Process and system for high purity lime production

Abstract

The present application relates to the technical field of lime manufacturing, and provides a process and system for high-purity lime manufacturing. The process comprises the steps of raw material pretreatment, plasma surface pretreatment, multi-stage atmosphere calcination, sound wave enhanced mass transfer, comprehensive utilization of heat energy and intelligent control, rapid cooling, flue gas treatment and finished product packaging. The system comprises a raw material pretreatment unit, a plasma surface pretreatment unit, a multi-stage gradient atmosphere calcination kiln, a sound wave enhanced mass transfer system, a comprehensive utilization of heat energy and intelligent control system, a carbon dioxide capture and resource utilization unit and a finished product cooling and packaging unit. Through raw material deep purification, surface activation treatment, gradient calcination and atmosphere precise control, sound wave mass transfer enhancement, intelligent optimization and regulation, rapid cooling and flue gas purification and resource recovery, the purity and reactivity of calcium oxide products are synergistically improved, the production energy consumption and pollutant emissions are significantly reduced, and efficient, clean and resourceful production of high-purity lime is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lime manufacturing, in particular to a process and system for high-purity lime manufacturing. BACKGROUND

[0002] Lime, as a basic industrial raw material, has wide application value in metallurgy, chemical industry, building materials, environmental protection and other fields. High-purity lime plays a key role in steel refining, chemical production, waste gas treatment, water treatment and other processes, and the purity and activity of its products directly affect the quality and economic benefits of downstream processes. The preparation of lime usually takes natural limestone as raw material, and calcium carbonate is decomposed to form calcium oxide by calcination reaction under high temperature conditions. However, in actual production, factors such as raw material properties, calcination conditions and cooling methods can significantly affect the quality and preparation cost of the final lime product.

[0003] The existing lime production technology mainly uses vertical kiln or rotary kiln and other thermal equipment for calcination. Although this traditional process has been widely used, it still has limitations in many aspects. In the raw material link, the purity and impurity content of limestone from different sources differ greatly, making it difficult to ensure the homogeneity and high purity of the raw material. In the calcination link, the traditional kiln has local areas of insufficient or excessive calcination, thereby reducing the purity and activity of the product. In terms of combustion and atmosphere control, the existing technology generally lacks precise control means, resulting in high energy consumption and high-emission waste pollution. In the product cooling link, the commonly used air cooling or water cooling methods not only have limited cooling efficiency, but also are difficult to effectively avoid the phenomenon of moisture absorption and carbonization during the cooling process, thereby affecting the storage stability and transportation performance of the product. In addition, the existing technology still lacks a mature and industrialized integrated solution to reduce energy consumption and pollutant emissions.

[0004] Therefore, it is urgent to develop a process and system for high-purity lime manufacturing to reduce energy consumption and pollutant emissions while ensuring high purity and high activity. SUMMARY

[0005] To solve the problems in the background art, the present application provides a process for high-purity lime manufacturing, comprising the following steps:

[0006] S1, raw material pretreatment; limestone raw material is uniformly fed through a vibrating feeder, particles with a particle size of 5-20 mm are screened out, and ferromagnetic impurities are removed by a magnetic separation device to realize particle size homogenization and impurity purification of the raw material;

[0007] S2, plasma surface pretreatment; the treated limestone particles are subjected to surface treatment by low-temperature atmospheric pressure plasma to remove surface organic contaminants and oxide layers;

[0008] S3, segment atmosphere calcination; limestone particles are sequentially passed through a preheating section, a decarburization section, a primary calcination section, and a deep calcination section for gradient temperature calcination, the temperatures of the sections are controlled at 400-600℃, 600-900℃, 900-1100℃, and 1100-1250℃ respectively, the primary calcination section adopts a weak reducing atmosphere, and the deep calcination section adopts an oxidizing atmosphere;

[0009] S4, sound wave reinforced mass transfer; subsonic waves and ultrasonic waves are applied simultaneously during calcination to promote CO2 gas diffusion in the particles and surface reaction product stripping through mechanical vibration and cavitation effects of the sound waves;

[0010] S5, thermal energy comprehensive utilization and intelligent control; real-time collection of temperature, pressure, and gas composition process parameters during calcination is achieved through a distributed sensor network, a process parameter optimization model is established, and fuel supply and air supply parameter adjustment is realized; meanwhile, high-temperature waste heat generated during calcination is recycled and utilized;

[0011] S6, rapid cooling; nanofluid spraying and forced air cooling are combined to rapidly cool high-temperature calcium oxide;

[0012] S7, flue gas treatment; multi-stage cooling and purification treatment of calcination flue gas is performed to recover CO2 therein, achieve standard emission of flue gas, and realize resource utilization of CO2;

[0013] S8, finished product packaging; calcium oxide is indirectly cooled to room temperature under inert atmosphere protection, and dry nitrogen is filled for sealing and packaging.

[0014] In the preferred scheme, the step S1 comprises:

[0015] S11, vibration feeding pre-screening; continuous feeding is performed through an electromagnetic vibration feeder with a vibration frequency of 15-25 Hz, the feeding speed is controlled at 2-5 t / h, and preliminary screening is performed to remove fine powder with a particle size less than 3 mm to avoid material agglomeration and blockage;

[0016] S12, multi-stage particle size accurate screening; three-layer vibration screens are used for grading, the first layer of screen hole is 20 mm to screen out oversized particles, the second layer of screen hole is 5 mm to screen out small particles, and the third layer of screen hole is used to ensure that 5-20 mm particles pass through and are graded, oversized particles are returned after crushing, and undersized particles are used as filler;

[0017] S13, two-stage magnetic separation deep purification; first, weak magnetic impurities are removed through a low-intensity magnetic separator with a magnetic field strength of 800-1200 Gauss, and then strong magnetic impurities are removed through a high-intensity magnetic separator with a magnetic field strength of 8000-12000 Gauss, the magnetic separation speed is controlled at 0.5-1.0 m / s, and high-purity limestone raw materials are obtained.

[0018] In a preferred embodiment, the step S2 comprises:

[0019] S21, plasma field establishment; a dielectric barrier discharge device with a power of 1.5-2.0 kW and a working voltage of 3-5 kV is used to generate low-temperature atmospheric pressure plasma, the discharge frequency is 20-50 kHz, and a uniform plasma field is formed in the processing chamber;

[0020] S22, particle surface micro-modification; the limestone particles stay in the plasma field for 30-60 seconds to remove the surface organic contaminants and oxide layers; at the same time, plasma bombardment on the limestone surface generates point defects, line defects and lattice defects to form high-activity reaction sites.

[0021] In a preferred embodiment, the step S3 comprises:

[0022] S31, preheating by residual heat; in the 400-600℃ preheating section, the high-temperature flue gas at 1000-1200℃ from the kiln tail is used to indirectly preheat the material through a plate heat exchanger, and the material temperature is uniformly raised to 580-620℃, realizing thermal energy cascade utilization;

[0023] S32, oxygen-enriched decarburization pretreatment; in the 600-900℃ decarburization preheating section, oxygen-enriched gas with an oxygen content of 25%-30% is introduced, and the flow rate is controlled at 100-150 Nm 3 / h to promote the start of the calcium carbonate decomposition reaction;

[0024] S33, weak reduction primary calcination; in the 900-1100℃ primary calcination section, a weak reduction atmosphere with a CO concentration of 1%-3% is used to inhibit the further oxidation of Fe2O3 and Al2O3 impurities, obtain a preliminary calcium oxide product, and ensure the high-purity characteristics of the product;

[0025] S34, high-temperature oxidation atmosphere deep calcination; in the 1100-1250℃ deep calcination section, an oxidation atmosphere with an oxygen concentration of 18%-20% is used, and the residence time is controlled at 45-60 minutes to completely decompose the residual calcium carbonate and obtain a calcium oxide product.

[0026] In a preferred embodiment, the step S4 comprises:

[0027] S41, mass transfer promotion by infrasound waves; in the primary calcination and deep calcination stages, infrasound waves with a frequency of 35-45 Hz and a sound pressure level of 80-100 dB are applied, the sound wave generator uses electromagnetic excitation to make the sound waves penetrate to the inside of the reactant particles, and low-frequency mechanical vibration is used to promote the diffusion and mass transfer of CO2 gas in the particles, accelerating the removal of reaction gas;

[0028] S42, surface activation by ultrasonic waves; at the same time, ultrasonic waves with a frequency of 18-22 kHz and a sound power density of 2-5 W / cm 2The ultrasonic waves produce cavitation effect and microjet on the surface of the reaction material, which accelerates the stripping of the surface reaction product CaO.

[0029] In a preferred embodiment, the step S5 comprises:

[0030] S51, real-time data acquisition monitoring; through the temperature sensor, pressure sensor, gas component analyzer and flow sensor distributed in each section of the calcination kiln, the temperature 、 、 、 , pressure 、 、 、 , oxygen concentration , carbon dioxide concentration , fuel flow , air flow key parameters, wherein is the preheating section temperature (℃); is the decarburization section temperature (℃); is the primary calcination section temperature (℃); is the deep calcination section temperature (℃); is the preheating section pressure (Pa); is the decarburization section pressure (Pa); is the primary calcination section pressure (Pa); is the deep calcination section pressure (Pa); is the oxygen concentration (%); is the carbon dioxide concentration (%); is the fuel flow (Nm 3 / h); is the air flow (Nm 3 / h), and a real-time database is established;

[0031] S52, data preprocessing and feature extraction; the collected raw data is filtered and denoised, and Kalman filtering algorithm is used to eliminate measurement noise;

[0032] S53, machine learning model training and updating; a deep neural network algorithm is used to establish a process parameter optimization model, and principal component analysis method is used for feature selection;

[0033] S54, optimal parameter calculation and prediction; taking product purity , activity and energy consumption as the multi-objective optimization function, the objective function is established as:

[0034] ;

[0035] wherein, is the comprehensive evaluation function; , , is the weight coefficient adjusted according to the actual process requirements (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z) , , , the optimal fuel flow rate is calculated:

[0036] ;

[0037] wherein, is the optimal fuel flow rate (Nm 3 / h); is the neural network mapping function; is the preheating section measured temperature (℃); is the decarburization section measured temperature (℃); is the primary calcination section measured temperature (℃); is the deep calcination section measured temperature (℃); is the oxygen concentration (%); is the carbon dioxide concentration (%);

[0038] At the same time, the optimal air flow rate is calculated:

[0039] ;

[0040] wherein, is the optimal air flow rate (Nm 3 / h); is the neural network mapping function; , , , are the respective section pressures (Pa);

[0041] S55, dynamic parameter automatic regulation; according to the optimization calculation results, the fuel supply amount, the air supply amount and the residual heat distribution ratio are automatically adjusted by a PID control algorithm, and a fuel control output is obtained;

[0042] S56, residual heat comprehensive recovery and utilization; high-temperature flue gas is used to generate electricity through an organic Rankine (ORC) system circulating power generation device, and at the same time, low-temperature residual heat is used to prepare process hot water, so as to realize energy cascade utilization and comprehensive recovery.

[0043] In the preferred scheme, the step S6 comprises:

[0044] S61, nanofluid rapid cooling; Al2O3, H2O nanofluid is used as cooling medium, the concentration of nanoparticles is 1%-3%vol, the nanoparticles are prepared by ultrasonic dispersion technology and a stabilizer is added to maintain stability, the high-temperature calcium oxide at 1150-1250℃ is sprayed and cooled through a high-pressure nozzle at a pressure of 3-5MPa, the spraying time is 30-45 seconds, the material temperature is rapidly reduced to 600-700℃, the first stage rapid cooling is realized, and excessive sintering of the calcium oxide under high temperature conditions is avoided;

[0045] S62, circulating forced air cooling; the circulating cooling air system is started immediately after the nanofluid spraying cooling, the air speed is controlled to be 15-20m / s, the air temperature is controlled to be 30-50℃, the forced air cooling time is 90-120 seconds, the material temperature is further reduced to 150-200℃, the second stage cooling process is completed, and the microstructure and high activity characteristics of the calcium oxide particles are maintained;

[0046] S63, inert atmosphere protection cooling; through the combined cooling effect of the previous two steps, the rapid cooling is realized within a total cooling time of 2-3 minutes, and N2 or Ar inert gas is introduced for protection, the gas flow is controlled to be 50-80Nm 3 / h, and the calcium oxide is prevented from reacting with CO2 and H2O in the air.

