Low-energy-consumption ionic membrane caustic soda concentration system

Abstract

The utility model belongs to the technical field of caustic soda concentration, and particularly relates to a low-energy-consumption ionic membrane caustic soda concentration system which comprises an electrolytic bath, a raw material bin, an evaporator and a finished product bin, low-concentration materials are generated in the electrolytic bath through electrolysis and stored in the raw material bin, and the low-concentration materials in the raw material bin form concentrated materials through the evaporator and enter the finished product bin. A steam compressor is additionally arranged, the input end of the steam compressor is connected with a steam outlet of the evaporator, the output end of the steam compressor is connected with a steam inlet of the evaporator, and steam carried by the concentrated materials is compressed by means of the steam compressor and returns into the evaporator. According to the utility model, secondary steam is compressed by utilizing the steam compressor, electric energy is converted into heat energy, and the heated secondary steam returns to the evaporator again to heat and evaporate low-concentration materials, so that the latent heat of vaporization of the secondary steam is recycled, and the concentration cost of concentrated materials is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of caustic soda concentration, and in particular relates to a low-energy consumption ion membrane caustic soda concentration system. Background Art

[0002] Currently, the sodium hydroxide solution produced by ion-exchange membrane caustic soda is 32% in concentration. However, some companies need to purchase caustic soda with a concentration of 40%. Therefore, some companies need to further increase the concentration of the sodium hydroxide solution after purchasing the 32% sodium hydroxide solution.

[0003] When concentrating caustic soda, an evaporator is generally used to evaporate and concentrate the 32% concentration caustic soda. The resulting 40% concentration caustic soda is then cooled and stored in a finished product warehouse. This results in the waste of secondary steam generated during the concentration process and the heat carried by the 40% concentration caustic soda, increasing the concentrated preparation cost of the 40% concentration caustic soda. Utility Model Content

[0004] In order to solve the problems existing in the above-mentioned prior art, the utility model provides a low-energy consumption ion membrane caustic soda concentration system, which compresses the secondary steam by using a steam compressor, converts the electrical energy into thermal energy, and after heating, the secondary steam returns to the evaporator to heat the low-concentration material to evaporate, thereby achieving the recycling of the latent heat of vaporization of the secondary steam and reducing the concentration cost of the concentrated material.

[0005] The specific technical solution adopted in this utility model is:

[0006] A low-energy consumption ion-exchange membrane caustic soda concentration system comprises an electrolytic cell, a raw material bin, an evaporator and a finished product bin. Low-concentration material is generated by electrolysis in the electrolytic cell and stored in the raw material bin. The low-concentration material in the raw material bin is converted into concentrated material by means of the evaporator and enters the finished product bin. A steam compressor is also provided. The input end of the steam compressor is connected to the steam outlet of the evaporator, and the output end of the steam compressor is connected to the steam inlet of the evaporator. The steam carried by the concentrated material is compressed by means of the steam compressor and returned to the evaporator.

[0007] A heat exchanger is also provided between the evaporator and the finished product bin. The heat medium input end of the heat exchanger is connected to the concentrated material discharge port of the evaporator, the heat medium input end of the heat exchanger is connected to the finished product bin, the cold medium input end of the heat exchanger is connected to the electrolytic cell, and the cold medium output end of the heat exchanger is connected to the raw material bin.

[0008] The evaporator includes a cylinder, and the interior of the cylinder chamber is divided from bottom to top into a feeding zone, a heat exchange zone and a boiling zone by means of a heat exchange baffle and a boiling baffle. A steam inlet is provided on the surface of the cylinder in the heat exchange zone, and a heat exchange tube and a reflux tube are provided in the heat exchange zone. Low-concentration material enters the heat exchange tube along the feeding zone with the help of a circulation pump, and the low-concentration material in the heat exchange tube rises through the heat exchange zone to exchange heat with the steam and heat up and enters the boiling zone. The boiling zone is formed into a negative pressure with the help of a negative pressure compressor, and the heated low-concentration material boils and condenses in the boiling zone to form a concentrated material. The steam formed by the concentrated material is exhausted by means of the steam outlet at the top of the boiling zone, and the concentrated material is returned to the feeding zone by means of the reflux tube for discharge after exhaust.

