A multi-stage continuous separation and recovery method for explosive-containing mixed solvent

Abstract

The present invention discloses a multi-stage continuous separation and recovery method for a mixed solvent containing explosives. By adopting a multi-stage short-range / molecular distillation method, the heating temperature is controlled at a relatively low temperature and the heating time is controlled within 2 minutes. There is no need to store a large amount of material, and safety accidents caused by solvent decomposition caused by high temperature and explosive explosion are effectively avoided. The method can realize the step-by-step recovery of multi-component solvents, effectively meet the reuse requirements of the recovered solvents, and is suitable for the recovery and separation of complex solvent systems.

Description

Technical Field

[0001] The invention relates to the technical field of solvent separation in explosive production, in particular to a multi-stage continuous separation and recovery method for a mixed solvent containing explosives. Background Art

[0002] The production process of certain explosives generates large quantities of dioxane / ethylene glycol waste streams containing soluble explosives. Recovering dioxane and ethylene glycol from these waste streams presents a significant challenge for process scale-up. Currently, the most effective method for separating mixed solvents is a multi-stage distillation process, which achieves intermittent separation of the different solvent components by continuously varying distillation conditions. This separation process inevitably requires high temperatures and prolonged heating, resulting in large reactors and limited processing capacity. These issues become more pronounced as the solvent composition increases. Furthermore, dioxane reacts with oxygen under prolonged exposure to light and heat to form peroxides, which can cause explosions. Ethylene glycol has a boiling point exceeding 200°C, necessitating high energy consumption for recovery. Furthermore, the concentration of large quantities of soluble explosives at high temperatures poses significant safety risks. Therefore, traditional kettle-type multi-stage distillation technology struggles to address the recovery of mixed solvents containing explosives.

[0003] Short-path / molecular distillation technology is widely used in the separation and recovery of heat-sensitive substances due to its low heating temperature, short material heating time, and the absence of the need for large amounts of solvent storage. However, due to the limitations of continuous material input and output, a single short-path / molecular distillation unit cannot achieve graded recovery of multiple solvents. Summary of the Invention

[0004] The purpose of the present invention is to solve the above problems and provide a multi-stage continuous separation and recovery method for mixed solvents containing explosives. In order to achieve the separate recovery of multiple mixed solvents containing explosives, the present invention uses dioxane / ethylene glycol as an example, adopts multi-stage short-range / molecular distillation series technology, controls the heating temperature to 45°C, and the heating time to within 2 minutes, effectively avoiding the generation of peroxides and safety accidents caused by explosive explosions, and can obtain dioxane with a purity of >0.93, a recovery rate of >98%, and a purity of >0.95

[0005] The recovery rate of ethylene glycol is >80%, and the waste liquid discharge in the explosives production process is reduced by 85%, effectively meeting the reuse demand of recovered solvents.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] A multi-stage continuous separation and recovery device for explosive-containing mixed solvents, which recovers solvents through multi-stage distiller, wherein each stage of the distiller comprises a tank body, the outer wall of the tank body being provided with a heating jacket, the top of the tank body being provided with a material distribution tray, the material distribution tray being connected to a feeder, a film scraper being provided below the material distribution tray, the film scraper being in clearance with the inner wall of the tank body, and the film scraper being connected to a motor via a transmission shaft; a condenser being provided in the middle of the tank body, a baffle being provided near the bottom of the tank body, a distillation tank being provided at the bottom of the tank body inside the baffle, and a residual liquid tank and a vacuum system being provided on the tank body outside the baffle;

[0008] The distance between the outer surface of the condenser and the inner wall of the distiller tank is no more than five times the molecular mean free path of the solvent to be recovered under the recovery and separation conditions;

[0009] The material distribution plate of any lower-stage distiller is connected to the residual liquid tank of the upper-stage distiller through a pipeline.

[0010] The multi-stage distiller has 2-4 stages.

[0011] Another aspect of the present invention provides a multi-stage continuous separation and recovery method for a mixed solvent containing explosives, comprising the following steps:

[0012] Step 1: Assemble a multi-stage distiller with a suitable heating area, turn on the heating function of the distiller and control the heating temperature; turn on the condensing device and control the condensing temperature; turn on the vacuum system and maintain a certain vacuum degree; start the scraper and adjust the speed of the scraper;

[0013] Step 2: adding a mixed solution containing explosives or explosive intermediates to a first-stage distiller, controlling the feed rate so that the material flows downward continuously under the action of gravity; using a film scraper to scrape the material into a uniform thin film, thereby separating and recovering the first fraction in the mixed solution;

[0014] Step 3: The residual liquid is continued to be added to the second-stage distiller, and the second fraction in the mixed liquid is separated and recovered by adjusting the equipment heating area, feed rate, scraper speed, heating temperature and system pressure;

[0015] Step 4: The residual liquid is added to the next stage distiller in sequence until all fractions are separated;

[0016] Step 5: The high-concentration explosive waste liquid remaining after solvent recovery is collected by using a liquid collection bottle or an automatic discharger, and then incinerated.