[0047] In the preferred scheme, the step S7 comprises;

[0048] S71, flue gas cooling and purification pretreatment; the high-temperature flue gas generated in the calcination process at 1000-1200℃ is sequentially cooled to 800℃, 400℃ and 200-250℃ through a three-stage series heat exchanger; then the dust in the flue gas is removed through a cyclone dust collector and a bag dust collector, and then SO2 is removed through a desulfurization tower; finally, the temperature is cooled to 40-50℃;

[0049] S72, efficient CO2 separation and capture; 30wt% MEA ethanolamine solution is used to contact with the purified flue gas in a countercurrent manner in a packed absorption tower, the operation pressure of the absorption tower is 0.1-0.15MPa, the temperature is 40-60℃, the circulation amount of the MEA solution is 500-800L / h, the CO2-rich solution is regenerated at 120-130℃ through a desorption tower at a desorption pressure of 0.15-0.2MPa, and the efficient separation and recovery of CO2 are realized;

[0050] S73, CO2 high-value resource utilization; the captured CO2 is compressed to 5MPa by a compressor and then transported to the downstream, reacts with the prepared CaO in a stirring reaction kettle to prepare nanometer calcium carbonate, or is transported to a methanol synthesis device to synthesize methanol under the action of a Cu-Zn-Al catalyst, and CO2 emission reduction and resource utilization are realized.

[0051] In the preferred scheme, the step S8 comprises;

[0052] S81, full-closed inert atmosphere conveying; conveying the calcium oxide product with a temperature of 150-200 DEG C after quenching through a closed screw conveyor, and filling the conveying pipeline with N2 inert gas with a purity of ≥99.5 %;

[0053] S82, indirect cooling to normal temperature; continuing to cool the calcium oxide in conveying, so that the product temperature is reduced to within +5 DEG C of the ambient temperature;

[0054] S83, automatic quantitative sealing and packaging; accurately weighing and packaging the calcium oxide through an electronic scale, and filling the dry N2 gas after packaging, so that the oxygen content in the bag is <0.1 %.

[0055] The application also provides a high-purity lime manufacturing system, comprising:

[0056] A raw material pretreatment unit is arranged at the feeding end of the system, comprising a vibrating feeder, a three-layer vibrating screen separator and a double-stage magnetic separation device connected in series, to realize uniform feeding, accurate screening and deep iron removal and purification of the limestone raw material;

[0057] A plasma surface pretreatment unit is connected with the outlet of the raw material pretreatment unit through a closed conveying pipeline, comprising a dielectric barrier discharge plasma generator, a treatment chamber and a material conveying device, to perform surface activation treatment on the limestone particles, remove surface organic contaminants and oxide layers, and form high-activity reaction sites;

[0058] A multi-section gradient atmosphere calcination kiln is connected with the outlet of the plasma surface pretreatment unit through a feeding port, has a multi-section kiln body structure, and comprises a preheating section, a decarburization section, a primary calcination section and a deep calcination section arranged from top to bottom, to realize gradient temperature rising calcination and complete decomposition of the limestone, wherein the preheating section is indirectly preheated by high-temperature flue gas at the kiln tail, the decarburization section is supplied with oxygen-rich gas to promote preliminary decomposition of calcium carbonate, the primary calcination section adopts a weak reducing atmosphere to inhibit oxidation of impurities, and the deep calcination section adopts an oxidizing atmosphere to realize complete decomposition of calcium carbonate;

[0059] An acoustic wave reinforced mass transfer system is installed in the primary calcination section and the deep calcination section of the multi-section gradient atmosphere calcination kiln, and comprises a subsonic wave generator and an ultrasonic wave generator, to promote CO2 gas diffusion inside the particles through subsonic waves and accelerate surface reaction product stripping through the cavitation effect of ultrasonic waves;

[0060] The heat energy comprehensive utilization and intelligent control system is connected with the multi-section gradient atmosphere calcination kiln through signal cables and control pipelines, and comprises a distributed sensor network, a data processing unit, a machine learning optimization module, a control execution unit and a waste heat recovery device; the distributed sensor network collects temperature, pressure, gas composition and flow parameters of each section in real time and transmits them to the data processing unit; the machine learning optimization module establishes a process parameter optimization model to calculate optimal fuel supply and air flow; the control execution unit automatically adjusts relevant parameters according to the optimization results; and the waste heat recovery device generates electricity and prepares hot water by using high-temperature flue gas.

[0061] The rapid cooling unit is connected with the material outlet of the multi-section gradient atmosphere calcination kiln, and comprises a nanofluid spraying system and a forced air cooling system; the nanofluid spraying system sprays nanofluid to cool high-temperature calcium oxide; and the forced air cooling system performs second-stage cooling to realize rapid cooling and maintain product activity.

[0062] The flue gas treatment unit is connected with the flue gas outlet of the multi-section gradient atmosphere calcination kiln through a flue gas pipeline, and comprises a multi-stage heat exchanger, a dust removal and purification device, a CO2 absorption and separation device and a CO2 utilization device; the multi-stage heat exchanger cools high-temperature flue gas; the dust removal and purification device removes dust and SO2 in the flue gas; the CO2 absorption and separation device captures CO2 in the flue gas by using ethanolamine solution; and the CO2 utilization device uses the recovered CO2 to prepare nanometer calcium carbonate or synthesize methanol.

[0063] The finished product packaging unit is connected with the rapid cooling unit through a sealed pipeline, and comprises an inert atmosphere conveying system, an indirect cooling device and an automatic packaging equipment; the inert atmosphere conveying system conveys calcium oxide products in a sealed environment filled with inert gas; the indirect cooling device cools the products to room temperature; and the automatic packaging equipment quantitatively packages the calcium oxide and fills it with dry nitrogen gas for sealing.

[0064] The present application has the following beneficial effects:

[0065] Firstly, the present application realizes the uniformization of particle size and deep impurity removal of limestone raw materials through the vibration screening and double-stage magnetic separation in the raw material pretreatment stage, significantly improves the purity of raw materials, and provides high-quality material basis for subsequent high-temperature calcination. The plasma surface pretreatment utilizes low-temperature atmospheric pressure plasma to bombard the surface of particles, effectively removes organic pollutants and oxide layers, and introduces a large number of lattice defects on the surface to form high-activity reaction sites, thereby significantly enhancing the reaction activity and decomposition efficiency of limestone in the calcination process. The multi-stage atmosphere calcination realizes the gradient decomposition of calcium carbonate and impurity control through multi-stage temperature control and atmosphere regulation of preheating, decarburization, primary calcination and deep calcination, avoids the quality problems caused by excessive oxidation or reduction, and guarantees the high purity and uniformity of the final product. The sound wave reinforced mass transfer technology promotes the diffusion of CO2 inside the particles and the separation of surface reaction products through the synergistic effect of infrasound and ultrasonic waves, significantly accelerates the mass transfer rate, shortens the calcination time, and improves the product activity and consistency.

[0066] Secondly, the present application realizes the accurate matching of fuel and air volume and the efficient recovery of waste heat through real-time collection of key process parameters by a distributed sensor network and multi-objective optimization and dynamic control by means of a machine learning model, significantly reduces the comprehensive energy consumption, and improves the stability and energy utilization efficiency of system operation. In the rapid cooling stage, nanofluid spraying and inert atmosphere protection are combined to effectively inhibit the recarbonization and sintering of calcium oxide, maintain the high activity and microstructure integrity of the product. Through the integrated process of multi-stage cooling, dust removal, desulfurization and CO2 capture resources, the purification of calcination flue gas and the efficient recovery and resource utilization of CO2 are realized, which significantly reduces the pollutant emissions and improves the environmental performance. The finished product packaging is carried out under the protection of inert atmosphere, combined with indirect cooling and automatic sealing and nitrogen filling packaging, which effectively prevents product moisture absorption and quality deterioration, and ensures the high purity and high activity of the product in the storage and transportation process. The synergistic effect of multiple technologies in the whole process and system realizes the comprehensive improvement of high-purity lime products in quality, energy consumption, environmental protection and economy.

[0067] Thirdly, the present application integrates plasma surface pretreatment, sound wave reinforced mass transfer, multi-stage gradient atmosphere calcination and intelligent control, significantly improves the product quality, and the calcium oxide prepared by the present application has a purity of 98.92% and an activity of 385 mL; at the same time, the comprehensive energy consumption per unit product is reduced to 850 kgce / t, and the carbon dioxide recovery utilization rate is 15%, which effectively reduces the pollutant emissions; in addition, the production efficiency is significantly improved, and additional economic benefits are brought by waste heat power generation and resource utilization. BRIEF DESCRIPTION OF DRAWINGS

[0068] Figure 1 is a column graph comparing the purity of calcium oxide of Example 1 and Comparative Examples 1-3.

[0069] Figure 2 is a comparison bar chart of the activity degree of Example 1 and Comparative Examples 1-3.

[0070] Figure 3 is a comparison bar chart of the unit product comprehensive energy consumption of Example 1 and Comparative Examples 1-3.

[0071] Figure 4 is a comparison chart of the environmental protection emission index of Example 1 and Comparative Examples 1-3.

[0072] Figure 5 is a comparison chart of the production efficiency index of Example 1 and Comparative Examples 1-3.

[0073] Figure 6 is a comparison time series chart of the product quality stability of Example 1 and Comparative Examples 1-3.

[0074] Figure 7 is a process flow chart for high-purity lime manufacturing. DETAILED DESCRIPTION

[0075] The technical solutions in the present application will be described clearly and completely below in combination with the drawings in the present application, and additionally, the forms of each structure described in the following embodiments are only examples, and the present application is not limited to each structure described in the following embodiments, and all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0076] The present application provides a process for high-purity lime manufacturing, referring to Figure 7 , the detailed process is as follows:

[0077] Step S1 raw material pretreatment; first perform step S11 vibration feeding pre-screening, using an electromagnetic vibration feeder to continuously and stably feed. The electromagnetic vibration feeder drives the armature to vibrate through the alternating magnetic field generated by the electromagnetic coil, and then drives the trough to vibrate to realize material conveying. The vibration frequency control range is preferably 15-25 Hz, and the feeding speed is preferably controlled at 2-5 t / h. Preliminary screening is carried out at the same time during feeding, and fine powder with a particle size of less than 3 mm is removed. The principle of this is that fine powder is easy to cause material agglomeration and equipment blockage, affecting the stability of the subsequent process. Then step S12 multi-stage particle size accurate screening is performed, using three layers of vibrating screen mesh for classification treatment, the first layer of screen mesh aperture is set to 20 mm, mainly used for screening out oversized particles; the second layer of screen mesh aperture is 5 mm, used for removing small particles; the third layer of screen mesh ensures that particles within the range of 5-20 mm pass through and are quality graded. The screening efficiency is required to be above 95%. Oversized particles will not be wasted, but will be re-entered into the screening system after crushing treatment, forming a closed circuit, and improving the raw material utilization rate. Step S13 two-stage magnetic separation deep purification is a special process for removing ferromagnetic impurities. Magnetic separation is a method of separation using the magnetic difference of substances. First, a low-intensity magnetic separator is used for treatment, with a magnetic field strength preferably controlled within the range of 800-1200 Gauss; then a high-intensity magnetic separator is used for further treatment, with a magnetic field strength preferably of 8000-12000 Gauss. The magnetic separation speed is controlled at 0.5-1.0 m / s, and through the synergistic effect of two-stage magnetic separation, the total content of iron impurities is reduced to below 0.015%, providing high-purity limestone base raw materials for the subsequent process.

