Plate type falling film evaporator

Abstract

The invention discloses a plate type falling film evaporator. The evaporator comprises an evaporator tank body, a feed liquid evaporation plate device, a feed liquid distribution device, a feed liquid circulating device, a steam discharging device and a feeding pipeline, the feed liquid evaporation plate device comprises an evaporation plate mechanism, a fixed bracket, a descaling connecting frame and a descaling metal strip; a liquid film evaporation area is formed through the feed liquid evaporation plate device, uniform liquid distribution is achieved through the feed liquid distribution device, non-evaporated feed liquid flows back through the feed liquid circulation device, secondary steam is discharged through the steam discharging device, and raw materials are supplemented through the feeding pipeline; the thermal expansion coefficient of the descaling metal strip is larger than that of the evaporation plate mechanism, micro displacement is generated during heating or the descaling metal strip abuts against and slides to disturb the plate face, scale layer attachment is damaged, the scale layer is promoted to fall off, automatic reset is achieved during cooling, and self-adaptive descaling without external force driving is achieved. Passive scale removal is achieved through the thermal expansion difference, the heat transfer efficiency is improved, the operation period is prolonged, and the cleaning frequency and the maintenance cost are reduced.

Description

Technical Field

[0001] This application relates to the field of evaporation separation heat exchange equipment technology, and in particular to a plate falling film evaporator. Background Technology

[0002] Existing falling film evaporators are widely used in chemical, pharmaceutical, and food industries to achieve solvent evaporation and separation in feed liquids through heating. Traditional devices mostly adopt a tubular structure, with the feed liquid forming a liquid film flowing down the inner wall of the heating tube. However, for materials prone to scaling, during long-term operation, due to the thin liquid film and the film-pulling effect of secondary steam, a dense scale layer is easily formed on the heating surface, leading to increased heat transfer resistance and decreased heat exchange efficiency. At the same time, the scale inside the tube is difficult to remove, the cleaning cycle is short and the operation is cumbersome, resulting in high maintenance costs. Summary of the Invention

[0003] In order to improve the shortcomings of existing falling film evaporators that are prone to scaling and difficult to clean during liquid film flow, this application provides a plate-type falling film evaporator.

[0004] The plate-type falling film evaporator provided in this application adopts the following technical solution: A plate-type falling film evaporator includes an evaporator tank, a liquid evaporation plate device inserted into the evaporator tank and connected to the inner side wall of the evaporator tank, a liquid distribution device connected to the upper end of the liquid evaporation plate device, a liquid circulation device connected to the bottom of the evaporator tank and extending above the liquid distribution device, a steam discharge device connected to the upper end of the evaporator tank and used for steam discharge, and a feed pipe connected to the evaporator tank. The liquid evaporation plate device includes evaporation plate mechanisms arranged in a horizontally spaced array, a fixed bracket connected to the side edges of the plurality of evaporation plate mechanisms and connected to the inner side wall of the evaporator tank, a descaling connecting frame connected to the outer side wall of the evaporation plate mechanisms, and a descaling metal strip movably connected to the descaling connecting frame; the coefficient of thermal expansion of the descaling metal strip is greater than the coefficient of thermal expansion of the evaporation plate mechanism.

[0005] By adopting the above technical solution, the liquid evaporation plate device is used to provide a liquid film evaporation area, the liquid distribution device is used to evenly distribute the fed liquid onto the outer surface of each evaporation plate mechanism, the liquid circulation device is used to return the incompletely evaporated liquid to the distribution end for continued evaporation, the steam discharge device is used for secondary steam discharge, and the feed pipe is used to replenish the original liquid into the evaporator tank. The thermal expansion coefficient of the descaling metal strip in this application is greater than that of the evaporation plate mechanism. When the evaporator is heated and running, due to the difference in thermal expansion between the descaling metal strip and the evaporation plate mechanism, the descaling metal strip generates a slight displacement or thermal expansion force in the vertical direction. Through the top pressure or sliding action, the surface of the evaporation plate mechanism in contact with the descaling metal strip is periodically disturbed, which can peel off the initially formed scale layer or prevent the scale layer from adhering firmly. During the heating or cooling stage, the descaling metal strip returns to its original position as the temperature decreases, realizing a passive descaling process without external force. The descaling mechanism driven by the thermal expansion difference in this application can extend the operating cycle of the evaporation plate mechanism, improve the evaporation heat transfer efficiency, reduce the cleaning frequency and the evaporator operating cost.

[0006] Preferably, the evaporation plate mechanism includes a first vertical plate, a second vertical plate connected to the periphery of the first vertical plate, and welding portions disposed on the first vertical plate and the second vertical plate and respectively used to connect the first vertical plate and the second vertical plate; Multiple welded portions are arranged in a honeycomb array along the outer surfaces of the first vertical plate and the second vertical plate, respectively; after the welded portions are welded and formed, a welding groove is formed at the location of the welded portion, and an outwardly bulging portion is formed in the non-welded area between adjacent welded portions on the first vertical plate and the second vertical plate, respectively; the welded portions, the first vertical plate and the second vertical plate are arranged in a matrix along the outer surfaces of the first vertical plate and the second vertical plate, respectively; the welded portions, the first vertical plate and the second vertical plate are arranged to form a heat exchange medium cavity.

[0007] By adopting the above technical solution, the first vertical plate and the second vertical plate are welded to form an integral heat exchange unit, and the welded parts are distributed in a honeycomb array on the outer surfaces of the first and second vertical plates; the bulges are arranged in a matrix along the plate surfaces of the first and second vertical plates to form a three-dimensional disturbance structure; this application achieves efficient heat transfer when the heating steam flows through the heat exchange medium cavity, and the bulges cause local disturbance and velocity changes in the liquid film flow path, which promotes liquid film renewal, enhances heat exchange, and inhibits dry walls and scaling; the continuous transition area of ​​the bulge structure of the bulges helps the scale layer peel off and reduces the adhesion firmness, extends the operating cycle, improves heat transfer efficiency, and reduces cleaning and maintenance costs.

