A purification method for NO x Multifunctional powders containing SO2 and CO, their preparation methods and applications

Abstract

The application discloses a multifunctional powder for purifying NO x , SO2 and CO as well as a preparation method and application of the multifunctional powder. The catalyst is prepared by taking transition metal oxides and light rare earth metal as active components, taking diatomite saturated adsorption of strong oxidant solution and then drying to obtain an oxidant, and taking a composite absorbent prepared by mixing fly ash, steel slag powder, alkali residue and sulfuric acid residue to obtain an absorbent. The multifunctional powder disclosed by the application can realize the collaborative treatment of multiple pollutants such as NO x , SO2 and CO, has simple preparation process, low operation cost, simple process, no secondary pollution and no corrosiveness to equipment, collaboratively solves the problem of resource utilization of industrial residues, and has great economic, environmental and social benefits.

Description

Technical Field

[0001] This invention provides a method for purifying NO x Multifunctional powders for SO2 and CO, their preparation methods and applications, belong to the technical fields of air pollution control, industrial pollution reduction and environmental catalytic materials. Technical Background

[0002] NO x The main technologies for treatment are wet denitrification, selective non-catalytic reduction (SNCR), and selective catalytic reduction (SCR). Among them, SCR denitrification technology has high efficiency and good stability, and has become the mainstream technology and development direction for industrial flue gas denitrification both domestically and internationally. x The main technologies for SO2 treatment include wet desulfurization, dry desulfurization, and semi-dry desulfurization. Among these, wet desulfurization is the most widely used, achieving SO2 removal rates of over 95%. Methods for CO removal include adsorption, CO methanation, and CO catalytic oxidation. Among these, CO catalytic oxidation technology has become the most important method and means for CO elimination due to its simplicity, low cost, and high efficiency. Currently, industrial coal-fired flue gas has a significant impact on NO2 removal. x The treatment of SO2 and CO mainly adopts a segmented integrated process of "desulfurization + denitrification + CO removal". Although it can purify pollutants, it requires a large area, has high investment costs, and high operating costs, placing a huge economic burden on enterprise users. In addition, the existing SCR denitrification technology is difficult to operate stably under the complex flue gas conditions in non-power industries, and wet desulfurization and denitrification processes suffer from severe equipment corrosion, easy gypsum rain, and large amounts of wastewater generation.

[0003] The semi-dry process involves a three-phase reaction of gas, liquid, and solid, offering high efficiency, low energy consumption, and minimal secondary pollution, making it widely used in desulfurization processes. Based on the principle of a circulating fluidized bed, the semi-dry process increases the contact time between the desulfurizing agent and flue gas through multiple cycles of the desulfurizing agent, thereby improving desulfurization efficiency and agent utilization. It is widely used in industries such as metallurgy and power generation. Therefore, regarding NO... x The purification of pollutants such as SO2 and CO is based on semi-dry processes. There is an urgent need to develop new multifunctional powders to replace desulfurizing agents, so as to achieve synergistic treatment of the three pollutants. The core of this research is multifunctional materials.

[0004] The large-scale discharge of industrial waste (fly ash, steel slag powder, alkaline slag, and sulfate ore slag, etc.) not only occupies a large amount of land but also causes serious pollution and harm to water systems and the atmosphere. The main method for resource-based treatment of industrial waste is its use in the production of lightweight bricks and cement (CN103936398A, CN104402270A, CN101182171A), but this method has low economic value. Industrial waste such as fly ash, steel slag powder, alkaline slag, and sulfate ore slag contain a large amount of alkaline components and some catalytic components, thus exhibiting excellent flue gas purification effects. Transition metal oxides and light rare earth minerals possess excellent catalytic properties, capable of catalytically oxidizing not only some CO to CO2 but also some NO and SO2, making them easier to absorb. Oxidants obtained by drying diatomaceous earth after saturation adsorption of strong oxidant solutions exhibit extremely strong oxidizing properties in contact with water in a circulating fluidized bed, effectively removing NO. x This method oxidizes SO2 and CO, achieving ultra-low emissions of all three. Simultaneously, the oxidant produced by this method effectively avoids equipment corrosion. Therefore, using industrial waste residue as the main absorbent, transition metal oxides and light rare earth minerals as catalytic components, and diatomaceous earth saturated with a strong oxidant solution followed by drying to obtain a powder as the oxidant, not only can the effect of "treating waste with waste" be achieved, realizing high-value resource utilization of industrial waste residue, but it can also produce multifunctional powders, simultaneously addressing NOx emissions from flue gas. x SO2 and CO control and industrial waste disposal issues. Summary of the Invention

[0005] This invention addresses the aforementioned technical problems by providing a method for purifying NO. x Multifunctional powders containing SO2 and CO, their preparation methods and applications.

