Low-cost high-efficiency calcium hydroxide purification method and process based on temperature regulation and control

Abstract

The invention provides a low-cost high-efficiency calcium hydroxide purification method and process based on temperature regulation and control, and relates to the technical field of sodium hydroxide preparation, refined temperature control and zoned heating are adopted, the temperature of each heating zone is monitored in real time according to volatilization points and decomposition temperatures of different impurities, it is ensured that the temperature of each stage accurately reaches a set value, and the purification efficiency is improved. A PI D control algorithm is adopted to adjust the heating power, overheating or insufficiency is avoided, the purity of calcium hydroxide is ensured, an energy recovery system recovers waste heat generated in the reaction process through a heat exchanger and is used for preheating raw materials in other stages, energy consumption is effectively reduced, a low-temperature area, a medium-temperature area and a high-temperature area are set, and energy consumption is reduced. According to physical and chemical properties of impurities, staged heating treatment is performed, the purification process is dynamically optimized through intelligent process control in combination with AI and machine learning technologies and process parameters, automation and intelligence of the purification process are ensured, AI performs modeling through historical data, continuous optimization and learning are performed, the purification effect is improved, and the reaction rate is increased.

Description

Technical Field

[0001] The invention relates to the technical field of sodium hydroxide preparation, and in particular to a low-cost and efficient calcium hydroxide purification method and process based on temperature control. Background Art

[0002] According to a process production line and process method for preparing caustic soda disclosed in Chinese patent number "CN114291825A", alkali liquor with a concentration of 32% is used as a raw material and is put into a second-effect evaporator. After the second-effect evaporation treatment, it enters a first-effect evaporator for first-effect evaporation; the alkali liquor coming out of the first-effect evaporator is divided, part of which is passed through the finished caustic soda flake process to obtain 50% of the finished caustic soda, and part of which is configured as alkali liquor with a concentration of 61% through a pre-concentrator and enters a concentration system; the alkali liquor with a concentration of 61% enters a falling film tube for heating and concentration, and the alkali liquor concentration is controlled at 99%. The concentrated alkali liquor enters a finished product separator for separation, and after separation, it is distributed to several caustic soda flake machines through an alkali liquor distributor for caustic soda flake preparation; the finished caustic soda flakes prepared by the caustic soda flake machine are sent to a packaging station for packaging. The present invention provides a complete caustic soda process production line, greatly improves the preparation efficiency of caustic soda, and effectively reduces energy loss.

[0003] The above patent documents and prior art have the following technical problems when used:

[0004] Question 1: In the above patent documents and prior art, the temperature is not easy to accurately control during the preparation of calcium hydroxide or sodium hydroxide, which makes it difficult to effectively separate impurities, and the energy consumption is high, and heat energy cannot be recovered;

[0005] Question 2: In the above documents and prior art, it is impossible to carry out targeted treatment for impurities inside calcium hydroxide or sodium hydroxide, and it is difficult to deal with the problem of diverse impurity types;

[0006] Question three: The waste gas and waste heat generated in the process of preparing calcium hydroxide or sodium hydroxide in the above documents and existing technologies cannot be treated secondary, which has poor environmental protection and low energy utilization rate. Summary of the invention

[0007] Technical issues solved

[0008] In view of the deficiencies of the prior art, the present invention provides a low-cost and efficient purification method and process of calcium hydroxide based on temperature control, which solves the following problems:

[0009] 1. Traditional purification processes are difficult to cope with the problem of diverse impurities. Intelligent process control is adopted to collect and analyze data in real time through AI, dynamically adjust process parameters, optimize the purification process, and reduce human intervention;

[0010] 2. The temperature is not easy to control accurately in the traditional method, which makes it difficult to effectively separate impurities. The PID control algorithm can adjust the temperature in real time to solve the problem of reaction temperature fluctuation;

[0011] 3. Traditional processes are prone to produce untreated waste gas or waste materials, causing environmental pollution. This process uses green treatment equipment to conduct secondary treatment of waste gas and waste materials to achieve clean emissions.

[0012] Technical Solution

[0013] To achieve the above objectives, the present invention is implemented by the following technical scheme: a low-cost and efficient purification method and process of calcium hydroxide based on temperature control, the purification process is as follows:

[0014] Sp1: Raw material pretreatment, preliminary crushing and screening of the calcium hydroxide raw materials containing impurities to ensure uniform particles and remove most of the easily separable impurities;

[0015] Sp2: Refined temperature control and heating. The processed raw materials are sent into the reactor with temperature zone control for segmented heating. Each heating zone monitors the temperature in real time through sensors according to the volatilization point and decomposition temperature of different impurities, and the heating power is automatically adjusted using the PID control system.

[0016] Sp3: Multi-stage reaction and energy optimization. According to the different reaction temperatures of impurities, low temperature zone, medium temperature zone and high temperature zone are set in sequence for temperature control. Heat exchange is used to recover waste heat in each stage and use it in the preheating process of other stages.

