Online granularity-controllable sodium chloride crystallization experimental device

Abstract

The utility model discloses an online granularity-controllable sodium chloride crystallization experimental device which comprises a crystallization mother liquor tank, a feed pipe arranged at the top of the crystallization mother liquor tank, and a heating interlayer arranged at the bottom of the crystallization mother liquor tank and used for heating brine in the crystallization mother liquor tank, and is characterized by further comprising a pH meter for monitoring the pH of the brine in the crystallization mother liquor tank, the thermometer is used for monitoring the temperature of brine in the crystallization mother liquor tank, the stirring device is used for stirring the brine in the crystallization mother liquor tank, and the vacuumizing pipe is arranged at the top of the crystallization mother liquor tank and communicated with the crystallization mother liquor tank. The online particle size monitoring device comprises a particle size monitoring probe which is arranged at the bottom in the crystallization mother liquor tank and is used for monitoring crystal particle size distribution data, and a host connected with the particle size monitoring probe. The utility model solves the problems that the frequent sampling and granularity detection are troublesome in the existing salt crystallization process experiment, and the detection data and the actual deviation are large because the sampling is not timely.

Description

Technical Field

[0001] The utility model belongs to the technical field of salt production detection equipment, and particularly relates to an experimental device for sodium chloride crystallization with controllable online particle size. Background Art

[0002] Crystal particle size and particle size distribution are one of the most important indicators of crystal products, which mainly affect solid-liquid separation in the crystallization production process, the drying process of products, the purity of products, the fluidity and appearance of products, the consolidation of products, specific requirements for specific products (such as uniform particle size, small and dispersed), and the yield of products. Therefore, controlling the crystal product particle size and particle size distribution during the crystallization process is one of the primary tasks in crystallization process control. In the industrial production of sodium chloride, the size and particle size distribution of crystal products have an important impact on the production process and product quality. Sodium chloride crystals have the characteristic of being easy to deliquesce. Since the current production of salt grains is relatively fine and unevenly distributed, when placed at room temperature without adding anti-caking agents, it is extremely easy to absorb moisture. Under the action of water molecules on the surface of salt grains, the salt grains continuously overlap and crosslink with each other, resulting in caking phenomena, which brings great inconvenience to the storage, transportation and application of salt. Therefore, it is necessary to add anti-caking agents to salt to alleviate caking, but the addition of anti-caking agents will introduce impurities, affecting the purity, safety and health of salt.

[0003] Therefore, in view of the above situation, the development of green and healthy salt products with high purity, low impurity content, bright color, high crystallinity and uniform particles has attracted much attention. Among them, many scholars have improved the sodium chloride production process, mainly focusing on the regulation of particle size and crystal habit during the sodium chloride crystallization process and the inhibition of sodium chloride caking. Relevant research shows that as the particle size of salt increases and the particle size distribution becomes more uniform, especially when the particle size is controlled within the range of 0.5 - 0.85 μm, the caking phenomenon of salt is significantly reduced, with better anti-caking properties and increased fluidity.

[0004] Currently, for the control of salt particle size, generally, by controlling a single variable, such as additives, crystallization temperature, evaporation rate, stirring speed, pH, etc., to adjust the salt crystal particle size. However, when controlling the single variable parameter in a gradient manner, it is necessary to first take out the materials in the crystallization mother liquor container under a certain parameter, then dry them, and then conduct particle size analysis. Therefore, it is necessary to frequently repeat the operations of taking out, drying and particle size analysis of the above materials. The experimental process is rather troublesome and cumbersome, with low experimental efficiency. Moreover, due to the untimely sampling, the particle size detection data will deviate from the actual situation. Summary of the Utility Model

[0005] In view of the above problems, the purpose of the present utility model is to provide an experimental device for sodium chloride crystallization with controllable particle size online, so as to solve the problems that in the existing salt crystallization process experiments, it is rather troublesome to frequently sample and detect the particle size, and due to the untimely sampling, the detected data is prone to have a large deviation from the actual situation.

[0006] The present utility model is realized through the following technical solutions.

