Method for preparing efficient flue gas desulfurization and denitrification adsorbent through carbon material modification

Abstract

The invention provides a method for preparing an efficient flue gas desulfurization and denitrification adsorbent by modifying a carbon material, which comprises the following steps: selecting a carbon material raw material, crushing, screening the crushed carbon material raw material, and drying the screened carbon material raw material; preparing a composite modifier solution from a nitric acid solution and a ferrous sulfate solution, and uniformly stirring; mixing the composite modifier solution with a carbon material raw material, and adding titanium dioxide at the same time to obtain a mixed material; uniformly stirring the mixed material, and carrying out modification reaction under preset modification reaction conditions; after the modification reaction is completed, separating a reaction mixture to obtain a solid product and waste liquid; recovering the modifier from the solid product; and carrying out drying and low-temperature roasting on the solid product to obtain the dried flue gas desulfurization and denitrification adsorbent. The method is convenient to operate, high in modification efficiency, low in cost and good in environmental protection property, and the prepared flue gas desulfurization and denitrification adsorbent is excellent in performance and has important industrial application value and environmental benefits.

Description

Technical Field

[0001] This invention belongs to the field of adsorbent preparation technology, specifically relating to a method for preparing a high-efficiency flue gas desulfurization and denitrification adsorbent by modifying carbon materials. Background Technology

[0002] SO2 and NO contained in industrial flue gas x Pollutants such as SO2 and NOx are among the main causes of environmental problems such as acid rain and smog, seriously endangering the ecological environment and human health. With increasingly stringent environmental standards, flue gas desulfurization and denitrification have become essential steps for industrial enterprises to meet emission standards. Carbon materials, with their large specific surface area, well-developed pore structure, excellent adsorption performance, and strong chemical stability, are ideal raw materials for preparing flue gas desulfurization and denitrification adsorbents, capable of effectively treating SO2 and NOx. x The efficient adsorption and conversion of carbon materials drive the upgrading of carbon materials from basic applications to high-value applications.

[0003] Currently, the preparation of carbon-based desulfurization and denitrification adsorbents mostly employs single modification methods, which suffer from problems such as low adsorption capacity, poor simultaneous desulfurization and denitrification efficiency, poor adsorbent regeneration performance, and short service life. Furthermore, the modification process involves low modifier utilization, high energy consumption, and the potential for secondary pollution from waste liquid and waste gas, limiting their large-scale industrial application. In addition, existing adsorbents are difficult to adapt to complex flue gas components (such as dust-containing and humid flue gas), and are prone to rapid adsorption saturation and rapid performance degradation, failing to meet the requirements for deep desulfurization and denitrification of industrial flue gas (SO2 removal rate ≥98%, NO...). x The requirement is a removal rate of ≥95%.

[0004] Chinese patent document CN 103232036 A discloses a method for preparing desulfurization and denitrification activated carbon. The method includes: a) impregnating activated carbon in an alkaline solution at a constant temperature; b) oxidizing and drying the impregnated activated carbon, followed by spray treatment to obtain desulfurization and denitrification activated carbon. The main drawbacks of the technology involved in Chinese patent document CN 103232036 A are: ① It only uses a single alkaline solution for modification and does not introduce catalytic components, resulting in limited improvement in the pore structure and active sites of the carbon material, making it difficult to meet the needs of deep industrial treatment for desulfurization and denitrification; ② The alkaline solution is not recovered, and there is no targeted washing process, which easily causes secondary pollution and affects product stability; ③ There is no precise parameter control and regeneration process, resulting in uneven product quality and high usage costs.

[0005] To address the aforementioned issues, it is necessary to propose a method for preparing high-efficiency flue gas desulfurization and denitrification adsorbents through the modification of carbon materials, which is both rationally designed and effectively solves these problems. Summary of the Invention

[0006] The present invention aims to at least solve one of the technical problems existing in the prior art, and provides a method for preparing a high-efficiency flue gas desulfurization and denitrification adsorbent by modifying carbon materials.

