Multi-effect evaporative crystallization device for liquid hazardous wastes

Abstract

The utility model discloses a multi-effect evaporative crystallization device for liquid hazardous wastes, which comprises a feed buffer tank and a plurality of evaporation reaction tanks, and a discharge port of the feed buffer tank is respectively connected with liquid inlets of the evaporation reaction tanks through a feed pump; a feeding stirring mechanism is arranged in the feeding buffer tank, and the feeding buffer tank is used for homogenizing and storing liquid to be treated; a metal wire mesh corrugated packing layer is arranged at the top of the interior of the evaporation reaction tank, and a discharge port is formed in the bottom of the interior of the evaporation reaction tank; a frame type stirring mechanism and an anchor type stirring mechanism are arranged on the upper side and the lower side in the evaporation reaction tank respectively, a guide cylinder is arranged on the outer side of the frame type stirring mechanism, and a plurality of baffle plates are arranged at the bottom of the metal wire mesh corrugated packing layer located above the guide cylinder. On one hand, a high-efficiency evaporation area is formed through the guide cylinder, on the other hand, the heat and mass transfer effect is remarkably enhanced through the metal wire mesh corrugated packing layer and the baffle plates, finally, the overall evaporation and crystallization efficiency is cooperatively improved, and good practicability is achieved.

Description

Technical Field

[0001] This utility model belongs to the technical field of evaporation crystallization equipment, specifically relating to a multi-effect evaporation crystallization device for liquid hazardous waste. Background Technology

[0002] With industrial development, the amount of liquid hazardous waste generated is constantly increasing. However, liquid hazardous waste has a complex composition, containing toxic and harmful substances such as heavy metals and organic matter. If discharged without effective treatment, it will seriously pollute the environment and endanger the ecosystem and human health. Currently, traditional methods for treating liquid hazardous waste have the following limitations:

[0003] (1) Existing physical precipitation methods are ineffective at removing soluble harmful substances;

[0004] (2) Existing chemical treatment methods are prone to causing secondary pollution and are costly;

[0005] (3) Existing biological treatment methods have high requirements for treatment conditions and narrow applicability.

[0006] In evaporation technology, early single-effect evaporation had high energy consumption and cost, while multi-effect evaporation technology reduces energy consumption. For example, CN211912762U discloses a multi-effect evaporation device. This device includes N-stage evaporators and flash evaporators, where N≥3 and N is an integer. Each stage of evaporator includes an evaporation chamber and a heating chamber. The heating chamber in the Nth stage evaporator includes heating chamber I and heating chamber II connected in parallel. The condensate outlet of the first stage evaporator is directly connected to heating chamber I, or the condensate outlet of the first stage evaporator is connected to heating chamber I via the flash evaporator. When N=3, the condensate outlet of the second stage evaporator is connected to heating chamber II of the third stage evaporator via the flash evaporator. When N≥4, the condensate outlets of the second stage evaporator to the (N-2)th stage evaporator are respectively connected to the heating chamber of the (N-1)th stage evaporator via the flash evaporator, or connected to heating chamber II. By using the steam obtained from the flash evaporation of the high-temperature condensate to heat the final two-effect evaporators, the sensible heat of the high-temperature condensate can be fully utilized, saving energy. Simultaneously, the water vapor condensate and secondary steam condensate are separated, achieving separation of clean and dirty water. However, existing multi-effect evaporation devices still have the following problems:

[0007] 1) Liquid hazardous waste is prone to sedimentation and stratification in containers, affecting the stability of treatment. When existing evaporation equipment is in operation, the liquid needs to be continuously evaporated through a single-effect evaporator, double-effect evaporator, triple-effect evaporator or five-effect evaporator. During this process, as the liquid passes through each evaporator in turn, the concentration of the liquid gradually increases. After the liquid enters the conveying pipe and conveying pump between adjacent evaporators, crystals will form in the pipe due to the decrease in temperature, which will cause pipe blockage and system operation failure.

[0008] 2) The reaction tank has a poor structure, resulting in a short residence time for waste liquid and low evaporation efficiency. The existing evaporation equipment is a series-connected multi-effect evaporator that can only supply material in stages. When one of the evaporators fails, the entire equipment will be unable to work.