[0008] Preferably, the liquid evaporation plate device further includes a steam inlet pipe connected to the upper end of the plurality of evaporation plate mechanisms and communicating with the heat exchange medium cavity, a condensation collection tank connected to the lower end of the plurality of evaporation plate mechanisms and communicating with the heat exchange medium cavity, a gas discharge pipe connected to the upper side of the condensation collection tank and extending to the outside of the evaporator tank, and a condensate discharge pipe connected to the lower side of the condensation collection tank and extending to the outside of the evaporator tank.

[0009] By adopting the above technical solution, the steam inlet pipe is used to uniformly introduce external heating steam into the evaporator plate mechanism, realizing efficient heat transfer between the evaporator plate mechanisms; the heating steam flows in the heat exchange medium cavity and releases heat before gradually condensing to form condensate, which is collected in the condensate collection tank at the lower end under gravity; the gas discharge pipe is used to discharge the stagnant non-condensable gas or entrained steam to prevent gas accumulation from affecting the condensation efficiency; the condensate discharge pipe is used to centrally discharge the condensate, ensuring that the heat exchange cavity maintains a stable heat transfer and condensation state; this application realizes the orderly entry of steam and the separate discharge of condensate. Through the dual-channel exhaust and drainage design with upper and lower separation, the problems of gas-liquid co-flow and condensation blockage are effectively avoided, thereby improving the heat exchange efficiency, stabilizing the operation of the evaporator, and improving the overall energy efficiency.

[0010] Preferably, the liquid evaporation plate device further includes a descaling vibration mechanism connected to the outer wall of the first vertical plate.

[0011] By adopting the above technical solution, a descaling vibration mechanism is set on the outer wall of the first vertical plate, so that the descaling vibration mechanism applies periodic or continuous vibration to the evaporation plate mechanism during the operation of the evaporator. When the liquid film evaporates on the plate surface of the evaporation plate mechanism, it generates a slight disturbance, which breaks the scale adhesion and promotes the scale to fall off in advance. At the same time, it forms a coupled vibration with the descaling metal strip, further enhancing the descaling effect. This application can achieve descaling without disassembly, improve the self-cleaning ability of the evaporation surface, extend the continuous operation cycle of the equipment, reduce the frequency of manual maintenance and reduce downtime.

[0012] Preferably, the descaling connecting frame includes a limiting clamp plate connected to the outer wall of the evaporation plate mechanism for movably inserting the descaling metal strip, a support base connected to the outer wall of the evaporation plate mechanism and press-fitting the lower end of the descaling metal strip, and a limiting rod assembly fixedly connected to the outer wall of the evaporation plate mechanism and movably inserted into the upper end of the descaling metal strip; the limiting clamp plate and the outer wall of the evaporation plate mechanism are arranged to form an insertion gap, and the descaling metal strip is movably inserted into the insertion gap in the vertical direction; The plurality of descaling connecting brackets and the descaling metal strips are arranged in a spaced array along the width direction of the evaporation plate mechanism, and the plurality of limiting clamps are arranged in a spaced array along the length direction of the evaporation plate mechanism.

[0013] By adopting the above technical solution, the descaling connecting frame guides and limits the descaling metal strip. The descaling metal strip slides up and down along the insertion gap. When it expands due to heat, it is supported by the support seat; when it contracts due to cooling, it is guided back to its original position by the limiting rod assembly, thereby achieving passive lifting and lowering movement with temperature changes. This application ensures that the descaling metal strip remains in contact with the surface of the evaporator plate mechanism and generates micro-disturbances during the thermal cycle, achieving adaptive descaling without external drive. Through the stable guidance and distributed arrangement of the descaling connecting frame, this application can effectively prevent deviation and improve descaling sensitivity. It is not only compact in structure and reliable in operation, but also easy to maintain, thus improving the scale prevention and operational stability of the evaporator.

[0014] Preferably, the width of the support gradually decreases from the middle to both ends.

[0015] By adopting the above technical solution, the width of the support gradually decreases from the middle to the upper and lower ends, forming a streamlined structure, which enables the liquid and steam to flow smoothly, avoids the formation of stagnant areas and reduces flow resistance. During the operation of the evaporator, the descaling metal strips undergo micro-displacement with temperature changes. The support ensures that the descaling metal strips move smoothly and the disturbance is uniform while guiding and supporting them. This application can not only provide descaling support, but also guide the fluid, which can effectively improve evaporation efficiency and reduce liquid film disturbance.

[0016] Preferably, the upper end of the descaling metal strip is provided with a strip-shaped clearance through hole arranged along the length direction of the descaling metal strip; The limiting rod assembly includes a limiting guide rod inserted into the strip-shaped clearance through hole and connected at one end to the outer wall of the evaporator plate mechanism, and a blocking limiting member connected to the other end of the limiting guide rod and close to the outer wall of the descaling metal strip.

[0017] By adopting the above technical solution, the strip-shaped clearance through-hole, together with the limiting guide rod and the blocking limiting component, realizes the guidance and anti-detachment control of the descaling metal strip; the limiting guide rod passes through the strip-shaped clearance through-hole to limit and guide the vertical sliding of the descaling metal strip, and the blocking limiting component prevents the descaling metal strip from shifting or falling out during thermal cycling; the descaling metal strip moves back and forth between the support base and the limiting rod assembly with temperature changes to realize heat-driven descaling; it automatically returns to its original position after cooling; this application can limit the movement path and displacement of the descaling metal strip, prevent jamming and falling off, and ensure the stability and long-term reliability of the descaling action.

[0018] Preferably, the liquid circulation device includes a discharge pipe connected to the bottom of the evaporator tank and communicating with the interior of the evaporator tank, a liquid circulation drive mechanism connected to the discharge pipe, a feeding pipe connected to the feeding drive mechanism and inserted into the interior of the evaporator tank, and a discharge pipe connected to the feeding pipe and located outside the evaporator tank; the feeding pipe extends upward to above the liquid distribution device.

