An oxalic acid dissolving device

Abstract

This utility model discloses an oxalic acid dissolution device, which includes a dissolution tank, a water tank, a liquid pump, a heat exchanger, and water and gas circuits connecting the components. The dissolution tank has an inlet and an outlet, and a nitrogen blowing system at the bottom. The water tank supplies water to the dissolution tank through parallel heating water circuits, and the steam inflow is controlled by adjusting a steam valve, thereby controlling the heating. A first thermometer inside the dissolution tank monitors the solution temperature in real time, ensuring a constant temperature during the dissolution process. This device solves the problems of large temperature fluctuations, uneven dissolution, and easy oxidation in oxalic acid dissolution, significantly improving dissolution efficiency and product quality.

Description

Technical Field

[0001] This utility model relates to the field of chemical dissolution equipment technology, specifically to an oxalic acid dissolution device. Background Technology

[0002] Oxalic acid, also known as ethanedioic acid, is an important chemical raw material widely used in rare earth refining, metal cleaning, and pharmaceuticals. Its dissolution process presents the following technical challenges:

[0003] 1. Oxalic acid dissolution is an exothermic reaction. Too high a temperature can easily lead to decomposition, while too low a temperature will result in slow dissolution and easy crystallization. Precise temperature control is required.

[0004] 2. Oxalic acid has a high density and tends to accumulate at the bottom of the container, leading to excessively high local concentrations and crystallization.

[0005] 3. Oxalic acid solution is easily oxidized by oxygen at high temperatures and requires inert gas protection.

[0006] 4. Traditional dissolution is carried out by directly introducing steam, which places high demands on the dissolution tank, generally requiring a pressure vessel, and is therefore highly dangerous.

[0007] Traditional dissolving devices often use simple stirred tanks with direct steam heating, which suffers from problems such as low temperature control accuracy, high energy consumption, and uneven dissolution. Some devices use jacket heating, but the response speed is slow and cannot meet the dynamic temperature control requirements of exothermic reactions. Utility Model Content

[0008] The purpose of this invention is to overcome the defects in the existing technology and provide an oxalic acid dissolving device.

[0009] To achieve the above objectives, the technical solution of this utility model is to design an oxalic acid dissolving device, including a dissolving tank, a water tank, a liquid pump, and a heat exchanger. The dissolving tank is provided with an inlet and an outlet, and an outlet valve is provided at the outlet. The dissolving tank is provided with a first thermometer, and the heat exchanger is provided with a steam inlet and a steam outlet. The water tank and the heat exchanger are connected via a first pipe and a second pipe. The liquid pump and the second thermometer are located on either the first or second pipe. A first valve is provided on the first pipe, and a second valve is provided on the second pipe. The inlet pipe of the second valve is connected to the dissolving tank via a third pipe, and a third valve is provided on the third pipe. The outlet end of the first valve is connected to a fourth pipe, and the other end of the fourth pipe is connected to the dissolving tank. A fourth valve is provided on the fourth pipe. Through the first, second, third, and fourth pipes, the solution in the dissolving tank can be circulated. The connection of the heat exchanger enables the temperature control of the solution during the dissolution circulation process.

[0010] Furthermore, an exhaust port and an exhaust valve are provided at the bottom of the dissolving tank. The dissolving tank is connected to a nitrogen tank via a fifth pipe. A gas pump and a fifth valve are installed on the fifth pipe. A blowpipe is connected to the end of the fifth pipe and is located inside the dissolving tank. The dissolving tank is also provided with a sixth pipe and a sixth valve. The exhaust port is used to discharge internal air, the fifth pipe is used to input nitrogen into the dissolving tank to achieve nitrogen blowing and stirring of the internal solution, and the sixth pipe is used to discharge internal nitrogen.

[0011] Furthermore, the other end of the sixth pipe is connected to the outlet of the fifth valve on the fifth pipe. The connection between the sixth and fifth pipes is used to circulate internal nitrogen.

[0012] Furthermore, a heat exchanger is connected to the fifth pipe. The fifth pipe is a gas blowing pipe connected to the heat exchanger, which can control the gas temperature and prevent the gas temperature from dropping during circulation and affecting the overall melting temperature.

[0013] Preferably, the blowpipe is an annular distribution pipe, including an annular main pipe and a support pipe, which are connected by branch pipes. Ventilation holes are provided on the annular main pipe and the branch pipes. The annular distribution pipe type blowpipe can better purge the solution in the dissolving tank over a large area with multiple pores, resulting in a better blowing effect and improved dissolving speed and uniformity.