[0009] 3) The degree of automation is low, requiring frequent manual operation and monitoring, resulting in high labor costs and the risk of human error affecting the security and stability of the process.

[0010] Therefore, the development of efficient, energy-saving, and highly automated liquid hazardous waste treatment equipment is of great practical significance and market demand. Utility Model Content

[0011] The purpose of this invention is to provide a multi-effect evaporation and crystallization device for liquid hazardous waste. It uses a feed buffer tank to homogenize and store the liquid to be treated, thereby accelerating the processing efficiency of the evaporation reaction tank. Furthermore, the overall evaporation and crystallization efficiency is improved synergistically through the metal wire mesh corrugated packing layer, frame-type stirring mechanism, anchor-type stirring mechanism, guide tube, and baffle plate inside the evaporation reaction tank.

[0012] This utility model is mainly achieved through the following technical solutions:

[0013] A multi-effect evaporation crystallization device for liquid hazardous waste includes a feed buffer tank and several evaporation reaction tanks. The outlet of the feed buffer tank is connected to the inlets of the several evaporation reaction tanks via feed pumps. The feed buffer tank is equipped with a feed stirring mechanism and is used for homogenizing and storing the liquid to be treated. A metal wire mesh corrugated packing layer is provided at the top of the evaporation reaction tank, and a discharge port is provided at the bottom. A frame-type stirring mechanism and an anchor-type stirring mechanism are respectively provided on the upper and lower sides of the evaporation reaction tank. A guide tube is provided on the outside of the frame-type stirring mechanism, and several baffles are provided at the bottom of the metal wire mesh corrugated packing layer above the guide tube. In this application, "several" refers to one or more, meaning it can include one feed buffer tank and one evaporation reaction tank.

[0014] To better realize this utility model, the anchor stirring mechanism further includes an anchor stirring motor and an anchor stirring blade. The anchor stirring motor is installed at the bottom of the evaporation reaction tank, and the drive end of the evaporation reaction tank extends into the evaporation reaction tank and is connected to the anchor stirring blade. An elastic scraper that is in close contact with the evaporation reaction tank is provided on the outer side of the anchor stirring blade along the length direction.

[0015] To better realize this utility model, the frame stirring mechanism further includes a frame stirring motor, a stirring shaft and frame stirring blades. The frame stirring motor is installed on the top of the evaporation reaction tank, and the drive end of the evaporation reaction tank extends into the evaporation reaction tank and is connected to the frame stirring blades through the stirring shaft; a guide tube is provided on the outer side of the frame stirring blades.

[0016] To better realize this utility model, the feed pump is further connected to the feed buffer tank and the evaporation reaction tank through the delivery pipe, and a static mixer is installed inside the delivery pipe near the evaporation reaction tank, and a magnetic float level gauge is installed on the delivery pipe near the feed pump.

[0017] To better realize this utility model, the top two sides of the feeding buffer tank are respectively provided with a feed inlet and a discharge outlet; the feeding stirring mechanism includes a feeding stirring motor and a stirrer, the feeding stirring motor is installed in the middle of the top of the feeding buffer tank, and the drive end of the feeding stirring motor extends into the feeding buffer tank and is connected to the stirrer.

[0018] To better realize this utility model, the outer side of the evaporation reaction tank is provided with a heat insulation layer, and the side wall of the evaporation reaction tank is provided with a steam inlet, and the bottom of the evaporation reaction tank is also provided with a drain outlet.

[0019] To better realize this utility model, a thermometer is further provided on the top of the evaporation reaction vessel, and several monitoring sensors are provided on the inner sidewall of the evaporation reaction vessel.

[0020] To better realize this utility model, it further includes a PLC, which is connected to the feed pump, the feed stirring mechanism, the frame stirring mechanism, the anchor stirring mechanism, the thermometer, and the monitoring sensor.

