Self-heating multi-effect evaporation device

Abstract

The invention relates to a self-heating multi-effect evaporation device, and belongs to the technical field of multi-effect evaporation, a first-effect medium circulation pipeline is arranged on a first-effect flash evaporation unit, other-effect flash evaporation units are connected in series through pipelines, a medium outlet of a last-effect flash evaporation unit is connected with a medium inlet of a heat exchange unit located at the second last effect, and a medium outlet of the heat exchange unit located at the second last effect is connected with a medium outlet of the heat exchange unit. The tube passes of the multiple heat exchange units are connected in series, a medium outlet of the heat exchange unit located at the first effect is connected with a medium inlet of the flash evaporation unit located at the second first effect through a pipeline, and a cooling circulation pipeline is arranged on the heat exchange unit located at the last effect. Complex high-pollution waste heat is recycled to serve as a driving heat source, the purposes of saving energy, reducing carbon, reducing energy consumption and reducing operation cost are achieved, meanwhile, an equivalent flash evaporation self-heating mode is adopted, multi-stage series heating and multi-stage flash evaporation are achieved, complete separation of waste water heating and flash evaporation is achieved, and the problems that a steam pipeline is large, and the pipeline trend is complex are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of multi-effect evaporation, and in particular relates to a self-heating multi-effect evaporation device. Background Art

[0002] The concentration of materials and high-salt wastewater is a key link widely used or essential in industrial production, and plays an indispensable role in many industries such as metallurgy, papermaking, electric power, and chemical industry. However, the traditional processes for concentrating materials and high-salt wastewater generally have the problem of high energy consumption. Most of these processes rely on external heat sources such as steam and electric energy to achieve the evaporation and concentration of water in the materials. The huge energy consumption not only increases the production cost of enterprises, but also makes enterprises face the risk of production restriction when the energy supply is tight.

[0003] On the other hand, during the industrial production process, a large amount of precious energy is consumed, and the industrial waste heat generated after a large amount of energy consumption often has problems such as complex heat medium components and low heat grade, making it difficult to recycle.

[0004] Taking the desulfurization system of coal-fired boilers as an example, most of the desulfurization processes adopted by coal-fired units in power plants or heating companies in China are wet desulfurization at present. During the wet desulfurization process, the desulfurization slurry is sprayed to fully contact with the flue gas. While reacting and desulfurizing, the heat in the flue gas is continuously absorbed by the desulfurization slurry, keeping the slurry temperature at 40 - 60°C. In the vast majority of coal-fired units, this part of the heat is not effectively utilized and wasted; in addition, during the operation of the wet desulfurization system, due to problems such as continuous reaction of the slurry and enrichment of chloride ions, a certain amount of desulfurization waste liquid needs to be regularly discharged from the desulfurization system. The desulfurization waste liquid belongs to high-salt wastewater, which is difficult to treat. The currently commonly used desulfurization wastewater treatment scheme is to consume a large amount of electric energy or clean steam as the driving energy for wastewater concentration, resulting in a large amount of energy and economic waste.

[0005] Taking the alkali recovery system of a pulp and paper mill as another example, the alkali recovery system of a pulp and paper mill is achieved by concentrating the pulping black liquor and then burning it in an alkali recovery boiler. The alkali recovery boiler uses black liquor with a concentration of more than 80% as fuel, and the steam generated by combustion is used for power generation and process use. At the same time, the flue gas generated by the boiler combustion carries a large amount of waste heat, which is wasted by being directly discharged; at present, most of the black liquor concentration is achieved by using a multi-effect evaporation process with medium and high-pressure steam as the heat source, resulting in a large amount of energy consumption and economic waste.

[0006] The distance between the heat source of the existing multi-effect evaporation and the heat-using system is too long. In a complex factory, pipelines need to be laid to introduce the heat source, which increases the construction difficulty and pipeline cost, and at the same time, the waste heat utilization rate is low. Summary of the Invention

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A self-heating multi-effect evaporation device includes: a plurality of flash units and a plurality of heat exchange units. The steam exhausted from the flash units provides heat sources for their equivalent heat exchange units. A first-effect medium circulation pipeline is provided on the flash unit located in the first effect, and the flash units of the remaining effects are connected in series through pipelines. The medium outlet of the flash unit located in the last effect is connected to the medium inlet of the heat exchange unit located in the second last effect. The tube sides of the plurality of heat exchange units are connected in series. The medium outlet of the heat exchange unit located in the first effect is connected to the medium inlet of the flash unit located in the second first effect through a pipeline. A cooling circulation pipeline is provided on the heat exchange unit located in the last effect. A pipeline for the medium to be heated is provided on the flash unit of any effect except the first effect or on the tube side of the heat exchange unit of any effect except the first and last effects.

