CN113332954B - A kind of sintering flue gas denitrification adsorbent and its preparation method and application - Google Patents

Abstract

The invention provides a sintering flue gas denitration adsorbent and a preparation method and application thereof. In the present invention, a predetermined amount of blue charcoal and ferric nitrate are added into distilled water, fully stirred, and then filtered and dried to obtain an initial product; and then the obtained initial product is placed in a microwave field to react at a predetermined microwave power and heating temperature. At a predetermined time, a sintered flue gas denitration adsorbent was prepared. Through the above method, the present invention can use blue carbon as a carrier and support iron oxide on its surface, thereby preparing a denitration adsorbent with good stability, high strength, high denitration rate and low cost; the denitration adsorbent can not only be used for sintering In the process of flue gas denitrification, the adsorbed material can also be sent to the blast furnace to replace part of the coal injection, thereby realizing the multiple utilization of resources; and the preparation method provided by the invention is simple in process, easy to control, cheap and easy to obtain raw materials, and has the advantages of relatively low cost and low cost. high application value.

Description

A kind of sintering flue gas denitrification adsorbent and its preparation method and application

technical field

The invention relates to the technical field of preparation and application of gas adsorption materials, in particular to a sintered flue gas denitration adsorbent and a preparation method and application thereof.

Background technique

In the iron and steel industry, sintering flue gas emissions account for about 40% of the entire iron and steel industry flue gas emissions, and sintering flue gas contains a lot of fine dust, sulfur oxides, nitrogen oxides, dioxins and other pollutants, especially Nitrogen oxides have a serious impact on people's living environment. At the same time, the Ministry of Environmental Protection has issued and revised the document "Emission Standards for Air Pollutants in Iron and Steel Sintering and Pelletizing Industries", which has put forward more stringent requirements for enterprise flue gas emissions. How to reduce the emission of nitrogen oxides in sintering flue gas is a problem that the majority of metallurgical workers have been trying to solve.

At present, the most important method for denitrification of sintering flue gas in China is the NO _X treatment method. However, the removal of NO _X is quite difficult, mainly because the main component of NO _X in the flue gas is relatively stable NO. At present, the method of purifying and treating NO in flue gas can be divided into dry method and wet method according to the treatment process. Among them, dry methods mainly include: adsorption method, non-catalytic reduction method, plasma method, catalytic reduction method, etc.; wet methods mainly include: oxidation absorption, complex absorption, alkali absorption, liquid-phase reduction absorption, acid absorption, microbial method, etc. Among the above methods, the adsorption method has been widely used due to its advantages of simple process and good denitration performance, and the actual effect of the adsorption method is closely related to the corresponding adsorption material. Therefore, how to develop adsorption materials with excellent denitration effect has become the current research focus.

Patent publication number CN106563482A provides a preparation method of low-temperature denitration nitrogen-enriched porous carbon material. The patent uses raw coal and blue carbon particles as the main body, binder and deionized water as the guest, and obtains a porous carbon material through mixing, molding, carbonization and steam activation. Finally, it is oxidized by mixed acid and reduced by ferrous acetate. A nitrogen-rich porous carbon material with high denitration efficiency at low temperature is formed. However, this method is not only complicated in process, but also the denitrification rate of the prepared porous carbon material at different temperatures can only reach more than 65%, which is difficult to meet the needs of actual production and application.

In view of this, it is necessary to improve the existing denitration adsorbent and its preparation method, and use a simpler process to prepare a sintered flue gas denitration adsorbent with high denitration rate to solve the above problems.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects of the prior art, the object of the present invention is to provide a sintering flue gas denitration adsorbent and its preparation method and application. By using blue carbon as a carrier and supporting iron oxides on its surface, a denitration adsorbent with good stability, high strength, high denitration rate and low cost is prepared; the denitration adsorbent can not only be used for flue gas denitrification in the sintering process, The resulting material can also be sent to the blast furnace to replace part of the coal injection to realize the multiple utilization of resources.

