A method for treating MVR evaporator waste liquid based on physical property separation

Abstract

The present invention discloses a method for treating waste liquid of an MVR evaporator based on physical property separation, which relates to the technical field of solvent distillation and recovery, including: using a three-phase separator to filter and remove floating oil and solid impurities in the waste liquid through gravity sedimentation, cyclone separation and demulsification treatment; inputting the filtered waste liquid into a shell and tube heat exchanger to preheat the waste liquid entering the distillation host; using a compressor driven by an internal motor to heat the air and perform heat exchange on the waste liquid in the stainless steel distillation host; using a two-component online cleaning unit to automatically clean the distillation host; inputting the water vapor obtained by evaporation into a blade demister; inputting the heat released during the condensation process into the distillation host for recycling; using an automatic control system to collect and control the internal mechanical operating parameters of the evaporator in real time. Through the mechanical vapor compression technology, the thermal energy recycling of the secondary steam in the wastewater is realized, which greatly reduces the energy consumption.

Description

Technical Field

[0001] The invention relates to the technical field of solvent distillation recovery, and in particular to a method for treating MVR evaporator waste liquid based on physical property separation. Background Art

[0002] MVR evaporator is the abbreviation of mechanical vapor recompression evaporator. Its working principle is to use a high-efficiency steam compressor to compress the secondary steam generated by evaporation, increase the pressure and temperature of the secondary steam, and then re-inject the secondary steam with increased thermal energy into the heater to heat the original liquid. In this way, the heated original liquid will continue to evaporate and produce more secondary steam, thereby achieving a continuous evaporation state. The core of MVR technology is to use the thermal enthalpy of secondary steam to increase its temperature as a heat source by compressing it to replace fresh steam, thereby reducing dependence on external energy and achieving energy saving effects.

[0003] Many industrial wastewaters, such as coal chemical wastewater, shale gas wastewater, electroplating wastewater, etc., contain high concentrations of refractory organic matter, inorganic salts, heavy metals and other pollutants, making them difficult to treat. Traditional wastewater treatment methods often consume a lot of energy and produce secondary pollution. Summary of the invention

[0004] In order to solve the above technical problems, a method for treating MVR evaporator waste liquid based on physical property separation is provided. This technical solution solves the problems raised in the above background technology.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A method for treating MVR evaporator waste liquid based on physical property separation, comprising:

[0007] Based on the principle of physical separation, a three-phase separator is used to filter and remove floating oil and solid impurities in the waste liquid through gravity sedimentation, cyclone separation and demulsification treatment;

[0008] The filtered waste liquid is input into the shell and tube heat exchanger to preheat the waste liquid entering the distillation host to reach the preset temperature and reduce the heat load inside the evaporator;

[0009] The compressor driven by the internal motor heats the air and exchanges heat with the waste liquid in the stainless steel distillation main unit, evaporating the liquid water in the waste liquid into water vapor;

[0010] Based on acidic and alkaline cleaning agents, a two-component online cleaning unit is used to automatically clean the distillation host;

[0011] The evaporated water vapor is input into the blade demister to remove the tiny droplets carried in the gas;

[0012] The demisted steam is sequentially input into the steam cooler and the steam compressor, the heat released during the condensation process is input into the distillation host for recycling, and the compressed distilled water is collected in a distilled water collection tank;

[0013] An automatic control system is used to collect and control the internal mechanical operating parameters of the evaporator in real time. The internal machinery of the evaporator includes a three-phase separator, a shell and tube heat exchanger, a distillation main unit, a blade demister, a steam cooler and a steam compressor.

[0014] Preferably, based on the physical separation principle, the three-phase separator is used to filter and remove the floating oil and solid impurities in the waste liquid through gravity sedimentation, cyclone separation and demulsification treatment, which specifically includes:

[0015] When the waste liquid enters the three-phase separator, due to the density differences of different components, gravity and buoyancy will cause them to naturally settle or float;

[0016] Solid impurities will sink to the bottom of the three-phase separator, while liquid will rise to the top;

[0017] Add demulsifier to the three-phase separator to reduce the surface tension of floating oil and make the emulsified oil aggregate into oil droplets;

[0018] The cyclone in the three-phase separator is used to generate a rotating motion;

[0019] By controlling the rotation speed of the cyclone, the components with higher density than water and the components with lower density than water in the waste liquid are separated in the radial direction;

[0020] The components in the waste liquid with a density higher than that of water are thrown toward the wall of the three-phase separator and flow downward along the wall of the three-phase separator;

[0021] Components in the wastewater that are less dense than water converge toward the center and rise;

[0022] The solid impurities, floating oil and water separated in the three-phase separator are discharged through three different outlets respectively.

