Efficient piperazine melt crystallization separation device

Abstract

The utility model relates to the technical field of melt crystallization equipment, and discloses an efficient piperazine melt crystallization separation device which comprises a crystallization kettle body and a sweating kettle body, and a gas distributor is arranged in an inner cavity of the crystallization kettle body and used for introducing nitrogen; nitrogen is introduced into the top of the sweating kettle body, and a filter screen is arranged in an inner cavity; the crystallization kettle body is connected with the sweating kettle body through a crystallization transfer pump, and the bottom of the sweating kettle body is connected with a mother liquor tank, a sweat tank and a finished product tank respectively. By adopting the device disclosed by the utility model, piperazine can be purified by adopting a melt crystallization mode according to the characteristic that the difference between piperazine (the melting point is 109 DEG C) and methyl piperazine (the melting point is minus 6 DEG C) is large, the purity of the obtained product is higher than that of a rectification separation mode, and the energy consumption is lower than that of the rectification separation mode.

Description

Technical Field

[0001] The utility model belongs to the technical field of melt crystallization equipment, and in particular relates to a high-efficiency piperazine melt crystallization separation device. Background Art

[0002] Piperazine, also known as hexahydropyrazine and p-diazepine, has a wide range of applications and can be used in the preparation of chemical and pharmaceutical intermediates, dyes, resins, plastics, surfactants, and rubber additives. Piperazine salts such as phosphate, sulfate, and citrate can be used to prevent and treat poultry parasites; at the same time, piperazine has a nitrogen heterocyclic structure commonly used in pharmaceutical chemistry, which has the ability to regulate the physical and chemical properties of drugs. Therefore, piperazine is also an important intermediate for psychotropic drugs (quinolone series), antihypertensive drugs (pulepene), antiallergic drugs, and antitussive drugs. Piperazine can also be used in the printing and dyeing industry. Dyes synthesized using piperazine have the effect of preventing printed and dyed fabrics from fading.

[0003] In the industrial production process, piperazine is often produced in a co-production manner, and the co-produced products include methylpiperazine, ethylpiperazine and triethylenediamine. When piperazine and methylpiperazine are co-produced, the separation of piperazine and methylpiperazine becomes a major problem, because the boiling point difference between piperazine (boiling point 148°C) and methylpiperazine (boiling point 138°C) is only 10°C, and methylpiperazine will be entrained in the piperazine extracted during distillation separation, that is, the purity of piperazine is not high. Existing piperazine preparation devices rarely consider the separation of piperazine and methylpiperazine. For example, patent number CN202311437944.0 "A preparation device and preparation method for high-purity pyrophosphate piperazine" cannot achieve piperazine melt crystallization separation. For this reason, it is urgent to provide a suitable separation device to obtain piperazine with higher purity. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a high-efficiency piperazine melt crystallization separation device which has a simple structure and is convenient to use.

[0005] In order to solve the above technical problems, the utility model provides a high-efficiency piperazine melt crystallization separation device, comprising: a crystallization kettle body and a sweating kettle body, wherein a crystallization kettle feed port and a tail gas outlet are arranged on the top of the crystallization kettle body, a crystallization kettle discharge port is arranged on the bottom, and a gas distributor is arranged at the lower part of the inner cavity; a crystallization thermometer sleeve is obliquely inserted on the crystallization kettle body; a sweating kettle feed port is arranged on the top of the sweating kettle body, a sweating kettle discharge port is arranged on the bottom, and a filter screen is arranged at the lower part of the inner cavity; a sweating thermometer sleeve is obliquely inserted on the sweating kettle body;

[0006] The crystallization kettle discharge port is connected to the sweating kettle feed port through a crystallization transfer pump;

[0007] The discharge port of the sweating kettle is connected to the mother liquid tank, the sweating liquid tank and the finished product tank respectively;

[0008] The body of the crystallization kettle and the body of the sweating kettle are both double-layer shell structures;

[0009] Thermometers are inserted into the crystallization thermometer sleeve and the sweating thermometer sleeve.

[0010] As an improvement of a high-efficiency piperazine melt crystallization separation device of the utility model:

[0011] The upper and lower parts of the outer shell of the crystallization kettle body are respectively provided with a refrigerant outlet and a refrigerant inlet, which are used to circulate the refrigerant into the jacket space of the double-layer shell of the crystallization kettle body;

[0012] The upper and lower parts of the outer shell of the sweating kettle body are respectively provided with a heat medium outlet and a heat medium inlet, which are used to circulate heat medium into the jacket space of the double-layer shell of the sweating kettle body.