[0017] Sp4: Intelligent process control, using AI and machine learning algorithms to intelligently monitor and adjust the entire reaction process, collect real-time data on temperature, reaction rate, and impurity concentration in the reactor. The AI ​​system adjusts the reaction parameters of each stage in real time based on the data fed back by the sensor, sets the heating power, temperature setting value, and reaction time. The AI ​​system continuously learns and optimizes the purification process through historical data modeling and process parameter optimization;

[0018] Sp5: Product cooling and waste treatment. The purified calcium hydroxide product is discharged from the reactor and enters the cooling device for cooling. The waste heat, waste gas and waste generated by the reaction are secondary treated by the green treatment device, and the waste heat is recycled again through the heat exchanger.

[0019] Preferably, in the refined temperature control and heating, temperature sensors are arranged in each heating zone of the reactor, and the relationship between temperature change and heating power is as follows:

[0020] P i =k i (T target,i -Tcurrent,i )

[0021] in:

[0022] P i is the heating power of the ith zone, which determines the energy output of the heater in this zone;

[0023] k i is the thermal conductivity coefficient of the ith region, indicating the heat transfer efficiency in this region;

[0024] T target,i is the target temperature of the i-th zone, reflecting the temperature that needs to be achieved in this stage;

[0025] T current,i is the current temperature of the ith region, which is the actual measured temperature.

[0026] Preferably, the refined temperature control and heating is based on a PID control algorithm to adjust the power of the heating element, and the PID control equation is used to accurately adjust the temperature, and the formula is as follows:

[0027]

[0028] in:

[0029] u(t), control signal, refers to the heating power adjustment, which is used to control the power of the heating element in each zone;

[0030] K p , is the proportional gain coefficient, which determines the temperature difference e(t) = T target,i -T current,i The degree of influence on heating power regulation;

[0031] K i , integral gain coefficient, reflects the impact of the accumulation of past temperature differences on the current heating power and is used to eliminate long-term steady-state errors;

[0032] K d , differential gain coefficient, reflects the influence of the rate of change of temperature difference on heating power, and is used to predict the trend of temperature difference and slow down over-response;

[0033] e(t), is the difference between the target temperature and the current temperature, which is the error that needs to be eliminated;

[0034] is the time integral of the error, indicating the cumulative effect of the error over time;

[0035] is the rate of change of the error, indicating the changing trend of the error over time.

[0036] Preferably, in the multi-stage reaction and energy optimization, the reaction process is divided into multiple temperature control stages according to the physicochemical properties of the impurities, and a different target temperature is set for each stage to separate specific impurities. The Arrhenius equation is used to describe the relationship between the reaction rate and temperature in each stage. The formula is as follows:

[0037]

[0038] in:

[0039] k(T) is the reaction rate constant, which indicates the speed of the reaction at temperature T and is used to describe the chemical reaction rate at different temperatures;

[0040] A is the frequency factor, which represents the frequency of molecular collisions and the probability of effective collisions, and is related to the nature of the reactants;

[0041] E a is the activation energy, which represents the minimum energy required for a reaction to occur. The higher the activation energy, the slower the reaction.

[0042] R is the gas constant, with a value of 8.314 J / mol, used to relate temperature to energy;

[0043] T is the absolute temperature, measured in Kelvin, which affects the kinetic energy of molecules and the probability of collision.

[0044] Preferably, in the multi-stage reaction and energy optimization, heat energy is recovered through a heat exchanger in each reaction stage, and the efficiency of energy recovery is evaluated using the Carnot efficiency formula, which is as follows:

[0045]

[0046] Carnot efficiency, which represents the maximum possible efficiency of extracting energy from a high-temperature heat source and converting it into useful work;

[0047] The absolute temperature of the low-temperature heat source, in Calvins. The higher the temperature, the lower the efficiency.

[0048] The absolute temperature of a high-temperature heat source, measured in Calvins. The higher the temperature, the higher the efficiency.

[0049] Preferably, in the intelligent process control, IoT devices are arranged throughout the purification process to monitor temperature, pressure, reaction rate and impurity concentration. The AI ​​system analyzes vertical data through a machine learning algorithm and optimizes the process by continuously updating and optimizing reaction conditions. The optimization formula is as follows:

[0050] max T，P，t E(T,P,t)

[0051] in:

[0052] E(T, P, t) is the purification efficiency function, which represents the efficiency of the purification process at a specific temperature T, heating power P, and reaction time t;

[0053] T is temperature, the reaction temperature at each stage in the process;

[0054] P is the heating power, which determines the input of thermal energy into the reactor;

[0055] t is the reaction time, which refers to the duration of the reaction at each stage.

