High-activity desulfurizing agent, preparation method and intelligent precise quantity-controlled feeding method thereof

Abstract

The invention discloses a high-activity desulfurizing agent as well as a preparation method and an intelligent precise quantity-controlled feeding method thereof, and relates to the field of industrial flue gas desulfurization. The desulfurizing agent comprises the following components in parts by weight: 85-90 parts of calcium hydroxide; 0.5 to 1.0 part of a pore forming agent; 1.0 to 1.5 parts of a nano catalyst; 5-10 parts of nano sodium bicarbonate; 3-5 parts of calcium oxide; calcium hydroxide, a pore-forming agent and a nano-catalyst are mixed, calcined and activated to generate modified calcium hydroxide powder which has abundant void structures, the specific surface area is larger than or equal to 50 m / g, and the surface of the modified calcium hydroxide powder is uniformly loaded with the nano-catalyst, and the surface of the modified calcium hydroxide powder is uniformly coated with nano sodium bicarbonate. The calcium oxide is uniformly mixed with the modified calcium hydroxide powder coated with the nano sodium bicarbonate on the surface in a powder form. According to the intelligent precise quantity-controlled feeding method, the feed-forward-feedback composite control model is constructed, working condition parameters are monitored in real time, the spraying quantity of the desulfurizing agent is dynamically calculated and precisely controlled, and the stable standard reaching of the desulfurization efficiency and the optimization of the consumption of the desulfurizing agent are realized.

Description

Technical Field

[0001] This invention relates to the field of industrial flue gas desulfurization technology, specifically to a highly active desulfurizing agent, its preparation method, and its intelligent and precise dosage control method. Background Technology

[0002] Sulfur dioxide (SO2) in flue gas is one of the major air pollutants, with widespread sources such as coal-fired boilers, steel sintering, and cement kilns. Flue gas desulfurization is a key technology for controlling industrial SO2 emissions. Currently, industrial desulfurization technologies are mainly divided into wet, semi-dry, and dry methods. Among them, dry desulfurization technology is widely used in small and medium-sized units and some industrial sectors due to its advantages such as simple system structure, small footprint, no wastewater generation, resource utilization of by-products, and relatively low investment.

[0003] Currently, there are two main types of desulfurizing agents used in dry desulfurization technology: sodium-based and calcium-based. Sodium-based desulfurizing agents primarily use sodium bicarbonate as their active ingredient. By injecting sodium bicarbonate powder into high-temperature flue gas, it rapidly decomposes into sodium carbonate, carbon dioxide, and water. Subsequently, the sodium carbonate reacts with sulfur dioxide in the flue gas to produce sodium sulfite and sodium sulfate, thus achieving desulfurization. Sodium-based desulfurizing agents have high reactivity, are easy to grind, and have good powder flowability. However, traditional sodium-based desulfurizing agents face significant technical bottlenecks in practical applications: 1. Limited desulfurization efficiency: Traditional sodium bicarbonate decomposes at a relatively high temperature (approximately 150-200℃). Under conditions of large flue gas temperature fluctuations or below 150℃, decomposition is incomplete, leading to insufficient utilization of the active component. Desulfurization efficiency typically struggles to exceed 90%, failing to meet the increasingly stringent ultra-low emission standards (SO2 emission concentration ≤10mg / Nm³) in some regions; 2. Weak resistance to impurity interference: Acidic impurities such as hydrogen chloride and hydrogen fluoride often present in flue gas preferentially react with sodium bicarbonate. The consumption of large amounts of active ingredients further reduces the selective adsorption and reaction capacity for sulfur dioxide, leading to a surge in desulfurizer consumption; 3. High cost: Raw material prices are expensive, and traditional processes require grinding sodium bicarbonate into 200-300 mesh fine powder to increase the reaction contact area, but ultrafine grinding consumes a lot of energy and causes significant equipment wear, increasing production and application costs; 4. Poor temperature stability: When the flue gas temperature is above 250℃, traditional sodium bicarbonate-based desulfurizers are prone to excessive decomposition, and the generated sodium carbonate is easily sintered into lumps, reducing the specific surface area and causing a sharp decline in subsequent reaction activity. Compared with sodium-based desulfurizers, calcium-based desulfurizers have cheaper and more readily available raw materials, lower operating costs, and stronger adaptability, and can treat high-concentration sulfur dioxide flue gas, such as sintered flue gas with SO2>2000mg / Nm³. However, their disadvantages are also obvious: their specific surface area is low, their pore structure is underdeveloped, and they have fewer active sites in contact with SO2. Under low-temperature conditions below 140℃, the reaction kinetics are slow, and the desulfurization efficiency drops sharply.

[0004] To overcome the shortcomings of single desulfurizing agents, existing technologies have attempted to simply physically mix sodium-based and calcium-based desulfurizing agents. However, practical experience has shown that this simple mixing cannot achieve a synergistic effect between the components; it only results in a linear additive effect of performance and fails to fundamentally solve the core problems of high sodium salt consumption and insufficient calcium-based activity. Although there have been some attempts to improve the activity of calcium-based desulfurizing agents through physical mixing or simple chemical modification, the effects are limited and cannot fundamentally solve the core problems of "deactivation" and low utilization rate in low-temperature regions.

