Dissolved liquid concentration evaporation reactor based on energy-saving heat exchange device and control method

Abstract

The present application relates to the technical field of chemical concentration evaporation equipment, in particular to a kind of dissolving liquid concentration evaporation reaction kettle based on energy-saving heat exchange device and control method, including the preheating of the to-be-concentrated dissolving liquid after waste heat preheating coil is sent into kettle body;After feeding is completed, close feed valve and kettle body and pipeline valve establish sealed environment;Start jacket and built-in coil double-layer heating module, synchronously heat dissolving liquid in kettle;PLC control system real-time acquisition temperature, liquid level, vacuum degree signal, and closed-loop automatic regulation heating power, stirring speed and vacuum pump load.The present application is by PLC control system temperature, liquid level, vacuum degree is included in the same closed-loop control logic;When liquid level drops, system automatically corrects heating power and vacuum degree set value, so that evaporation rate and concentration process always keep matching, avoid because evaporate too fast and lead to local concentration too high, or evaporate too slow and lead to concentration period too long.

Description

Technical Field

[0001] This invention relates to the field of chemical concentration and evaporation equipment technology, specifically to a solution concentration and evaporation reactor and control method based on an energy-saving heat exchange device. Background Technology

[0002] Solution concentration and evaporation reactors are core equipment in hydrometallurgy, fine chemicals, and pharmaceutical chemicals. Through heating and reduced / normal pressure evaporation processes, they achieve the vaporization and separation of solvents in the solution, thus concentrating and enriching the solute. Currently, the industry mainly uses three types of equipment: traditional enamel-lined reactors, ordinary stainless steel jacketed evaporators, and single-effect normal pressure evaporators.

[0003] In the prior art, patent application CN204522318U discloses a vacuum depressurization concentration tank for artemisinin extract. This patented technology can improve concentration efficiency, but it uses a jacketed structure for heating, which can only heat a local area and is prone to local scorching. Patent application CN211302108U discloses a high-efficiency depressurization concentration and collection device, which uses a heating jacket on the outer wall of the concentrator tank for heating and can adjust the speed of the scraper. However, this device relies on heating only on one side of the jacket, and the heating uniformity is still insufficient, and there is no temperature-liquid level-vacuum degree linkage control system. Patent application CN206304611U discloses a dispersion vessel, which uses an anchor-type stirring paddle combined with a wall scraping device to solve the problem of high-viscosity materials sticking to the wall. However, this patent does not involve the coordinated operation of the heating module and the stirring module, nor does it involve three-parameter linkage control.

[0004] The aforementioned existing technologies have not solved the following core technical problems: First, they suffer from low heat exchange efficiency, high heat conduction loss, low concentration efficiency, and high energy consumption; second, they lack a precise temperature control and liquid level linkage system, making it difficult to accurately control the concentration. Therefore, there is an urgent need for a solution concentration and evaporation reactor and control method that can achieve uniform heating throughout the entire process, precise temperature control, high solvent recovery rate, anti-coking, and energy saving. Summary of the Invention

[0005] In order to overcome the defects in the prior art, the purpose of this invention is to provide a solution concentration and evaporation reactor and control method based on an energy-saving heat exchange device, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, on the one hand, the present invention provides a control method for the concentration and evaporation reaction of a solution based on an energy-saving heat exchange device, comprising using a vertical integrated concentration and evaporation reactor to concentrate and evaporate the solution. The reactor includes a reactor body, a double-layer heating module consisting of a jacket and built-in coils, a variable frequency anchor-type wall-scraping stirring module, a vacuum evaporation module, a condensation recovery module, and a PLC intelligent control module; the method includes the following steps: S1. Feed preheating: The solution to be concentrated and dissolved is preheated by the waste heat preheating coil and then fed into the reactor. Feeding is stopped after the set liquid level is reached. S2. Sealing and Vacuum Establishment: Start the anchor scraper agitator. After feeding is completed, close the feed valve and valves of the vessel body and pipeline to establish a sealed environment. Start the vacuum pump to make the vessel reach the set vacuum level and keep it constant. S3, Dual-layer synchronous heating: The jacket and built-in coil dual-layer heating module are activated to simultaneously heat the solution in the kettle, while the anchor-type scraper agitator continuously refreshes the heating surface of the liquid. S4. Three-parameter linkage control: The PLC control system collects temperature, liquid level, and vacuum signals in real time, and automatically adjusts the heating power, stirring speed, and vacuum pump load in a closed loop. The PLC control system integrates a temperature sensor, a liquid level sensor, a vacuum sensor, and an online concentration detection unit, and executes the following linkage logic: automatically increasing heating power and vacuum when the liquid level decreases; automatically adjusting heating power and stirring speed when the temperature exceeds the set range; automatically adjusting vacuum pump load when the vacuum fluctuates; and automatically stopping heating, breaking the vacuum, and discharging material when the concentration reaches the set value. S5. Concentration Evaporation and Solvent Recovery: While S3 and S4 are being carried out, the solution is heated and vaporized. The solvent vapor enters the condensation and recovery module, is condensed into liquid and recovered. The residual heat from condensation is used to preheat the feed solution. S6. Concentration endpoint control: When the online concentration detection or liquid level signal reaches the set concentration endpoint, heating is stopped, stirring and condensation are maintained, and then the vacuum is broken to restore normal pressure; S7. Discharge and cleaning: Open the discharge valve to discharge the concentrate.

