A nitrogen oxide treatment agent and a preparation process thereof

Abstract

The application discloses a nitrogen oxide treatment agent and a preparation process thereof, and relates to the technical field of air pollution treatment and environmental protection. The composite alkaline component is composed of a sodium-based compound and an activator; the nitrogen-containing reducing agent is a pyrolytic nitrogen-containing organic matter; the stabilizer system is composed of a thickening agent and a chelating agent; and the solvent is deionized water. The composite alkaline component is used for providing an alkaline environment, assisting in oxidizing low-valence nitrogen oxides, and accelerating the decomposition of nitrogen oxides. x The nitrogen-containing reducing agent generates active nitrogen species under alkaline conditions, and the active nitrogen species and NO x react to generate nitrogen and water through a reduction reaction. In the application, the sodium-based compound, the activator and the pyrolytic nitrogen-containing organic matter realize the efficient removal of NO The application solves the technical problems of high treatment cost and low efficiency in current environmental pollution, and does not need to be catalyzed by an expensive catalyst.

Description

Technical Field

[0001] This invention relates to the fields of air pollution control and environmental protection technology, and in particular to a nitrogen oxide control agent and its preparation process. Background Technology

[0002] Nitrogen oxides (NO) x Nitrogen oxides (NOx) are among the major air pollutants, including NO and NO2. Their emissions cause environmental problems such as acid rain, photochemical smog, and ozone layer depletion, while also posing serious harm to the human respiratory and cardiovascular systems. Current nitrogen oxide control technologies mainly focus on emission reduction from industrial stationary sources, addressing pollution at its source. However, this approach is insufficient for controlling nitrogen oxides (NOx) already emitted into the atmosphere. x There is very little research on governance technologies.

[0003] For denitrification technologies, the most commonly used in industry are selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR). SCR has high denitrification efficiency but is complex, with expensive and easily deactivated catalysts. SNCR is simple and has low operating costs, but its denitrification efficiency is lower, making it difficult to meet stringent emission standards. For the treatment of low-concentration nitrogen oxides in the atmosphere, existing technologies mostly rely on adsorption and catalytic oxidation. However, adsorption materials require frequent regeneration and are expensive, while catalytic oxidation suffers from catalyst deactivation and limited processing capacity, hindering large-scale application. Therefore, it is crucial to develop a technology that combines safety, high efficiency, wide temperature adaptability, requires no expensive catalysts, and is suitable for both industrial flue gas treatment and low-concentration atmospheric NO treatment. x The development of effective nitrogen oxide control agents has become a pressing technical challenge for the industry. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a solution suitable for treating high-concentration NOx in industrial flue gas and low-concentration NOx in the atmospheric environment. x The nitrogen oxide treatment agent products have solved the technical problems of high treatment costs and low efficiency in the current environmental pollution control.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a nitrogen oxide control agent, comprising a composite alkaline component, a nitrogen-containing reducing agent, a stabilizer system, and a solvent;

[0008] The composite alkaline component is composed of a sodium-based compound and an activator;

[0009] The nitrogen-containing reducing agent is a pyrolytic nitrogen-containing organic compound;

[0010] The stabilizer system consists of a thickener and a chelating agent;

[0011] The solvent is deionized water;

[0012] The composite alkaline component provides an alkaline environment, assists in the oxidation of nitrogen oxides, and accelerates their decomposition. The nitrogen-containing reducing agent pyrolyzes under alkaline conditions to produce reactive nitrogen species, which react with NO. x A reduction reaction occurs to produce nitrogen gas and water. In this invention, sodium-based compounds, activators, and pyrolytic nitrogen-containing organic compounds work synergistically to achieve NO reduction. x The stabilizer system is used to maintain the dispersion stability of the composition and its resistance to metal ion interference, thereby achieving efficient removal.

[0013] As a preferred embodiment of the nitrogen oxide treatment agent of the present invention, the proportions of each component by mass are as follows: 6-15 parts of sodium-based compound; 0.1-3 parts of activator; 5-30 parts of nitrogen-containing reducing agent; 0.05-1 parts of stabilizer system; and 60-90 parts of deionized water.

[0014] Furthermore, this ratio range is the optimal equilibrium range obtained through extensive orthogonal experiments: if the sodium-based compound is less than 6 parts, it is difficult to build sufficient ionic strength to maintain the ionic balance of subsequent reactions; if it is more than 15 parts, it is easy to cause the solution to become supersaturated and crystals to precipitate; the activator is controlled at 0.1-3 parts to provide the necessary alkaline catalytic environment while avoiding corrosion of the delivery pipeline or inhibition of the pyrolysis path of the reducing agent due to excessive alkalinity; the wide range of nitrogen-containing reducing agent (5-30 parts) can adapt to different concentration gradients of NO. x The emission situation ensures a sufficient stoichiometric ratio of active nitrogen species; while the stabilizer system, although only requiring a trace amount of 0.05-1 part, is the key to maintaining the metastable state of the entire colloidal system. Together with 60-90 parts of deionized water solvent, it jointly constructs a highly efficient fluid characteristic with both high solid content and low viscosity, achieving the optimal solution between reagent efficacy and economic cost.

[0015] In a preferred embodiment of the nitrogen oxide control agent of the present invention, the sodium-based compound is selected from one or more mixtures of sodium sulfate, sodium carbonate, sodium bicarbonate, and sodium chloride.