[0023] Preferably, the step of inputting the filtered waste liquid into a shell and tube heat exchanger, preheating the waste liquid entering the distillation main unit to reach a preset temperature, and reducing the heat load inside the evaporator specifically includes:

[0024] The shell and tube heat exchanger consists of an outer shell and internal pipes, which are arranged in parallel and fixed inside the shell by tube sheets;

[0025] The filtered waste liquid enters the internal piping system from one end of the shell and tube heat exchanger to exchange heat with the preheated steam passing through the shell;

[0026] By controlling the temperature and flow rate of the preheating steam, the waste liquid in the shell and tube heat exchanger is preheated to a preset temperature;

[0027] Wrap the outer wall of the shell and tube heat exchanger with insulation material to control the heat loss of preheated steam;

[0028] Insulating materials are used at the connection points between pipes and valves.

[0029] Preferably, the method of heating the air with a compressor driven by an internal motor and exchanging heat with the waste liquid in the stainless steel distillation main unit to evaporate the liquid water in the waste liquid into water vapor specifically includes:

[0030] The compressor driven by the motor inside the distillation main unit compresses the gas, increasing the pressure and temperature of the gas;

[0031] During the compression process, the distance between gas molecules decreases, collisions between them increase, and the temperature rises;

[0032] The heated air is introduced into the heat exchange area of ​​the stainless steel distillation main unit to exchange heat with the input waste liquid;

[0033] During the heat exchange process, the waste liquid absorbs heat from the air and its temperature rises;

[0034] When the temperature of the waste liquid reaches the boiling point of water, the liquid water begins to evaporate into water vapor;

[0035] The evaporation process continues;

[0036] A temperature sensor is installed at the output end of the compressor and the output end of the distillation host respectively to monitor the temperature change of the heated air in real time;

[0037] Determine whether the air temperature change is less than the preset temperature difference. If so, the evaporation process is terminated and the water in the output waste liquid has been completely evaporated. If not, no output is made.

[0038] Preferably, the automatic cleaning process of the distillation host using a two-component online cleaning unit based on the two cleaning agents of acidity and alkalinity specifically includes:

[0039] Preset cleaning intervals;

[0040] Determine whether the working time of the distillation host reaches the cleaning time interval. If so, suspend the working of the distillation host, spray the acid cleaning agent and alkaline cleaning agent to the steam pipe and equipment surface through the spray device in turn, and re-time the working time of the distillation host. If not, no output is made;

[0041] Acidic cleaning agents are used to remove acidic dirt in steam pipes and equipment, including metal oxides and scale;

[0042] Alkaline cleaning agents are used to remove alkaline dirt, including grease and organic matter;

[0043] After cleaning is completed, the steam pipes and equipment are flushed and drained to remove residual cleaning agents and dirt.

[0044] Preferably, the step of inputting the evaporated water vapor into a blade-type demister to remove the tiny droplets carried in the gas specifically comprises:

[0045] The water vapor containing tiny droplets is introduced into the inlet of the vane demister;

[0046] Water vapor passes through at least one blade inside the demister. When the gas passes through the blade, tiny droplets are trapped on the blade surface due to inertial force;

[0047] As the water vapor flows, tiny droplets accumulate on the leaves and grow in size;

[0048] Under the action of gravity, the droplets captured on the blades will slide down the blades to the droplet collection device at the bottom of the demister;

[0049] A flow meter is installed at the entrance of the demister, and the flow rate of the water vapor input into the demister is monitored in real time by the flow meter;

[0050] Obtain blade related parameters, wherein the blade related parameters include blade mass, blade maximum bearing mass, blade effective area, blade radius, and blade drag coefficient;

[0051] Based on the flow rate of the input water vapor, the resistance force on the blade is calculated using the resistance formula;

[0052] Use the centrifugal force formula to calculate the centrifugal force generated by the blades;

[0053] By balancing the forces, the resistance on the blade is made equal to the centrifugal force generated by the blade, and the optimal rotation speed of the blade is calculated;

[0054] The resistance formula is: ,

[0055] In the formula, is the resistance of the blade, is the blade drag coefficient, is the water vapor density, is the flow rate of water vapor input to the demister, is the effective area of ​​the blade;

[0056] The centrifugal force formula is: ,

[0057] In the formula, is the centrifugal force generated by the blades, is the blade mass, is the maximum bearing mass of the blade, is the blade speed, is the blade radius.

