Sodium sulfate waste salt crystallization kettle

Abstract

The utility model relates to the technical field of chemical production equipment, and particularly discloses a sodium sulfate waste salt crystallization kettle which comprises a kettle body provided with a temperature adjusting interlayer, a medium coil pipe is arranged in the temperature adjusting interlayer, the medium coil pipe is communicated with a temperature control device through a pipeline, and a stirring mechanism and a temperature sensor are arranged in the kettle body. The multiple medium coils are arranged in the vertical direction, the water inlet ends of the multiple medium coils are all connected to the same water inlet pipe, the water outlet ends of the multiple medium coils are all connected to the same water outlet pipe, branch water inlet valves are arranged at the water inlet ends of the medium coils, and a main water inlet valve is arranged on the water inlet pipe. The temperature control device comprises a controller and cooling equipment electrically connected with the controller; the water inlet pipe is connected with cooling equipment through a low-temperature water supply pipe. The utility model aims to solve the problem that the crystal form of sodium sulfate waste salt crystals is influenced due to non-uniform temperature change in the kettle body when the temperature of the existing crystallization kettle is regulated and controlled.

Description

Technical Field

[0001] This utility model relates to the field of chemical production equipment technology, and in particular to a sodium sulfate waste salt crystallization kettle. Background Technology

[0002] In industrial production, the amount of industrial waste salts generated annually through various chemical, pharmaceutical, and pesticide manufacturing processes is staggering, reaching approximately 1.2 million tons per year. One common type of salt residue is sodium sulfate waste salt residue, typically containing no less than 60% (wt%). Due to the large amount of impurities in sodium sulfate waste salt residue, it cannot be directly used as an industrial raw material or auxiliary material. Furthermore, its high moisture content and tendency to caking further exacerbate the difficulty of disposing of it. Traditional methods utilize the principle that sodium sulfate's solubility in water reaches its maximum of 48 g / 100 mL at 40°C and is 4.9 g / 100 mL at 0°C. This involves first heating to dissolve the sodium sulfate, then cooling it to crystallize it, thus recovering sodium sulfate from the waste salt. However, this method produces irregularly shaped and aesthetically unappealing crystals. Our unit has independently developed a new method for recovering sodium sulfate waste salt. By controlling the solid-liquid ratio and employing a segmented control of the crystallization temperature—initially guiding crystallization followed by low-temperature crystallization—we achieve good crystal form and a high yield. While existing crystallization reactors are equipped with temperature control devices, including coils within the jacket, and a controller to regulate the temperature of the medium within the coils, the temperature change rate at the inlet is higher than at the outlet. This uneven cooling negatively impacts crystal formation. To meet the demands of industrial-scale processing, the existing crystallization reactor needs redesign to accommodate the segmented temperature control required for sodium sulfate waste salt crystallization. Utility Model Content

[0003] To address the shortcomings of existing technologies, the present invention provides a sodium sulfate waste salt crystallization kettle, which solves the problem of uneven temperature changes within the kettle during temperature control, thus affecting the crystal form of sodium sulfate waste salt crystals.

[0004] To solve the above problems, the technical solution adopted by this utility model is as follows: a sodium sulfate waste salt crystallization kettle, comprising a kettle body with a temperature-regulating jacket, a medium coil provided in the temperature-regulating jacket, the medium coil being connected to a temperature control device via a pipe, a stirring mechanism and a temperature sensor provided in the kettle body, multiple medium coils arranged vertically, the water inlet ends of the multiple medium coils being connected to the same water inlet pipe, the water outlet ends of the multiple medium coils being connected to the same water outlet pipe, each water inlet end of the medium coil being provided with a separate water inlet valve, and a main water inlet valve being provided on the water inlet pipe; the temperature control device includes a controller and a cooling device electrically connected to the controller; the water inlet pipe is connected to the cooling device via a low-temperature water supply pipe.

[0005] The technical principle and beneficial effects of this solution are as follows: When cooling of the crystallization vessel is required, the branch inlet valve and the main inlet valve are opened, and the circulating water, after being cooled by the cooling equipment, is sent to four medium coils through the inlet pipes. The four medium coils simultaneously cool different locations within the crystallization vessel. Due to the large number of medium coils and the relatively short travel time from the inlet to the outlet of each individual coil, the temperature difference between different locations within the crystallization vessel is reduced, thereby achieving uniform temperature control within the crystallization vessel. Secondly, depending on the liquid level in the reactor, several media coils can be opened. For example, if the liquid level in the crystallization reactor is below 50%, the media coils III and IV are the main ones that can cool the liquid in the crystallization reactor. In this case, it is only necessary to open the water inlet valves of media coils III and IV and close the water inlet valves of media coils I and II. The circulating water after being cooled by the cooling device will mainly cool the crystallization reactor by entering media coils III and IV, thereby reducing the workload of the cooling equipment and eliminating the need for heat exchange and cooling of the entire side wall of the crystallization reactor.