[0056] Preferably, in the raw material pretreatment, when the impurity-containing calcium hydroxide raw material is crushed, the crushing particle size is controlled at 100-200 μm, iron filings and sediment impurities are removed by gravity sorting or magnetic suspension method, and a bag dust collector is used to treat dust emissions during the crushing process.

[0057] Preferably, in the refined temperature control and heating, a high-precision thermocouple temperature sensor is arranged in each heating zone to monitor temperature changes in real time. The temperature signal is transmitted to the PID controller through the control system, and the heating power is adjusted by the PID control algorithm to ensure that the temperature is always maintained in the optimal range.

[0058] Preferably, the multi-stage reaction and energy optimization further include the following:

[0059] The temperature of the low temperature zone is set at 100-200℃, mainly removing moisture, volatile impurities and low melting point organic matter;

[0060] The temperature in the medium temperature zone is set at 300-500°C to decompose inorganic impurities with medium melting points. At this time, the reaction rate is high, and the reaction time is optimized by temperature gradient control;

[0061] The temperature in the high temperature zone is set at 600-900°C to remove high temperature resistant impurities such as metal oxides to achieve high purity purification requirements of calcium hydroxide.

[0062] Preferably, the calcium hydroxide after purification in the product cooling and waste treatment enters the cooling system through a transmission device, and countercurrent cooling or air cooling technology is adopted to quickly cool the product. The waste heat is recovered again through a heat exchanger, part of which is used for preheating in the previous stage, and the rest can be used for heating or power generation in other plant areas. The waste gas generated during the reaction is treated by green environmental protection equipment and discharged after purification through a washing tower or a filtering device.

[0063] Beneficial Effects

[0064] The invention provides a low-cost and efficient calcium hydroxide purification method and process based on temperature control.

[0065] It has the following beneficial effects:

[0066] 1. The present invention adopts refined temperature control and zoned heating. Each heating zone monitors the temperature in real time according to the volatilization point and decomposition temperature of different impurities to ensure that the temperature in each stage accurately reaches the set value. The PID control algorithm is used to adjust the heating power to avoid overheating or underheating to ensure the purity of calcium hydroxide. The energy recovery system recovers the waste heat generated in the reaction process through a heat exchanger and uses it to preheat the raw materials in other stages, effectively reducing energy consumption.

[0067] 2. The present invention sets low-temperature zones, medium-temperature zones and high-temperature zones in the process, and heats the impurities in stages according to their physical and chemical properties. Through intelligent process control, combined with AI and machine learning technology, process parameters such as temperature, heating power and reaction time are adjusted in real time, and the purification process is dynamically optimized to ensure that the purification process is automated and intelligent. AI models historical data, continuously optimizes and learns, and improves purification effects and reaction rates.

[0068] 3. The process of the present invention adopts an environmentally friendly design, including waste heat, waste gas and waste material treatment devices. The waste heat generated during the reaction is recovered through a heat exchanger and reused in other process links to reduce energy consumption. At the same time, the waste gas is treated by a washing tower and a filtering device to ensure that the emission meets environmental protection standards. Waste materials such as metal impurities can be recovered through secondary utilization to reduce environmental pollution and waste of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 is a process flow chart of the present invention;

[0070] Figure 2 is a temperature variation curve of the present invention over time;

[0071] Figure 3 A curve showing a control signal generated by the PID controller of the present invention and time variation;

[0072] Figure 4 It is the curve of reaction rate changing with time of the present invention. DETAILED DESCRIPTION

[0073] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Specific embodiment one:

[0075] like Figure 1-4 As shown, a low-cost and efficient purification method and process of calcium hydroxide based on temperature control, the purification process is as follows:

[0076] Sp1: Raw material pretreatment, preliminary crushing and screening of the calcium hydroxide raw materials containing impurities to ensure uniform particles and remove most of the easily separable impurities;

[0077] Sp2: Refined temperature control and heating. The processed raw materials are sent to the reactor with temperature zone control for segmented heating. Each heating zone monitors the temperature in real time through sensors according to the volatilization point and decomposition temperature of different impurities. The heating power is automatically adjusted using the PID control system. In the refined temperature control and heating, temperature sensors are arranged in each heating zone of the reactor. The relationship between temperature change and heating power is as follows:

[0078] P i =k i (T target,i -T current,i )

[0079] in:

[0080] P i is the heating power of the ith zone, which determines the energy output of the heater in this zone;

[0081] k i is the thermal conductivity coefficient of the ith region, indicating the heat transfer efficiency in this region;

[0082] T target,i is the target temperature of the ith zone, reflecting the temperature that needs to be achieved in this stage.

[0083] T current,i is the current temperature of the ith region, which is the actual measured temperature.