[0014] Preferably, the vent hole faces the bottom of the dissolving tank. Having the vent hole facing the bottom of the dissolving tank prevents the dissolved liquid from entering the blowpipe and causing blockage. Furthermore, having the vent hole facing downwards effectively blows up the dissolved liquid at the bottom, preventing clumping.

[0015] Furthermore, a third thermometer is installed on the fifth pipe. The third thermometer can monitor the temperature of the gas after it passes through the heat exchanger in real time, so as to adjust the gas flow rate and thus stabilize the temperature of the gas entering the dissolving tank.

[0016] Furthermore, a batch feeding device is provided at the inlet of the dissolving tank. The batch feeding device is preferably a screw feeder. The batch feeding device can achieve multiple small-batch controlled feedings, avoiding excessively high local concentrations, sudden temperature changes, or agglomeration caused by adding a large amount of oxalic acid at once, which is beneficial for uniform dissolution and temperature control.

[0017] Furthermore, a steam valve is installed at the steam inlet of the heat exchanger. The steam valve controls the entry and exit of steam in the heat exchanger, so that when the dissolution temperature is high, the heat exchanger will no longer circulate and heat the solution.

[0018] Furthermore, a weighing device is installed below the dissolving tank. The weighing device can accurately control the weight of the added oxalic acid solids and / or the weight of the solution in the tank, and calculate based on the water flow rate and the amount of oxalic acid solids to ensure that the solution concentration meets the requirements.

[0019] Preferably, the first valve, the second valve, the third valve, the fourth valve, the fifth valve, and the sixth valve are electromagnetic valves and are electrically connected to the controller. Liquid pumps, gas pumps, etc. are also electrically connected to the controller.

[0020] The advantages and beneficial effects of this utility model are as follows:

[0021] 1. Nitrogen purging provides effective bottom disturbance, solving the common problems of bottom sedimentation and temperature stratification in dissolving tanks.

[0022] 2. External circulation is adopted to improve dissolution efficiency and uniformity of the solution. The external circulation is connected to a heat exchanger to control the temperature of the solution during the circulation process, thereby improving dissolution efficiency.

[0023] 3. Nitrogen can replace the internal air, and the entire dissolution process takes place inside nitrogen, preventing oxalic acid from being oxidized by oxygen.

[0024] 4. By using external nitrogen circulation and external dissolving liquid circulation, it can be achieved under normal pressure, eliminating the need for pressure vessels and reducing the risk. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the dissolving device of this utility model;

[0026] Figure 2 This is a schematic diagram of the blowpipe structure of this utility model.

[0027] In the diagram: 1. Dissolving tank; 11. Inlet; 12. Outlet; 13. Outlet valve; 2. Water tank; 20. Liquid pump; 3. Heat exchanger; 31. Steam inlet; 32. Steam outlet; 33. Steam valve; 41. First pipe; 410. First valve; 42. Second pipe; 420. Second valve; 43. Third pipe; 431. Third valve; 44. Fourth pipe; 441. Fourth valve; 45. Fifth pipe; 451. Fifth valve; 46. Sixth pipe; 461. Sixth valve; 51. First thermometer; 52. Second thermometer; 53. Third thermometer; 60. Exhaust port; 61. Exhaust valve; 7. Nitrogen tank; 70. Gas pump; 8. Blowpipe; 81. Circular main pipe; 82. Support pipe; 83. Branch pipe; 84. Vent; 9. Batch feeding device; 10. Weighing device. Detailed Implementation

[0028] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0029] according to Figure 1 As shown, this utility model is an oxalic acid dissolving device, including a dissolving tank 1, a water tank 2, a liquid pump 20, and a heat exchanger 3. The dissolving tank 1 is provided with an inlet 11 and an outlet 12, and an outlet valve 13 is provided at the outlet 12. The dissolving tank 1 is provided with a first thermometer 51. The heat exchanger 3 is provided with a steam inlet 31 and a steam outlet 32. The water tank 2 and the heat exchanger 3 are connected by a first pipe 41 and a second pipe 42. The liquid pump 20 and the second thermometer 52 are provided on the first pipe 41 or the second pipe 42. The first pipe 41 is provided with a first valve 410, and the second pipe 42 is provided with a second valve 420. The liquid inlet pipe of the second valve 420 is connected to the dissolving tank 1 through a third pipe 43. The third pipe 43 is provided with a third valve 431. The liquid outlet end of the first valve 410 is connected to a fourth pipe 44, and the other end of the fourth pipe 44 is connected to the dissolving tank 1. The fourth pipe 44 is provided with a fourth valve 441.