[0013] As a further improvement of the high-efficiency piperazine melt crystallization separation device of the utility model:

[0014] The gas distributor comprises an annular air pipe, on the bottom surface of which air holes are evenly distributed at intervals, the air holes open downward, and the annular air pipe is fixedly connected to the inner wall of the crystallization kettle body through a support rod.

[0015] As a further improvement of the high-efficiency piperazine melt crystallization separation device of the utility model:

[0016] The annular air pipe is connected to the nitrogen generator through a third valve;

[0017] The feed port of the sweating kettle is connected to the nitrogen generator through a sixth valve.

[0018] As a further improvement of the high-efficiency piperazine melt crystallization separation device of the utility model:

[0019] The induction head of the thermometer in the crystallization thermometer sleeve is located at the center of the lower middle part of the cavity of the crystallization kettle and above the gas distributor;

[0020] The induction head of the thermometer in the sweating thermometer sleeve is located at the center of the lower middle part of the inner cavity of the sweating kettle body and above the filter screen.

[0021] As a further improvement of the high-efficiency piperazine melt crystallization separation device of the utility model:

[0022] A second valve is arranged on the pipeline between the crystallization kettle discharge port and the crystallization transfer pump, and a fifth valve is arranged on the pipeline between the crystallization transfer pump and the sweating kettle feed port.

[0023] A seventh valve is provided on the pipeline between the sweating kettle discharge port and the mother liquid tank, an eighth valve is provided on the pipeline between the sweating kettle discharge port and the sweat liquid tank, and a ninth valve is provided on the pipeline between the sweating kettle discharge port and the finished product tank.

[0024] As a further improvement of the high-efficiency piperazine melt crystallization separation device of the utility model:

[0025] The tail gas outlet is connected to the fourth valve;

[0026] The feed port of the crystallization kettle is connected to the first valve.

[0027] The beneficial effects of the utility model are mainly reflected in:

[0028] 1. The utility model uses melt crystallization to purify piperazine based on the large difference in melting points between piperazine (melting point 109°C) and methylpiperazine (melting point -6°C). The purity of the obtained product is higher than that of the distillation separation method, which can reach 99%;

[0029] 2. The utility model does not introduce solvent in the piperazine separation process, which saves energy consumption of solvent separation and is an environmentally friendly production process;

[0030] 3. The piperazine separation process of the utility model is operated at low temperature, which reduces energy consumption; the process and operating temperature are low, which reduces corrosion to the equipment, that is, reduces the fixed investment cost of the equipment;

[0031] 4. The utility model fills nitrogen at the bottom of the kettle during the crystallization process, and the turbulence acts as stirring, which speeds up the mass transfer and heat transfer in the crystallization process, improves the crystallization effect, and increases the crystallization rate;

[0032] 5. The utility model fills nitrogen at the top during the sweating process, which accelerates the solid-liquid separation process and improves the sweating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The specific implementation of the utility model is further described in detail below with reference to the accompanying drawings.

[0034] Figure 1 This is a schematic structural diagram of a piperazine melt crystallization separation device of the utility model;

[0035] Figure 2 for Figure 1 FIG. 1 is a schematic diagram of the enlarged structure of the gas distributor 16. FIG. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0037] Embodiment 1, a kind of high-efficiency piperazine melt crystallization separation device, such as Figure 1-2As shown, it includes a crystallization device 1, a crystal transfer pump 2, a sweating device 3 and a nitrogen generator 4. The liquid material containing piperazine (with a certain temperature) enters the crystallization device 1, is cooled to precipitate crystals, and then the semi-solid mixed liquid (or liquid containing crystals) is pumped to the sweating device 3 by the crystal transfer pump 2 for filtration, and the temperature is increased to sweat to remove impurities, and the temperature is continued to be increased to melt the piperazine crystals and collect them to complete the melt crystallization.

[0038] The crystallization device 1 comprises a crystallization kettle body 10 , a crystallization kettle feed port 11 , a crystallization kettle discharge port 12 , a refrigerant inlet 13 , a refrigerant outlet 14 , a crystallization thermometer sleeve 15 , a gas distributor 16 , an air inlet 17 , and an exhaust gas outlet 18 .

