Lithium sulfate solution falling film evaporation apparatus

Abstract

The present application belongs to falling film evaporation technical field, especially to a kind of lithium sulfate solution falling film evaporation equipment, for concentrating lithium sulfate solution, including evaporation concentration component, steam collection component, evaporation concentration component is used to concentrate lithium sulfate solution, steam collection component is used to collect the water vapor released by evaporation concentration component and recycle.The structure at the bottom of the tank A for the inverted taper A of liquid discharge and the bottom of the tank B for the inverted taper B of water discharge in the present application can automatically control the height of the liquid level at the bottom of the tank A and the tank B, and make the liquid at the bottom of the tank A and the tank B always close to the inverted taper A and the inverted taper B, so that the hot steam does not leak, ensuring that all the hot steam is effectively recycled, avoiding heat waste.

Description

Technical Field

[0001] This invention belongs to the field of falling film evaporation technology, and particularly relates to a falling film evaporation device for lithium sulfate solution. Background Technology

[0002] Lithium sulfate solution is an intermediate product in the production of lithium salts such as lithium carbonate, lithium hydroxide monohydrate, and lithium chloride using the sulfuric acid process. In the industrial production of lithium salts, the concentration of lithium sulfate solution used as a raw material for extracting lithium salts such as lithium carbonate, lithium hydroxide monohydrate, and lithium chloride is relatively low. In order to minimize the energy consumption of subsequent lithium salt production and improve the direct recovery rate of lithium salts, the concentration of lithium sulfate solution is increased by evaporation and concentration.

[0003] In the evaporation and concentration process of lithium sulfate solution, falling film evaporators with high evaporation intensity, high heat transfer coefficient, and low material consumption are generally selected, such as... Figure 12 As shown, the falling film evaporator consists of multiple relatively thick concentration tubes installed at the bottom of the upper chamber. The lithium sulfate solution flows down the inner wall of the concentration tube in the form of a liquid film. Outside the concentration tube is hot steam. Under the heating of the hot steam, the temperature of the tube wall rises, and the liquid film of lithium sulfate solution inside the concentration tube evaporates due to the heat, which increases the concentration of lithium sulfate solution. The steam is discharged downward from the gaps between the concentration tubes.

[0004] The following problems still exist in the use of falling film evaporators:

[0005] 1. Falling film evaporators use large-diameter concentration tubes to reduce costs, but their evaporation efficiency is low due to the small liquid film adhesion area. Figure 13 As shown, replacing the thicker concentrator tube with a thinner one will greatly increase the area of ​​liquid film adhesion, thereby improving evaporation efficiency. However, the internal liquid film will occupy the entire space inside the concentrator tube, preventing the water vapor evaporated from the lithium sulfate solution from being discharged from the bottom of the tube and affecting the flow of the liquid film on the inner wall of the concentrator tube. Therefore, the discharge of vapor evaporated from the lithium sulfate solution and the adhesion area of ​​the lithium sulfate solution in the falling film evaporator will be limited by the diameter of the concentrator tube.

[0006] 2. When lithium sulfate solution evaporates inside the concentration tube, crystals form on the inner wall of the tube, which can block the flow of lithium sulfate solution along the inner wall of the concentration tube. The crystals are located on the inner wall of the concentration tube and are difficult to clean.

[0007] 3. For example Figure 12 As shown, the liquid level in the upper chamber of the falling film evaporator affects the initial velocity of the lithium sulfate solution reaching the inner wall of the concentration tube, and thus affects the formation of the liquid film on the inner wall of the concentration tube. Currently, the liquid level in the upper chamber of the falling film evaporator is controlled by controlling the flow rate of the inlet pipe, but the falling film evaporator itself does not have a related liquid level control function, which makes the liquid level in the upper chamber of the falling film evaporator vary greatly, thus affecting the formation of the liquid film.

[0008] 4. When there is little or no concentrated lithium sulfate solution at the drain port of the falling film evaporator, the hot steam in the falling film evaporator will leak from the drain port and cannot be fully recovered and reused, resulting in heat waste.