[0009] The feeding area includes an inlet guide tube and a discharge guide tube. The inlet guide tube is sleeved in the discharge guide tube. The input end of the discharge guide tube is connected to the raw material bin by means of a circulation pump, the output end of the discharge guide tube is connected to the input end of the heat exchange tube, the input end of the discharge guide tube is connected to the output end of the reflux pipe, and a concentrated material discharge port is provided at the bottom of the discharge guide tube.

[0010] The feed guide tube is a funnel-shaped structure, wherein the wider side of the feed guide tube forms the output end of the feed guide tube, and the narrower side of the feed guide tube forms the input end of the feed guide tube.

[0011] The circulation pump includes a feed inlet, a circulation inlet and a circulation outlet. The feed inlet is connected to the raw material bin, the circulation outlet is connected to the input end of the feed guide tube, and the circulation inlet is connected to the circulation end of the discharge guide tube. The concentrated material in the discharge guide tube enters the feed guide tube with the help of the circulation pump and forms a circulating concentration.

[0012] A boiling guide tube is provided in the boiling zone, the bottom of the boiling guide tube is fixedly connected to the boiling baffle of the boiling zone, the output end of the heat exchange tube passes through the boiling baffle and is connected to the inner ring of the boiling guide tube, and the input end of the return pipe passes through the boiling baffle and is connected to the outer ring of the boiling guide tube.

[0013] The inner ring wall of the boiling guide tube is provided with a spiral guide plate in a vertical direction, and the low-concentration material rises in a spiral shape along the boiling guide tube with the help of the spiral guide plate.

[0014] The beneficial effects of the utility model are:

[0015] 1. The utility model is additionally provided with a steam compressor. Since the secondary steam generated during the material concentration process is not sufficient for the concentration of the next batch of low-concentration materials, the steam compressor is used to compress the secondary steam, convert the electrical energy into thermal energy, and increase the pressure and temperature of the secondary steam. After the temperature is raised, the secondary steam returns to the evaporator to heat the low-concentration material and evaporate it, thereby achieving the recycling of the latent heat of vaporization of the secondary steam and reducing the concentration cost of the concentrated material.

[0016] 2. The utility model is provided with a heat exchanger. The temperature of the low-concentration material generated by electrolysis is relatively low. Therefore, the heat exchanger is first used to exchange heat with the high-temperature concentrated material. The low-concentration material is heated up before entering the raw material bin. The heat of the concentrated material is recycled, thereby increasing the initial temperature of the low-concentration material when it enters the evaporator, reducing the heat required for the low-concentration material to reach the boiling point, and reducing the concentration cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the process flow diagram of this system;

[0018] Figure 2 Schematic diagram of the structure of the evaporator;

[0019] Figure 3 Schematic diagram of the top view of the evaporator;

[0020] Figure 4 This is a schematic diagram of the top view of the boiling draft tube;

[0021] In the attached figure, 1, steam inlet, 2, cylinder, 3, heat exchange baffle, 4, boiling baffle, 5, heat exchange tube, 6, reflux pipe, 7, circulation pump, 8, steam outlet, 9, feed guide tube, 10, discharge guide tube, 11, concentrated material discharge port, 12, feed inlet, 13, circulation inlet, 14, circulation outlet, 15, boiling guide tube, 16, spiral guide plate. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0023] Specific embodiments, such as Figure 1 As shown, the utility model provides a low-energy consumption ion membrane caustic soda concentration system, including an electrolytic cell, a raw material bin, an evaporator and a finished product bin. Low-concentration material is generated by electrolysis in the electrolytic cell and stored in the raw material bin. The low-concentration material in the raw material bin is formed into concentrated material with the help of the evaporator and enters the finished product bin. A steam compressor is also provided. The input end of the steam compressor is connected to the steam outlet 8 of the evaporator, and the output end of the steam compressor is connected to the steam inlet 1 of the evaporator. The steam carried by the concentrated material is compressed with the help of the steam compressor and returned to the evaporator.