[0021] The beneficial effects of this utility model are as follows:

[0022] (1) This utility model forms a high-efficiency evaporation zone through a frame-type stirring mechanism, an anchor-type stirring mechanism, and a guide tube. On the other hand, it increases the contact time and opportunities between steam and waste liquid in the high-efficiency evaporation zone through a metal wire mesh corrugated packing layer and baffles, significantly enhancing the heat and mass transfer effect. Ultimately, it synergistically improves the overall evaporation and crystallization efficiency of the device, and has good practicality. Specifically, this utility model changes the fluid's path by using a guide tube, strengthens the direct shearing action of the blades on the fluid and forms a strong mixing zone, eliminates vortices, promotes full mixing of materials, and enhances mass and heat transfer. Then, in conjunction with the baffles above, the steam changes its flow direction multiple times during the ascent, increasing the contact time and opportunities with the waste liquid, enhancing the heat and mass transfer process, and accelerating the thermal utilization efficiency of thermal evaporation. Furthermore, this utility model can perform low-temperature evaporation at 45-65℃ under vacuum negative pressure (-90Kpa ~ -80Kpa) in the evaporation reaction tank, avoiding secondary pollution caused by high temperature, reducing the requirements for equipment materials, and improving the safety and environmental protection of the process.

[0023] (2) The evaporation reactor is heated by a steam jacket and is equipped with a frame-type stirring mechanism and an anchor-type stirring mechanism, along with a metal wire mesh corrugated packing layer, baffles, and a guide tube. The frame-type stirring mechanism and the anchor-type stirring mechanism ensure uniform mixing and heating of the materials, facilitating evaporation and slag discharge. The guide tube guides the material circulation, the baffles enhance the heat and mass transfer between steam and waste liquid, and the metal wire mesh corrugated packing layer increases the evaporation contact area, thus improving evaporation efficiency. This invention is based on PLC control and can achieve automated control of the entire process from feeding, evaporation, slag discharge to refeeding. Furthermore, the condensate generated by evaporation is collected and sent to a wastewater treatment plant for deep treatment to meet standards for reuse, realizing the recycling of water resources. The treated solid slag is automatically discharged and can be reasonably treated according to actual conditions, reducing waste discharge and conforming to the concepts of environmental protection and sustainable development. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the multi-effect evaporation and crystallization treatment device for liquid hazardous waste of this utility model;

[0025] Figure 2 This is a schematic diagram of the frame-type stirring mechanism;

[0026] Figure 3 This is a schematic diagram of the anchor-type stirring mechanism.

[0027] Wherein: 10-feed buffer tank, 101-feed inlet, 102-feed mixing motor, 103-mixer, 104-discharge outlet.

[0028] 20-Feed pump,

[0029] 30-Transfer pipe, 301-Magnetic level gauge, 302-Static mixer

[0030] 40 - Automated Control System

[0031] 50-Evaporation reactor, 501-Liquid inlet, 502-Thermometer, 503-Monitoring sensor, 504-Frame stirring mechanism, 5041-Guide tube, 5042-Frame stirring blade, 5043-Stirring shaft, 5044-Frame stirring motor, 505-Anchor stirring mechanism, 5051-Anchor stirring blade, 5052-Elastic scraper, 5053-Anchor stirring motor, 506-Metal wire mesh corrugated packing layer, 507-Baffle plate, 508-Steam inlet, 509-Insulation layer, 510-Discharge port, 511-Drain outlet. Detailed Implementation

[0032] Example 1:

[0033] A multi-effect evaporation and crystallization device for liquid hazardous waste, such as Figure 1 As shown, it includes a feed buffer tank 10, an evaporation reactor 50, and an automated control system 40. The discharge port 104 of the feed buffer tank 10 is connected to the liquid inlet 501 of the evaporation reactor 50 via a feed pump 20. The feed buffer tank 10 is equipped with a feed stirring mechanism inside, and the feed buffer tank 10 is used to homogenize and store the liquid to be processed; the upper and lower sides of the evaporation reaction tank 50 are respectively equipped with a frame stirring mechanism 504 and an anchor stirring mechanism 505, and the bottom of the evaporation reaction tank 50 is correspondingly equipped with a discharge port 510. The outer side of the anchor stirring blade 5051 of the anchor stirring mechanism 505 is equipped with an elastic scraper 5052 that is in close contact with the evaporation reaction tank 50 along the length direction; the top of the evaporation reaction tank 50 is equipped with a metal wire mesh corrugated packing layer 506, the outer side of the frame stirring mechanism 504 is equipped with a guide tube 5041, and the bottom of the metal wire mesh corrugated packing layer 506 above the guide tube 5041 is equipped with several baffles 507.