[0005] In addition, a particularly prominent problem with the two traditional desulfurizing agents mentioned above is their poor adaptability to operating conditions. When operating parameters such as flue gas flow rate, temperature, and sulfur dioxide concentration fluctuate significantly, the desulfurization effect is significantly affected. For example, when changes in power plant load cause large fluctuations in flue gas flow rate, traditional desulfurizing agents cannot adjust their reaction rate in time, resulting in unstable desulfurization efficiency and occasional exceedances of emission standards. To solve this problem, the following feeding control methods are typically adopted:

[0006] 1. Fixed-ratio injection method: A fixed SDS injection rate is set based on the boiler's maximum load and the design inlet SO2 concentration. This method is the simplest, but it cannot adapt to changes in actual operating conditions.

[0007] 2. Simple feedforward control method: The amount of desulfurizing agent added is linearly adjusted proportionally based solely on changes in either the flue gas flow rate or the inlet SO2 concentration. For example, if the flow rate increases by 10%, the amount of desulfurizing agent added also increases by 10%.

[0008] 3. Outlet Concentration Feedback Control Method: This method involves periodically monitoring the outlet SO2 concentration. When the concentration exceeds the standard, a fixed feed rate is manually or automatically increased; when the concentration is significantly below the standard, the feed rate is reduced. This method has a slow response time and is prone to causing fluctuations in the outlet concentration.

[0009] The above three methods have the following significant drawbacks:

[0010] 1. Low control precision and unstable desulfurization efficiency: Fixed or simple linear control cannot cope with the complex coupled changes of multiple parameters such as flue gas flow, SO2 concentration, temperature, and humidity, resulting in frequent fluctuations in outlet SO2 concentration and difficulty in achieving stable standards.

[0011] 2. Significant waste of desulfurizing agent and high operating costs: To ensure compliance under any operating conditions, operators often tend to over-inject desulfurizing agent, resulting in huge waste of the agent. This problem is particularly prominent when the flue gas load decreases.

[0012] 3. Poor system adaptability: It cannot quickly respond to fluctuations in boiler load (such as start-up, shutdown, and peak shaving), resulting in poor desulfurization effect or waste of reagents during the transition phase.

[0013] 4. It is easy to generate secondary pollution: Excessive unreacted desulfurizing agent or its products will be discharged with the flue gas, increasing the concentration of flue gas emissions and even affecting the normal operation of downstream equipment (such as bag filters). Summary of the Invention

[0014] To address the shortcomings of the aforementioned technologies, this invention provides a highly active desulfurizing agent, its preparation method, and its intelligent and precise dosage control method.

[0015] The technical solution adopted by the present invention to achieve the above-mentioned technical effects is as follows:

[0016] A highly active desulfurizing agent, comprising the following components by weight:

[0017] 85-90 parts of calcium hydroxide;

[0018] 0.5–1.0 parts of pore-forming agent;

[0019] 1.0–1.5 parts of nanocatalyst;

[0020] 5-10 parts of nano sodium bicarbonate;

[0021] 3-5 parts calcium oxide;

[0022] In this process, the calcium hydroxide, pore-forming agent, and nano-catalyst are mixed, calcined, and activated to generate modified calcium hydroxide powder with a rich pore structure, a specific surface area ≥50 m² / g, and a uniformly loaded nano-catalyst on the surface. The nano-sodium bicarbonate is uniformly coated on the surface of the modified calcium hydroxide powder, and the calcium oxide is uniformly mixed with the modified calcium hydroxide powder coated with nano-sodium bicarbonate in powder form.

[0023] Preferably, in the above-mentioned highly active desulfurizing agent, the particle size of the calcium hydroxide is 30-50 μm, and the particle size of the calcium oxide is 10-30 μm.

[0024] Preferably, in the above-mentioned highly active desulfurizing agent, the pore-forming agent is polyethylene glycol or polyvinyl alcohol, or a combination of the two in any proportion.

[0025] Preferably, in the above-mentioned highly active desulfurizing agent, the nanocatalyst is manganese dioxide.

[0026] Preferably, in the above-mentioned highly active desulfurizing agent, the particle size of the nano sodium bicarbonate is d90≤400nm.

[0027] A method for preparing the above-mentioned highly active desulfurizer includes the following steps:

[0028] S1. Mixing and pretreatment: Add 85-90 parts of calcium hydroxide, 0.5-1.0 parts of pore-forming agent, and 1.0-1.5 parts of nano-catalyst to a high-speed mixer and dry mix for 10-15 minutes under an inert atmosphere at 60-80°C to obtain a uniform premix.

[0029] S2. High-temperature calcination to form pores: The premix obtained in step S1 is placed in a muffle furnace or rotary kiln and heated to 600-700°C at a heating rate of 5-10°C / min and held for 1-3 hours. The pore-forming agent is decomposed and vaporized to form a microporous framework through high-temperature calcination, and the nanocatalyst is immobilized on the calcined product calcium oxide.