[0024] When concentrating caustic soda, an evaporator is generally used to evaporate and concentrate the 32% concentration caustic soda. The resulting 40% concentration caustic soda is then dissipated and stored in a finished product warehouse. This results in the waste of secondary steam generated during the caustic soda concentration process and the heat carried by the 40% concentration caustic soda, increasing the concentrated preparation cost of the 40% concentration caustic soda.

[0025] Therefore, a steam compressor is added to the present invention. Since the secondary steam generated during the material concentration process is not sufficient for the concentration of the next batch of low-concentration materials, the steam compressor is used to compress the secondary steam, convert electrical energy into thermal energy, and increase the pressure and temperature of the secondary steam. After the temperature is raised, the secondary steam returns to the evaporator to heat the low-concentration material and evaporate it, thereby achieving the recycling of the latent heat of vaporization of the secondary steam and reducing the concentration cost of the concentrated material.

[0026] In addition, two compression steam engines are arranged in series in the present invention, providing a higher pressure ratio and temperature difference to meet the temperature requirements for concentrating the material in the evaporator.

[0027] like Figure 1 As shown, a heat exchanger is also provided between the evaporator and the finished product bin. The heat medium input end of the heat exchanger is connected to the concentrated material discharge port 11 of the evaporator, the heat medium input end of the heat exchanger is connected to the finished product bin, the cold medium input end of the heat exchanger is connected to the electrolytic cell, and the cold medium output end of the heat exchanger is connected to the raw material bin. In addition to generating secondary steam, the concentrated material itself also carries a large amount of heat, so a heat exchanger is provided. The low-concentration material generated by electrolysis has a lower temperature, so the heat exchanger is first used to exchange heat with the high-temperature concentrated material. After the low-concentration material is heated, it enters the raw material bin, recycling the heat of the concentrated material, thereby increasing the initial temperature of the low-concentration material when it enters the evaporator, reducing the heat required for the low-concentration material to reach the boiling point, and reducing the concentration cost.

[0028] like Figure 2-4As shown, the evaporator includes a barrel 2, and the chamber of the barrel 2 is separated from bottom to top into a feeding zone, a heat exchange zone and a boiling zone by a heat exchange baffle 3 and a boiling baffle 4. A steam inlet 1 is provided on the surface of the barrel 2 in the heat exchange zone, and a heat exchange tube 5 and a reflux tube 6 are provided in the heat exchange zone. The low-concentration material enters the heat exchange tube 5 along the feeding zone with the help of a circulation pump 7. The low-concentration material in the heat exchange tube 5 rises through the heat exchange zone to exchange heat with the steam and heats up and enters the boiling zone. The boiling zone is formed into a negative pressure with the help of a negative pressure compressor. The heated low-concentration material boils and concentrates in the boiling zone to form a concentrated material. The steam formed by the concentrated material is exhausted by the steam outlet 8 at the top of the boiling zone. After exhaust, the concentrated material returns to the feeding zone with the help of the reflux tube 6 for discharge. After heat exchange, the low-concentration material enters the heat exchange tube 5 with the help of the circulation pump 7, and the low-concentration material is continued to be heated by the steam in the heat exchange zone. However, the temperature at this time is not enough to make the material boil under normal pressure conditions. Therefore, the heated low-concentration material enters the boiling zone. The negative pressure environment in the boiling zone causes the low-concentration material to boil, thereby increasing the concentration of the low-concentration material and forming a concentrated material. The secondary steam formed during the concentration process in the boiling zone is recovered and recycled by the steam compressor through the steam outlet 8, and the condensed water formed by the primary steam during the heat exchange process in the heat exchange zone is sent to the electrolytic cell to participate in the electrolysis reaction.