In order to achieve the above purpose, the present invention provides a preparation method of a sintered flue gas denitration adsorbent, comprising the following steps:

S1, a predetermined amount of blue charcoal and ferric nitrate are added to distilled water, filter after fully stirring, and then dry for a certain time to make the blue charcoal water content between 10%～20%, obtain initial product;

S2. The initial product obtained in step S1 is placed in a microwave field, and reacted for a predetermined time under a predetermined microwave power and a heating temperature to obtain a sintered flue gas denitration adsorbent.

As a further improvement of the present invention, in step S1, the liquid-solid ratio of the distilled water and the blue charcoal is (5～15): 1mL/g.

As a further improvement of the present invention, in step S1, the liquid-solid ratio of the distilled water and the ferric nitrate is (25～35): 1mL/g.

As a further improvement of the present invention, in step S1, the stirring process is carried out at room temperature, and the stirring time is 1-3 hours.

As a further improvement of the present invention, in step S2, the microwave power is 600-800W, and the heating temperature is 600-800°C.

As a further improvement of the present invention, in step S2, the predetermined reaction time is 15-35 minutes.

In order to achieve the above object, the present invention also provides a sintered flue gas denitration adsorbent prepared according to any one of the above technical solutions.

As a further improvement of the present invention, the specific surface area of the sintered flue gas denitration adsorbent is 790-820 m ² /g, the compressive strength is 380-430 N/cm ² , and the NO _X conversion rate is greater than 90%.

To achieve the above object, the present invention also provides the application of the sintering flue gas denitrification adsorbent in the field of sintering flue gas denitrification.

As a further improvement of the present invention, the sintering flue gas denitration adsorbent is used to replace the blast furnace injection of pulverized coal after adsorbing the sintering flue gas.

The beneficial effects of the present invention are:

(1) The present invention uses blue carbon as a carrier, and by blending it with ferric nitrate and heating it by microwave, so as to uniformly load iron oxides on the surface of blue carbon with a simple and efficient process, and use it as sintering flue gas denitrification adsorption. agent. Based on the above preparation process, the iron oxide-loaded blue carbon prepared by the present invention has high specific surface area, compressive strength and NO _X conversion rate, can be used as an adsorbent for sintering flue gas denitrification, and has good stability, It has the advantages of high strength, high denitrification rate and low cost. At the same time, the denitration adsorbent prepared by the invention can not only be used for flue gas denitrification in the sintering process, but the adsorbed material can also be sent to the blast furnace to replace part of the coal injection, so as to realize the multiple utilization of resources and have a good application prospect.

(2) Blue charcoal is the product of coal pyrolysis at lower temperature, but it has not been pyrolyzed completely, and its specific surface area is smaller than that of activated carbon, and it is discarded because it is not effectively utilized, resulting in a serious waste of resources. Compared with activated carbon, the present invention can effectively reduce the cost and improve the utilization rate of resources by using the blue carbon as the carrier. On this basis, by loading iron oxides on the surface of blue carbon, the present invention can not only utilize more hydrogen and oxygen inside the blue carbon that is not completely pyrolyzed and its rich pores and surface structure to ensure that iron oxides are in the blue carbon It can also effectively improve the strength and adsorption performance of blue carbon by using the supported iron oxides, so as to achieve efficient adsorption of nitrogen oxides in sintering flue gas and achieve excellent denitration effect. In addition, the denitration adsorbent prepared by loading iron oxides on blue carbon in the present invention can also be sent to the blast furnace to replace part of the coal injection after the adsorption is completed, which not only realizes the multiple utilization of resources, but also completes the adsorption of the adsorbent. Harmless treatment has good economic and environmental benefits.

(3) In the present invention, by controlling the water content of the dried blue carbon to be 10% to 20%, and then placing it in a microwave field, not only can the pore structure of the blue carbon be enriched by the catalytic pore formation of the microwave itself, but also the pore structure of the blue carbon can be enriched. The water contained in the blue charcoal loaded with ferric nitrate rapidly absorbs waves and heats up under the microwave field and generates water vapor, which further promotes the formation of macropores in the blue charcoal, and plays a dual activation effect of the synergistic effect of microwave activation and water vapor activation, thereby The adsorbent prepared by the present invention has a higher specific surface area than the conventional adsorbent, so as to realize the efficient adsorption of nitrogen oxides in the sintering flue gas.