[0058] Preferably, the step of sequentially inputting the demisted steam into a steam cooler and a steam compressor, inputting the heat released during the condensation process into a distillation host for recycling, and using a distilled water collection tank to collect the compressed distilled water specifically comprises:

[0059] The demisted steam is fed into the steam cooler to reduce the temperature of the steam through heat exchange, so that it reaches a state suitable for entering the steam compressor;

[0060] The heat difference generated by steam cooling is used to heat the air in the steam cooler and input into the shell and tube heat exchanger as preheated steam;

[0061] The cooled steam is input into the steam compressor, and the steam pressure is increased by the mechanical action of the steam compressor, so that the water vapor is liquefied into distilled water;

[0062] During the steam compression process, water vapor liquefies and releases heat, which is input into the distillation main unit to heat the waste liquid;

[0063] A distilled water collection tank is used to collect the compressed distilled water.

[0064] Preferably, the use of an automatic control system to collect and control the internal mechanical operating parameters of the evaporator in real time specifically includes:

[0065] A flow meter is installed at the entrance of the three-phase separator, and the speed of the cyclone is controlled by the automatic control system to increase or decrease in proportion to the flow meter reading;

[0066] Real-time monitoring of temperature and pressure parameters of the shell and tube heat exchanger, and automatic adjustment of heating power and flow rate based on the parameters;

[0067] A temperature sensor is installed at the output end of the compressor and the output end of the distillation host respectively to monitor the temperature change of the heated air in real time and automatically control the working state of the distillation host based on the temperature change;

[0068] A flow meter is installed at the entrance of the demister, and the flow rate of the water vapor input to the demister is monitored in real time by the flow meter, and the blade speed is automatically controlled based on the water vapor flow rate;

[0069] Install a temperature sensor at the inlet of the steam desuperheater and set the maximum and minimum inlet steam temperature;

[0070] Determine whether the temperature sensor reading is greater than the maximum value of the inlet steam. If so, increase the flow of cooling air and increase the pressure of the steam compressor. If not, no output is made.

[0071] Determine whether the temperature sensor reading is less than the minimum value of the inlet steam. If so, reduce the flow rate of cooling air and reduce the pressure of the steam compressor. If not, no output is made.

[0072] Compared with the prior art, the present invention has the following beneficial effects:

[0073] It can effectively remove pollutants, achieve standard discharge of wastewater or recycling of resources, and utilize mechanical steam compression technology to achieve thermal energy recycling of secondary steam in wastewater, reducing the demand for external energy, thereby reducing the cost of wastewater treatment, greatly reducing energy consumption, and reducing the emission of chemical pollutants. It meets environmental protection requirements and has broad application prospects and significant social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 The flowchart of the MVR evaporator waste liquid treatment method based on physical property separation of the present invention;

[0075] Figure 2 The present invention is a flow chart of the method for filtering and removing floating oil and solid impurities in waste liquid;

[0076] Figure 3 This is a flow chart of the method for preheating the waste liquid entering the distillation main unit of the present invention;

[0077] Figure 4 This is a flow chart of a method for heating air with a compressor driven by an internal motor and exchanging heat with waste liquid in a stainless steel distillation mainframe of the present invention;

[0078] Figure 5 This is a flow chart of a method for automatically cleaning a distillation host using a two-component online cleaning unit according to the present invention;

[0079] Figure 6 This is a flow chart of the method for removing tiny liquid droplets carried in gas according to the present invention;

[0080] Figure 7 This is a flow chart of the method for inputting the heat released during the condensation process into the distillation host for recycling according to the present invention;

[0081] Figure 8 This is a flow chart of a method for collecting and controlling the internal mechanical operating parameters of an evaporator in real time using an automatic control system according to the present invention. DETAILED DESCRIPTION

