On-line elutriation device of non-purified calcium type brine heat pump salt-making evaporation tank

Abstract

The utility model discloses an on-line elutriation device of a non-purified calcium type brine heat pump salt-making evaporation tank, which belongs to the technical field of salt-making production and is characterized in that an upper elutriation pipe is horizontally arranged on a barrel close to a lower cone end in a penetrating manner, and an elutriation hole group for elutriation water to flow out is arranged on the upper elutriation pipe positioned in the barrel; a middle elutriation pipe is horizontally arranged in the middle of the lower cone in a penetrating manner, and a liquid outlet for elutriation water to flow out is formed in the end part, extending into the cone, of the middle elutriation pipe; a lower elutriation pipe is horizontally arranged on the lower cone close to the opening end of the accident discharge pipe, and the lower elutriation pipe is communicated with the inner cavity of the lower cone; a salt discharge pipe is horizontally arranged on the barrel body opposite to the mounting side of the upper elutriation pipe in a penetrating manner; and a liquid inlet for salt slurry to enter the salt discharge pipe is formed in the end part of the salt discharge pipe extending into the barrel body. According to the utility model, the descending feed liquid in the salt leg of the evaporation tank is efficiently elutriated, the content of impurities and small-particle sodium chloride crystals in discharged salt slurry is reduced, and the temperature of the discharged salt slurry can be reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of salt production, in particular to an online washing device for a non-purified calcium brine heat pump salt production evaporation tank. Background Art

[0002] In the well salt production industry, for calcium sulfate rock salt mines, the raw brine mined contains, in addition to sodium chloride, small amounts of impurity ions such as calcium ions, magnesium ions, and sulfate. Currently, salt production companies that use a non-purified calcium sulfate brine heat pump salt production process use unpurified raw brine pumped into the heat pump salt production system. As the raw brine evaporates and crystallizes to form sodium chloride (salt) in the evaporation tank, the impurity ions such as calcium, magnesium, and sulfate contained in it will precipitate as calcium sulfate, magnesium hydroxide, and other insoluble matter during the evaporation and concentration process of the feed liquid.

[0003] The evaporator consists of a heating chamber, evaporation chamber, brine legs, a circulation pump, and the interconnecting circulation pipes. Unpurified raw brine enters the evaporator after preheating. Driven by the circulation pump, the brine flows from the pump outlet through the circulation pipe, heating chamber, circulation pipe, evaporation chamber, circulation pipe, paste removal device, circulation pipe, and finally back to the circulation pump inlet, forming a continuous flow system. As the brine flows into the heating chamber, the low-temperature raw brine in the tube side and the high-temperature steam in the shell side heat up through heat conduction from the tube walls, continuously raising the temperature to form a high-temperature liquid. During this continuous flow, heat exchange, and temperature increase, the liquid continuously evaporates, concentrates, and crystallizes, producing a large amount of sodium chloride crystals and a small amount of impurities, primarily calcium sulfate. Due to the different physical and fluid dynamic characteristics of the crystallized materials, the evaporator is designed with a brine leg at the bottom of the evaporation chamber to collect and discharge the sodium chloride crystals. A paste removal device is located between the upper and lower circulation pipes to remove impurities such as calcium sulfate.

[0004] Lack of effective washing of the downstream liquid in the salt legs of the evaporator results in an increase in impurities and small sodium chloride crystals in the discharged salt slurry, and the slurry temperature fails to be effectively reduced. This high slurry temperature shortens the centrifuge's service life, while the high temperature of the discharged salt slurry leads to excessive heat loss in the system, resulting in various adverse effects. Summary of the Invention

[0005] In response to the problems existing in the prior art, the utility model provides an online washing device for a non-purified calcium brine heat pump salt-making evaporation tank, which can wash calcium sulfate, small-particle sodium chloride and other impurities formed in the evaporation and crystallization process of refined salt online, ensure the quality of the discharged salt slurry, achieve efficient washing of the downstream liquid in the salt leg of the evaporation tank, and reduce the content of impurities and small-particle sodium chloride crystals in the discharged salt slurry; and can reduce the material temperature of the discharged salt slurry, thereby achieving the purpose of reducing the energy consumption of the salt-making device and extending the service life of the centrifuge and belt conveyor.