[0007] An experimental device for sodium chloride crystallization with controllable particle size online includes a crystallization mother liquor tank, a feed pipe arranged at the top of the crystallization mother liquor tank, a heating interlayer arranged at the bottom of the crystallization mother liquor tank for heating the brine in the crystallization mother liquor tank. It is characterized in that it further includes a pH meter for monitoring the pH of the brine in the crystallization mother liquor tank, a thermometer for monitoring the temperature of the brine in the crystallization mother liquor tank, a stirring device for stirring the brine in the crystallization mother liquor tank, a vacuum extraction pipe arranged at the top of the crystallization mother liquor tank and communicated with the crystallization mother liquor tank, and an online particle size monitoring component; the online particle size monitoring component includes a particle size monitoring probe arranged at the bottom inside the crystallization mother liquor tank for monitoring the crystallization particle size distribution data, and a host computer connected to the particle size monitoring probe.

[0008] Preferably, the stirring device includes a driving motor arranged at the top of the crystallization mother liquor tank, a rotating shaft with one end connected to the power output end of the driving motor and the other end extending into the crystallization mother liquor tank, and a stirring paddle arranged at the bottom end of the rotating shaft.

[0009] Preferably, the stirring paddle is a double-layer stirring paddle, which includes a leaf-type stirring paddle and an anchor-type stirring paddle arranged on the rotating shaft from top to bottom in sequence.

[0010] Preferably, a valve is arranged on the vacuum extraction pipe, and the vacuum extraction pipe is connected to an external vacuum pump.

[0011] Preferably, an overflow pipe is arranged at the top of the side wall of the crystallization mother liquor tank, and a valve 801 is arranged on the overflow pipe 101.

[0012] Preferably, a water inlet pipe and a water outlet pipe are respectively communicated on both sides of the heating interlayer for introducing water at different temperatures into the heating interlayer to water-bath heat the brine in the crystallization mother liquor tank.

[0013] Compared with the prior art, the beneficial effects of the present utility model are: the structure of the present utility model is simple and the operation is convenient. When using the present utility model for salt crystallization process experiments, not only can the temperature, pH, vacuum degree and stirring speed during brine crystallization be conveniently controlled or monitored, but also the particle size of the crystallization can be monitored in real time. It not only solves the problems that in the existing salt crystallization process experiments, it is rather troublesome to frequently sample and detect the particle size, and due to the untimely sampling, the detected data is prone to have a large deviation from the actual situation, but also can greatly improve the experimental efficiency. Description of the Drawings

[0014] Figure 1 is a schematic structural diagram of the present utility model;

[0015] Figure 2 is a crystal size distribution diagram monitored in real time in Example 2;

[0016] Figure 3 is a crystal morphology diagram of the salt prepared in Example 2;

[0017] Figure 4 is a crystal size distribution diagram monitored in real time in Example 3;

[0018] Figure 5 is a crystal morphology diagram of the salt prepared in Example 3;

[0019] The meanings of the various identifications in the above figures are as follows: crystallization mother liquor tank 1, overflow pipe 101, heating jacket 2, water inlet pipe 201, water outlet pipe 202, pH meter 3, thermometer 4, stirring device 5, drive motor 501, rotating shaft 502, stirring paddle 503, blade-type stirring paddle 5031, anchor-type stirring paddle 5032, on-line particle size monitoring component 6, particle size monitoring probe 601, mainframe 602, feed pipe 7, valve 701, vacuum extraction pipe 8, valve 801. Specific embodiments

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0021] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0022] Example 1