[0034] Preferably, the feed buffer tank 10 is cylindrical and made of corrosion-resistant stainless steel. The top of the feed buffer tank 10 is provided with a feed inlet 101 and a discharge outlet 104, and a feed stirring mechanism is installed inside the tank. The feed stirring mechanism includes a feed stirring motor 102 and a stirrer 103. For example, a variable-speed stirrer 103 is installed inside the feed buffer tank 10, and the stirrer 103 has inclined blades. After pretreatment to remove impurities, the liquid hazardous waste enters the tank. The feed stirring mechanism is activated, and the material is uniformly mixed by different speeds to prevent sedimentation and stratification, ensuring that the liquid hazardous waste entering subsequent treatment stages has a uniform and stable composition, thus improving the overall treatment effect and stability. The material inside the feed buffer tank 10 is transported to the evaporation reaction tank 50 through a conveying pipe 30.

[0035] Preferably, the evaporation reaction tank 50 is cylindrical, with a feed inlet 101 at the top and a discharge outlet 510 and a drain outlet 511 at the bottom. The evaporation reaction tank 50 is heated by a steam jacket, with the jacket made of metal. The outer wall of the evaporation reaction tank 50 is provided with a heat insulation layer 509 and a steam inlet 508, and the inner wall is provided with temperature, pressure and other monitoring sensors 503.

[0036] like Figures 1-3 As shown, the evaporation reactor 50 includes two stirring mechanisms—an anchor stirring mechanism 505 and a frame stirring mechanism 504. The anchor stirring mechanism 505 is located at the bottom of the reactor, near the discharge port 510. The anchor stirring mechanism 505 includes an anchor stirring motor 5053 and anchor stirring blades 5051. The anchor stirring motor 5053 is installed at the bottom of the evaporation reactor 50, and the drive end of the evaporation reactor 50 extends into the evaporation reactor 50 and is connected to the anchor stirring blades 5051. Elastic scrapers 5052 are installed on the scraper edge of the anchor stirring mechanism 505. These scrapers are made of corrosion-resistant and highly elastic materials such as silicone rubber. When the stirrer 103 rotates, the elastic scrapers 5052 can closely adhere to the bottom and wall of the reactor, promptly removing the attached solid slag and preventing its accumulation from affecting the stirring effect and heat transfer efficiency. The frame-type stirring mechanism 504 is installed in the middle of the reaction tank. The frame-type stirring mechanism 504 includes a frame-type stirring motor 5044, a stirring shaft 5043, and a frame-type stirring blade 5042. The frame-type stirring motor 5044 is installed on the top of the evaporation reaction tank 50, and the drive end of the evaporation reaction tank 50 extends into the evaporation reaction tank 50 and is connected to the frame-type stirring blade 5042 through the stirring shaft 5043. A guide tube 5041 is provided on the outer side of the frame-type stirring blade 5042.

[0037] Preferably, a baffle plate 507 is added below the metal wire mesh corrugated packing layer 506. The baffle plate 507 is made of stainless steel and is wavy. The height and spacing of its crests and troughs are optimized according to the size of the reaction tank and the evaporation characteristics of the waste liquid, so that the steam changes its flow direction multiple times during the rising process, increases the contact time and opportunity with the waste liquid, and strengthens the heat and mass transfer process.

[0038] The evaporation reaction tank 50 includes a guide tube 5041, which is arranged around the frame-type stirring mechanism 504. It is made of high-temperature resistant and corrosion-resistant polytetrafluoroethylene material. Its height and diameter are adapted to the reaction tank and the stirrer 103 to guide the material to form a specific circulating flow, so that the material flows more orderly during the stirring process, improves the stirring efficiency, and enhances the heat and mass transfer effect.

[0039] During operation, materials are fed into the evaporation reactor 50, and steam is introduced through the steam jacket for heating. Under a vacuum pressure of -90Kpa to -80Kpa and a steam temperature of 105-120℃, the temperature inside the reactor is maintained at 45-65℃ for low-temperature evaporation. Continuous stirring is maintained, with the anchor-type stirring mechanism 505 pushing the solid slag towards the discharge port 510. Elastic scrapers 5052 are installed on the edges of the anchor-type stirring blades 5051, allowing them to adhere closely to the bottom and walls of the reactor, promptly removing adhering solid slag and preventing its accumulation from affecting the stirring effect and heat transfer efficiency. The frame-type stirring mechanism 504 ensures uniform mixing and heating of the materials. The corrugated metal mesh packing layer 506 increases the contact area between the waste liquid and steam, enhancing heat and mass transfer, further improving evaporation efficiency and reducing energy consumption. The presence of the baffle plate 507 causes the steam to change its flow direction multiple times during its ascent, increasing the contact time and opportunities with the waste liquid, thus enhancing the heat and mass transfer process. The stirring mechanism improves evaporation efficiency and facilitates slag discharge.

