CN113694782B - Micro-nano explosive preparation system and method based on coaxial focusing micro-mixer - Google Patents

Abstract

The application discloses a micro-nano explosive preparation system and method based on a coaxial focusing micro-mixer. The device comprises a steady flow driving unit, a high-pressure fluid driving unit, a recrystallization unit and a collection unit, wherein the recrystallization unit and the collection unit comprise a coaxial focusing micro-mixer; the coaxial focusing micromixer comprises an inner microtube, an outer microtube and a T-shaped three-way joint; the steady flow driving unit is connected with the internal microtube and provides flowing driving force for the solvent, and the high-pressure fluid driving unit is connected with the T-shaped three-way joint and provides flowing driving force for the non-solvent; the coaxial focusing micromixer realizes the mixing of the solvent and the non-solvent through the injection from the internal microtube to the external microtube, and generates explosive suspension; the collecting unit is used for recovering the explosive suspension and collecting finished products. The application completes the efficient mixing of the solution and the antisolvent through the axially parallel inner and outer microtubes, has the advantages of no flow rate limitation, high efficiency, less working procedures, convenience, simple structure, small volume and high product quality, and is easy to realize continuous production.

Description

Micro-nano explosive preparation system and method based on coaxial focusing micro-mixer

technical field

The invention belongs to the field of energetic material preparation, and in particular relates to a micro-nano explosive preparation system and method based on a coaxial focusing micro-mixer.

Background technique

As an energetic material, explosives are widely used in engineering blasting, aerospace, explosive forming, weapon systems, etc., and play a key role in promoting the progress of human society. At present, there are many preparation methods for micro-nano explosives, mainly including sol-gel method, mechanical ball milling method, atomization crystallization method and conventional solvent/non-solvent method, but the existing preparation methods have more or less shortcomings. Among them, the sol-gel method is a method for preparing micro-nano explosives through wet chemistry, but the experimental cycle of this method is long, usually requiring several days or weeks; the mechanical ball milling method is through the impact, extrusion, The method of breaking the particles under the action of mechanical force such as shearing, but the particle size of the micro-nano explosives prepared by this method is not uniform enough, the particle size distribution range is wide, and impurities are easily introduced; the conventional solvent/non-solvent method is time-consuming to prepare and screen micro-nano explosives The obtained micro-nano explosives have a wide particle size distribution, poor crystal morphology controllability, high consumption of solvents and non-solvents, high cost, and the risk of environmental pollution. To sum up, the existing methods have complex operation steps, long development cycle, large consumption of reagents, poor reproducibility and potential danger, etc., making it difficult to realize the rapid preparation and screening of micro-nano explosives.

Microfluidic technology is a technology that uses micro-pipes to precisely control and manipulate micro-scale fluids, especially sub-micron structures. It is a multi-disciplinary discipline that includes engineering, physics, chemistry, microfabrication and bioengineering. In recent decades, with the rapid development of microfluidic technology, people have begun to explore the dynamics and flow behavior of multiphase flow droplets at the microscale, the droplet manipulation technology in microchannels, and the application of this technology. , one of which is widely used in the preparation of micro-nanoparticles. Compared with traditional batch reaction, microfluidic technology has higher mixing efficiency, faster heat and mass transfer rate, lower reagent consumption and more precise control of reaction parameters.

So far, there have been examples of applying microfluidic technology to the preparation of explosives (CN201910793520.5) (CN201811027496.6). Based on microfluidic technology, the rapid preparation and screening of explosives with a narrow particle size distribution has been achieved. At the same time, in To a certain extent, the morphology control of explosives at the micro scale has been realized. However, limited by the working characteristics of the oscillator and the structure of the micro-mixer, it is difficult to adjust the flow rate ratio of the solution and the anti-solvent in a wide range.

Contents of the invention

The object of the present invention is to provide a micro-nano explosive preparation system and method based on a coaxial focusing micro-mixer.

The technical solution to realize the object of the present invention is: a micro-nano explosive preparation system based on a coaxial focusing micro-mixer, including a steady flow driving unit, a high-pressure fluid driving unit, a recrystallization unit including a coaxial focusing micro-mixer, collecting Units and related connecting components;

The coaxial focusing micromixer includes internal microtubes, external microtubes and "T" type tee joints; the "T" type tee joints are connected to the external microtubes, and the internal microtubes are set between the "T" type tee joints and the external the interior of microtubules;

The steady-flow drive unit is connected to the internal microtube and provides the driving force for the solvent, and the high-pressure fluid drive unit is connected to the "T" type tee joint to provide the flow driving force for the non-solvent; The injection of the external micropipe achieves the mixing of solvent and non-solvent to generate explosive suspension; the collection unit is used to recover the explosive suspension and collect the finished product.