[0009] This invention designs a falling film evaporation device for lithium sulfate solution to solve the above problems. Summary of the Invention

[0010] Therefore, it is necessary to address the problems existing in current falling film evaporators by providing a lithium sulfate solution falling film evaporation device. This invention employs a small-diameter evaporation tube, allowing steam to flow through the tube, effectively increasing the adhesion area of ​​the liquid film on the outside of the evaporation tube and significantly improving the evaporation and concentration efficiency. This ensures that the emission of steam generated during lithium sulfate solution concentration and the formation of the liquid film are not limited by the diameter of the evaporation tube. Consequently, the diameter of the evaporation tube can be minimized while ensuring effective passage of internal steam, maximizing the area for liquid film adhesion and evaporation, and improving the evaporation and concentration efficiency of the lithium sulfate solution. Because the evaporation tube in this invention has the lithium sulfate solution attached and concentrated on its outer wall, crystals generated during lithium sulfate concentration only adhere to the outside of the evaporation tube and do not block the tube, preventing the steam generated during the evaporation and concentration from being discharged or affecting the effective formation of the liquid film. Furthermore, the crystals formed on the outside of the evaporation tube are easier to clean. This invention achieves automatic liquid level control through the structures on inlet pipes A and B at the top of tank A, thereby ensuring that the lithium sulfate solution on baffle B always adheres to the evaporation tube in a liquid film state and flows downwards through the leakage hole or connecting block. The structures at the inverted conical outlet A at the bottom of tank A for liquid drainage and at the inverted conical outlet B at the bottom of tank B for water drainage prevent hot steam leakage, ensuring effective recovery and utilization of all hot steam and avoiding heat waste.

[0011] The above objectives are achieved through the following technical solutions:

[0012] A falling film evaporation apparatus for concentrating lithium sulfate solution includes:

[0013] An evaporation and concentration assembly is used to concentrate lithium sulfate solution. The assembly includes a tank A, which is fixed to the ground by legs. The upper inner wall of tank A has an inverted conical surface. A baffle A is positioned above the inverted conical surface, forming an annular gap between the baffle A and the inner wall of tank A. A liquid cavity is formed between the baffle A and the top of tank A. A liquid inlet regulating structure is provided at the top of tank A to inject liquid into the cavity and automatically stabilize the liquid level. An inverted conical opening A is provided at the bottom of tank A, and a liquid level stabilizing structure is provided at the inverted conical opening A. Below the inverted conical surface is a... A partition B is sealed to the inner wall of tank A. The partition B is densely covered with leakage holes. The upper edge of the leakage hole is an arc surface. An evaporation tube is installed inside the leakage hole. An annular gap is formed between the outer wall of the evaporation tube and the inner wall of the leakage hole. The upper end of the evaporation tube is connected to the air inlet pipe A. The lower end of the evaporation tube is connected to a conical tube. The lower end of the conical tube is connected to a condenser tube. The diameter of the condenser tube is smaller than the diameter of the evaporation tube. Several air inlet pipes B are installed on the partition B. The upper end of the air inlet pipe B is connected to the air inlet pipe A. The lower end of the air inlet pipe B is lower than the lower end of the condenser tube.

[0014] A steam collection unit is used to collect water vapor released from the evaporation and concentration unit for recycling.

[0015] In one embodiment, a conical ring plate is provided on the lower outer wall of the condenser tube.

[0016] In one embodiment, the liquid inlet regulating structure includes a guide sleeve disposed on the top of the tank A. The top of the guide sleeve has an exhaust hole, and the side wall of the guide sleeve is provided with a liquid inlet pipe A communicating with it. A liquid inlet pipe B is sealed and slidably disposed inside the guide sleeve. The side wall of the liquid inlet pipe B has a liquid inlet, which is opposite to the liquid inlet pipe A. A float B is disposed on the liquid inlet pipe B, and a liquid inlet groove is provided at the lower end of the liquid inlet pipe B.

[0017] In one embodiment, the upper end of the guide sleeve is provided with two guide rods B, which slide within the guide hole at the top of the guide sleeve.

[0018] In one embodiment, the liquid level stabilizing structure at the inverted cone opening A includes four guide rods A, with floats A slidably disposed on the four guide rods A. The lower end of each float A is connected to a cone plug A that controls the opening of the inverted cone opening A via a connecting rod A. The upper end of each guide rod A is provided with a limiting block A that cooperates with the floats A.

[0019] In one embodiment, the partition A is integrally connected to the top of the tank A via a connecting rod B, and a drain pipe is provided at the lower end of the inverted conical opening A.

[0020] In one embodiment, a ring with the same inner diameter as the leakage hole is provided at the lower end of the hole.