[0007] This invention provides a method for preparing a high-efficiency flue gas desulfurization and denitrification adsorbent by modifying carbon materials, the method comprising: Select carbon material raw materials, crush them, sieve the crushed carbon material raw materials, and then dry the sieved carbon material raw materials; A composite modifier solution was prepared using nitric acid solution and ferrous sulfate solution, and then stirred until homogeneous. The composite modifier solution is mixed with carbon material raw materials, and titanium dioxide is added at the same time to obtain a mixed material; The mixed materials are stirred evenly and then subjected to a modification reaction under the preset modification reaction conditions; After the modification reaction is completed, the reaction mixture is separated to separate the solid product and waste liquid; Recovery of modifiers from solid products; The solid product is dried and calcined at low temperature to obtain a dry flue gas desulfurization and denitrification adsorbent.

[0008] Optionally, a composite modifier solution can be prepared using nitric acid solution and ferrous sulfate solution, including: A composite modifier solution was prepared by mixing 0.6 mol / L to 1.2 mol / L nitric acid solution and 0.3 mol / L to 0.5 mol / L ferrous sulfate solution at a volume ratio of 2:1.

[0009] Optionally, the composite modifier solution is mixed with the carbon material raw material, and titanium dioxide is added simultaneously to obtain a mixed material, including: The composite modifier solution and the carbon material raw material are mixed at a mass ratio of (4-6):1, and titanium dioxide is added at the same time, wherein the mass of titanium dioxide is 5% to 8% of the mass of the carbon material raw material.

[0010] Optionally, the mixture is stirred until homogeneous, including: The mixture is stirred evenly by a combination of ultrasonic vibration and mechanical stirring, wherein the ultrasonic power is controlled at 300W~350W and the stirring speed is 70r / min~80r / min.

[0011] Optionally, the modification reaction occurs under preset modification reaction conditions, including: The reaction temperature was controlled by a water bath at 55℃~65℃ with a temperature control accuracy of ±2℃. The pH value and temperature of the reaction system were monitored in real time, and the reaction time was controlled at 40 min~70 min to complete the modification reaction.

[0012] Optionally, the modifier may be recovered from the solid product, including: The separated solid products are subjected to pressure filtration and dehydration to reduce the water content of the solid products, while the residual modifiers in the solid products are squeezed out for recycling.

[0013] Optionally, the recovery of modifiers from solid products also includes: The solid product after pressure filtration and dehydration is washed with deionized water until the pH value of the washing solution reaches 6.5~7.5; Collect washing wastewater, regenerate the wastewater, and recover the modifiers contained therein.

[0014] Optionally, the solid product may be dried and calcined at a low temperature, including: The solid product was dried using a hot air circulation drying method, with the drying temperature controlled at 115℃~120℃ and the drying time at 40min~50min. The dried solid product is subjected to low-temperature calcination activation treatment, wherein the calcination temperature is controlled at 250℃~280℃ and the calcination time is 1.5h~2h.

[0015] Optionally, after the adsorbent becomes saturated, the method further includes: The hot air purging regeneration method is adopted, with the purging temperature controlled at 180℃~200℃ and the purging time at 30min~40min, to purge the dry flue gas desulfurization and denitrification adsorbent and regenerate the adsorbent.

[0016] Optionally, the method further includes: The quality of the dried flue gas desulfurization and denitrification adsorbent and the regenerated adsorbent were tested to ensure that their adsorption capacity for SO2 was ≥200mg / g and their adsorption capacity for NO was ≥200mg / g. x Adsorption capacity ≥150mg / g, SO2 removal rate ≥98%, NO x Removal rate ≥ 95%.