[0008] Further, a multi-stage pressure-dividing unit for vacuum treatment of the flash unit is connected to the shell side of the heat exchange unit.

[0009] Further, a vacuum pump group for vacuum treatment of the flash unit is provided on the heat exchange unit.

[0010] Further, the multi-stage pressure-dividing unit includes: a water injection pressure divider. The shell side of the heat exchange unit is connected to a vacuum port provided on the water injection pressure divider for vacuum pumping through a pipeline.

[0011] Further, a pressure-dividing orifice plate is fixedly provided in the steam-water mixing chamber of the water injection pressure divider.

[0012] Further, when the medium in the flash unit located in the first effect is the same as the medium in the flash units of other effects, the outlet gas ports of the pressure-dividing liquid downcomers of the plurality of water injection pressure dividers are all placed below the liquid medium level in the first liquid seal box. A first air extraction port for air extraction is provided on the first liquid seal box.

[0013] Further, when the medium in the flash unit located in the first effect is different from the medium in the flash units of other effects, the outlet gas port of the pressure-dividing liquid downcomer of the water injection pressure divider connected to the shell side of the heat exchange unit located in the first effect is placed below the liquid medium level in the second liquid seal box, and the outlet gas ports of the pressure-dividing liquid downcomers of the water injection pressure dividers connected to the shell sides of the heat exchange units of the remaining effects are placed below the liquid medium level in the first liquid seal box. A first air extraction port for air extraction is provided on the first liquid seal box.

[0014] Further, a second air extraction port is provided on the second liquid seal box or the second liquid seal box is communicated with the first liquid seal box through a common gas pipeline.

[0015] Further, the distance between the outlet of the pressure-dividing submersible pipe of the water injection pressure divider and the liquid medium level in the first liquid seal box is proportional to the vacuum pressure at the vacuum port.

[0016] Further, a pressure-dividing orifice plate is slidably arranged in the steam-water mixing chamber of the water injection pressure divider. An expansion submersible pipe is slidably sleeved on the pressure-dividing submersible pipe. The expansion submersible pipe is connected to the pressure-dividing submersible pipe through a tension spring, and the expansion submersible pipe is connected to the pressure-dividing orifice plate through a connecting rod.

[0017] Further, the heat exchange unit of the first effect conveys the condensed water to the second condensed water tank through a pipeline, and the heat exchange units of the other effects convey the condensed water to the first condensed water tank through a pipeline.

[0018] Further, the heat exchange unit conveys the condensed water to the first liquid seal box or the first condensed water tank through a pipeline.

[0019] Further, the heat exchange unit of the first effect conveys the condensed water to the second liquid seal box or the second condensed water tank through a pipeline, and the heat exchange units of the other effects convey the condensed water to the first liquid seal box or the first condensed water tank through a pipeline.

[0020] Further, a first liquid supply pipeline is arranged between the second condensed water tank and the second liquid seal box, and a second liquid supply pipeline is arranged between the first liquid seal box and the first condensed water tank.

[0021] Further, a second liquid supply pipeline is arranged between the first liquid seal box and the first condensed water tank.

[0022] Further, a liquid inlet pipe is connected to the medium inlet of the variable-diameter water injection nozzle of the water injection pressure divider.

[0023] Further, a first drain pipeline and a first water inlet pipeline are arranged on the first liquid seal box.

[0024] Further, a first circulation pipeline is arranged between the liquid inlet pipe and the first drain pipeline.

[0025] Further, a second drain pipeline and a second water inlet pipeline are arranged on the second liquid seal box.

[0026] Further, a second circulation pipeline is arranged between the liquid inlet pipe and the second drain pipeline.

[0027] Further, the first air extraction port is connected to a common gas storage barrel through a pipeline, and a common air extraction pump group is arranged on the common gas storage barrel.

[0028] Further, the first air extraction port is connected to a common air storage barrel through a pipeline. A common air extraction pump group is arranged on the common air storage barrel. A second air extraction port for air extraction is arranged on the second liquid seal box, and the second air extraction port is connected to the common air storage barrel through a pipeline.

[0029] Further, regulating valves are arranged on the liquid inlet pipe and the pipeline of the vacuum port.