[0084] In refined temperature control and heating, the power of the heating element is adjusted based on the PID control algorithm. The PID control equation is used to accurately adjust the temperature. The formula is as follows:

[0085]

[0086] in:

[0087] u(t), control signal, refers to the heating power adjustment used to control the power of the heating element in each zone;

[0088] K p , is the proportional gain coefficient, which determines the temperature difference e(t) = T target,i -T current,i The degree of influence on heating power regulation;

[0089] K i, integral gain coefficient, reflects the impact of the accumulation of past temperature differences on the current heating power and is used to eliminate long-term steady-state errors;

[0090] K d , differential gain coefficient, reflects the influence of the rate of change of temperature difference on heating power, and is used to predict the trend of temperature difference and slow down over-response;

[0091] e(t), is the difference between the target temperature and the current temperature, which is the error that needs to be eliminated;

[0092] is the time integral of the error, indicating the cumulative effect of the error over time;

[0093] is the rate of change of the error, indicating the trend of the error over time;

[0094] Sp3: Multi-stage reaction and energy optimization. According to the different reaction temperatures of impurities, low-temperature zones, medium-temperature zones and high-temperature zones are set in sequence for temperature control. Heat exchange is used to recover waste heat in each stage and use it in the preheating process of other stages. Low-temperature zones, medium-temperature zones and high-temperature zones are set in the process. According to the physical and chemical properties of impurities, heating treatment is carried out in stages. Through intelligent process control, combined with AI and machine learning technology, process parameters such as temperature, heating power and reaction time are adjusted in real time, and the purification process is dynamically optimized to ensure automation and intelligence of the purification process. AI continuously optimizes and learns through historical data modeling to improve the purification effect and reaction rate. In multi-stage reaction and energy optimization, according to the physical and chemical properties of impurities, the reaction process is divided into multiple temperature control stages. Different target temperatures are set for each stage to separate specific impurities. The Arrhenius equation is used to describe the relationship between the reaction rate and temperature in each stage. The formula is as follows:

[0095]

[0096] in:

[0097] k(T) is the reaction rate constant, which indicates the speed of the reaction at temperature T and is used to describe the chemical reaction rate at different temperatures;

[0098] A is the frequency factor, which represents the frequency of molecular collisions and the probability of effective collisions, and is related to the nature of the reactants;

[0099] E a is the activation energy, which represents the minimum energy required for a reaction to occur. The higher the activation energy, the slower the reaction.

[0100] R is the gas constant, with a value of 8.314 J / mol, used to relate temperature to energy;

[0101] T is the absolute temperature, measured in Kelvin, which affects the kinetic energy of molecules and the probability of collision.

[0102] Preferably, in multi-stage reaction and energy optimization, heat energy is recovered through a heat exchanger in each reaction stage, and the efficiency of energy recovery is evaluated using the Carnot efficiency formula, which is as follows:

[0103]

[0104] Carnot efficiency, which represents the maximum possible efficiency of extracting energy from a high-temperature heat source and converting it into useful work;

[0105] The absolute temperature of the low-temperature heat source, in Calvins. The higher the temperature, the lower the efficiency.

[0106] The absolute temperature of the high-temperature heat source, in Calvins. The higher the temperature, the higher the efficiency.

[0107] Sp4: Intelligent process control, using AI and machine learning algorithms to intelligently monitor and adjust the entire reaction process, collect temperature, reaction rate, and impurity concentration data in the reactor in real time, and adjust the reaction parameters of each stage in real time according to the data fed back by the sensor, set the heating power, temperature setting value, and reaction time. The AI ​​system continuously learns and optimizes the purification process, and through historical data modeling and process parameter optimization, in intelligent process control, IoT devices are arranged throughout the purification process to monitor temperature, pressure, reaction rate, and impurity concentration. The AI ​​system analyzes vertical data through machine learning algorithms, and optimizes the reaction conditions by continuously updating and optimizing the process. The optimization formula is as follows:

[0108] mαx T,P,t E(T,P,t)

[0109] in:

[0110] E(T, P, t) is the purification efficiency function, which represents the efficiency of the purification process at a specific temperature T, heating power P, and reaction time t;

[0111] T is temperature, the reaction temperature at each stage in the process;

[0112] P is the heating power, which determines the input of thermal energy into the reactor;

[0113] t is the reaction time, which refers to the duration of the reaction at each stage;

[0114] Sp5: Product cooling and waste treatment. The purified calcium hydroxide product is discharged from the reactor and enters the cooling device for cooling. The waste heat, waste gas and waste generated by the reaction are secondary treated by the green treatment device, and the waste heat is recycled again through the heat exchanger.

[0115] In actual use, in order to improve the accuracy of the entire process, the raw material pretreatment is set up, and the crushing particle size of the calcium hydroxide raw material containing impurities is controlled at 100-200μm. A vibration screening device is used to remove oversized or undersized particles to ensure uniform raw material particles and provide a uniform reaction basis for subsequent heating and reaction. Iron filings and mud impurities are removed by gravity sorting or magnetic suspension. A bag dust collector is used to treat dust emissions during the crushing process to reduce dust emissions during the crushing process, improve the working environment and reduce raw material losses.