[0006] The utility model is realized as follows: an online elution device for a non-purified calcium brine heat pump salt evaporation tank, wherein a salt leg is provided at the bottom of the evaporation tank, the salt leg comprising a cylinder and a lower cone, the large diameter end of the lower cone being connected to the lower end of the cylinder, the small diameter end of the lower cone being provided with an emergency discharge nozzle, an upper elution pipe being provided horizontally through the cylinder near the lower cone end, the end of the upper elution pipe extending into the cylinder being a closed end, and the upper elution pipe located in the cylinder being provided with an elution hole group for outflow of elution water;

[0007] A middle washing pipe is horizontally provided at the middle position of the lower cone, and a liquid outlet for washing water to flow out is provided at the end of the middle washing pipe extending into the cone;

[0008] A lower washing pipe is horizontally arranged on the lower cone near the end of the emergency discharge pipe, and the lower washing pipe is connected to the inner cavity of the lower cone;

[0009] A salt discharge pipe is horizontally provided on the cylinder body on the side where the upper washing pipe is installed. The salt discharge pipe is located below the upper washing pipe. The end of the salt discharge pipe extending into the cylinder body is provided with a liquid inlet for salt slurry to enter the salt discharge pipe.

[0010] Furthermore, the protruding ends of the upper washing pipe, the middle washing pipe and the lower washing pipe are all connected to the washing water pump through connecting pipes, and the connecting pipes are sequentially provided with a gate valve, a flow meter and a pneumatic valve along the washing water flow direction.

[0011] Furthermore, the washing hole group includes three rows of hole groups, one row of hole groups is located at the bottom of the upper washing tube, and the other two rows of hole groups are symmetrically arranged at 60° to the bottom hole group.

[0012] Furthermore, each row of hole groups includes a plurality of circular holes, and the plurality of circular holes are equidistantly arranged along the axial direction of the upper washing tube.

[0013] Furthermore, two upper washing pipes are provided, and the two upper washing pipes are symmetrically distributed along the center line of the cylinder.

[0014] Furthermore, two salt discharge pipes are provided, and the two salt discharge pipes are located on both sides of the horizontal center line of the cylinder cross section, and the installation axis of the salt discharge pipe is set at an angle of 30° to the horizontal center line of the cylinder cross section.

[0015] Furthermore, the upper elutriation pipe, the middle elutriation pipe and the lower elutriation pipe are located on the same side of the salt leg.

[0016] Furthermore, the opening directions of the liquid outlet and the liquid inlet are both inclined downward at 45 degrees.

[0017] The utility model has the following advantages and technical effects: due to the adoption of the above technical scheme, the mixed brine is pumped into the salt leg by using the washing water pump through the upper, middle and lower three-stage washing pipes, the salt discharge pipe and the valve, the flow meter and other supporting facilities, the downstream feed liquid is countercurrently washed in the salt leg, and the large-particle sodium chloride and the calcium sulfate with low density and the small-particle sodium chloride crystals in the feed liquid are automatically separated online in continuous production; after the separation, the large-particle sodium chloride is collected into salt slurry and discharged to the centrifuge through the salt discharge pipe to become the salt product; the calcium sulfate after separation is returned to the evaporation tank and then discharged from the system through the paste discharge device; the small-particle sodium chloride crystals after separation are returned to the evaporation tank to continue to grow into large-particle sodium chloride crystals and are discharged to the centrifuge in the form of salt slurry to become the salt product.

[0018] This device not only effectively washes calcium sulfate, small particles of sodium chloride, and other impurities formed during the evaporation and crystallization of refined salt online, ensuring the quality of the discharged salt slurry, but also efficiently washes the downstream liquid in the salt legs of the evaporator, reducing the content of impurities and small particles of sodium chloride crystals in the discharged salt slurry. It also lowers the temperature of the discharged salt slurry, thereby reducing energy consumption in the salt production unit and extending the service life of the centrifuge and belt conveyor. This online elutriation device boasts a simple structure, high elutriation efficiency, and a high degree of automation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a front view of the overall structure provided by an embodiment of the utility model;

[0020] Figure 2 This is a top view of the overall structure provided by an embodiment of the utility model;

[0021] Figure 3 It is a schematic diagram of the structure of the upper washing tube provided in an embodiment of the utility model.