[0017] The present invention provides a method for preparing high-efficiency flue gas desulfurization and denitrification adsorbents by modifying carbon materials. This method offers a highly efficient, energy-saving, environmentally friendly, and convenient approach to preparing flue gas desulfurization and denitrification adsorbents, improving the carbon materials' ability to adsorb SO2 and NO. x It improves the adsorption capacity and simultaneous removal efficiency, enhances the regeneration performance of adsorbents, extends service life, reduces modification and usage costs, reduces environmental pollution, meets the needs of deep desulfurization and denitrification of industrial flue gas, promotes the high-value application of carbon materials, and has important industrial application value and environmental benefits. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of a method for preparing a high-efficiency flue gas desulfurization and denitrification adsorbent by modifying carbon materials according to an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] This invention addresses the problems existing in current technologies for modifying carbon materials to prepare flue gas desulfurization and denitrification adsorbents, such as low modification efficiency, small adsorption capacity, poor simultaneous desulfurization and denitrification efficiency, poor adsorbent regeneration performance, low modifier utilization rate, environmental pollution from modified wastewater, and high energy consumption. Figure 1 As shown, this invention proposes a method S100 for preparing a high-efficiency flue gas desulfurization and denitrification adsorbent by modifying carbon materials, the method comprising: S110. Select carbon material raw materials, crush them, sieve the crushed carbon material raw materials, and then dry the sieved carbon material raw materials.

[0021] Specifically, activated carbon, biochar, and other carbonaceous raw materials are selected. These raw materials are first pulverized to a particle size ≤0.08mm to increase their specific surface area and porosity, thereby improving the subsequent modification effect. The pulverized raw materials are then sieved with a sieving efficiency ≥99% to remove impurities and materials with unqualified particle sizes. The sieved raw materials are then dried at a controlled temperature of 105℃~115℃ until the moisture content is ≤4%, preventing moisture from affecting the modification reaction and adsorption performance.

[0022] In this embodiment, the carbon material raw material is precisely pretreated by pulverizing, sieving, and drying to ensure that the carbon material has uniform particle size and meets the moisture content requirements, thereby improving the modification effect and adsorption performance.

[0023] S120. Prepare a composite modifier solution using nitric acid solution and ferrous sulfate solution, and stir until homogeneous.

[0024] Specifically, a composite modifier solution is prepared by mixing a 0.6 mol / L to 1.2 mol / L nitric acid solution and a 0.3 mol / L to 0.5 mol / L ferrous sulfate solution at a volume ratio of 2:1. The composite modifier solution is stirred until completely dissolved to ensure uniform modifier concentration.

[0025] S130. The composite modifier solution is mixed with the carbon material raw material, and titanium dioxide is added at the same time to obtain a mixed material.

[0026] Specifically, the composite modifier solution is mixed with the carbon material raw material at a mass ratio of (4-6):1, and titanium dioxide is added simultaneously, wherein the mass of titanium dioxide is 5% to 8% of the mass of the carbon material raw material. The titanium dioxide needs to be pretreated by ultrasonic dispersion.

[0027] In this embodiment, the precise control method for the preparation and metering of the composite modifier, combined with the ultrasonic dispersion pretreatment of titanium dioxide, ensures that the concentration, ratio, and uniform mixing of the modifier and composite components are maintained, avoiding waste of modifier and titanium dioxide, improving the modification effect and raw material utilization rate, and enhancing the desulfurization and denitrification performance of the adsorbent.

[0028] S140. Stir the mixed materials evenly and allow the modification reaction to occur under the preset modification reaction conditions.

[0029] Specifically, the mixture is stirred evenly using a combination of ultrasonic vibration and mechanical stirring. The ultrasonic power is controlled at 300W~350W, and the stirring speed is controlled at 70r / min~80r / min. Preferably, the ultrasonic power is controlled at 300W, and the stirring speed is controlled at 70r / min to ensure that the carbon material, modifier, and titanium dioxide are in full contact and mixed evenly.

[0030] A water bath temperature control method was adopted to control the reaction temperature at 55℃~65℃ with a temperature control accuracy of ±2℃. The pH value and temperature of the reaction system were monitored in real time, and the reaction time was controlled at 40 min~70 min to promote the rapid and complete modification reaction, increase the number of oxygen-containing functional groups on the surface of carbon materials, and optimize the pore structure.

