CN113694782A

CN113694782A - Micro-nano explosive preparation system and method based on coaxial focusing micro mixer

Info

Publication number: CN113694782A
Application number: CN202110985524.0A
Authority: CN
Inventors: 朱朋; 石锦宇; 沈瑞祺; 叶迎华
Original assignee: Nanjing University of Science and Technology
Current assignee: Nanjing University of Science and Technology
Priority date: 2021-08-26
Filing date: 2021-08-26
Publication date: 2021-11-26
Anticipated expiration: 2041-08-26
Also published as: CN113694782B

Abstract

The invention discloses a micro-nano explosive preparation system and method based on a coaxial focusing micro-mixer. Including steady flow drive unit, high pressure fluid drive unit, recrystallization unit and collection unit including coaxial focusing micromixer; coaxial focusing micromixer includes inner microtube, outer microtube and "T" type tee joint; stable The flow driving unit is followed by the internal microtube and provides the flow driving force for the solvent, the high pressure fluid driving unit is followed by a "T" type tee joint and provides the flow driving force for the non-solvent; the coaxial focusing micromixer passes the internal microtube to the outside The spray of the microtube realizes the mixing of the solvent and the non-solvent to generate the explosive suspension; the collecting unit is used to recover the explosive suspension and collect the finished product. The invention completes the efficient mixing of the solution and the anti-solvent through the parallel inner and outer microtubes in the axial direction, and has the advantages of not being restricted by the flow ratio, high efficiency, few processes, 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 particularly relates to a micro-nano explosive preparation system and method based on a coaxial focusing micro mixer.

Background

As an energetic material, the explosive is widely applied to engineering blasting, aerospace, explosive forming, weapon systems and the like, and plays a key role in promoting the progress of human society. At present, various preparation methods of the micro-nano explosive are available, mainly including a sol-gel method, a mechanical ball milling method, an atomization crystallization method and a conventional solvent/non-solvent method, but the existing preparation methods have more or less defects. The sol-gel method is a method for preparing the micro-nano explosive by wet chemistry, but the experimental period of the method is long, and usually several days or weeks are needed; the mechanical ball milling method is a method for crushing particles through mechanical force effects of impact, extrusion, shearing and the like of a ball milling medium, but the micro-nano explosive prepared by the method has the advantages of uneven particle size, wide particle size distribution range and easiness in introducing impurities; the conventional solvent/non-solvent method is time-consuming and labor-consuming in preparing and screening the micro-nano explosive, the obtained micro-nano explosive is wide in particle size distribution, poor in controllability of crystal morphology, large in solvent and non-solvent consumption, high in cost, high in risk of environmental pollution and the like. In conclusion, the existing method has the disadvantages of complex operation steps, long research and development period, large reagent consumption, poor repeatability, potential dangerousness and the like, and the rapid preparation and screening of the micro-nano explosive are difficult to realize.

The microfluidic technology is a technology for precisely controlling and controlling micro-scale fluid by using a micro-pipeline, particularly a technology of a submicron structure, and is a multi-cross discipline comprising engineering, physics, chemistry, micro-processing and biological engineering. In recent decades, with the rapid development of microfluidic technology, people begin to explore the dynamics principle and the flow behavior of multi-phase flow droplets on a microscale, the droplet control technology in microchannels, and the application research of the technology, one of which is widely applied to the preparation of micro-nano particles. Compared with the traditional batch reaction, the micro-fluidic technology has higher mixing efficiency, faster heat and mass transfer rate, lower reagent consumption and more accurate reaction parameter control.

So far, an example of applying the microfluidic technology to explosive preparation has appeared (CN201910793520.5) (CN201811027496.6), and based on the microfluidic technology, the rapid preparation and screening of explosives with narrow particle size distribution has been realized, and at the same time, the shape control of explosives under micro-scale is realized to a certain extent. However, the flow rate ratio of the solution and the anti-solvent is difficult to control in a wide range due to the operational characteristics of the oscillator and the structure of the micro-mixer.

Disclosure of Invention

The invention aims to provide a micro-nano explosive preparation system and a method based on a coaxial focusing micro-mixer.