[0039] The crystallization kettle body 10 includes three parts: upper, middle and lower. The upper and lower parts are hemispherical or elliptical heads, and the middle part is a cylinder with upper and lower openings. The upper and lower heads and the middle cylinder are sealed and connected by welding. The upper, middle and lower parts of the crystallization kettle body 10 are double-layer shell structures. The space between the double-layer shells is a jacket layer for passing a refrigerant to cool the crystallization kettle material. A refrigerant outlet 14 and a refrigerant inlet 13 are respectively provided at the upper and lower parts of the outer shell of the crystallization kettle body 10 for circulating a refrigerant for heat exchange.

[0040] The crystallization kettle body 10 is placed vertically to drain the materials in the kettle. A crystallization kettle feed port 11 is provided at the center of the top, and the crystallization kettle feed port 11 is connected to an external crystallization feed pipeline through a first valve 111. A crystallization kettle discharge port 12 is provided at the bottom of the crystallization kettle body 10, and the crystallization kettle discharge port 12 is connected to a crystallization transfer pump 2 through a second valve 112. Both the crystallization kettle feed port 11 and the crystallization kettle discharge port 12 penetrate the double-layer shell of the crystallization kettle body 10 and are connected to the inner cavity of the crystallization kettle body 10. A gas distributor 16 is provided at the lower part of the crystallization kettle body 10. The gas distributor 16 includes an annular air pipe 161. Air holes 163 are evenly spaced on the bottom surface of the annular air pipe 161. The air holes 163 open downward. Nitrogen rises after coming out of the air holes 163 until it is discharged from the liquid surface. The air holes 163 are arranged at the bottom of the annular air pipe 161 to prevent liquid materials from entering the gas distributor 16 and forming crystals after cooling to block the air holes 163 and the pipeline. Four support rods 162 are provided around the circumference of the annular air pipe 161. The annular air pipe 161 is fixedly connected to the inner wall of the crystallization kettle body 10 through the support rods 162.

[0041] An air inlet 17 is provided on the lower shell of the crystallization kettle body 10. The air inlet 17 penetrates the double-layer shell of the crystallization kettle body 10 and is connected to the inner cavity of the crystallization kettle body 10. The annular air pipe 161 is connected to the air inlet 17 through a pipeline and then connected to the external nitrogen generator 4 through the third valve 113.

[0042] A crystallization thermometer sleeve 15 is obliquely inserted into the crystallization kettle body 10, one end of the crystallization thermometer sleeve 15 is located outside the crystallization kettle body 10, and the other end is located inside the crystallization kettle body 10 (that is, the crystallization thermometer sleeve 15 passes through the double-layer shell of the crystallization kettle body 10), and a thermometer is inserted in the crystallization thermometer sleeve 15. The induction probe of the thermometer is located at the center of the lower middle part of the inner cavity of the crystallization kettle body 10 and above the gas distributor 16, so that the crystallization temperature of the liquid in the crystallization kettle body 10 can be measured more accurately.

[0043] A tail gas outlet 18 is provided at the top of the crystallization kettle body 10 , next to the crystallization kettle feed port 11 , and the tail gas outlet 18 is connected to the tail gas treatment device through a fourth valve 114 .

[0044] The sweating device 3 includes a sweating kettle body 30, a sweating kettle feed port 31, a sweating kettle discharge port 32, a heat medium inlet 33, a heat medium outlet 34, a sweating thermometer sleeve 35, a filter screen 36, a mother liquid tank 37, a sweating liquid tank 38 and a finished product tank 39.

[0045] The structure of the sweating kettle body 30 is similar to that of the crystallization kettle body 10, which is a double-layer shell, including three parts: upper, middle and lower. The upper and lower parts are hemispherical or elliptical heads, and the middle part is a cylinder with upper and lower openings. The upper and lower heads and the middle cylinder are sealed and connected by welding.

[0046] The upper and lower parts of the outer shell of the sweating kettle body 30 are respectively provided with a heat medium outlet 34 and a heat medium inlet 33, which are used to circulate the heat medium into the jacket space of the double-layer shell to exchange heat with the material in the kettle. The sweating kettle body 30 is placed vertically to facilitate liquid discharge. A sweating kettle feed port 31 is provided at the center of the top of the sweating kettle body 30, and a tee is provided outside the sweating kettle feed port 31. The sweating kettle feed port 31 is connected to the tee through a pipeline and then divided into two paths. One path is connected to the crystallization kettle discharge port 12 after passing through the fifth valve 311 and the crystallization transfer pump 2, and the other path is connected to the nitrogen generator 4 through the sixth valve 312, and nitrogen and crystallized materials can be respectively introduced into the sweating kettle body 30.