[0030] The workflow is as follows: First, oxalic acid is added to the dissolving tank 1 through the inlet 11. Then, the first valve 410 and the second valve 420 are opened, and the liquid pump 20 is started. The third valve 431 and the fourth valve 441 are closed, allowing water in the water tank 2 to reach the heat exchanger 3 through the first pipe 41. The steam inlet 31 and the steam outlet 32 ​​of the heat exchanger 3 are connected to the steam pipeline in the plant. After passing through the heat exchanger 3, the water temperature gradually rises and returns to the water tank 2 through the second pipe 42 for circulation until the temperature displayed by the second thermometer 52 reaches the required temperature. Then, the second valve 420 is closed, and the third valve 431 is opened. At this time, the heated water... Water no longer flows back into water tank 2, but instead flows into dissolving tank 1 through third pipe 43, where it mixes with the oxalic acid in dissolving tank 1, dissolving the oxalic acid. Once the added water volume meets the requirements, first valve 410 and liquid pump 20 are closed. After some of the oxalic acid has dissolved, liquid pump 20 is restarted, and fourth valve 441 is opened. At this time, the dissolved solution is pumped out from fourth pipe 44, flows through part of first pipe 41 and second pipe 42, and then flows back into dissolving tank 1 through third pipe 43 until the oxalic acid is fully dissolved. During this process, the temperature of the dissolved solution is controlled by heat exchanger 3 to ensure a constant temperature throughout the dissolving process. After full dissolution, the oxalic acid solution flows out through discharge valve 13 at discharge port 12.

[0031] according to Figure 1As shown, in any embodiment, an exhaust port 60 is provided below the dissolving tank 1, and an exhaust valve 61 is provided at the exhaust port 60. The dissolving tank 1 is connected to a nitrogen tank 7 via a fifth pipe 45. A gas pump 70 and a fifth valve 451 are provided on the fifth pipe 45. A blowpipe 8 is connected to the end of the fifth pipe 45. The blowpipe 8 is located inside the dissolving tank 1. The dissolving tank 1 is also provided with a sixth pipe 46, and a sixth valve 461 is provided on the sixth pipe 46.

[0032] The difference between this embodiment and other embodiments is that, in order to achieve rapid and complete dissolution during the dissolution process, a nitrogen blowing device is added. The working process is as follows: First, open the exhaust valve 61 at the bottom of the dissolution tank 1, and start the gas pump 70 and the fifth valve 451. The nitrogen in the nitrogen tank 7 flows through the fifth pipe 45 and enters the dissolution tank 1 through the blowpipe 8. Because the density of nitrogen is less than that of air, the nitrogen rises and accumulates at the top of the dissolution tank 1, while the air below is discharged from the exhaust port 60 at the bottom, replacing the air with nitrogen. When the air is completely replaced, close the exhaust valve 61 and open the sixth valve 461, thereby forming a nitrogen circulation loop. At this time, the nitrogen enters the dissolution tank 1 from the fifth pipe 45 and then exits from the sixth pipe 46. Then, the water from the previous embodiment is introduced and the previous embodiment is executed. During this process, when the nitrogen enters, the blowpipe 8 can blow the oxalic acid solution in the dissolution tank 1, accelerate its dissolution, and prevent the oxalic acid at the bottom from clumping.

[0033] according to Figure 1 As shown, in any embodiment, the other end of the sixth pipe 46 is connected to the outlet of the fifth valve 451 on the fifth pipe 45. The difference between this embodiment and other embodiments is that the sixth pipe 46 is connected to the fifth pipe 45, thereby allowing the nitrogen discharged from the sixth pipe 46 to be recovered and reused for nitrogen purging circulation.

[0034] according to Figure 1 As shown, in any embodiment, a heat exchanger 3 is connected to the fifth pipe 45. The difference between this embodiment and other embodiments is that the heat exchanger 3 is connected to the fifth pipe 45. The heat exchanger 3 can heat the nitrogen gas to prevent its external circulation from causing a temperature drop, which would then affect the dissolution temperature when the nitrogen flows back into the dissolution tank 1.

[0035] according to Figure 2As shown, in any embodiment, the blowpipe 8 is an annular distributed pipe, including an annular main pipe 81 and a support pipe 82. The annular main pipe 81 and the support pipe 82 are connected by a branch pipe 83, and vent holes 84 are provided on the annular main pipe 81 and the branch pipe 83. The difference between this embodiment and other embodiments is that the blowpipe is an annular distributed pipe. The annular distributed pipe blowpipe can better sweep the solution in the dissolving tank 1 over a large area with multiple pores, which can achieve a better blowing effect and improve the dissolving speed and uniformity.