[0116] In refined temperature control and heating, the reactor is divided into multiple independent heating zones, and each heating zone is set with a temperature control target. Different heating zone temperatures are designed according to the physical and chemical properties of the impurities, such as volatilization point, melting point, decomposition temperature, etc. The low temperature zone is used to remove low melting point and volatile impurities, such as moisture and light organic matter. The medium temperature zone is used to decompose impurities with higher melting points, such as sulfides and fluorides. The high temperature zone is used to completely decompose impurities that are difficult to volatilize, such as metal oxides, to ensure that the purity of calcium hydroxide is improved. A high-precision thermocouple temperature sensor is arranged in each heating zone to monitor temperature changes in real time. The temperature signal is transmitted to the PID controller through the control system, and the heating power is adjusted by the PID control algorithm to ensure that the temperature is always kept in the optimal range. The multi-stage reaction and energy optimization further include the following:

[0117] The low temperature zone is set at 100-200℃, mainly removing moisture, volatile impurities and low melting point organic matter. This stage uses lower energy consumption while ensuring that raw material decomposition is avoided;

[0118] The temperature in the medium temperature zone is set at 300-500℃ to decompose inorganic impurities with medium melting points. At this time, the reaction rate is high, and the reaction time is optimized by temperature gradient control, such as sulfides and fluorides. At this time, the reaction rate is high, and the reaction time is optimized by temperature gradient control;

[0119] The temperature of the high temperature zone is set at 600-900℃, which is used to remove high temperature resistant impurities such as metal oxides to achieve the high purity purification requirements of calcium hydroxide;

[0120] Refined temperature control and zoned heating are adopted. Each heating zone monitors the temperature in real time according to the volatilization point and decomposition temperature of different impurities to ensure that the temperature in each stage accurately reaches the set value. The PID control algorithm is used to adjust the heating power to avoid overheating or underheating and ensure the purity of calcium hydroxide. The energy recovery system recovers the waste heat generated in the reaction process through the heat exchanger and uses it to preheat the raw materials in other stages, effectively reducing energy consumption. Heat exchangers are installed in each stage to effectively recover waste heat, and the recovered heat energy is used to preheat the raw materials in the next stage to reduce overall energy consumption. Through the energy management system, the energy consumption of each reaction stage is monitored and adjusted in real time to ensure that the energy input and heat recovery process are efficient and waste-free. Environmentally friendly design is adopted, including waste heat, waste gas and waste material treatment devices. The waste heat generated in the reaction process is recovered through the heat exchanger and reused in other process links to reduce energy consumption. At the same time, the waste gas is treated by a scrubber and a filter to ensure that the emission meets environmental standards. Waste materials such as metal impurities can be recycled through secondary use to reduce environmental pollution and resource waste.

[0121] After the purification of calcium hydroxide in product cooling and waste treatment is completed, it enters the cooling system through a transmission device. Countercurrent cooling or air cooling technology is used to quickly cool the product. Air or water can be used as the cooling medium. Air cooling is achieved through fans, while water cooling is achieved through circulating water cooling towers. Waste heat is recovered again through a heat exchanger, part of which is used for preheating in the previous stage, and the rest can be used for heating or power generation in other plant areas. The exhaust gas generated during the reaction is treated by green environmental protection equipment and discharged after purification through a washing tower or filtering device. Specific embodiment 2:

[0123] like Figure 1-4 As shown, according to the content of the specific embodiment 1, the following contents are further disclosed:

[0124] The formula contents of each process stage in the specific embodiment 1 are subjected to feasible experimental processing, and the experimental contents and data contents are as follows:

[0125] like Figure 2 As shown in the figure, it is a curve of temperature change over time. This curve shows the change of temperature in the system over time. Due to the use of PID control algorithm, the temperature will be gradually adjusted to the target temperature in different temperature zones.

[0126] Initial stage: The temperature starts to rise from the initial temperature of 25°C, and the PID controller adjusts the heating power according to the difference between the target temperatures to make the temperature rise slowly;

[0127] Zoned heating: During the whole process, the system is divided into three temperature zones: low temperature zone: 150℃, medium temperature zone: 400℃, high temperature zone: 800℃. When the temperature reaches the target of the low temperature zone, the system automatically adjusts the heating power and enters the next temperature zone, and finally reaches the target temperature of 800℃ in the high temperature zone.