[0030] Advantages of the present invention: This application uses the recovered complex and highly polluted waste heat as the driving heat source to achieve energy conservation and carbon reduction, reduce energy consumption, and lower the operating cost. At the same time, the equivalent flash evaporation self-heating method is adopted to achieve multi-stage series heating, then multi-stage flash evaporation, and complete separation of wastewater heating and flash evaporation, solving problems such as a huge steam pipeline and complex pipeline routing. It also solves the problem of local over-boiling and scaling on the heat exchanger caused by simultaneous heating and evaporation. The waste heat extraction drives heating, flash evaporation concentration self-heating, and flash evaporation concentration cooling integration. Each working unit can be longitudinally arranged, saving floor space. Through the combination of various forms of vacuum devices, the low-temperature waste heat high-vacuum phase change recovery and ultra-low temperature material flash evaporation concentration generated in this process section are realized, while solving the problems of waste of waste heat resources in this process section and long-distance transportation of high-quality clean energy. The concentrated medium is heated in series in each flash evaporation unit, and only one material circulation pump is needed to realize the circulating heating and flash evaporation of the material, reducing the number of rotating equipment, lowering the system failure rate, and saving energy consumption. Description of the drawings

[0031] Figure 1 is the system diagram of Embodiment 1 of the present invention; Figure 2 is the system diagram of Embodiment 2, Method 1 of the present invention; Figure 3 is the system diagram of Embodiment 2, Method 2 of the present invention; Figure 4 is the system diagram of Embodiment 3, Method 1 of the present invention; Figure 5 is the system diagram of Embodiment 3, Method 2 of the present invention; Figure 6 is the structural schematic diagram of Embodiment 4 of the present invention. Description of the reference numerals

[0032] Among them, there are a flash evaporation unit 100, a heat exchange unit 200, a first-stage medium circulation pipeline 300, a cooling circulation pipeline 400, a multi-stage pressure dividing unit 500, a water jet pressure divider 510, a vacuum port 512, a pressure dividing liquid pipe 513, a steam-water mixing chamber 514, a pressure dividing orifice plate 515, a water jet variable-diameter nozzle 516, a telescopic lower pipe 517, a tension spring 518, a connecting rod 519, a first liquid seal box 520, a first drainage pipeline 521, a first water inlet pipeline 522, a first circulation pipeline 523, a first air extraction port 524, a second liquid seal box 530, a second drainage pipeline 531, a second water inlet pipeline 532, a second circulation pipeline 533, a second air extraction port 534, a first liquid replenishing pipeline 540, a second liquid replenishing pipeline 550, a medium-to-be-heated pipeline 600, a vacuum pump group 700, a first condensate water tank 800, a second condensate water tank 900, a liquid inlet pipe 1000, a common gas storage barrel 1100, a common air extraction pump group 1200, a common gas pipeline 1300, and a regulating valve 1400. Detailed implementation manners

[0033] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0034] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0035] The present invention will be further described below in conjunction with embodiments and drawings: Embodiment 1: As Figure 1As shown in the figure, a self-heating multi-effect evaporation device includes: a plurality of flash units 100 and a plurality of heat exchange units 200. The steam exhausted from the flash units 100 provides heat sources for their equivalent heat exchange units 200. A first-effect medium circulation pipeline 300 is provided on the flash unit 100 at the first effect. The flash units 100 at the other effects are connected in series through pipelines. The medium outlet of the flash unit 100 at the last effect is connected to the medium inlet of the heat exchange unit 200 at the second-to-last effect. The tube passes of the plurality of heat exchange units 200 are connected in series. The medium outlet of the heat exchange unit 200 at the first effect is connected to the medium inlet of the flash unit 100 at the second effect through a pipeline. A cooling circulation pipeline 400 is provided on the heat exchange unit 200 at the last effect. A medium pipeline 600 to be heated is provided on the flash unit 100 at any effect except the first effect or on the tube pass of the heat exchange unit 200 at any effect except the first and last effects. A vacuum pump group 700 for vacuum treatment of the flash unit 100 is provided on the heat exchange unit 200. The heat exchange unit 200 at the first effect transports condensed water to a second condensed water tank 900 through a pipeline, and the heat exchange units 200 at the other effects transport condensed water to a first condensed water tank 800 through a pipeline.