[0021] In one embodiment, the inner wall of the leakage hole is integrally connected to the outer wall of the corresponding evaporation tube by four circumferentially evenly distributed connecting blocks, and a connecting rod C is connected between the lower end of the evaporation tube and the lower end of the adjacent evaporation tube.

[0022] In one embodiment, the steam collection assembly includes a tank B, which is fixed to the ground by support legs. The tank B is connected to a tank A via a connecting pipe on its side wall, which is located below the condenser pipe. The top of the tank B has a steam outlet, which is connected to an air inlet pipe A via a heating or pressurizing circulation device. The bottom of the tank B has an inverted conical opening B, at which a liquid level stabilizing structure is provided. A drain pipe is provided at the lower end of the inverted conical opening B.

[0023] In one embodiment, the liquid level stabilizing structure at the inverted cone B includes four guide rods C, with floats C slidably disposed on the four guide rods C. The lower end of each float C is connected to a cone plug B that controls the opening of the inverted cone B via a connecting rod D. The upper end of each guide rod C is provided with a limiting block B that cooperates with the floats C.

[0024] The beneficial effects of this invention are:

[0025] 1. This invention employs a small-diameter evaporator tube, allowing steam to flow through the tube. This effectively increases the adhesion area of ​​the liquid film on the outside of the evaporator tube and improves the evaporation and concentration efficiency of the liquid film. Simultaneously, the liquid film adheres and flows down the outside of the evaporator tube without affecting the emission of steam generated during the concentration of lithium sulfate solution or the formation of the liquid film. This ensures that the emission of steam generated during the concentration of lithium sulfate solution and the formation of the liquid film are not limited by the diameter of the evaporator tube. Consequently, the diameter of the evaporator tube can be minimized while ensuring the effective passage of steam, thereby maximizing the adhesion and evaporation area of ​​the liquid film and improving the evaporation and concentration efficiency of the lithium sulfate solution.

[0026] 2. In this invention, the evaporator tube has a lithium sulfate solution attached to its outer wall for evaporation and concentration. Therefore, the crystals formed by the concentration of lithium sulfate solution will only adhere to the outside of the evaporator tube and will not block the evaporator tube, thus preventing the water vapor generated by the evaporation and concentration of lithium sulfate solution from being discharged or affecting the effective formation of the liquid film. Moreover, the crystals formed on the outside of the evaporator tube are easier to clean.

[0027] 3. The present invention ensures that the liquid level on the baffle A fluctuates within a very small range through the structure on the liquid inlet pipe A and liquid inlet pipe B at the top of tank A, and ensures that the lithium sulfate solution on the baffle B is always at a liquid level close to a liquid film state by the annular gap formed between the baffle A and the inverted conical surface on the inner wall of tank A, thereby achieving the purpose of automatic liquid level control. In turn, it ensures that the lithium sulfate solution on the baffle B enters the leakage hole or connecting block and always adheres to the evaporation tube in a liquid film state and flows downward.

[0028] 4. The structure at the inverted conical opening A at the bottom of tank A for draining liquid and the inverted conical opening B at the bottom of tank B for draining water in this invention can automatically control the liquid level at the bottom of tank A and tank B, ensuring that the liquid at the bottom of tank A and tank B is always sealed to the inverted conical openings A and B, preventing hot steam leakage, ensuring that all hot steam is effectively recovered and utilized, and avoiding heat waste.

[0029] 5. In this invention, the lower end of the steam pipe is connected to a condenser pipe with a diameter smaller than that of the steam pipe via a tapered pipe. This allows the steam source water vapor to condense into liquid water inside the steam pipe after flowing and heating up. As the liquid water in the condenser pipe falls, it generates a piston effect and further accelerates the flow and heat release of the steam source water vapor inside the steam pipe, thereby improving the evaporation and concentration of the liquid film on the outside of the steam pipe.

[0030] 6. In this invention, the air inlet pipe B can rapidly vaporize the liquid water discharged from the condenser pipe without causing the liquid water to fall to the bottom of the tank A, thus diluting the lithium sulfate solution that has already been concentrated at the bottom of the tank A. At the same time, it can further heat and evaporate the lithium sulfate solution that flows down the evaporation pipe and is concentrated, ensuring that the lithium sulfate solution at the bottom of the tank A has a high and stable concentration.

[0031] 7. In this invention, the conical ring plate on the outer side of the end of the condenser tube can effectively separate the lithium sulfate solution flowing down from the outside from the liquid water falling inside, ensuring that the condensate can easily come into contact with hot steam and evaporate again. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall invention.