[0023] An experimental device for sodium chloride crystallization with on-line controllable particle size, please refer to Figure 1, including a crystallization mother liquor tank 1, a feed pipe 7 arranged at the top of the crystallization mother liquor tank 1, a heating jacket 2 arranged at the bottom of the crystallization mother liquor tank 1 for heating the brine in the crystallization mother liquor tank 1, a pH meter 3 for monitoring the pH of the brine in the crystallization mother liquor tank 1, a thermometer 4 for monitoring the temperature of the brine in the crystallization mother liquor tank 1, a stirring device 5 for stirring the brine in the crystallization mother liquor tank 1, a vacuum extraction pipe 8 arranged at the top of the crystallization mother liquor tank 1 and communicating with the crystallization mother liquor tank 1, and an on-line particle size monitoring assembly 6; the on-line particle size monitoring assembly 6 includes a particle size monitoring probe 601 arranged at the inner bottom of the crystallization mother liquor tank 1 for monitoring the crystallization particle size distribution data, and a host 602 connected to the particle size monitoring probe 601;

[0024] In the above structure, in order to facilitate the cleaning inside the crystallization mother liquor tank 1, the bottom of the crystallization mother liquor tank 1 is hemispherical, and the volume of the crystallization mother liquor tank 1 is set to 2000 mL; the addition of mother liquor and related additives can be facilitated through the feed pipe 7; the stirring device 5 includes a driving motor 501 arranged at the top of the crystallization mother liquor tank 1, a rotating shaft 502 with one end connected to the power output end of the driving motor 501 and the other end extending into the crystallization mother liquor tank 1, and a stirring paddle 503 arranged at the bottom end of the rotating shaft 502; and, the stirring paddle 503 is a double-layer stirring paddle, and the stirring paddle 503 successively includes a leaf-type stirring paddle 503 and an anchor-type stirring paddle 504 arranged on the rotating shaft 502 from top to bottom; the brine in the crystallization mother liquor tank 1 can be stirred through the stirring device 5 to make the brine evenly heated and make the brine and other additives evenly mixed; an overflow pipe 101 is arranged at the top of the side wall of the crystallization mother liquor tank 1, and the highest liquid level of the crystallization mother liquor tank 1 can be controlled through the overflow pipe 101. When the brine level in the crystallization mother liquor tank 1 exceeds the position of the overflow pipe 101, the brine will automatically overflow; water inlet pipes 201 and outlet pipes 202 are respectively communicated on both sides of the heating jacket 2, so that water at different temperatures can be introduced into the heating jacket 2 to water-bath heat the brine in the crystallization mother liquor tank 1; the pH meter 3 and the thermometer 4 are selected as corrosion-resistant and high-temperature-resistant detection elements commonly used in the chemical industry, and the pH and temperature of the brine in the crystallization mother liquor tank 1 can be monitored in real time through the pH meter 3 and the thermometer 4; valves 801 are arranged on the overflow pipe 101, the feed pipe 7 and the vacuum extraction pipe 8, and the vacuum extraction pipe 8 is connected to an external vacuum pump, so that the vacuum degree in the crystallization mother liquor tank 1 can be adjusted by reasonably controlling the opening and closing states of each valve 801 and the working parameters of the vacuum pump; the particle size monitoring probe 601 is composed of a communication port, a light source port, a micro lens, a micro CCD camera and a light source. The particle size monitoring probe 601 can transmit the detected crystallization particle size distribution data to the host 602 in real time to realize the implementation monitoring of the crystallization particle size in the crystallization mother liquor tank 1;

[0025] When conducting experiments on the salt crystallization process using the present utility model, refined brine for salt production and related additives are added into the crystallization mother liquor tank 1 through the feed pipe 7. After setting the experimental parameters, relevant parameters such as pH, temperature, stirring speed, and vacuum degree are adjusted and monitored through the stirring device, pH meter, thermometer, and vacuum extraction pipe, so that the brine in the crystallization mother liquor tank 1 crystallizes under supersaturated conditions. The online particle size monitoring component 6 can be used to monitor the crystallization particle size in real time. Based on the above, the implementation of the present utility model can be completed.

[0026] Example 2

[0027] Using the experimental device of Example 1, 1500 ml of refined brine for salt production (provided by Xiangheng Salt Chemical) was added to a 2000 ml crystallization mother liquor container. The temperature was set at 65 °C, the stirring speed was 300 r / min, the vacuum degree was controlled at -0.05 MPa, the pH of the brine was adjusted to 8, and the solution was crystallized under supersaturated conditions. The evaporation amount was controlled at 500 ml, and the online particle size monitoring component was used to monitor the crystallization particle size in real time. The results Figure 2 showed that the volume average particle size of the crystals was about 116 μm; then the mother liquor was drawn out for filtration and drying, and the crystal morphology obtained was as Figure 3 shown.