[0036] Among them, the flash unit 100 and the heat exchange unit 200 can be of an integral structure or can be connected through pipelines for transporting the exhausted steam. The "equivalent" in the statement that "the steam exhausted from the flash unit 100 provides heat sources for its equivalent heat exchange unit 200" means that there is a transmission relationship of exhausted steam medium between the flash unit and the heat exchange unit, that is, the two are in an equivalent relationship. The "heat exchange unit 200 at the first effect" refers to the heat exchange unit 200 of the flash unit where the medium to be concentrated first enters the heat exchange unit. The "flash unit 100 at the first effect" refers to the flash unit equivalent to the "heat exchange unit 200 at the first effect". The "flash unit 100 at the last effect" refers to the flash unit where the medium to be concentrated first enters the heat exchange unit from the flash unit. The "heat exchange unit 200 at the last effect" refers to the heat exchange unit equivalent to the "flash unit 100 at the last effect". A demister is provided in the flash unit 100 to remove the droplets carried in the exhausted steam. The plurality of flash units 100 can be arranged vertically, and the circulation of the medium between the plurality of flash units 100 is realized by the gravity of the liquid medium, thereby saving the use of liquid pumps and reducing costs. The heat exchange unit 200 is for steam-water heat exchange. The first-effect medium circulation pipeline 300 is a heat source circulation pipeline. The cooling circulation pipeline 400 provides a cold source for the heat exchange unit 200 at the last effect, dissipates the remaining heat energy of the system, and ensures the heat balance of the system. The vacuum pump group 700 can adopt a combination of a roots pump and a water ring pump or other types of vacuum pump groups that can meet the requirements.

[0037] This application recovers complex and highly polluted waste heat as the driving heat source to achieve energy conservation and carbon reduction, reduce energy consumption, and lower operating costs. At the same time, it adopts the equivalent flash self-heating method to achieve multi-stage series heating, then multi-stage flashing, and complete separation of wastewater heating and flashing, solving problems such as huge steam pipelines and complex pipeline routing. It also solves the problem of local over-boiling and scaling on the heat exchanger surface caused by simultaneous heating and evaporation. The waste heat extraction, driving heating, flash evaporation concentration self-heating, and flash evaporation concentration cooling are integrated, and each working unit can be arranged longitudinally to save floor space. Through the combination of various forms of vacuum devices, the low-temperature waste heat high-vacuum phase change recovery and ultra-low-temperature material flash evaporation concentration generated in this process section are achieved, while solving the problems of waste of waste heat resources and long-distance transportation of high-quality clean energy in this process section. The concentrated medium is heated in series in each flash unit, and only one material circulation pump is needed to achieve the cyclic heating and flashing of the material, reducing the number of rotating equipment, lowering the system failure rate, and saving energy consumption.

[0038] Comparative example: Technical comparison items 5-effect self-heating evaporation 5-effect multi-effect evaporation Floor area 15-20㎡ 80-100㎡ Number of flash evaporation material circulation pumps 1 unit 5 units Inter-effect connecting pipelines Below 0.5 m between effects At least 10 m or more connecting pipelines between each effect Evaporation-condensation inter-effect connecting pipelines No pipelines More than 2 meters Example 2: As Figure 2 and Figure 3As shown, on the basis of Embodiment 1, the vacuum pump group 700 is replaced with a multi-stage pressure-dividing unit 500. A multi-stage pressure-dividing unit 500 for performing vacuum treatment on the flash evaporation unit 100 is connected to the shell side of the heat exchange unit 200. The multi-stage pressure-dividing unit 500 includes: a water injection pressure divider 510, and the shell side of the heat exchange unit 200 is connected to a vacuum port 512 provided on the water injection pressure divider 510 for vacuum pumping through a pipeline. A pressure-dividing orifice plate 515 is fixedly arranged in a steam-water mixing chamber 514 inside the water injection pressure divider 510. When the media in the flash evaporation unit 100 at the first effect is the same as the media in the flash evaporation unit 100 at other effects, the air outlet of the pressure-dividing liquid downcomer 513 of multiple water injection pressure dividers 510 is placed below the liquid level of the liquid medium in the first liquid seal box 520, and a first air extraction port 524 for air extraction is provided on the first liquid seal box 520. The distance between the air outlet of the pressure-dividing liquid downcomer 513 of the water injection pressure divider 510 and the liquid level of the liquid medium in the first liquid seal box 520 is proportional to the vacuum pressure at the vacuum port 512. The medium inlet of the water injection variable-diameter nozzle 516 of the water injection pressure divider 510 is connected to a liquid inlet pipe 1000. Control valves 1400 are provided on both the liquid inlet pipe 1000 and the pipeline of the vacuum port 512. The first air extraction port 524 is connected to a common gas storage barrel 1100 through a pipeline, and a common air extraction pump group 1200 is provided on the common gas storage barrel 1100. The heat exchange unit 200 at the first effect transports condensed water to a second condensed water tank 900 through a pipeline, and the heat exchange unit 200 at other effects transports condensed water to a first condensed water tank 800 through a pipeline. When the media in the flash evaporation unit 100 at the first effect is the same as the media in the flash evaporation unit 100 at other effects, all the heat exchange units 200 transport condensed water to the first liquid seal box 520 or the first condensed water tank 800 through a pipeline, and a second liquid supplement pipeline 550 is provided between the first liquid seal box 520 and the first condensed water tank 800. A first drainage pipeline 521 and a first water inlet pipeline 522 are provided on the first liquid seal box 520. A first circulation pipeline 523 is provided between the liquid inlet pipe 1000 and the first drainage pipeline 521.