[0030] S3. Temperature-controlled hydration activation: The calcined calcium oxide product obtained in step S2 is quickly transferred to a hydration reactor equipped with a temperature control and stirring device. Deionized water is added at a solid-liquid ratio of 1:3 to 1:5. The mixture is stirred and hydrated at 60 to 80°C for 1 to 2 hours to allow the calcined calcium oxide product to react with water and generate highly active modified calcium hydroxide.

[0031] S4. Drying and sieving: The slurry obtained in step S3 is centrifuged or dehydrated by pressure filtration, and then dried in an oven at 100-120℃ to constant weight. Finally, modified calcium hydroxide powder with a particle size d90≤400nm is obtained by sieving.

[0032] S5. Enhanced surface activity: The modified calcium hydroxide powder obtained in step S4 is put into a fluidized bed and preheated to 70-90°C. Then, 5-10 parts of nano sodium bicarbonate are fed into the fluidized bed through airflow so that the nano sodium bicarbonate is uniformly coated on the surface of the modified calcium hydroxide powder.

[0033] S6. Enhanced effective activity: Add 3-5 parts of calcium oxide in powder form and the modified calcium hydroxide powder with nano-sodium bicarbonate coating obtained in step S5 into a high-speed mixer. Dry mix for 30-60 minutes under an inert atmosphere at 60-80°C to obtain a uniform, highly active desulfurizing agent powder.

[0034] A smart and precise dosage control method for the above-mentioned highly active desulfurizing agent includes the following steps:

[0035] S1. Real-time acquisition of flue gas state parameters at the inlet and outlet flues of the desulfurization reaction tower, wherein the flue gas state parameters include:

[0036] flue gas flow rate ,unit ;

[0037] SO2 concentration at the inlet ,unit ;

[0038] SO2 concentration at the outlet ,unit ;

[0039] flue gas temperature ,unit ;

[0040] flue gas humidity ;

[0041] S2. Feedforward model calculation to predict the theoretical consumption of desulfurizing agent. Based on the flue gas state parameters collected at the inlet flue, the theoretically required consumption of desulfurizing agent is calculated. The steps are as follows:

[0042] S21, Calculate the hourly mass flow rate of SO2 at the inlet. ,unit ,in, ;

[0043] S22. Calculate the target SO2 mass flow rate per hour. , ,in, The set target SO2 concentration at the outlet, in units ;

[0044] S23. Calculate the hourly mass flow rate of SO2 to be removed. , ;

[0045] S24. Calculate the theoretical consumption of desulfurizing agent. ,unit ,in, ;

[0046] S25. Introduce the operating condition correction coefficient to obtain the output of the feedforward model. ,in, This is a temperature correction factor. This is the humidity correction factor. This is the desulfurizer activity correction factor;

[0047] S3. Feedback model calculation and accuracy correction: Based on the output of the feedforward model, the PID controller dynamically fine-tunes the calculation according to the deviation between the measured value and the target value of the outlet SO2 concentration, forming the feedback correction amount. The steps are as follows:

[0048] S31, Calculate the deviation , ;

[0049] S32, PID controller calculates correction factor , ,in, , , These are the proportional coefficient, integral coefficient, and differential coefficient, respectively. Fluctuating around a value of 1, when the concentration of SO2 at the outlet... When it is too high, Negative, Increase, and vice versa;

[0050] Step S4, final dosage calculation and command output: The predicted value from the feedforward model and the corrected value from the feedback model are combined to obtain the final accurate desulfurizer dosage output command. The output command for desulfurizing agent dosage is converted into a frequency or speed command from a frequency converter or motor controller, which drives the feeding device to accurately feed the desulfurizing agent according to the corresponding dosage.

[0051] Step S5: Execute repeatedly. The system executes steps S1 to S4 at a high frequency of 1 to 10 seconds to form a closed-loop real-time dynamic dosage control of the desulfurizing agent.

[0052] Preferably, in the above-described intelligent and precise dosage control method for highly active desulfurizing agents, in step S25, ,in, For the optimal reaction temperature, The temperature influence coefficient was obtained through experimental calibration.

[0053] Preferably, in the above-described intelligent and precise dosage control method for highly active desulfurizing agents, in step S25, ,in, For optimal humidity, The temperature influence coefficient is determined experimentally.

[0054] Preferably, in the above-described intelligent and precise dosage control method for highly active desulfurizing agents, in step S25, ,in, This represents the percentage of the effective component in the desulfurizing agent.

[0055] The beneficial effects of this invention are as follows: Compared with sodium-based and calcium-based desulfurizers in the prior art, the highly active desulfurizer of this invention has the following significant technical advantages:

[0056] 1. Rapid start-up and deep purification: Calcium oxide can preferentially react with hydrogen chloride and hydrogen fluoride in flue gas, reducing the consumption of the core active components of the desulfurizer and improving the selectivity for SO2. The nano sodium bicarbonate uniformly coated on the surface of modified calcium hydroxide powder can react with SO2 in flue gas instantly, achieving a "second-level" response and ensuring that the desulfurization efficiency reaches the standard quickly. Then, the modified calcium hydroxide continues to react with SO2, ensuring the continuity and depth of desulfurization and improving the utilization rate of calcium.