Further, it also includes a "Y" joint, the outlet of the high-pressure fluid drive unit is connected to one end of the "Y" joint, and the two outlets of the "Y" joint are respectively connected to two ports of the "T" tee joint.

Further, the recrystallization unit also includes a temperature control device for controlling the recrystallization temperature.

Further, the steady flow driving unit comprises a pump device and a syringe, and the pump device drives the solution in the syringe;

The high-pressure fluid driving unit includes a high-pressure gas cylinder, a pressure regulator and a sealed tank. The gas in the high-pressure gas cylinder generates high pressure to drive the solution in the sealed tank to flow along the connecting pipeline to the coaxial focusing micro-mixer.

Further, the material of the inner microtube and the outer microtube is stainless steel, PTFE or glass, and the inner diameter of the inner microtube and the outer microtube is in the range of 50-5000 μm.

A use of the above-mentioned system for preparing micro-nano explosives.

A method for preparing micro-nano explosives using the above-mentioned system, comprising the steps of:

Step 1: According to the crystallization characteristics of the explosive to be recrystallized, determine the diameters of the inner microtube and the outer microtube of the coaxial focusing micro-mixer;

Step 2: connecting each unit of the preparation system;

Step 3: dissolving the explosive in a solvent, dissolving the surfactant in a solvent or a non-solvent, and preparing a solvent and a non-solvent solution;

Step 4: Put the solvent and non-solvent solution in the drive unit, and set the flow rate of the drive unit for standby;

Step 5: Turn on the temperature control device, and set the recrystallization temperature on the temperature control device;

Step 6: When the temperature is heated to the set temperature, turn on the drive unit, push the solvent and non-solvent solution into the coaxial focusing micro-mixer, the solvent and the non-solvent contact and quickly mix to form an explosive suspension;

Step 7: The explosive suspension flowing out of the coaxial focusing micro-mixer is directly passed into the collection unit to complete the preparation of the micro-nano explosive.

Further, the concentration of the explosive dissolved in the solvent in step 3 ranges from 1 g/L to 10 kg/L, and the concentration of the surfactant dissolved in the solvent or non-solvent ranges from 0.005 g/L to 5 g/L.

Further, the flow rate of the solvent in step 4 ranges from 0.1 to 60 mL/min, the flow rate of the non-solvent ranges from 1 to 500 mL/min, and the flow rate ratio of the non-solvent to the solvent ranges from 0.017 to 5000.

Further, the recrystallization temperature in step five is 0-90°C.

The present invention compares with traditional technology, and its significant advantage is:

1. In the preparation system of the present invention, the inner and outer microtubes parallel in the axial direction complete the efficient mixing of the solution and the anti-solvent, and are not limited by the flow ratio, so it is easy to realize the preparation of multi-particle size explosives.

2. Using this system to prepare explosives has fast speed, high yield, short research and development cycle, less energy and material consumption, and less environmental pollution. It is very suitable for the optimization and screening of experimental parameters in the process of explosive preparation.

3. The system can simply parallel recrystallization units to achieve high-throughput screening and mass production.

Description of drawings

Fig. 1 is a schematic diagram of a micro-nano explosive preparation system based on a coaxial focusing micro-mixer of the present invention.

Fig. 2 is a sample morphology diagram of hexanitrostilbene obtained in Example 1 of the present application.

Explanation of reference signs:

1-Stable flow driving unit, 2-High pressure fluid driving unit, 3-Y-type joint, 4-Recrystallization unit, 5-Collection unit.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Referring to FIG. 1 , a micro-nano explosive preparation system based on a coaxial focusing micro-mixer of the present invention includes a fluid drive unit, a recrystallization unit, a post-processing unit and connecting components. Among them, the fluid driving unit provides flow driving force for solvent and non-solvent; the recrystallization unit includes a coaxial focusing micro-mixer and a temperature control device, and the coaxial focusing micro-mixer realizes rapid mixing through a micro-mixing structure; the temperature control device is used to control explosives The temperature during the preparation process; the solvent and non-solvent solutions flow into the coaxial focusing micro-mixer of the recrystallization unit driven by the fluid drive unit, and the solvent and non-solvent solution are contacted and mixed rapidly in the coaxial focusing micro-mixer to generate explosives The suspension, the explosive suspension flows into the collection unit, and the collection unit is used to recover the explosive suspension and collect finished products.

Wherein the non-solvent is water, petroleum ether or chloroform, the solvent is DMSO, DMF, acetone, ethanol or ethyl acetate, the surfactant is polyvinylpyrrolidone (PVP10), CTAB, polyethylene glycol or OP-10, the solvent The flow rate range of non-solvent is 0.1-60mL/min, the flow rate range of non-solvent is 1-500mL/min, the range of non-solvent and solvent flow rate ratio is 0.017-5000, the recrystallization temperature range is 0-90°C, the explosive is dissolved in the solvent The concentration range is 1g/L-10kg/L, and the concentration range of the surfactant dissolved in the solvent or non-solvent is 0.005g/L-5g/L.