[0078] Step S2 plasma surface pretreatment; the plasma surface pretreatment improves the particle surface properties through physical and chemical dual effects. In step S21 plasma field establishment, a dielectric barrier discharge device is used to generate low-temperature atmospheric pressure plasma. Dielectric barrier discharge (DBD) is a technology that inserts a dielectric barrier layer between two electrodes and generates a discharge phenomenon under the action of a high-frequency high-voltage electric field. The device power is preferably controlled at 1.5-2.0 kW, wherein kW is the power unit kilowatt; the working voltage is set to 3-5 kV, wherein kV is the voltage unit kilovolt; the discharge frequency is 20-50 kHz; the plasma generator adopts a flat plate electrode structure in the form of a ring and is uniformly distributed to ensure the uniformity and stability of the plasma field. In step S22 particle surface micro-modification process, the residence time of limestone particles in the plasma field is preferably controlled at 30-60 seconds. The plasma contains a large number of active particles such as high-energy electrons, ions and free radicals, and these high-energy particles have complex physical and chemical effects with the particle surface. The bombardment of high-energy electrons can effectively remove the organic contaminants and oxidation layer on the surface, while increasing the surface roughness by 15%-25% and increasing the specific surface area of the particles, thereby providing more active sites for subsequent reactions. Step S23 lattice defect activation treatment is a deep effect of plasma treatment. The high-energy bombardment of plasma generates various lattice defects such as point defects and line defects in the limestone lattice, and the defect density increases to 3-5 times compared with the original state. These lattice defects become high-activity reaction sites, significantly improving the reaction activity of the material and increasing the decomposition reaction rate of the subsequent calcination reaction by 30%-50%, thereby significantly improving the overall calcination effect.

[0079] Step S3 staged atmosphere calcination; the staged atmosphere calcination realizes high-quality lime production through precise temperature and atmosphere control. Step S31 waste heat preheating and temperature rising fully embodies the concept of comprehensive utilization of energy. In the preheating section of 400-600℃, the high-temperature flue gas at the kiln tail is used to indirectly heat through a plate heat exchanger. The plate heat exchanger is made of a series of metal sheets with a certain corrugated shape and has the characteristics of high heat transfer efficiency and compact structure. The high-temperature flue gas waste heat at the kiln tail of 1000-1200℃ is used to uniformly raise the material temperature to 580-620℃ through indirect heat exchange, and the heat exchange efficiency can reach 75%-85%. This waste heat utilization method saves fuel consumption by 15%-20% and realizes the cascade utilization of energy. Step S32 oxygen-enriched decarburization pretreatment; in the decarburization preheating section of 600-900℃, oxygen-enriched gas is introduced. Oxygen-enriched gas refers to a gas mixture with an oxygen content higher than 21% in air. The oxygen content of the introduced oxygen-enriched gas is preferably controlled at 25%-30%, and the flow rate is controlled at 100-150 Nm 3 / h, wherein Nm 3 / h. In this oxygen-rich environment, calcium carbonate begins to decompose, the chemical reaction is CaCO3→ CaO + CO2, and the decomposition rate can reach 20%-35% in this stage, and the released CO2 concentration reaches 15%-25%. Such pre-decomposition reduces the reaction load of the subsequent deep calcination stage. Step S33 weak reduction primary calcination uses precise atmosphere control technology. In the primary calcination stage at 900-1100°C, a weak reducing atmosphere with a CO concentration of 1%-3% is used, where CO is the chemical molecular formula of carbon monoxide. The weak reducing atmosphere is achieved by controlling the air excess coefficient α, and the calculation formula of the air excess coefficient is actual air amount / theoretical air amount; the actual air amount is the actual air amount supplied, and the unit is Nm 3 / h; the theoretical air amount is the theoretical air amount required for complete combustion of fuel, and the unit is Nm 3 / h. The preferred air excess coefficient control range is 0.95-0.98. This weak reducing atmosphere effectively inhibits the further oxidation of impurities such as Fe2O3 and Al2O3, while increasing the calcium carbonate decomposition rate to 70%-85%. Step S34 high-temperature oxidation atmosphere deep calcination is the final process to ensure complete decomposition. In the deep calcination stage at 1100-1250°C, an oxidation atmosphere is used, and the oxygen concentration is preferably controlled at 18%-20%, and the material residence time is controlled at 45-60 minutes. Under this high-temperature strong oxidation condition, the residual calcium carbonate is completely decomposed, and the final decomposition rate can reach more than 98.5%, and high-quality calcium oxide products with a purity of ≥98.5% are obtained.

[0080] Step S4 sound wave enhanced mass transfer; sound wave enhanced mass transfer significantly improves the mass and heat transfer effect through the physical action of sound waves. Step S41 secondary sound wave mass transfer promotion uses the deep penetration characteristics of the secondary sound wave. The secondary sound wave is a sound wave with a frequency lower than 20Hz, and the secondary sound wave with a frequency of 35-45Hz and a sound pressure level of 80-100dB is applied in the calcination temperature range of 900-1250°C. Sound pressure level is the logarithmic representation of sound pressure effective value relative to reference sound pressure, and the unit is dB. The secondary sound wave generator is installed on the outer wall of the calcination stage by electromagnetic excitation, and the sound wave penetrates into the particle interior to a depth of 5-8mm. The low-frequency mechanical vibration promotes the diffusion and mass transfer of CO2 gas in the particle interior, increases the mass transfer coefficient by 25%-40%, and accelerates the reaction gas removal process. Step S42 ultrasonic surface activation uses the cavitation effect of ultrasonic waves. Ultrasonic waves are sound waves with a frequency higher than 20kHz, and a frequency of 18-22kHz and a sound power density of 2-5W / cm 2The ultrasonic wave generator uses a piezoelectric ceramic transducer, a functional material that converts electrical energy into mechanical energy. The transducers are uniformly distributed in a ring on the inner wall of the calcination section. The ultrasonic waves generate a cavitation effect on the particle surface. Cavitation refers to the phenomenon where bubbles are generated, grow, and burst under the action of ultrasonic waves. Although the mechanism is slightly different in high-temperature solid systems, it can still produce a strong mechanical effect. This effect accelerates the exfoliation of the surface reaction product CaO, increasing the reaction rate constant by 35%-50%. Step S43, synergistic enhancement and optimization using infrasound, demonstrates the technical advantages of multi-physics coupling. Under the synergistic effect of infrasound and ultrasonic waves, the calcination reaction time can be shortened by 20%-30%, and the product activity can be increased to 360-400 mL. Activity is an important indicator for measuring the reactivity of calcium oxide, usually expressed as the time consumed by 4N hydrochloric acid to neutralize calcium oxide. Simultaneously, product uniformity is significantly improved, with the standard deviation reduced to within ±5%, achieving a highly efficient and uniform calcination process.

[0081] Step S5: Comprehensive utilization and intelligent control of thermal energy; including step S51: Real-time data acquisition and monitoring, which establishes a complete sensor network. Key process parameters are collected at 1-second intervals using various sensors distributed throughout the calcining kiln. Temperature sensors collect temperatures from each section. , , , Pressure sensors collect pressure data at various points. , , , The gas composition analyzer collects oxygen concentration. and carbon dioxide concentration Flow sensor collects fuel flow and airflow This real-time data provides an accurate data foundation for intelligent control systems, while historical data is stored in the process database, forming a source of training data for machine learning algorithms.

[0082] Step S52, data preprocessing and feature extraction, employs advanced signal processing techniques. The acquired raw data undergoes filtering and noise reduction, using a Kalman filter algorithm to eliminate measurement noise. The Kalman filter is a highly efficient recursive filter capable of estimating the state of a dynamic system from a series of noisy measurements. The filtering formula is:

[0083] ;

[0084] in, This is the optimal estimate at time k; The predicted value at time k; Let K be the Kalman gain matrix at time k; is the observation value at time k; is the observation matrix; the vertical bar symbol represents the estimate under given conditions; the square brackets represent vector subtraction operations. Then the temperature gradient , pressure fluctuation ΔP, etc. dynamic characteristic parameters are extracted, where d represents the differential operator, t represents the time variable, and Δ represents the change amount. These characteristic parameters better reflect the dynamic characteristics of the process.

[0085] The machine learning model training and updating in step S53 adopts a deep neural network algorithm. The deep neural network DNN (Deep Neural Network) is an artificial neural network containing multiple hidden layers. The network structure of the present application is designed as 20 neurons in the input layer, 64 neurons in the first hidden layer using the ReLU activation function, ReLU being Rectified Linear Unit, the mathematical expression being ; 128 neurons in the second hidden layer using the LeakyReLU activation function, LeakyReLU being an improved version of ReLU, the expression being , where alpha is a small positive number; 64 neurons in the third hidden layer using the ELU activation function, ELU being Exponential Linear Unit; 12 neurons in the output layer corresponding to fuel flow, air flow in each section, ORC pump speed, and cooling water flow control parameters. The loss function adopts the mean square error: ; the optimizer adopts the Adam algorithm, the learning rate is set to 0.001, the model is trained using the historical operation database, the training set and the validation set are divided according to 8:2, the feature selection is performed through the principal component analysis method, and the prediction accuracy of the validation set reaches more than 95%; MSE is the mean square error; n is the sample number; is the true value of the i-th sample; is the predicted value of the i-th sample; ∑ is the summation symbol; i is the sample index; the optimizer adopts the Adam algorithm, Adam being Adaptive Moment Estimation, which is a stochastic optimization method based on first-order and second-order moment estimation. The feature selection method adopts the principal component analysis method PCA (Principal Component Analysis), which projects the original features to a low-dimensional space through linear transformation and retains the most important information. The model is automatically updated every 24 hours to ensure that the latest process state is always reflected.

[0086] The optimal parameter calculation and prediction in step S54 establishes a multi-objective optimization framework. The product purity , activity , and energy consumption are taken as optimization objectives, and a comprehensive evaluation function is established:

[0087] ;

[0088] wherein F is the comprehensive evaluation function; 、 、 are weight coefficients, which can be adjusted according to actual requirements; the plus sign represents a positive optimization goal, and the minus sign represents a negative optimization goal. The optimal fuel flow rate is calculated by a neural network mapping function:

[0089] and the optimal air flow rate ; wherein and are trained neural network mapping functions that predict the optimal control parameters according to the current process state.

[0090] Step S55 adopts a classic PID control algorithm for dynamic parameter automatic regulation;

[0091] PID, which stands for Proportional-Integral-Derivative, is a controller commonly used in industrial control. The fuel control output is: ;

[0092] wherein is the fuel controller output; is the fuel proportional gain; is the fuel control error; is the fuel integral gain; is the fuel derivative gain; d represents the differential operator; and t represents the time variable. Similarly, the air control output also adopts the same PID control structure.

[0093] Step S56 adopts an organic Rankine cycle technology for waste heat comprehensive recovery and utilization. The organic Rankine cycle (ORC) is a technology that uses organic working fluids to replace water for low-temperature waste heat power generation. The ORC system includes four basic components: an evaporator, a turbine generator, a condenser, and a working fluid circulating pump. R245fa is used as the working fluid, which is a low-boiling organic working fluid suitable for medium and low-temperature waste heat recovery. The power generation power calculation formula is: ; wherein is the power generation power, with a unit of kW; is the ORC system efficiency; is the flue gas mass flow rate, with a unit of kg / s; is the specific heat capacity of flue gas, with a unit of kJ / kg·K; ΔT is the temperature difference, with a unit of K; and the multiplication sign represents multiplication.