[0057] 2. Excellent low-temperature desulfurization performance: The rich microporous network constructed by the pore-forming agent greatly increases the specific surface area of ​​the desulfurizer, providing a large number of adsorption channels and reaction sites for SO2. Combined with the catalytic oxidation effect of the nano-catalyst, the activation energy of the reaction is significantly reduced, allowing the desulfurizer to maintain a high efficiency of over 97% within a low-temperature window of 120-180℃.

[0058] 3. Extremely high calcium utilization rate: The microporous structure allows the reaction to penetrate from the particle surface to the interior, avoiding the internal deactivation problem caused by "outer shell densification". The synergistic effect of the catalyst also accelerates the reaction process, making the chemical utilization rate of calcium more than 40% higher than that of ordinary calcium hydroxide, and significantly reducing the consumption of desulfurizing agent under the same desulfurization effect;

[0059] 4. Significant economic and environmental benefits: Only a small amount of nano-sodium bicarbonate is needed to start and maintain a highly efficient reaction. Compared with pure sodium-based desulfurizers, sodium salt consumption is reduced by more than 60%, significantly saving operating costs. Using inexpensive calcium hydroxide as the main raw material, the overall operating cost is far lower than that of sodium bicarbonate. Due to the high calcium utilization rate, solid waste production is reduced. More importantly, the byproduct is almost pure calcium sulfate, which can be seamlessly integrated into the cement, gypsum board, and other building materials industries, achieving true "waste-to-treasure" and a circular economy.

[0060] 5. Good product strength and flowability: After high-temperature calcination and hydration recrystallization, the mechanical strength of the desulfurizer particles is improved, making them less prone to pulverization during transportation and spraying, thus ensuring good flowability and dispersibility.

[0061] Moreover, the intelligent and precise dosage control method of this invention can significantly save desulfurizing agent, avoiding waste of agents under low load or low sulfur conditions. It is estimated that it can save 15%-30% of desulfurizing agent usage, resulting in significant economic benefits. Secondly, it can automatically adapt to changes in various factors such as boiler load and fuel sulfur content without manual intervention, greatly reducing the labor intensity and risk of misoperation for operators. Thirdly, it can precisely control and avoid excessive desulfurizing agent injection, reducing the generation of unreacted dust, which helps to reduce the total amount of flue gas emissions, making the entire desulfurization system more environmentally friendly and efficient. Detailed Implementation

[0062] To provide a further understanding of the present invention, the invention will be further described below with reference to specific embodiments:

[0063] Example 1:

[0064] This embodiment provides a highly active desulfurizing agent, which, by weight, comprises the following components:

[0065] 90 parts of calcium hydroxide;

[0066] 0.5 parts of pore-forming agent;

[0067] 1.0 part of nanocatalyst;

[0068] Five parts of nano-sodium bicarbonate;

[0069] 3 parts calcium oxide;

[0070] In this process, the calcium hydroxide, pore-forming agent, and nano-catalyst are mixed, calcined, and activated to generate modified calcium hydroxide powder with a rich pore structure, a specific surface area ≥50 m² / g, and a uniformly loaded nano-catalyst on the surface. The nano-sodium bicarbonate is uniformly coated on the surface of the modified calcium hydroxide powder, and the calcium oxide is uniformly mixed with the modified calcium hydroxide powder coated with nano-sodium bicarbonate in powder form.

[0071] Further, in a preferred embodiment of the present invention, the particle size of calcium hydroxide is 30–50 μm, and the particle size of calcium oxide is 10–30 μm. The pore-forming agent is polyethylene glycol or polyvinyl alcohol, or a combination of the two in any proportion. The nanocatalyst is manganese dioxide with a particle size of 80–100 nm, and the nano-sodium bicarbonate has a particle size of d90 ≤ 400 nm.

[0072] Example 2:

[0073] This second embodiment provides a highly active desulfurizing agent, which, by weight, comprises the following components:

[0074] 87 parts of calcium hydroxide;

[0075] 0.8 parts of pore-forming agent;

[0076] 1.2 parts of nanocatalyst;

[0077] 7 parts of nano-sodium bicarbonate;

[0078] 4 parts calcium oxide;

[0079] In this process, the calcium hydroxide, pore-forming agent, and nano-catalyst are mixed, calcined, and activated to generate modified calcium hydroxide powder with a rich pore structure, a specific surface area ≥50 m² / g, and a uniformly loaded nano-catalyst on the surface. The nano-sodium bicarbonate is uniformly coated on the surface of the modified calcium hydroxide powder, and the calcium oxide is uniformly mixed with the modified calcium hydroxide powder coated with nano-sodium bicarbonate in powder form.