[0022] In the figure: 1, salt leg; 1-1, cylinder; 1-2, lower cone; 1-3, emergency discharge pipe outlet; 2, upper washing pipe; 2-1, washing hole group; 3, middle washing pipe; 3-1, liquid outlet; 4, lower washing pipe; 5, salt discharge pipe; 5-1, liquid inlet. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] It should be noted that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0025] like Figures 1 to 3 As shown, the present application provides an online washing device for a non-purified calcium brine heat pump salt evaporation tank, wherein a salt leg is connected to the bottom of the evaporation tank, and the salt leg includes a cylinder and a lower cone, the large diameter end of the lower cone is connected to the lower end of the cylinder, and the small diameter end of the lower cone is provided with an emergency discharge pipe mouth.

[0026] An upper elution tube extends horizontally through the cylinder near the lower conical end. The end of the upper elution tube extending into the cylinder is closed. Specifically, the closed end is sealed with a 145 mm φ, δ = 8 mm circular plate, placed within a 159 mm φ x 6 mm support tube and welded to the inner wall of the opposite salt leg cylinder. The upper elution tube within the cylinder is provided with an elution hole group for the outflow of elution water. The elution hole group is located in the middle area of ​​the upper elution tube. Preferably, the elution hole group includes three rows of holes, one of which is located at the bottom of the upper elution tube, and the other two rows of holes are arranged symmetrically at 60° to the bottom hole group. Each row of holes includes multiple circular holes, which are equidistantly spaced along the axial direction of the upper elution tube. Specifically, there are 86 circular holes, each with a diameter of 10 mm. Preferably, there are two upper elution tubes, symmetrically distributed along the centerline of the cylinder. Specifically, the two upper elutriation tubes are located 550 mm from the centerline of the cylinder. Each upper elutriation tube measures φ133 mm x 6 mm x 2456 mm and is made of S31603. The two upper elutriation tubes are inserted horizontally into the salt legs, oriented at a 150-degree angle relative to the direction of insertion of the two salt drain pipes. Vertically, the upper elutriation tubes are positioned above the salt drain pipes, with a vertical distance of 1200 mm between them.

[0027] A salt discharge pipe is provided horizontally through the cylinder on the side where the upper washing pipe is installed. The salt discharge pipe is located below the upper washing pipe. Specifically, the vertical distance between the salt discharge pipe and the upper washing pipe is 1200 mm. The specifications of the salt discharge pipe are all φ133 mm × 6 mm × 1222 mm, and the material of the salt discharge pipe is S31603. The end of the salt discharge pipe extending into the cylinder is provided with a liquid inlet for the salt slurry to enter the salt discharge pipe. Preferably, the opening direction of the liquid inlet is inclined downward at 45°. This structure can effectively reduce the risk of clogging of the salt discharge pipe inlet caused by the descending liquid under special working conditions. Preferably, there are two salt discharge pipes, and the two salt discharge pipes are located on both sides of the horizontal center line of the cylinder cross section, and the installation axis of the salt discharge pipe is set at an angle of 30° to the horizontal center line of the cylinder cross section.

[0028] A central elutriation pipe runs horizontally through the middle of the lower cone. Specifically, it's located below the salt drain pipe, with a vertical distance of 1100 mm between them. Its dimensions are φ133 mm x 6 mm x 1085.5 mm, and it's made of S31603. An outlet for the elutriation water is located at the end of the pipe, extending into the cone. Preferably, the outlet is angled downward at a 45° angle, ensuring that the elutriation water enters the salt leg obliquely downward. This effectively reduces the risk of clogging the inlet of the central elutriation pipe caused by descending liquid during special operating conditions. The central elutriation pipe is inserted horizontally into the salt leg, specifically opposite the direction the two salt drain pipes are inserted into the leg. It's arranged at an angle of ±150° horizontally to the two drain pipes. Vertically, it's located below the drain pipe, with a vertical distance of 1100 mm between them.