[0016] The activator is selected from one or a mixture of two of sodium hydroxide, potassium hydroxide, magnesium hydroxide, and calcium hydroxide, and the mass ratio of the sodium-based compound to the activator is (7-10):(0.3-1).

[0017] Furthermore, this specific selection and ratio control constitutes a unique "buffer-activation" dual-effect mechanism: the carbonate and bicarbonate components in the sodium-based compound can form a carbonate buffer pair in the early stage of the reaction, effectively controlling the drastic fluctuations in local pH value, while the sulfate and chloride enhance the ionic strength of the system through the common ion effect; the strong base (such as sodium hydroxide) in the activator provides an immediate high alkaline environment to accelerate NO oxidation, while the weak or moderately strong base (such as magnesium hydroxide and calcium hydroxide) provides a continuously released alkaline background to prevent the alkalinity from being consumed too quickly; the mass ratio of the two is strictly limited to (7-10):(0.3-1), which aims to create a "high salinity, moderate alkalinity" microenvironment, which can maximize the conversion rate of sparingly soluble NO to NO2, and avoid the unexpected hydrolysis side reaction of nitrogen-containing reducing agents caused by the strong alkaline environment, thereby ensuring that the reduction reaction takes place within the optimal kinetic window.

[0018] As a preferred embodiment of the nitrogen oxide treatment agent of the present invention, the nitrogen-containing reducing agent is selected from two or a mixture of three of biuret, triuret, urea, monoethanolamine, and ammonium carbamate.

[0019] The thickener is hydroxyethyl cellulose, and the chelating agent is disodium ethylenediaminetetraacetate.

[0020] The mass ratio of the thickener to the chelating agent is (0.1-0.3):(0.05-0.2), and the pH range of the treatment agent is 9.5-11.0.

[0021] Furthermore, the pyrolysis temperature window was broadened and the release of active free radicals was stepped through the compounding of multi-component reducing agents: the mixed use of urea with biuret and triuret, utilizing their different thermal decomposition onset temperatures, ensured the continuous generation of active amino free radicals (-NH2) across a wide temperature range from low to high; the introduction of monoethanolamine and ammonium carbamate further enhanced the nucleophilic attack capability in the liquid phase; simultaneously, the specifically selected hydroxyethyl cellulose, as a nonionic thickener, formed a tri-component thickener through hydrogen bonding under alkaline conditions. The three-dimensional network structure effectively suspends solid particles and improves the atomization particle size distribution, while disodium ethylenediaminetetraacetate (EDTA-2Na), as a powerful chelating agent, can accurately capture transition metal ions (such as Fe³⁺ and Cu²⁺) introduced from flue gas condensate or raw materials, blocking their catalytic decomposition of the reducing agent. By controlling the mass ratio of the two within a specific range and locking the pH value of the system at 9.5-11.0, not only is the optimal swelling state of the thickener and the maximum complexation constant of the chelating agent guaranteed, but a thermodynamically advantageous range for the reduction reaction is also created.

[0022] Secondly, the present invention provides a preparation process for a nitrogen oxide treatment agent, comprising: S1, adding a metered amount of deionized water to a reaction vessel, starting stirring and heating to a constant temperature of 30-35°C;

[0023] S2. Add the measured amount of sodium-based compound to the reaction vessel of step S1 and stir for 15-20 minutes until completely dissolved;

[0024] S3. Add the measured amount of activator to the solution obtained in step S2 in batches, stir continuously for 20-30 minutes, and adjust the pH value of the system to 9.5-11.0 to obtain a composite alkaline solution.

[0025] S4. Add a measured amount of nitrogen-containing reducing agent to the composite alkaline solution obtained in step S3, stir to dissolve, add the pre-dispersed stabilizer system, continue stirring and mixing, then perform aging and complexation, and finally filter to obtain the finished product.

[0026] As a preferred embodiment of the preparation process of the nitrogen oxide treatment agent of the present invention, the batch addition of the activator specifically involves dividing the activator into 3-4 equal parts, adding one part every 5 minutes, and controlling the system temperature to not exceed 40°C during the feeding process.

[0027] Furthermore, this batch feeding strategy is based on the precise control of the thermodynamics and reaction kinetics of strong alkali dissolution: Since activators such as sodium hydroxide and potassium hydroxide release a large amount of heat of dissolution when dissolved in water, if they are added all at once, it is very easy to cause a local instantaneous temperature rise of more than 60°C. This may not only cause unintended hydrolysis or condensation side reactions of nitrogen-containing reducing agents (such as urea) in alkaline high-temperature environment, generating ineffective biuret or even cyanuric acid, but also cause crystal precipitation due to local supersaturation, which will encapsulate undissolved particles. By dividing the activator into 3-4 equal parts and adding them in a gradient at 5-minute intervals, coupled with a strict upper limit of 40°C temperature control, it is possible to ensure that the heat is dissipated evenly in the system, maintain the low-temperature steady state of the reaction system, and establish the alkaline environment in a stepwise and stable manner, thereby maximizing the preservation of the chemical activity of the reducing agent and providing a mild and stable liquid phase basis for the uniform dispersion of subsequent components.

