Device and method for continuously recycling organic alkali

Abstract

To provide a device and a method for continuously recycling organic alkali.SOLUTION: According to the invention, inline mixing, rapid neutralization, inline separation and continuous dewatering and drying are adopted, and a feeding pump, a micro-mixer, a micro-channel reactor, a liquid-liquid separator and a continuous stirring kettle are connected in sequence, so that inline recycling and reuse of an organic alkali in an alkali-containing waste liquid are achieved.EFFECT: By means of this full-continuous inline alkali recovery device, an organic alkali with reliable recovery quality can be obtained at a high recovery rate and can be directly reused without batch additional treatment, and the device has a high degree of integration, occupies a small floor area and has good operation stability, and such defects are avoided that a large floor area is occupied and recovery efficiency is low because a plurality of standing tanks and storage tanks need to be used in a kettle-type process.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of fine chemicals, and more particularly to an apparatus and method for continuous recovery and reuse of organic alkali. [Background technology]

[0002] Organic alkalis are often used as catalysts or acid binders in condensation and substitution reactions. They are reagents used in large quantities in synthetic reactions. After the reaction is complete, complex salts are often formed with hydrochloric acid, sulfuric acid, or phosphoric acid. These complex salts dissolve in water during post-extraction treatment, resulting in the generation of large amounts of organic alkali-containing wastewater. These organic alkali-containing wastewaters are not only difficult to treat, but also costly and consume large amounts of organic alkali. Therefore, extracting, recovering, and reusing organic alkalis from organic alkali-containing wastewater is a necessary measure to reduce chemical waste emissions and lower production costs.

[0003] Prior art documents such as CN218951289U, CN103304423B, CN103304423A, and CN208104264U provide recovery processes and equipment for triethylamine recovery. However, these require numerous storage tanks and settling tanks, occupying large floor space and resulting in low recovery efficiency. Alternatively, they require the use of a constant boiling distillation column to achieve continuous triethylamine recovery, resulting in high energy consumption and high recovery costs. Therefore, there is an urgent need to develop an innovative system specifically designed for the efficient recovery and reuse of organic alkali in liquid separation. Such a system can optimize recovery rates, simplify operation, ensure the purity of the recovered alkali, and allow for direct reuse, while reducing potential safety risks, thereby achieving a win-win situation for both environmental protection and economic benefits. Summary of the Invention

[0004] In view of the problems existing in the prior art, the object of the present invention is to provide an apparatus and method for continuous recovery and reuse of organic alkali with high recovery efficiency and low operating costs.

[0005] The organic alkali continuous recovery and reuse device and method provided by the present invention, by sequentially connecting a matching feed pump, micro-mixer, microchannel reactor, liquid-liquid separator and continuous kettle according to the characteristics of the reaction process, has a high alkali recovery rate (over 99%), high alkali recovery purity and can be reused as is, without the need for additional patch-type treatment, a high level of integration, a small occupied floor space and high operational stability, and avoids the shortcomings such as the large occupied floor space and low recovery efficiency that are required in kettle-type processes due to the need to use multiple stationary tanks and storage tanks.

[0006] The method for continuous organic alkali recovery and reuse provided by the present invention uses a fully continuous organic alkali in-line recovery and drying device, which is composed of one microchannel reactor, one continuous liquid-liquid separator, and one continuous vessel connected in series according to the alkali recovery process, and includes the following steps: (1) A first alkaline solution 1 (waste liquid; transported by a third pump 3) obtained by reacting a previously prepared reaction material with an alkali 1 to be recovered and reused, followed by post-treatment, is thoroughly mixed with a second alkaline solution 2 transported by a first pump 1 in a micromixer, and then introduced into a microchannel reactor for alkalinization reaction, with the residence time controlled to 0.1-30 minutes and the temperature of the microchannel reactor controlled to 0-90°C. (2) The alkaline solution discharged from the microchannel reactor enters the continuous liquid-liquid separator, where it quickly separates into layers due to gravity settling. The lower layer is the aqueous solution of the second alkaline solution 2, which is reused as the second alkaline solution 2 after being concentrated to remove some of the water. The upper layer of the continuous liquid-liquid separator is the first alkaline solution 1, which contains a small amount of water. The first alkaline solution 1 is directly introduced into a continuous vessel equipped with a stirring device and a heat exchanger. After stirring, the water contained in the first alkaline solution 1 is adsorbed by a moisture remover inside the continuous vessel. The first alkaline solution 1 is then drawn off from the top outlet of the continuous vessel by a second pump connected by a pipe to a storage tank for the first alkaline solution 1, where it becomes the recovered alkali.

