of the lower pressure column (8) in the reactor capillary (5) is 3 to 5 mm.

10. A method for testing the thermal decomposition parameters of a sample to be tested in a pyrotechnic process under simulated working conditions, characterized in that: The method uses a thermal decomposition parameter test reactor under simulated working conditions of a propellant and explosive sample as claimed in any one of claims 1 to 9; the method specifically comprises the following steps: Step 1, according to the pressure of the sample to be tested (3) under actual working conditions, the sizes of the reaction bottle (1), the upper pressure column (7), the lower pressure column (8) and the spring (9), as well as the coefficient of the spring (9) are selected; Step 2, weighing the sample to be tested (3), and using a lower pressure column (8) to pre-press and initially compact the sample to be tested (3); Step 3, assemble the lower pressure column (8) with the sample bottle (2) containing the sample to be tested (3), and vertically place it into the reaction bottle (1), and place the spring (9) and the upper pressure column (7) into the reaction bottle (1) in order; Step 4: Use a wrench to tighten the fixing nut (11) to fix the reaction bottle (1) on the pressure tube (10) of the calorimeter; Step 5, clamping the temperature measuring thermocouple of the calorimeter on the tail clip (4) of the reaction bottle (1); Step six, conducting an experiment to obtain the thermal decomposition parameters of the sample (3) to be tested during the process.

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