[0007] As a further improvement to this technical solution, in step S1, the waste heat preheating coil is connected in series with the feed pipeline, and the waste heat from the condensation recovery module is used as a heat source to preheat the solution; when the liquid level in the reactor reaches the set range, the feeding is stopped.

[0008] As a further improvement to this technical solution, in step S2, the vessel body is sealed with a combination of a quick-connect flange and a double-layer sealing gasket; the vacuum degree is adjusted to -0.07 to -0.1 MPa and kept constant, and the vacuum degree sensor provides real-time feedback to the PLC to adjust the vacuum pump load.

[0009] As a further improvement to this technical solution, in step S3, the jacket covers the outer wall of the vessel, the built-in coil extends into the liquid inside the vessel, the jacket and the built-in coil are connected in parallel to the same heat source and heat up and stop at the same time; the outer edge of the blade of the anchor-type scraper is provided with a polytetrafluoroethylene scraper strip, the gap between the scraper strip and the inner wall of the vessel is ≤5mm, and the scraper strip continuously scrapes off the material adhering to the inner wall and the surface of the coil.

[0010] As a further improvement to this technical solution, in step S4, when the temperature exceeds the set range, the PLC prioritizes adjusting the heating power; when the heating power is adjusted to the limit and still exceeds the set range, the stirring speed is then adjusted; in step S6, after reaching the concentration endpoint, stirring and condensation are maintained for 3 to 5 minutes, and then the vacuum is broken to restore normal pressure.

[0011] On the other hand, the present invention provides a solution concentration and evaporation reactor based on an energy-saving heat exchange device, and employs a control method for the solution concentration and evaporation reaction based on an energy-saving heat exchange device, including: The vessel body has a steam port at the top, a vacuum port on the side, and a discharge valve at the bottom; The double-layer heating module includes a jacket covering the outer wall of the vessel and an internal coil spirally arranged on the outer wall of the vessel. The jacket and the internal coil are connected in parallel to the same heat source. The stirring module includes a frequency-controlled anchor-type wall-scraping stirring device vertically installed at the center of the vessel body. The outer edge of the stirring paddle is provided with a polytetrafluoroethylene wall-scraping strip, and the gap between the wall-scraping strip and the inner wall of the vessel body is ≤5mm. The vacuum evaporation module includes a vacuum pump and a vacuum sensor, and is connected to the vacuum port of the vessel. The condensation recovery module includes a condenser and a solvent storage tank connected to the steam port of the reactor body, and is equipped with a waste heat preheating coil connected in series with the feed pipeline. The PLC intelligent control module integrates temperature sensors, liquid level sensors, and vacuum sensors, and is connected to the double-layer heating module, stirring module, and vacuum evaporation module respectively to achieve linkage control of three parameters: temperature, liquid level, and vacuum.

[0012] As a further improvement to this technical solution, the vessel body seal adopts a double-layer sealing structure consisting of a quick-install flange and a fluororubber gasket or a PTFE-coated fluororubber gasket; the inner wall of the vessel body is provided with a polytetrafluoroethylene anti-stick coating, and the vessel body adopts a detachable or quick-release structure.

[0013] As a further improvement to this technical solution, the condenser of the condensation recovery module is a shell-and-tube condenser or a plate heat exchanger, and the condenser is connected to the solvent storage tank; the waste heat preheating coil is wound or connected in series with the feed pipeline to preheat the feed solution using the waste heat from condensation.

[0014] As a further improvement to this technical solution, the PLC intelligent control module also includes an online concentration detection unit, configured to perform the following linkage control: increase heating power and vacuum degree when the liquid level drops; adjust heating power and stirring speed when the temperature exceeds the tolerance; adjust vacuum pump load when the vacuum fluctuates; stop heating, break vacuum and discharge material when the concentration reaches the standard.

[0015] As a further improvement to this technical solution, one or more of the following are also included: An inert gas protection module is used to fill the vessel with nitrogen or argon gas; The CIP cleaning module integrates a high-pressure cleaning nozzle and a cleaning fluid circulation system. The remote monitoring and fault alarm module is used to remotely view operating parameters and realize remote start / stop and fault alarm. The solvent distillation module, connected in series with the condensation recovery module, is used to purify the recovered solvent by distillation. The vacuum pump of the vacuum evaporation module is a Roots water ring vacuum unit.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The solution concentration and evaporation reactor and control method based on the energy-saving heat exchange device, through the coordinated cooperation of the jacket and built-in coil double-layer heating and the anchor scraping and stirring, the jacket and coil are connected in parallel to the same heat source, and the heating is introduced and stopped synchronously, so as to achieve uniform heating of the solution throughout the whole area, and structurally prevent solute coking and decomposition caused by local overheating.