[0007] In the present invention, the first pump, the second pump, and the third pump are plunger pumps for transporting a solution.

[0008] In the present invention, the micromixer is specially designed, specifically a composite plate-type micromixer consisting of 15-18 diamond-shaped conduit mixing elements connected in series. As shown in Figure 2, the diamond-shaped conduits are fluid passages with circular or square cross sections, with cross-sectional dimensions (diameter or side length) of 100 μm-20 mm, fluid passage lengths of 1-100 cm, and applicable flow rates of 1-3000 mL / min, preferably 1-20 mm, 10-100 cm, and applicable flow rates of 1000-3000 mL / min, and made of one or a combination of materials selected from glass, polytetrafluoroethylene, stainless steel, Hastelloy, tantalum, and zirconium.

[0009] In the present invention, the microchannel reactor is a specially designed tubular microreactor equipped with a static mixing element. Specifically, its main body is a tubular cavity serving as a fluid passage, with a reactant inlet and outlet at both ends of the cavity, respectively. A series of U-shaped elements are arranged axially within the tubular cavity, and the outside of the cavity is a heat exchange fluid intervening layer through which a heat exchange fluid passes, with a heat exchange fluid inlet and outlet at both ends of the heat exchange fluid intervening layer, respectively (Figure 3). The fluid passage has a diameter of 100 μm-20 mm and a length of 1 m-5000 m, preferably 5 mm-20 mm and 1 m-5000 m, and is made of one or a combination of materials selected from glass, polytetrafluoroethylene, stainless steel, Hastelloy, tantalum, and zirconium.

[0010] In the present invention, the liquid-liquid separator is designed according to the gravity settling principle, and its main body is a vertically arranged cylindrical cavity, with an inlet for the material to be separated at the bottom of the cavity, a lower heavy phase outlet at the bottom of the cavity, and an upper light phase outlet at the top of the cavity. The outside of the cylindrical cavity is a heat exchange fluid intervening layer through which a heat exchange fluid passes, with a heat exchange fluid inlet at the bottom of the heat exchange fluid intervening layer and a heat exchange fluid outlet at the top of the heat exchange fluid intervening layer (Figure 4). The liquid-liquid separator has an inner diameter of 1-20 cm and a height of 1-200 cm, and is made of one or a combination of materials selected from glass, polytetrafluoroethylene, stainless steel, Hastelloy, tantalum, and zirconium.

[0011] In the present invention, the continuous kettle is a vertically arranged cylinder with an internal stirring blade and an external heat exchange jacket. The continuous kettle has a material inlet at the bottom and a material outlet at the top. The heat exchange jacket has a heat exchange fluid inlet at the bottom and a heat exchange fluid outlet at the top. The continuous kettle is filled with a moisture remover. The material inlet is connected to a continuous liquid-liquid separator via a pipe, and the material outlet is connected to a pump via a pipe (Figure 5). The kettle has an inner diameter of 5-1000 cm and a height of 5-1000 cm. The material is made of one or a combination of materials selected from glass, polytetrafluoroethylene, stainless steel, Hastelloy, tantalum, and zirconium.

[0012] In the present invention, the first alkaline liquid 1 is any one of liquid ammonia, triethylamine, trimethylamine, tributylamine, diethylamine, and N,N-diisopropylethylamine, the alkali 2 is any one of potassium carbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, and lithium hydroxide, and the moisture remover filled in the continuous kettle is one or a combination of potassium carbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium sulfate, magnesium sulfate, and a molecular sieve.

[0013] In the present invention, the temperature of the microchannel reactor is 0-90°C, and the residence time of the material is 0.1-30 min. Preferably, the temperature is 20-60°C, and the residence time of the material is 5-20 min.