[0033] Figure 2 This is a schematic cross-sectional view of the entire invention.

[0034] Figure 3 This is a schematic cross-sectional view of the upper structure of the evaporation and concentration component in this invention.

[0035] Figure 4 This is a schematic cross-sectional view of the middle structure of the evaporation and concentration component in this invention.

[0036] Figure 5 This is a schematic cross-sectional view of the lower end structure of the evaporation and concentration component in this invention.

[0037] Figure 6 This is a schematic cross-sectional view of the evaporator tube and the leakage hole on the partition B in this invention.

[0038] Figure 7 This is a schematic diagram of the connection between condenser tubes in this invention.

[0039] Figure 8 These are schematic cross-sectional views of the evaporator tube and the leakage hole on the partition B in this invention.

[0040] Figure 9 This is a schematic cross-sectional view of the connection between the evaporator, the cone tube, and the condenser tube in this invention.

[0041] Figure 10 This is a schematic cross-sectional view of the lower end structure of the condenser tube in this invention.

[0042] Figure 11 This is a schematic cross-sectional view of the lower end structure of the steam collection assembly in this invention.

[0043] Figure 12 This is a schematic diagram of a large-diameter liquid film concentration structure in a traditional falling film evaporator.

[0044] Figure 13 This is a schematic diagram of a small-diameter liquid film concentration structure in a traditional falling film evaporator.

[0045] Labels in the diagram:

[0046] 101. Support leg; 102. Connecting pipe;

[0047] 200. Evaporation and concentration assembly; 201. Tank A; 202. Inverted conical surface; 203. Inverted conical opening A; 204. Drain pipe; 205. Conical plug A; 206. Connecting rod A; 207. Float A; 208. Guide rod A; 209. Limiting block A; 210. Guide sleeve; 211. Exhaust port; 212. Inlet pipe A; 213. Inlet pipe B; 214. Inlet port; 215. 216. Liquid tank; 217. Guide rod B; 218. Float B; 219. Baffle A; 220. Drain hole; 221. Arc surface; 222. Connecting block; 223. Ring sleeve; 224. Evaporator tube; 225. Conical tube; 226. Condenser tube; 227. Conical ring plate; 228. Connecting rod C; 229. Inlet pipe A; 230. Inlet pipe B; 231. Connecting rod B;

[0048] 300. Steam collection assembly; 301. Tank body B; 302. Inverted cone port B; 303. Drain pipe; 304. Cone plug B; 305. Connecting rod D; 306. Float C; 307. Guide rod C; 308. Limiting block B; 309. Steam outlet;

[0049] 401. Upper cavity; 402. Concentration tube. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0051] The serial numbers assigned to components in this document, such as "first," "second," etc., are merely used to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0052] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0053] like Figure 1-11 As shown, a falling film evaporation device for lithium sulfate solution is used to concentrate lithium sulfate solution, comprising:

[0054] An evaporation and concentration assembly 200 is used to concentrate lithium sulfate solution. The evaporation and concentration assembly 200 includes a tank A201, which is fixed to the ground by support legs 101. The upper inner wall of the tank A201 has an inverted conical surface 202. A baffle A218 is disposed above the inverted conical surface 202, forming an annular gap between the baffle A218 and the inner wall of the tank A201. A liquid cavity is formed between the baffle A218 and the top of the tank A201. A liquid inlet adjustment structure is provided at the top of the tank A201 to inject liquid into the liquid cavity and automatically stabilize the liquid level. An inverted conical opening A203 is provided at the bottom of the tank A201, and a liquid level stabilizing structure is provided at the inverted conical opening A203. A connection is provided below the inverted conical surface 202 to the inner wall of the tank A201. A sealed partition B219 is provided, on which numerous leakage holes 220 are distributed. The upper edge of the leakage hole 220 is an arc surface 221. An evaporator tube 224 is installed inside the leakage hole 220. An annular gap is formed between the outer wall of the evaporator tube 224 and the inner wall of the leakage hole 220. The upper end of the evaporator tube 224 is connected to the air inlet pipe A229. The lower end of the evaporator tube 224 is connected to a conical tube 225. The lower end of the conical tube 225 is connected to a condenser tube 226. The diameter of the condenser tube 226 is smaller than the diameter of the evaporator tube 224. Several air inlet pipes B230 are provided on the partition B219. The upper end of the air inlet pipe B230 is connected to the air inlet pipe A229. The lower end of the air inlet pipe B230 is lower than the lower end of the condenser tube 226.