[0094] Step S6 rapid cooling; rapid cooling is a key process to maintain high activity of the product, and the best effect is achieved by combining various cooling techniques. Step S61 nanofluid rapid cooling uses advanced heat transfer enhancement technology. Nanofluid refers to a new type of heat transfer working medium formed by suspending nanoscale particles in traditional fluid. Al2O3, H2O nanofluid is used as the cooling medium, wherein Al2O3 represents alumina nanoparticles, and H2O represents water-based fluid. The concentration of nanoparticles is preferably controlled at 1%-3%vol, vol is the abbreviation of volume. Nanoparticles are prepared by ultrasonic dispersion technology, which uniformly disperses nanoparticles in liquid by using ultrasonic cavitation and mechanical vibration, and adds a surfactant as a stabilizer to maintain dispersion stability. High-temperature calcium oxide is sprayed and cooled by a high-pressure nozzle at a pressure of 3-5 MPa. The heat transfer coefficient of nanofluid is increased by 20%-30% compared with pure water. This heat transfer enhancement effect makes the material temperature quickly drop to 600-700℃. Step S62 circulating forced air cooling is the second stage of cooling process. After nanofluid spraying cooling, the forced air cooling system is started immediately, the wind speed is controlled at 15-20 m / s, and the wind temperature is controlled at 30-50℃. Forced air cooling uses large volume of cold air to take away the heat on the surface of the material, and the cooling time is 90-120 seconds, which further reduces the material temperature to 150-200℃. This phased cooling strategy effectively controls the cooling rate and avoids thermal stress cracking caused by rapid cooling. Step S63 inert atmosphere protection cooling ensures that the product does not react during the cooling process. N2 or Ar and other inert gases are introduced for atmosphere protection, inert gas is a gas with extremely low chemical activity, which does not react with other substances. The gas flow is controlled at 50-80 Nm 3 / h, which realizes rapid cooling within 2-3 minutes of total cooling time, prevents the reaction of calcium oxide with CO2 and H2O in the air, and maintains the high-quality indicators of product purity ≥98.5% and activity ≥360 mL.

[0095] Step S7 flue gas treatment; flue gas treatment is an important link to achieve environmental protection emission and resource recycling. Step S71 flue gas cooling purification pretreatment establishes a multi-stage treatment system. The high-temperature flue gas of 1000-1200℃ generated in the calcination process is cooled by three-stage series heat exchangers in turn, the first stage is reduced to 800℃, the second stage is reduced to 400℃, and the third stage is reduced to 200-250℃, and the heat exchange efficiency of each stage is 80%, 75% and 70% respectively. Then, the primary dust removal is carried out by a cyclone dust collector, which is a device that separates dust by centrifugal force generated by airflow rotation; then, the fine dust removal is carried out by a bag dust collector, which is a device that filters dust-containing gas by using fiber filter material, and the total dust removal efficiency is more than 95%. Finally, SO2 is removed by a desulfurization tower, and the desulfurization efficiency is ≥90%. Step S72 efficient CO2 separation and capture uses chemical absorption method. 30wt% ethanolamine solution is used as absorbent, and wt% represents mass percentage. Ethanolamine, English abbreviation MEA (Monoethanolamine), chemical molecular formula HOCH2CH2NH2, is an organic amine compound with good CO2 absorption capacity. In the packed absorption tower, it is countercurrently contacted with the purified flue gas to achieve the best mass transfer effect. The operating pressure of the absorption tower is preferably 0.1-0.15 MPa, and the temperature is controlled at 40-60℃, and the liquid-gas ratio L / G=3-5, wherein L is the liquid phase flow rate, unit L / h; G is the gas phase flow rate, unit Nm 3 / h; the oblique line represents the ratio. The CO2 absorption efficiency can reach 85%-92%, and the CO2-rich solution is regenerated at 120-130℃ by a desorption tower, which is the reverse process of absorption. The dissolved CO2 is released from the solution by heating. Step S73 CO2 high-value resource utilization realizes waste resource. The captured CO2 is compressed to 5 MPa by a compressor and then transported to the downstream utilization device. According to market demand, different utilization paths can be selected, which is reacted with CaO to prepare nano calcium carbonate, and the reaction formula is CaO+CO2+H2O→CaCO3+H2O. Another is transported to a methanol synthesis device, and reacted with H2 (hydrogen) to synthesize methanol under the action of Cu-Zn-Al catalyst, and the reaction formula is CO2+3H2→CH3OH+H2O, wherein CH3OH represents methanol, which is a hydrogenation reaction process.

[0096] Step S8 finished product packaging; finished product packaging is the last link to ensure product quality stability. Step S81 fully closed inert atmosphere conveying adopts strict atmosphere control. The cooled calcium oxide product is conveyed by a closed screw conveyor, the conveying pipeline is filled with N2 inert gas with a purity of ≥99.5%, the pressure is controlled at 0.05-0.1 MPa, and the oxygen content is strictly controlled below 0.1%. This fully closed conveying method completely isolates air contact, prevents the product from absorbing moisture and carbonation reaction, and maintains the original high purity and high activity state of the product. Step S82 indirect cooling to room temperature adopts tube and shell heat exchange technology. The tube and shell indirect cooler is a commonly used indirect heat exchange equipment, the cooling medium is circulating cooling water, the inlet water temperature is controlled at 20-25℃, the outlet water temperature is 35-40℃, and the cooling effect is adjusted by controlling the cooling water flow. The cooling time is 30-45 minutes, the product temperature is reduced to within +5℃ of the ambient temperature, and the safety of the packaging process and the stability of the long-term storage of the product are ensured. Step S83 automatic quantitative sealing packaging adopts modern packaging technology. Precise weighing is carried out through an electronic scale, the packaging accuracy is ±0.3%, and the packaging specifications can be selected as 25 kg woven bags or 1000 kg ton bags and other different specifications. The three-layer composite moisture-proof packaging material of PE inner bag + woven bag outer layer + moisture-proof film has good moisture-proof performance. The automatic sealing machine adopts double sealing technology of heat sealing + ultrasonic sealing, the heat sealing temperature is set to 160℃, and the ultrasonic power is 800W. After packaging, dry N2 gas is filled, the filling pressure is 0.02 MPa, the filling time is 15 seconds, the oxygen content in the bag is controlled below 0.1%, the water content of the product is controlled below 0.5%, the activity decay is less than 5% within 24 months of storage, and the long-term storage quality stability of the product is realized. Through the precise cooperation and coordinated execution of the above steps, the process stably produces high-quality calcium oxide products with a purity of ≥98.5% and an activity of ≥360 mL, while achieving multiple goals of energy comprehensive utilization and environmental protection emission.

[0097] The application also designs a high-purity lime manufacturing system, comprising: a raw material pretreatment unit arranged at the feeding end of the system, including an electromagnetic vibration feeder, a three-layer vibration screen separator and a double-stage magnetic separation device connected in series, to realize uniform feeding, accurate screening and deep iron removal and purification of the limestone raw material; a plasma surface pretreatment unit connected with the outlet of the raw material pretreatment unit through a closed conveying pipeline, including a dielectric barrier discharge plasma generator, a quartz glass treatment chamber and a variable frequency speed material conveying device, to perform surface modification and activity excitation on the limestone particles; a multi-section gradient atmosphere calcination kiln connected with the outlet of the plasma surface pretreatment unit through a feeding port, being a vertical multi-section kiln body structure, including a preheating section, a decarburization section, a primary calcination section, a deep calcination section and a quenching section arranged from top to bottom, to realize gradient heating and complete decomposition of the limestone; a sound wave reinforced mass transfer system embedded and installed in the inner walls of the primary calcination section and the deep calcination section of the multi-section gradient atmosphere calcination kiln, to reinforce the mass transfer and heat transfer process through the synergistic effect of infrasonic waves and ultrasonic waves; a heat energy comprehensive utilization and intelligent control system connected with each section of the multi-section gradient atmosphere calcination kiln through signal cables and control pipelines, including a distributed sensor network, a central data processing unit, a machine learning optimization module, a distributed control execution unit and a waste heat recovery device, to realize intelligent optimization of process parameters and comprehensive utilization of energy; a CO2 capture and resourceization unit connected with the flue gas outlet of the multi-section gradient atmosphere calcination kiln through a flue gas main pipeline, including a multi-stage heat exchanger, a dust removal and purification device, a CO2 absorption and separation device and a CO2 utilization device arranged in series, to realize flue gas purification and CO2 capture and resourceization; a finished product cooling and packaging unit connected with the material outlet of the quenching section of the multi-section gradient atmosphere calcination kiln through a closed pipeline, including an inert atmosphere conveying system, an indirect cooling device and an automatic packaging equipment, to ensure product quality maintenance and automatic packaging.

[0098] The raw material pretreatment unit comprises: an electromagnetic vibration feeder adopting a double-mass forced vibration structure, a variable frequency motor and a vibration force adjustable mechanism, a vibration frequency of 15-25 Hz, a feeding capacity of 2-5 t / h, a screen pre-separation device for removing fine powder with a particle size of less than 3 mm to prevent the subsequent equipment from being blocked; a three-layer vibrating screen separator adopting a linear vibrating screen structure, a first layer of screen aperture of 20 mm and an inclination angle of 15° for screening out oversized particles, a second layer of screen aperture of 5 mm and an inclination angle of 20° for screening out small particles, and a third layer of screen for ensuring that the 5-20 mm particles pass through and are subjected to quality grading, and an inclination angle of 18°, the screen separator being provided with a rubber ball screen cleaning device to prevent the screen from being blocked, and a screening efficiency of greater than or equal to 95%; an oversized particle crushing and backflow system comprising a jaw crusher, a vibrating feeder and a backflow belt conveyor, which crushes oversized particles to qualified particle size and then re-enters the screening system to form a closed circuit; a two-stage magnetic separation device, the first stage being a low-intensity magnetic separator with a magnetic field strength of 800-1200 Gauss, a permanent magnet roller structure and a magnetic separation speed of 0.5-1.0 m / s for removing weakly magnetic impurities, and the second stage being a high-intensity magnetic separator with a magnetic field strength of 8000-12000 Gauss, an electromagnetic inductor structure and an automatic iron unloading device to reduce the total content of iron impurities to below 0.015%; a quality detection and feedback system comprising an online particle size analyzer, an iron content detector and an automatic sampling device for real-time monitoring of the raw material quality and feedback control of the screening and magnetic separation parameters to ensure stable discharge quality.

[0099] The plasma surface pretreatment unit comprises: a dielectric barrier discharge plasma generator adopting a flat plate electrode structure, a stainless steel working electrode, an alumina ceramic dielectric barrier, an electrode spacing of 2-3 mm, a high-frequency high-voltage power supply with a power of 1.5-2.0 kW, a working voltage of 3-5 kV and a discharge frequency of 20-50 kHz adjustable to generate uniform and stable low-temperature atmospheric pressure plasma; a quartz glass treatment chamber adopting a cylindrical structure with an inner diameter of 300 mm, a length of 1200 mm and a wall thickness of 8 mm, a high-purity quartz glass material with excellent dielectric properties and chemical stability, and a uniformly distributed electrode array arranged in the chamber to ensure uniform plasma field distribution; a variable frequency speed material conveying device comprising a screw conveyor, a variable frequency motor and a speed controller, a conveying speed of 0.1-0.5 m / s adjustable to ensure that the limestone particles stay in the plasma field for 30-60 seconds, and a vibration device arranged to prevent material sticking and bridging; an atmosphere control system comprising an inert gas supply pipeline, a flow control valve and a pressure regulator, which can introduce N2 or Ar gas to maintain an inert atmosphere in the treatment chamber to prevent particle oxidation, and a waste gas collection and treatment device arranged; a power control and monitoring system comprising a digital controller, a current and voltage monitor and a fault protection device to realize accurate control and safe operation of the plasma generator, and to have overcurrent, overvoltage and overheating protection functions.

