Continuous crystallization device for cooling crystallization of magnesium ammonium sulfate solution

Abstract

The utility model discloses a continuous crystallization device for cooling crystallization of an ammonium magnesium sulfate solution, which comprises a crystallizer, a circulating pump and a tubular heat exchanger, and is characterized in that a mother liquor inlet, a clear liquor outlet and a crystal substance discharge port are arranged on the crystallizer, the clear liquor outlet is connected with an inlet of the circulating pump, and an outlet of the circulating pump is connected with an inlet of the tubular heat exchanger. An outlet of the shell-and-tube heat exchanger is connected with a mother liquor inlet of the crystallizer; and the mother liquor inlet of the crystallizer is connected with mother liquor sent from the outside. The device disclosed by the utility model has the advantages of continuity, capability of controlling the size of crystals, difficulty in blockage of the crystallizer, convenience in operation and the like.

Description

Technical Field

[0001] The utility model belongs to the field of chemical industry and environmental protection, and relates to a continuous crystallization device for cooling and crystallizing magnesium ammonium sulfate solution. Background Art

[0002] In industrial production, cooling crystallization technology continues to develop and improve in order to meet the needs of different industries for specific crystals. For example, in the pharmaceutical industry, there are strict requirements on the purity and crystal form of drug crystals, which has promoted the progress of cooling crystallization technology in precise control.

[0003] The integrated cooling crystallizer coil heat exchanger is installed inside the crystallizer. The following problems may occur during operation: 1) Crystal quality problems: uneven crystal size distribution and agglomeration lead to poor product quality. 2) Equipment scaling: During long-term operation, dirt may be deposited on the wall of the device, affecting the heat exchange efficiency and equipment performance. The crystallizer is large and difficult to clean. 3) Temperature control problems: It is difficult to accurately control the cooling temperature, and temperature fluctuations may have an adverse effect on the crystallization process. 4) Stirring effect problems: Uneven stirring or inappropriate strength may lead to local concentration differences and affect the crystallization effect. 5) Blockage risk: Crystals may cause blockages in the discharge port and other parts, affecting continuous operation. Summary of the invention

[0004] The purpose of the utility model is to solve the problems of uneven crystal size distribution, equipment scaling affecting heat exchange efficiency and equipment performance and difficulty in cleaning, and crystals causing blockages at the discharge port and other parts in the cooling crystallization process of the above-mentioned background technology, and to provide a continuous crystallization device for cooling crystallization of magnesium ammonium sulfate solution. The utility model device has the advantages of being continuous, controllable crystal size, not easy to clog the crystallizer and easy to operate.

[0005] The utility model adopts the following technical solutions:

[0006] A continuous crystallization device for cooling and crystallizing magnesium ammonium sulfate solution comprises a crystallizer, a circulation pump and a tube-and-tube heat exchanger, wherein the crystallizer is provided with a mother liquor inlet, a clear liquor outlet and a crystallized product outlet, the clear liquor outlet is connected to the circulation pump inlet, the circulation pump outlet is connected to the inlet of the tube-and-tube heat exchanger, the outlet of the tube-and-tube heat exchanger is connected to the mother liquor inlet of the crystallizer, and the mother liquor inlet of the crystallizer is connected to the mother liquor sent from the outside.

[0007] The crystallizer is divided into four zones from top to bottom, namely, a clear liquid zone, a connection zone, a suspension zone and a coarse crystal zone. A central guide tube is installed inside the crystallizer. The upper port of the central guide tube is located on the upper surface of the crystallizer as the mother liquid inlet, and the lower port of the central guide tube is located between the suspension zone and the coarse crystal zone of the crystallizer.

[0008] The crystallizer has a structure and appearance in the clear liquid zone, the connection zone and the suspension zone that is a cylindrical tank body plus an inverted cone hopper. The clear liquid outlet is designed on the crystallizer tube wall in the clear liquid zone, and the clear liquid outlet is connected to the inlet of the circulation pump through a pipeline. The crystallized material discharge outlet is designed on the crystallizer tube wall in the suspension zone. The crystallizer has a hemispherical structure and appearance in the coarse crystal zone. A drain pipe is installed at the bottom of the coarse crystal zone, and a drain valve is installed on the drain pipe.

[0009] The pipeline at the inlet of the circulation pump is equipped with a tee, which is respectively connected to the clear liquid outlet of the clear liquid zone of the crystallizer, the mother liquid sent from the outside, and the inlet of the circulation pump.