[0040] Preferably, a static mixer 302 is installed inside the conveying pipe 30. The feed pump 20 is connected to the feed buffer tank 10 and the evaporation reaction tank 50 through the conveying pipe 30. The static mixer 302 is installed inside the conveying pipe 30 near the evaporation reaction tank 50, and a magnetic float level gauge 301 is installed on the conveying pipe 30 near the feed pump 20. The static mixer 302 uses high-efficiency mixing elements such as SK or SV type to further mix the liquid hazardous waste evenly during the conveying process and prevent component separation during the conveying process.

[0041] Preferably, the evaporation reactor 50 includes a high-precision monitoring sensor 503, which is disposed inside the evaporation reactor 50.

[0042] The automated control system 40 is existing technology and will not be described in detail here. The automated control system 40 uses a PLC as its core and combines it with a high-precision, intelligent monitoring sensor 503 to monitor parameters such as pressure, temperature, liquid level, and composition inside the reaction tank in real time. Through adaptive control and fuzzy control technology, it automatically adjusts steam flow rate, feed rate, etc., to improve processing efficiency and stability and reduce manual operation and human error.

[0043] Preferably, advanced monitoring sensor 503 technology is used to monitor the parameters of the evaporation reactor 50 in real time. Multiple monitoring sensors 503 are installed inside the evaporation reactor 50 to monitor various parameters within the reactor 50 in real time, including pressure, temperature, and liquid level. These monitoring sensors 503 can be high-precision, intelligent sensors with higher accuracy and stronger anti-interference capabilities. For example, a fiber optic monitoring sensor 503 (MS28-YS-1002) is used to measure temperature and pressure; a component monitoring sensor 503 (model: Alphasense H2S-AE) is used to monitor the concentration changes of hazardous substances in the liquid hazardous waste in real time, providing more comprehensive data support for subsequent treatment. The layout of the monitoring sensors 503 is further optimized by rationally distributing them according to the characteristics of temperature, pressure, and liquid level changes at different locations within the reactor. For example, monitoring sensors 503 are added near the steam inlet 508, around the agitator 103, and above the discharge port 510 to ensure more accurate acquisition of various information within the reactor.

[0044] Preferably, the automated control system 40 is based on a programmable logic controller (PLC), and is equipped with various monitoring sensors 503, such as pressure monitoring sensor 503, temperature monitoring sensor 503, and liquid level monitoring sensor 503, as well as actuators such as steam regulating valves and feed pumps 20. The monitoring sensors 503 monitor parameters such as pressure, temperature, and liquid level inside the reaction tank in real time and transmit them to the PLC. Adaptive control and fuzzy control technologies are introduced into the PLC's control algorithm. Adaptive control automatically adjusts control parameters based on real-time monitoring data inside the reaction tank, enabling the system to better adapt to changes in the composition and treatment conditions of the liquid hazardous waste. Fuzzy control handles factors that are difficult to quantify precisely, such as the rate of liquid level change and the amplitude of temperature fluctuations, allowing for more flexible control of the steam regulating valve and feed pump 20, improving control accuracy and stability.

[0045] Example 2:

[0046] A multi-effect evaporation and crystallization device for liquid hazardous waste, such as Figure 1As shown, the device includes: a feed buffer tank 10, a feed pump 20, a delivery pipe 30, an automated control system 40, and an evaporation reaction tank 50. This utility model is a device for precisely and intelligently performing multi-effect evaporation of liquid hazardous waste based on relevant parameters within the evaporation reaction tank. The feed buffer tank 10 is connected to the evaporation reaction tank 50 via the feed pump 20, and the feed pump 20 is connected to both the feed buffer tank 10 and the evaporation reaction tank 50 via the delivery pipe 30. A stirrer 103 is installed inside the feed buffer tank 10.