[0047] A sweating kettle discharge port 32 is provided at the bottom of the sweating kettle body 30, and three receiving tanks are connected below the sweating kettle discharge port 32 for receiving materials of different components. Specifically, a four-way valve is provided below the sweating kettle discharge port 32 to divide the pipeline into three routes. The first route is connected to the mother liquid tank 37 through the seventh valve 313 to receive the filtered mother liquid; the second route is connected to the sweat tank 38 through the eighth valve 314 to receive the sweat generated during the sweating process; the third route is connected to the finished product tank 39 through the ninth valve 315 to receive the melted finished product.

[0048] A filter screen 36 is provided at the lower part of the inner cavity of the sweating kettle body 30. The filter screen 36 is embedded in a protruding groove on the inner wall of the sweating kettle body 30 to filter and retain the crystals to be sweated.

[0049] A sweating thermometer sleeve 35 is obliquely inserted into the sweating kettle body 30, one end of the sweating thermometer sleeve 35 is located outside the sweating kettle body 30, and the other end is located inside the sweating kettle body 30 (that is, the sweating thermometer sleeve 35 passes through the double-layer shell of the sweating kettle body 30), and a thermometer is inserted in the sweating thermometer sleeve 35. The sensing head of the thermometer is located at the center of the lower middle part of the inner cavity of the sweating kettle body 30 and above the filter 36, so that the sweating temperature of the piperazine crystals can be measured more accurately.

[0050] The specific method of using the utility model is as follows:

[0051] 1. Crystallization kettle feeding

[0052] Open the first valve 111 and the fourth valve 114, close the second valve 112 below the crystallization kettle discharge port 12, pump the piperazine-containing liquid material (with a certain temperature) into the crystallization kettle body 10, close the first valve 111, and keep warm for half an hour.

[0053] 2. Cooling crystallization

[0054] The external circulating refrigerant enters the double-layer shell of the crystallization kettle body 10 through the refrigerant inlet 13, and then flows out from the refrigerant outlet 14 to achieve cooling of the crystallization kettle body 10; the third valve 113 is opened, and nitrogen flows out from the bottom of the gas distributor 16, and then emerges upward. The rising airflow has a disturbing effect on the liquid, and the liquid in the kettle (semi-solid in the later stage of crystallization) is mixed by disturbance, that is, the airflow replaces the stirring, and the nitrogen filled leaves the tank body through the tail gas outlet 18 and goes to the tail gas treatment device; after the temperature drops to the final crystallization temperature, the material inside the crystallization kettle body 10 is a solid-liquid mixture, with more liquid and a certain fluidity, and it is kept warm for half an hour.

[0055] 3. Transfer the material from the crystallization kettle to the sweating kettle

[0056] Close the third valve 113 to stop nitrogen filling, open the second valve 112 below the crystallization kettle outlet 12 and the fifth valve 311 above the sweating kettle feed port 31, open the seventh valve 313 above the mother liquid tank 37, open the crystal transfer pump 2, pump the cooled piperazine crystal-containing material into the sweating kettle body 30, filter, and the filtrate flows into the mother liquid tank 37 below through the filter screen 36 and the sweating outlet 32, and the piperazine crystals are retained on the filter screen 36. After the transfer is completed, close the crystal transfer pump 2, close the second valve 112 and the fifth valve 311.

[0057] 4. Accelerate filtration

[0058] Open the sixth valve 312, fill the sweating kettle body 30 with nitrogen to accelerate the filtration of the mother liquid, and when there is no mother liquid dripping on the filter screen 36 (or only a small amount of mother liquid dripping), open the eighth valve 314 above the sweating tank 38 and close the seventh valve 313 above the mother liquid tank 37.

[0059] 5. Warming up and sweating

[0060] The circulating heat medium is passed into the double-layer shell of the sweating kettle body 30, and the heat medium is slowly heated at a certain heating rate to achieve the heating of the sweating kettle. During the heating process, impurities, methyl piperazine and dissolved piperazine continue to drip along the filter 36 and flow into the sweat tank 38, at which time the piperazine is purified; in order to speed up the sweating process, nitrogen is used to blow the crystals and liquid from top to bottom to speed up the dripping speed of the sweat, improve the sweating efficiency and crystal purity. When the internal temperature of the sweating kettle body 30 is 2-3°C lower than the melting point of piperazine (108°C), the heating is stopped and kept warm for 1 hour.