[0006] The specific technical solution of this invention is as follows:

[0007] A purification method for NO x A multifunctional powder for SO2 and CO, comprising an absorbent, a catalyst, and an oxidant, wherein the mass ratio of absorbent:catalyst:oxidant is 1:(0.1-0.2):(0.1-0.2); the catalyst is composed of transition metal oxides and light rare earth minerals; the oxidant is prepared by drying diatomaceous earth saturated with a strong oxidant solution; the absorbent is a composite absorbent composed of fly ash, steel slag powder, alkaline slag, and sulfate ore slag, wherein the mass ratio of sulfate ore slag powder, fly ash, steel slag powder, and alkaline slag powder is 1:(0.1-10):(0.1-10):(0.1-10).

[0008] In the technical solution of this invention: the oxidant is prepared by stirring and dissolving hexaamminecobalt trichloride, potassium persulfate and deionized water to obtain an oxidant solution, adding diatomaceous earth to the solution, and drying the diatomaceous earth after saturation adsorption at 60-80℃ for 6-12 hours to obtain the oxidant.

[0009] The mass ratio of deionized water, hexaamminecobalt trichloride, and potassium persulfate is 1:(0.05-0.1):(0.05-0.1); the mass ratio of diatomaceous earth and oxidant solution is 1:1-5.

[0010] In the technical solution of this invention: the light rare earth mineral metal in the catalyst is at least one of La or Ce; the transition metal oxide is at least one of CoO, SnO2, Fe2O3, CuO, MnO2 or ZnO, and the mass ratio of the light rare earth mineral metal to the transition metal oxide is 1:(0.1~10);

[0011] Preferably, the transition metal oxide is three of the following: CoO, SnO2, Fe2O3, CuO, MnO2, or ZnO.

[0012] One of the above-mentioned purification NO x A method for preparing a multifunctional powder containing SO2 and CO is described, wherein the catalyst, oxidant and absorbent are mixed and ball-milled to form a multifunctional powder with a particle size of 80 to 300 mesh.

[0013] A method utilizing the above-mentioned multifunctional powder in NO2-containing coal-fired flue gas x Application of synergistic governance of SO2 and CO.

[0014] In the above applications: In flue gas areas with temperatures ranging from 80-300℃, the multifunctional powder is sprayed in. Under the convective impact of the flue gas, the multifunctional powder is dispersed and fully mixed with the flue gas, where CO is oxidized to CO2 and NO... x SO2 is catalyzed and adsorbed, generating harmless sulfates, nitrates, sulfites, or nitrites, thereby reducing NO in coal-fired flue gas. x Coordinated governance of SO2 and CO.

[0015] In the above applications, the mass ratio of the injected bifunctional powder to the mass of the flue gas is 1:0.1 to 2.

[0016] In the above applications, the flue gas velocity is 1 to 7 m / s.

[0017] Beneficial effects:

[0018] The multifunctional powder provided by this invention can achieve SO2, NO xIt can treat multiple pollutants such as CO in a coordinated manner, with high efficiency, simple process, no secondary pollution, low operating cost, low equipment requirements, low initial investment, little impact from operating conditions, and wide applicability. Detailed Implementation

[0019] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto.

[0020] In the flue gas region with temperatures ranging from 80 to 300°C, an injection inlet is selected, and multifunctional powder is weighed according to the metering ratio. Using a gas delivery pump, it is injected into the flue gas through the injection inlet. The injected multifunctional powder interacts with the flue gas through convection. Under the impact of the flue gas, the multifunctional powder is dispersed and fully mixed with the flue gas. CO is oxidized to CO2, and NO... x SO2 is catalyzed and adsorbed, generating harmless sulfates, nitrates, sulfites, or nitrites, which are then recovered and disposed of by a dust collector. Under conditions of a flue gas velocity of 6 m / s, uniform flow field mixing, and balanced temperature, the denitrification efficiency is over 90%, the desulfurization efficiency is close to 100%, and the CO removal efficiency is over 90%.

[0021] Example 1:

[0022] (1) Preparation of catalyst

[0023] The catalyst was obtained by weighing 100g of rare earth Ce and 10g of transition metal oxide (a mixture of CoO, ZnO and SnO2 with a mass ratio of 1:1:1) and mixing them thoroughly, according to the mass ratio of light rare earth mineral metal to transition metal oxide of 1:0.1.

[0024] (2) Preparation of oxidant

[0025] According to the mass ratio of deionized water: hexaamminecobalt trichloride: potassium persulfate of 1:0.05:0.05; and the mass ratio of diatomaceous earth: oxidant solution of 1:2.5, 5g of hexaamminecobalt trichloride, 5g of potassium persulfate and 100g of deionized water were weighed and stirred to dissolve evenly to prepare an oxidant solution. 40g of diatomaceous earth was added to the solution, and the diatomaceous earth after saturation adsorption was dried at 60℃ for 6h to obtain the oxidant.