[0128] PID control effect: The PID controller adjusts the speed and stability of temperature rise through proportion, integration and differentiation to avoid overshoot or fluctuation, so that the temperature approaches the target temperature steadily;

[0129] Curve characteristics: The temperature rise in each stage is smooth and gradually approaches the target temperature. When the system switches to the next temperature zone, such as from the low temperature zone to the medium temperature zone, the temperature will continue to rise to the new target value;

[0130] like Figure 3 As shown, it is a curve of the control signal generated by the PID controller versus time, and the curve represents the control signal generated by the PID controller, that is, the adjustment amount of the heating power, versus time;

[0131] Initial stage: At the beginning, due to the large difference between the current temperature and the target temperature, the control signal will be relatively large to provide sufficient heating power;

[0132] Error reduction: As the system gradually approaches the target temperature, the error gradually decreases, the PID controller reduces the heating power, and the control signal tends to be stable;

[0133] Proportional term: directly adjust the control signal according to the temperature error. When the temperature difference is large, the control signal is large; when the temperature difference is small, the control signal gradually decreases.

[0134] Integral term: used to eliminate steady-state errors and increase control signals when temperature differences accumulate over a long period of time;

[0135] Differential term: By predicting the changing trend of the error, the system is prevented from over-adjusting, and the control signal gradually becomes flat when the temperature difference decreases;

[0136] Curve characteristics: The control signal is large in the initial stage of each temperature zone. As the temperature gradually approaches the target value, the control signal becomes smaller. If there is a large temperature fluctuation, the control signal may oscillate briefly, but eventually stabilize.

[0137] like Figure 4 As shown, it is a curve of reaction rate changing with time. This curve shows the reaction rate changing with time calculated according to the Arrhenius equation. The reaction rate is exponentially related to temperature. Therefore, as the temperature increases, the reaction rate will also increase.

[0138] Low temperature zone: In the low temperature zone, the reaction rate is slow due to the low temperature;

[0139] Medium temperature zone and high temperature zone: As the temperature enters the medium temperature zone and high temperature zone, the reaction rate increases rapidly, especially in the high temperature zone. Due to the high temperature and increased reaction rate, the decomposition and purification speed of impurities are significantly accelerated;

[0140] Effect of activation energy: The higher the activation energy, the slower the reaction rate, and the temperature needs to be high enough to effectively speed up the reaction rate;

[0141] Curve characteristics: The reaction rate curve is roughly consistent with the temperature curve. As the temperature rises, the reaction rate increases exponentially. In the high temperature zone, the reaction rate reaches the highest and the purification process is most active.

[0142] Based on the above:

[0143] Temperature control process: Through PID control, the temperature can gradually approach the target temperature of different temperature zones. Each zone has a reasonable heating time and temperature control accuracy. The control signal curve shows the adjustment process of the heating power. The system can adjust the power of the heater in real time according to the temperature difference to prevent temperature overshoot or fluctuation. The reaction rate increases significantly in areas with higher temperatures, indicating that the purification effect in high temperature areas is most significant, which is in line with the temperature dependence of the chemical reaction rate, realizing an efficient calcium hydroxide purification process, and further improving the efficiency of the entire process through energy recovery and reaction rate optimization. Specific embodiment three:

[0145] like Figure 1-4 As shown, according to the content in specific embodiment one, an experiment of preparing calcium hydroxide was carried out, and the experimental data content is as follows:

[0146] Experiment 1: Standard purification process, traditional temperature control and energy optimization

[0147] step:

[0148] Raw material pretreatment: The raw material is calcium hydroxide containing 20% ​​impurities, the crushed particle size is 150μm, the impurity types are metal oxides, moisture and organic matter, etc., and the removal method is gravity separation and bag dust collector;

[0149] Temperature control and segmented heating:

[0150] Low temperature zone temperature: 150°C, maintained for 30 minutes, used to remove moisture and low melting point organic matter;

[0151] Medium temperature zone temperature: 400°C, maintained for 45 minutes, used to decompose inorganic impurities;

[0152] High temperature zone temperature: 800°C, maintained for 60 minutes, separation of metal oxides;

[0153] Energy consumption: The temperature control in each stage is a fixed value, based on the traditional temperature control algorithm;

[0154] Heat recovery and optimization: waste heat is recovered through heat exchangers, and 40% of the heat energy is used in the preheating stage;

[0155] Intelligent process control (without AI): process monitoring and regulation based on manual adjustment and PID control, mainly monitoring reaction rate and impurity concentration, and manually adjusting reaction time and heating power;

[0156] Product cooling: countercurrent air cooling system, product temperature is reduced to 30°C, waste heat recovery rate is 30%;

[0157] Data results:

[0158] The impurity removal rate is 95%; the final calcium hydroxide purity is 98%; the energy consumption is 4000kWh; and the overall process time is 3.5 hours.