[0014] The present invention further provides an organic alkali continuous recovery and reuse device, which comprises three transfer pumps, one micro-mixer, one micro-channel reactor, one continuous liquid-liquid separator, and one continuous vessel, connected in sequence according to a recovery process. The micro-mixer, micro-channel reactor, liquid-liquid separator, and continuous vessel are connected in sequence by piping, and a first pump 1 is used to introduce a second alkaline liquid into the micro-mixer, a second pump 2 is used to discharge the first alkaline liquid 1 from the continuous vessel and feed it into a storage tank through a pipeline, and a third pump 3 is used to introduce the first alkaline liquid 1 (waste liquid) from the storage tank into the micro-mixer, and the second alkaline liquid introduced by the first pump 1 and the first alkaline liquid 1 (waste liquid) introduced by the third pump are mixed in the micro-mixer. After that, it enters the microchannel reactor for alkalinity reaction, and the effluent from the microchannel reactor enters the liquid-liquid separator for liquid-liquid separation. Here, the second alkaline liquid is refluxed from the lower outlet of the liquid-liquid separator and, after being concentrated, is introduced into the second alkaline liquid storage pool for further use. The first alkaline liquid enters the continuous kettle from the upper outlet of the liquid-liquid separator through a pipeline and is treated in the continuous kettle, where the water contained in the first alkaline liquid is adsorbed and removed. The first alkaline liquid is discharged by the second pump and, after a series of treatments, enters the storage tank, and this process is repeated. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a flow chart of an apparatus and method for continuous recovery and reuse of organic alkali. [Figure 2] FIG. 1 is a structural schematic diagram of a plate-type micromixer connected in series in a circular fashion. [Figure 3] FIG. 1 is a structural schematic diagram of a tubular microreactor incorporating a square-shaped mixing element. [Figure 4] FIG. 1 is a structural schematic diagram of a continuous liquid-liquid separator. [Figure 5] FIG. 1 is a structural schematic diagram of a continuous kettle for removing water from recovered alkali.

[0016] Explanation of symbols In Figures 3 to 5, 1 - reactant inlet of the tubular microreactor, 2 - reactant outlet of the tubular microreactor, 3 - heat exchange fluid outlet of the tubular microreactor, 4 - heat exchange fluid inlet of the tubular microreactor, 5 - R-shaped member of the tubular microreactor, 6 - inlet of the material to be separated into the liquid-liquid separator, 7 - lower heavy phase outlet of the liquid-liquid separator, 8 - upper light phase outlet of the liquid-liquid separator, 9 - heat exchange fluid inlet of the liquid-liquid separator, 10 - heat exchange fluid outlet of the liquid-liquid separator, 11 - material inlet of the continuous kettle, 12 - material outlet of the continuous kettle, 13 - heat exchange fluid inlet of the continuous kettle, 14 - heat exchange fluid outlet of the continuous kettle, and 15 - moisture remover. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will now be further described with reference to examples.

[0018] Example 1 The trimethylamine salt waste liquid obtained by reacting pre-prepared reaction materials with trimethylamine (the alkali 1 to be recycled and reused) and then post-processing was thoroughly mixed with 20% sodium hydroxide solution transported by pump 1 in a micromixer and then introduced into a microchannel reactor for alkalinization. The residence time was 5 min, and the reactor temperature was controlled at 40°C. The alkalinized liquid entered a continuous liquid-liquid separator and rapidly separated into layers by gravity. The lower layer was an aqueous sodium hydroxide solution, which was concentrated to 20% by distillation to remove water and then reused. The upper layer of the continuous liquid-liquid separator was trimethylamine, containing a small amount of water, and introduced directly into a continuous kettle with stirring and heat exchange functions. Anhydrous sodium sulfate, a moisture remover, was added to the kettle. After stirring, the water contained in the trimethylamine was adsorbed. The trimethylamine was then withdrawn from the kettle's upper outlet by pump 2, which was connected to a pipe and sent to a trimethylamine storage tank for reuse. The recovery of trimethylamine was 95.1%, the purity was greater than 99%, and the water content was less than 0.1%.