[0047] Preferably, the feed buffer tank 10 and the evaporation reaction tank 50 are both cylindrical tanks. Specifically, the feed buffer tank 10 and the evaporation reaction tank 50 are made of corrosion-resistant stainless steel.

[0048] Preferably, a frame-type stirring mechanism 504 and an anchor-type stirring mechanism 505 are respectively provided on the upper and lower sides of the interior of the evaporation reaction tank 50. A metal wire mesh corrugated packing layer 506 is provided on the top of the interior of the evaporation reaction tank 50, and several baffles 507 are provided at the bottom of the metal wire mesh corrugated packing layer 506. A monitoring sensor 503 is provided inside the tank wall of the evaporation reaction tank 50, and a heat insulation layer 509 is provided on the outer wall of the tank. Specifically, the feed buffer tank 10 is used to temporarily store the pre-treated and impurity-removed liquid hazardous waste. The internal variable speed stirrer 103 prevents the material from settling and stratifying, ensuring that the material composition entering the subsequent process is uniform and stable, laying a good foundation for the subsequent processing stages. At the same time, the material is transported to the metering water tank by high-level gravity flow to realize the automatic transfer of the material.

[0049] Specifically, the evaporation reactor 50, as the core processing equipment, achieves low-temperature evaporation and drying of liquid hazardous waste under vacuum negative pressure and steam jacket heating conditions, reducing secondary pollution. The frame-type stirring mechanism 504, the anchor-type stirring mechanism 505, and the corrugated metal mesh packing layer 506 inside the evaporation reactor 50 work synergistically. The frame-type stirring mechanism 504 and the anchor-type stirring mechanism 505 ensure uniform mixing and heating of the materials, facilitating evaporation and slag discharge; the corrugated metal mesh packing layer 506 increases the evaporation contact area, collectively improving evaporation efficiency and reducing energy consumption. The processed solid slag is automatically discharged, and the evaporation condensate is collected and treated at a wastewater treatment plant.

[0050] Specifically, the automated control system 40 is based on a PLC, and adaptive control and fuzzy control technologies can be introduced into the PLC's control algorithm. The automated control system 40 monitors key parameters such as pressure, temperature, and liquid level inside the reaction tank in real time through various monitoring sensors. Adaptive control automatically adjusts control parameters based on the real-time monitoring data inside the reaction tank, enabling the system to better adapt to changes in the composition and treatment conditions of the liquid hazardous waste. Existing fuzzy control technology can be used to handle factors that are difficult to quantify precisely, such as controlling the steam regulating valve and feed pump more flexibly based on fuzzy information such as the rate of liquid level change and the amplitude of temperature fluctuations, thereby improving the accuracy and stability of control. The adaptive control and fuzzy control technologies mentioned are existing technologies and will not be described in detail here.

[0051] The conveying pipe 30 serves as a bridge connecting the feed buffer tank 10 and the evaporation reactor 50, acting as a channel for transporting liquid hazardous waste from the feed buffer tank 10 to the evaporation reactor 50. One end of the conveying pipe 30 extends into the outlet of the feed buffer tank, and the other end connects to the inlet of the evaporation reactor 50. Correspondingly, matching flanges are installed at the outlet of the feed buffer tank 10 and the inlet 50 of the evaporation reactor, with a rubber sealing gasket installed in between, and connected using quick-release bolts. This structure facilitates quick disassembly and installation during equipment maintenance or repair, improving work efficiency while ensuring the sealing of the connection to prevent leakage of liquid hazardous waste.