[0019] By adopting the above technical solution, the liquid feed flows into the liquid feed circulation drive mechanism through the discharge pipe, and is then transported back to the liquid feed distribution device through the feed pipe for re-evaporation, forming a continuous circulation loop; at the end of operation, it is discharged through the discharge pipe; this application ensures stable liquid feed circulation, prevents dry walls or thermal shock caused by insufficient liquid volume, improves evaporation efficiency and realizes multiple uses of liquid feed, thereby maintaining the balance of evaporator liquid level and flow rate, and reducing energy consumption and operating costs.

[0020] Preferably, the liquid distribution device includes a liquid distribution storage tray connected to the upper end of the evaporation plate mechanism, a liquid distribution collection tank connected to the feeding pipe and located above the opening end of the liquid distribution storage tray, and liquid distribution pipes connected to both sides of the liquid distribution collection tank and arranged in an array along the length direction of the liquid distribution collection tank; the bottom of the liquid distribution storage tray is provided with a liquid distribution guide hole located above the evaporation plate mechanism and aligned with the side wall of the evaporation plate mechanism.

[0021] By adopting the above technical solution, the liquid distribution device, through the graded liquid distribution structure of the liquid distribution collection tank, the liquid distribution pipe and the liquid distribution storage tray, allows the liquid to enter through the feeding pipe and be distributed sequentially and fall evenly onto the surface of the evaporation plate mechanism through the liquid distribution guide hole, forming a stable and continuous liquid film flow. This application can avoid local dry wall, scaling or gas overflow problems, ensure uniform liquid film distribution and stable flow rate, thereby improving heat transfer efficiency.

[0022] Preferably, the steam discharge device includes a demister mechanism connected to the inner wall of the evaporator tank and located above the liquid distribution device, and a secondary steam discharge pipe connected to the evaporator tank and located above the demister mechanism.

[0023] By adopting the above technical solution, the liquid vapor is separated from the droplets and foam by the demister mechanism during the rising process, and then discharged to the external or downstream system through the secondary steam discharge pipe. This application can prevent the steam from carrying liquid droplets, improve the purity of the secondary steam, reduce energy loss and condensation pollution, and ensure the continuity and operational stability of the evaporation process.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. The liquid evaporation plate device provides a liquid film evaporation area, the liquid distribution device distributes the fed liquid evenly to the outer surface of each evaporation plate mechanism, the liquid circulation device returns the incompletely evaporated liquid to the distribution end for continued evaporation, the steam discharge device discharges secondary steam, and the feed pipe replenishes the original liquid into the evaporator tank. The thermal expansion coefficient of the descaling metal strip in this application is greater than that of the evaporation plate mechanism. When the evaporator is heating, due to the difference in thermal expansion between the descaling metal strip and the evaporation plate mechanism, the descaling metal strip generates a slight displacement or thermal expansion force in the vertical direction. Through top pressure or sliding action, it periodically disturbs the surface of the evaporation plate mechanism in contact with the descaling metal strip, which can peel off the initially formed scale layer or prevent the scale layer from adhering firmly. During the heating or cooling phase, the descaling metal strip returns to its original position as the temperature decreases, realizing a passive descaling process without external force. This application, through a descaling mechanism driven by thermal expansion difference, can extend the operating cycle of the evaporation plate mechanism, improve evaporation heat transfer efficiency, reduce cleaning frequency, and lower evaporator operating costs. 2. The first vertical plate and the second vertical plate are welded to form an integral heat exchange unit. The welded parts are distributed in a honeycomb array on the outer surfaces of the first and second vertical plates. The bulges are arranged in a matrix along the plate surfaces of the first and second vertical plates to form a three-dimensional disturbance structure. This application achieves efficient heat transfer when the heating steam flows through the heat exchange medium cavity. The bulges cause local disturbances and velocity changes in the liquid film flow path, promoting liquid film renewal, enhancing heat transfer, and inhibiting dry walls and scaling. The continuous transition area of ​​the bulge structure helps to remove scale and reduce adhesion, extend the operating cycle, improve heat transfer efficiency, and reduce cleaning and maintenance costs. 3. A descaling vibration mechanism is installed on the outer wall of the first vertical plate. During the operation of the evaporator, the descaling vibration mechanism applies periodic or continuous vibration to the evaporation plate mechanism. When the liquid film evaporates on the surface of the evaporation plate mechanism, it generates a slight disturbance, which breaks the scale adhesion and promotes the scale to fall off in advance. At the same time, it forms a coupled vibration with the descaling metal strip, further enhancing the descaling effect. This application can achieve descaling without disassembly, improve the self-cleaning ability of the evaporation surface, extend the continuous operation cycle of the equipment, reduce the frequency of manual maintenance and reduce downtime. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of an embodiment of this application. Figure 1 .

[0026] Figure 2 This is a cross-sectional structural schematic diagram of the liquid evaporation plate device according to an embodiment of this application.

[0027] Figure 3 This is a cross-sectional view of an embodiment of this application. Figure 2 .

[0028] Figure 4This is a three-dimensional structural schematic diagram of the liquid evaporation plate device according to an embodiment of this application.

[0029] Explanation of reference numerals in the attached figures: 1. Evaporator tank; 2. Feed liquid evaporation plate device; 21. Evaporation plate mechanism; 22. Fixed bracket; 23. Descaling connecting frame; 24. Descaling metal strip; 25. Descaling vibration mechanism; 211. First vertical plate; 212. Second vertical plate; 213. Welding part; 214. Welding groove; 215. Bulging part; 216. Heat exchange medium cavity; 217. Steam inlet pipe; 218. Condensate collection tank; 219. Gas discharge pipe; 220. Condensate discharge pipe; 231. Limiting clamp; 232. Support base; 233. Limiting rod assembly; 234. Insertion gap; 241. Strip-shaped clearance through hole; 2331. Limiting guide rod; 2332. Blocking limiting component; 3. Liquid distribution device; 31. Liquid distribution storage tray; 32. Liquid distribution collection tank; 33. Liquid distribution pipe; 34. Liquid distribution guide hole; 4. Liquid circulation device; 41. Discharge pipe; 42. Liquid circulation drive mechanism; 43. Feeding pipe; 44. Discharge pipe; 5. Steam exhaust device; 51. Demister mechanism; 52. Secondary steam exhaust pipe; 6. Feeding pipe. Detailed Implementation

[0030] The following is in conjunction with the appendix Figures 1 to 4 This application will be described in further detail.