[0029] A lower elutriation pipe is installed horizontally on the lower cone near the emergency discharge outlet. It communicates with the interior of the lower cone. Specifically, the lower elutriation pipe is 220 mm vertically from the bottom emergency discharge flange. It has a nominal diameter of 150 mm, a length of 300 mm, and is made of S31603. The lower elutriation pipe is connected horizontally to the salt leg, oriented horizontally at a 90-degree angle relative to the direction in which the middle elutriation pipe inserts into the salt leg. Vertically, the lower elutriation pipe is located below the middle elutriation pipe, with a vertical distance of 1485 mm.

[0030] Furthermore, the protruding ends of the upper, middle and lower washing pipes are all connected to the washing water pump through connecting pipes, and a gate valve, a flow meter and a pneumatic valve are sequentially arranged on the connecting pipes along the direction of the washing water flow. The gate valve, the flow meter and the pneumatic valve are all made of stainless steel, which can effectively resist the corrosive effects of the sodium chloride slurry on them. Especially for slurries with higher concentrations, when environmental conditions change, such as changes in temperature and pressure, disturbances in the flow rate and direction of the downstream slurry and the countercurrent washing brine, and the scouring of the discharged salt slurry, more obvious corrosion risks will be caused. Therefore, the use of stainless steel can significantly improve the device's resistance to the corrosive effects of the sodium chloride slurry on it.

[0031] Furthermore, the upper elutriation pipe, the middle elutriation pipe and the lower elutriation pipe are located on the same side of the salt leg.

[0032] The washing water is a supersaturated mixed brine from the mixed brine barrel, which is composed of saturated raw brine preheated by the low-temperature plate heat exchanger and the centrifuge sluice mixed with small particles of sodium chloride crystals. The temperature of the mixed brine can be controlled at 45-50°C by adjusting the operating mode of the low-temperature plate heat exchanger, so as to effectively cool the high-temperature downstream feed liquid and reduce the temperature of the discharged salt slurry to 50-55°C. The small amount of small particles of sodium chloride crystals mixed in the mixed brine keeps the mixed brine in a supersaturated state, which not only prevents the mixed brine from dissolving the existing sodium chloride crystals in the feed liquid, but also allows the small particles of sodium chloride crystals in the mixed brine entering the salt leg to continue to grow into large particles of sodium chloride crystals, thereby increasing salt production.

[0033] Working Principle: The mixed brine in the brine barrel, at a temperature of 45-50°C, is pumped by an elutriation pump to the following three branches of the online elutriation device for the spitting tank: the upper elutriation branch, the middle elutriation branch, and the lower elutriation branch. The elutriation water in the upper elutriation branch flows through the following path: elutriation pump → gate valve → flow meter → pneumatic valve → gate valve → upper elutriation pipe → salt leg.

[0034] The pneumatic valves and flowmeters in the upper elutriation branch control the flow rate of elutriation water entering the salt leg from the upper elutriation pipe at 75-85 cubic meters per hour. Two upper elutriation pipes are symmetrically inserted in parallel in the middle of the salt leg's cross section. Three rows of 258 10 mm circular holes are located at the bottom of each elutriation pipe in the middle region. Elutriation water flows from the bottom of the upper elutriation pipe in a 60-degree fan pattern, occupying the cross section of the salt leg and flowing countercurrently with the descending feed liquid. The elutriation water returns the less dense calcium sulfate impurities and smaller sodium chloride crystals in the feed liquid to the evaporation tank to continue the production cycle. Large sodium chloride crystals in the feed liquid, due to their higher density, are driven by the downward force of the elutriation water and are subsequently discharged into the salt discharge pipe. The salt slurry pump then delivers them to the centrifuge for dehydration and production. The upper elutriation branch, through the coordinated cooperation of pneumatic valves and flowmeters, can regulate the elutriation water flow rate and reverse flow velocity. By controlling the elutriation water flow rate and reverse flow velocity, the downstream slurry can be precisely screened. The greater the elutriation water flow rate (i.e., the faster the reverse flow velocity), the more thoroughly the calcium sulfate impurities in the slurry are washed out. This results in slightly larger sodium chloride crystals returned to the evaporation tank, while the sodium chloride crystals in the salt slurry continuously discharged through the salt discharge pipe will also be larger, but the number of sodium chloride crystals will be reduced, thus affecting the yield of refined salt. Therefore, through the scientific and rational coordination of pneumatic valves and flowmeters, the upper elutriation branch is designed to achieve an optimal balance between elutriation quality and refined salt yield to guide production operations. Furthermore, the 10mm φ circular hole in the upper elution tube is located at the bottom of the tube, with the outlet facing downward, for two reasons: First, to reduce the risk of impurities or sodium chloride crystals blocking the circular hole caused by the downward flow of the slurry during abnormal equipment operation (such as a sudden power outage or equipment failure). Second, the elution water first flows downward through the circular hole and then flows back up. This upward and downward movement increases the stagnation time of the elution water on the cross-section of the salt leg, which is equivalent to extending the elution water's distribution period on the cross-section of the salt leg. This allows the counterflowing elution water to occupy a larger area on the cross-section of the salt leg and distribute more evenly, thus more thoroughly eluting the downward slurry.