[0082] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0083] Reference Figure 1 As shown, a method for treating MVR evaporator waste liquid based on physical property separation comprises:

[0084] Based on the principle of physical separation, a three-phase separator is used to filter and remove floating oil and solid impurities in the waste liquid through gravity sedimentation, cyclone separation and demulsification treatment;

[0085] The filtered waste liquid is input into the shell and tube heat exchanger to preheat the waste liquid entering the distillation host to reach the preset temperature and reduce the heat load inside the evaporator;

[0086] The compressor driven by the internal motor heats the air and exchanges heat with the waste liquid in the stainless steel distillation main unit, evaporating the liquid water in the waste liquid into water vapor;

[0087] Based on acidic and alkaline cleaning agents, a two-component online cleaning unit is used to automatically clean the distillation host;

[0088] The evaporated water vapor is input into the blade demister to remove the tiny droplets carried in the gas;

[0089] The demisted steam is sequentially input into the steam cooler and the steam compressor, the heat released during the condensation process is input into the distillation host for recycling, and the compressed distilled water is collected in a distilled water collection tank;

[0090] An automatic control system is used to collect and control the internal mechanical operating parameters of the evaporator in real time. The internal machinery of the evaporator includes a three-phase separator, a shell and tube heat exchanger, a distillation main unit, a blade demister, a steam cooler and a steam compressor.

[0091] Reference Figure 2 As shown, based on the principle of physical separation, the three-phase separator is used to filter and remove floating oil and solid impurities in the waste liquid through gravity sedimentation, cyclone separation and demulsification treatment, specifically including:

[0092] When the waste liquid enters the three-phase separator, due to the density differences of different components, gravity and buoyancy will cause them to naturally settle or float;

[0093] Solid impurities will sink to the bottom of the three-phase separator, while liquid will rise to the top;

[0094] Add demulsifier to the three-phase separator to reduce the surface tension of floating oil and make the emulsified oil aggregate into oil droplets;

[0095] The cyclone in the three-phase separator is used to generate a rotating motion;

[0096] By controlling the rotation speed of the cyclone, the components with higher density than water and the components with lower density than water in the waste liquid are separated in the radial direction;

[0097] The components in the waste liquid with a density higher than that of water are thrown toward the wall of the three-phase separator and flow downward along the wall of the three-phase separator;

[0098] Components in the wastewater that are less dense than water converge toward the center and rise;

[0099] The solid impurities, floating oil and water separated in the three-phase separator are discharged through three different outlets respectively.

[0100] The inlet section should be designed with sufficient flow rate and flow channel shape to ensure that the raw liquid can enter the separator evenly and stably. At the same time, the inlet section can also be equipped with a guide plate or a cyclone to guide the raw liquid to produce swirling motion and improve the separation efficiency; in the bottom liquid-liquid separation section, oil and water are separated due to different densities. The oil phase will float on the upper layer, while the water phase will sink to the lower layer. In order to ensure the effect of liquid-liquid separation, the bottom should be designed with appropriate sedimentation space and separation plate structures; the separated solid impurities, oil and water are discharged through different outlets respectively.

[0101] Reference Figure 3 As shown, the filtered waste liquid is input into the shell and tube heat exchanger to preheat the waste liquid entering the distillation host to reach a preset temperature and reduce the heat load inside the evaporator. Specifically, it includes:

[0102] The shell and tube heat exchanger consists of an outer shell and internal pipes, which are arranged in parallel and fixed inside the shell by tube sheets;

[0103] The filtered waste liquid enters the internal piping system from one end of the shell and tube heat exchanger to exchange heat with the preheated steam passing through the shell;

[0104] By controlling the temperature and flow rate of the preheating steam, the waste liquid in the shell and tube heat exchanger is preheated to a preset temperature;

[0105] Wrap the outer wall of the shell and tube heat exchanger with insulation material to control the heat loss of preheated steam;

[0106] Insulating materials are used at the connection points between pipes and valves.

[0107] The preheating system should be able to transfer heat efficiently to ensure that the waste liquid reaches the required temperature in a short time; the preheating system should have good stability and be able to provide preheating function continuously and stably to avoid affecting the normal operation of the evaporator due to temperature fluctuations; the design of the preheating system should fully consider energy-saving factors, and reduce energy consumption during the preheating process by optimizing structural design and selecting high-efficiency energy-saving equipment.