[0031] This application discloses a plate-type falling film evaporator. (Refer to...) Figure 1 A plate-type falling film evaporator includes an evaporator tank 1, a liquid evaporation plate device 2 inserted into the evaporator tank 1 and connected to the inner wall of the evaporator tank 1, a liquid distribution device 3 connected to the upper end of the liquid evaporation plate device 2, a liquid circulation device 4 connected to the bottom of the evaporator tank 1 and extending above the liquid distribution device 3, a steam discharge device 5 connected to the upper end of the evaporator tank 1 and used for steam discharge, and a feed pipe 6 connected to the evaporator tank 1; the liquid evaporation plate device 2 includes evaporation plate mechanisms 21 arranged in a horizontally spaced array, a fixed bracket 22 connected to the side edges of multiple evaporation plate mechanisms 21 and connected to the inner wall of the evaporator tank 1, a descaling connecting frame 23 connected to the outer wall of the evaporation plate mechanisms 21, and a descaling metal strip 24 movably connected to the descaling connecting frame 23; the coefficient of thermal expansion of the descaling metal strip 24 is greater than the coefficient of thermal expansion of the evaporation plate mechanisms 21.

[0032] The evaporation plate device 2 of this application provides a liquid film evaporation area, and the liquid distribution device 3 distributes the fed liquid evenly onto the outer surface of each evaporation plate mechanism 21. The liquid circulation device 4 is connected to the bottom of the evaporator tank 1 and extends above the liquid distribution device 3, forming a circulation loop. The liquid circulation device 4 is used to return the incompletely evaporated liquid to the distribution end for continued evaporation. The steam discharge device 5 is used for secondary steam discharge, and the feed pipe 6 is used to replenish the original liquid into the evaporator tank 1. The thermal expansion coefficient of the descaling metal strip 24 of this application is greater than that of the evaporation plate mechanism 21. When the evaporator is heated and running, the thermal expansion coefficient of the descaling metal strip 24 is greater than that of the evaporation plate mechanism 21. Due to the difference in thermal expansion between the descaling metal strip 24 and the evaporator plate mechanism 21, the descaling metal strip 24 generates a slight displacement or thermal expansion force in the vertical direction. Through the action of pressing or sliding, it periodically disturbs the surface of the evaporator plate mechanism 21 in contact with the descaling metal strip 24, which can peel off the initially formed scale layer or prevent the scale layer from adhering firmly. During the heating or cooling stage, the descaling metal strip 24 returns to its original position as the temperature decreases, realizing a passive descaling process without external force. The descaling mechanism driven by the thermal expansion difference in this application can extend the operating cycle of the evaporator plate mechanism 21, improve the evaporation heat transfer efficiency, reduce the cleaning frequency and the operating cost of the evaporator. The descaling metal strip 24 of this application is preferably made of a metal material with a large coefficient of linear expansion, such as aluminum alloy, brass or austenitic stainless steel, and the evaporation plate mechanism 21 is preferably made of duplex stainless steel or titanium alloy with a small coefficient of expansion, high thermal conductivity and high corrosion resistance. During the heating and cooling cycle, the descaling metal strip 24 undergoes relative displacement due to its large coefficient of expansion, forming periodic pressure and sliding with the surface of the evaporation plate mechanism 21, thereby destroying the adhesion of the scale layer, realizing automatic descaling and improving heat transfer stability and operational reliability.

[0033] Furthermore, such as Figure 2As shown, the evaporation plate mechanism 21 of this application includes a first vertical plate 211 and a second vertical plate 212 welded to the periphery of the first vertical plate 211. The first vertical plate 211 and the second vertical plate 212 are interconnected by multiple welded portions 213. The welded portions 213 are disposed on the opposing surfaces of the first vertical plate 211 and the second vertical plate 212, and are distributed in a honeycomb array on the corresponding outer surfaces. After the first vertical plate 211 and the second vertical plate 212 are welded together by the welded portions 213, the area where the welded portions 213 are located forms a recessed welding groove 214 due to the welding heat. The non-welded areas between adjacent welded portions 213 form outwardly bulging bulges 215 under the action of high-pressure fluid expansion or thermal expansion and contraction. The bulges 215 form a matrix-arranged three-dimensional protrusion structure along the outer surfaces of the first vertical plate 211 and the second vertical plate 212 respectively. The first vertical plate 211, the second vertical plate 212 and the welded portions 213 3. A heat exchange medium cavity 216 for introducing heating steam is formed together. When the evaporator is running, the heating steam flows in the heat exchange medium cavity 216 and transfers heat through the plate wall to the falling film liquid film formed outside the evaporator plate mechanism 21. The arrangement of the bulges 215 causes a nonlinear three-dimensional disturbance structure to be formed on the outer surface of the evaporator plate mechanism 21, thereby inducing local disturbance and flow rate change of the liquid film during the downward flow of the liquid, improving the liquid film renewal frequency and heat transfer intensity, and helping to suppress local scaling and dry wall phenomena. This application enhances the effective heat exchange area and turbulence capacity of the heat transfer surface, and improves the overall evaporation efficiency. The continuous transition area between the bulge structures is conducive to scale peeling and reduces the adhesion of scale, extending the evaporator operating cycle and reducing maintenance costs. The honeycomb array welding plus bulge molding structure of this application improves the structural strength and thermal stability, and is suitable for long-term stable operation in high-intensity heat exchange environments.