[0017] 2. The solution concentration and evaporation reactor and control method based on the energy-saving heat exchange device incorporate temperature, liquid level and vacuum degree into the same closed-loop control logic through the PLC control system, rather than adjusting them independently. The liquid level change directly reflects the amount of remaining liquid in the reactor and the concentration process. When the liquid level drops, the system automatically corrects the heating power and vacuum degree set value to keep the evaporation rate and concentration process matched at all times, avoiding excessively high local concentration due to excessively fast evaporation or excessively long concentration cycle due to excessively slow evaporation. Attached Figure Description

[0018] The accompanying drawings described herein are for illustrative purposes only.

[0019] Figure 1 This is a schematic diagram of the overall layout structure of the present invention; Figure 2 This is a control principle diagram of the present invention; Figure 3 This is the overall control flowchart of the present invention; Figure 4 This is a flowchart of the three-parameter linkage control of the present invention; 100. Kettle body; 110. Jacket; 120. Built-in coil; 130. Discharge valve; 200. Anchor-type scraper agitator; 210. Scraper bar; 220. Motor; 300. Vacuum pump; 400. Condenser; 500. Storage tank; 600. Feed pipe; 700. Preheating coil. Detailed Implementation

[0020] Under the guidance of this invention, any possible variations of this invention should be considered within the scope of this invention.

[0021] Please see Figures 1-4 As shown, the present invention provides a solution concentration and evaporation reactor based on an energy-saving heat exchange device. The reactor is a vertical integrated concentration and evaporation reactor, including a reactor body 100, a double-layer heating module, a stirring module, a vacuum evaporation module, a condensation recovery module, and a PLC intelligent control module.

[0022] Specifically, the vessel body 100 is made of vertical 316L stainless steel with a volume of 50-5000L. The inner wall of the vessel body 100 is coated with a polytetrafluoroethylene (PTFE) anti-stick coating with a thickness of 0.3-0.5mm. The vessel body 100 is sealed with a double-layer sealing structure consisting of a quick-connect flange and a high-temperature resistant fluororubber gasket or a PTFE-coated fluororubber gasket. The vacuum pressure range is -0.1~0.2MPa, and the operating temperature is room temperature to 200℃. The vessel body 100 has a steam port and a feed port at the top, a vacuum port on the side, and a discharge valve 130 at the bottom. The vessel body 100 adopts a detachable or quick-release structure for easy cleaning and material replacement.

[0023] The double-layer heating module includes a jacket 110 covering the outer wall of the vessel body 100 and an internal coil 120 spirally arranged on the outer wall of the vessel body 100. The jacket 110 is welded and sealed to the outer wall of the vessel body 100, forming an outer heat exchange chamber; the internal coil 120 can also extend into the inner wall of the vessel body 100. The jacket 110 and the internal coil 120 are connected in parallel to the same heat source, allowing for simultaneous heating and heating shutdown. The heat exchange medium is heat transfer oil or steam, the heating power is 10-150kW, and the temperature control accuracy is ±0.5℃. The jacket 110 is responsible for heating the outer liquid, while the internal coil 120 is responsible for heating the central liquid. Simultaneous heating from both inside and outside achieves uniform heating throughout the entire area, eliminating hot and cold zones and localized overheating. The heating method of jacket 110 is as follows: heat transfer oil or steam is introduced from the heat source through oil / steam inlet pipes into the heat exchange medium inlet of jacket 110 and the heat exchange medium inlet of built-in coil 120, respectively. It flows synchronously within the heat exchange chamber of jacket 110 and the coil, exchanging heat with the outer wall of vessel 100 and the liquid inside the vessel. Afterward, it flows back to the heat source from the heat exchange medium outlets of jacket 110 and built-in coil 120, forming a closed-loop circulation circuit. Where the heat exchange medium inlet and outlet pass through the vessel wall or lid, they are sealed using a combination of quick-install flanges and high-temperature resistant fluororubber gaskets or PTFE-coated fluororubber gaskets, matching the vacuum pressure range of vessel 100.

[0024] The stirring module employs a variable frequency speed-regulating anchor-type wall-scraping stirring device 200, vertically installed on the central shaft of the vessel body 100, extending through the vessel lid and into the vessel bottom. A polytetrafluoroethylene (PTFE) wall-scraping strip 210 is installed on the outer edge of the stirring paddle, with a gap of ≤5mm between the wall-scraping strip 210 and the inner wall of the vessel body 100. The wall-scraping strip 210 continuously scrapes away material adhering to the inner wall. The stirring speed is 5-60 r / min, and the motor 220 has a power of 2.2-37 kW. Based on the above structure of the stirring module extending through the vessel lid and into the vessel bottom, a mechanical seal or magnetic coupling seal is installed at the point where the stirring shaft penetrates the vessel lid. When a mechanical seal is used, the sealing surface material is silicon carbide or tungsten carbide, supplemented with a fluororubber O-ring. This dynamic seal, together with the quick-install flange and double-layer sealing gasket, meets the vacuum / pressure sealing requirements of -0.1~0.2 MPa and room temperature~200℃.