[0035] The path through which the washing water in the middle washing branch flows is:

[0036] Washing water pump → gate valve → flow meter → pneumatic valve → gate valve → middle washing pipe → salt leg.

[0037] The pneumatic valve and flowmeter in the middle elution branch control the flow rate of elution water entering the salt leg from the middle elution pipe at 50-60 cubic meters per hour. The middle elution pipe is inserted horizontally into the lower portion of the salt leg, with its end near the center of the lower conical section of the salt leg. Vertically, it is located 1,100 mm below the salt discharge pipe. After entering the salt leg from the end of the middle elution pipe, the elution water, under the pressure of the elution pump, flows upstream from the center of the lower cone of the salt leg. Since the salt discharge pipe is the only channel for the salt slurry to be discharged from the lower salt leg, the pressure there naturally reaches the lowest point in the center of the lower cone. Under pressure, the slurry flowing down the salt leg and the elution water flowing up the middle elution pipe flow from the periphery toward the low-pressure area at the salt discharge pipe inlet. When the feed liquid (including washing water) flows rapidly from the periphery to the salt discharge pipe, the closer it is to the center of the fluid movement direction, the faster the flow rate of the feed liquid, and the farther it is from the center of the fluid movement direction, the slower the flow rate of the feed liquid. This causes the large-particle sodium chloride crystals with higher density in the feed liquid to flow rapidly to the salt discharge pipe along the main direction of the feed liquid movement, while those impurities such as calcium sulfate and small-particle sodium chloride crystals with lower density that have not been thoroughly washed out by the upper washing will move to the edge of the main movement area of ​​the feed liquid and spread around the central area of ​​the cone under the salt leg. Driven by the middle washing water, they will go upstream against the current and float to the range of the upper washing. After the upper washing is completed, they will be sent to the circulation system of the evaporation tank. During the circulation flow, the paste discharge device will discharge impurities such as calcium sulfate from the system, and the small-particle sodium chloride crystals will continue to be heated, thereby achieving the purpose of continued growth of sodium chloride crystals during operation. The washing branch in this invention can adjust the flow rate and reverse flow rate of the washing water through the linkage of the pneumatic valve and the flow meter, and by controlling the flow rate and reverse flow rate of the washing water, it can realize accurate distinction of different components in the slurry. The greater the flow rate of the washing water, that is, the faster the reverse flow rate of the washing water, the more thoroughly the calcium sulfate impurities and small-particle sodium chloride crystals in the slurry will be washed. However, if the flow rate of the washing water is too large, that is, the reverse flow rate of the washing water is too fast, the reverse-flow washing water will establish a short-circuit channel with the salt discharge pipe at a low pressure, thereby squeezing out the flow channel space for large-particle sodium chloride crystals in the slurry, that is, the salt slurry, reducing the efficiency of the salt discharge pipe and affecting the output of refined salt. Therefore, the middle elution branch, through the scientific and rational coordination of pneumatic valves and flow meters, is designed to have a reasonable elution water volume. This ensures that the elution water returns a sufficient amount of calcium sulfate impurities and small sodium chloride crystals in the slurry to the area controlled by the upper elution pipe, and also prevents the elution water from short-circuiting with the salt discharge pipe. Furthermore, at the end of the middle elution pipe, a 45° downward horseshoe opening is left in the direction of the elution water outlet. The elution water outlet is directed downward for two reasons: First, in the event of abnormal equipment operation (such as sudden power outages or equipment failures), the risk of impurities or sodium chloride crystals blocking the circular hole caused by the downward flow of the slurry is reduced.Secondly, the elution water flows back in the process of diffusing to the periphery of the outlet, which increases the stagnation time of the elution water on the cross section of the salt leg and prolongs the distribution period of the elution water on the cross section of the salt leg, ensuring that the countercurrent elution water occupies a larger area and is distributed more evenly on the cross section of the salt leg, and washes the residual calcium sulfate impurities and small-particle sodium chloride crystals in the slurry more fully, and reduces the risk of the elution water flowing directly into the salt discharge pipe and causing a short circuit in the slurry flow.