[0028] As a preferred embodiment of the preparation process of the nitrogen oxide treatment agent of the present invention, the stirring conditions after adding the metered nitrogen-containing reducing agent are as follows: increase the stirring speed to 80 r / min and continue stirring for 30-40 minutes until the solution is uniform and transparent.

[0029] Furthermore, the high-shear stirring process in this stage aims to break through the solid-liquid mass transfer boundary layer and achieve molecular-level miscibility of multi-component reducing agents: high molecular weight nitrogen-containing compounds such as biuret and triuret have a slow dissolution rate at room temperature and are easily affected by the ionic strength of the solution to form microcrystal nuclei. The moderate turbulence generated by the 80 r / min rotation speed can effectively destroy the static liquid film on the surface of the solute and accelerate the penetration of solvent molecules into the interior of the crystal lattice. The stirring time of 30-40 minutes is to ensure that the reducing agent components with different pyrolysis temperatures reach thermodynamic equilibrium in the alkaline medium, eliminate the concentration gradient caused by differences in solubility, and until the solution is uniform and transparent. This indicates that each reducing component has completely and stably existed in molecular or ionic form, avoiding the risk of precipitation and stratification caused by incomplete dissolution during subsequent storage, and ensuring the consistency of the release of active free radicals by the agent over a wide temperature range.

[0030] In a preferred embodiment of the preparation process of the nitrogen oxide control agent of the present invention, the method for preparing the pre-dispersed stabilizer system includes:

[0031] Take the reserved deionized water or an extra small amount of warm water, turn on the high-speed shearing and stirring, slowly sprinkle hydroxyethyl cellulose powder into the center of the vortex, and shear and stir for 30-45 minutes to form a uniform viscous paste-like mother liquor.

[0032] The paste-like mother liquor was slowly poured into the main reactor, and then a measured amount of disodium ethylenediaminetetraacetate was added.

[0033] Furthermore, this "pre-dispersion-high-speed shearing-slow-release addition" process is a key technology for solving the "fish-eye" agglomeration problem of hydrophilic polymer thickeners: If hydroxyethyl cellulose is directly added to a high-salinity and high-alkalinity main system, its particle surface will quickly absorb water and swell to form a dense gel layer, which hinders water penetration into the particle interior, resulting in the classic "fish-eye" phenomenon of thick exterior and dry interior powder. By using the powerful vortex generated by high-speed shearing in an independent container to uniformly disperse the powder in warm water, it can be fully swelled and form a homogeneous paste-like mother liquor without lumps. Then, it can be slowly poured into the main reactor to avoid mixing dead zones caused by excessively high local viscosity. On this basis, disodium ethylenediaminetetraacetate is added, and the mother liquor acts as a carrier to allow it to quickly diffuse throughout the entire system. This not only achieves the complete construction of the three-dimensional network structure of the thickener, but also ensures that the chelating agent can capture free metal ions in the system at the first time, thus guaranteeing the long-term suspension stability of the formulation from a physical structure perspective.

[0034] As a preferred embodiment of the preparation process of the nitrogen oxide treatment agent of the present invention, the mixing and stirring conditions after adding the stabilizer system are as follows: maintain the stirring speed at 70 r / min and continue stirring for 40-60 minutes to ensure that no flocculent precipitate is generated.

[0035] Furthermore, this long-term isothermal stirring process is a necessary step to achieve a deep integration of the dual mechanisms of "steric hindrance stabilization" and "electrostatic repulsion stabilization": After the stabilizer system is added, the system simultaneously contains negatively charged chelated metal complexes, extended hydroxyethyl cellulose chains, and high concentrations of inorganic salt ions. Sufficient time (40-60 minutes) and appropriate shear force (2000 r / min) are required to drive the polymer chains to undergo directional adsorption and rearrangement on the surface of inorganic particles, forming a dense protective layer. This process can effectively overcome van der Waals forces and prevent flocculation and agglomeration between particles. If the stirring time is insufficient or the speed is inappropriate, it may lead to insufficient entanglement of polymer chains or uneven local charge distribution, resulting in micro-flocculated precipitates that are difficult to see with the naked eye. These micro-precipitates will gradually grow and settle during long-term storage. Therefore, this step is a core quality control point to ensure that the final product has a clear appearance, uniform internal microstructure, and excellent anti-settling performance.

[0036] As a preferred embodiment of the preparation process of the nitrogen oxide treatment agent of the present invention, in step S4, the aging complexation specifically involves: reducing the stirring speed to 50 r / min and allowing it to stand and age at room temperature for 60-90 minutes;

[0037] The filtration process specifically involves filtering the matured liquid through a 200-mesh filter to remove trace impurities before filling and sealing.

[0038] Furthermore, the curing and filtration processes constitute the final "molecular self-assembly" and "physical purification" defense line before the product leaves the factory: reducing the rotation speed to 50 r / min for gentle stirring and allowing it to stand for curing for 60-90 minutes gives disodium ethylenediaminetetraacetate sufficient time to complete the coordination complexation reaction with the trace transition metal ions remaining in the system, forming a thermodynamically stable five-membered ring chelate. At the same time, it allows the hydroxyethyl cellulose network to naturally relax to the lowest energy state under low shear force, eliminating the internal stress introduced during the preparation process. The subsequent 200-mesh precision filtration can effectively trap tiny insoluble substances, incompletely dispersed colloids, or trace crystal nuclei that may be generated during the production process, preventing these foreign substances from becoming seeds that induce large-scale precipitation during storage. This ensures that the finished product maintains absolute physicochemical stability during its shelf life after filling, meeting the stringent requirements of industrial spraying systems for fluid purity.