The technical solution for realizing the purpose of the invention is as follows: a micro-nano explosive preparation system based on a coaxial focusing micro mixer comprises a steady flow driving unit, a high-pressure fluid driving unit, a recrystallization unit comprising the coaxial focusing micro mixer, a collection unit and a related connecting assembly;

the coaxial focusing micro mixer comprises an inner micro pipe, an outer micro pipe and a T-shaped three-way joint; the rear part of the T-shaped three-way joint is connected with an external micro-pipe, and the internal micro-pipe is arranged in the T-shaped three-way joint and the external micro-pipe;

the steady flow driving unit is connected with the inner micro-tube and provides a flow driving force for the solvent, and the high-pressure fluid driving unit is connected with the T-shaped three-way joint and provides a flow driving force for the non-solvent; the coaxial focusing micro-mixer realizes the mixing of a solvent and a non-solvent by the injection of an inner micro-tube to an outer micro-tube to generate an explosive suspension; the collecting unit is used for recovering the explosive suspension and collecting finished products.

Furthermore, the high-pressure fluid driving device further comprises a Y-shaped joint, an outlet of the high-pressure fluid driving unit is connected with one end of the Y-shaped joint, and two outlets of the Y-shaped joint are respectively connected with two ports of the T-shaped three-way joint.

Further, the recrystallization unit further comprises a temperature control device for controlling the temperature of recrystallization.

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

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

Furthermore, the inner micro-tube and the outer micro-tube are made of stainless steel, PTFE or glass, and the inner diameter range of the inner micro-tube and the outer micro-tube is 50-5000 microns.

The application of the system is used for preparing the micro-nano explosive.

A method for preparing the micro-nano explosive by adopting the system comprises the following steps:

the method comprises the following steps: 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 explosive to be recrystallized;

step two: connecting each unit of the preparation system;

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

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

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

step seven: and (3) directly introducing the explosive suspension flowing out of the coaxial focusing micro mixer into a collection unit to finish the preparation of the micro-nano explosive.

Furthermore, the concentration range of the explosive dissolved in the solvent in the third step is 1 g/L-10 kg/L, and the concentration range of the surfactant dissolved in the solvent or the non-solvent is 0.005 g/L-5 g/L.

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

Further, the recrystallization temperature in the fifth step is 0-90 ℃.

Compared with the prior art, the invention has the following remarkable advantages:

1. according to the preparation system, the inner and outer micro-tubes which are parallel in the axial direction complete efficient mixing of the solution and the anti-solvent, the flow ratio is not limited, and the preparation of the multi-granularity explosive is easy to realize.

2. The system has the advantages of high explosive preparation speed, high yield, short research and development period, low energy and material consumption and low environmental pollution, and is very suitable for optimization and screening of experimental parameters in the explosive preparation process.

3. The system can simply connect recrystallization units in parallel, and realizes high-throughput screening and batch production.

Drawings

FIG. 1 is a schematic diagram of a micro-nano explosive preparation system based on a coaxial focusing micro-mixer.

FIG. 2 is a sample morphology of hexanitrostilbene obtained in example 1 of the present application.

Description of reference numerals:

1-steady flow driving unit, 2-high pressure fluid driving unit, 3-Y type joint, 4-recrystallization unit and 5-collection unit.

Detailed Description

The present invention is described in further detail below with reference to the attached drawing figures.

With reference to fig. 1, the micro-nano explosive preparation system based on the coaxial focusing micro-mixer comprises a fluid driving unit, a recrystallization unit, a post-processing unit and a connecting assembly. Wherein the fluid driving unit provides a flow driving force for the solvent and the non-solvent; the recrystallization unit comprises 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 for controlling the temperature in the explosive preparation process; the solvent and the non-solvent solution flow into a coaxial focusing micro-mixer of the recrystallization unit under the drive of the fluid drive unit, the solvent and the non-solvent solution are contacted and rapidly mixed in the coaxial focusing micro-mixer to generate an explosive suspension, the explosive suspension flows into a collection unit, and the collection unit is used for recovering the explosive suspension and collecting finished products.

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

The following examples are merely illustrative of the present invention and should not be construed as limiting thereof.