[0038] The path of the washing water in the lower washing branch flows through:

[0039] Washing water pump → gate valve → flow meter → pneumatic valve → gate valve → lower washing pipe → salt leg

[0040] The pneumatic valve and flowmeter in the lower elutriation branch control the flow rate of elutriation water entering the salt leg from the lower elutriation pipe at 5 to 15 cubic meters per hour. The lower elutriation pipe is connected horizontally to the bottom of the salt leg, oriented horizontally at a 90-degree angle to the direction in which the middle elutriation pipe enters the salt leg. Vertically, the lower elutriation pipe is located below the middle elutriation pipe, with a vertical distance of 1485 mm. A downward-facing emergency discharge port is provided at the bottom of the salt leg. During normal operation, the emergency port is in a closed state, thus forming a relatively static flow blind zone at the bottom of the salt leg. As the liquid in the salt leg descends, despite undergoing upper and middle level washing, a small amount of calcium sulfate impurities and small-particle sodium chloride crystals will inevitably fall into the flow blind zone at the bottom of the salt leg. Similarly, although most of the large-particle sodium chloride crystals entrained in the liquid descending from the salt leg are discharged from the salt discharge pipe in the form of salt slurry, a very small number of large-particle sodium chloride crystals will still enter the flow blind zone of the salt leg. As time goes by, the above materials continue to accumulate in the flow blind zone. If the liquid in this area does not flow for a long time, these materials will gradually gather here and become compacted into one, making it a dead zone. To prevent the occurrence of the above unexpected phenomena, after the washing water enters the salt leg from the lower washing pipe, the slurry at the bottom of the salt leg is always in a flowing state. At the same time, the washing water injected into the salt leg is used to return the calcium sulfate impurities and sodium chloride crystals that fall to the bottom of the salt leg to the area controlled by the middle washing pipe, and the middle washing branch carries out corresponding classification and screening. This lower washing branch can adjust the flow rate and upstream flow rate of the washing water through the linkage of the pneumatic valve and the flow meter, and by controlling the flow rate and upstream flow rate of the washing water, it can achieve accurate distinction of different components in the slurry. The greater the flow rate of the washing water, that is, the faster the upstream flow rate of the washing water, the more thoroughly the calcium sulfate impurities and small-particle sodium chloride crystals in the slurry will be washed. However, if the flow rate of the washing water is too large, that is, the upstream flow rate of the washing water is too fast, the upstream washing water will affect the washing effect of the middle washing and reduce the washing efficiency of the middle washing pipe. Therefore, the lower washing branch is designed with a suitable washing water volume through the scientific and reasonable coordination of the pneumatic valve and the flow meter, which not only ensures that the slurry at the bottom of the salt leg is always in a flowing state, but also enables the washing water to return the calcium sulfate impurities and sodium chloride crystals remaining in the upper and middle washings in the slurry to the area controlled by the middle washing pipe, and avoids the negative impact of the lower washing water on the washing efficiency of the middle washing pipe.