[0034] Furthermore, such as Figure 3As shown, the liquid evaporation plate device 2 of this application further includes a steam inlet pipe 217 connected to the upper end of a plurality of evaporation plate mechanisms 21, a condensation collection tank 218 connected to the lower end of the plurality of steam inlet pipes 217, a gas discharge pipe 219 connected to the upper side of the condensation collection tank 218 and extending to the outside of the evaporator tank 1, and a condensate discharge pipe 220 connected to the lower side of the condensation collection tank 218 and extending to the outside of the evaporator tank 1; wherein the steam inlet pipe 217 is connected to the heat exchange medium cavity 216 and is used to introduce external heating steam into the heat exchange medium cavity 216 inside the evaporation plate mechanism 21. When the steam enters the heat exchange medium cavity 216, it flows in the inner cavity and transfers heat through the first vertical plate 211 and the second vertical plate 212 to the liquid film surface on the outer wall. At the same time, the steam gradually condenses during the heat transfer process, forming a liquid film. The condensate is collected under gravity into a condensation collection tank 218 connected to the lower end of the evaporator plate mechanism 21. The condensate and a small amount of entrained steam are discharged from the lower and upper sides of the condensation collection tank 218, respectively. The gas discharge pipe 219 is used to discharge non-condensable gas or entrained gas that enters the upper space of the condensation collection tank 218 to avoid gas accumulation affecting condensation efficiency. The condensate discharge pipe 220 is used to centrally discharge condensate to ensure that the heat exchange medium cavity 216 is continuously in a state of flow and stable condensation. This application not only realizes the orderly introduction of steam and the efficient discharge of condensate, but also effectively prevents the problems of poor condensation and gas-liquid co-flow caused by gas accumulation by setting up a double discharge outlet with upper and lower separation. Thus, the continuity of the whole machine operation and the system energy efficiency are improved without affecting the heat exchange efficiency.

[0035] Specifically, such as Figure 3 As shown, the liquid evaporation plate device 2 of this application also includes a descaling vibration mechanism 25 connected to the outer wall of the first vertical plate 211. The descaling vibration mechanism 25 is installed on the outer surface of the evaporation plate mechanism 21 and is located in the middle of the first vertical plate 211. The descaling vibration mechanism 25 is used to periodically or continuously apply mechanical vibration or impact to the first vertical plate 211 during the operation of the evaporator. When the liquid forms a liquid film on the surface of the evaporation plate mechanism 21 and evaporates during the operation of the evaporator, the descaling vibration mechanism 25 is started simultaneously, so that the evaporation plate mechanism 21 generates micro-vibrations within a certain frequency and amplitude range. On the one hand, it can destroy the adhesion stability of the initial scale layer and cause the scale layer to be disturbed and peeled off before it solidifies. On the other hand, by generating coupled vibration with the descaling metal strip 24, a composite effect is formed between the descaling metal strip 24 and the evaporation plate mechanism 21, thereby enhancing the descaling effect. This application provides a solution to achieve descaling without disassembly, which breaks the scale layer structure by vibration, improves the self-cleaning ability of the evaporation surface, extends the operating cycle of the evaporation plate, and reduces the frequency of manual maintenance and system downtime.

[0036] The descaling vibration mechanism 25 is preferably any one of the following structural forms: electromagnetic vibrator, piezoelectric ceramic vibrating plate, or eccentric wheel vibration assembly. It generates micro-amplitude high-frequency or low-frequency vibrations through periodic driving, causing continuous disturbance on the outer surface of the evaporation plate mechanism 21, thereby preventing scale from solidifying and achieving online descaling.

[0037] More specifically, such as Figure 4 As shown, the descaling connecting frame 23 of this application includes a limiting clamp 231, a support base 232, and a limiting rod assembly 233. The limiting clamp 231, support base 232, and limiting rod assembly 233 are all disposed on the outer wall of the evaporator plate mechanism 21. The limiting clamp 231 and the outer surface of the evaporator plate mechanism 21 together form an insertion gap 234, which provides a guide channel for the descaling metal strip 24 to slide vertically. The descaling metal strip 24 is vertically inserted into the insertion gap 234. The support base 232 is disposed below the limiting clamp 231 and is fixedly connected to the outer wall of the evaporator plate mechanism 21. The upper edge of the support base 232 forms a top-pressing fit with the lower end of the descaling metal strip 24, providing limiting support when the descaling metal strip 24 moves due to thermal expansion. The limiting rod assembly 233 is... The descaling metal strips 24 are arranged in a spaced array along the width of the evaporator plate mechanism 21, which is placed above the limiting clamping plate 231. This allows for distributed descaling control of a large plate surface. The multiple limiting clamping plates 231 are arranged at intervals along the length of the evaporator plate mechanism 21, which helps to strengthen the stable support and guiding control of the descaling metal strips 24 in the longitudinal direction. This application realizes the passive lifting and lowering movement of the descaling metal strips 24 during the thermal expansion and contraction process. By limiting the range and direction of movement through the descaling connecting plate 23, the descaling metal strips 24 are kept in contact with the surface of the evaporator plate mechanism 21 or form micro-disturbances during the temperature cycle, thereby realizing the adaptive descaling function without external drive. This application has a compact structure, sensitive response, convenient installation and maintenance, and can effectively extend the equipment cleaning cycle, improve evaporation stability and operational reliability.