[0025] The vacuum evaporation module includes a rotary vane vacuum pump 300 or a Roots water ring vacuum unit and a vacuum sensor, connected to the vacuum port of vessel 100. The vacuum adjustment range is 0.01~0.1MPa (gauge pressure), supporting automatic vacuum constant setting. The vacuum sensor is installed on the vacuum port pipeline of vessel 100, with a measurement range of -0.1~0MPa (gauge pressure) and an accuracy of ±0.5%FS. Unless otherwise specified, vacuum levels are expressed in gauge pressure; negative values ​​indicate pressure below atmospheric pressure, and the larger the absolute value of the negative value, the higher the vacuum level. The vacuum pressure range, vacuum adjustment range, and vacuum sensor measurement range are all uniformly described according to this gauge pressure definition.

[0026] The condensation recovery module includes a shell-and-tube condenser 400 or a plate heat exchanger connected to the steam port of the vessel body 100, and a solvent storage tank 500. The condensation area is 5-50 m², and the condensation temperature is 5-25℃. A preheating coil 700 is provided, with a heat exchange area of ​​3-30 m². The preheating coil 700 is connected in series with the feed pipe 600 to preheat the feed solution using waste heat from condensation. The preheating coil 700 is located in the cooling water return line of the condenser 400 or at the shell-side outlet of the condenser 400, and is connected in series with the feed pipe 600. The cooling water return line or waste heat from condensation of the condenser 400 first exchanges heat with the preheating coil 700, and then flows back to the cooling system. The feed solution is preheated to 30-40℃ by the preheating coil 700 before entering the vessel body 100. The steam port at the top of the vessel body 100 is connected in sequence to the condenser 400 and the solvent storage tank 500. The gas outlet of the condenser 400 is connected to the vacuum evaporation module, so that the uncondensed gas is discharged through the vacuum pump 300 and the condensate flows into the solvent storage tank 500 for recovery.

[0027] The PLC intelligent control module integrates a temperature sensor, a liquid level sensor, a vacuum sensor, and an online concentration detection unit, which are respectively connected to the double-layer heating module, the stirring module, and the vacuum evaporation module to achieve linkage control of three parameters: temperature, liquid level, and vacuum.

[0028] It is worth noting that the PLC intelligent control module adopts an industrial-grade programmable logic controller, equipped with analog input modules, analog output modules, and digital input / output modules. Signal acquisition includes: a temperature sensor; installed in the liquid at the bottom of the vessel 100, with a measurement range of 0~250℃ and an accuracy of ±0.1℃; The liquid level sensor is a submersible pressure level transmitter; it is installed at the bottom of the vessel body 100, with a measurement range of 0~100% and an accuracy of ±0.5%FS; Vacuum sensor; installed on the 100mm vacuum port pipeline of the vessel, measuring range -0.1~0MPa (gauge pressure), accuracy ±0.5%FS; An online concentration detection unit is installed on the side circulation pipeline of the vessel body 100. Based on the principle of refractive index or density, the measurement range is 0~100%, with an accuracy of ±0.5%. Due to the installation location of the online concentration detection unit, the side circulation pipeline of the vessel body 100 extends from the lower part of the vessel body 100, passes through the circulation pump and the online concentration detection unit, and returns to the upper part of the vessel body 100. An isolation valve is installed on the pipeline. The online concentration detection unit is connected to the PLC intelligent control module and transmits the real-time concentration signal to the PLC analog input module.

[0029] All sensor signals are transmitted to the PLC analog input module via shielded cables, with a sampling period of 100ms.

[0030] Specifically, the PLC intelligent control module controls the following actuators through the analog output module: heating power regulator; adjusts the heating power of jacket 110 and coil, with an adjustment range of 0~100%; stirring frequency converter; controls the speed of stirring motor 220, with an adjustment range of 5~60 r / min; vacuum pump 300 frequency converter; controls the speed of vacuum pump 300 motor 220 and adjusts the load of vacuum pump 300. The PLC controls the opening and closing of the feed valve, discharge valve 130, vacuum breaking valve, and CIP cleaning valve through the digital output module. The CIP cleaning module includes a cleaning fluid storage tank, a circulation pump, a high-pressure spray ball, and a valve group; the high-pressure spray ball is set at the top of the vessel body 100 or inside the vessel cover, the inlet of the circulation pump is connected to the bottom of the vessel body 100 through the discharge valve 130, and the outlet of the circulation pump is connected to the high-pressure spray ball through the CIP cleaning valve. The cleaning fluid is discharged after high-pressure spraying and bottom circulation cleaning for 15~30 minutes.