[0041] Due to the adoption of the above technical solution, the mixed brine is pumped into the salt leg by means of an elutriation water pump through the upper, middle and lower three-stage elutriation pipes, salt discharge pipes and supporting facilities such as valves and flow meters. The downstream feed liquid is countercurrently washed in the salt leg, and the large-particle sodium chloride in the feed liquid is automatically separated online from the calcium sulfate with low density and the small-particle sodium chloride crystals in the continuous production. After separation, the large-particle sodium chloride is collected into salt slurry and discharged to the centrifuge through the salt discharge pipe to become the salt product. After separation, the calcium sulfate is returned to the evaporation tank and then discharged from the system through the paste discharge device. The separated small-particle sodium chloride crystals are returned to the evaporation tank to continue to grow into large-particle sodium chloride crystals and are discharged to the centrifuge in the form of salt slurry to become the salt product.

[0042] This device not only effectively washes calcium sulfate, small particles of sodium chloride, and other impurities formed during the evaporation and crystallization of refined salt online, ensuring the quality of the discharged salt slurry, but also efficiently washes the downstream liquid in the salt legs of the evaporator, reducing the content of impurities and small particles of sodium chloride crystals in the discharged salt slurry. It also lowers the temperature of the discharged salt slurry, thereby reducing energy consumption in the salt production unit and extending the service life of the centrifuge and belt conveyor. This online elutriation device boasts a simple structure, high elutriation efficiency, and a high degree of automation.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An online washing device for a non-purified calcium brine heat pump salt evaporation tank, wherein the bottom of the evaporation tank is connected to a salt leg, the salt leg comprising a barrel and a lower cone, the large diameter end of the lower cone being connected to the lower end of the barrel, and the small diameter end of the lower cone being provided with an emergency discharge nozzle, characterized in that: An upper washing pipe is horizontally provided on the cylinder near the lower cone end, the end of the upper washing pipe extending into the cylinder is a closed end, and the upper washing pipe located in the cylinder is provided with a washing hole group for the outflow of washing water; A middle washing pipe is horizontally provided at the middle position of the lower cone, and a liquid outlet for washing water to flow out is provided at the end of the middle washing pipe extending into the cone; A lower elutriation pipe is horizontally arranged on the lower cone near the end of the accident discharge pipe. The lower elutriation pipe is connected to the inner cavity of the lower cone and is arranged at 90 degrees relative to the direction in which the middle elutriation pipe is inserted into the salt leg on the horizontal plane. A salt discharge pipe is horizontally provided on the cylinder on the side where the upper washing pipe is installed. The salt discharge pipe is located below the upper washing pipe, and the end of the salt discharge pipe extending into the cylinder is provided with a liquid inlet for the salt slurry to enter the salt discharge pipe; there are two salt discharge pipes, and the two salt discharge pipes are located on both sides of the horizontal center line of the cylinder cross section, and the installation axis of the salt discharge pipe is set at an angle of 30° to the horizontal center line of the cylinder cross section.

2. The online washing device for the non-purified calcium brine heat pump salt evaporation tank according to claim 1 is characterized in that: The extended ends of the upper washing pipe, the middle washing pipe and the lower washing pipe are all connected to the washing water pump through connecting pipelines, and a gate valve, a flow meter and a pneumatic valve are sequentially arranged along the washing water flow direction on the connecting pipeline.

3. The online washing device for the non-purified calcium brine heat pump salt evaporation tank according to claim 1 or 2, characterized in that: The washing hole group includes three rows of hole groups, one row of hole groups is located at the bottom of the upper washing tube, and the other two rows of hole groups are symmetrically arranged at 60 degrees to the bottom hole group.

4. The online washing device for the non-purified calcium brine heat pump salt evaporation tank according to claim 3 is characterized in that: Each row of hole groups includes a plurality of circular holes, and the plurality of circular holes are equidistantly arranged along the axial direction of the upper washing tube.

5. The online washing device for the non-purified calcium brine heat pump salt evaporation tank according to claim 1 is characterized in that: There are two upper washing pipes, which are symmetrically distributed along the center line of the cylinder.

6. The online washing device for the non-purified calcium brine heat pump salt evaporation tank according to claim 1 is characterized in that: The upper elutriation pipe, the middle elutriation pipe and the lower elutriation pipe are located on the same side of the salt leg.

7. The online washing device for the non-purified calcium brine heat pump salt evaporation tank according to claim 1 is characterized in that: The opening directions of the liquid outlet and the liquid inlet are both inclined downward at 45 degrees.

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