Example 1

Coaxial focusing preparation of hexanitrostilbene

The hexanitrostilbene explosive is prepared by adopting a preparation system based on a coaxial focusing micro-mixer. Preparing the hexanitrostilbene explosive by taking DMSO as a solvent and deionized water as a non-solvent. 3000mg HNS is dissolved in 300mL DMSO solvent, placed in a bottle and driven by a continuous steady flow driving device injection pump, the flow rate is set to be 8mL/min, and the non-solvent solution is driven by a high-pressure fluid driving device, and the flow rate is 160 mL/min. The recrystallization temperature was set at 25 ℃. And (3) starting a switch of the driving unit, enabling the solvent solution and the non-solvent solution to flow into the coaxial focusing micro-mixer under the driving of the steady flow driving device and the high-pressure fluid driving device respectively, enabling the solvent and the non-solvent to be in contact and quickly mixed to form a hexanitrostilbene explosive suspension, introducing the hexanitrostilbene explosive suspension flowing out of the micro-mixer into the collecting unit, and finally obtaining the hexanitrostilbene explosive particles. The morphology of the resulting HNS is shown in fig. 2.

Claims

1. a micro-nano explosive preparation system based on coaxial focusing micro-mixer, is characterized in that, comprises steady current drive unit, high-pressure fluid drive unit, comprises the recrystallization unit of coaxial focusing micro-mixer, collection unit and related connection components;

The coaxial focusing micromixer includes an inner microtube, an outer microtube and a "T" type tee joint; the "T" type tee joint is connected to the outer microtube, and the inner microtube is arranged on the "T" type tee joint and the outer the interior of microtubules;

The steady flow driving unit is followed by the internal microtube and provides the flow driving force for the solvent, and the high-pressure fluid driving unit is followed by a "T" type tee joint and provides the flow driving force for the non-solvent; the coaxial focusing micro-mixer passes the internal microtube to the flow driving force. The spray of the external microtube realizes the mixing of solvent and non-solvent to generate the explosive suspension; the collection unit is used to recover the explosive suspension and collect the finished product.

2. The system according to claim 1, further comprising 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 the "Y" joint. Two ports of a T" tee.

3. The system according to claim 2, wherein the recrystallization unit further comprises a temperature control device for controlling the temperature of the recrystallization.

4. The system according to claim 3, wherein 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 sealing tank. The gas in the high-pressure gas cylinder generates high pressure to drive the solution in the sealing tank to flow to the coaxial focusing micro-mixer along the connecting pipe.

5 . The system according to claim 1 , wherein the material of the inner microtubes and the outer microtubes is stainless steel, PTFE or glass, and the inner diameters of the inner microtubes and the outer microtubes range from 50 to 5000 μm. 6 .

6. The use of the system according to any one of claims 1-5, characterized in that it is used to prepare micro-nano explosives.

7. a kind of method that adopts the system described in any one of claim 1-5 to prepare micro-nano explosive, is characterized in that, comprises the steps:

Step 1: Determine the diameters of the inner microtubes and the outer microtubes of the coaxial focusing micromixer according to the crystallization characteristics of the desired recrystallized explosive;

Step 2: connect each unit of the preparation system;

Step 3: dissolve the explosive in the solvent, dissolve the surfactant in the solvent or non-solvent, and prepare solvent and non-solvent solutions;

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

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

Step 6: After the temperature is heated to the set temperature, the drive unit is turned on, and the solvent and the non-solvent solution are pushed into the coaxial focusing micro-mixer, and the solvent and the non-solvent are contacted and quickly mixed to generate an explosive suspension;

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

8. method according to claim 7 is characterized in that, the concentration scope that the explosive in the step 3 is dissolved in solvent is 1g/L～10kg/L, and the concentration scope that surfactant is dissolved in solvent or non-solvent is 0.005g /L～5g/L.

9. method according to claim 7, is characterized in that, the flow velocity scope of the solvent in step 4 is 0.1～60mL/min, the flow velocity scope of non-solvent is 1～500mL/min, the scope of non-solvent and solvent flow velocity ratio It is 0.017～5000.

10 . The method according to claim 7 , wherein the recrystallization temperature in step 5 is 0-90° C. 11 .