[0039] Among them, the water injection pressure divider can be called an ejector or a jet injector. The first liquid seal box 520 is a closed box, with a certain height of liquid inside for liquid sealing. The vacuum port 512 is connected to the heat exchange unit 200 through a pipeline to create a vacuum environment for the flash evaporation unit 100. The pressure dividing orifice plate 515 is a plate-like structure with multiple pressure dividing holes. The conveying pressure dividing holes are trumpet-shaped, and the large holes of the pressure dividing holes face the water injection variable diameter nozzle 516. The plate-like structure makes the pressure distribution uniform when the fluid passes through, avoiding flow instability caused by abnormal local resistance. The large hole inlet of the trumpet-shaped hole efficiently guides the fluid, and through the tapered structure, it accelerates to form a high-speed jet, significantly improving the pressure dividing efficiency. The high-speed jet enhances the medium turbulence in the steam-water mixing chamber 514, promotes full gas-liquid mixing, and improves the heat exchange efficiency. At the same time, the negative pressure area formed behind the orifice plate directly acts on the vacuum port 512, strengthening the air extraction ability of the flash evaporation unit 100 and maintaining a stable vacuum environment. In addition, the uniform pressure distribution, efficient pressure dividing and mixing, and stable vacuum treatment jointly ensure the operation stability of the system, reduce the risk of failures caused by local abnormalities, and ultimately achieve the high-efficiency energy saving and reliable operation of the multi-effect evaporation system. The common gas storage barrel 1100 is used to temporarily store the non-condensable gas discharged from the system, enabling the vacuum pumping system to operate intermittently. For the vacuum environment formation method, after the system is started, the air in the gas storage barrel 1100 is first discharged by the vacuum pump group. A vacuum environment is formed in the gas storage barrel, creating a pressure difference between the gas storage barrel and the system. The vacuum pump group reduces the frequency or pauses. Under the action of the pressure difference, the non-condensable gas discharged from the system continuously enters the gas storage barrel. When the pressure in the gas storage barrel reaches the set value, the vacuum pump group starts pumping again, achieving the purpose of saving the operation energy consumption of the vacuum pump group and stabilizing the system pressure.

[0040] In this application, by placing multiple said water injection pressure dividers 510 in the same first liquid seal box 520, connecting the common gas storage barrel 1100 through the first air extraction port 524, and using a common air extraction pump group 1200 to perform vacuum treatment on multiple vacuum chambers, the investment in vacuum pumps is saved, thereby achieving cost savings. At the same time, this application is provided with a regulating valve 1400 for regulating the liquid inlet flow rate and the air extraction flow rate of the vacuum port 512, thereby regulating the vacuum pressure of the components connected to the vacuum port 512. At the same time, the distance between the outlet of the pressure dividing liquid downcomer 513 and the liquid medium liquid level in the first liquid seal box 520 is set in direct proportion to the vacuum pressure at the vacuum port 512, which can prevent adjacent said water injection pressure dividers 510 from forming a vacuum channel, thereby destroying the vacuum pressure in the vacuum chambers connected to each other, further improving the system stability, achieving differential pressure grading under ultra-high vacuum and ultimate vacuum, and at the same time enabling a group of vacuum equipment to be shared by large temperature difference flash evaporation units. At the same time, through the action of ejector air extraction, the air extraction load of the vacuum pump can be greatly reduced, and the energy consumption of the air extraction pump group can be reduced.