[0100] The multi-stage gradient atmosphere calcination kiln comprises: a kiln body main structure, which adopts a vertical multi-stage structure, has a total height of 15-20 m, an inner diameter of 1.5-2.0 m, is made of high-temperature refractory steel, is coated with multiple layers of refractory insulation material, has an insulation layer thickness of 200-300 mm, effectively reduces heat loss, and is provided with gas pipelines and signal connection interfaces between units; a preheating section, which is located at the upper part of the kiln body, has a height of 3-4 m, is internally provided with a heat exchanger tube bundle, indirectly preheats by using high-temperature flue gas at the kiln tail, is provided with a plate heat exchanger, has a heat exchange area of 50-60 m 2 , a heat exchange efficiency of 75-85%, and makes the material temperature rise to 580-620℃; a decarburization section, which is located below the preheating section, has a height of 2-3 m, is provided with an oxygen-rich gas injection device, and comprises an oxygen supply pipeline, a flow control system and a nozzle array, has an oxygen content of 25-30%, a flow of 100-150 Nm 3 / h, and promotes the preliminary decomposition of calcium carbonate; a primary calcination section, which has a height of 3-4 m, is provided with a burner assembly, comprises a main burner, an auxiliary burner and an air excess coefficient control system, realizes a weak reducing atmosphere by accurately controlling the fuel and air ratio, and has a CO concentration of 1-3%; a deep calcination section, which has a height of 4-5 m, is provided with a high-temperature combustion system, comprises a multi-point distributed burner, a temperature partition control device and an atmosphere adjusting system, ensures a temperature of 1100-1250℃, an oxygen concentration of 18-20%, and a material residence time of 45-60 minutes; a rapid cooling section, which is located at the bottom of the kiln body, has a height of 1-2 m, is provided with a rapid cooling device, comprises a nanofluid spraying system and a forced air cooling system, and realizes rapid cooling to 150-200℃ within 2-3 minutes; a material conveying and sealing system, which comprises a star-shaped discharger, a sealing gate valve and a material conveying pipeline, ensures smooth transition of the material between sections and atmosphere isolation.

[0101] The sound wave reinforced mass transfer system comprises: an infrasound wave generator, which is installed on the outer wall of the primary calcination section and the deep calcination section, adopts electromagnetic excitation, has a frequency of 35-45 Hz, an adjustable sound pressure level of 80-100 dB, is provided with a power amplifier and a frequency regulator, and has a penetration depth of 5-8 mm into the particle interior; and an ultrasonic wave generator array, which is distributedly installed in the refractory material of the inner wall of the calcination section, adopts a piezoelectric ceramic transducer, has a frequency of 18-22 kHz, and has a sound power density of 2-5 W / cm 2, transducer quantity 12-16, annular uniform distribution; sound wave transmission medium, using special high-temperature sound wave transmission material, ensuring effective transmission of sound waves to the material inside, the material is silicon nitride ceramic composite material, the working temperature can reach 1300 DEG C; sound wave control system, including digital signal generator, power amplifier, phase controller and synchronous control unit, realizing the coordination of infrasound and ultrasonic waves, and adjusting the sound wave parameters according to the process requirements; effect monitoring device, including sound wave sensor, temperature sensor and reaction rate detector, real-time monitoring of sound wave intensification effect, feedback adjustment of sound wave parameters, ensuring the optimal mass transfer intensification effect.

[0102] The heat energy comprehensive utilization and intelligent control system comprises: a distributed sensor network comprising a temperature sensor array, a pressure sensor group, a gas component analyzer group and a flow sensor network, a total number of sensors being 80-100, distributed at key positions of the calcination kiln, a collection frequency being 1 Hz, and data transmission adopting an industrial Ethernet protocol; a central data processing unit adopting a high-performance industrial computer, configured with a multi-core CPU, a large-capacity memory and a high-speed storage device, having real-time data collection, storage, processing and analysis capabilities, and a data processing capability being greater than or equal to 10000 points per second; a machine learning optimization module comprising a deep neural network server, a historical operation database and a model automatic updating system, having a five-layer network structure of 20-64-128-64-12, adopting GPU accelerated calculation, a model training and prediction response time being less than 5 seconds, and having a fault diagnosis function; a distributed control execution unit comprising a PID controller group, an electric regulating valve, a frequency converter and an actuator, a control point number being 60-80, a control precision being ±2%, a response time being less than or equal to 30 seconds, and having a manual / automatic switching and fault safety function; a waste heat recovery device comprising an organic Rankine cycle power generation system and a hot water preparation system, the ORC system comprising an evaporator, a turbine generator, a condenser and a working medium circulating pump, adopting R245fa working medium, a power generation power being 50-80kW, and a hot water preparation capacity being 10-15m 3 / h; a man-machine interface adopting a large-screen display and a touch operation panel, having process flow display, parameter monitoring, alarm management and historical trend analysis functions, and supporting remote monitoring and diagnosis.

[0103] The CO2 capture and resource utilization unit comprises: a multi-stage heat exchanger group comprising three-stage series heat exchangers, the first stage being a high-temperature heat exchanger, the material being heat-resistant alloy, the heat exchange area being 30-40m 2 , the flue gas temperature being reduced from 1000-1200 DEG C to 800 DEG C; the second stage being a medium-temperature heat exchanger, the material being stainless steel, the heat exchange area being 25-35m 2 , the flue gas temperature being reduced to 400 DEG C; and the third stage being a low-temperature heat exchanger, the material being carbon steel, the heat exchange area being 20-30m 2The flue gas temperature is reduced to 200-250℃; the dust removal and purification device includes a cyclone dust collector and a bag dust collector, the cyclone dust collector has a diameter of 1.5 m and a height of 6 m, and a dust removal efficiency of 80-85%; the bag dust collector adopts PTFE membrane filter bag, a filter area of 200-300 m 2 , and a dust removal efficiency of ≥99.5%; the desulfurization tower adopts a wet desulfurization process, has a tower diameter of 2 m and a height of 8 m, and a desulfurization efficiency of ≥90%; the CO2 absorption and separation device includes a filler absorption tower, a desorption tower and a solution circulation system, the absorption tower has an inner diameter of 1.8 m and a height of 12 m, the filler is metal hole plate corrugated filler with a specific surface area of 250 m 2 / m 3 ; the desorption tower has an inner diameter of 1.5 m and a height of 10 m, and is provided with a reboiler and a condenser; the MEA solution storage tank has a volume of 10 m 3 , and a circulating pump flow of 800 L / h; the CO2 compression and storage system includes multi-stage centrifugal compressors, an intermediate cooler and a gas storage tank, the compressor has a power of 200 kW, a final pressure of 5 MPa, and the gas storage tank has a volume of 50 m 3 and is made of low alloy steel; the CO2 utilization device includes a calcium carbonate preparation reactor and a methanol synthesis reactor, the calcium carbonate preparation reactor is a stirred tank reactor with a volume of 3 m 3 , and is provided with a stirrer, a cooling system and a pH control device; the methanol synthesis reactor is a fixed bed reactor with an inner diameter of 0.8 m and a height of 4 m, and is filled with Cu-Zn-Al catalyst.

[0104] The finished product cooling and packaging unit includes: an inert atmosphere conveying system including a closed screw conveyor, an N2 supply system and an atmosphere control device, the screw conveyor has a length of 20 m, an inner diameter of 300 mm and is made of stainless steel, and has a conveying capacity of 3-5 t / h; the N2 supply system includes a nitrogen generator, a purification device and a flow controller, the N2 purity is ≥99.5%, and the supply capacity is 100 Nm 3 / h; the nanofluid spraying cooling system includes a nanofluid preparation device, a high-pressure spraying system and a circulation and recovery system, the nanofluid preparation device adopts ultrasonic dispersion technology combined with a surfactant for stabilization, the Al2O3 nanoparticle concentration is 1-3 vol%; the high-pressure pump has a pressure of 3-5 MPa, 12 nozzles are annularly distributed; the forced air cooling system includes a centrifugal fan, a cooling air duct and a temperature control device, the fan has an air volume of 3000 m 3 / h, the air duct adopts a spiral structure to ensure uniform cooling; the temperature control system can adjust the air temperature to 30-50℃; the indirect cooling device includes a tube-shell heat exchanger, a circulating water system and a temperature monitoring system, the heat exchanger has a heat exchange area of 15 m 2 , and the circulating water flow is 12 m 3 / h, cooling tower and water treatment device, automatic packaging equipment including electronic weighing system, packaging machine and sealing device, electronic weighing accuracy ±0.3%, packaging speed 20-30 packs / hour; the packaging machine uses three-layer composite packaging material, and the sealing device has heat sealing and ultrasonic double sealing functions; quality detection system including activity detector, purity analyzer and water content detector, realizing online detection and automatic grading packaging of finished product quality; N2 filling system including N2 purification device, pressure controller and filling head, filling pressure 0.02 MPa, filling time 15 seconds, ensuring that the oxygen content in the package is <0.1%.

[0105] In Example 1, a complete high-purity lime manufacturing process is used to verify the industrial application on a certain lime production line. The production line is designed to produce 300 tons of high-purity calcium oxide per day. The raw material used is high-quality limestone from Hebei area, with a CaCO3 content of 96.8%. The main impurities are SiO2 content of 1.2%, Fe2O3 content of 0.8%, Al2O3 content of 0.6%, MgO content of 0.4%, and other impurities of 0.2%. In the raw material pretreatment stage, an electromagnetic vibrating feeder with a vibration frequency of 20 Hz is used for continuous feeding, and the feeding speed is stably controlled at 3.5 t / h. Through a three-layer vibrating screen separator, the first layer of screen mesh with a pore size of 20 mm screens out oversized particles larger than 20 mm, accounting for about 8% of the total amount, the second layer of screen mesh with a pore size of 5 mm screens out fine particles smaller than 5 mm, accounting for about 12% of the total amount, and the third layer of screen mesh ensures that particles within the range of 5-20 mm pass through, with qualified particles accounting for 80% of the total amount. In the double-stage magnetic separation device, the low-intensity magnetic separator is set to a magnetic field strength of 1000 Gauss and a magnetic separation speed of 0.8 m / s to remove weakly magnetic impurities, and the high-intensity magnetic separator is set to a magnetic field strength of 10000 Gauss and a magnetic separation speed of 0.6 m / s to remove strongly magnetic impurities. After double-stage magnetic separation, the total iron impurity content is reduced from 0.8% in the raw material to 0.012%. The plasma surface pretreatment unit uses a dielectric barrier discharge device with a power of 1.8 kW, a working voltage of 4 kV, and a discharge frequency of 35 kHz. The residence time of limestone particles in the plasma field is controlled at 45 seconds, and the surface roughness of the treated particles increases by 20% compared to the original particles, and the lattice defect density increases to 4 times the original, providing more active sites for subsequent calcination reactions. The temperature of each section of the multi-section gradient atmosphere calcination kiln is accurately controlled. The preheating section is controlled at 580°C, and the high-temperature flue gas at 1150°C at the kiln tail is used for indirect preheating through a plate heat exchanger, with a heat exchange efficiency of 82%. The decarburization section is controlled at 850°C, and oxygen-enriched gas with an oxygen content of 28% is introduced, with a flow rate of 125 Nm 3h, promote the preliminary decomposition of calcium carbonate, the decomposition rate reached 30%; the temperature control in the primary calcination stage was 1050℃, a weak reducing atmosphere with CO concentration of 2% was adopted, the air excess coefficient a was controlled at 0.96, and the calcium carbonate decomposition rate reached 78%; the temperature control in the deep calcination stage was 1200℃, an oxidizing atmosphere with oxygen concentration of 19% was adopted, the material residence time was 52 minutes, and the final decomposition rate reached 98.8%. The sound wave intensification mass transfer system worked simultaneously in the primary calcination stage and the deep calcination stage, the infrasonic wave generator produced infrasonic waves with a frequency of 40 Hz and a sound pressure level of 90 dB, and the penetration depth reached 6 mm inside the particles; the ultrasonic wave generator produced ultrasonic waves with a frequency of 20 kHz and a sound power density of 3.5 W / cm 2 Under the synergistic effect of sound waves, the calcination reaction time was shortened by 25%, and the mass transfer coefficient was increased by 35%.