[0052] In operation, the pre-treated and impurity-removed liquid hazardous waste is first added to the feed buffer tank 10. The agitator 103 is then turned on, and the material is mixed evenly at different speeds to prevent sedimentation and stratification. Next, the material is conveyed to the evaporation reactor 50 through the conveying pipe 30, where steam is introduced for heating. Under a vacuum pressure of -90Kpa to -80Kpa and a steam temperature of 105-120℃, the temperature inside the tank is maintained at 45-65℃ for low-temperature evaporation. The frame-type agitator 504 and the anchor-type agitator 505 continuously stir the material. The anchor-type agitator 505 pushes the solid slag towards the discharge port, while the frame-type agitator 504 ensures uniform mixing and heating. As evaporation continues, the moisture in the liquid hazardous waste gradually evaporates, and the remaining solid slag moves towards the discharge port under the push of the anchor-type agitator 505 at the bottom of the tank. When the solid slag accumulates to a certain extent, it is automatically pushed out by the elastic scraper 5052 of the anchor-type agitator 505 inside the tank, completing the automatic slag discharge. The steam generated by evaporation rises and cools to form condensate, which is collected and transported to a wastewater treatment plant for further treatment. The automated control system can monitor key parameters such as pressure, temperature, and liquid level within the reaction tank in real time using sensors 503 and thermometers 502. Based on preset programs and algorithms, it automatically controls actuators such as steam regulating valves and feed pumps to achieve precise regulation of steam flow rate and feed speed. The automated control system 40 is existing technology and not an improvement of this invention; therefore, it will not be described in detail.

[0053] Preferably, the workflow of this utility model is as follows:

[0054] 1) Temporary storage of liquid hazardous waste: The feed buffer tank 10 is sealed to store liquid hazardous waste. An internal variable speed agitator 103 prevents material sedimentation and stratification, ensuring that the material composition entering subsequent processes is uniform and stable, laying a good foundation for subsequent treatment stages. At the same time, the material is transported to the metering tank by gravity flow, realizing automatic material transfer.

[0055] 2) Liquid Hazardous Waste Transportation: The feed buffer tank 10 is connected to the evaporation reactor 50 via a conveying pipe 30. A magnetic level gauge 301 on the conveying pipe 30 monitors the liquid level in real time. Liquid hazardous waste enters the evaporation reactor 50 from the outlet of the feed buffer tank 10 via the conveying pipe 30 and through the inlet of the evaporation reactor 50. Matching flanges are installed at the outlet 104 of the feed buffer tank 10 and the inlet 101 of the evaporation reactor 50, with a rubber sealing gasket installed in between, and connected by quick-release bolts. This structure facilitates quick disassembly and installation during equipment maintenance or repair, improving work efficiency, while ensuring the sealing of the connection to prevent leakage of liquid hazardous waste.

[0056] 3) Multi-effect evaporation of liquid hazardous waste: Liquid hazardous waste enters through the inlet of evaporation reactor 50. The reactor is maintained at a vacuum pressure of -90 kPa to -80 kPa, heated by a steam jacket with the jacket working pressure controlled below 0.1 MPa and the heating steam temperature at 105-120°C. Under the action of jacket heating, the liquid hazardous waste in the reactor begins to evaporate. Due to the vacuum pressure inside the reactor, its evaporation temperature is maintained in a low-temperature range of 45-65°C. During this process, the stirring device inside the reactor starts working, with the frame-type stirring mechanism 504 in the middle continuously stirring, ensuring uniform heating of the liquid hazardous waste and accelerating the evaporation rate. Simultaneously, the structured packing material filling the upper part of the reactor greatly increases the contact area between the waste liquid and the steam, enhancing the evaporation process and improving evaporation efficiency. A baffle plate 507, made of stainless steel and wavy in shape, is added below the corrugated metal mesh packing layer 506. The height and spacing of its crests and troughs are optimized according to the size of the reaction tank and the evaporation characteristics of the waste liquid, allowing the steam to change direction multiple times during its ascent, increasing the contact time and opportunities with the waste liquid, and enhancing the heat and mass transfer process. As evaporation continues, the moisture in the liquid hazardous waste is gradually evaporated, and the remaining solid slag is moved towards the discharge port 510 by the anchor-type stirring mechanism 505 at the bottom of the tank. When the solid slag accumulates to a certain extent, it is automatically pushed out by the stirring scraper inside the tank, completing the automatic slag discharge. The steam generated by evaporation rises, cools, and forms condensate. This condensate is collected and transported to a wastewater treatment plant for advanced treatment. The treated condensate can be reused, achieving the goal of water resource recycling. After completing one treatment and slag discharge cycle, the above reaction process is repeated to achieve continuous batch treatment of liquid hazardous waste.