[0041] Example 3, as Figure 4 and Figure 5As shown, the difference from Embodiment 2 is that when the medium in the flash evaporation unit 100 at the first effect is different from the medium in the flash evaporation units 100 at other effects, the air outlet of the pressure-dividing liquid downcomer 513 of the water injection pressure divider 510 connected to the shell side of the heat exchange unit 200 at the first effect is placed below the liquid medium level in the second liquid seal box 530, and the air outlet of the pressure-dividing liquid downcomer 513 of the water injection pressure divider 510 connected to the shell side of the heat exchange units 200 at the remaining effects is placed below the liquid medium level in the first liquid seal box 520. A first air extraction port 524 for air extraction is provided on the first liquid seal box 520. A second air extraction port 534 is provided on the second liquid seal box 530 or the second liquid seal box 530 is communicated with the first liquid seal box 520 through a common gas pipeline 1300. The first air extraction port 524 is connected to a common gas storage tank 1100 through a pipeline. A common air extraction pump group 1200 is provided on the common gas storage tank 1100. A second air extraction port 534 for air extraction is provided on the second liquid seal box 530. The second air extraction port 534 is connected to the common gas storage tank 1100 through a pipeline. The heat exchange unit 200 at the first effect transports condensed water to the second condensed water tank 900 through a pipeline, and the heat exchange units 200 at the remaining effects transport condensed water to the first condensed water tank 800 through a pipeline. The heat exchange unit 200 at the first effect transports condensed water to the second liquid seal box 530 or the second condensed water tank 900 through a pipeline, and the heat exchange units 200 at the remaining effects transport condensed water to the first liquid seal box 520 or the first condensed water tank 800 through a pipeline. A first liquid replenishment pipeline 540 is provided between the second condensed water tank 900 and the second liquid seal box 530, and a second liquid replenishment pipeline 550 is provided between the first liquid seal box 520 and the first condensed water tank 800. A second liquid replenishment pipeline 550 is provided between the first liquid seal box 520 and the first condensed water tank 800. A second drainage pipeline 531 and a second water inlet pipeline 532 are provided on the second liquid seal box 530. A second circulation pipeline 533 is provided between the liquid inlet pipe 1000 and the second drainage pipeline 531.

[0042] Among them, the first liquid seal box 520 and the second liquid seal box 530 have the same structure, and the size depends on the situation. The second water inlet pipeline 532 is used to supplement the medium in the second liquid seal box 530. The second circulation pipeline 533 is used to connect the water injection pressure divider 510 with the second liquid seal box 530 to realize internal circulation, thereby improving efficiency.

[0043] This application considers the case where the medium in the flash unit 100 at the first effect is different from the medium in the flash unit 100 at other effects. At the same time, in order to utilize the condensed water generated by the heat exchange unit 200, a first liquid seal box 520 and a second liquid seal box 530 are provided. The condensed water generated by the heat exchange unit 200 at the first effect is transported into the first liquid seal box 520 for liquid sealing, and the condensed water generated by the heat exchange unit 200 at other effects is transported into the second liquid seal box 530 for liquid sealing, thereby effectively preventing the mutual influence of the water quality of the condensed water. At the same time, the second liquid seal box 530 and the first liquid seal box 520 are connected through a common gas pipeline 1300, and thus a common air extraction pump group 1200 can be shared, also meeting the condition of saving the pump group.

[0044] Example 4, as Figure 6 shown, different from Example 2 where the pressure-dividing orifice plate 515 is not fixedly installed in the steam-water mixing chamber 514, a pressure-dividing orifice plate 515 is slidably arranged in the steam-water mixing chamber 514 of the water injection pressure divider 510. A telescopic lower pipe 517 is slidably sleeved on the pressure-dividing liquid down pipe 513. The telescopic lower pipe 517 is connected to the pressure-dividing liquid down pipe 513 through a tension spring 518, and the telescopic lower pipe 517 is connected to the pressure-dividing orifice plate 515 through a connecting rod 519.

[0045] In Embodiment 4 of this application, the dynamic pressure-dividing adjustment structure of the water injection pressure divider 510 realizes the adaptive regulation of the hydrodynamic characteristics in the steam-water mixing chamber 514 through the linkage design of the sliding pressure-dividing orifice plate 515, the telescopic lower pipe 517 and the tension spring 518, significantly improving the comprehensive performance of the multi-effect evaporation system. This structure impacts the pressure-dividing orifice plate 515 through the high-speed jet of the water injection variable-diameter nozzle 516, enabling it to drive the telescopic lower pipe 517 to slide along the pressure-dividing liquid down pipe 513 through the connecting rod 519. Cooperating with the reverse restoring force of the tension spring 518, a dynamic pressure balance is achieved at the balance point of the impact force and the spring force, ensuring that the vacuum pressure at the vacuum port 512 is strictly proportional to the liquid seal depth, effectively solving the problem of vacuum instability caused by the fluctuation of working conditions for the traditional fixed orifice plate. This dynamic balance mechanism endows the system with the ability to adapt to all working conditions, and can automatically adjust the jet path and liquid seal height through the stroke change of the telescopic lower pipe 517, maintaining efficient operation within the range of 30% - 120% of the design load, breaking through the sensitivity limit of traditional devices to changes in working conditions.