[0031] In this embodiment, a modification reaction condition combining ultrasonic vibration and mechanical stirring is adopted, along with a precise temperature and pH control mechanism, to achieve rapid and complete modification reaction, increase the number of oxygen-containing functional groups on the surface of carbon materials, and optimize the pore structure.

[0032] S150. After the modification reaction is completed, the reaction mixture is separated to separate the solid product and waste liquid.

[0033] Specifically, after the modification reaction is completed, the reaction mixture is separated to separate solid products and waste liquid. The solid products are the modified carbon materials.

[0034] S160. Recover the modifier from the solid product.

[0035] Specifically, the separated solid products are subjected to pressure filtration and dehydration treatment to reduce the water content of the solid products (≤28%), while the residual modifier in the solid products is squeezed out and recycled to the modifier preparation stage.

[0036] The solid product after pressure filtration and dehydration is washed with deionized water until the pH value of the washing liquid reaches 6.5-7.5; the washing wastewater is collected and regenerated to recover the modifier, which is then recycled for the modification reaction, ensuring that the modifier recovery rate is ≥88%; the purified washing wastewater can be recycled for subsequent washing processes, ensuring that the water resource utilization rate is ≥92%, reducing water resource consumption and environmental pollution.

[0037] In this embodiment, the residual modifier recovery method combining solid-liquid separation and pressure filtration, combined with the regeneration treatment of washing wastewater, realizes the recycling of modifier and water resources, reduces costs and environmental pollution.

[0038] S170. The solid product is dried and calcined at low temperature to obtain a dry flue gas desulfurization and denitrification adsorbent.

[0039] Specifically, a hot air circulation drying method is used, controlling the drying temperature at 115℃~120℃ and the drying time at 40min~50min to dry the solid product until the moisture content is ≤4%. The dried solid product is then subjected to low-temperature calcination activation treatment, where the calcination temperature is controlled at 250℃~280℃ and the calcination time is controlled at 1.5h~2h to improve the pore structure stability and adsorption activity of the adsorbent, resulting in a dried flue gas desulfurization and denitrification adsorbent. Hot air circulation and calcination waste heat recovery are utilized, with a waste heat utilization rate ≥75%, reducing drying and calcination energy consumption. Preferably, the drying temperature is controlled at 115℃ and the drying time at 40min, while the calcination temperature is controlled at 250℃ and the calcination time at 1.5h.

[0040] In this embodiment, a hot air circulation drying and low-temperature calcination activation process is adopted, combined with waste heat recovery, to reduce energy consumption and improve the pore structure stability and adsorption activity of the adsorbent.

[0041] Optionally, after the adsorbent becomes saturated, the method further includes: The hot air purging regeneration method is adopted, with the purging temperature controlled at 180℃~200℃ and the purging time at 30min~40min, to purge the dry flue gas desulfurization and denitrification adsorbent and regenerate the adsorbent.

[0042] Specifically, after the adsorbent becomes saturated, it is regenerated by hot air purging, with the purging temperature controlled at 180℃ and the purging time at 30 minutes, to remove SO2 and NO adsorbed on the surface of the adsorbent. x Pollutants such as [unspecified pollutants] can be regenerated; the regenerated adsorbent can be recycled, with a regeneration cycle of ≥8 times, and the adsorption capacity after regeneration remains at more than 85% of the initial capacity, thus extending the adsorbent's service life and reducing usage costs.

[0043] Optionally, the method further includes: The quality of the dried flue gas desulfurization and denitrification adsorbent and the regenerated adsorbent were tested to ensure that their adsorption capacity for SO2 was ≥200mg / g and their adsorption capacity for NO was ≥200mg / g. x Adsorption capacity ≥150mg / g, SO2 removal rate ≥98%, NO x The removal rate is ≥95%, which meets the requirements of high-efficiency flue gas desulfurization and denitrification adsorbents; qualified products are collected and stored, and unqualified products are returned to the modification reaction stage for re-modification.