[0029] like Figure 2 As shown, the feeding zone includes an inlet guide tube 9 and a discharge guide tube 10. The inlet guide tube 9 is sleeved within the discharge guide tube 10. The input end of the discharge guide tube 10 is connected to the raw material bin via a circulation pump 7, the output end of the discharge guide tube 10 is connected to the input end of the heat exchange tube 5, and the input end of the discharge guide tube 10 is connected to the output end of the return pipe 6. A concentrated material discharge port 11 is provided at the bottom of the discharge guide tube 10. The discharge guide tube 10 and the inlet guide tube 9 can separate low-concentration materials from concentrated materials. In addition, the concentrated materials in the discharge guide tube 10 and the low-concentration materials in the inlet guide tube 9 will generate heat exchange, improving the utilization rate of waste heat.

[0030] like Figure 2 As shown, the feed guide tube 9 has a funnel-shaped structure, the wider side of the feed guide tube 9 forms the output end of the feed guide tube 9, and the narrower side of the feed guide tube 9 forms the input end of the feed guide tube 9. The funnel-shaped output end of the feed guide tube 9 can play a buffering role to avoid backflow of materials in the heat exchange tube 5.

[0031] like Figure 2As shown, the circulation pump 7 includes a feed inlet 12, a circulation inlet 13 and a circulation outlet 14. The feed inlet 12 is connected to the raw material bin, the circulation outlet 14 is connected to the input end of the feed guide tube 9, and the circulation inlet 13 is connected to the circulation end of the discharge guide tube 10. The concentrated material in the discharge guide tube 10 enters the feed guide tube 9 with the help of the circulation pump 7 and forms a circulation concentration. When in use, the feed inlet 12 and circulation outlet 14 of the circulation pump 7 are first opened, and the circulation inlet 13 is closed to concentrate the low-concentration material once. If the generated concentrated material does not reach the required concentration, the feed inlet 12 is closed and the circulation inlet 13 is opened. The concentrated material will enter the circulation inlet 13 and flow back to the feed guide tube 9 by the circulation pump 7 for secondary concentration. After the final concentrated material meets the requirements, the feed inlet 12 is reopened to concentrate the next batch of low-concentration materials.

[0032] like Figure 2 and Figure 4 As shown, a boiling guide tube 15 is provided in the boiling zone. The bottom of the boiling guide tube 15 is fixedly connected to the boiling baffle 4 in the boiling zone. The output end of the heat exchange tube 5 passes through the boiling baffle 4 to communicate with the inner ring of the boiling guide tube 15, and the input end of the return pipe 6 passes through the boiling baffle 4 to communicate with the outer ring of the boiling guide tube 15. The boiling guide tube 15 in the present invention is 1100 mm high and has a regular hexagonal cross-section with a side length of 550 mm. By providing a taller and larger boiling guide tube 15 to separate the entrance and exit of the heat exchange tube 5 and the return pipe 6, sufficient space is provided for concentrating the concentrated material and discharging the secondary steam, preventing the low-concentration material in the heat exchange tube 5 that has just entered the boiling zone from flowing back along the return pipe 6 before it is concentrated. In addition, the boiling guide tube also serves as a guide, causing the boiling concentrated material to overflow from the boiling guide tube in a fountain-like manner and flow back along the return pipe 6.

[0033] like Figure 2 and Figure 4 As shown, the inner ring wall of the boiling guide tube is provided with a spiral guide plate 16 in the vertical direction. The low-concentration material rises in a spiral shape along the boiling guide tube with the help of the spiral guide plate 16. The spiral guide plate 16 can increase the walking path of the low-concentration material in the boiling guide tube, thereby improving the concentration effect of the low-concentration material.

Claims

1. A low-energy ion-exchange membrane caustic soda concentration system comprises an electrolytic cell, a raw material bin, an evaporator, and a finished product bin. Low-concentration material is generated by electrolysis in the electrolytic cell and stored in the raw material bin. The low-concentration material in the raw material bin is converted into concentrated material by the evaporator and enters the finished product bin. The system is characterized in that: A steam compressor is also provided, the input end of the steam compressor is connected to the steam outlet (8) of the evaporator, and the output end of the steam compressor is connected to the steam inlet (1) of the evaporator. The steam carried by the concentrated material is compressed by the steam compressor and returned to the evaporator.