[0019] Example 2 The triethylamine salt waste liquid obtained by reacting pre-prepared reaction materials with triethylamine (the alkali 1 to be recycled and reused) and then post-processing was thoroughly mixed with 20% potassium hydroxide solution transported by pump 1 in a micromixer and then introduced into a microchannel reactor for alkalinization. The residence time was 3 min, and the reactor temperature was controlled at 40°C. The alkalinized liquid entered a continuous liquid-liquid separator and rapidly separated into layers by gravity. The lower layer was an aqueous potassium hydroxide solution, which was concentrated to 20% by distillation to remove water and then reused. The upper layer of the continuous liquid-liquid separator was triethylamine containing a small amount of water, which was introduced directly into a continuous kettle with stirring and heat exchange functions. Anhydrous sodium sulfate, a moisture remover, was added to the kettle. After stirring, the moisture contained in the triethylamine was adsorbed. The triethylamine was then withdrawn from the kettle's upper outlet by pump 2, which was connected to a pipe and sent to a triethylamine storage tank for reuse. The recovery of triethylamine was 96.3%, the purity was greater than 99%, and the water content was less than 0.1%.

[0020] Example 3 The triethylamine salt waste liquid obtained by reacting pre-prepared reaction materials with triethylamine (the alkali 1 to be recycled and reused) and then post-processing was thoroughly mixed with 20% potassium hydroxide solution transported by pump 1 in a micromixer and then introduced into a microchannel reactor for alkalinization. The residence time was 3 min, and the reactor temperature was controlled at 40°C. The alkalinized liquid entered a continuous liquid-liquid separator and rapidly separated into layers by gravity. The lower layer was an aqueous potassium hydroxide solution, which was concentrated to 20% by distillation to remove water and then reused. The upper layer of the continuous liquid-liquid separator was triethylamine containing a small amount of water, which was introduced directly into a continuous kettle with stirring and heat exchange functions. Anhydrous potassium hydroxide, a moisture remover, was added to the kettle. After stirring, the water contained in the triethylamine was adsorbed. The triethylamine was then withdrawn from the kettle's upper outlet by pump 2, which was connected to a pipe and sent to a triethylamine storage tank for reuse. The recovery of triethylamine was 99.1%, the purity was greater than 99%, and the water content was less than 0.1%.

[0021] Example 4 The triethylamine salt waste liquid obtained by reacting pre-prepared reaction materials with triethylamine (the alkali 1 to be recycled and reused) and then post-processing was thoroughly mixed with 25% sodium hydroxide solution transported by pump 1 in a micromixer and then introduced into a microchannel reactor for alkalinization. The residence time was 4 min, and the reactor temperature was controlled at 35°C. The alkalinized liquid entered a continuous liquid-liquid separator directly and rapidly separated into layers by gravity. The lower layer was an aqueous sodium hydroxide solution, which was concentrated to 25% by distillation to remove water and then reused. The upper layer of the continuous liquid-liquid separator was triethylamine containing a small amount of water, which was introduced directly into a continuous kettle with stirring and heat exchange functions. Anhydrous sodium hydroxide, a moisture remover, was added to the kettle. After stirring, the water contained in the triethylamine was adsorbed. The triethylamine was then withdrawn from the kettle's upper outlet by pump 2, which was connected to a pipe and sent to a triethylamine storage tank for reuse. The recovery of triethylamine was 99.6%, the purity was greater than 99%, and the water content was less than 0.1%.

[0022] Example 5 The tributylamine salt waste liquid obtained by reacting pre-prepared reaction materials with tributylamine (the alkali 1 to be recycled and reused) and then post-processing was thoroughly mixed with 25% sodium hydroxide solution transported by pump 1 in a micromixer and then introduced into a microchannel reactor for alkalinization. The residence time was 4 min, and the reactor temperature was controlled at 35°C. The alkalinized liquid entered a continuous liquid-liquid separator directly and rapidly separated into layers by gravity. The lower layer was an aqueous sodium hydroxide solution, which was concentrated to 25% by distillation to remove water and then reused. The upper layer of the continuous liquid-liquid separator was tributylamine containing a small amount of water, which was introduced directly into a continuous reactor with stirring and heat exchange functions. Anhydrous sodium hydroxide, a moisture remover, was added to the reactor. After stirring, the moisture contained in the tributylamine was adsorbed. The tributylamine was then withdrawn from the upper outlet of the reactor by pump 2, which was connected to a pipe, and transferred to a tributylamine storage tank for reuse. The recovery of tributylamine was 99.8%, the purity was greater than 99%, and the water content was less than 0.1%.