[0046] On this basis, by precisely controlling the vacuum gradient of each flash unit 100, the vacuum degree of the last-effect flash unit is increased by 15% - 20%, significantly reducing the boiling point of the material and improving the flash efficiency; meanwhile, the dynamic compensation effect of the pressure-dividing orifice plate 515 reduces the suction load fluctuation of the shared air extraction pump group 1200 by more than 30%. Combined with the coordinated control of the regulating valve 1400, the energy consumption of the vacuum pump group is reduced by 25% - 30%, greatly improving the energy efficiency ratio of the system. In terms of equipment maintenance, the flexible sliding structure of the telescopic lower pipe 517 effectively buffers the jet impact, reducing the cavitation incidence rate by more than 80%. Moreover, the reciprocating motion of the sliding orifice plate can automatically remove scale impurities, extending the maintenance cycle by more than twice. This design also has the advantage of modular integration. By using standardized components, the number of non-standard parts is reduced by 30%, reducing manufacturing and inventory costs. At the same time, the pre-tightening force of the tension spring 518 can be adjusted externally, enhancing the engineering adaptability.

[0047] In addition, the rigid connection of the connecting rod 519 ensures the synchronous movement of the orifice plate and the lower pipe, avoiding the hysteresis jamming problem of flexible connection. Combined with the overload protection characteristics of the spring, the equipment failure rate is reduced by more than 40%. This structure does not require an additional power source and is driven by the energy of the fluid itself for regulation, further enhancing the intrinsic safety. In summary, the dynamic pressure-dividing regulation technology of Embodiment 4 realizes real-time self-correction of hydrodynamic parameters through mechanical structure innovation, achieving breakthrough improvements in vacuum stability, energy consumption efficiency, operating condition adaptability, and equipment reliability, providing key technical support for the efficient and stable operation of the multi-effect evaporation system in complex industrial environments.

[0048] The above has described the embodiments of the present invention in detail, but the content described is only the preferred embodiments of the present invention and cannot be considered as limiting the scope of implementation of the present invention. Any equal changes and improvements made according to the scope of the present invention application shall still fall within the scope covered by the patent of the present invention.

Claims

1. A self-heating multi-effect evaporation device, characterized in that, Including: Multiple flash units (100) and multiple heat exchange units (200), the steam exhausted from the flash units (100) provides heat sources for their equivalent heat exchange units (200). A first-effect medium circulation pipeline (300) is provided on the flash unit (100) at the first effect, and the flash units (100) of the remaining effects are connected in series through pipelines. The medium outlet of the flash unit (100) at the last effect is connected to the medium inlet of the heat exchange unit (200) at the second last effect, and the tube sides of the multiple heat exchange units (200) are connected in series. The medium outlet of the heat exchange unit (200) at the first effect is connected to the medium inlet of the flash unit (100) at the second first effect through a pipeline. A cooling circulation pipeline (400) is provided on the heat exchange unit (200) at the last effect. A medium pipeline to be heated (600) is provided on the flash unit (100) of any effect except the first effect or on the tube side of the heat exchange unit (200) of any effect except the first effect and the last effect.

2. The self-heating multi-effect evaporation device according to claim 1, characterized in that, A multi-stage pressure reducing unit (500) for vacuum treatment of the flash unit (100) is connected to the shell side of the heat exchange unit (200).

3. The self-heating multi-effect evaporation device according to claim 1, wherein A vacuum pump group (700) for vacuum treatment of the flash unit (100) is provided on the heat exchange unit (200).

4. The self-heating multi-effect evaporation device according to claim 2, wherein The multi-stage pressure reducing unit (500) includes: a water injection pressure reducer (510), and the shell side of the heat exchange unit (200) is connected to a vacuum port (512) provided on the water injection pressure reducer (510) for vacuum pumping through a pipeline.

5. The self-heating multi-effect evaporation device according to claim 4, characterized in that, A pressure reducing orifice plate (515) is fixedly provided in the steam-water mixing chamber (514) inside the water injection pressure reducer (510).

6. The self-heating multi-effect evaporation device according to claim 4, wherein When the medium in the flash unit (100) at the first effect is the same as the medium in the flash units (100) of other effects, the outlet gas ports of the pressure reducing liquid pipes (513) of the multiple water injection pressure reducers (510) are all placed below the liquid medium level in the first liquid seal box (520), and a first air extraction port (524) for air extraction is provided on the first liquid seal box (520).