[0031] Specifically, the three-parameter linkage control adopts a hierarchical control strategy of primary control parameter + secondary control parameter, with temperature as the controlled primary parameter and liquid level and vacuum degree as controlled secondary parameters. The control logic is as follows: (1) Temperature-heating power closed-loop control: The PLC will control the actual temperature T collected by the temperature sensor. 实际 With the set temperature T 设定 Compare and calculate the deviation e T equal to T 设定With T 实际 difference.

[0032] when|e T When |≤0.5℃, maintain the current heating power unchanged; when e T When the temperature is above 0.5℃, the heating power is increased according to the PID algorithm; the PID parameters are: proportional coefficient Kp = 2.0, integral time Ti = 120s, derivative time Td = 30s; when e T When the temperature is below -0.5℃, the heating power is reduced according to the PID algorithm. The heating power output range is 0~100%, corresponding to a heating power of 10~150kW.

[0033] (2) Liquid level-heating power / vacuum linkage control: When the liquid level sensor detects the liquid level L in the vessel... 实际 When the liquid level falls below the set lower limit Lmin (e.g., 30%), the PLC automatically increases the heating power to 110%~130% of the current set value, and simultaneously adjusts the vacuum setting value to a more negative direction by 0.005~0.01MPa, i.e., increases the absolute value of the vacuum, accelerating the solvent evaporation and concentration process; when the liquid level Lmin... 实际 When the liquid level exceeds the upper limit of the set liquid level Lmax (e.g., 70%), the PLC automatically reduces the heating power to 70%~90% of the current set value, and at the same time adjusts the vacuum setting value towards atmospheric pressure by 0.005~0.01MPa, that is, reduces the absolute value of the vacuum degree to prevent the liquid from overflowing and excessive evaporation.

[0034] (3) Vacuum degree - Vacuum pump 300 load closed-loop control: The vacuum degree sensor outputs gauge pressure P, ranging from -0.1 to 0 MPa. The PLC converts the actual vacuum degree P collected by the vacuum degree sensor into P. 实际 With the set vacuum degree P 设定 Compare and calculate the deviation e P equals P 设定 With P 实际 difference.

[0035] when|e P When |≤0.002MPa, maintain the current vacuum pump load of 300; when e P When it is less than -0.002 MPa, it means P 实际 Higher than P 设定 The actual vacuum level is insufficient. Increase the output frequency of the 300V inverter for the vacuum pump to increase its speed. P When it is greater than 0.002 MPa, it indicates that P 实际 Below P 设定 If the actual vacuum level is too high, reduce the output frequency of the vacuum pump 300 inverter. The load adjustment range of the vacuum pump 300 is 30%~100%.

[0036] (4) Temperature deviation classification adjustment logic: When the temperature deviation |e T When the temperature is above 2℃, the PLC prioritizes adjusting the heating power. If the heating power has already been adjusted to its limit (0% or 100%), |e T If the temperature remains above 2℃, the PLC will activate a graded adjustment strategy: when the temperature is too high (e T When the temperature is below -2℃, while reducing the heating power to 0%, increase the stirring speed to 120%~150% of the current setting to enhance the convective heat dissipation of the liquid; when the temperature is low (e T When the temperature is above 2°C, while increasing the heating power to 100%, reduce the stirring speed to 50%~70% of the current setting value to reduce heat loss.

[0037] Furthermore, the online concentration detection unit monitors the concentration C of the concentrated solution in the reactor in real time. 实际 and compared it with the set concentration endpoint C. 设定 Compare them.

[0038] When C 实际 ≥C 设定 When the PLC automatically executes the following shutdown sequence: First, stop the heating module, keep the stirring and condensation recovery modules running for 3-5 minutes to allow residual solvent vapors to be fully condensed and recovered; then, turn off the vacuum pump 300, open the vacuum breaking valve to restore the pressure inside the vessel to atmospheric pressure, and finally open the discharge valve 130 to discharge the concentrate. If the online concentration detection unit malfunctions, the liquid level signal is used as the backup endpoint judgment basis. When the liquid level drops to the set lower limit Lfinal (e.g., 10%~15%), the shutdown sequence is triggered.

[0039] In addition, the PLC has built-in safety interlock protection logic: ① Temperature over-limit protection: When the temperature inside the vessel exceeds the set upper temperature limit +5℃, the power supply to the heating module is automatically cut off, and the cooling water valve is opened at the same time; ② Vacuum abnormality protection: When the vacuum degree reaches the gauge pressure limit of -0.1MPa or the absolute pressure is close to 0, the vacuum pump 300 is automatically shut off and the vacuum breaking valve is opened; ③ Liquid level too low protection: When the liquid level is below 5%, the stirring motor 220 is automatically stopped to prevent the stirring paddle from running dry and damaging the equipment; ④ Stirring overload protection: When the current of the stirring motor 220 exceeds 120% of the rated current, the stirring speed is automatically reduced and an alarm signal is issued.