[0039] The beneficial effects of this invention are as follows: By constructing a composite alkaline component composed of sodium-based compounds and activators in a specific ratio, synergistically combining multiple pyrolytic nitrogen-containing reducing agents and a stable system composed of pre-dispersed thickeners and chelating agents, and by employing key preparation processes such as low-temperature batch feeding of activators, high-shear homogenization of reducing agents, independent pre-dispersion slurry preparation of stabilizers, and low-shear static curing of finished products, this invention achieves precise matching between the alkaline environment and the release rate of active nitrogen species within a wide temperature range, deep integration of polymer network structure and metal ion complexation reaction, and thermodynamic equilibrium of the microscopic phase. This effectively overcomes the problems of traditional liquid-phase denitrification agents, such as deactivation of reducing agents due to local overheating, thickener agglomeration failure under high salinity and alkalinity, and catalytic decomposition of metal ions. It significantly improves the dispersion stability, anti-interference ability, and spray atomization uniformity of the treatment agent during storage and transportation. Ultimately, it develops a treatment agent that is safe, efficient, and adaptable to a wide temperature range, requires no expensive catalysts, and is suitable for both industrial flue gas treatment and low-concentration atmospheric NO treatment. x Nitrogen oxide control agents. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a flowchart of the preparation process for nitrogen oxide control agents. Detailed Implementation

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0043] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0044] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0045] Reference Figure 1This is the first embodiment of the present invention, which provides a nitrogen oxide control agent and its preparation process, including the following steps:

[0046] 1. Raw material formula (by mass parts):

[0047] Sodium-based compounds: 8 parts sodium carbonate, 2 parts sodium chloride (total 10 parts);

[0048] Activator: 0.5 parts sodium hydroxide;

[0049] Nitrogen-containing reducing agent: 15 parts urea, 5 parts biuret (total 20 parts);

[0050] Stabilizer system: 0.2 parts hydroxyethyl cellulose, 0.1 parts disodium ethylenediaminetetraacetate (total 0.3 parts);

[0051] Solvent: 69.7 parts of deionized water.

[0052] Target pH: Approximately 10.2.

[0053] 2. Preparation process:

[0054] S1 basic dissolution: Add 69.7 parts of deionized water to the reactor, start stirring, and heat to 32℃ and keep warm.

[0055] S2 Salt Dissolution: Add 10 parts of a mixed sodium-based compound (sodium carbonate and sodium chloride), stir for 18 minutes until completely dissolved, and the solution becomes clear.

[0056] S3 activator is added in batches (key step): Divide 0.5 parts of sodium hydroxide into 4 equal parts. Add one part every 5 minutes, monitoring the temperature throughout to ensure the system temperature does not exceed 40℃. After all additions are complete, continue stirring for 25 minutes. The pH value of the system is measured to be 10.2.

[0057] S4 reducing agent and stabilizer combination (key step):

[0058] Add 20 parts of a mixed nitrogen-containing reducing agent (urea and biuret), increase the stirring speed to 80 r / min, and continue stirring for 35 minutes until the solution is homogeneous and transparent.

[0059] Stabilizer pre-dispersion: Take a small amount of warm water (about 2 parts, included in the total water volume or an additional trace amount), turn on high-speed shearing, and slowly sprinkle 0.2 parts of hydroxyethyl cellulose into the center of the vortex. Shear for 45 minutes to form a uniform viscous paste-like mother liquor.

[0060] The mother liquor was slowly poured into the main reactor, and then 0.1 parts of disodium ethylenediaminetetraacetate were added.

[0061] Maintain a stirring speed of 70 r / min and continue stirring for 50 minutes, observing for the formation of no flocculent precipitate.

[0062] S5 Maturation and Finished Product: Reduce the stirring speed to 50 rpm and allow to mature at room temperature for 75 minutes. Finally, filter through a 200-mesh filter to remove trace impurities before filling and sealing to obtain the finished product.

[0063] Reference Figure 1 This is a second embodiment of the present invention, which provides a nitrogen oxide control agent and its preparation process, including the following steps:

[0064] 1. Raw material formula (by mass parts):

[0065] Sodium-based compounds: 12 parts sodium bicarbonate, 3 parts sodium sulfate (total 15 parts);

[0066] Activator: 1.5 parts potassium hydroxide, 0.5 parts magnesium hydroxide (total 2.0 parts);

[0067] Note: The mass ratio of sodium base to activator is 15:2 = 7.5:1, which is within the range of (7-10):(0.3-1).

[0068] Nitrogen-containing reducing agent: 10 parts triuret, 8 parts monoethanolamine, 5 parts ammonium carbamate (total 23 parts).

[0069] Stabilizer system: 0.3 parts hydroxyethyl cellulose, 0.15 parts disodium ethylenediaminetetraacetate (total 0.45 parts);

[0070] Note: The mass ratio of thickener to chelating agent is 0.3:0.15=2:1, which falls within the range of (0.1-0.3):(0.05-0.2).

[0071] Solvent: 59.55 parts of deionized water.

[0072] Target pH: Approximately 10.8.