[0017] A further solution is that the parameters of any one-stage distiller are set as follows: the heating area is 0.06-2.00m 2The heating temperature is 45-70°C; the system pressure is 50-8000 Pa; the scraper speed is 150-320 rpm; and the condensation temperature is -10°C-20°C. The parameters of the distiller at each stage can be the same or different.

[0018] A further solution is that in step 2, the feed rate is 1-10 L / h.

[0019] A further solution is that in step 2, the explosive includes one or more of BTF, NTO, TATB, HMX, RDX, PETN, LLM-105, DAAF, PATO, TCTNB, and TETNB.

[0020] A further solution is that in step 2, the mixed solution refers to a combination of at least two miscible solvents, including DMSO / water, dioxane / ethylene glycol, sulfolane / water, and DMF / water, and the mixing ratio is arbitrary.

[0021] The present invention utilizes multiple short-path / molecular distillation units connected in series, each with a different heating area, feed rate, scraper speed, heating temperature, and system pressure. After the material flows through one short-path / molecular distillation unit, a solvent is separated and then pumped into the second short-path / molecular distillation unit, and so on. Finally, the residual solvent forms a high-concentration waste liquid containing explosives. With the exception of the final stage, all solvent components are fully recovered, which partially recovers the solvent.

[0022] When the explosive-containing mixed solvent passes through each stage of the short-range / molecular distillation equipment, the material is continuously fed in and out by pumping. The short-range / molecular distillation devices at each stage can work simultaneously, and the separation of all solvent components starts and ends at the same time, which is highly efficient.

[0023] The beneficial effects of the present invention are:

[0024] The multi-stage continuous separation and recovery method of a mixed solvent containing explosives of the present invention controls the heating temperature at a relatively low temperature and the heating time within 2 minutes by adopting a multi-stage short-range / molecular distillation method. There is no need to store a large amount of materials, and safety accidents caused by solvent decomposition caused by high temperature and explosive explosion are effectively avoided. The method can realize the step-by-step recovery of multi-component solvents, effectively meet the reuse requirements of the recovered solvents, and is suitable for the recovery and separation of complex solvent systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the practical drawings required in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 It is a schematic diagram of the connection of the two-stage distiller of the present invention.

[0027] Figure 2 It is a schematic diagram of the connection of the three-stage distiller of the present invention.

[0028] Figure 3 It is a schematic diagram of the connection of the four-stage distiller of the present invention.

[0029] Figure 4 It is a structural diagram of any distiller of the present invention. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] The dioxane / ethylene glycol waste liquid (dioxane:ethylene glycol = 3:2) containing 1% of explosive intermediates was passed through a two-stage short-range / molecular distillation device at a rate of 1.5 L / h. The first stage heating area was 0.20 m 2 , heating temperature 45 ℃, system pressure 4000Pa, scraper speed 280rpm, cooling temperature -2 ℃, can recover 106% of dioxane, purity 0.86; second stage heating area 0.10m 2 , heating temperature 60℃, system pressure 150Pa, scraper speed 250rpm, cooling temperature -10℃, 80% of ethylene glycol can be recovered with a purity of 0.98.

[0033] Example 2

[0034] The dioxane / ethylene glycol waste liquid (dioxane:ethylene glycol = 1:1) containing 1% of explosive intermediates was passed through a two-stage short-range / molecular distillation device at a rate of 1.2 L / h. The first stage heating area was 0.15 m 2, heating temperature 45 ℃, system pressure 5000Pa, scraper speed 280rpm, cooling temperature 5 ℃, can recover 98% of dioxane, purity 0.93; second stage heating area 0.10m 2 , heating temperature 60℃, system pressure 150Pa, scraper speed 250rpm, cooling temperature -10℃, 80% of ethylene glycol can be recovered with a purity of 0.95.

[0035] Example 3

[0036] The dioxane / ethylene glycol waste liquid (dioxane:ethylene glycol = 5:4) containing 1% of explosive intermediates was passed through a two-stage short-range / molecular distillation device at a rate of 1.8 L / h. The first stage heating area was 0.2 m 2 , heating temperature 50 ℃, system pressure 2000Pa, scraper speed 280rpm, cooling temperature 2 ℃, can recover 108% of dioxane, purity 0.85; second stage heating area 0.10m 2 , heating temperature 60℃, system pressure 150Pa, scraper speed 250rpm, cooling temperature -10℃, 80% of ethylene glycol can be recovered with a purity of 0.99.

[0037] Example 4

[0038] The dioxane / ethylene glycol waste liquid (dioxane:ethylene glycol = 17:3) containing 1% of explosive intermediates was passed through a two-stage short-range / molecular distillation device at a rate of 1.5 L / h. The first stage heating area was 0.15 m 2 , heating temperature 50 ℃, system pressure 8000Pa, scraper speed 320rpm, cooling temperature 2 ℃, can recover 100% of dioxane, purity 0.93; second stage heating area 0.06m 2 , heating temperature 60℃, system pressure 150Pa, scraper speed 250rpm, cooling temperature -10℃, 80% of ethylene glycol can be recovered with a purity of 0.95.