[0040] The present invention provides a method for controlling the concentration and evaporation reaction of a solution based on an energy-saving heat exchange device, comprising the following steps: S1. Feed preheating: The solution to be concentrated and dissolved is preheated to 30~40℃ through the preheating coil 700 and then fed into the reactor body 100. When the liquid level in the reactor reaches 30%~70%, the feeding is stopped.

[0041] S2. Sealing and Vacuum Establishment: Start the anchor-type scraper agitator and adjust the speed to 10~60r / min; after feeding is completed, close the feed valve and the valves of the vessel body 100 and pipeline to establish a sealed environment; start the vacuum pump 300 and adjust the vacuum degree inside the vessel to -0.07~-0.1MPa (gauge pressure) and keep it constant.

[0042] S3. Dual-layer synchronous heating: Start the dual-layer heating module of jacket 110 and built-in coil 120, using heat transfer oil or steam as the heat exchange medium, and control the temperature inside the vessel at room temperature to 200℃ according to the characteristics of the solution, with a temperature control accuracy of ±0.5℃; at the same time, the heating surface of the liquid is continuously renewed by anchor scraping and stirring.

[0043] S4. Three-parameter linkage control: The PLC control system collects temperature, liquid level and vacuum signals in real time, and automatically adjusts the heating power, stirring speed and vacuum pump load in a closed loop.

[0044] S5. Concentration, Evaporation and Solvent Recovery: While S3 and S4 are in progress, the solution is heated and vaporized. The solvent vapor enters the condensation and recovery module, where it is condensed into a liquid and recovered. The residual heat from the condensation is used to preheat the feed solution.

[0045] S6. Concentration endpoint control: When the online concentration detection or liquid level signal reaches the set concentration endpoint, stop heating, maintain stirring and condensation for 3-5 minutes, and then break the vacuum to restore normal pressure.

[0046] S7. Discharge and cleaning: Open discharge valve 130 to discharge the concentrate; when switching materials, start the CIP cleaning module for high-pressure spraying and circulating cleaning for 15~30 minutes.

[0047] To further demonstrate the feasibility of the present invention, the following specific embodiments are provided. The parameters in the following embodiments are fixed values, used to support the above parameter range and technical effects.

[0048] Example 1: Small-scale test scenario (concentration of thermosensitive pharmaceutical solution in the laboratory) Equipment specifications: Vertical 316L stainless steel vessel body 100, volume 50L, inner wall coated with 0.3mm PTFE anti-stick coating, vacuum pressure -0.1~0.2MPa.

[0049] Core modules: Jacket 110 + built-in coil 120 double-layer heating, heating power 10kW, heat transfer oil medium, temperature control accuracy ±0.5℃; variable frequency anchor scraper agitator, speed 10~30r / min, motor 220, power 2.2kW; rotary vane vacuum pump 300, vacuum degree -0.08~-0.1MPa gauge pressure; shell and tube condenser 400, condensing area 5m², condensing temperature 10℃; preheating coil 700, heat exchange area 3m²; PLC three-parameter linkage control module.

[0050] Operating procedure: The thermosensitive solution of pharmaceutical intermediate (solute concentration 10%, water-soluble, thermosensitive temperature ≥80℃) is preheated to 30℃ via the preheating coil 700 and then injected into the reactor body 100. The vacuum pump 300 is turned on to adjust the vacuum degree to -0.09MPa gauge pressure, the heating module is heated to 60℃, the stirring speed is adjusted to 20r / min, and the condensation recovery module is turned on. The heating power is adjusted in real time through the linkage control of liquid level, temperature and vacuum degree. When the solute concentration reaches 50%, heating and vacuum are automatically stopped, and the discharge valve 130 is opened to complete the discharge. The whole process is continuous and unattended.

[0051] Example 2: Pilot-scale scenario (concentration of precious metal solution in a mine) Equipment specifications: Vertical 316L stainless steel vessel body 100, volume 500L, inner wall coated with 0.4mm PTFE anti-stick coating, vacuum pressure -0.1~0.2MPa.

[0052] Core modules: Jacket 110 + built-in coil 120 double-layer heating, heating power 50kW, steam medium, temperature control accuracy ±0.5℃; variable frequency anchor-type scraper agitator, speed 30~50r / min, motor 220, power 15kW; rotary vane vacuum pump 300, vacuum degree -0.07~-0.09MPa gauge pressure; shell and tube condenser 400, condensing area 20m², condensing temperature 15℃; preheating coil 700, heat exchange area 15m²; PLC three-parameter linkage control + online concentration detection module.

[0053] Operating procedure: The gold-containing precious metal cyanide solution (gold concentration 5g / L, high viscosity, solid content 0.5%) is preheated to 40℃ via a preheating coil 700 and then continuously injected into the reactor 100. The vacuum pump 300 is turned on to adjust the vacuum degree to -0.08MPa gauge pressure, the heating module is heated to 90℃, the stirring speed is adjusted to 40r / min, and the condensation recovery module is turned on. The online concentration detection module monitors the gold concentration in real time. When the gold concentration increases to 50g / L, the discharge speed is automatically adjusted to match the feed speed to achieve 24-hour continuous concentration operation. The recovered cyanide solvent is directly recycled to the leaching process.