7. A self-heating multi-effect evaporation device according to claim 4, characterized in that, When the medium in the flash unit (100) at the first effect is different from the medium in the flash units (100) of other effects, the outlet gas port of the pressure reducing liquid pipe (513) of the water injection pressure reducer (510) connected to the shell side of the heat exchange unit (200) at the first effect is placed below the liquid medium level in the second liquid seal box (530), and the outlet gas ports of the pressure reducing liquid pipes (513) of the water injection pressure reducers (510) connected to the shell sides of the heat exchange units (200) of the remaining effects are placed below the liquid medium level in the first liquid seal box (520). A first air extraction port (524) for air extraction is provided on the first liquid seal box (520).

8. A self-heating multi-effect evaporation device according to claim 7, characterized in that, A second air extraction port (534) is provided on the second liquid seal box (530) or the second liquid seal box (530) is communicated with the first liquid seal box (520) through a common gas pipeline (1300).

9. An auto-heating multi-effect evaporation device according to claim 6 or 7, characterized in that, The distance between the outlet of the pressure-dividing submersible pipe (513) of the water injection pressure divider (510) and the liquid medium level in the first liquid seal box (520) is proportional to the vacuum pressure at the vacuum port (512).

10. A self-heating multi-effect evaporation device according to claim 9, characterized in that, A pressure-dividing orifice plate (515) is slidably arranged in the steam-water mixing chamber (514) of the water injection pressure divider (510). An expansion submersible pipe (517) is slidably sleeved on the pressure-dividing submersible pipe (513). The expansion submersible pipe (517) is connected to the pressure-dividing submersible pipe (513) through a tension spring (518). The expansion submersible pipe (517) is connected to the pressure-dividing orifice plate (515) through a connecting rod (519).

11. A self-heating multi-effect evaporation device according to claim 3, characterized in that, The heat exchange unit (200) of the first effect transports condensed water to the second condensed water tank (900) through a pipeline, and the heat exchange units (200) of the other effects transport condensed water to the first condensed water tank (800) through a pipeline.

12. A self-heating multi-effect evaporation device according to claim 6, characterized in that, The heat exchange unit (200) transports condensed water to the first liquid seal box (520) or the first condensed water tank (800) through a pipeline.

13. A self-heating multi-effect evaporation device according to claim 7, characterized in that, The heat exchange unit (200) of the first effect transports condensed water to the second liquid seal box (530) or the second condensed water tank (900) through a pipeline, and the heat exchange units (200) of the other effects transport condensed water to the first liquid seal box (520) or the first condensed water tank (800) through a pipeline.

14. A self-heating multi-effect evaporation device according to claim 13, characterized in that, A first liquid supplement pipeline (540) is arranged between the second condensed water tank (900) and the second liquid seal box (530), and a second liquid supplement pipeline (550) is arranged between the first liquid seal box (520) and the first condensed water tank (800).

15. A self-heating multi-effect evaporation device according to claim 12, characterized in that, A second liquid supplement pipeline (550) is arranged between the first liquid seal box (520) and the first condensed water tank (800).

16. A self-heating multi-effect evaporation device according to claim 4, characterized in that, The medium inlet of the water injection variable-diameter nozzle (516) of the water injection pressure divider (510) is connected with a liquid inlet pipe (1000).

17. A self-heating multi-effect evaporation device according to claim 15, characterized in that, A first drain pipeline (521) and a first water inlet pipeline (522) are arranged on the first liquid seal box (520).

18. A self-heating multi-effect evaporation device according to claim 17, wherein, A first circulation pipeline (523) is arranged between the liquid inlet pipe (1000) and the first drain pipeline (521).

19. A self-heating multi-effect evaporation device according to claim 13, characterized in that, A second drain pipeline (531) and a second water inlet pipeline (532) are arranged on the second liquid seal box (530).

20. A self-heating multi-effect evaporation device according to claim 19, characterized in that, A second circulation pipeline (533) is arranged between the liquid inlet pipe (1000) and the second drain pipeline (531).

21. The self-heating multi-effect evaporation device according to claim 6, characterized in that, The first air extraction port (524) is connected with a common gas storage barrel (1100) through a pipeline, and a common air extraction pump group (1200) is arranged on the common gas storage barrel (1100).

22. The self-heating multi-effect evaporation device according to claim 7, characterized in that, The first air extraction port (524) is connected with a common gas storage barrel (1100) through a pipeline, and a common air extraction pump group (1200) is arranged on the common gas storage barrel (1100). A second air extraction port (534) for air extraction is arranged on the second liquid seal box (530), and the second air extraction port (534) is connected with the common gas storage barrel (1100) through a pipeline.

23. A self-heating multi-effect evaporation device according to claim 16, wherein Regulating valves (1400) are arranged on both the liquid inlet pipe (1000) and the pipeline of the vacuum port (512).

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