[0106] The thermal energy comprehensive utilization and intelligent control system collected the process parameters of 90 monitoring points in real time through a distributed sensor network, with a collection frequency of 1 Hz. The deep neural network model adopted a five-layer structure of 20-64-128-64-12, and the historical operation database contained 150,000 records of continuous operation data for 6 months, with a prediction accuracy of 96.5% for the validation set. The organic Rankine cycle power generation system utilized high-temperature flue gas waste heat, with an actual power generation of 65 kW, and produced 85℃ process hot water at a rate of 12 m 3 / h. The rapid cooling system used Al2O3 / H2O nanofluid for spray cooling, with a nanoparticle concentration of 2.5vol%, a spray pressure of 4 MPa, and a spray time of 40 seconds, which reduced the material temperature from 1200℃ to 650℃. Subsequently, the forced air cooling system was started, with a wind speed of 18 m / s and a wind temperature of 40℃, and the cooling time was 105 seconds, which further reduced the material temperature to 180℃. The entire cooling process was carried out in an inert atmosphere, with a N2 gas flow rate of 65 Nm 3 / h. The flue gas treatment system gradually reduced the flue gas temperature from 1150℃ to 220℃ through a three-stage series heat exchanger, and the total dust removal efficiency of the dust removal system reached 97.5%, and the desulfurization efficiency reached 92%. The CO2 separation and capture system used 30wt% MEA solution to realize countercurrent contact in the packed absorption tower, with an operating pressure of 0.12 MPa, a temperature of 50℃, and a liquid-gas ratio of 4, the CO2 absorption efficiency reached 90%, and the purity of recovered CO2 reached 96.5%. The finished product packaging system was carried out in a completely sealed inert atmosphere, with a N2 purity of 99.6% in the conveying pipeline, a pressure of 0.08 MPa, and an oxygen content controlled below 0.08%. After indirect cooling to room temperature, three-layer composite moisture-proof packaging materials were used, dry N2 gas was filled, the filling pressure was 0.02 MPa, and the oxygen content in the bag was controlled below 0.06%. Through stable operation for 30 consecutive days, the high-purity calcium oxide products produced in this embodiment performed excellently in various indicators.

[0107] Comparative Example 1, Comparative Example 1 uses a traditional shaft lime production process as a conventional technology widely used in the industry. This process omits the plasma surface pretreatment step and directly sends the screened and magnetically separated limestone particles into a traditional shaft kiln for calcination. The raw material pretreatment stage only performs simple vibration screening and single-stage magnetic separation. The screening machine uses a two-layer screen structure with a screening efficiency of about 85%, and the magnetic separator uses a permanent magnet roller structure with a magnetic field strength of 800 Gauss. The total content of iron impurities can only be reduced to 0.025%. The calcination process uses a traditional shaft kiln with uneven temperature distribution. The highest temperature is 1100°C, the average temperature is 950°C, and the material residence time in the kiln is 180 minutes. Due to the lack of precise atmosphere control, the kiln is mainly in an oxidizing atmosphere with natural ventilation, and it is impossible to achieve weak reduction atmosphere primary calcination. The calcium carbonate decomposition rate is about 95.5%. The cooling method uses traditional natural air cooling with a cooling time of 4-6 hours. There is no inert atmosphere protection during the cooling process, and the product is prone to moisture absorption and carbonization reaction. The flue gas treatment only uses a simple cyclone dust collector with a dust removal efficiency of about 80%. There is no CO2 capture and resource utilization device, and all flue gas is directly discharged. The packaging process is carried out in a conventional atmospheric environment using ordinary woven bags without inert gas protection.

[0108] Comparative Example 2, Comparative Example 2 uses a rotary kiln improved process. The raw material pretreatment uses the same three-layer screening and double-stage magnetic separation as Example 1, and the total content of iron impurities is reduced to 0.013%. The calcination process uses a rotary kiln with relatively uniform temperature distribution. The highest temperature reaches 1180°C, and the material residence time is 90 minutes. The cooling method uses a water cooler for indirect cooling with a cooling time of about 2 hours, which is an improvement over the traditional shaft kiln, but the cooling efficiency is still lower than the nanofluid rapid cooling technology. The flue gas treatment uses a bag dust collector, but there is no CO2 capture device. The waste heat utilization is limited to preheating combustion air, and the power generation is zero. The packaging process uses semi-closed packaging with PE inner bags, but there is no inert gas protection, and the product storage stability is limited.

[0109] Comparative Example 3, Comparative Example 3 uses an integrated process with some advanced technologies, including multi-stage calcination and waste heat utilization, but does not use plasma pretreatment and sound wave mass transfer enhancement technology. The raw material pretreatment is exactly the same as Example 1, using three-layer screening and double-stage magnetic separation, and the total content of iron impurities is reduced to 0.012%. The calcination process uses a multi-stage vertical kiln structure to achieve temperature gradient control. The preheating section is 580°C, the decarburization section is 850°C, the calcination section is 1180°C, and the material residence time is 75 minutes. The waste heat utilization uses a simple heat exchanger to preheat the combustion air without an organic Rankine cycle power generation system, resulting in relatively low energy utilization efficiency. The flue gas treatment uses a dust removal and desulfurization device, but does not use CO2 capture and resource utilization. The cooling and packaging processes are basically the same as Example 1, using nanofluid rapid cooling and inert atmosphere packaging.

[0110] The product of each example and the comparative example was tested and analyzed for performance, including product quality index testing, which was performed in accordance with GB / T 5762-2012 “Chemical analysis methods for limestone, quicklime and hydrated lime for building materials”, and JC / T 479-2013 “Building quicklime”. The purity of calcium oxide was determined using EDTA complexometric titration in accordance with GB / T 5762-2012. 1.0000 g of the sample was dissolved with hydrochloric acid and then diluted to 250 mL. 25.00 mL of the sample solution was taken, sodium hydroxide solution was added to adjust the pH value to 12-13, calcium indicator was added, and 0.05 mol / L EDTA standard solution was added dropwise until the end point. The purity of the product of Example 1 was 98.92%, the purity of Comparative Example 1 was 94.85%, the purity of Comparative Example 2 was 97.65%, and the purity of Comparative Example 3 was 98.15%. The activity of calcium oxide was determined in accordance with the JC / T 479-2013 standard using a 4N hydrochloric acid neutralization method. 1.00 g of the sample, which was crushed to pass through a 0.9 mm sieve, was stirred with 40 mL of distilled water at 20°C to form a lime milk. Phenolphthalein indicator was added, and 4N hydrochloric acid standard solution was added dropwise until the red color disappeared. The consumption time and acid amount were recorded. The iron content was determined using the o-phenanthroline spectrophotometric method in accordance with the GB / T 5762-2012 standard. The water content was determined using the drying weight method in accordance with the JC / T 479-2013 standard, and the sample was dried to constant weight at a temperature of 105 ± 5°C. The energy consumption was determined in accordance with GB / T 2589-2020 “General rules for calculating comprehensive energy consumption”. The fuel consumption was continuously measured by a flow meter, the electric power consumption was measured by an electric energy meter, and the waste heat recovery amount was measured by a heat meter. The comprehensive energy consumption per unit product of Example 1 was 850 kgce / t, the comprehensive energy consumption of Comparative Example 1 was 1180 kgce / t, the comprehensive energy consumption of Comparative Example 2 was 1050 kgce / t, and the comprehensive energy consumption of Comparative Example 3 was 920 kgce / t, where ce represents standard coal equivalent.

[0111] The CO2 emission was determined in accordance with GB / T 32151.15-2015 “Requirements for accounting and reporting of greenhouse gas emissions”, including fuel combustion emissions and process emissions. The smoke emission concentration was determined in accordance with HJ 836-2017 “Determination of low concentration particulate matter from waste gas of fixed pollution sources by gravimetric method”. The SO2 emission concentration was determined in accordance with HJ 57-2017 “Determination of sulfur dioxide in waste gas of fixed pollution sources by constant potential electrolysis method”. The production efficiency index was tested, and the calcination reaction time was determined by online monitoring of the CO2 release rate. When the CO2 release rate decreased to less than 5% of the peak value, it was considered that the reaction was basically complete. The product quality stability was determined by continuous sampling and analysis, and the standard deviation of the calcium oxide purity was calculated. The waste heat power generation income was calculated according to the local industrial electricity price of 0.65 yuan / kWh. The annual waste heat power generation income of Example 1 was 350,000 yuan, Comparative Example 2 and Comparative Example 3 had no waste heat power generation, and Comparative Example 1 had no waste heat utilization. The experimental results are shown in Tables 1-3,Figures 1-6 The results are shown in Table 1.

[0112] Table 1 Comparison of product quality indicators

[0113]

[0114] Table 2 Comparison of energy consumption and environmental protection indicators

[0115]

[0116] Table 3 Comparison of production efficiency indicators

[0117]

[0118] Table 4 Comparison of economic benefit indicators

[0119]

[0120] As can be seen from Tables 1-4, in terms of product quality, the purity of calcium oxide produced in Example 1 reached 98.92%, which was 4.07 percentage points higher than that of Comparative Example 1, 1.27 percentage points higher than that of Comparative Example 2, and 0.77 percentage points higher than that of Comparative Example 3. In terms of activity, Example 1 reached 385 mL, which was 140 mL higher than that of Comparative Example 1, 65 mL higher than that of Comparative Example 2, and 27 mL higher than that of Comparative Example 3. These significant quality improvements were mainly due to the plasma surface pretreatment technology stimulating more reactive sites, the sound wave mass transfer enhancement technology promoting the full reaction, and the precise multi-stage atmosphere control ensuring the optimal reaction conditions. In terms of energy consumption and environmental protection, the comprehensive energy consumption per unit product of Example 1 was only 850 kgce / t, which was reduced by 28% compared with Comparative Example 1, 19% compared with Comparative Example 2, and 8% compared with Comparative Example 3. In terms of CO2 emissions, Example 1 was 1.65 tCO2 / t product and achieved 15% recycling, while the other comparative examples had no recycling and higher emissions. The emission concentrations of smoke and SO2 were significantly reduced, achieving the goal of clean production. In terms of production efficiency, the calcination reaction time of Example 1 was only 42 minutes, which was shortened by 77% compared with Comparative Example 1, 53% compared with Comparative Example 2, and 44% compared with Comparative Example 3. The product quality stability was significantly improved, with a purity standard deviation of only ±2.8%, which was much lower than that of the other comparative examples. The equipment operation stability also reached the highest level, with a comprehensive operation rate of 96.8%. The activity of Example 1 reached 385 mL, which was 140 mL higher than that of Comparative Example 1, with an increase of 57.1%. The mechanism of this significant increase in activity was that the plasma pretreatment increased the surface roughness of the particles by 15%-25%, significantly increasing the specific surface area and providing more active sites for subsequent reactions. The sound wave mass transfer enhancement technology promoted the rapid diffusion of CO2 gas inside the particles and the timely stripping of surface reaction products through the deep penetration of infrasound and the surface cavitation effect of ultrasonic waves, increasing the reaction rate constant by 35%-50%. The intelligent control system used a deep neural network algorithm to optimize process parameters in real time, ensuring accurate control of key parameters such as temperature, pressure, and gas composition during calcination, avoiding the lag and inaccuracy problems in manual or simple automatic control. The iron content of Example 1 was controlled at 0.011%, the moisture content was only 0.38%, and the product quality standard deviation was only ±2.8%, which reflected the precision and stability of the process control of the present application. The two-stage magnetic separation deep purification technology used a series configuration of low-intensity and high-intensity magnetic separators to remove weakly magnetic and strongly magnetic impurities, respectively, with the magnetic field strength increasing from 800-1200 Gauss to 8000-12000 Gauss, ensuring the deep removal of iron impurities. The fully-closed inert atmosphere conveying and packaging system used high-purity nitrogen to control the oxygen content below 0.08%, effectively preventing the product from absorbing moisture and carbonizing during storage and transportation.