[0036] according to Figure 2 As shown, in any embodiment, the vent 84 faces the bottom surface of the dissolving tank 1. The difference between this embodiment and other embodiments is that the vent 84 facing the bottom surface of the dissolving tank 1 prevents the dissolved liquid from entering the blowpipe 8 and causing blockage. Furthermore, the downward-facing vent 84 effectively blows up the dissolved liquid at the bottom, preventing clumping.

[0037] according to Figure 1 As shown, in any embodiment, a third thermometer 53 is provided on the fifth pipe 45. The difference between this embodiment and other embodiments is that the third thermometer 53 can monitor the temperature of the gas after passing through the heat exchanger 3 in real time, so as to adjust the gas flow rate and thus stably control the temperature of the gas entering the dissolving tank 1.

[0038] according to Figure 1 As shown, in any embodiment, a batch feeding device 9 is provided at the inlet 11 of the dissolving tank 1. The difference between this embodiment and other embodiments is that the batch feeding device 9 enables multiple small-batch controlled feedings, avoiding excessively high local concentrations, sudden temperature changes, or clumping caused by adding a large amount of oxalic acid at once, which is beneficial for uniform dissolution and temperature control.

[0039] according to Figure 1 As shown, in any embodiment, a steam valve 33 is provided at the steam inlet 31 of the heat exchanger 3. The difference between this embodiment and other embodiments is that the steam valve 33 controls the entry and exit of steam in the heat exchanger 3, so that when the dissolution temperature is high, the heat exchanger 3 will no longer circulate and heat the solution by closing the steam valve 33.

[0040] according to Figure 1 As shown, in any embodiment, a weighing device 10 is provided below the dissolving tank 1. The difference between this embodiment and other embodiments is that the weighing device 10 can accurately control the weight of the added oxalic acid solid and / or the weight of the solution in the dissolving tank 1, and calculates the solution concentration by using the water inflow and the amount of oxalic acid solid to ensure that the solution concentration meets the requirements.

[0041] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. An oxalate dissolving device, characterized by, The system includes a dissolving tank (1), a water tank (2), a liquid pump (20), and a heat exchanger (3). The dissolving tank (1) is equipped with an inlet (11) and an outlet (12), and an outlet valve (13) is installed at the outlet (12). A first thermometer (51) is installed on the dissolving tank (1). The heat exchanger (3) is equipped with a steam inlet (31) and a steam outlet (32). The water tank (2) and the heat exchanger (3) are connected through a first pipe (41) and a second pipe (42). The liquid pump (20) and the second thermometer (52) are installed on the first pipe (41). 1) or the second pipe (42), the first pipe (41) is provided with a first valve (410), the second pipe (42) is provided with a second valve (420), the inlet pipe of the second valve (420) is connected to the dissolving tank (1) through a third pipe (43), the third pipe (43) is provided with a third valve (431), the outlet end of the first valve (410) is connected to a fourth pipe (44), the other end of the fourth pipe (44) is connected to the dissolving tank (1), and the fourth pipe (44) is provided with a fourth valve (441).

2. The oxalate dissolving device of claim 1, wherein The dissolving tank (1) is provided with an exhaust port (60) at the bottom and an exhaust valve (61) at the exhaust port (60). The dissolving tank (1) is connected to a nitrogen tank (7) through a fifth pipe (45) at the bottom. A gas pump (70) and a fifth valve (451) are provided on the fifth pipe (45). A blowpipe (8) is connected to the end of the fifth pipe (45). The blowpipe (8) is located inside the dissolving tank (1). The dissolving tank (1) is also provided with a sixth pipe (46). A sixth valve (461) is provided on the sixth pipe (46).

3. An oxalate dissolving device according to claim 2, characterized in that The other end of the sixth pipe (46) is connected to the outlet of the fifth valve (451) on the fifth pipe (45).

4. The oxalate dissolving device of claim 2, wherein A heat exchanger (3) is connected to the fifth pipe (45).

5. The oxalate dissolving device of claim 2, wherein The blowpipe (8) is an annular distribution pipe, including an annular main pipe (81) and a support pipe (82). The annular main pipe (81) and the support pipe (82) are connected by a branch pipe (83). Ventilation holes (84) are provided on the annular main pipe (81) and the branch pipe (83).

6. An oxalate dissolving device according to claim 5, wherein The vent (84) faces the bottom of the dissolving tank (1).

7. The oxalate dissolving device of claim 2, wherein A third thermometer (53) is installed on the fifth pipe (45).

8. The oxalate dissolving device of claim 1, wherein The dissolving tank (1) is equipped with a batch feeding device (9) at the inlet (11).

9. The oxalate dissolving device of claim 1, wherein A steam valve (33) is provided at the steam inlet (31) of the heat exchanger (3).

10. The oxalate dissolving device of claim 1, wherein A weighing device (10) is provided below the melting tank (1).

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