[0108] Reference Figure 4 As shown, a compressor driven by an internal motor is used to heat the air and to exchange heat with the waste liquid in the stainless steel distillation main unit to evaporate the liquid water in the waste liquid into water vapor. Specifically, the process includes:

[0109] The compressor driven by the motor inside the distillation main unit compresses the gas, increasing the pressure and temperature of the gas;

[0110] During the compression process, the distance between gas molecules decreases, collisions between them increase, and the temperature rises;

[0111] The heated air is introduced into the heat exchange area of ​​the stainless steel distillation main unit to exchange heat with the input waste liquid;

[0112] During the heat exchange process, the waste liquid absorbs heat from the air and its temperature rises;

[0113] When the temperature of the waste liquid reaches the boiling point of water, the liquid water begins to evaporate into water vapor;

[0114] The evaporation process continues;

[0115] A temperature sensor is installed at the output end of the compressor and the output end of the distillation host respectively to monitor the temperature change of the heated air in real time;

[0116] Determine whether the air temperature change is less than the preset temperature difference. If so, the evaporation process is terminated and the water in the output waste liquid has been completely evaporated. If not, no output is made.

[0117] The compressor should be able to efficiently convert the energy of steam, improve compression efficiency and reduce energy consumption; the structural design should ensure that the steam compressor can remain stable during operation to avoid performance degradation due to problems such as vibration or wear; since steam may contain corrosive substances, the compressor material should have good corrosion resistance, so stainless steel is selected; the structural design should be easy to disassemble, clean and maintain to reduce maintenance costs and increase the service life of the equipment.

[0118] Reference Figure 5 As shown, based on the two cleaning agents, acidic and alkaline, the two-component online cleaning unit is used to automatically clean the distillation host, including:

[0119] Preset cleaning intervals;

[0120] Determine whether the working time of the distillation host reaches the cleaning time interval. If so, suspend the working of the distillation host, spray the acid cleaning agent and alkaline cleaning agent to the steam pipe and equipment surface through the spray device in turn, and re-time the working time of the distillation host. If not, no output is made;

[0121] Acidic cleaning agents are used to remove acidic dirt in steam pipes and equipment, including metal oxides and scale;

[0122] Alkaline cleaning agents are used to remove alkaline dirt, including grease and organic matter;

[0123] After cleaning is completed, the steam pipes and equipment are flushed and drained to remove residual cleaning agents and dirt.

[0124] Before cleaning, it is necessary to check the status of the steam pipes and equipment to ensure that they can withstand the pressure and temperature changes during the cleaning process; connect the two-component online cleaning unit to the steam pipes and equipment to ensure that the cleaning agent can be smoothly transported to the cleaning area; set the usage, injection pressure, and cleaning time parameters of the cleaning unit according to the cleaning requirements and the properties of the cleaning agent.

[0125] Reference Figure 6 As shown, the evaporated water vapor is input into the blade demister to remove the tiny droplets carried in the gas, specifically including:

[0126] The water vapor containing tiny droplets is introduced into the inlet of the vane demister;

[0127] Water vapor passes through at least one blade inside the demister. When the gas passes through the blade, tiny droplets are trapped on the blade surface due to inertial force;

[0128] As the water vapor flows, tiny droplets accumulate on the leaves and grow in size;

[0129] Under the action of gravity, the droplets captured on the blades will slide down the blades to the droplet collection device at the bottom of the demister;

[0130] A flow meter is installed at the entrance of the demister, and the flow rate of the water vapor input into the demister is monitored in real time by the flow meter;

[0131] Obtain blade related parameters, wherein the blade related parameters include blade mass, blade maximum bearing mass, blade effective area, blade radius, and blade drag coefficient;

[0132] Based on the flow rate of the input water vapor, the resistance force on the blade is calculated using the resistance formula;

[0133] Use the centrifugal force formula to calculate the centrifugal force generated by the blades;

[0134] By balancing the forces, the resistance on the blade is made equal to the centrifugal force generated by the blade, and the optimal rotation speed of the blade is calculated;

[0135] The resistance formula is: ,

[0136] In the formula, is the resistance of the blade, is the blade drag coefficient, is the water vapor density, is the flow rate of water vapor input to the demister, is the effective area of ​​the blade;

[0137] The centrifugal force formula is: ,

[0138] In the formula, is the centrifugal force generated by the blades, is the blade mass, is the maximum bearing mass of the blade, is the blade speed, is the blade radius.