The following examples only further illustrate the present invention, and should not be construed as limiting the present invention.

Example 1

Preparation of Hexanitrostilbene by Coaxial Focusing

Hexanitrostilbene explosives were prepared using a coaxial focusing micro-mixer preparation system. Hexanitrostilbene explosives were prepared with DMSO as solvent and deionized water as non-solvent. Dissolve 3000mg of HNS in 300mL of DMSO solvent, put it in a bottle, driven by a continuous steady flow drive device syringe pump, the flow rate is set at 8mL/min, and the non-solvent solution is driven by a high-pressure fluid drive device, with a flow rate of 160mL/min. The recrystallization temperature was set at 25 °C. Turn on the switch of the drive unit, the solvent solution and the non-solvent solution are respectively driven by the steady flow drive device and the high-pressure fluid drive device, and flow into the coaxial focusing micro-mixer, the solvent and the non-solvent contact and mix rapidly to form a hexanitrostilbene explosive Suspension, introducing the hexanitrostilbene explosive suspension flowing out of the micro-mixer into the collection unit, and finally obtaining hexanitrostilbene explosive particles. The morphology of the obtained HNS is shown in Fig. 2.

Claims (5)

1. The application of a micro-nano explosive preparation system based on a coaxial focusing micro-mixer is characterized in that the system is used for preparing micro-nano explosives;

the system comprises a steady flow driving unit, a high-pressure fluid driving unit, a recrystallization unit comprising a coaxial focusing micro-mixer, a collection unit and related connecting components; the coaxial focusing micromixer comprises an inner microtube, an outer microtube and a T-shaped three-way joint; the T-shaped three-way joint is connected with an external micro-pipe, and the internal micro-pipe is arranged inside the T-shaped three-way joint and the external micro-pipe; the steady flow driving unit is connected with the internal microtube and provides flowing driving force for the solvent, and the high-pressure fluid driving unit is connected with the T-shaped three-way joint and provides flowing driving force for the non-solvent; the coaxial focusing micromixer realizes the mixing of the solvent and the non-solvent through the injection from the internal microtube to the external microtube, and generates explosive suspension; the collecting unit is used for recovering the explosive suspension and collecting finished products; the high-pressure fluid driving unit comprises a high-pressure gas cylinder, a pressure regulator and a sealing tank, wherein gas in the high-pressure gas cylinder generates high pressure to drive a solution in the sealing tank to flow to the coaxial focusing micro-mixer along a connecting pipeline;

the system also comprises a Y-shaped connector, an outlet of the high-pressure fluid driving unit is connected with one end of the Y-shaped connector, and two outlets of the Y-shaped connector are respectively connected with two ports of the T-shaped three-way connector;

the recrystallization unit also comprises a temperature control device for controlling the temperature of recrystallization;

the steady flow driving unit comprises a pump device and a syringe, and the pump device drives the solution in the syringe;

the inner microtubes and the outer microtubes are made of stainless steel, PTFE or glass, and the inner diameters of the inner microtubes and the outer microtubes are 50-5000 μm.

2. Use according to claim 1, characterized in that it comprises in particular the following steps:

step one: determining the pipe diameters of an inner micro pipe and an outer micro pipe of the coaxial focusing micro mixer according to the crystallization characteristics of the to-be-recrystallized explosive;

step two: connecting the units of the preparation system;

step three: dissolving explosive in a solvent, dissolving a surfactant in a solvent or a non-solvent, and preparing a solvent and a non-solvent solution;

step four: placing the solvent and the non-solvent solution in a driving unit, and setting the flow rate of the driving unit for standby;

step five: starting a temperature control device, and setting a recrystallization temperature on the temperature control device;

step six: when the temperature is heated to the set temperature, starting a driving unit to push the solvent and the non-solvent solution to flow into a coaxial focusing micro-mixer, and enabling the solvent to be in contact with the non-solvent and to be quickly mixed to generate explosive suspension;

step seven: and directly introducing the explosive suspension flowing out of the coaxial focusing micro-mixer into a collecting unit to finish the preparation of the micro-nano explosive.

3. The use according to claim 2, wherein the concentration of the explosive in step three dissolved in the solvent is in the range of 1g/L to 10kg/L and the concentration of the surfactant dissolved in the solvent or non-solvent is in the range of 0.005g/L to 5g/L.

4. The use according to claim 3, wherein the solvent in the fourth step has a flow rate in the range of 0.1 to 60ml/min, the non-solvent has a flow rate in the range of 1 to 500ml/min, and the ratio of the non-solvent to the solvent has a flow rate in the range of 0.017 to 5000.

5. The method according to claim 4, wherein the recrystallization temperature in step five is 0-90 ℃.