[0080] Further, in a preferred embodiment of the present invention, the particle size of calcium hydroxide is 30–50 μm, and the particle size of calcium oxide is 10–30 μm. The pore-forming agent is polyethylene glycol or polyvinyl alcohol, or a combination of the two in any proportion. The nanocatalyst is manganese dioxide with a particle size of 80–100 nm, and the nano-sodium bicarbonate has a particle size of d90 ≤ 400 nm.

[0081] Example 3:

[0082] This embodiment three provides a highly active desulfurizing agent, which, by weight, comprises the following components:

[0083] 85 parts of calcium hydroxide;

[0084] 1.0 part of pore-forming agent;

[0085] 1.5 parts of nanocatalyst;

[0086] 10 parts of nano sodium bicarbonate;

[0087] 5 parts calcium oxide;

[0088] In this process, the calcium hydroxide, pore-forming agent, and nano-catalyst are mixed, calcined, and activated to generate modified calcium hydroxide powder with a rich pore structure, a specific surface area ≥50 m² / g, and a uniformly loaded nano-catalyst on the surface. The nano-sodium bicarbonate is uniformly coated on the surface of the modified calcium hydroxide powder, and the calcium oxide is uniformly mixed with the modified calcium hydroxide powder coated with nano-sodium bicarbonate in powder form.

[0089] Further, in a preferred embodiment of the present invention, the particle size of calcium hydroxide is 30–50 μm, and the particle size of calcium oxide is 10–30 μm. The pore-forming agent is polyethylene glycol or polyvinyl alcohol, or a combination of the two in any proportion. The nanocatalyst is manganese dioxide with a particle size of 80–100 nm, and the nano-sodium bicarbonate has a particle size of d90 ≤ 400 nm.

[0090] Comparative Example 1:

[0091] Commercial sodium bicarbonate desulfurizer with d90=20μm was used.

[0092] Comparative Example 2:

[0093] Commercially available ordinary calcium hydroxide desulfurizer with a specific surface area of ​​45 m² / g was used.

[0094] Comparative Example 3:

[0095] Take 10 parts of sodium bicarbonate desulfurizer from Comparative Example 1 and 90 parts of calcium hydroxide desulfurizer from Comparative Example 2, and mix them physically to use as desulfurizers.

[0096] To verify the performance of the desulfurizer of this invention, performance tests were conducted under four simulated operating conditions. The test results are as follows:

[0097] Operating Condition 1: Flue gas temperature 130℃, inlet SO2 concentration 1000 HCl concentration 80 According to the theoretical consumption, the corresponding amount of desulfurizing agent is added. The performance indicators of each desulfurizing agent are shown in Table 1 below.

[0098] Table 1

[0099] Group / Project Desulfurization efficiency Activity decay rate after 24 hours of continuous operation Example 1 98.2% 3.0% Example 2 98.7% 2.83% Example 3 98.5% 2.97% Comparative Example 1 80.9% 37.5% Comparative Example 2 61.0% 47.0% Comparative Example 3 75.3% 45.8%

[0100] Operating Condition 2: Flue gas temperature 300℃, inlet SO2 concentration 1800 HCl concentration 150 According to the theoretical consumption, the corresponding amount of desulfurizing agent is added. The performance indicators of each desulfurizing agent are shown in Table 2 below.

[0101] Table 2

[0102] Group / Project Desulfurization efficiency Activity decay rate after 24 hours of continuous operation Example 1 98.0% 3.2% Example 2 98.9% 2.81% Example 3 98.3% 2.95% Comparative Example 1 65.2% 61.0% Comparative Example 2 81.6% 48.5% Comparative Example 3 78.5% 57.9%

[0103] Operating Condition 3: Flue gas temperature 180℃, inlet SO2 concentration 1500 HCl concentration 110 According to the theoretical consumption, the corresponding amount of desulfurizing agent is added. The performance indicators of each desulfurizing agent are shown in Table 3 below.

[0104] Table 3

[0105] Group / Project Desulfurization efficiency Activity decay rate after 24 hours of continuous operation Example 1 98.3% 2.51% Example 2 99.0% 2.35% Example 3 98.5% 2.49% Comparative Example 1 89.5% 28.4% Comparative Example 2 83.1% 46.5% Comparative Example 3 89.9% 35.9%

[0106] Operating Condition 4: Flue gas temperature 200℃, inlet SO2 concentration 2300 HCl concentration 180 According to the theoretical consumption, the corresponding amount of desulfurizing agent is added. The performance indicators of each desulfurizing agent are shown in Table 3 below.

[0107] Table 3

[0108] Group / Project Desulfurization efficiency Activity decay rate after 24 hours of continuous operation Example 1 97.5% 3.51% Example 2 98.6% 3.35% Example 3 98.1% 3.62% Comparative Example 1 89.7% 20.9% Comparative Example 2 45.3% 55.7% Comparative Example 3 54.9% 48.9%

[0109] The verification results from the above four operating conditions show that, under these conditions, the desulfurization efficiency of the desulfurizing agent of the present invention can reach over 98%, and after 24 hours of operation, the activity decay of the desulfurizing agent can be controlled to below 3.7%. Unlike the desulfurizing agents in the three comparative examples, which are highly sensitive to flue gas temperature, HCl concentration, and inlet SO2 concentration, the desulfurizing agent of the present invention has a wide applicable flue gas temperature range. It can maintain high desulfurization efficiency and activity at flue gas temperatures below 150°C, as well as at higher flue gas temperatures and higher inlet SO2 concentrations.