[0139] As a key component, the structural design of the demister is also crucial. The main function of the demister is to remove tiny droplets carried in the evaporator outlet gas to ensure that the discharged gas meets environmental protection requirements and prevent the droplets from corroding or clogging subsequent equipment.

[0140] Reference Figure 7 As shown, the demisted steam is sequentially input into the steam cooler and the steam compressor, the heat released during the condensation process is input into the distillation host for recycling, and the compressed distilled water is collected in a distilled water collection tank. Specifically, it includes:

[0141] The demisted steam is fed into the steam cooler to reduce the temperature of the steam through heat exchange, so that it reaches a state suitable for entering the steam compressor;

[0142] The heat difference generated by steam cooling is used to heat the air in the steam cooler and input into the shell and tube heat exchanger as preheated steam;

[0143] The cooled steam is input into the steam compressor, and the steam pressure is increased by the mechanical action of the steam compressor, so that the water vapor is liquefied into distilled water;

[0144] During the steam compression process, water vapor liquefies and releases heat, which is input into the distillation main unit to heat the waste liquid;

[0145] A distilled water collection tank is used to collect the compressed distilled water.

[0146] The basic principle of MVR technology is to use a compressor to increase the pressure and temperature of secondary steam, thereby increasing its latent heat so that it can be reused as heating steam. In this process, the potential energy of secondary steam is effectively recycled, reducing the consumption of external steam, achieving energy conservation and environmental friendliness.

[0147] Reference Figure 8 As shown, the automatic control system is used to collect and control the internal mechanical operating parameters of the evaporator in real time, including:

[0148] A flow meter is installed at the entrance of the three-phase separator, and the speed of the cyclone is controlled by the automatic control system to increase or decrease in proportion to the flow meter reading;

[0149] Real-time monitoring of temperature and pressure parameters of the shell and tube heat exchanger, and automatic adjustment of heating power and flow rate based on the parameters;

[0150] A temperature sensor is installed at the output end of the compressor and the output end of the distillation host respectively to monitor the temperature change of the heated air in real time and automatically control the working state of the distillation host based on the temperature change;

[0151] A flow meter is installed at the entrance of the demister, and the flow rate of the water vapor input to the demister is monitored in real time by the flow meter, and the blade speed is automatically controlled based on the water vapor flow rate;

[0152] Install a temperature sensor at the inlet of the steam desuperheater and set the maximum and minimum inlet steam temperature;

[0153] Determine whether the temperature sensor reading is greater than the maximum value of the inlet steam. If so, increase the flow of cooling air and increase the pressure of the steam compressor. If not, no output is made.

[0154] Determine whether the temperature sensor reading is less than the minimum value of the inlet steam. If so, reduce the flow rate of cooling air and reduce the pressure of the steam compressor. If not, no output is made.

[0155] The automatic control system collects and accurately controls the internal mechanical operating parameters of the evaporator in real time to maintain stable distillation and improve the quality of distilled water. It also uses bus technology to transmit operating parameter signals and has good scalability and maintainability.

[0156] Furthermore, the present solution also proposes a computer-readable storage medium on which a computer-readable program is stored. When the computer-readable program is called, the above-mentioned MVR evaporator waste liquid treatment method based on physical property separation is executed.

[0157] It is understandable that the storage medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; an optical medium, such as a DVD; or a semiconductor medium, such as a solid state drive (SSD).

[0158] In summary, the advantages of the present invention are: it can effectively remove pollutants, achieve standard discharge of wastewater or recycling of resources, utilize mechanical steam compression technology to achieve thermal energy recycling of secondary steam in wastewater, reduce the demand for external energy, thereby reducing the cost of wastewater treatment, greatly reducing energy consumption, reducing the emission of chemical pollutants, meeting environmental protection requirements, and having broad application prospects and significant social and economic benefits.