[0121] From the comparison of energy consumption and environmental indicators in Table 2, the unit product comprehensive energy consumption of Example 1 is only 850 kgce / t, which is reduced by 28% compared with Comparative Example 1. This significant energy-saving effect is due to the synergistic effect of multiple mechanisms. The waste heat cascade utilization technology recovers the high-temperature flue gas at the kiln tail through the plate heat exchanger, and the heat exchange efficiency reaches 75%-85%, achieving full recovery and reuse of heat energy. The organic Rankine cycle power generation system utilizes medium-high temperature waste heat for power generation, with a power generation power of 65 kW, converting waste heat into electrical energy to realize value-added utilization of energy. The intelligent control system optimizes the fuel supply and air flow through machine learning algorithms, avoiding energy waste in traditional control methods, and reducing fuel consumption by 12%. The sound wave mass transfer enhancement technology shortens the calcination reaction time by 20%-30%, directly reducing heating time and fuel consumption. Example 1 achieves a CO2 recovery utilization rate of 15%, which is due to the application of CO2 capture and resource utilization technology. A 30wt% ethanolamine solution is used to contact the purified flue gas countercurrently in the packed absorption tower, with a CO2 absorption efficiency of 85%-92%. The recovered high-purity CO2 can be used to prepare nano calcium carbonate or synthesize methanol, realizing waste resource utilization and value-added creation. The smoke emission concentration is reduced to 8.5 mg / m 3 , and the SO2 emission concentration is reduced to 32 mg / m 3 . The significant improvement in environmental indicators is due to the application of a multi-stage flue gas purification treatment system, including the comprehensive effect of three-stage series heat exchanger cooling, cyclone dust collector and bag dust collector combined dust removal, wet desulfurization tower desulfurization, etc.

[0122] From the comparison of production efficiency indicators in Table 3, it can be found that the calcination reaction time of Example 1 is only 42 minutes, which is shortened by 77% compared with the traditional shaft kiln process of 180 minutes. This significant shortening of reaction time is mainly due to the activation of more reaction sites by plasma pretreatment technology, the promotion of mass and heat transfer process by sound wave mass transfer enhancement technology, and the creation of optimal reaction conditions by precise temperature and atmosphere control. The significant shortening of reaction time not only improves production efficiency, but also reduces energy consumption and equipment wear and tear, resulting in comprehensive benefits. The equipment comprehensive operation rate of Example 1 reaches 96.8%, and the raw material utilization rate reaches 96.5%. These excellent indicators reflect the high integration and intelligent level of the process system. The distributed sensor network monitors 90 key parameters in real time, the deep neural network model predicts and optimizes the process parameters, and the PID control algorithm realizes precise automatic adjustment. This intelligent control system significantly improves the stability and reliability of the system, reducing unplanned downtime and raw material waste.

[0123] From the comparison of economic benefit indicators in Table 4, it can be seen that Example 1 brings additional annual waste heat power generation income and CO2 resource utilization income, which is not available in Comparative Example 1. At the same time, Example 1 realizes resource comprehensive utilization and waste resource utilization.

[0124] Calcium oxide purity is one of the most important indicators to measure the quality of lime products, reflecting the degree of complete decomposition of calcium carbonate into calcium oxide and the amount of impurities in the product. From Figure 1 It can be seen that the calcium oxide purity of Example 1 reaches 98.92%, which is increased by 4.07 percentage points compared with 94.85% of Comparative Example 1, increased by 1.27 percentage points compared with 97.65% of Comparative Example 2, and increased by 0.77 percentage points compared with 98.15% of Comparative Example 3, indicating that the advanced technologies such as plasma surface pretreatment, multi-stage atmosphere control calcination, and sound wave mass transfer enhancement used in Example 1 have significant effects on improving product purity.

[0125] The activity index reflects the reaction rate and degree of calcium oxide reacting with water to generate calcium hydroxide, and is a key parameter for evaluating the reaction activity of lime products. From Figure 2 The comparison results can clearly see that the activity of Example 1 reaches 385 mL, which is significantly higher than 245 mL of Comparative Example 1, 320 mL of Comparative Example 2, and 358 mL of Comparative Example 3. The activity of Example 1 is increased by 140 mL compared with Comparative Example 1, with an increase of 57.1%, indicating that the plasma surface pretreatment technology activates more reaction sites, and the sound wave mass transfer enhancement technology improves the mass transfer conditions inside the particles.

[0126] The unit product comprehensive energy consumption is a core indicator for evaluating the energy utilization efficiency of the production process, from Figure 3 It can be seen that the unit product comprehensive energy consumption of Example 1 is only 850 kgce / t, which is reduced by 28% compared with 1180 kgce / t of Comparative Example 1, reduced by 19% compared with 1050 kgce / t of Comparative Example 2, and reduced by 8% compared with 920 kgce / t of Comparative Example 3. The main reasons for the significant reduction of energy consumption of Example 1 include the waste heat cascade utilization technology to improve energy utilization efficiency, the intelligent control system to realize accurate control of fuel supply, the organic Rankine cycle power generation system to recover high-temperature flue gas waste heat, and the sound wave mass transfer enhancement technology to shorten the reaction time and reduce the energy consumption.

[0127] The environmental emission index comparison includes CO2 emission, smoke emission concentration, SO2 emission concentration, and emission reduction rate analysis relative to Example 1. From Figure 4 The subgraphs can be seen that Example 1 performs best in all environmental indicators, with CO2 emission of 1.65 tCO2 / t product and 15% recovery and utilization, smoke emission concentration of only 8.5 mg / m 3 , SO2 emission concentration of only 32 mg / m 3 , which are much better than Comparative Example 1, Comparative Example 2 and Comparative Example 3. Example 1 adopts CO2 capture and resource utilization technology, multi-stage flue gas purification treatment system, and precise combustion control to reduce the generation of pollutants.

[0128] The production efficiency index comparison includes three key efficiency parameters: calcination reaction time, product quality standard deviation, and equipment comprehensive operation rate. Figure 5 It can be seen that the calcination reaction time of Example 1 is only 42 minutes, which is shortened by 77% compared with Comparative Example 1 of 180 minutes, shortened by 53% compared with Comparative Example 2 of 90 minutes, and shortened by 44% compared with Comparative Example 3 of 75 minutes. The product quality standard deviation of Example 1 is only ± 2.8%, which is significantly better than other comparative examples. The equipment comprehensive operation rate of Example 1 reaches 96.8%, which is higher than all comparative examples.

[0129] Figure 6 is a product quality stability comparison, through the time series data of calcium oxide purity in 30 days of continuous production. The time series data is obtained by daily timed sampling analysis, reflecting the long-term stability and quality control level of the production process. Figure 6 It can be seen that the calcium oxide purity of Example 1 remains highly stable within 30 days, with a mean value of 98.92% and a standard deviation of only ± 0.3% or so, while the quality fluctuations of Comparative Example 1, Comparative Example 2 and Comparative Example 3 are greater. The excellent quality stability of Example 1 is mainly due to the precise adjustment of the intelligent control system, the stability of multi-stage atmosphere control, and the continuous effect of the sound wave mass transfer enhancement technology.

[0130] In summary, the high-purity lime manufacturing process adopted by Example 1 is significantly superior to Comparative Example 1, Comparative Example 2 and Comparative Example 3 in terms of product quality, production efficiency, environmental performance and economic benefits. In terms of product quality, the calcium oxide purity and activity of Example 1 both reach the highest level, the impurity content is best controlled, and the quality stability is best. In terms of production efficiency, the calcination reaction time of Example 1 is the shortest, the equipment operation rate is the highest, and the production process is the most stable. In terms of environmental performance, the energy consumption of Example 1 is the lowest, and all emission indicators are the best, and CO2 capture and resource utilization are achieved. In terms of economic benefits, the raw material utilization rate of Example 1 is the highest, the production cost is the lowest, and the comprehensive economic benefits are the best; it shows that the organic integration and synergistic optimization of the plasma surface pretreatment, multi-stage gradient atmosphere calcination, sound wave mass transfer enhancement, intelligent control optimization, waste heat comprehensive utilization, CO2 capture and resource utilization and other technologies adopted by the present application produce significant comprehensive effect, and realize the revolutionary improvement and upgrading of traditional lime production process.

[0131] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. Process for the production of high-purity lime, characterized in that, The method comprises the following steps: S1, raw material pretreatment; limestone raw material is uniformly fed through a vibrating feeder, particles with a particle size of 5-20 mm are screened out, and ferromagnetic impurities are removed through a magnetic separation device to realize particle size homogenization and impurity purification of the raw material; S2, plasma surface pretreatment; the treated limestone particles are subjected to surface treatment by using low-temperature atmospheric pressure plasma to remove surface organic contaminants and oxide layers; S3, staged atmosphere calcination; the limestone particles are sequentially subjected to gradient temperature calcination through a preheating section, a decarburization section, a primary calcination section and a deep calcination section, the temperatures of the sections are controlled at 400-600 DEG C, 600-900 DEG C, 900-1100 DEG C and 1100-1250 DEG C respectively, the primary calcination section adopts a weak reducing atmosphere, and the deep calcination section adopts an oxidizing atmosphere; S4, sound wave reinforced mass transfer; during the calcination process, secondary sound waves and ultrasonic waves are applied simultaneously to promote the diffusion of CO2 gas in the particles and the stripping of surface reaction products through the mechanical vibration and cavitation effect of the sound waves; S5, heat energy comprehensive utilization and intelligent control; distributed sensor networks are used to collect the temperature, pressure and gas composition process parameters in the calcination process in real time, a process parameter optimization model is established, and the fuel supply amount and air supply amount are adjusted; meanwhile, the high-temperature waste heat generated in the calcination process is recycled; S6, rapid cooling; nano-fluid spraying and forced air cooling are combined to rapidly cool the high-temperature calcium oxide; S7, flue gas treatment; the calcination flue gas is subjected to multi-stage cooling and purification treatment, CO2 in the flue gas is recovered, and the flue gas is discharged in compliance with the standard and the CO2 is recycled; S8, product packaging; the calcium oxide is indirectly cooled to room temperature under the protection of an inert atmosphere, dry nitrogen is filled for sealing and packaging.

2. The process according to claim 1, characterized in that, The step S1 comprises: S11, vibration feeding and pre-screening; electromagnetic vibration feeders with a vibration frequency of 15-25 Hz are used for continuous feeding, the feeding speed is controlled at 2-5 t / h, and fine powder with a particle size less than 3 mm is removed for preliminary screening to avoid material agglomeration and blockage; S12, multi-stage particle size accurate screening; three layers of vibrating screens are used for grading, the first layer of screen hole is 20 mm to screen out oversized particles, the second layer of screen hole is 5 mm to screen out small particles, and the third layer of screen hole is used to ensure that the 5-20 mm particles pass through and are subjected to quality grading, oversized particles are returned after being crushed, and undersized particles are used as fillers; S13, two-stage magnetic separation and deep purification; first, weak magnetic impurities are removed through a low-intensity magnetic separator with a magnetic field strength of 800-1200 Gauss, and then strong magnetic impurities are removed through a high-intensity magnetic separator with a magnetic field strength of 8000-12000 Gauss, the magnetic separation speed is controlled at 0.5-1.0 m / s, and high-purity limestone raw material is obtained.