(4) The present invention can effectively control the loading of iron oxides and the pore structure of the adsorbent by controlling the liquid-solid ratio of distilled water, blue carbon and ferric nitrate, and further controlling the parameters of the microwave heating process. Therefore, the prepared sintered flue gas denitrification adsorbent has high strength, good stability and excellent adsorption. In addition, the preparation method provided by the present invention is simple in process, easy to control, cheap and easy to obtain raw materials, does not require conventional pickling and other treatment methods in the preparation process, and will not cause secondary pollution, and the prepared product is used in sintering flue gas denitrification and sintering. Blast furnaces have great potential in replacing part of pulverized coal injection, and have high application value.

Detailed ways

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to specific embodiments.

In addition, it should be noted that the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or apparatus comprising a series of elements includes not only those elements, but also Also included are other elements not expressly listed or inherent to such a process, method, article or apparatus.

The invention provides a preparation method of a sintered flue gas denitration adsorbent, comprising the following steps:

S1, a predetermined amount of blue charcoal and ferric nitrate are added to distilled water, filter after fully stirring, and then dry for a certain time to make the blue charcoal water content between 10%～20%, obtain initial product;

S2. The initial product obtained in step S1 is placed in a microwave field, and reacted for a predetermined time under a predetermined microwave power and a heating temperature to obtain a sintered flue gas denitration adsorbent.

As a further improvement of the present invention, in step S1, the liquid-solid ratio of the distilled water and the blue charcoal is (5～15): 1 mL/g; the liquid-solid ratio of the distilled water and the ferric nitrate is (25 ~35): 1 mL/g; The stirring process is carried out at room temperature, and the stirring time is 1 to 3 h.

In step S2, the microwave power is 600-800W, the heating temperature is 600-800°C; and the predetermined reaction time is 15-35 minutes.

The present invention also provides a sintering flue gas denitration adsorbent prepared according to any one of the above technical solutions.

The specific surface area of the sintered flue gas denitration adsorbent is 790-820 m ² /g, the compressive strength is 380-430 N/cm ² , and the NO _X conversion rate is greater than 90%.

The invention also provides the application of the sintering flue gas denitration adsorbent in the field of sintering flue gas denitration.

The sintering flue gas denitration adsorbent is used to replace the blast furnace blowing pulverized coal after adsorbing the sintering flue gas.

The sintered flue gas denitrification adsorbent provided by the present invention and its preparation method and application will be described below with reference to specific embodiments.

Example 1

The present embodiment provides a preparation method of a sintered flue gas denitration adsorbent, comprising the following steps:

S1. Add blue charcoal and ferric nitrate into distilled water, control the liquid-solid ratio of distilled water and blue charcoal to be 5:1 mL/g, and the liquid-solid ratio of distilled water to ferric nitrate to be 25:1 mL/g. After stirring for 1 h at room temperature, the product was filtered and separated and then dried in a constant temperature drying oven to obtain the initial product;

S2. The initial product obtained in step S1 is placed in a microwave field, and reacted for 15 min under the conditions of microwave power 600W and heating temperature 600°C to obtain iron oxide-loaded blue carbon, which is used as sintering flue gas for denitration adsorption agent.

Examples 2-3 and Comparative Examples 1-4

Embodiments 2 to 3 and comparative examples 1 to 4 respectively provide a preparation method of a sintered flue gas denitration adsorbent. Compared with embodiment 1, the difference is that the process parameters in steps S1 and S2 are changed. The corresponding process parameters of Examples 2 to 3 and Comparative Examples 1 to 4 are shown in Table 1, and the remaining steps are the same as those of Example 1, and will not be repeated here.

Table 1 Process parameters of Examples 2-3 and Comparative Examples 1-4

In order to compare the performance of the sintered flue gas denitrification adsorbents prepared under different process parameters, the specific surface area, compressive strength and NO _X conversion rate of the sintered flue gas denitration adsorbents prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were tested. The results are shown in Table 2.