[0159] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for treating MVR evaporator waste liquid based on physical property separation, characterized in that: include: Based on the principle of physical separation, a three-phase separator is used to filter and remove floating oil and solid impurities in the waste liquid through gravity sedimentation, cyclone separation and demulsification treatment; The filtered waste liquid is input into the shell and tube heat exchanger to preheat the waste liquid entering the distillation host to reach the preset temperature and reduce the heat load inside the evaporator; The compressor driven by the internal motor heats the air and exchanges heat with the waste liquid in the stainless steel distillation main unit, evaporating the liquid water in the waste liquid into water vapor; Based on acidic and alkaline cleaning agents, a two-component online cleaning unit is used to automatically clean the distillation host; The evaporated water vapor is input into the blade demister to remove the tiny droplets carried in the gas, including: The water vapor containing tiny droplets is introduced into the inlet of the vane demister; Water vapor passes through at least one blade inside the demister. When the gas passes through the blade, tiny droplets are trapped on the blade surface due to inertial force; As the water vapor flows, tiny droplets accumulate on the leaves and grow in size; Under the action of gravity, the droplets captured on the blades will slide down the blades to the droplet collection device at the bottom of the demister; A flow meter is installed at the entrance of the demister, and the flow rate of the water vapor input into the demister is monitored in real time by the flow meter; Obtain blade related parameters, wherein the blade related parameters include blade mass, blade maximum bearing mass, blade effective area, blade radius, and blade drag coefficient; Based on the flow rate of the input water vapor, the resistance force on the blade is calculated using the resistance formula; Use the centrifugal force formula to calculate the centrifugal force generated by the blades; By balancing the forces, the resistance on the blade is made equal to the centrifugal force generated by the blade, and the optimal rotation speed of the blade is calculated; The resistance formula is: , In the formula, is the resistance of the blade, is the blade drag coefficient, is the water vapor density, is the flow rate of water vapor input to the demister, is the effective area of ​​the blade; The centrifugal force formula is: , In the formula, is the centrifugal force generated by the blades, is the blade mass, is the maximum bearing mass of the blade, is the blade speed, is the blade radius; The demisted steam is sequentially input into the steam cooler and the steam compressor, the heat released during the condensation process is input into the distillation host for recycling, and the compressed distilled water is collected in a distilled water collection tank; Use the automatic control system to collect and control the internal mechanical operating parameters of the evaporator in real time, including: A flow meter is installed at the entrance of the three-phase separator, and the speed of the cyclone is controlled by the automatic control system to increase or decrease in proportion to the flow meter reading; A temperature sensor is installed at the output end of the compressor and the output end of the distillation host respectively to monitor the temperature change of the heated air in real time and automatically control the working state of the distillation host based on the temperature change; A flow meter is installed at the entrance of the demister, and the flow rate of the water vapor input to the demister is monitored in real time by the flow meter, and the blade speed is automatically controlled based on the water vapor flow rate; The internal machinery of the evaporator includes a three-phase separator, a shell and tube heat exchanger, a distillation main unit, a blade demister, a steam cooler and a steam compressor.

2. The method for treating MVR evaporator waste liquid based on physical property separation according to claim 1, characterized in that: Based on the physical separation principle, the three-phase separator is used to filter and remove the floating oil and solid impurities in the waste liquid through gravity sedimentation, cyclone separation and demulsification treatment, which specifically includes: When the waste liquid enters the three-phase separator, due to the density differences of different components, gravity and buoyancy will cause them to naturally settle or float; Solid impurities will sink to the bottom of the three-phase separator, while liquid will rise to the top; Add demulsifier to the three-phase separator to reduce the surface tension of floating oil and make the emulsified oil aggregate into oil droplets; The cyclone in the three-phase separator is used to generate a rotating motion; By controlling the rotation speed of the cyclone, the components with higher density than water and the components with lower density than water in the waste liquid are separated in the radial direction; The components in the waste liquid with a density higher than that of water are thrown toward the wall of the three-phase separator and flow downward along the wall of the three-phase separator; Components in the wastewater that are less dense than water converge toward the center and rise; The solid impurities, floating oil and water separated in the three-phase separator are discharged through three different outlets respectively.