[0026] (3) Preparation of absorbent

[0027] The absorbent is prepared by weighing 100g of sulfate ore slag powder, 1g of fly ash, 1g of steel slag powder and 1g of alkali slag powder in a mass ratio of 1:0.1:0.1:0.1.

[0028] (4) Preparation of multifunctional powder

[0029] According to the mass ratio of absorbent:catalyst:oxidant of 1:0.1:0.1, weigh 10g of catalyst prepared in step (1), 10g of oxidant prepared in step (2) and 100g of absorbent prepared in step (3), mix and ball mill to obtain a multifunctional powder with a particle size of 80-300 mesh.

[0030] (5) Performance evaluation of multifunctional powders

[0031] The multifunctional powder of the present invention has a denitrification efficiency of over 82% and a desulfurization efficiency of nearly 100% within the range of 80-300℃, and a CO removal efficiency of over 84%.

[0032] Example 2:

[0033] (1) Preparation of catalyst

[0034] The catalyst was obtained by weighing 100g of rare earth La and 10g of transition metal oxide (a mixture of Fe2O3, MnO2 and CuO with a mass ratio of 1:1:1) and mixing them thoroughly, according to the mass ratio of light rare earth mineral metal to transition metal oxide of 1:0.1.

[0035] (2) Preparation of oxidant

[0036] According to the mass ratio of deionized water: hexaamminecobalt trichloride: potassium persulfate of 1:0.05:0.05; and the mass ratio of diatomaceous earth: oxidant solution of 1:2.5, 5g of hexaamminecobalt trichloride, 5g of potassium persulfate and 100g of deionized water were weighed and stirred to dissolve evenly to prepare an oxidant solution. 40g of diatomaceous earth was added to the solution, and the diatomaceous earth after saturation adsorption was dried at 60℃ for 6h to obtain the oxidant.

[0037] (3) Preparation of absorbent

[0038] The absorbent is prepared by weighing 100g of sulfate ore slag powder, 1g of fly ash, 1g of steel slag powder and 1g of alkali slag powder in a mass ratio of 1:0.1:0.1:0.1.

[0039] (4) Preparation of multifunctional powder

[0040] According to the mass ratio of absorbent:catalyst:oxidant of 1:0.1:0.1, weigh 10g of catalyst prepared in step (1), 10g of oxidant prepared in step (2) and 100g of absorbent prepared in step (3), mix and ball mill to obtain a multifunctional powder with a particle size of 80-300 mesh.

[0041] (5) Performance evaluation of multifunctional powders

[0042] The multifunctional powder of the present invention has a denitrification efficiency of over 85% and a desulfurization efficiency of nearly 100% within the range of 80-300℃, and a CO removal efficiency of over 87%.

[0043] Example 3:

[0044] (1) Preparation of catalyst

[0045] The catalyst was obtained by weighing 10g of rare earth La and 100g of transition metal oxide (a mixture of Fe2O3, MnO2 and CuO with a mass ratio of 1:1:1) according to the mass ratio of light rare earth mineral metal to transition metal oxide of 1:10 and mixing them evenly.

[0046] (2) Preparation of oxidant

[0047] According to the mass ratio of deionized water: hexaamminecobalt trichloride: potassium persulfate 1:0.1:0.1; and the mass ratio of diatomaceous earth: oxidant solution 1:2.5, 10g of hexaamminecobalt trichloride, 10g of potassium persulfate and 100g of deionized water were weighed and stirred to dissolve evenly to prepare an oxidant solution. 40g of diatomaceous earth was added to the solution, and the diatomaceous earth after saturation adsorption was dried at 60℃ for 6h to obtain the oxidant.

[0048] (3) Preparation of absorbent

[0049] The absorbent is prepared by weighing 10g of sulfate ore slag powder, 100g of fly ash, 100g of steel slag powder and 100g of alkali slag powder in a mass ratio of 1:10:10:10.

[0050] (4) Preparation of multifunctional powder

[0051] According to the mass ratio of absorbent:catalyst:oxidant of 1:0.2:0.2, weigh 20g of catalyst prepared in step (1), 20g of oxidant prepared in step (2) and 100g of absorbent prepared in step (3), mix and ball mill to obtain a multifunctional powder with a particle size of 80-300 mesh.

[0052] (5) Performance evaluation of multifunctional powders

[0053] The multifunctional powder of this invention has a denitrification efficiency of over 90%, a desulfurization efficiency of nearly 100%, and a CO removal efficiency of over 90% within the temperature range of 80-300℃.