[0038] In addition, such as Figure 4As shown, the support base 232 of this application is disposed on the outer wall of the evaporator plate mechanism 21 and is fixedly connected to the evaporator plate mechanism 21. The upper edge of the evaporator plate mechanism 21 forms a top-press fit with the lower end of the descaling metal strip 24 to support the vertical displacement of the descaling metal strip 24 during thermal expansion and contraction. At the same time, the width of the support base 232 gradually decreases from the middle to the upper and lower ends, so that the support base 232 presents a streamlined structure that is wide and thick in the middle and narrows at the top and bottom. This application avoids the obstruction of the liquid film or steam flow path by the right-angle edge. During the operation of the evaporator, as the temperature rises, the descaling metal strip 24 extends slightly downward due to thermal expansion, and the lower end of the descaling metal strip 24 continuously contacts the support base 232. Maintaining contact or forming a gap displacement, the downward pressing motion is achieved by using thermal expansion. When the temperature decreases, the descaling metal strip 24 shrinks and resets, completing one descaling cycle. During this process, the streamlined support 232 provides stable contact support, while the gradually tapering geometry of the support 232 allows the liquid or steam to flow smoothly without forming local stagnant areas, thereby avoiding disturbance to the liquid film distribution. The support 232 of this application is not only used for guiding and supporting the thermal expansion of the descaling metal strip 24, but also for fluid guidance. It can reduce flow resistance and reduce the risk of liquid film disturbance while ensuring the sensitivity of the descaling mechanism, further improving the evaporation efficiency and operational stability of the evaporator.

[0039] And, as Figure 2 and Figure 4 As shown, the upper end of the descaling metal strip 24 of this application is provided with a strip-shaped clearance through hole 241 arranged along the length direction of the descaling metal strip 24. The strip-shaped clearance through hole 241 is used to cooperate with the insertion and guidance of the limiting rod assembly 233. The limiting rod assembly 233 includes a limiting guide rod 2331 and a blocking limiting member 2332 connected to the outer end of the limiting guide rod 2331. One end of the limiting guide rod 2331 is fixedly connected to the outer wall of the evaporation plate mechanism 21, and the other end passes through the strip-shaped clearance through hole 241 and is connected to the blocking limiting member 2332, so that the limiting guide rod 2331 slides and guides the descaling metal strip 24 within a limited direction. The blocking limiting member 2332 is close to the outer wall of the descaling metal strip 24 and is used to limit the descaling metal strip. The descaling metal strip 24 disengages from the limiting guide rod 2331 to prevent it from detaching or shifting during thermal expansion and contraction cycles. During operation, as the temperature rises, the descaling metal strip 24 shifts vertically under thermal expansion. The upper and lower ends of the descaling metal strip 24 engage with the limiting rod assembly 233 and the support seat 232, respectively, to complete the thermally driven descaling motion. After cooling, the descaling metal strip 24 retracts and resets. The strip-shaped clearance through hole 241 is used for sliding guidance of the limiting guide rod 2331, thereby realizing the expansion and return of the descaling metal strip 24. This application achieves the limitation of the displacement path and maximum displacement of the descaling metal strip 24, avoiding jamming or detachment, and ensuring the descaling stability and long-term operational reliability of the descaling metal strip 24 during multiple temperature cycles.

[0040] Furthermore, such as Figure 3 As shown, the liquid circulation device 4 of this application includes a discharge pipe 41, a liquid circulation drive mechanism 42, a feeding pipe 43, and a discharge pipe 44. The discharge pipe 41 is located at the bottom of the evaporator tank 1 and communicates with the internal space of the evaporator tank 1. The discharge pipe 41 is used to collect liquid that has not been completely evaporated or condensed and returned. The lower end of the discharge pipe 41 is connected to the liquid circulation drive mechanism 42, which provides continuous and stable liquid recirculation power. The outlet of the liquid circulation drive mechanism 42 is connected to the feeding pipe 43. The feeding pipe 43 is inserted upward into the evaporator tank 1 and extends above the liquid distribution device 3. The feeding pipe 43 is used to re-transport the recovered liquid to the liquid distribution device 3. The distribution device 3 performs redistribution, and the feeding pipe 43 is also connected to the discharge pipe 44 located outside the tank body, which facilitates the discharge of the separated liquid after the evaporator operation is completed. During the operation of the evaporator, the liquid enters the evaporator tank 1 from the feeding pipe 6, flows from the bottom of the evaporator tank 1 into the discharge pipe 41, and is then sent back to the distribution area by the feeding pipe 43 after passing through the liquid circulation drive mechanism 42, forming a closed continuous circulation loop. This application can reduce the dry wall or thermal shock problems caused by insufficient liquid volume or uneven distribution during the operation of the evaporator, while ensuring the full utilization and multiple uses of the liquid in the evaporator, which is conducive to improving evaporation efficiency, reducing resource waste, and maintaining the dynamic balance of liquid level and flow rate in the system. The liquid circulation drive mechanism 42 is used to return the liquid discharged from the bottom of the evaporator tank 1 and re-transport it to the feeding pipe 43. The liquid circulation drive mechanism 42 is preferably a liquid conveying device such as a centrifugal pump, magnetic pump, screw pump or pneumatic diaphragm pump.

[0041] Furthermore, such as Figure 3As shown, the liquid distribution device 3 of this application includes a liquid distribution storage tray 31, a liquid distribution collection tank 32, and liquid distribution pipes 33. The liquid distribution storage tray 31 is located at the upper end of the evaporation plate mechanism 21 and connected to the evaporation plate mechanism 21. The liquid distribution storage tray 31 is used to receive the liquid fed in by the feeding pipe 43. The liquid distribution collection tank 32 is located above the liquid distribution storage tray 31, above the open end of the liquid distribution storage tray 31, and connected to the feeding pipe 43. The liquid distribution collection tank 32 is used to temporarily store and stabilize the supply flow rate, preventing the liquid film from being disturbed by instantaneous impact of the liquid. Multiple liquid distribution pipes 33 are connected to both sides of the liquid distribution collection tank 32. The multiple liquid distribution pipes 33 are arranged in an array along the length of the liquid distribution collection tank 32 and lead to different positions of the liquid distribution storage tray 31 to achieve uniform delivery of the liquid. The liquid distribution and storage tray 31 has multiple liquid distribution guide holes 34 at its bottom, which are distributed in a manner corresponding to the side wall of the evaporation plate mechanism 21 below. This allows the liquid to flow down the outer surface of the evaporation plate mechanism 21 directly through the liquid distribution guide holes 34 under the action of gravity, forming a uniform and continuous liquid film. During the operation of the evaporator, the liquid enters the distribution and collection tank 32 through the feeding pipe 43, flows into the liquid distribution storage tray 31 through multiple liquid distribution pipes 33 in sequence, and then falls through the liquid distribution guide holes 34 at the bottom. This ensures that the liquid film on the surface of each evaporation plate mechanism 21 is uniformly covered and the flow rate is stable, effectively preventing local dry walls, scaling, or gas overflow. This application improves the stability and uniformity of the liquid film through the graded liquid distribution structure, enhances the overall heat transfer efficiency of the evaporator, and facilitates the flow control of the subsequent evaporation process.