[0159] Experiment 2: Intelligent temperature control purification process, AI assistance and precise temperature control

[0160] step:

[0161] Raw material pretreatment: The raw material is calcium hydroxide containing 15% impurities, the crushed particle size is 100μm, the impurity types are metal oxides, moisture and organic matter, etc. The removal method is magnetic suspension separation of iron filings and gravity separation, and bag dust collector removes dust;

[0162] Refined temperature control and heating:

[0163] Low temperature zone temperature: 175°C, maintained for 25 minutes, with AI adjusting the optimized time to remove moisture and low-melting-point organic matter;

[0164] Medium temperature zone temperature: 450°C, maintained for 35 minutes, the AI ​​system adjusts the reaction rate based on real-time data.

[0165] High temperature zone temperature: 850°C, maintained for 50 minutes, AI continuously monitors the temperature to ensure separation of metal oxides;

[0166] Energy consumption: Based on AI adjustment and PID algorithm control, the heating power can be precisely adjusted;

[0167] Multi-stage heat recovery and optimization: Through AI-optimized heat exchangers, waste heat recovery reaches 60% for preheating and plant heating;

[0168] Intelligent process control: AI monitors the temperature, impurity concentration, and reaction rate in the reactor in real time, automatically optimizes heating power, temperature setting value, and reaction time, and combines PID control with AI algorithms to continuously learn and optimize the purification process;

[0169] Product cooling: counter-current air cooling, cooling to 25°C, waste heat recovery rate of 50%, used for power generation in the plant;

[0170] Data results: impurity removal rate is 99%; final calcium hydroxide purity is 99.5%; energy consumption is 3200kWh; overall process time is 2.75 hours.

[0171] According to the contents of Experiment 1 and Experiment 2, data comparison is carried out, and the comparison contents are shown in Table 1 and Table 2 below:

[0172] index Standard purification process Intelligent temperature control purification process Impurity removal rate 95％ 99％ Calcium hydroxide purity 98％ 99.5％ Total energy consumption 4000kWh 3200kWh Heat recovery rate 40％ 60％ Process time 3.5 hours 2.75 hours

[0173] Table 1

[0174]

[0175] Table 2

[0176] According to Tables 1 and 2 above, the intelligent process has shown significant advantages in purification efficiency, energy consumption optimization, heat recovery and process time. AI-assisted control makes the reaction process more intelligent and efficient, reduces human intervention, and reduces production costs. Refined temperature control and energy recovery technology improve resource utilization, reduce environmental burden, and improve output quality.

[0177] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprising a reference structure" do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0178] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low-cost and efficient calcium hydroxide purification process based on temperature control, characterized in that: The purification process is as follows: Sp1: Raw material pretreatment, preliminary crushing and screening of the calcium hydroxide raw materials containing impurities to ensure uniform particles and remove most of the easily separable impurities; Sp2: Refined temperature control and heating. The processed raw materials are sent into the reactor with temperature zone control for segmented heating. Each heating zone monitors the temperature in real time through sensors according to the volatilization point and decomposition temperature of different impurities, and the heating power is automatically adjusted using the PID control system. Sp3: Multi-stage reaction and energy optimization. According to the different reaction temperatures of impurities, low temperature zone, medium temperature zone and high temperature zone are set in sequence for temperature control. Heat exchange is used to recover waste heat in each stage and use it in the preheating process of other stages. Sp4: Intelligent process control, using AI and machine learning algorithms to intelligently monitor and adjust the entire reaction process, collect real-time data on temperature, reaction rate, and impurity concentration in the reactor. The AI ​​system adjusts the reaction parameters of each stage in real time based on the data fed back by the sensor, sets the heating power, temperature setting value, and reaction time. The AI ​​system continuously learns and optimizes the purification process through historical data modeling and process parameter optimization; Sp5: Product cooling and waste treatment. The purified calcium hydroxide product is discharged from the reactor and enters the cooling device for cooling. The waste heat, waste gas and waste generated by the reaction are secondary treated by the green treatment device, and the waste heat is recycled again through the heat exchanger.

2. A low-cost calcium hydroxide efficient purification process based on temperature control according to claim 1, characterized in that: In the refined temperature control and heating, temperature sensors are arranged in each heating zone of the reactor. The relationship between temperature change and heating power is as follows: P i =k i (T target,i -T current,i ) in: P i is the heating power of the ith zone, which determines the energy output of the heater in this zone; k i is the thermal conductivity coefficient of the ith region, indicating the heat transfer efficiency in this region; T target,i is the target temperature of the i-th zone, reflecting the temperature that needs to be achieved in this stage; T current,i is the current temperature of the ith region, which is the actual measured temperature.