2. A low-energy consumption ion-exchange membrane caustic soda concentration system according to claim 1, characterized in that: A heat exchanger is further provided between the evaporator and the finished product bin, wherein the heat medium input end of the heat exchanger is connected to the concentrated material discharge port (11) of the evaporator, the heat medium input end of the heat exchanger is connected to the finished product bin, the cold medium input end of the heat exchanger is connected to the electrolytic cell, and the cold medium output end of the heat exchanger is connected to the raw material bin.

3. A low-energy consumption ion-exchange membrane caustic soda concentration system according to claim 1, characterized in that: The evaporator comprises a barrel (2), wherein the chamber of the barrel (2) is divided from bottom to top into a feeding zone, a heat exchange zone and a boiling zone by means of a heat exchange baffle (3) and a boiling baffle (4); a steam inlet (1) is provided on the surface of the barrel (2) in the heat exchange zone; a heat exchange tube (5) and a return tube (6) are provided in the heat exchange zone; low-concentration material enters the heat exchange tube (5) along the feeding zone by means of a circulation pump (7); the low-concentration material in the heat exchange tube (5) rises through the heat exchange zone to exchange heat with the steam and heat up and enters the boiling zone; the boiling zone is formed into a negative pressure by means of a negative pressure compressor; the heated low-concentration material boils and concentrates in the boiling zone to form a concentrated material; the steam formed by the concentrated material is exhausted by means of a steam outlet (8) at the top of the boiling zone; and the concentrated material is exhausted and returned to the feeding zone by means of the return tube (6) for discharge.

4. A low-energy consumption ion-exchange membrane caustic soda concentration system according to claim 3, characterized in that: The feeding area includes an inlet guide tube (9) and a discharge guide tube (10), wherein the inlet guide tube (9) is sleeved in the discharge guide tube (10), the input end of the discharge guide tube (10) is connected to the raw material bin by means of a circulation pump (7), the output end of the discharge guide tube (10) is connected to the input end of the heat exchange tube (5), the input end of the discharge guide tube (10) is connected to the output end of the reflux pipe (6), and a concentrated material discharge port (11) is provided at the bottom of the discharge guide tube (10).

5. A low-energy consumption ion-exchange membrane caustic soda concentration system according to claim 4, characterized in that: The feed guide tube (9) is a funnel-shaped structure, wherein the wider side of the feed guide tube (9) forms the output end of the feed guide tube (9), and the narrower side of the feed guide tube (9) forms the input end of the feed guide tube (9).

6. A low-energy consumption ion-exchange membrane caustic soda concentration system according to claim 4, characterized in that: The circulation pump (7) comprises a feed inlet (12), a circulation inlet (13) and a circulation outlet (14); the feed inlet (12) is connected to the raw material bin; the circulation outlet (14) is connected to the input end of the feed guide tube (9); the circulation inlet (13) is connected to the circulation end of the discharge guide tube (10); the concentrated material in the discharge guide tube (10) enters the feed guide tube (9) with the help of the circulation pump (7) and forms a circulating concentration.

7. The low-energy consumption ion-exchange membrane caustic soda concentration system according to claim 3, characterized in that: A boiling guide tube (15) is provided in the boiling zone, the bottom of the boiling guide tube (15) is fixedly connected to the boiling baffle (4) of the boiling zone, the output end of the heat exchange tube (5) passes through the boiling baffle (4) and is communicated with the inner ring of the boiling guide tube (15), and the input end of the return pipe (6) passes through the boiling baffle (4) and is communicated with the outer ring of the boiling guide tube (15).

8. A low-energy consumption ion-exchange membrane caustic soda concentration system according to claim 7, characterized in that: The inner ring wall of the boiling guide tube (15) is provided with a spiral guide piece (16) in a vertical direction, and the low-concentration material rises in a spiral shape along the boiling guide tube (15) with the help of the spiral guide piece (16).

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