[0044] In addition, the entire process of the method for preparing high-efficiency flue gas desulfurization and denitrification adsorbent by modifying carbon materials is automated and controlled by an industrial-grade PLC. It displays and controls key parameters in each stage, such as carbon material pretreatment, modifier preparation, modification reaction, solid-liquid separation, washing and recovery, drying and calcination, and regeneration, in real time. It has functions such as parameter setting, fault alarm, data storage (≥5 years), and remote control. The modification parameters can be flexibly adjusted according to the flue gas composition and treatment requirements to ensure stable product quality.

[0045] The present invention relates to a method for preparing a high-efficiency flue gas desulfurization and denitrification adsorbent by modifying carbon materials. The flue gas desulfurization and denitrification adsorbent prepared using this method is effective against SO2 and NO. x The adsorption capacity is significantly improved, and the simultaneous removal efficiency is high, which can meet the requirements of deep desulfurization and denitrification of industrial flue gas. Compared with existing technologies, the modification reaction time is shortened by 70%~85%, the modification efficiency is significantly improved, and the energy consumption per unit product is reduced by more than 45%. The modifier recovery rate is ≥88%, and the water resource utilization rate is ≥92%, which effectively reduces the modification cost and reduces environmental pollution. The synergistic effect of ultrasonic stirring and mechanical stirring, combined with the precise dispersion and compounding of titanium dioxide, ensures stable modification effect and good product quality consistency. After the adsorbent is saturated, it is regenerated by hot air purging. The adsorbent has excellent regeneration performance and can be recycled multiple times, further reducing the cost of use. It is easy to operate and can realize fully automated operation, which is suitable for large-scale industrial applications. It promotes the upgrading of carbon materials from basic adsorption to high-value-added environmental protection adsorbents, which is of great significance to promoting the development of industrial flue gas treatment technology and the high-quality development of the carbon materials industry.

[0046] The following examples illustrate the specific process of the method for preparing high-efficiency flue gas desulfurization and denitrification adsorbents by modifying carbon materials according to the present invention.

[0047] Example 1 This embodiment provides a method for preparing a high-efficiency flue gas desulfurization and denitrification adsorbent by modifying carbon materials, specifically using coconut shell activated carbon as raw material. First, the coconut shell activated carbon raw material is pulverized to a particle size ≤0.1mm, sieved to remove impurities and unqualified particles, and then dried at 110℃. A composite modifier solution is prepared: 0.9mol / L nitric acid solution and 0.4mol / L ferrous sulfate solution are mixed at a volume ratio of 2:1 and stirred until homogeneous. The composite modifier solution is then mixed with the carbon material raw material at a mass ratio of 5:1, and titanium dioxide is added simultaneously, with the amount of titanium dioxide added being 6.5% of the mass of the carbon material raw material. The mixture is stirred uniformly using a combination of ultrasonic vibration and mechanical stirring, controlling the ultrasonic power at 325W and the stirring speed at 75r / min. A water bath temperature control method is used, controlling the reaction temperature at 60℃ with a temperature control accuracy of ±2℃. The pH value and temperature of the reaction system are monitored in real time, and the reaction time is controlled at 55min to complete the modification reaction. After the modification reaction is completed, the reaction mixture is separated to obtain solid products and waste liquid. The separated solid products are subjected to pressure filtration and dehydration to reduce the water content and simultaneously squeeze out the residual modifier. Then, the solid products are washed with deionized water until the pH of the washing liquid reaches 6.5-7.5. The washing wastewater is collected and regenerated to recover the modifier. The washed solid products are dried using hot air circulation drying at 118℃ for 45 minutes. The dried solid products are then subjected to low-temperature calcination activation treatment at 265℃ for 1.8 hours to obtain a dried flue gas desulfurization and denitrification adsorbent. Testing showed that the adsorbent obtained in this embodiment has an adsorption capacity of 215 mg / g for SO2 and an adsorption capacity of [missing information - likely NO2]. x The adsorption capacity was 162 mg / g, the SO2 removal rate was 98.5%, and the NO removal rate was... x The removal rate was 95.8%.