3. A low-cost calcium hydroxide efficient purification process based on temperature control according to claim 1, characterized in that: The refined temperature control and heating is based on the PID control algorithm to adjust the power of the heating element. The PID control equation is used to accurately adjust the temperature. The formula is as follows: in: u(t), control signal, refers to the heating power adjustment, which is used to control the power of the heating element in each zone; K p , is the proportional gain coefficient, which determines the temperature difference e(t) = T target,i -T current,i The degree of influence on heating power regulation; K i , integral gain coefficient, reflects the impact of the accumulation of past temperature differences on the current heating power and is used to eliminate long-term steady-state errors; K d , differential gain coefficient, reflects the influence of the rate of change of temperature difference on heating power, and is used to predict the trend of temperature difference and slow down over-response; e(t), is the difference between the target temperature and the current temperature, which is the error that needs to be eliminated; is the time integral of the error, indicating the cumulative effect of the error over time; is the rate of change of the error, indicating the changing trend of the error over time.

4. A low-cost calcium hydroxide efficient purification process based on temperature control according to claim 1, characterized in that: In the multi-stage reaction and energy optimization, the reaction process is divided into multiple temperature control stages according to the physicochemical properties of the impurities. Different target temperatures are set for each stage to separate specific impurities. The Arrhenius equation is used to describe the relationship between the reaction rate and temperature in each stage. The formula is as follows: in: k(T) is the reaction rate constant, which indicates the speed of the reaction at temperature T and is used to describe the chemical reaction rate at different temperatures; A is the frequency factor, which represents the frequency of molecular collisions and the probability of effective collisions, and is related to the nature of the reactants; E a is the activation energy, which represents the minimum energy required for a reaction to occur. The higher the activation energy, the slower the reaction. R is the gas constant, with a value of 8.314 J / mol, used to relate temperature to energy; T is the absolute temperature in Kelvin, which affects the kinetic energy of molecules and the probability of collision.

5. A low-cost calcium hydroxide efficient purification process based on temperature control according to claim 1, characterized in that: In the multi-stage reaction and energy optimization, heat energy is recovered through a heat exchanger in each reaction stage, and the efficiency of energy recovery is evaluated using the Carnot efficiency formula, which is as follows: Carnot efficiency, which represents the maximum possible efficiency of extracting energy from a high-temperature heat source and converting it into useful work; The absolute temperature of the low-temperature heat source, in Calvins. The higher the temperature, the lower the efficiency. The absolute temperature of a high-temperature heat source, measured in Calvins. The higher the temperature, the higher the efficiency.

6. A low-cost calcium hydroxide efficient purification process based on temperature control according to claim 1, characterized in that: In the intelligent process control, IoT devices are arranged throughout the purification process to monitor temperature, pressure, reaction rate and impurity concentration. The AI ​​system analyzes vertical data through machine learning algorithms and optimizes the process by continuously updating and optimizing reaction conditions. The optimization formula is as follows: max T,P,t E(T,P,t) in: E(T, P, t) is the purification efficiency function, which represents the efficiency of the purification process at a specific temperature T, heating power P, and reaction time t; T is temperature, the reaction temperature at each stage in the process; P is the heating power, which determines the input of thermal energy into the reactor; t is the reaction time, which refers to the duration of the reaction at each stage.

7. A method for a low-cost calcium hydroxide efficient purification process based on temperature regulation according to any of claims 1-6, characterized in that: In the raw material pretreatment, the particle size of the calcium hydroxide raw material containing impurities is controlled to be 100-200 μm when the raw material is crushed, iron filings and sand impurities are removed by gravity sorting or magnetic suspension, and a bag dust collector is used to treat dust emissions during the crushing process.

8. A method according to any of claims 1 to 6 for a low-cost, temperature-controlled, efficient purification process for calcium hydroxide, characterized in that: In the refined temperature control and heating, a high-precision thermocouple temperature sensor is arranged in each heating zone to monitor temperature changes in real time. The temperature signal is transmitted to the PID controller through the control system, and the heating power is adjusted by the PID control algorithm to ensure that the temperature is always maintained in the optimal range.

9. A method for a low-cost calcium hydroxide efficient purification process based on temperature regulation according to any of claims 1-6, characterized in that: The multi-stage reaction and energy optimization further include the following: The temperature of the low temperature zone is set at 100-200℃, mainly removing moisture, volatile impurities and low melting point organic matter; The temperature in the medium temperature zone is set at 300-500°C to decompose inorganic impurities with medium melting points. At this time, the reaction rate is high, and the reaction time is optimized by temperature gradient control; The temperature in the high temperature zone is set at 600-900°C to remove high temperature resistant impurities such as metal oxides to achieve high purity purification requirements of calcium hydroxide.

10. A method for a low-cost calcium hydroxide efficient purification process based on temperature control according to any of claims 1-6, characterized in that: After the calcium hydroxide is purified in the product cooling and waste treatment, it enters the cooling system through a transmission device, and the countercurrent cooling or air cooling technology is adopted to quickly cool the product. The waste heat is recovered again through a heat exchanger, part of which is used for preheating in the previous stage, and the rest can be used for heating or power generation in other plant areas. The waste gas generated during the reaction is treated by green environmental protection equipment and discharged after purification through a washing tower or a filtering device.

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