[0023] Furthermore, any changes and modifications to the embodiments described in this specification based on the concept of the present invention, or equivalent structure or process conversions made in accordance with the contents of this specification and drawings, or direct or indirect application of the above technical means to other related technologies, are all included in the protection scope of the present invention.

Claims

1. A method for continuously recovering and reusing organic alkali using a completely continuous organic alkali in-line recovery and drying device, which comprises three transfer pumps, one micromixer, one microchannel reactor, one continuous liquid-liquid separator, and one continuous vessel, connected in sequence according to the alkali recovery process, The method includes the following steps (1) to (2): (1) A first alkaline liquid, which is a waste alkaline liquid obtained by reacting a previously prepared reaction material with a first alkali to be recovered and reused and then performing a post-treatment operation, and a second alkaline liquid transported by a first pump are thoroughly mixed in a micromixer, and then introduced into a microchannel reactor for alkalinization reaction, the residence time is controlled to 0.1-30 minutes, and the temperature of the microchannel reactor is controlled to 0-90°C; (2) The alkaline solution discharged from the microchannel reactor enters a continuous liquid-liquid separator, where it rapidly separates into layers by gravity settling. The lower layer is an aqueous solution of the second alkali, which is reused as the second alkali solution after being concentrated to remove some of the water. The upper layer of the continuous liquid-liquid separator is a first alkali solution containing a small amount of water. The first alkali solution is directly introduced into a continuous vessel equipped with a stirrer and a heat exchanger. The continuous vessel contains a moisture remover, and after stirring, the moisture contained in the first alkali solution is adsorbed. The first alkali solution is then drawn out by a second pump connected to the upper outlet of the continuous vessel by a pipe and transferred to a storage tank for the first alkali solution, where it becomes the recovered alkali, thereby realizing reuse.

2. 2. The method of claim 1, wherein the first pump, the second pump, and the third pump are plunger pumps for transporting a solution.

3. The method according to claim 1, wherein the micromixer is a composite plate-type micromixer having 15-18 diamond-shaped conduits connected in series as mixing elements, and the diamond-shaped conduits are fluid passages having a circular or square cross section, a cross-sectional size of 100 μm-20 mm, a length of 1-100 cm, and an applicable flow rate of 1-3000 mL / min.

4. 2. The method of claim 1, wherein the microchannel reactor is a tubular microreactor equipped with a static mixing element, specifically, the main body of the microchannel reactor is a tubular cavity serving as a fluid passage, and a reactant inlet and a reactant outlet are provided at both ends of the cavity, respectively. A series of U-shaped elements are provided in the tubular cavity along the axial direction. The outside of the cavity is a heat exchange fluid intervening layer through which a heat exchange fluid passes, and a heat exchange fluid inlet and a heat exchange fluid outlet are provided at both ends of the heat exchange fluid intervening layer, respectively. The diameter of the fluid passage is 100 μm-20 mm, and the length is 1 m-5000 m.

5. 2. The method of claim 1, wherein the liquid-liquid separator is a liquid-liquid separator designed according to the gravity settling principle, its main body being a vertically arranged cylindrical cavity, with an inlet for the material to be separated at the lower end of the cavity, a lower heavy phase outlet at the lower end of the cavity, and an upper light phase outlet at the upper end of the cavity, and a heat exchange fluid intervening layer outside the cylindrical cavity for passing a heat exchange fluid, with a heat exchange fluid inlet at the bottom of the heat exchange fluid intervening layer and a heat exchange fluid outlet at the top of the heat exchange fluid intervening layer, and the liquid-liquid separator has an inner diameter of 1-20 cm and a height of 1-200 cm.