[0010] The utility model also comprises a feed valve and a circulation valve. The feed valve is arranged between the inlet of the circulation pump and the three-way connection; and the circulation valve is arranged on the outlet pipeline of the tube-in-tube heat exchanger.

[0011] The bottom angle of the inverted cone hopper is 30° to 60°.

[0012] The material of the crystallizer is carbon steel, stainless steel or organic glass.

[0013] The refrigerant used in the shell and tube heat exchanger is: water, liquid nitrogen, liquid ammonia or ethylene glycol aqueous solution.

[0014] The beneficial effects of the utility model are as follows: the device of the utility model has the advantages of being continuous, being able to control the size of the crystals of the crystallized product, being difficult to block the crystallizer, and being easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the utility model.

[0016] In the figure: 1-crystallizer, 11-central guide tube, 12-clear liquid outlet, 13-crystallized material outlet, 14-drain valve, 15-first mother liquid valve, 16-second mother liquid valve, 17-third mother liquid valve, 2-circulating pump, 21-feed valve, 22-circulating valve, 3-shell-and-tube heat exchanger, 31-inlet, 32-outlet, 33-refrigerant inlet, 34-refrigerant outlet. DETAILED DESCRIPTION

[0017] The utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments, which is convenient for a clear understanding of the utility model, but they do not constitute a limitation on the utility model. The circulation pump 2 and the shell-and-tube heat exchanger 3 of the utility model are both existing structures and are directly purchased.

[0018] like Figure 1As shown, the utility model is a continuous crystallization device for cooling and crystallizing magnesium ammonium sulfate solution, comprising a crystallizer 1, a circulation pump 2, and a tube-and-tube heat exchanger 3, characterized in that: a mother liquid inlet, a clear liquid outlet 12, and a crystal discharge outlet 13 are provided on the crystallizer 1, and a pipeline at the inlet of the circulation pump 2 is provided with a tee, which is respectively connected with the clear liquid outlet 12 of the clear liquid zone of the crystallizer, the mother liquid sent from the outside, and the inlet of the circulation pump, and a feed valve 21 is installed between the inlet of the circulation pump and the tee; the outlet of the circulation pump 2 is connected with the inlet 31 of the tube-and-tube heat exchanger 3, and the outlet 32 ​​of the tube-and-tube heat exchanger 3 is connected with the mother liquid inlet of the crystallizer 1, a circulation valve 22 is installed on the outlet pipeline of the tube-and-tube heat exchanger 3, and the mother liquid inlet of the crystallizer 1 is connected with the mother liquid sent from the outside.

[0019] like Figure 1 As shown, the crystallizer 1 is divided into four zones from top to bottom: a clear liquid zone, a connecting zone, a suspension zone and a coarse crystal zone. A central guide tube 11 is installed inside the crystallizer 1. The upper port of the central guide tube 11 is located on the upper surface of the crystallizer 1 as the mother liquid inlet, and the lower port of the central guide tube 11 is located between the suspension zone and the coarse crystal zone of the crystallizer; the crystallizer in the clear liquid zone, the connecting zone and the suspension zone has a cylindrical tank body plus an inverted cone hopper shape, the crystallizer in the clear liquid zone has a cylindrical tank body, and in the connecting zone has a cylindrical tank body. The structural shape of the zone is an inverted cone hopper, and the angle of the cone bottom of the inverted cone hopper is 30°. The structural shape of the suspension zone is an inverted cone hopper, and the angle of the cone bottom of the inverted cone hopper is 60°. The structural shape of the coarse crystal zone is hemispherical; the clear liquid outlet 12 is designed on the wall of the crystallizer in the clear liquid zone, and the clear liquid outlet 12 is connected to the inlet of the circulating pump 2 through a pipeline. The crystal discharge port 13 is designed on the wall of the crystallizer in the suspension zone. An emptying pipe is installed at the bottom of the coarse crystal zone, and an emptying valve 14 is installed on the emptying pipe. The material of the crystallizer is carbon steel, and stainless steel or organic glass can also be used. The refrigerant used in the shell and tube heat exchanger is water, and liquid nitrogen, liquid ammonia or ethylene glycol aqueous solution can also be used.