[0042] Specifically, such as Figure 3 As shown, the steam discharge device 5 of this application includes a demister mechanism 51 and a secondary steam discharge pipe 52. The demister mechanism 51 is disposed on the inner wall of the evaporator tank 1 and located above the liquid distribution device 3, and is fixedly connected to the evaporator tank 1. The demister mechanism 51 is used to perform primary liquid removal and demisting treatment on the secondary steam escaping during the evaporation process of the evaporation plate mechanism 21. When the secondary steam rises and passes through the demister mechanism 51, the liquid droplets, foam or mist impurities carried by it are captured under the action of gravity, inertia or surface tension, thereby achieving effective separation of steam and residual liquid. The treated secondary steam continues to flow upward and passes through the demister mechanism 52. The secondary steam discharge pipe 52, which is connected to the evaporator tank 1 above the demister mechanism 51, discharges the steam to the outside or downstream condensing equipment, achieving efficient collection of evaporation products. During the operation of the evaporator, the liquid film formed on the outer surface of the evaporator plate mechanism 21 continuously releases steam during the downward evaporation process. The steam is collected upward through the gap of the evaporator plate mechanism 21, passes through the demister mechanism 51 for efficient separation, and is discharged through the secondary steam discharge pipe 52, avoiding condensation pollution or energy loss caused by droplet entrainment. This application improves the quality of secondary steam, reduces the load on subsequent systems, avoids condensate back-mixing pollution, and is conducive to the continuous and stable operation of the evaporator.

[0043] The demister mechanism 51 is preferably a composite structure of multi-layer corrugated baffles and wire mesh, which can reduce the contamination of the subsequent condensation system by entrained liquid, reduce energy consumption and improve the quality of secondary steam.

[0044] The implementation principle of a plate falling film evaporator according to an embodiment of this application is as follows: The liquid evaporation plate device 2 is used to provide a liquid film evaporation area, and the liquid distribution device 3 is used to evenly distribute the fed liquid onto the outer surface of each evaporation plate mechanism 21; the liquid circulation device 4 is connected to the bottom of the evaporator tank 1 and extends above the liquid distribution device 3 to form a circulation loop, and the liquid circulation device 4 is used to return the incompletely evaporated liquid to the distribution end for continued evaporation; the steam discharge device 5 is used for secondary steam discharge, and the feed pipe 6 is used to replenish the original liquid into the evaporator tank 1; the thermal expansion coefficient of the descaling metal strip 24 in this application is greater than that of the evaporation plate mechanism 21. When the evaporator is heated and running, due to... Due to the thermal expansion difference between the descaling metal strip 24 and the evaporator plate mechanism 21, the descaling metal strip 24 generates a slight displacement or thermal expansion force in the vertical direction. Through top pressure or sliding action, it periodically disturbs the surface of the evaporator plate mechanism 21 in contact with the descaling metal strip 24, which can peel off the initially formed scale layer or prevent the scale layer from adhering firmly. During the heating or cooling stage, the descaling metal strip 24 returns to its original position as the temperature decreases, realizing a passive descaling process without external force. The descaling mechanism driven by the thermal expansion difference in this application can extend the operating cycle of the evaporator plate mechanism 21, improve the evaporation heat transfer efficiency, reduce the cleaning frequency and the operating cost of the evaporator. When the evaporator is running, heating steam flows in the heat exchange medium cavity 216 and transfers heat through the plate wall to the falling film liquid film formed outside the evaporator plate mechanism 21. The arrangement of the bulges 215 causes a nonlinear three-dimensional disturbance structure to form on the outer surface of the evaporator plate mechanism 21, thereby inducing local disturbance and flow velocity changes in the liquid film during the downward flow of the liquid, increasing the liquid film renewal frequency and heat transfer intensity, and helping to suppress local scaling and dry wall phenomena. This application enhances the effective heat exchange area and turbulence capability of the heat transfer surface, and improves the overall evaporation efficiency. The continuous transition area between the bulge structures is conducive to scale peeling and reduces scale adhesion, extending the evaporator operating cycle and reducing maintenance costs. The honeycomb array welding plus bulge molding structure of this application improves structural strength and thermal stability, and is suitable for long-term stable operation in high-intensity heat exchange environments. When the liquid material evaporates on the surface of the evaporation plate mechanism 21 during the operation of the evaporator, the descaling vibration mechanism 25 is activated simultaneously, causing the evaporation plate mechanism 21 to generate micro-vibrations within a certain frequency and amplitude range. On the one hand, this can disrupt the adhesion stability of the initial scale layer, causing the scale layer to be disturbed and peeled off before it solidifies. On the other hand, by coupling vibration with the descaling metal strip 24, a compound effect is formed between the descaling metal strip 24 and the evaporation plate mechanism 21, thereby enhancing the descaling effect. This application provides a solution for descaling without disassembly, which breaks the scale layer structure through vibration, improves the self-cleaning ability of the evaporation surface, extends the operating cycle of the evaporation plate, and reduces the frequency of manual maintenance and system downtime.