[0061] 6. Receive finished products

[0062] After the heat preservation is completed, the ninth valve 315 above the finished product tank 39 is opened, and the eighth valve 314 above the sweating liquid tank 38 is closed; the circulating heat medium introduced into the double-layer shell of the sweating kettle body 30 raises the temperature in the sweating kettle body 30 to 3-5°C higher than the boiling point of piperazine and keeps it warm, so that the crystalline piperazine melts and flows into the finished product tank 39 below until the finished product is collected. The crystallization kettle body 10 is cooled, the ninth valve 315 is closed, the sixth valve 312 is closed, the seventh valve 313 is opened, and the sweating kettle body 30 is ready for use.

[0063] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. An efficient piperazine melt crystallization separation device, characterized in that: The invention comprises a crystallization kettle body (10) and a sweating kettle body (30); the top of the crystallization kettle body (10) is provided with a crystallization kettle feed port (11) and an exhaust gas outlet (18), the bottom of the crystallization kettle body (10) is provided with a crystallization kettle discharge port (12), and the lower part of the inner cavity is provided with a gas distributor (16); a crystallization thermometer sleeve (15) is obliquely inserted on the crystallization kettle body (10); the top of the sweating kettle body (30) is provided with a sweating kettle feed port (31), the bottom of the sweating kettle body (30) is provided with a sweating kettle discharge port (32), and the lower part of the inner cavity is provided with a filter screen (36); a sweating thermometer sleeve (35) is obliquely inserted on the sweating kettle body (30); The crystallization kettle discharge port (12) is connected to the sweating kettle feed port (31) via a crystallization transfer pump (2); The sweating kettle discharge port (32) is connected to the mother liquid tank (37), the sweat liquid tank (38) and the finished product tank (39) respectively; The crystallization kettle body (10) and the sweating kettle body (30) are both double-layer shell structures; The crystallization thermometer sleeve (15) and the sweating thermometer sleeve (35) are both inserted with thermometers.

2. A high-efficiency piperazine melt crystallization separation device according to claim 1, characterized in that: The upper and lower parts of the outer shell of the crystallization kettle body (10) are respectively provided with a refrigerant outlet (14) and a refrigerant inlet (13) for circulating the refrigerant into the jacket space of the double-layer shell of the crystallization kettle body (10); The upper and lower parts of the outer shell of the sweating kettle body (30) are respectively provided with a heat medium outlet (34) and a heat medium inlet (33) for circulating heat medium into the jacket space of the double-layer shell of the sweating kettle body (30).

3. A high-efficiency piperazine melt crystallization separation device according to claim 2, characterized in that: The gas distributor (16) comprises an annular air pipe (161), on the bottom surface of which air holes (163) are evenly spaced and distributed, the air holes (163) open downward, and the annular air pipe (161) is fixedly connected to the inner wall of the crystallization kettle body (10) via a support rod (162).

4. A high-efficiency piperazine melt crystallization separation device according to claim 3, characterized in that: The annular air pipe (161) is connected to the nitrogen generator (4) via a third valve (113); The sweating kettle feed port (31) is connected to the nitrogen generator (4) via a sixth valve (312).

5. A high-efficiency piperazine melt crystallization separation device according to claim 4, characterized in that: The induction head of the thermometer in the crystallization thermometer sleeve (15) is located at the center of the lower middle part of the inner cavity of the crystallization kettle body (10) and above the gas distributor (16); The induction head of the thermometer in the sweating thermometer sleeve (35) is located at the center of the lower middle part of the inner cavity of the sweating kettle body (30) and above the filter screen (36).

6. A high-efficiency piperazine melt crystallization separation device according to claim 5, characterized in that: A second valve (112) is provided on the pipeline between the crystallization kettle discharge port (12) and the crystallization transfer pump (2), and a fifth valve (311) is provided on the pipeline between the crystallization transfer pump (2) and the sweating kettle feed port (31); A seventh valve (313) is provided on the pipeline between the sweating kettle discharge port (32) and the mother liquid tank (37), an eighth valve (314) is provided on the pipeline between the sweating kettle discharge port (32) and the sweat liquid tank (38), and a ninth valve (315) is provided on the pipeline between the sweating kettle discharge port (32) and the finished product tank (39).

7. A high-efficiency piperazine melt crystallization separation device according to claim 6, characterized in that: The tail gas outlet (18) is connected to the fourth valve (114); The crystallization kettle feed port (11) is connected to the first valve (111).

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