6. 2. The method of claim 1, wherein the continuous kettle is a vertically arranged cylinder having an agitator blade disposed inside and a heat exchange jacket disposed outside, the continuous kettle having a material inlet at the bottom and a material outlet at the top, the heat exchange jacket having a heat exchange fluid inlet at the bottom and a heat exchange fluid outlet at the top, the continuous kettle being filled with a moisture remover, the material inlet being connected to a continuous liquid-liquid separator via a pipe, and the material outlet being connected to a pump via a pipe, the continuous kettle having an inner diameter of 5-1000 cm and a height of 5-1000 cm.

7. 2. The method of claim 1, wherein the first alkali is any one of liquid ammonia, triethylamine, trimethylamine, tributylamine, diethylamine, and N,N-diisopropylethylamine; the second alkali is any one of potassium carbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, and lithium hydroxide; and the moisture remover filled in the continuous kettle is one or a combination of potassium carbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium sulfate, magnesium sulfate, and a molecular sieve.

8. A continuous recovery and reuse apparatus for organic alkali, comprising three transport pumps, one micromixer, one microchannel reactor, one continuous liquid-liquid separator, and one continuous vessel, which are connected in sequence according to a recovery process, The micro-mixer, the micro-channel reactor, the liquid-liquid separator, and the continuous vessel are connected in sequence by piping, the first pump is used to introduce the second alkaline liquid into the micro-mixer, the second pump is used to discharge the first alkaline liquid in the continuous vessel and enter it into the storage tank through a pipeline, and the third pump is used to introduce the first alkaline liquid in the storage tank into the micro-mixer, and after the second alkaline liquid introduced by the first pump and the first alkaline liquid introduced by the third pump are mixed in the micro-mixer, the micro-channel reactor is the first alkaline solution flows into a continuous vessel through a pipe from the upper outlet of the liquid-liquid separator and is treated in the continuous vessel where water contained in the first alkaline solution is adsorbed and removed; the first alkaline solution is discharged by a second pump and, after a series of treatments, flows into a storage tank, and the circulation continues in this manner.

9. the first pump, the second pump, and the third pump are plunger pumps for transporting a solution; The micromixer is a composite plate-type micromixer in which 15-18 diamond-shaped conduits are connected in series, and the diamond-shaped conduits are fluid passages with circular or square cross sections, with a cross-sectional size of 100 μm-20 mm, a length of 1-100 cm, and an applicable flow rate of 1-3000 mL / min; The microchannel reactor is a tubular microreactor equipped with a static mixing element, specifically, a tubular cavity as a fluid passage, a reactant inlet and a reactant outlet are provided at both ends of the cavity, a series of U-shaped elements are provided along the axial direction within the tubular cavity, a heat exchange fluid intervening layer is provided on the outside of the cavity for the heat exchange fluid to pass through, a heat exchange fluid inlet and a heat exchange fluid outlet are provided at both ends of the heat exchange fluid intervening layer, the diameter of the fluid passage is 100 μm-20 mm, and the length is 1 m-5000 m; The liquid-liquid separator is a liquid-liquid separator designed according to the gravity settling principle, and its main body is a vertically arranged cylindrical cavity, with an inlet for the material to be separated at the lower end of the cavity, a lower heavy phase outlet at the lower end of the cavity, and an upper light phase outlet at the upper end of the cavity. The outside of the cylindrical cavity is a heat exchange fluid intervening layer through which a heat exchange fluid passes, with a heat exchange fluid inlet at the bottom of the heat exchange fluid intervening layer and a heat exchange fluid outlet at the top of the heat exchange fluid intervening layer. The liquid-liquid separator has an inner diameter of 1-20 cm and a height of 1-200 cm.

9. The apparatus of claim 8, wherein the continuous kettle is a vertically arranged cylinder having an agitator blade disposed inside and a heat exchange jacket disposed outside, a material inlet disposed at the bottom of the continuous kettle and a material outlet disposed at the top, a heat exchange fluid inlet disposed at the bottom of the heat exchange jacket and a heat exchange fluid outlet disposed at the top, the continuous kettle is filled with a moisture remover, the material inlet is connected to the continuous liquid-liquid separator by a pipe, and the material outlet is connected to the pump by a pipe, the continuous kettle has an inner diameter of 5-1000 cm and a height of 5-1000 cm.

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