[0054] Example 3: Industrial production scenario (concentration of organic solvent solution in fine chemical industry) Equipment specifications: Vertical 316L stainless steel vessel body 100, volume 3000L, inner wall coated with 0.5mm PTFE non-stick coating, vacuum pressure -0.1~0.2MPa, sealing gasket is PTFE-coated fluororubber.

[0055] Core modules: Jacket 110 + built-in coil 120 double-layer heating, heating power 120kW, heat transfer oil medium, temperature control accuracy ±0.5℃; variable frequency anchor scraper agitator, speed 20~60r / min, motor 220, power 30kW; Roots water ring vacuum unit, vacuum degree -0.09~-0.1MPa gauge pressure; shell and tube condenser 400, condensing area 40m², condensing temperature 20℃; preheating coil 700, heat exchange area 30m²; PLC three-parameter linkage control + remote monitoring + inert gas protection module.

[0056] Operating Procedure: The fine chemical organic solvent solution (8% solute concentration, ethanol solvent, highly volatile) is preheated to 35°C via a preheating coil (700°C) and continuously injected into the reactor (100°C). Nitrogen gas is introduced into the reactor for inert gas protection. The vacuum unit is turned on and the vacuum level is adjusted to -0.095MPa gauge pressure. The heating module is heated to 75°C, and the stirring speed is adjusted to 30r / min. The condensation recovery + solvent distillation module is turned on. The operating parameters are monitored in real time via a remote monitoring module. When the solute concentration reaches 60%, the material is automatically discharged. The recovered ethanol solvent is distilled to a purity of 99.9% and can be directly recycled, achieving 7×24h continuous industrial operation.

[0057] To demonstrate the technical effectiveness, the scenarios corresponding to Examples 1, 2, and 3 were used as experimental subjects. The corresponding solutions were treated using the device of this invention and the vacuum-reduced pressure concentrator disclosed in publication number CN204522318U, respectively. The same experimental conditions (solution type, concentration, processing volume, and heating temperature) were set, and the core indicators were tested: solvent recovery rate, concentration efficiency, solute coking decomposition rate, temperature control accuracy, and unit energy consumption. Each experiment was repeated three times, and the average value was taken. The experimental results are shown in Table 1 below: Table 1

[0058] As can be seen from Table 1 above, this device, through jacketed double-layer heating with built-in coil, anchor-type wall scraping and stirring, anti-stick coating, high vacuum sealing, condensation waste heat recovery, and three-parameter linkage control of temperature, liquid level, and vacuum degree, can achieve uniform heating of the entire solution, prevent coking and decomposition, high solvent recovery, precise concentration, and energy saving and consumption reduction, and is suitable for pilot-scale, pilot-scale, and industrial production scenarios.

[0059] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A control method for a solution concentration and evaporation reaction based on an energy-saving heat exchange device, comprising a vertical integrated concentration and evaporation reactor for concentrating and evaporating the solution, wherein the reactor includes a reactor body, a double-layer heating module consisting of a jacket and built-in coils, a variable frequency anchor-type wall scraping and stirring module, a vacuum evaporation module, a condensation recovery module, and a PLC intelligent control module; characterized in that, Includes the following steps: S1. Feed preheating: The solution to be concentrated and dissolved is preheated by the waste heat preheating coil and then fed into the reactor. Feeding is stopped after the set liquid level is reached. S2. Sealing and Vacuum Establishment: Start the anchor scraper agitator. After feeding is completed, close the feed valve and valves of the vessel body and pipeline to establish a sealed environment. Start the vacuum pump to make the vessel reach the set vacuum level and keep it constant. S3, Dual-layer synchronous heating: The jacket and built-in coil dual-layer heating module are activated to simultaneously heat the solution in the kettle, while the anchor-type scraper stirring continuously refreshes the heating surface of the liquid. S4. Three-parameter linkage control: The PLC control system collects temperature, liquid level, and vacuum signals in real time, and automatically adjusts the heating power, stirring speed, and vacuum pump load in a closed loop. The PLC control system integrates a temperature sensor, a liquid level sensor, a vacuum sensor, and an online concentration detection unit, and executes the following linkage logic: automatically increasing heating power and vacuum when the liquid level decreases; automatically adjusting heating power and stirring speed when the temperature exceeds the set range; automatically adjusting vacuum pump load when the vacuum fluctuates; and automatically stopping heating, breaking the vacuum, and discharging material when the concentration reaches the set value. S5. Concentration Evaporation and Solvent Recovery: While S3 and S4 are being carried out, the solution is heated and vaporized. The solvent vapor enters the condensation and recovery module, is condensed into liquid and recovered. The residual heat from condensation is used to preheat the feed solution. S6. Concentration endpoint control: When the online concentration detection or liquid level signal reaches the set concentration endpoint, heating is stopped, stirring and condensation are maintained, and then the vacuum is broken to restore normal pressure; S7. Discharge and cleaning: Open the discharge valve to discharge the concentrate.