Table 2 Detection data of the sintered flue gas denitration adsorbents prepared in Examples 1-3 and Comparative Examples 1-4

It can be seen from Table 2 that when the microwave power is high and the microwave heating time is long, the inner pore structure of the adsorbent material will collapse. Although its compressive strength is high, the nitrogen oxide conversion rate is low; when the microwave power is low and the When the microwave heating time is short, the adsorption material obtained has a lower specific surface area and lower denitrification capacity. Only when the proportion of blue carbon and ferric nitrate is appropriate and the microwave power and heating time are appropriate, the prepared adsorbent has a good denitration ability.

Based on the above analysis, the present invention controls the liquid-solid ratio of distilled water, blue charcoal, and ferric nitrate, and further controls the parameters of the microwave heating process, so that the loading of iron oxides and the degree of combination thereof with blue charcoal can be controlled. Effective regulation, so that the prepared sintered flue gas denitrification adsorbent has a large specific surface area, high strength and excellent adsorption, and achieves a high denitrification rate to meet the needs of practical applications. At the same time, the sintering flue gas denitrification adsorbent prepared in each embodiment of the present invention can not only be used for efficient denitrification of sintering flue gas, but also can be sent to the blast furnace as a substitute for blast furnace injection coal after adsorbing nitrogen oxides. The harmless treatment of the adsorbent is completed and the resources are reused many times, which has a good application prospect.

In summary, the present invention provides a sintered flue gas denitration adsorbent and a preparation method and application thereof. In the present invention, a predetermined amount of blue charcoal and ferric nitrate are added into distilled water, and the initial product is obtained by filtration and drying after full stirring; and then the obtained initial product is placed in a microwave field to react under a predetermined microwave power and heating temperature. At a predetermined time, a sintered flue gas denitration adsorbent was prepared. Through the above method, the present invention can use blue carbon as a carrier and support iron oxide on its surface, thereby preparing a denitration adsorbent with good stability, high strength, high denitration rate and low cost; the denitration adsorbent can not only be used for sintering In the process of flue gas denitrification, the adsorbed material can also be sent to the blast furnace to replace part of the coal injection, thereby realizing the multiple utilization of resources; and the preparation method provided by the invention is simple in process, easy to control, cheap and easy to obtain raw materials, and has the advantages of relatively low cost and low cost. high application value.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced. Without departing from the spirit and scope of the technical solutions of the present invention.

Claims (6)

1. A preparation method of a sintering flue gas denitration adsorbent is characterized by comprising the following steps:

s1, adding a predetermined amount of semi-coke and ferric nitrate into distilled water, fully stirring, filtering, and drying for a certain time to ensure that the water content of the semi-coke is between 10 and 20 percent to obtain a primary product; the liquid-solid ratio of the distilled water to the semi-coke is (5-15) to 1 mL/g; the liquid-solid ratio of the distilled water to the ferric nitrate is (25-35) to 1 mL/g;

s2, placing the primary product obtained in the step S1 in a microwave field, and reacting for a preset time under a preset microwave power and heating temperature to obtain a sintered flue gas denitration adsorbent; the microwave power is 600-800W, and the heating temperature is 600-800 ℃;

the specific surface area of the sintering flue gas denitration adsorbent is 790-820 m²(g) the compressive strength is 380-430N/cm²，NO_XThe conversion is greater than 90%.

2. The preparation method of the sintered flue gas denitration adsorbent according to claim 1, characterized by comprising the following steps: in step S1, the stirring process is performed at room temperature for 1-3 hours.

3. The preparation method of the sintered flue gas denitration adsorbent according to claim 1, characterized by comprising the following steps: in step S2, the reaction time is 15-35 min.

4. The sintered flue gas denitration adsorbent is characterized in that: the sintered flue gas denitration adsorbent is prepared by the preparation method of any one of claims 1 to 3.

5. The application of the sintered flue gas denitration adsorbent prepared by the preparation method of any one of claims 1 to 3 or the sintered flue gas denitration adsorbent of claim 4 is characterized in that: the sintering flue gas denitration adsorbent is applied to the field of sintering flue gas denitration.

6. The application of the sintered flue gas denitration adsorbent according to claim 5, wherein: the sintering flue gas denitration adsorbent is used for replacing blast furnace injection coal powder after adsorbing the sintering flue gas.