[0055] The steam collection component 300 is used to collect the water vapor released by the evaporation and concentration component 200 for recycling.

[0056] This invention employs a small-diameter evaporator tube 224, allowing steam to flow through the tube. This effectively increases the adhesion area of ​​the liquid film on the outside of the evaporator tube 224 and improves the evaporation and concentration efficiency. The discharge of steam generated during lithium sulfate solution concentration and the formation of the liquid film are not limited by the diameter of the evaporator tube 224. Consequently, the diameter of the evaporator tube 224 can be minimized while ensuring effective passage of steam, maximizing the area for liquid film adhesion and evaporation, and improving the evaporation and concentration efficiency of the lithium sulfate solution. Because the evaporator tube 224 in this invention has the lithium sulfate solution attached and concentrated on its outer wall, crystals formed during the concentration process only adhere to the outside of the evaporator tube 224 and do not block the tube, preventing the steam from being discharged or affecting the effective formation of the liquid film. Furthermore, the crystals formed on the outside of the evaporator tube 224 are easier to clean.

[0057] In a further embodiment, such as Figure 10 As shown, a conical ring plate 227 is provided on the lower outer wall of the condenser tube 226.

[0058] In a further embodiment, such as Figure 3 As shown, the liquid inlet adjustment structure includes a guide sleeve 210, which is disposed on the top of the tank body A201. The top of the guide sleeve 210 is provided with an exhaust hole 211. The side wall of the guide sleeve 210 is provided with a liquid inlet pipe A212 communicating with it. A liquid inlet pipe B213 is sealed and slidably disposed inside the guide sleeve 210. The side wall of the liquid inlet pipe B213 is provided with a liquid inlet 214, which is opposite to the liquid inlet pipe A212. A float B217 is provided on the liquid inlet pipe B213. A liquid inlet groove 215 is provided at the lower end of the liquid inlet pipe B213.

[0059] The present invention achieves automatic control of liquid level through the liquid inlet adjustment structure on the liquid inlet pipe A212 and liquid inlet pipe B213 at the top of tank A201, thereby ensuring that the lithium sulfate solution on the baffle B219 enters the leakage hole 220 or the connecting block 222 and always adheres to the evaporation pipe 224 in a liquid film state and flows downward.

[0060] In a further embodiment, such as Figure 3 As shown, the upper end of the guide sleeve 210 is provided with two guide rods B216, and the guide rods B216 slide in the guide hole at the top of the guide sleeve 210.

[0061] In a further embodiment, such as Figure 5 As shown, the liquid level stabilizing structure at the inverted conical opening A203 includes four guide rods A208. Floats A207 are slidably mounted on the four guide rods A208. The lower end of each float A207 is connected to a cone plug A205 that controls the opening of the inverted conical opening A203 via a connecting rod A206. A limiting block A209 that cooperates with the float A207 is provided at the upper end of each guide rod A208.

[0062] The liquid level stabilization structure at the inverted conical opening A203 at the bottom of tank A201 for draining liquid in this invention can prevent the hot steam in tank A201 from leaking, ensuring that all the hot steam is effectively recovered and utilized, and avoiding heat waste.

[0063] In a further embodiment, such as Figure 7 , 8 As shown, the partition A218 is integrally connected to the top of the tank A201 via the connecting rod B231, and the lower end of the inverted conical opening A203 is provided with a drain pipe 204.

[0064] In a further embodiment, such as Figure 6 , 8 As shown, a ring 223 with the same inner diameter as the leakage hole 220 is provided at the lower end of the hole.

[0065] In a further embodiment, such as Figure 7 ,8 As shown, the inner wall of the leakage hole 220 is integrally connected to the outer wall of the corresponding evaporation tube 224 through four circumferentially evenly distributed connecting blocks 222. A connecting rod C228 is connected between the lower end of the evaporation tube 224 and the lower end of the adjacent evaporation tube 224. The connecting blocks can play a vibration-damping role, ensuring that the size of the leakage hole remains unchanged when the equipment vibrates.