3. The method for treating MVR evaporator waste liquid based on physical property separation according to claim 2, characterized in that: The step of inputting the filtered waste liquid into the shell and tube heat exchanger, preheating the waste liquid entering the distillation main unit to reach a preset temperature, and reducing the heat load inside the evaporator specifically includes: The shell and tube heat exchanger consists of an outer shell and internal pipes, which are arranged in parallel and fixed inside the shell by tube sheets; The filtered waste liquid enters the internal piping system from one end of the shell and tube heat exchanger to exchange heat with the preheated steam passing through the shell; By controlling the temperature and flow rate of the preheating steam, the waste liquid in the shell and tube heat exchanger is preheated to a preset temperature; Wrap the outer wall of the shell and tube heat exchanger with insulation material to control the heat loss of preheated steam; Insulating materials are used at the connection points between pipes and valves.

4. The method for treating MVR evaporator waste liquid based on physical property separation according to claim 3, characterized in that: The method of heating the air with a compressor driven by an internal motor and exchanging heat with the waste liquid in the stainless steel distillation main unit to evaporate the liquid water in the waste liquid into water vapor specifically includes: The compressor driven by the motor inside the distillation main unit compresses the gas, increasing the pressure and temperature of the gas; During the compression process, the distance between gas molecules decreases, collisions between them increase, and the temperature rises; The heated air is introduced into the heat exchange area of ​​the stainless steel distillation main unit to exchange heat with the input waste liquid; During the heat exchange process, the waste liquid absorbs heat from the air and its temperature rises; When the temperature of the waste liquid reaches the boiling point of water, the liquid water begins to evaporate into water vapor; The evaporation process continues; A temperature sensor is installed at the output end of the compressor and the output end of the distillation host respectively to monitor the temperature change of the heated air in real time; Determine whether the air temperature change is less than the preset temperature difference. If so, the evaporation process is terminated and the water in the output waste liquid has been completely evaporated. If not, no output is made.

5. The method for treating MVR evaporator waste liquid based on physical property separation according to claim 4, characterized in that: The automatic cleaning process of the distillation host using a two-component online cleaning unit based on the two cleaning agents of acidity and alkalinity specifically includes: Preset cleaning intervals; Determine whether the working time of the distillation host reaches the cleaning time interval. If so, suspend the working of the distillation host, spray the acid cleaning agent and alkaline cleaning agent to the steam pipe and equipment surface through the spray device in turn, and re-time the working time of the distillation host. If not, no output is made; Acid cleaners are used to remove acidic scale from steam pipes and equipment; Alkaline cleaning agents are used to remove alkaline dirt; After cleaning is completed, the steam pipes and equipment are flushed and drained to remove residual cleaning agents and dirt.

6. The method for treating MVR evaporator waste liquid based on physical property separation according to claim 5, characterized in that: The step of sequentially inputting the demisted steam into a steam cooler and a steam compressor, inputting the heat released during the condensation process into a distillation host for recycling, and using a distilled water collection tank to collect the compressed distilled water specifically includes: The demisted steam is fed into the steam cooler to reduce the temperature of the steam through heat exchange, so that it reaches a state suitable for entering the steam compressor; The heat difference generated by steam cooling is used to heat the air in the steam cooler and input into the shell and tube heat exchanger as preheated steam; The cooled steam is input into the steam compressor, and the steam pressure is increased by the mechanical action of the steam compressor, so that the water vapor is liquefied into distilled water; During the steam compression process, water vapor liquefies and releases heat, which is input into the distillation main unit to heat the waste liquid; A distilled water collection tank is used to collect the compressed distilled water.

7. The method for treating MVR evaporator waste liquid based on physical property separation according to claim 6, characterized in that: The use of the automatic control system to collect and control the internal mechanical operating parameters of the evaporator in real time specifically includes: Real-time monitoring of temperature and pressure parameters of the shell and tube heat exchanger, and automatic adjustment of heating power and flow rate based on the parameters; Install a temperature sensor at the inlet of the steam desuperheater and set the maximum and minimum inlet steam temperature; Determine whether the temperature sensor reading is greater than the maximum value of the inlet steam. If so, increase the flow of cooling air and increase the pressure of the steam compressor. If not, no output is made. Determine whether the temperature sensor reading is less than the minimum value of the inlet steam. If so, reduce the flow rate of cooling air and reduce the pressure of the steam compressor. If not, no output is made.

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