[0057] 4) Intelligent Control: Based on a PLC, adaptive control and fuzzy control technologies are incorporated into the PLC's control algorithm. Various monitoring sensors 503 monitor key parameters within the reaction tank in real time, such as pressure, temperature, and liquid level. Adaptive control automatically adjusts control parameters based on real-time monitoring data, enabling the system to better adapt to changes in the composition and treatment conditions of the liquid hazardous waste. Fuzzy control addresses factors that are difficult to quantify precisely, such as the rate of liquid level change and the amplitude of temperature fluctuations, allowing for more flexible control of the steam regulating valve and feed pump 20, improving control accuracy and stability.

[0058] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A multi-effect evaporation and crystallization device for liquid hazardous waste, characterized in that, The system includes a feed buffer tank (10) and several evaporation reaction tanks (50). The outlet (104) of the feed buffer tank (10) is connected to the inlet (501) of several evaporation reaction tanks (50) via a feed pump (20). The feed buffer tank (10) is equipped with a feed stirring mechanism and is used to homogenize and store the liquid to be processed. The top of the evaporation reaction tank (50) is equipped with a metal wire mesh corrugated packing layer (506), and the bottom of the evaporation reaction tank (50) is equipped with a discharge port (510). The upper and lower sides of the evaporation reaction tank (50) are respectively equipped with a frame stirring mechanism (504) and an anchor stirring mechanism (505). The outer side of the frame stirring mechanism (504) is equipped with a guide tube (5041), and the bottom of the metal wire mesh corrugated packing layer (506) above the guide tube (5041) is equipped with several baffles (507).

2. The multi-effect evaporation and crystallization device for liquid hazardous waste according to claim 1, characterized in that, The anchor stirring mechanism (505) includes an anchor stirring motor (5053) and an anchor stirring blade (5051). The anchor stirring motor (5053) is installed at the bottom of the evaporation reaction tank (50), and the driving end of the evaporation reaction tank (50) extends into the evaporation reaction tank (50) and is connected to the anchor stirring blade (5051). An elastic scraper (5052) that is in close contact with the evaporation reaction tank (50) is provided on the outer side of the anchor stirring blade (5051) along the length direction.

3. The multi-effect evaporation and crystallization device for liquid hazardous waste according to claim 1, characterized in that, The frame-type stirring mechanism (504) includes a frame-type stirring motor (5044), a stirring shaft (5043), and a frame-type stirring blade (5042). The frame-type stirring motor (5044) is installed on the top of the evaporation reaction tank (50), and the driving end of the evaporation reaction tank (50) extends into the evaporation reaction tank (50) and is connected to the frame-type stirring blade (5042) through the stirring shaft (5043); a guide tube (5041) is provided on the outside of the frame-type stirring blade (5042).

4. A multi-effect evaporation and crystallization device for liquid hazardous waste according to any one of claims 1-3, characterized in that, The feed pump (20) is connected to the feed buffer tank (10) and the evaporation reaction tank (50) through the delivery pipe (30), and a static mixer (302) is installed inside the delivery pipe (30) near the evaporation reaction tank (50), and a magnetic float level gauge (301) is installed on the delivery pipe (30) near the feed pump (20).

5. The multi-effect evaporation and crystallization device for liquid hazardous waste according to claim 1, characterized in that, The top two sides of the feed buffer tank (10) are respectively provided with a feed inlet (101) and a discharge outlet (104); the feed stirring mechanism includes a feed stirring motor (102) and a stirrer (103). The feed stirring motor (102) is installed in the middle of the top of the feed buffer tank (10). The drive end of the feed stirring motor (102) extends into the feed buffer tank (10) and is connected to the stirrer (103).

6. The multi-effect evaporation and crystallization device for liquid hazardous waste according to claim 1, characterized in that, The evaporation reactor (50) is provided with an insulation layer (509) on the outside, and a steam inlet (508) is provided on the side wall of the evaporation reactor (50). A drain outlet (511) is also provided at the bottom of the evaporation reactor (50).

7. A multi-effect evaporation and crystallization device for liquid hazardous waste according to claim 1 or 6, characterized in that, A thermometer (502) is installed on the top of the evaporation reactor (50), and several monitoring sensors (503) are installed on the inner sidewall of the evaporation reactor (50).

8. A multi-effect evaporation and crystallization device for liquid hazardous waste according to claim 7, characterized in that, It also includes a PLC, which is connected to the feed pump (20), the feed stirring mechanism, the frame stirring mechanism (504), the anchor stirring mechanism (505), the thermometer (502), and the monitoring sensor (503).

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