[0110] On the other hand, the present invention also proposes a method for preparing the above-mentioned highly active desulfurizer, comprising the following steps:

[0111] S1. Mixing and pretreatment: Add 85-90 parts of calcium hydroxide, 0.5-1.0 parts of pore-forming agent, and 1.0-1.5 parts of nano-catalyst to a high-speed mixer and dry mix for 10-15 minutes under an inert atmosphere at 60-80°C to obtain a uniform premix.

[0112] S2. High-temperature calcination to form pores: The premix obtained in step S1 is placed in a muffle furnace or rotary kiln and heated to 600-700°C at a heating rate of 5-10°C / min and held for 1-3 hours. The pore-forming agent is decomposed and vaporized to form a microporous framework through high-temperature calcination, and the nanocatalyst is immobilized on the calcined product calcium oxide.

[0113] S3. Temperature-controlled hydration activation: The calcined calcium oxide product obtained in step S2 is quickly transferred to a hydration reactor equipped with a temperature control and stirring device. Deionized water is added at a solid-liquid ratio of 1:3 to 1:5. The mixture is stirred and hydrated at 60 to 80°C for 1 to 2 hours to allow the calcined calcium oxide product to react with water and generate highly active modified calcium hydroxide.

[0114] S4. Drying and sieving: The slurry obtained in step S3 is centrifuged or dehydrated by pressure filtration, and then dried in an oven at 100-120℃ to constant weight. Finally, modified calcium hydroxide powder with a particle size d90≤400nm is obtained by sieving.

[0115] S5. Enhanced surface activity: The modified calcium hydroxide powder obtained in step S4 is put into a fluidized bed and preheated to 70-90°C. Then, 5-10 parts of nano sodium bicarbonate are fed into the fluidized bed through airflow so that the nano sodium bicarbonate is uniformly coated on the surface of the modified calcium hydroxide powder.

[0116] S6. Enhanced effective activity: Add 3-5 parts of calcium oxide in powder form and the modified calcium hydroxide powder with nano-sodium bicarbonate coating obtained in step S5 into a high-speed mixer. Dry mix for 30-60 minutes under an inert atmosphere at 60-80°C to obtain a uniform, highly active desulfurizing agent powder.

[0117] Based on the practical verification of the above different embodiments and comparative examples, it can be seen that the highly active desulfurizer of the present invention has the following significant technical advantages compared with the sodium-based and calcium-based desulfurizers in the prior art:

[0118] 1. Rapid start-up and deep purification: Calcium oxide can preferentially react with hydrogen chloride and hydrogen fluoride in flue gas, reducing the consumption of the core active components of the desulfurizer and improving the selectivity for SO2. The nano sodium bicarbonate uniformly coated on the surface of modified calcium hydroxide powder can react with SO2 in flue gas instantly, achieving a "second-level" response and ensuring that the desulfurization efficiency reaches the standard quickly. Then, the modified calcium hydroxide continues to react with SO2, ensuring the continuity and depth of desulfurization and improving the utilization rate of calcium.

[0119] 2. Excellent low-temperature desulfurization performance: The rich microporous network constructed by the pore-forming agent greatly increases the specific surface area of ​​the desulfurizer, providing a large number of adsorption channels and reaction sites for SO2. Combined with the catalytic oxidation effect of the nano-catalyst, the activation energy of the reaction is significantly reduced, allowing the desulfurizer to maintain a high efficiency of over 97% within a low-temperature window of 120-180℃.

[0120] 3. Extremely high calcium utilization rate: The microporous structure allows the reaction to penetrate from the particle surface to the interior, avoiding the internal deactivation problem caused by "outer shell densification". The synergistic effect of the catalyst also accelerates the reaction process, making the chemical utilization rate of calcium more than 40% higher than that of ordinary calcium hydroxide, and significantly reducing the consumption of desulfurizing agent under the same desulfurization effect;

[0121] 4. Significant economic and environmental benefits: Only a small amount of nano-sodium bicarbonate is needed to start and maintain a highly efficient reaction. Compared with pure sodium-based desulfurizers, sodium salt consumption is reduced by more than 60%, significantly saving operating costs. Using inexpensive calcium hydroxide as the main raw material, the overall operating cost is far lower than that of sodium bicarbonate. Due to the high calcium utilization rate, solid waste production is reduced. More importantly, the byproduct is almost pure calcium sulfate, which can be seamlessly integrated into the cement, gypsum board, and other building materials industries, achieving true "waste-to-treasure" and a circular economy.

[0122] 5. Good product strength and flowability: After high-temperature calcination and hydration recrystallization, the mechanical strength of the desulfurizer particles is improved, making them less prone to pulverization during transportation and spraying, thus ensuring good flowability and dispersibility.