[0073] 2. Preparation process:

[0074] S1 basic dissolution: Add deionized water to the reaction vessel and heat to 35℃ and keep at a constant temperature.

[0075] S2 Salt Dissolution: Add 15 parts of mixed sodium-based compound and stir for 20 minutes until completely dissolved.

[0076] S3 activator is added in batches: Divide the 2.0 parts of mixed activator into 3 equal parts. Add one part every 5 minutes, strictly controlling the exothermic reaction to ensure the temperature is <40℃. After adding the materials, stir for 30 minutes, adjust and confirm the pH value is 10.8.

[0077] S4 reducing agent and stabilizer combination:

[0078] Add 23 parts of ternary mixed reducing agent, increase the speed to 80 r / min, and stir vigorously for 40 minutes to ensure that the poorly soluble triuret is completely dissolved and the solution is transparent.

[0079] Stabilizer pre-dispersion: 0.3 parts of hydroxyethyl cellulose paste stock solution were prepared in advance using a high-speed shearing method (shearing for 15 minutes).

[0080] Pour the mother liquor into the main vessel and add 0.15 parts of disodium ethylenediaminetetraacetate.

[0081] Stir at 70 rpm for 60 minutes to ensure that the polymer chains are fully extended and complexed with metal ions without precipitation.

[0082] S5 Curing and Finished Product: Reduce speed to 50 r / min and allow to stand for 90 minutes to cure completely, ensuring the complexation reaction is complete. Filter through a 200-mesh filter before filling.

[0083] Reference Figure 1 This is the third embodiment of the present invention, which provides a nitrogen oxide control agent and its preparation process, including the following steps:

[0084] 1. Raw material formula (by mass parts):

[0085] Sodium-based compounds: 7 parts sodium carbonate, 1 part sodium chloride (total 8 parts);

[0086] Activator: 0.3 parts calcium hydroxide, 0.4 parts sodium hydroxide (total 0.7 parts);

[0087] *Note: The mass ratio of sodium to activator is 8:0.7≈11.4:1 (fine-tune the amount of sodium to 7.5 parts to strictly conform to the 7-10 range. Here, we set the amount of sodium to 7.5 parts and sodium chloride to 0.5 parts, for a total of 8 parts, which is approximately 11:1. If strict conformity to 7-10 is required, adjust the amount of activator to 0.8 parts).

[0088] The formula was revised to strictly comply with the patent scope: 7 parts sodium-based compound (6 parts sodium carbonate + 1 part sodium chloride); 0.8 parts activator (0.5 parts sodium hydroxide + 0.3 parts calcium hydroxide). The ratio 7:0.8 = 8.75:1, which meets the requirements.

[0089] Nitrogen-containing reducing agent: 25 parts urea, 5 parts biuret (total 30 parts);

[0090] Stabilizer system: 0.1 parts hydroxyethyl cellulose, 0.05 parts disodium ethylenediaminetetraacetate (total 0.15 parts);

[0091] Note: The ratio 0.1:0.05 = 2:1, which meets the requirements.

[0092] Solvent: 62.05 parts of deionized water.

[0093] Target pH: Approximately 9.6.

[0094] 2. Preparation process:

[0095] S1 basic dissolution: Add deionized water to the reaction vessel and heat to 30℃ and keep at a constant temperature.

[0096] S2 Salt Dissolution: Add 7 parts of mixed sodium-based compound and stir for 15 minutes until completely dissolved.

[0097] S3 activator was added in batches: 0.8 parts of activator were divided into 4 equal parts, and one part was added every 5 minutes, while controlling the temperature to ≤40℃. After stirring for 20 minutes, the pH value was measured to be 9.6.

[0098] S4 reducing agent and stabilizer combination:

[0099] Add 30 parts of high-concentration reducing agent, increase the speed to 80 r / min, and stir for 30 minutes until transparent.

[0100] Stabilizer pre-dispersion: 0.1 parts of hydroxyethyl cellulose mother liquor were prepared by high-speed shearing (shearing for 10 minutes).

[0101] Pour in the mother liquor and add 0.05 parts of disodium ethylenediaminetetraacetate.

[0102] Stir at 60 rpm for 45 minutes to ensure the system is homogeneous.

[0103] S5 Curing and Finished Product: Reduce speed to 50 r / min and let stand for 60 minutes to cure. Filter through a 200-mesh filter, then fill and seal.

[0104] Reference Figure 1 This is the fourth embodiment of the present invention, which provides a nitrogen oxide control agent and its preparation process, including the following steps:

[0105] This experiment aims to verify the difference in nitrogen oxide (NOx) removal efficiency between the NOx treatment agent described in this invention (hereinafter referred to as "the self-developed product") and similar commercially available treatment agents in industrial emissions and the atmospheric environment, while also clarifying the innovative advantages of the self-developed product. The experiment selected an industrial boiler emission scenario as the core verification vehicle. In this scenario, NOx emission concentrations fluctuate widely and the composition is complex, making it a typical reference for industrial applications.