[0048] Example 2 The difference between this embodiment and Example 1 is that the concentration of nitric acid solution in the composite modifier is adjusted to 0.6 mol / L, while the concentration of ferrous sulfate solution remains unchanged at 0.4 mol / L. The remaining steps and parameters are identical to those in Example 1. Specifically: Coconut shell activated carbon is used as raw material, pulverized, sieved, and dried at 110℃. The composite modifier solution is prepared by mixing 0.6 mol / L nitric acid solution and 0.4 mol / L ferrous sulfate solution at a volume ratio of 2:1. The composite modifier solution is then mixed with carbon material at a mass ratio of 5:1, and 6.5% titanium dioxide is added. The mixture is thoroughly mixed under ultrasonic power of 325W and stirring speed of 75 r / min. The reaction is carried out in a 60℃ water bath for 55 min. Subsequently, the adsorbent is obtained through solid-liquid separation, pressure filtration dehydration, washing to a pH of 6.5~7.5, drying at 118℃ for 45 min, and calcination at 265℃ for 1.8 h. Compared to Example 1, this example only reduced the nitric acid concentration from 0.9 mol / L to 0.6 mol / L, while keeping all other parameters unchanged. The adsorbent obtained in this example was found to have an adsorption capacity of 178 mg / g for SO2 and [missing information - likely NO]. x The adsorption capacity was 135 mg / g, the SO2 removal rate was 94.2%, and the NO removal rate was... x The removal rate was 91.5%. The results indicate that reducing the nitric acid concentration decreases the number of oxygen-containing functional groups on the surface of the carbon material, weakens the loading capacity of the active components, and increases the removal rate of SO2 and NO. x The adsorption capacities decreased by approximately 17% and 17% respectively compared to Example 1.

[0049] Example 3 The difference between this embodiment and Example 1 is that the concentration of ferrous sulfate solution in the composite modifier is adjusted to 0.5 mol / L, while the concentration of nitric acid solution remains unchanged at 0.9 mol / L. The remaining steps and parameters are exactly the same as in Example 1. Specifically: Coconut shell activated carbon is used as raw material, pulverized, sieved, and dried at 110℃. The composite modifier solution is prepared by mixing 0.9 mol / L nitric acid solution and 0.5 mol / L ferrous sulfate solution at a volume ratio of 2:1. The composite modifier solution is mixed with carbon material at a mass ratio of 5:1, and 6.5% titanium dioxide is added. The mixture is then stirred evenly at an ultrasonic power of 325W and a stirring speed of 75 r / min. The reaction is carried out in a 60℃ water bath for 55 min. Subsequent treatment is the same as in Example 1. Compared with Example 1, this embodiment only increases the ferrous sulfate concentration from 0.4 mol / L to 0.5 mol / L, while keeping all other parameters unchanged. The adsorbent obtained in this embodiment has an adsorption capacity of 238 mg / g for SO2 and a capacity of [missing information - likely related to NO]. x The adsorption capacity was 181 mg / g, the SO2 removal rate was 99.1%, and the NO removal rate was... x The removal rate was 97.2%. The results indicate that increasing the ferrous sulfate concentration can increase the loading of the iron-active components and enhance the removal of SO2 and NO.x The catalytic oxidation ability of the adsorption capacity increases by about 11% and 12% compared to Example 1, respectively.