[0123] On the other hand, the present invention also proposes an intelligent and precise dosage control method for the above-mentioned highly active desulfurizing agent, comprising the following steps:

[0124] S1. Real-time acquisition of flue gas state parameters at the inlet and outlet flues of the desulfurization reaction tower, wherein the flue gas state parameters include:

[0125] flue gas flow rate ,unit ;

[0126] SO2 concentration at the inlet ,unit ;

[0127] SO2 concentration at the outlet ,unit ;

[0128] flue gas temperature ,unit ;

[0129] flue gas humidity ;

[0130] S2. Feedforward model calculation to predict the theoretical consumption of desulfurizing agent. Based on the flue gas state parameters collected at the inlet flue, the theoretically required consumption of desulfurizing agent is calculated. The steps are as follows:

[0131] S21, Calculate the hourly mass flow rate of SO2 at the inlet. ,unit ,in, ;

[0132] S22. Calculate the target SO2 mass flow rate per hour. , ,in, The set target SO2 concentration at the outlet, in units ;

[0133] S23. Calculate the hourly mass flow rate of SO2 to be removed. , ;

[0134] S24. Calculate the theoretical consumption of desulfurizing agent. ,unit ,in, ;

[0135] S25. Introduce the operating condition correction coefficient to obtain the output of the feedforward model. ,in, This is a temperature correction factor. This is the humidity correction factor. This is the desulfurizer activity correction factor;

[0136] S3. Feedback model calculation and accuracy correction: Based on the output of the feedforward model, the PID controller dynamically fine-tunes the calculation according to the deviation between the measured value and the target value of the outlet SO2 concentration, forming the feedback correction amount. The steps are as follows:

[0137] S31, Calculate the deviation , ;

[0138] S32, PID controller calculates correction factor , ,in, , , These are the proportional coefficient, integral coefficient, and differential coefficient, respectively. Fluctuating around a value of 1, when the concentration of SO2 at the outlet... When it is too high, Negative, Increase, and vice versa;

[0139] Step S4, final dosage calculation and command output: The predicted value from the feedforward model and the corrected value from the feedback model are combined to obtain the final accurate desulfurizer dosage output command. The output command for desulfurizing agent dosage is converted into a frequency or speed command from a frequency converter or motor controller, which drives the feeding device to accurately feed the desulfurizing agent according to the corresponding dosage.

[0140] Step S5: Execute repeatedly. The system executes steps S1 to S4 at a high frequency of 1 to 10 seconds to form a closed-loop real-time dynamic dosage control of the desulfurizing agent.

[0141] Furthermore, in a preferred embodiment of the present invention, in step S25, ,in, The optimal reaction temperature is within the range of 140–250 °C. This is the temperature influence coefficient, obtained through experimental calibration. When... Within the optimal range, ≈1; the greater the deviation, The larger.

[0142] Furthermore, in a preferred embodiment of the present invention, in step S25, ,in, For optimal humidity, The temperature influence coefficient is determined experimentally.

[0143] Furthermore, in a preferred embodiment of the present invention, in step S25, ,in, This refers to the percentage of the effective component of the desulfurizing agent. For example, if the percentage of the effective component of the desulfurizing agent is 95%, then... ≈1.05.

[0144] The intelligent and precise dosage control method of this invention can significantly save desulfurizing agent, avoiding waste of agents under low load or low sulfur conditions. It is estimated that it can save 15%-30% of desulfurizing agent usage, resulting in significant economic benefits. Secondly, it can automatically adapt to changes in various factors such as boiler load and fuel sulfur content without manual intervention, greatly reducing the labor intensity and risk of misoperation for operators. Thirdly, it can precisely control and avoid excessive desulfurizing agent injection, reducing the generation of unreacted dust, which helps to reduce the total amount of flue gas emissions, making the entire desulfurization system more environmentally friendly and efficient.

[0145] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A high activity desulfurizer characterized by, By weight parts, including the following components: Calcium hydroxide 85-90 parts; Pore-forming agent 0.5-1.0 parts; Nano catalyst 1.0-1.5 parts; Nano sodium bicarbonate 5-10 parts; Calcium oxide 3-5 parts; The calcium hydroxide, pore-forming agent and nano catalyst are mixed, calcined and activated to form modified calcium hydroxide powder with rich void structure, specific surface area ≥ 50 m² / g and nano catalyst uniformly loaded on the surface, the nano sodium bicarbonate is uniformly coated on the surface of the modified calcium hydroxide powder, and the calcium oxide is uniformly mixed with the modified calcium hydroxide powder coated with nano sodium bicarbonate in the form of powder.

2. The high activity desulfurizer according to claim 1, characterized by The particle size of the calcium hydroxide is 30-50 μm, and the particle size of the calcium oxide is 10-30 μm.

3. The highly active desulfurizer according to claim 1, characterized by The pore-forming agent is polyethylene glycol or polyvinyl alcohol, or a combination of the two in any ratio.