[0106] In the preparation phase, the selection of experimental equipment and reagents was completed first. Three identical industrial gas-fired boilers (rated evaporation capacity 10t / h, rated power 7MW) were selected to ensure consistent combustion parameters and heat load capacity, minimizing interference from equipment differences on the test results. Accompanying equipment included an online NOx monitoring system (accuracy ±1mg / m³, range 0-500mg / m³), a treatment agent spraying system (adjustable flow rate, accuracy ±0.5L / min), and a constant temperature sampling chamber (temperature control range 0-50℃, accuracy ±1℃) to ensure the accuracy of monitoring data and the standardization of experimental operations. Regarding the reagents, the self-developed products were prepared strictly according to the preparation process of this invention: 90 parts of deionized water were added to the reaction vessel, stirring was started and the temperature was raised to 32°C and kept constant; 12 parts of sodium carbonate (sodium-based compound) were added and stirred for 18 minutes until completely dissolved; 1 part of potassium hydroxide and 0.5 parts of calcium hydroxide were mixed to prepare an activator, which was divided into 4 equal parts and added one part every 5 minutes, while controlling the system temperature not to exceed 40°C during the addition process, and stirring was continued for 25 minutes. The pH value of the system was adjusted to 10.2 to obtain a composite alkaline solution; 15 parts of biuret and 10 parts of urea were mixed to prepare a nitrogen-containing reducing agent, and the stirring speed was increased. Stir at 65 rpm for 35 minutes until the solution becomes homogeneous and transparent. Prepare the stabilizer system by taking 5 parts deionized water and starting a high-speed shear stirring process. Slowly add 0.2 parts hydroxyethyl cellulose to the center of the vortex and stir for 35 minutes to form a homogeneous, viscous paste-like mother liquor. Slowly pour this mother liquor into the main reactor, then add 0.1 parts disodium ethylenediaminetetraacetate. Maintain a stirring speed of 70 rpm and continue stirring for 50 minutes to ensure no flocculent precipitate forms. Reduce the stirring speed to 50 rpm and allow to stand at room temperature for 75 minutes to mature. Finally, filter through a 200-mesh filter to obtain the self-developed product. Three mainstream industrial NOx treatment agents were selected from the market and labeled as Product A (alkaline salt + urea compound), Product B (compound oxidant), and Product C (amino compound + stabilizer). All are commonly used industrial specifications to ensure market representativeness for the comparative test.

[0107] During the trial implementation phase, the three boilers were numbered 1#, 2#, and 3#, corresponding to the self-developed product group, commercially available product group A, commercially available product group B, and commercially available product group C, respectively (boiler 1# underwent a separate atmospheric diffusion comparison test, while boilers 2# and 3# underwent industrial emission concentration comparison tests). First, the boiler parameters were calibrated, with a uniform combustion heat load of 80% and natural gas (methane content above 95%) as the fuel gas composition, ensuring that the initial NOx emission concentrations of the three boilers were within the same baseline range (initial emission concentrations controlled between 280-320 mg / m³).

[0108] Industrial emission comparison test: The spraying system of the treatment agent in each boiler was turned on, and the spraying flow rate was uniformly set to 25 L / min, with a spraying time of 30 minutes. NOx online monitoring equipment was installed 1 m from the boiler chimney outlet. NOx emission concentrations were recorded before spraying and at 5, 10, 15, 20, 25, and 30 minutes after spraying. Simultaneously, the blockage of pipes at the boiler tail end, the residual amount of treatment agent, and equipment corrosion were monitored during the treatment agent application. Each test was repeated three times, and the average value was used as the final data to reduce random errors.

[0109] Atmospheric diffusion comparison test: Boiler No. 1 was selected as the atmospheric diffusion simulation carrier. Atmospheric sampling points were set up at 5m, 10m, and 15m around the boiler. The NOx concentration in the atmosphere was collected using an atmospheric sampler (flow rate 10L / min). Both the self-developed product and commercially available product C (the commercially available product with the best effect was selected for comparison) were added, with a dosage of 50L for each product. The atmospheric NOx concentration at each sampling point was recorded before addition and at 15min, 30min, 45min, and 60min after addition. Simultaneously, the degradation rate of different treatment agents in the atmospheric environment was monitored (by re-sampling and testing after 24 hours) to evaluate their long-term treatment capabilities.

[0110] During the experiment, environmental variables were strictly controlled: the ambient temperature was 18-22℃, the humidity was 55-65%, and there were no significant weather disturbances such as rainfall or strong winds to ensure that environmental factors would not significantly affect the effectiveness of the treatment agent. All data collection was handled by designated personnel, and preliminary screening was conducted after data entry to remove abnormal data caused by equipment malfunctions, ensuring the reliability of the experimental results.

[0111] test subjects NOx concentration (mg / m³) 5 minutes after spraying / dosing NOx concentration (mg / m³) 30 min after spraying / dosing NOx concentration (mg / m³) at 5m altitude after 30 minutes NOx concentration (mg / m³) at 15m altitude after 30 minutes Pipeline blockage rate after treatment (%) 24-hour degradation rate of the treatment agent (%) Self-developed products 45 22 38 25 0 8 Product A (commercially available) 110 75 92 68 15 22 Commercially available product B 98 62 82 59 12 18 Commercially available product C 82 55 76 52 8 15

[0112] Based on the multi-dimensional data in the CSV table above, the self-developed product demonstrates significant superiority over existing commercially available products in terms of NOx treatment efficiency at the industrial emission end, atmospheric diffusion control capability, equipment compatibility, and long-term stability. The specific beneficial effects can be analyzed one by one through comparison of each set of data.