[0006] Furthermore, the vessel is also equipped with a turbidity sensor, and the temperature sensor and turbidity sensor are electrically connected to the controller.

[0007] When crystallizing sodium sulfate waste salt, the process involves first evaporating at room temperature to guide crystallization. After the long, strip-shaped crystals precipitate, the solution is placed in a low-temperature environment to continue crystallizing. Therefore, the presence of some crystals in the solution reduces its clarity. This change in clarity is detected by a turbidity sensor. The controller receives the signal from the turbidity sensor, and when the turbidity reaches a preset value, it controls the cooling equipment to cool the reactor to 5°C. This facilitates the crystallization of sodium sulfate solution at a low temperature, increases the sodium sulfate yield, and ensures that the sodium sulfate crystals exhibit an aesthetically pleasing oblique crystal shape.

[0008] Furthermore, a level gauge is installed inside the reactor, and a level display is installed outside the reactor to show the current liquid level. The level gauge and the level display are electrically connected. Operators can select the appropriate water inlet valve to open based on the liquid level displayed on the level display, eliminating the need for operators to open the reactor lid to observe the liquid level, thus simplifying operation.

[0009] Furthermore, the level gauge is electrically connected to the controller, and the water inlet valve is an electrically controlled valve also electrically connected to the controller. By cooperating with the controller, different water inlet valves can be opened at preset liquid levels, thereby achieving automatic on / off control of the water inlet valves based on the liquid level. No manual operation is required, making it more convenient to use.

[0010] Furthermore, an alarm is installed outside the vessel, which is electrically connected to a liquid level sensor. By cooperating with the controller, different inlet valves can be opened at preset liquid levels, thus achieving automatic on / off control of the inlet valves based on the liquid level. No manual operation is required, making it more convenient to use.

[0011] Furthermore, the temperature control device also includes a heating device, and the water inlet pipe is connected to the heating device through a high-temperature water delivery pipe. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of this embodiment. Detailed Implementation

[0013] The following detailed description illustrates the specific implementation method:

[0014] The reference numerals in the accompanying drawings include: vessel body 1, temperature regulating jacket 11, medium coil 12, water inlet pipe 13, water outlet pipe 14, branch water inlet valve 15, main water inlet valve 16, heating device 2, cooling device 3, temperature sensor 4, turbidity sensor 5, and level gauge 6.

[0015] Example 1 is basically as shown in the appendix. Figure 1The image shows a sodium sulfate waste salt crystallization kettle, comprising a kettle body 1 with a temperature-regulating jacket 11. The temperature-regulating jacket 11 contains medium coils 12, which are connected to a temperature control device via pipes. The kettle body 1 contains a stirring mechanism and a temperature sensor 4. Four medium coils 12 are arranged vertically, numbered I-IV from top to bottom. The number of medium coils 12 can be determined according to requirements. The water inlets of all four medium coils 12 are connected to the same water inlet pipe 13, and the water outlets of all the medium coils 12 are connected to the same water outlet pipe 14. Each water inlet of the medium coils 12 is equipped with a branch water inlet valve 15, and the water inlet pipe 13 is equipped with a main water inlet valve 16. The temperature control device includes a controller, and a heating device 2 and a cooling device 3 electrically connected to the controller. The water inlet pipe 13 is connected to the heating device 2 and the cooling device 3 via a high-temperature water supply pipe and a low-temperature water supply pipe, respectively. The temperature control device adopts an existing structure.

[0016] Heating device 2 includes a heating heat exchanger, whose hot-side inlet and outlet are connected to high-temperature water supply and return pipes, respectively. Its cold-side inlet and outlet are connected to the outlet pipe 14 and inlet pipe 13 of the coil via a high-temperature return pipe and a high-temperature delivery pipe, respectively, for heating the circulating water from the coil. The heated circulating water is then sent to the coil to cool the crystallizing vessel. Both the high-temperature return pipe and the high-temperature delivery pipe are equipped with heating regulating valves. Cooling device 3 includes a cooling heat exchanger, whose cold-side inlet and outlet are connected to chilled water supply and return pipes, respectively. Its hot-side inlet and outlet are connected to the outlet pipe 14 and inlet pipe 13 of the coil via a low-temperature return pipe and a low-temperature delivery pipe, respectively, for cooling the circulating water from the medium coil 12. The cooled circulating water is then sent to the medium coil 12 to cool the crystallizing vessel. Both the low-temperature return pipe and the low-temperature delivery pipe are equipped with cooling regulating valves. The controller has a built-in existing temperature control system that controls the temperature of the heating and cooling regulating valves based on the set temperature value and the temperature signal fed back from temperature sensor 4.