[0020] like Figure 1 As shown, the specific use of the utility model device is as follows: the high-temperature mother liquor of magnesium ammonium sulfate enters the crystallizer 1 through the first mother liquor valve 15, the second mother liquor valve 16, and the central guide tube 11, the high-temperature mother liquor in the crystallizer is transported to the shell and tube heat exchanger 3 through the clear liquid outlet 12, the circulating pump feed valve 21, and the circulating pump 2 for heat exchange cooling, the refrigerant enters the shell and tube heat exchanger 3 through the refrigerant inlet 33 and is discharged from the refrigerant outlet 34, the cooled mother liquor enters the crystallizer 1 through the circulation valve 22 and the central guide tube 11, the precipitated magnesium ammonium sulfate crystals are discharged through the crystallization discharge outlet 13, and the magnesium ammonium sulfate product is obtained after dehydration and drying.

[0021] The equipment runs continuously for 24 hours. By switching the valves, the high-temperature mother liquor of magnesium ammonium sulfate is transported to the shell-and-tube heat exchanger 3 through the first mother liquor valve 15, the third mother liquor valve 17, the circulating pump feed valve 21, and the circulating pump 2 to clean the crystals and scale in the shell-and-tube heat exchanger 3 and the circulating pipeline. The cleaned solution enters the crystallizer 1 through the circulating valve 22 and the central guide tube 11 for crystallization.

[0022] The above examples describe the present invention in detail. Different modifications and changes within the scope of the present invention are all implementation plans of the present invention.

Claims

1. A continuous crystallization device for cooling crystallization of magnesium ammonium sulfate solution, comprising a crystallizer, a circulation pump, and a shell-and-tube heat exchanger, characterized in that: The crystallizer is provided with a mother liquor inlet, a clear liquor outlet and a crystallized material discharge outlet. The clear liquor outlet is connected to the circulation pump inlet, the circulation pump outlet is connected to the inlet of the shell and tube heat exchanger, the outlet of the shell and tube heat exchanger is connected to the mother liquor inlet of the crystallizer, and the mother liquor inlet of the crystallizer is connected to the mother liquor sent from the outside.

2. The continuous crystallization device for crystallization by cooling of magnesium ammonium sulfate solution according to claim 1, characterized in that: The crystallizer is divided into four zones from top to bottom, namely, a clear liquid zone, a connection zone, a suspension zone and a coarse crystal zone. A central guide tube is installed inside the crystallizer. The upper port of the central guide tube is located on the upper surface of the crystallizer as the mother liquid inlet, and the lower port of the central guide tube is located between the suspension zone and the coarse crystal zone of the crystallizer.

3. The continuous crystallization device for crystallization by cooling of magnesium ammonium sulfate solution according to claim 2, characterized in that: The crystallizer has a structure and appearance in the clear liquid zone, the connection zone and the suspension zone that is a cylindrical tank body plus an inverted cone hopper. The clear liquid outlet is designed on the crystallizer tube wall in the clear liquid zone, and the clear liquid outlet is connected to the inlet of the circulation pump through a pipeline. The crystallized material discharge outlet is designed on the crystallizer tube wall in the suspension zone. The crystallizer has a hemispherical structure and appearance in the coarse crystal zone. A drain pipe is installed at the bottom of the coarse crystal zone, and a drain valve is installed on the drain pipe.

4. The continuous crystallization device for crystallization by cooling of magnesium ammonium sulfate solution according to claim 2, characterized in that: The pipeline at the inlet of the circulation pump is equipped with a tee, which is respectively connected to the clear liquid outlet of the clear liquid zone of the crystallizer, the mother liquid sent from the outside, and the inlet of the circulation pump.

5. The continuous crystallization device for crystallization by cooling of magnesium ammonium sulfate solution according to claim 4, characterized in that: It also includes a feed valve and a circulation valve. The feed valve is installed between the inlet of the circulation pump and the tee; the circulation valve is installed on the outlet pipeline of the shell and tube heat exchanger.

6. The continuous crystallization device for crystallization by cooling of magnesium ammonium sulfate solution according to claim 3, characterized in that: The bottom angle of the inverted cone hopper is 30° to 60°.

7. The continuous crystallization device for crystallization by cooling of magnesium ammonium sulfate solution according to claim 1, characterized in that: The material of the crystallizer is carbon steel, stainless steel or organic glass.

8. The continuous crystallization device for crystallization by cooling of magnesium ammonium sulfate solution according to claim 1, characterized in that: The refrigerant used in the shell and tube heat exchanger is: water, liquid nitrogen, liquid ammonia or ethylene glycol aqueous solution.

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