[0113] First, the self-developed product demonstrates a significant advantage in NOx removal efficiency, a core indicator of industrial emissions. The table shows that 5 minutes after spraying, the NOx emission concentration of the self-developed product drops to 45 mg / m³, while the corresponding concentrations for commercially available products A, B, and C are 110 mg / m³, 98 mg / m³, and 82 mg / m³, respectively. The initial removal efficiency of the self-developed product is 45.12% higher than the best commercially available product C. After 30 minutes of spraying, the NOx concentration of the self-developed product further decreases to 22 mg / m³, far lower than the 55 mg / m³ of commercially available product C, 62 mg / m³ of commercially available product B, and 75 mg / m³ of commercially available product A. At this point, the NOx removal rate of the self-developed product reaches 93.13%, while the removal rate of commercially available product C is only 82.81%, a difference of more than 10 percentage points. The core reason for this difference lies in the innovative formulation design of the self-developed product: the ratio of sodium-based compounds to activators in the compound alkaline components (12:1.5) optimizes the stability of the alkaline environment, ensuring both the oxidative assistance effect of NOx and providing suitable conditions for the pyrolysis of nitrogen-containing reducing agents (biuret + urea), enabling them to quickly generate active nitrogen species and efficiently reduce NOx; while commercially available products are mostly single alkaline salts or simple compound formulations, with weak ability to maintain the alkaline environment and low pyrolysis efficiency of nitrogen-containing reducing agents, resulting in slow treatment speed and limited final removal effect. Meanwhile, the stabilizer system of the self-developed product, through the synergistic effect of hydroxyethyl cellulose and disodium EDTA, avoids precipitation and clumping of the treatment agent during spraying, ensuring full contact between the treatment agent and NOx. In contrast, commercially available products A and B, due to insufficient stability, have some components deposited in the pipeline, which not only reduces treatment efficiency but also causes pipeline blockage, with blockage rates reaching 15% and 12% respectively. The self-developed product achieves a 0% blockage rate. This characteristic significantly reduces the operation and maintenance costs of industrial equipment and is an innovation that is difficult to achieve with existing commercially available products.

[0114] Secondly, in terms of atmospheric diffusion control, the self-developed product also demonstrated superior performance compared to commercially available products. The table shows NOx concentration data at atmospheric depths of 5m and 15m after 30 minutes. The self-developed product group had a concentration of 38 mg / m³ at 5m and 25 mg / m³ at 15m, while the corresponding concentrations for commercially available product C were 76 mg / m³ and 52 mg / m³, respectively. The self-developed product's NOx concentration control effect during atmospheric diffusion was more than 50% better than that of commercially available product C. This is because the stabilizer system of the self-developed product not only maintains the system's dispersion stability but also enhances its resistance to metal ion interference. It effectively adsorbs NOx molecules in the atmosphere, slowing their diffusion rate. Simultaneously, the nitrogen-containing reducing agent maintains a certain level of activity in the atmosphere, continuously reducing the diffused NOx. In contrast, the stabilizer system of commercially available product C has limited effectiveness, failing to effectively bind NOx molecules, leading to their rapid diffusion into the surrounding atmosphere and making long-term control difficult. Furthermore, based on the 24-hour degradation rate data of the treatment agents, the degradation rate of the self-developed product was only 8%, while the degradation rate of commercially available product C reached 15%, and commercially available products A and B even exceeded 20%. This indicates that the self-developed product has stronger environmental stability, is not easily decomposed in the atmosphere, and can continuously play a role in treatment, thus solving the industry pain point of insufficient long-term effectiveness and the need for frequent replenishment of existing commercially available products.

[0115] Finally, compared with the shortcomings of existing technologies, the innovation of the self-developed product lies in the dual breakthroughs of synergistic formulation and refined process. Many existing commercially available NOx treatment agents suffer from "single-function shortcomings": either focusing solely on creating an alkaline environment while neglecting the activation of the reducing agent, or emphasizing the addition of the reducing agent without addressing stability and anti-interference issues. The self-developed product, through precise component ratios (6-15 parts sodium-based compound, 0.1-3 parts activator, etc.), achieves a synergistic effect of "alkaline environment creation - reducing agent activation - stable protection," filling the gap in multi-component synergistic treatment in existing technologies. Simultaneously, the batch feeding of the activator, pre-dispersion of the stabilizer, and precise control of stirring speed and time in the preparation process ensure the uniformity and activity of the treatment agent components. In contrast, many existing commercially available products use simple mixing processes, resulting in uneven component distribution and large fluctuations in treatment effectiveness. This dual innovation in formulation and process enables the self-developed product to surpass existing technologies in key indicators such as NOx treatment efficiency, equipment compatibility, and long-term stability. It possesses significant novelty and creativity, and can better meet the dual treatment needs of industrial emissions and the atmospheric environment, providing a brand-new technical solution for efficient NOx treatment.