3. The process of claim 1, wherein, The step S2 comprises: S21, plasma field establishment; a dielectric barrier discharge device with a power of 1.5-2.0 kW and a working voltage of 3-5 kV is used to generate low-temperature atmospheric pressure plasma, the discharge frequency is 20-50 kHz, and a uniform plasma field is formed in the treatment chamber; S22, particle surface micro-modification; limestone particles stay in the plasma field for 30-60 seconds to remove surface organic contaminants and oxidation layers; at the same time, plasma bombardment on the limestone surface produces point defects, line defects and lattice defects to form high-activity reaction sites.

4. The process of claim 1, wherein, The step S3 comprises: S31, waste heat preheating; in the 400-600℃ preheating section, the high-temperature flue gas of 1000-1200℃ at the kiln tail is used to preheat the material through the plate heat exchanger, and the material temperature is uniformly raised to 580-620℃, realizing the thermal energy cascade utilization; S32, oxygen-enriched decarburization pretreatment; oxygen-enriched gas with oxygen content of 25%-30% is introduced into the decarburization preheating section at 600-900℃, and the flow rate is controlled at 100-150 Nm 3 / h, to promote the beginning of the calcium carbonate decomposition reaction; S33, weak reduction primary calcination; in the 900-1100℃ primary calcination section, a weak reduction atmosphere with CO concentration of 1%-3% is used to inhibit the further oxidation of Fe2O3 and Al2O3 impurities, and a preliminary calcium oxide product is obtained to ensure the high purity characteristics of the product; S34, high-temperature oxidation atmosphere deep calcination; in the 1100-1250℃ deep calcination section, an oxidation atmosphere with oxygen concentration of 18%-20% is used, and the residence time is controlled at 45-60 minutes to completely decompose the residual calcium carbonate and obtain the calcium oxide product.

5. The process of claim 4, wherein, The step S4 comprises: S41, insonation mass transfer promotion; in the primary calcination and deep calcination stages, the insonation wave with frequency of 35-45Hz and sound pressure level of 80-100dB is applied, and the electromagnetic excitation method is used for the sound wave generator to make the sound wave penetrate to the inside of the reactant material particles, thereby promoting the diffusion and mass transfer of CO2 gas in the particles and accelerating the exclusion of reaction gas; S42, ultrasonic surface activation; at the same time, ultrasonic waves with a frequency of 18-22 kHz and a sound power density of 2-5 W / cm 2 are applied to produce cavitation effect and microjet on the surface of the reaction material and accelerate the stripping of the surface reaction product CaO.

6. The process of claim 1, wherein, The step S5 comprises: S51, real-time data acquisition monitoring; through the temperature sensor, pressure sensor, gas composition analyzer and flow sensor distributed in each section of the calcination kiln, the temperature , , , , pressure , , , , oxygen concentration , carbon dioxide concentration , fuel flow , air flow key parameters, wherein is the preheating section temperature; is the decarburization section temperature; is the primary calcination section temperature; is the deep calcination section temperature; is the preheating section pressure; is the decarburization section pressure; is the primary calcination section pressure; is the deep calcination section pressure; is the oxygen concentration; is the carbon dioxide concentration; is the fuel flow; is the air flow, a real-time database is established; S52, data preprocessing and feature extraction; the collected original data is subjected to filtering and denoising treatment, and Kalman filtering algorithm is used to eliminate measurement noise; S53, machine learning model training and updating; a deep neural network algorithm is used to establish a process parameter optimization model, and principal component analysis method is used for feature selection; S54, optimal parameter calculation and prediction; with product purity , activity and energy consumption as multi-objective optimization functions, the objective function is established: ； wherein, is the comprehensive evaluation function; , , is the weight coefficient adjusted according to the actual process requirements, and the optimal fuel flow is calculated: ； wherein, is the optimal fuel flow rate; is the neural network mapping function; is the preheat measured temperature; is the decarbonization measured temperature; is the primary calcination measured temperature; is the deep calcination measured temperature; is the oxygen concentration; is the carbon dioxide concentration; Meanwhile, the optimal air flow is calculated: ； wherein, is the optimal air flow rate; is a neural network mapping function; S55, dynamic parameter automatic regulation; according to the optimization calculation results, the fuel supply amount, air supply amount and waste heat distribution ratio are automatically adjusted by the PID control algorithm, and the fuel control output is obtained; S56, waste heat comprehensive recovery and utilization; the high-temperature flue gas is used to generate electricity through the organic Rankine ORC system circulating power generation device, and the medium and low temperature waste heat is used to prepare process hot water, realizing the cascade utilization and comprehensive recovery of energy.

7. The process of claim 1, wherein, The step S6 comprises: S61, nanofluid rapid cooling; Al2O3 and H2O nanofluid are used as the cooling medium, the nanometer particle concentration is 1%-3%vol, the nanometer particles are prepared by ultrasonic dispersion technology and a stabilizer is added to maintain stability, the high-temperature calcium oxide at 1150-1250℃ is sprayed and cooled through a high-pressure nozzle at a pressure of 3-5MPa, the spraying time is 30-45 seconds, the material temperature is rapidly reduced to 600-700℃, the first stage rapid cooling is realized, and the excessive sintering of calcium oxide under high temperature conditions is avoided; S62, circulating forced air cooling; immediately start the circulating cooling air system after nano-fluid spraying cooling, control the air speed at 15-20 m / s and the air temperature at 30-50 ℃, and forced air cooling for 90-120 seconds to further reduce the material temperature to 150-200 ℃, complete the second stage cooling process, and maintain the microstructure and high activity characteristics of the calcium oxide particles; S63, inert atmosphere protection cooling; through the combined cooling effect of the first two steps, rapid cooling is realized within a total cooling time of 2-3 minutes, while N2 or Ar inert gas protection is passed, and the gas flow is controlled at 50-80 Nm 3 / h, to prevent the reaction of calcium oxide with CO2 and H2O in the air.

8. The process of claim 1, wherein, The step S7 comprises: S71, flue gas cooling and purification pretreatment; the 1000-1200 ℃ high-temperature flue gas generated in the calcination process is sequentially cooled to 800 ℃, 400 ℃ and 200-250 ℃ through a three-stage series heat exchanger; then the dust in the flue gas is removed through a cyclone dust collector and a bag dust collector, and then SO2 is removed through a desulfurization tower; finally, the temperature is cooled to 40-50 ℃; S72, high-efficiency CO2 separation and capture; 30wt% MEA ethanolamine solution is used to contact with the purified flue gas in countercurrent in a packed absorption tower, the operation pressure of the absorption tower is 0.1-0.15 MPa, the temperature is 40-60 ℃, the circulation amount of the MEA solution is 500-800 L / h, the CO2-rich solution is regenerated at 120-130 ℃ through a desorption tower with a desorption pressure of 0.15-0.2 MPa, and high-efficiency separation and recovery of CO2 are realized; S73, CO2 high-value resource utilization; the captured CO2 is pressurized to 5 MPa through a compressor and then transported to the downstream to react with the prepared CaO in a stirring reaction kettle to prepare nano calcium carbonate, or transported to a methanol synthesis device to synthesize methanol with H2 under the action of a Cu-Zn-Al catalyst, and CO2 emission reduction and resource utilization are realized.

9. The process of claim 1, wherein, The step S8 comprises: S81, full-closed inert atmosphere transportation; the calcium oxide product with a temperature of 150-200 ℃ after quenching is transported through a closed screw conveyor, and N2 inert gas with a purity of ≥99.5% is filled in the conveying pipeline; S82, indirect cooling to room temperature; the calcium oxide in transportation is continuously cooled to reduce the product temperature to within +5 ℃ of the ambient temperature; S83, automatic quantitative sealing and packaging; the calcium oxide is accurately weighed and packaged through an electronic scale, and dry N2 gas is filled after packaging to make the oxygen content in the bag <0.1%.

10. A high-purity lime manufacturing system for carrying out the process according to any one of claims 1 to 9, characterized in that, The system comprises: A raw material pretreatment unit arranged at the feeding end of the system, which comprises a vibrating feeder, a three-layer vibrating screen separator and a double-stage magnetic separation device connected in series, and realizes uniform feeding, accurate screening and deep iron removal and purification of the limestone raw material; A plasma surface pretreatment unit connected with the outlet of the raw material pretreatment unit through a closed conveying pipeline, which comprises a dielectric barrier discharge plasma generator, a treatment chamber and a material conveying device, and performs surface activation treatment on the limestone particles to remove surface organic contaminants and oxide layers and form high-activity reaction sites; A plasma surface pretreatment unit connected with the outlet of the raw material pretreatment unit through a closed conveying pipeline, which comprises a dielectric barrier discharge plasma generator, a treatment chamber and a material conveying device, and performs surface activation treatment on the limestone particles to remove surface organic contaminants and oxide layers and form high-activity reaction sites; The multi-section gradient atmosphere calcination kiln is connected with the outlet of the plasma surface pretreatment unit through a feeding port, has a multi-section kiln body structure, and comprises, from top to bottom, a preheating section, a decarburization section, a primary calcination section, and a deep calcination section, so as to realize gradient temperature calcination and complete decomposition of limestone, wherein the preheating section is indirectly preheated by high-temperature flue gas at the kiln tail, the decarburization section is supplied with oxygen-rich gas to promote preliminary decomposition of calcium carbonate, the primary calcination section adopts a weak reducing atmosphere to inhibit oxidation of impurities, and the deep calcination section adopts an oxidizing atmosphere to realize complete decomposition of calcium carbonate; The sound wave mass transfer strengthening system is installed in the primary calcination section and the deep calcination section of the multi-section gradient atmosphere calcination kiln, comprises a infrasound generator and an ultrasonic generator, promotes diffusion of CO2 gas in the particles through infrasound, and accelerates stripping of surface reaction products through cavitation effect of ultrasonic waves; The heat energy comprehensive utilization and intelligent control system is connected with the multi-section gradient atmosphere calcination kiln through signal cables and control pipelines, comprises a distributed sensor network, a data processing unit, a machine learning optimization module, a control execution unit, and a waste heat recovery device, the distributed sensor network collects temperature, pressure, gas composition, and flow parameters of each section in real time and transmits them to the data processing unit, the machine learning optimization module establishes a process parameter optimization model to calculate optimal fuel supply and air flow, the control execution unit automatically adjusts relevant parameters according to the optimization results, and the waste heat recovery device generates electricity and produces hot water by using high-temperature flue gas; The rapid cooling unit is connected with the material outlet of the multi-section gradient atmosphere calcination kiln, comprises a nanofluid spraying system and a forced air cooling system, the nanofluid spraying system sprays nanofluid to cool high-temperature calcium oxide, and the forced air cooling system performs second-stage cooling, so as to realize rapid cooling and maintain product activity; The flue gas treatment unit is connected with the flue gas outlet of the multi-section gradient atmosphere calcination kiln through a flue gas pipeline, comprises multi-stage heat exchangers, a dust removal and purification device, a CO2 absorption and separation device, and a CO2 utilization device, the multi-stage heat exchangers cool high-temperature flue gas, the dust removal and purification device removes dust and SO2 in the flue gas, the CO2 absorption and separation device captures CO2 in the flue gas by using ethanolamine solution, and the CO2 utilization device uses the recovered CO2 to prepare nanometer calcium carbonate or synthesize methanol; The finished product packaging unit is connected with the rapid cooling unit through a sealed pipeline, comprises an inert atmosphere conveying system, an indirect cooling device, and an automatic packaging device, the inert atmosphere conveying system conveys calcium oxide products in a sealed environment filled with inert gas, the indirect cooling device cools the products to room temperature, and the automatic packaging device quantitatively packages the calcium oxide and fills it with dry nitrogen gas for sealing.

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