[0066] In a further embodiment, such as Figure 2 As shown, the steam collection assembly 300 includes a tank B301, which is fixed to the ground by a support leg 101. The tank B301 is connected to the tank A201 through a connecting pipe 102 on the side wall. The connecting pipe 102 is located below the condenser pipe 226. The top of the tank B301 has a steam outlet 309, which is connected to the air inlet pipe A229 through a heating or pressurizing circulation device. The bottom of the tank B301 has an inverted conical opening B302, and a liquid level stabilizing structure is provided at the inverted conical opening B302. A drain pipe 303 is provided at the lower end of the inverted conical opening B302.

[0067] In a further embodiment, such as Figure 11 As shown, the liquid level stabilizing structure at the inverted conical opening B302 includes four guide rods C307. A float C306 is slidably mounted on the four guide rods C307. The lower end of the float C306 is connected to a cone plug B304 that controls the opening of the inverted conical opening B302 via a connecting rod D305. A limiting block B308 that cooperates with the float C306 is provided at the upper end of the guide rods C307.

[0068] The liquid level stabilization structure at the inverted conical opening B302 at the bottom of the tank B301 in this invention can prevent hot steam from leaking, ensure that all hot steam is effectively recovered and utilized, and avoid heat waste.

[0069] The overall operation flow of this invention is as follows:

[0070] The liquid cavity above partition A218 contains lithium sulfate solution, and the liquid level of the lithium sulfate solution is stable at a certain height. Float B217 floats on the surface of the lithium sulfate solution. The inlet 214 on inlet pipe B213 is partially opposite to inlet pipe A212 but not completely opposite to it. The liquid level of concentrated lithium sulfate solution at inverted conical opening A203 is maintained at a stable height and is closed to inverted conical opening A203. Conical plug A205 is at a certain opening to inverted conical opening A203. Float A207 floats on the surface of concentrated lithium sulfate solution. The liquid water level at inverted conical opening B302 is maintained at a stable height and is closed to inverted conical opening A203. Conical plug B304 is at a certain opening to inverted conical opening B302. Float C306 floats on the surface of liquid water.

[0071] When the liquid level on partition A218 decreases, float B217 decreases accordingly. Under its own weight, inlet pipe B213 moves synchronously with float B217, increasing the opening of inlet port 214 on inlet pipe B213. This increases the flow rate of lithium sulfate solution from inlet pipe A212 into the liquid cavity above partition A218 via inlet port 214, thus replenishing the solution in the liquid cavity and raising the liquid level of lithium sulfate solution in the cavity. Float B217 rises with the liquid level and drives inlet pipe B213 to rise synchronously. The opening of inlet port 214 on inlet pipe B213 decreases, reducing the inlet flow rate of inlet pipe A212, thus keeping the liquid level in the liquid cavity above partition A218 within a stable range.

[0072] When the liquid level on partition A218 rises, float B217 rises with the liquid level. Under its own weight, inlet pipe B213 moves synchronously with float B217. The opening of inlet port 214 on inlet pipe B213 decreases, reducing the flow rate of lithium sulfate solution from inlet pipe A212 into the liquid cavity above partition A218 via inlet port 214. This reduces the replenishment of solution in the liquid cavity, causing the lithium sulfate solution level in the liquid cavity to drop. Float B217 then drops with the liquid level and drives inlet pipe B213 to drop synchronously. The opening of inlet port 214 on inlet pipe B213 increases, increasing the inlet flow rate of inlet pipe A212, thus keeping the liquid level in the liquid cavity above partition A218 within a stable range.

[0073] The lithium sulfate solution in the liquid cavity above partition A218 flows slowly through the annular gap between partition A218 and the inner wall of tank A201, guided by the inverted conical surface 202, in a liquid film state from the inner wall of tank A201 to partition B219. The lithium sulfate solution film reaching partition B219 adheres to the evaporator 224 through the arc surface 221 of the leakage hole 220 and the annular gap between it and the evaporator tube 224, and moves downwards along the outer wall of the evaporator tube 224. Simultaneously, high-temperature water vapor with a certain pressure is introduced into the evaporator tube 224 through the air inlet pipe. As the water vapor moves downwards in the evaporator tube 224, it heats the evaporator tube 224, thereby heating the solution adhering to the outer wall of the evaporator tube 224. The lithium sulfate solution on the outer side of the tube is heated and evaporated for concentration. Water vapor passes through the evaporation tube 224 and reaches the cone tube 225, where it partially releases heat and condenses, resulting in a water vapor mixture inside the cone tube 225. When the water vapor enters and reaches the condenser tube 226, it completely condenses into liquid water. The liquid water in the condenser tube 226 moves downward under the combined action of its own weight and the pressure of the water vapor above. The downward-moving liquid water moves in the condenser tube 226 in a piston-like motion. This piston-like motion of the liquid water in the condenser tube 226 further drives the water vapor above to move downward, improving the heat release efficiency of the water vapor. This, in turn, improves the evaporation and concentration efficiency of the lithium sulfate solution on the outer wall of the evaporation tube 224 by the water vapor in the evaporation tube 224.