[0045] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A plate-type falling film evaporator, characterized in that, It includes an evaporator tank (1), a liquid evaporation plate device (2) inserted into the evaporator tank (1) and connected to the inner wall of the evaporator tank (1), a liquid distribution device (3) connected to the upper end of the liquid evaporation plate device (2), a liquid circulation device (4) connected to the bottom of the evaporator tank (1) and extending above the liquid distribution device (3), a steam discharge device (5) connected to the upper end of the evaporator tank (1) and used for steam discharge, and a feed pipe (6) connected to the evaporator tank (1); The liquid evaporation plate device (2) includes evaporation plate mechanisms (21) arranged in a horizontally spaced array, a fixed bracket (22) connected to the side edges of the plurality of evaporation plate mechanisms (21) and connected to the inner wall of the evaporator tank (1), a descaling connecting frame (23) connected to the outer wall of the evaporation plate mechanism (21), and a descaling metal strip (24) movably connected to the descaling connecting frame (23); the coefficient of thermal expansion of the descaling metal strip (24) is greater than the coefficient of thermal expansion of the evaporation plate mechanism (21).

2. A plate-type falling film evaporator according to claim 1, characterized in that, The evaporation plate mechanism (21) includes a first vertical plate (211), a second vertical plate (212) connected to the periphery of the first vertical plate (211), and a welding part (213) disposed on the first vertical plate (211) and the second vertical plate (212) and respectively used to connect the first vertical plate (211) and the second vertical plate (212); Multiple welding portions (213) are arranged in a honeycomb array along the outer surfaces of the first vertical plate (211) and the second vertical plate (212); after the welding portions (213) are welded, welding grooves (214) are formed at the location of the welding portions (213), and bulges (215) are formed on the non-welding areas between adjacent welding portions (213) on the first vertical plate (211) and the second vertical plate (212), and the bulges (215) are arranged in a matrix along the outer surfaces of the first vertical plate (211) and the second vertical plate (212); the welding portions (213), the first vertical plate (211) and the second vertical plate (212) surround each other to form a heat exchange medium cavity (216).

3. A plate-type falling film evaporator according to claim 2, characterized in that, The liquid evaporation plate device (2) further includes a steam inlet pipe (217) that is connected to the upper end of the plurality of evaporation plate mechanisms (21) and communicates with the heat exchange medium cavity (216), a condensation collection tank (218) that is connected to the lower end of the plurality of evaporation plate mechanisms (21) and communicates with the heat exchange medium cavity (216), a gas discharge pipe (219) that is connected to the upper side of the condensation collection tank (218) and extends to the outside of the evaporator tank (1), and a condensate discharge pipe (220) that is connected to the lower side of the condensation collection tank (218) and extends to the outside of the evaporator tank (1).

4. A plate-type falling film evaporator according to claim 2, characterized in that, The liquid evaporation plate device (2) also includes a descaling vibration mechanism (25) connected to the outer wall of the first vertical plate (211).

5. A plate-type falling film evaporator according to claim 1, characterized in that, The descaling connecting frame (23) includes a limiting clamp (231) connected to the outer wall of the evaporation plate mechanism (21) and used for the movable insertion of the descaling metal strip (24); a support base (232) connected to the outer wall of the evaporation plate mechanism (21) and pressed against the lower end of the descaling metal strip (24); and a limiting rod assembly (233) fixedly connected to the outer wall of the evaporation plate mechanism (21) and movably inserted into the upper end of the descaling metal strip (24); the limiting clamp (231) and the outer wall of the evaporation plate mechanism (21) are arranged to form an insertion gap (234), and the descaling metal strip (24) is movably inserted into the insertion gap (234) in the vertical direction; Multiple descaling connecting brackets (23) and descaling metal strips (24) are arranged in a spaced array along the width direction of the evaporation plate mechanism (21), and multiple limiting clamps (231) are arranged in a spaced array along the length direction of the evaporation plate mechanism (21).

6. A plate-type falling film evaporator according to claim 5, characterized in that, The width of the support base (232) gradually decreases from the middle to both ends.

7. A plate-type falling film evaporator according to claim 5, characterized in that, The upper end of the descaling metal strip (24) is provided with a strip-shaped clearance through hole (241) arranged along the length direction of the descaling metal strip (24); The limiting rod assembly (233) includes a limiting guide rod (2331) inserted into the strip-shaped clearance through hole (241) and connected at one end to the outer wall of the evaporation plate mechanism (21), and a blocking limiting member (2332) connected to the other end of the limiting guide rod (2331) and close to the outer wall of the descaling metal strip (24).

8. A plate-type falling film evaporator according to claim 1, characterized in that, The liquid circulation device (4) includes a discharge pipe (41) connected to the bottom of the evaporator tank (1) and communicating with the inside of the evaporator tank (1), a liquid circulation drive mechanism (42) connected to the discharge pipe (41), a feeding pipe (43) connected to the liquid circulation drive mechanism (42) and inserted into the inside of the evaporator tank (1), and a discharge pipe (44) connected to the feeding pipe (43) and located outside the evaporator tank (1); the feeding pipe (43) extends upward to above the liquid distribution device (3).

9. A plate-type falling film evaporator according to claim 8, characterized in that, The liquid distribution device (3) includes a liquid distribution storage tray (31) connected to the upper end of the evaporation plate mechanism (21), a liquid distribution collection tank (32) connected to the feeding pipe (43) and located above the opening end of the liquid distribution storage tray (31), and liquid distribution pipes (33) connected to both sides of the liquid distribution collection tank (32) and arranged in an array along the length direction of the liquid distribution collection tank (32); the bottom of the liquid distribution storage tray (31) is provided with a liquid distribution guide hole (34) located above the evaporation plate mechanism (21) and aligned with the side wall of the evaporation plate mechanism (21).

10. A plate-type falling film evaporator according to claim 1, characterized in that, The steam discharge device (5) includes a demister mechanism (51) connected to the inner wall of the evaporator tank (1) and located above the liquid distribution device (3), and a secondary steam discharge pipe (52) connected to the evaporator tank (1) and located above the demister mechanism (51).

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