2. The control method for solution concentration and evaporation reaction based on an energy-saving heat exchange device according to claim 1, characterized in that: In step S1, the waste heat preheating coil is connected in series with the feed pipeline, and the waste heat from the condensation recovery module is used as a heat source to preheat the solution; when the liquid level in the reactor reaches the set range, the feeding is stopped.

3. The control method for the concentration and evaporation reaction of the solution based on an energy-saving heat exchange device according to claim 2, characterized in that: In step S2, the vessel body is sealed using a combination of a quick-connect flange and a double-layer sealing gasket; the vacuum level is adjusted to -0.07 to -0.1 MPa and kept constant, and the vacuum sensor provides real-time feedback to the PLC to adjust the vacuum pump load.

4. The control method for solution concentration and evaporation reaction based on an energy-saving heat exchange device according to claim 3, characterized in that: In step S3, the jacket covers the outer wall of the vessel, and the built-in coil extends into the liquid inside the vessel. The jacket and the built-in coil are connected in parallel to the same heat source and are heated and stopped synchronously. The outer edge of the blade of the anchor-type wall-scraping agitator is provided with a polytetrafluoroethylene wall-scraping strip. The gap between the wall-scraping strip and the inner wall of the vessel is ≤5mm. The wall-scraping strip continuously scrapes off the material adhering to the inner wall and the surface of the coil.

5. The control method for the concentration and evaporation reaction of the solution based on an energy-saving heat exchange device according to claim 4, characterized in that: In step S4, when the temperature exceeds the set range, the PLC prioritizes adjusting the heating power; when the heating power is adjusted to the limit and still exceeds the set range, the stirring speed is then adjusted; in step S6, after reaching the concentration endpoint, stirring and condensation are maintained for 3-5 minutes, and then the vacuum is broken to restore normal pressure.

6. A solution concentration and evaporation reactor based on an energy-saving heat exchange device, wherein the process is carried out using the control method for solution concentration and evaporation reaction based on an energy-saving heat exchange device as described in claim 5, characterized in that... include: The vessel body has a steam port at the top, a vacuum port on the side, and a discharge valve at the bottom; The double-layer heating module includes a jacket covering the outer wall of the vessel and an internal coil spirally arranged on the outer wall of the vessel. The jacket and the internal coil are connected in parallel to the same heat source. The stirring module includes a frequency-controlled anchor-type wall-scraping stirring device vertically installed at the center of the vessel body. The outer edge of the stirring paddle is provided with a polytetrafluoroethylene wall-scraping strip, and the gap between the wall-scraping strip and the inner wall of the vessel body is ≤5mm. The vacuum evaporation module includes a vacuum pump and a vacuum sensor, and is connected to the vacuum port of the vessel. The condensation recovery module includes a condenser and a solvent storage tank connected to the steam port of the reactor body, and is equipped with a waste heat preheating coil connected in series with the feed pipeline. The PLC intelligent control module integrates temperature sensors, liquid level sensors, and vacuum sensors, and is connected to the double-layer heating module, stirring module, and vacuum evaporation module respectively to achieve linkage control of three parameters: temperature, liquid level, and vacuum.

7. The solution concentration and evaporation reactor based on an energy-saving heat exchange device according to claim 6, characterized in that: The vessel body seal adopts a double-layer sealing structure consisting of a quick-install flange and a fluororubber gasket or a PTFE-coated fluororubber gasket; the inner wall of the vessel body is coated with a polytetrafluoroethylene non-stick coating, and the vessel body adopts a detachable or quick-release structure.

8. The solution concentration and evaporation reactor based on an energy-saving heat exchange device according to claim 7, characterized in that: The condenser of the condensation recovery module is a shell-and-tube condenser or a plate heat exchanger, and the condenser is connected to the solvent storage tank; the waste heat preheating coil is wound or connected in series with the feed pipeline to preheat the feed solution using the waste heat from condensation.

9. The solution concentration and evaporation reactor based on an energy-saving heat exchange device according to claim 8, characterized in that: The PLC intelligent control module also includes an online concentration detection unit, configured to perform the following linkage control: increase heating power and vacuum degree when the liquid level drops; adjust heating power and stirring speed when the temperature exceeds the tolerance; adjust vacuum pump load when the vacuum fluctuates; stop heating, break vacuum and discharge material when the concentration reaches the standard.

10. The solution concentration and evaporation reactor based on an energy-saving heat exchange device according to claim 9, characterized in that: It also includes one or more of the following: An inert gas protection module is used to fill the vessel with nitrogen or argon gas; The CIP cleaning module integrates a high-pressure cleaning nozzle and a cleaning fluid circulation system. The remote monitoring and fault alarm module is used to remotely view operating parameters and realize remote start / stop and fault alarm. The solvent distillation module, connected in series with the condensation recovery module, is used to purify the recovered solvent by distillation. The vacuum pump of the vacuum evaporation module is a Roots water ring vacuum unit.

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