4. The highly active desulfurizer according to claim 1, characterized by The nano catalyst is manganese dioxide.

5. The highly active desulfurizer according to claim 1, characterized by The particle size of the nano sodium bicarbonate is d90≤400 nm.

6. A process for the preparation of the high activity desulfurizer according to any one of claims 1 to 5, characterized in that, The following steps are included: S1, mixing pretreatment, adding 85-90 parts of calcium hydroxide, 0.5-1.0 parts of pore-forming agent and 1.0-1.5 parts of nano catalyst into a high-speed mixer, dry mixing for 10-15 min under the protection of inert atmosphere at 60-80℃, to obtain a uniform pre-mixture; S2, high-temperature calcination and pore-forming, placing the pre-mixture obtained in step S1 in a muffle furnace or a rotary kiln, heating at a rate of 5-10℃ / min to 600-700℃ and maintaining for 1-3 hours, decomposing and gasifying the pore-forming agent to form a microporous skeleton through high-temperature calcination, and immobilizing the nano catalyst on the calcined product calcium oxide; S3, temperature-controlled hydration activation, quickly transferring the calcined product calcium oxide obtained in step S2 to a hydration reactor with temperature control and stirring device, adding deionized water at a solid-liquid ratio of 1:3-1:5, stirring and hydrating at 60-80℃ for 1-2 hours, to make the calcined product calcium oxide react with water to form high-activity modified calcium hydroxide; S4, drying and screening, centrifuging or pressure filtering the slurry obtained in step S3 to remove water, then drying in an oven at 100-120℃ to constant weight, and finally screening to obtain modified calcium hydroxide powder with a particle size of d90≤400 nm; S5, surface activity enhancement, putting the modified calcium hydroxide powder obtained in step S4 into a fluidized bed, preheating to 70-90℃, then sending 5-10 parts of nano sodium bicarbonate into the fluidized bed through air flow to make the nano sodium bicarbonate uniformly coated on the surface of the modified calcium hydroxide powder; S6, effective activity enhancement, putting 3-5 parts of calcium oxide in the form of powder into the modified calcium hydroxide powder coated with nano sodium bicarbonate obtained in step S5 into a high-speed mixer, dry mixing for 30-60 min under the protection of inert atmosphere at 60-80℃, to obtain a uniform high-activity desulfurizer powder.

7. A smart precise controlled dosing method applied to the high-activity desulfurizer of any one of claims 1-5, characterized in that, The following steps are included: S1, real-time acquisition of flue gas state parameters at the inlet flue and outlet flue of the desulfurization reaction tower, the flue gas state parameters including: Flue gas flow , units ; Concentration of inlet SO2 , units ; Concentration of SO2 exported , units ; Flue gas temperature , units ; Flue gas humidity ; S2, feedforward model calculation, predict the theoretical consumption of desulfurizer, according to the flue gas state parameters collected at the inlet flue, calculate the theoretical required consumption of desulfurizer, the steps are: S21, calculate the hourly mass flow of the inlet SO2 , units wherein, ; S22, calculate target SO2 hourly mass flow , , where, is the set exit SO2 target concentration in ppm ; S23, calculate the mass flow of SO2 to be removed per hour , ; S24, calculating the theoretical consumption of the desulfurizer , units wherein, ; S25, introducing a working condition correction coefficient to obtain a feedforward model output wherein, is a temperature correction coefficient, is a humidity correction coefficient, is a desulfurizer activity correction coefficient; S3, feedback model calculation, precision correction, based on the output of the feedforward model, through the PID controller, according to the deviation between the measured value and the target value of the outlet SO2 concentration, dynamic fine tuning is carried out to form the feedback correction, the steps are: S31, calculate the deviation , ; S32, the PID controller calculates a correction factor , wherein, , , are proportional, integral and derivative coefficients, respectively, fluctuates around the value 1, when the concentration of SO2 at the outlet is too high, negative, increases, and vice versa; Step S4, final dosing amount calculation and instruction output, combining the prediction amount of the feedforward model and the correction amount of the feedback model to obtain the final accurate desulfurizer dosing amount output instruction The desulfurizer dosing amount output instruction is converted into a frequency or rotating speed instruction of a frequency converter or a motor controller, and the feeding device is driven to accurately feed the desulfurizer according to the corresponding feeding amount. Step S5, cycle execution, the system repeatedly executes steps S1 to S4 at a high frequency of every 1-10 seconds to form a closed-loop real-time dynamic dosage control of desulfurizer. 8.The intelligent precise control method of adding high-activity desulfurizer according to claim 7, characterized in that, In the step S25, wherein, is the optimum reaction temperature, is the temperature influence coefficient, which is obtained by experiment calibration. 9.The intelligent precise control method of adding high-activity desulfurizer according to claim 7, characterized in that, In the step S25, wherein, is the optimum humidity, is the temperature influence coefficient, calibrated by experiment. 10.The intelligent precise control method of adding high-activity desulfurizer according to claim 7, characterized in that, In the step S25, wherein, is the percentage of the active ingredient of the desulfurizer.

Images