[0028] Example 3

[0029] Using the experimental device of Example 1, 1500 ml of refined brine for salt production (provided by Xiangheng Salt Chemical) was added to a 2000 ml crystallization mother liquor container. The temperature was set at 65 °C, the stirring speed was 300 r / min, the vacuum degree was controlled at -0.05 MPa, the pH of the brine was adjusted to 11, and the solution was crystallized under supersaturated conditions. The evaporation amount was controlled at 500 ml, and the online particle size monitoring component was used to monitor the crystallization particle size in real time. The results Figure 4 showed that the volume average particle size of the crystals was about 213 μm; then the mother liquor was drawn out for filtration and drying, and the crystal morphology obtained was as Figure 5 shown.

[0030] Based on the data of Example 3 and Example 4, it can be seen that when the temperature, stirring speed, and vacuum degree are the same, as the pH increases, the volume average particle size of the crystals increases from 116 μm to 213 μm, and the fine crystals basically disappear. Similarly, during specific implementation, the present utility model device can also be used to optimize other influencing factors of the salt crystallization process, which will not be elaborated and exemplified here.

Claims

1. An online sodium chloride crystallization experimental device with controllable particle size, comprising a crystallization mother liquid tank (1), a feed pipe (7) arranged at the top of the crystallization mother liquid tank (1), and a heating interlayer (2) arranged at the bottom of the crystallization mother liquid tank (1) for heating brine in the crystallization mother liquid tank (1), characterized in that: The invention also comprises a pH meter (3) for monitoring the pH value of brine in the crystallization mother liquid tank (1), a thermometer (4) for monitoring the temperature of brine in the crystallization mother liquid tank (1), a stirring device (5) for stirring the brine in the crystallization mother liquid tank (1), a vacuum tube (8) arranged at the top of the crystallization mother liquid tank (1) and connected to the crystallization mother liquid tank (1), and an online particle size monitoring component (6); the online particle size monitoring component (6) comprises a particle size monitoring probe (601) arranged at the bottom of the crystallization mother liquid tank (1) and used to monitor crystal particle size distribution data, and a host (602) connected to the particle size monitoring probe (601).

2. A sodium chloride crystallization experimental device with online controllable particle size as claimed in claim 1, characterized in that, The stirring device (5) comprises a driving motor (501) arranged at the top of the crystallization mother liquid tank (1), a rotating shaft (502) having one end connected to the power output end of the driving motor (501) and the other end extending to the crystallization mother liquid tank (1), and a stirring paddle (503) arranged at the bottom of the rotating shaft (502).

3. A sodium chloride crystallization experimental device with online controllable particle size as claimed in claim 2, characterized in that, The stirring paddle (503) is a double-layer stirring paddle, which includes a blade-type stirring paddle (5031) and an anchor-type stirring paddle (5032) which are sequentially arranged on the rotating shaft (502) from top to bottom.

4. A sodium chloride crystallization experimental device with online controllable particle size as claimed in claim 1, characterized in that, Valves (801) are provided on the vacuum pipe (8) and the feed pipe (7), and the vacuum pipe (8) is connected to an external vacuum pump.

5. A sodium chloride crystallization experimental device with online controllable particle size as claimed in claim 1, characterized in that, An overflow pipe (101) is provided at the top of the side wall of the crystallization mother liquid tank (1), and a valve (801) is provided on the overflow pipe (101).

6. A sodium chloride crystallization experimental device with online controllable particle size as claimed in claim 1, characterized in that, The two sides of the heating interlayer (2) are respectively connected with a water inlet pipe (201) and a water outlet pipe (202), which are used to introduce water of different temperatures into the heating interlayer (2) to water-bath heat the brine in the crystallization mother liquid tank (1).

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