[0054] Example 4:

[0055] (1) Preparation of catalyst

[0056] The catalyst was obtained by weighing 10g of rare earth Ce and 100g of transition metal oxide (a mixture of Fe2O3, MnO2 and CuO in a mass ratio of 1:1:1) according to the mass ratio of light rare earth mineral metal to transition metal oxide of 1:10 and mixing them evenly.

[0057] (2) Preparation of oxidant

[0058] According to the mass ratio of deionized water: hexaamminecobalt trichloride: potassium persulfate 1:0.1:0.1; and the mass ratio of diatomaceous earth: oxidant solution 1:2.5, 10g of hexaamminecobalt trichloride, 10g of potassium persulfate and 100g of deionized water were weighed and stirred to dissolve evenly to prepare an oxidant solution. 40g of diatomaceous earth was added to the solution, and the diatomaceous earth after saturation adsorption was dried at 80℃ for 12h to obtain the oxidant.

[0059] (3) Preparation of absorbent

[0060] The absorbent is prepared by weighing 10g of sulfate ore slag powder, 100g of fly ash, 100g of steel slag powder and 100g of alkali slag powder in a mass ratio of 1:10:10:10.

[0061] (4) Preparation of multifunctional powder

[0062] According to the mass ratio of absorbent:catalyst:oxidant of 1:0.2:0.2, weigh 20g of catalyst prepared in step (1), 20g of oxidant prepared in step (2) and 100g of absorbent prepared in step (3), mix and ball mill to obtain a multifunctional powder with a particle size of 80-300 mesh. (5) Performance evaluation of multifunctional powder

[0063] The multifunctional powder of the present invention has a denitrification efficiency of over 89%, a desulfurization efficiency of nearly 100%, and a CO removal efficiency of over 88% within the range of 80-300℃.

Claims

1. A method for purifying NO x A multifunctional powder containing SO2 and CO, characterized in that... This multifunctional powder comprises three parts: an absorbent, a catalyst, and an oxidant, with a mass ratio of absorbent:catalyst:oxidant of 1:(0.1~0.2):(0.1~0.2). The catalyst is composed of transition metal oxides and light rare earth mineral metals; the oxidant is prepared by drying diatomaceous earth after saturating and adsorbing a strong oxidant solution; the absorbent is a composite absorbent composed of fly ash, steel slag powder, alkali slag and sulfate ore slag, wherein the mass ratio of sulfate ore slag powder, fly ash, steel slag powder and alkali slag powder is 1:(0.1~10):(0.1~10):(0.1~10); The method for preparing the oxidant is to stir and dissolve hexaamminecobalt trichloride, potassium persulfate and deionized water to obtain an oxidant solution, add diatomaceous earth to the solution, and dry the diatomaceous earth after saturation adsorption at 60-80 ℃ for 6-12 h to obtain the oxidant. The light rare earth mineral metal is at least one of La or Ce; the transition metal oxide is at least one of CoO, SnO2, Fe2O3, CuO, MnO2, or ZnO, and the mass ratio of the light rare earth mineral metal to the transition metal oxide is 1:(0.1~10); In the preparation method of the oxidant, the mass ratio of deionized water: hexaamminecobalt trichloride: potassium persulfate is 1:(0.05~0.1):(0.05~0.1); The mass ratio of diatomaceous earth to oxidant solution is 1:1~5.

2. The NO purification method according to claim 1 x A multifunctional powder containing SO2 and CO, characterized in that... The transition metal oxide in the catalyst is three of the following: CoO, SnO2, Fe2O3, CuO, MnO2, or ZnO.

3. A method for purifying NO according to claim 1 x A method for preparing a multifunctional powder containing SO2 and CO, characterized in that, This method involves mixing and ball-milling a catalyst, oxidant, and absorbent to produce a multifunctional powder with a particle size of 80-300 mesh.

4. A method for utilizing the multifunctional powder as described in claim 1 in the NO removal of coal-fired flue gas. x Application of synergistic governance of SO2 and CO.

5. The application according to claim 4, wherein the specific steps are as follows: In a flue gas area at 80-300℃, a multifunctional powder is sprayed in. Under the convective impact of the flue gas, the multifunctional powder is dispersed and fully mixed with the flue gas, where CO is oxidized to CO2 and NO... x SO2 is catalyzed and adsorbed, generating harmless sulfates, nitrates, sulfites, or nitrites, thereby reducing NO in coal-fired flue gas. x Coordinated governance of SO2 and CO.

6. The application according to claim 5, characterized in that... The mass ratio of the injected bifunctional powder to the mass of the flue gas is 1:0.1~2.

7. The application according to claim 5, characterized in that... The flue gas velocity is 1~7m / s.