[0017] The reactor body 1 is also equipped with a turbidity sensor 5, and the temperature sensor 4 and turbidity sensor 5 are electrically connected to the controller. The turbidity sensor 5 detects the turbidity of the liquid in the reactor body 1 and converts it into an electrical signal, which is then sent to the controller. The controller controls the opening of the cooling regulating valve according to the received electrical signal, so that the temperature inside the reactor body 1 is reduced to the set value. When sodium sulfate waste salt crystallizes, it is first evaporated at room temperature to guide crystallization. After some crystals precipitate, it is placed in a low-temperature environment to continue crystallizing. Therefore, when some crystals are present in the solution, the clarity of the solution will decrease. The turbidity sensor 5 detects the change in the clarity of the solution. The controller receives the signal from the turbidity sensor 5. When the turbidity reaches the preset value, it controls the cooling device 3 to cool the reactor body 1, so that the temperature inside the reactor body 1 is reduced to 5°C. This facilitates the crystallization of sodium sulfate solution at low temperature, improves the sodium sulfate yield, and ensures that the sodium sulfate crystals present an aesthetically pleasing oblique crystal shape.

[0018] When the device is in use, and cooling of the crystallization vessel is required, the branch inlet valve 15 and the main inlet valve 16 are opened. The circulating water, cooled by the cooling device 3, is then sent to the four medium coils 12 through the inlet pipe 13. The four medium coils 12 simultaneously cool different parts of the crystallization vessel. Because there are many medium coils 12, and the time it takes for a single medium coil 12 to travel from the inlet to the outlet is relatively short, the temperature difference between different parts of the crystallization vessel is reduced, thereby achieving uniform temperature control within the crystallization vessel. Secondly, depending on the liquid level in the vessel 1, several media coils 12 can be opened. For example, if the liquid level in the crystallization vessel is less than 50%, the media coils 12III and 12IV are the main ones that can cool the liquid in the crystallization vessel. In this case, it is only necessary to open the water inlet valves 15 of media coils 12III and 12IV and close the water inlet valves 15 of media coils 12I and 12II. Thus, the circulating water cooled by the cooling device mainly cools the crystallization vessel by entering media coils 12III and 12IV, thereby reducing the workload of the cooling equipment 3 and eliminating the need for heat exchange and cooling of the entire side wall of the crystallization vessel.

[0019] The similarities between Example 2 and Example 1 will not be repeated here. The difference is that a level gauge 6 is also installed inside the vessel body 1, and a level display (not shown in the figure) is installed outside the vessel body 1 to display the current liquid level. The level gauge 6 is electrically connected to the level display. The operator can select the water inlet valve to open according to the liquid level displayed on the level display, without the need for the operator to open the lid to observe the liquid level in the crystallization vessel, which is convenient for the operator.

[0020] The level gauge 6 is also electrically connected to the controller, and the water inlet valve 15 is an electrically controlled valve and is also electrically connected to the controller. Through the cooperation of the level gauge and the controller, different water inlet valves can be opened at different preset liquid levels, thereby achieving automatic on / off control of the water inlet valve 15 according to the liquid level. No manual operation is required, making it more convenient to use.

[0021] An alarm is also installed outside the vessel body 1 (not shown in the figure), which is electrically connected to the liquid level sensor. When the liquid level sensor detects an abnormal liquid level, the alarm will sound, for example, if the liquid level in vessel body 1 is too low or higher than the warning line, so that relevant operators can handle the situation in a timely manner.

[0022] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A sodium sulfate waste salt crystallization kettle, comprising a kettle body with a temperature-regulating jacket, wherein a medium coil is provided within the temperature-regulating jacket, the medium coil is connected to a temperature control device via a pipe, and a stirring mechanism and a temperature sensor are provided within the kettle body, characterized in that: Multiple media coils are arranged vertically, and the inlet ends of the multiple media coils are all connected to the same inlet pipe, and the outlet ends of the multiple media coils are all connected to the same outlet pipe. Each inlet end of the media coil is equipped with a branch inlet valve, and the inlet pipe is equipped with a main inlet valve. The temperature control device includes a controller and a cooling device electrically connected to the controller. The inlet pipe is connected to the cooling device through a low-temperature water supply pipe.

2. The sodium sulfate waste salt crystallization kettle according to claim 1, characterized in that: The vessel is also equipped with a turbidity sensor, and the temperature sensor and turbidity sensor are electrically connected to the controller.

3. The sodium sulfate waste salt crystallization kettle according to claim 1, characterized in that: The vessel body is also equipped with a level gauge, and the vessel body is equipped with a level display for displaying the current liquid level height. The level gauge and the level display are electrically connected.

4. The sodium sulfate waste salt crystallization kettle according to claim 3, characterized in that: The level gauge is also electrically connected to the controller, and the water inlet valve is an electrically controlled valve and is electrically connected to the controller.

5. A sodium sulfate waste salt crystallization kettle according to claim 3, characterized in that: An alarm is also installed outside the vessel, and the alarm is electrically connected to the liquid level sensor.

6. The sodium sulfate waste salt crystallization kettle according to claim 1, characterized in that: The temperature control device also includes a heating device, and the water inlet pipe is connected to the heating device through a high-temperature water delivery pipe.

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