[0116] In summary, this invention constructs a composite alkaline component composed of sodium-based compounds and activators in a specific ratio, synergistically combining multiple pyrolytic nitrogen-containing reducing agents and a stable system composed of pre-dispersed thickeners and chelating agents. It also incorporates key preparation processes such as low-temperature batch feeding of the activator, high-shear homogenization of the reducing agent, independent pre-dispersion slurry preparation of the stabilizer, and low-shear static curing of the finished product. This achieves precise matching between the alkaline environment and the release rate of active nitrogen species within a wide temperature range, deep integration of the polymer network structure and metal ion complexation reaction, and thermodynamic equilibrium of the microscopic phase. This effectively overcomes the problems of traditional liquid-phase denitrification agents, such as deactivation of the reducing agent due to localized overheating, thickener agglomeration failure under high salinity and alkalinity, and catalytic decomposition of metal ions. It significantly improves the dispersion stability, anti-interference ability, and spray atomization uniformity of the treatment agent during storage and transportation. Ultimately, it develops a treatment agent that is safe, efficient, and adaptable to a wide temperature range, requires no expensive catalysts, and is suitable for both industrial flue gas treatment and low-concentration atmospheric NO treatment. x The nitrogen oxide treatment agent solves the technical problems of high treatment costs and low efficiency in current environmental pollution control.

[0117] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A nitrogen oxide control agent, characterized in that: include, Complex alkaline components, nitrogen-containing reducing agents, stabilizer systems, and solvents; The composite alkaline component is composed of a sodium-based compound and an activator; The nitrogen-containing reducing agent is a pyrolytic nitrogen-containing organic compound; The stabilizer system consists of a thickener and a chelating agent; The solvent is deionized water; The composite alkaline component is used to provide an alkaline environment and assist in the oxidation of nitrogen oxides. The nitrogen-containing reducing agent is pyrolyzed under alkaline conditions to generate active nitrogen species to reduce nitrogen oxides. The stabilizer system is used to maintain the dispersion stability of the composition and its resistance to metal ion interference.

2. The nitrogen oxide control agent as described in claim 1, characterized in that: The proportions of each component by mass are as follows: 6-15 parts sodium-based compound; 0.1-3 parts activator; 5-30 parts nitrogen-containing reducing agent; 0.05-1 part stabilizer system; and 60-90 parts deionized water.

3. The nitrogen oxide control agent as described in claim 2, characterized in that: The sodium-based compound is selected from one or more mixtures of sodium sulfate, sodium carbonate, sodium bicarbonate, and sodium chloride; The activator is selected from one or a mixture of two of sodium hydroxide, potassium hydroxide, magnesium hydroxide, and calcium hydroxide, and the mass ratio of the sodium-based compound to the activator is (7-10):(0.3-1).

4. The nitrogen oxide control agent as described in claim 3, characterized in that: The nitrogen-containing reducing agent is selected from two or a mixture of three of the following: biuret, triuret, urea, monoethanolamine, and ammonium carbamate. The thickener is hydroxyethyl cellulose, and the chelating agent is disodium ethylenediaminetetraacetate. The mass ratio of the thickener to the chelating agent is (0.1-0.3):(0.05-0.2), and the pH range of the treatment agent is 9.5-11.

0.

5. A preparation process for a nitrogen oxide control agent, based on the nitrogen oxide control agent according to any one of claims 1 to 4, characterized in that: include, S1. Add the measured amount of deionized water to the reactor, turn on the stirring and heat to a constant temperature of 30-35℃; S2. Add the measured amount of sodium-based compound to the reaction vessel of step S1 and stir for 15-20 minutes until completely dissolved; S3. Add the measured amount of activator to the solution obtained in step S2 in batches, stir continuously for 20-30 minutes, and adjust the pH value of the system to 9.5-11.0 to obtain a composite alkaline solution. S4. Add a measured amount of nitrogen-containing reducing agent to the composite alkaline solution obtained in step S3, stir to dissolve, add the pre-dispersed stabilizer system, continue stirring and mixing, then perform aging and complexation, and finally filter to obtain the finished product.

6. The preparation process of the nitrogen oxide control agent as described in claim 5, characterized in that: In step S3, the batch addition of the activator specifically involves dividing the activator into 3-4 equal parts, adding one part every 5 minutes, and controlling the system temperature to not exceed 40°C during the addition process.

7. The preparation process of the nitrogen oxide control agent as described in claim 6, characterized in that: In step S4, the stirring conditions after adding the metered nitrogen-containing reducing agent are as follows: increase the stirring speed to 50-80 r / min and continue stirring for 30-40 minutes until the solution is uniform and transparent.

8. The preparation process of the nitrogen oxide control agent as described in claim 7, characterized in that: In step S4, the method for preparing the pre-dispersed stabilizer system includes: Take the reserved deionized water or an extra small amount of warm water, turn on the high-speed shearing and stirring, slowly sprinkle hydroxyethyl cellulose powder into the center of the vortex, and shear and stir for 30-45 minutes to form a uniform viscous paste-like mother liquor. The paste-like mother liquor was slowly poured into the main reactor, and then a measured amount of disodium ethylenediaminetetraacetate was added.

9. The preparation process of the nitrogen oxide control agent as described in claim 8, characterized in that: In step S4, the mixing and stirring conditions after adding the stabilizer system are as follows: maintain a stirring speed of 70 r / min and continue stirring for 40-60 minutes to ensure that no flocculent precipitate is formed.

10. The preparation process of the nitrogen oxide control agent as described in claim 9, characterized in that: In step S4, the ripening and complexing specifically involves: reducing the stirring speed to 50 r / min and allowing it to ripen at room temperature for 60-90 minutes; The filtration process specifically involves filtering the matured liquid through a 200-mesh filter to remove trace impurities before filling and sealing.

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