[0074] As the lithium sulfate solution flows along the outer wall of the evaporation tube 224, it is effectively evaporated and concentrated, eventually falling to the bottom of the tank A201 under its own weight via the conical ring plate 227. The concentrated lithium sulfate solution at the bottom of the tank A201 is discharged through the inverted conical outlet A203. Guided by the conical ring plate 227, the lithium sulfate solution does not easily mix with the liquid water discharged from the condenser tube 226, thus ensuring that the steam can easily contact the condensate and evaporate again. Since the lithium sulfate solution flows downward from the outer wall of the evaporation tube 224, the crystals formed during the evaporation and concentration process only adhere to the outer wall of the evaporation tube 224 and do not clog it, making them easy to clean. They also do not obstruct the discharge of water vapor and maintain the lithium sulfate solution in a liquid film state, ensuring the efficient falling film evaporation of the lithium sulfate solution.

[0075] Meanwhile, the intake pipe B230 discharges high-temperature water vapor into the space below the condenser pipe 226 to effectively evaporate the liquid water discharged from the condenser pipe 226 without causing the liquid water to fall into the concentrated lithium sulfate solution at the bottom of the tank A201, ensuring that the concentration of the lithium sulfate solution at the bottom of the tank A201 is not affected. At the same time, steam is replenished to facilitate steam circulation. Moreover, the high-temperature water vapor entering the tank A201 from the intake pipe B230 further evaporates and concentrates the concentrated lithium sulfate solution falling from the evaporation pipe 224, thereby improving the concentration efficiency of the lithium sulfate solution.

[0076] After the lithium sulfate solution moves from the evaporator 224 through the conical tube 225 to the outer wall of the condenser 226, because the diameter of the condenser 226 is smaller than the diameter of the evaporator 224, the lithium sulfate solution on the outer wall of the evaporator 224 will have an increased flow velocity when it reaches the outer side of the condenser 226 due to the smaller diameter. The lithium sulfate solution with a larger flow velocity on the outer wall of the condenser 226 will drive the lithium sulfate solution on the outer wall of the evaporator 224 to move faster, thereby improving the evaporation and concentration efficiency of the lithium sulfate solution on the outer wall of the evaporator 224.

[0077] When the liquid level at the bottom of tank A201 decreases, float A207 decreases along with the liquid level. Float A207 drives cone plug A205 to reduce the opening of inverted cone opening A203, thereby reducing the flow rate of solution discharged from inverted cone opening A203 through drain pipe 204. This causes the liquid level in tank A201 to gradually increase and return to its original height, ensuring that inverted cone opening A203 is always closed by the solution, preventing high-temperature water vapor entering tank A201 from leaking through inverted cone opening A203 and causing heat loss and waste.

[0078] Water vapor in tank A201 enters tank B301 through connecting pipe 102 under negative pressure. Water vapor entering tank B301 is then circulated through steam outlet 309 and heating or pressurizing circulation equipment to inlet pipe A229 under negative pressure, thereby realizing the recycling of high-temperature steam.

[0079] After water vapor enters tank B301, a small portion of the water vapor condenses into liquid water, reaching the bottom of tank B301. When the liquid water level at the bottom of tank B301 decreases, float C306 decreases along with the liquid level. Float C306 drives cone plug B304 to reduce the opening of inverted cone opening B302, thus reducing the water flow rate discharged through drain pipe 303 from inverted cone opening B302. Consequently, the liquid level in tank B301 gradually increases to restore the original liquid level, ensuring that inverted cone opening B302 is always closed by liquid water, preventing water vapor entering tank B301 from leaking through inverted cone opening B302 and causing heat loss and waste.