[0039] Example 5

[0040] The sulfolane wastewater containing 1% BTF (sulfolane: water = 1:1) was passed through a two-stage short-path / molecular distillation device at a rate of 1 L / h. The first stage heating area was 0.15 m 2 , heating temperature 45 ℃, system pressure 2000Pa, scraper speed 280rpm, cooling temperature 2 ℃, can recover 99% of water, purity 0.99; second stage heating area 0.15m 2 , heating temperature 60℃, system pressure 50Pa, scraper speed 250rpm, cooling temperature 20℃, 85% of sulfolane can be recovered with a purity of 0.99.

[0041] Example 6

[0042] like Figure 1-2 As shown, a multi-stage continuous separation and recovery device containing explosive mixed solvent of the present invention is used to recover solvent through a multi-stage distiller. The distiller at any stage includes a tank body, the inner wall of the tank body is provided with a heating jacket 2, the top of the tank body is provided with a distribution tray 5, the distribution tray 5 is connected to the feeder 1, and a film scraper 7 is provided below the distribution tray 5. The film scraper 7 is in clearance with the inner wall of the tank body and is connected to the motor 4 through a transmission shaft; a condenser 6 is provided in the middle of the tank body, a baffle is provided near the bottom of the tank body, a distillation tank 9 is provided at the bottom of the tank body inside the baffle, and a residual liquid tank 3 and a vacuum system 8 are provided on the tank body outside the baffle;

[0043] The distance between the outer surface of the condenser and the inner wall of the distiller tank is no more than five times the molecular mean free path of the solvent to be recovered under the recovery and separation conditions;

[0044] The material distribution plate of any lower-stage distiller is connected to the residual liquid tank of the upper-stage distiller through a pipeline.

[0045] The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner unless there is any contradiction. In order to avoid unnecessary repetition, the present invention will no longer describe various possible combinations separately. In addition, the various different embodiments of the present invention can also be arbitrarily combined. As long as they do not violate the ideas of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A multi-stage continuous separation and recovery method for explosive-containing mixed solvents, characterized in that: A multi-stage continuous separation and recovery device containing explosive mixed solvent is adopted, and solvent recovery is carried out through a multi-stage distiller, wherein the distiller at any stage comprises a tank body, the outer wall of the tank body is provided with a heating jacket, the top of the tank body is provided with a distribution plate, the distribution plate is connected to a feeder, a film scraper is provided below the distribution plate, the film scraper is in clearance with the inner wall of the tank body, and the film scraper is connected to a motor through a transmission shaft; a condenser is provided in the middle of the tank body, a baffle is provided near the bottom of the tank body, a distillation tank is provided at the bottom of the tank body inside the baffle, and a residual liquid tank and a vacuum system are provided on the tank body outside the baffle; the outer surface of the condenser is not more than five times the molecular mean free path of the solvent to be recovered under recovery and separation conditions from the inner wall of the distiller tank; the distribution plate of any lower-stage distiller is connected to the residual liquid tank of the upper-stage distiller through a pipeline; The multi-stage continuous separation and recovery method of explosive-containing mixed solvent specifically includes: Step 1: Assemble a multi-stage distiller with a suitable heating area, turn on the heating function of the distiller and control the heating temperature; turn on the condensing device and control the condensing temperature; turn on the vacuum system and maintain a certain vacuum degree; start the scraper and adjust the speed of the scraper; Step 2: adding a mixed solution containing explosives or explosive intermediates to a first-stage distiller, controlling the feed rate so that the material flows downward continuously under the action of gravity; using a film scraper to scrape the material into a uniform thin film, thereby separating and recovering the first fraction in the mixed solution; Step 3: The residual liquid is continued to be added to the second-stage distiller, and the second fraction in the mixed liquid is separated and recovered by adjusting the equipment heating area, feed rate, scraper speed, heating temperature and system pressure; Step 4: The residual liquid is added to the next stage distiller in sequence until all fractions are separated; Step 5: After the solvent is recovered, the residual high-concentration explosive waste liquid is collected by a liquid collection bottle or an automatic discharger, and then incinerated; In step 2, the mixed solution is dioxane / ethylene glycol, and the mixing ratio is any ratio; In step 1, the parameters of any one-stage distiller are set as follows: the heating area is 0.06-2.00m 2 ; The heating temperature is 45-70°C; the system pressure is 50-8000Pa; the scraper speed is 150-320rpm; the condensation temperature is -10°C-20°C.

2. The multi-stage continuous separation and recovery method of a mixed solvent containing explosives according to claim 1, wherein: In step 2, the feed rate is 1-10 L / h.

3. The multi-stage continuous separation and recovery method of a mixed solvent containing explosives according to claim 1, wherein: In step 2, the explosives include one or more of BTF, NTO, TATB, HMX, RDX, PETN, LLM-105, DAAF, TCTNB, and TETNB.

4. The multi-stage continuous separation and recovery method of a mixed solvent containing explosives according to claim 1, characterized in that: The multi-stage distiller has 2-4 stages.

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