Claims

1. A falling film evaporation device for lithium sulfate solution, used for concentrating lithium sulfate solution, characterized in that, include: An evaporation and concentration assembly is used to concentrate lithium sulfate solution. The assembly includes a tank A, which is fixed to the ground by legs. The upper inner wall of tank A has an inverted conical surface. A baffle A is positioned above the inverted conical surface, forming an annular gap between the baffle A and the inner wall of tank A. A liquid cavity is formed between the baffle A and the top of tank A. A liquid inlet regulating structure is provided at the top of tank A to inject liquid into the cavity and automatically stabilize the liquid level. An inverted conical opening A is provided at the bottom of tank A, and a liquid level stabilizing structure is provided at the inverted conical opening A. Below the inverted conical surface is a... A partition B is sealed to the inner wall of tank A. The partition B is densely covered with leakage holes. The upper edge of the leakage hole is an arc surface. An evaporation tube is installed inside the leakage hole. An annular gap is formed between the outer wall of the evaporation tube and the inner wall of the leakage hole. The upper end of the evaporation tube is connected to the air inlet pipe A. The lower end of the evaporation tube is connected to a conical tube. The lower end of the conical tube is connected to a condenser tube. The diameter of the condenser tube is smaller than the diameter of the evaporation tube. Several air inlet pipes B are installed on the partition B. The upper end of the air inlet pipe B is connected to the air inlet pipe A. The lower end of the air inlet pipe B is lower than the lower end of the condenser tube. A steam collection unit is used to collect water vapor released from the evaporation and concentration unit for recycling.

2. The lithium sulfate solution falling film evaporation device according to claim 1, characterized in that, A conical ring plate is provided on the lower outer wall of the condenser tube.

3. The falling film evaporation device for lithium sulfate solution according to claim 1, characterized in that, The liquid inlet regulating structure includes a guide sleeve, which is disposed on the top of the tank A. The top of the guide sleeve has an exhaust hole. The side wall of the guide sleeve is provided with a liquid inlet pipe A communicating with it. A liquid inlet pipe B is sealed and slidably disposed inside the guide sleeve. The side wall of the liquid inlet pipe B has a liquid inlet, which is opposite to the liquid inlet pipe A. A float B is disposed on the liquid inlet pipe B. A liquid inlet groove is provided at the lower end of the liquid inlet pipe B.

4. The lithium sulfate solution falling film evaporation device according to claim 3, characterized in that, The upper end of the guide sleeve is provided with two guide rods B, which slide within the guide hole at the top of the guide sleeve.

5. The lithium sulfate solution falling film evaporation device according to claim 1, characterized in that, The liquid level stabilization structure at the inverted cone opening A includes four guide rods A, with floats A slidably mounted on the four guide rods A. The lower end of each float A is connected to a cone plug A that controls the opening of the inverted cone opening A via a connecting rod A. The upper end of each guide rod A is provided with a limiting block A that cooperates with the floats A.

6. The lithium sulfate solution falling film evaporation device according to claim 1, characterized in that, The partition A is integrally connected to the top of the tank A via the connecting rod B, and a drain pipe is provided at the lower end of the inverted conical opening A.

7. The falling film evaporation device for lithium sulfate solution according to claim 1, characterized in that, A ring with the same inner diameter as the leakage hole is provided at the lower end of the hole.

8. The lithium sulfate solution falling film evaporation device according to claim 1, characterized in that, The inner wall of the leakage hole is integrally connected to the outer wall of the corresponding evaporation tube by four circumferentially evenly distributed connecting blocks, and a connecting rod C is connected between the lower end of the evaporation tube and the lower end of the adjacent evaporation tube.

9. A falling film evaporation device for lithium sulfate solution according to claim 1, characterized in that, The steam collection assembly includes a tank B, which is fixed to the ground by support legs. The tank B is connected to a tank A through a connecting pipe on its side wall, which is located below the condenser pipe. The top of the tank B has a steam outlet, which is connected to the inlet pipe A through a heating or pressurizing circulation device. The bottom of the tank B has an inverted conical opening B, at which a liquid level stabilizing structure is provided. A drain pipe is provided at the lower end of the inverted conical opening B.

10. A falling film evaporation device for lithium sulfate solution according to claim 9, characterized in that, The liquid level stabilization structure at the inverted cone opening B includes four guide rods C, with floats C slidably mounted on the four guide rods C. The lower end of each float C is connected to a cone plug B that controls the opening of the inverted cone opening B via a connecting rod D. The upper end of each guide rod C is provided with a limiting block B that cooperates with the floats C.

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