[0050] Example 4 The difference between this embodiment and Example 1 is that the modification reaction temperature is adjusted to 65℃, while the remaining steps and parameters are exactly the same as in Example 1. Specifically, coconut shell activated carbon is used as raw material, pulverized, sieved, and dried at 110℃. A composite modifier solution with a volume ratio of 0.9 mol / L nitric acid and 0.4 mol / L ferrous sulfate of 2:1 is prepared and mixed with the carbon material at a mass ratio of 5:1. 6.5% titanium dioxide is added, and the mixture is stirred evenly under ultrasonic power of 325W and stirring speed of 75 r / min. A water bath temperature control method is used to control the reaction temperature at 65℃ with a temperature control accuracy of ±2℃, and the reaction time is 55 min. Subsequent solid-liquid separation, pressure filtration dehydration, washing, drying, calcination, and other steps are the same as in Example 1. Compared with Example 1, this embodiment only increases the reaction temperature from 60℃ to 65℃, while all other parameters remain unchanged. The adsorbent obtained in this embodiment has an adsorption capacity of 229 mg / g for SO2 and NO2. x The adsorption capacity was 173 mg / g, the SO2 removal rate was 98.9%, and the NO removal rate was... x The removal rate was 96.5%. The results indicate that appropriately increasing the reaction temperature is beneficial to the modification reaction, reducing SO2 and NO removal. x The adsorption capacities were increased by approximately 6.5% and 6.8% compared to Example 1, respectively.

[0051] Example 5 The difference between this embodiment and Example 1 is that the modification reaction time is adjusted to 40 min, while the remaining steps and parameters are exactly the same as in Example 1. Specifically, coconut shell activated carbon is used as raw material, pulverized, sieved, and dried at 110℃. A composite modifier solution with a volume ratio of 0.9 mol / L nitric acid and 0.4 mol / L ferrous sulfate of 2:1 is prepared and mixed with the carbon material at a mass ratio of 5:1. 6.5% titanium dioxide is added, and the mixture is stirred evenly under ultrasonic power of 325W and stirring speed of 75 r / min. The reaction is carried out in a 60℃ water bath for 40 min. Subsequent treatment is the same as in Example 1. Compared with Example 1, this embodiment only shortens the reaction time from 55 min to 40 min, while all other parameters remain unchanged. The adsorbent obtained in this embodiment has an adsorption capacity of 192 mg / g for SO2 and NO2. x The adsorption capacity is 145 mg / g, the SO2 removal rate is 95.8%, and the NO removal rate is... x The removal rate was 93.1%. The results indicate that insufficient reaction time leads to incomplete modification and uneven loading of the active components, resulting in the removal of SO2 and NO. x The adsorption capacities decreased by approximately 11% and 10% compared to Example 1, respectively.

[0052] Comparative example: Compared with Example 1, this comparative example does not use the preferred range of the present invention for several key process parameters, in order to illustrate the technical advantages of the present invention. Specifically, coconut shell activated carbon is used as raw material. First, the coconut shell activated carbon raw material is crushed to a particle size ≤0.1mm, sieved to remove impurities and unqualified particle size materials, and then dried at 110℃. A composite modifier solution is prepared: 0.3mol / L nitric acid solution and 0.2mol / L ferrous sulfate solution are mixed at a volume ratio of 2:1 (concentration lower than the range of 0.6mol / L~1.2mol / L and 0.3mol / L~0.5mol / L as defined in claim 2), and stirred evenly. The composite modifier solution is mixed with the carbon material raw material at a mass ratio of 2:1 (mass ratio lower than the range of 4-6:1 as defined in claim 3), and titanium dioxide is added simultaneously. The amount of titanium dioxide added is 3% of the mass of the carbon material raw material (the amount added is lower than the range of 5%~8% as defined in claim 3). The mixture was stirred uniformly using only mechanical stirring (without using ultrasonic vibration in conjunction with mechanical stirring), with the stirring speed controlled at 60 r / min. A water bath was used to control the reaction temperature at 40℃ (lower than the 55℃~65℃ range specified in claim 5), with a temperature control accuracy of ±2℃. The pH and temperature of the reaction system were monitored in real time, and the reaction time was controlled at 20 min (lower than the 40 min~70 min range specified in claim 5) to complete the modification reaction. After the modification reaction was completed, the reaction mixture was separated to obtain solid products and waste liquid. The separated solid products were subjected to pressure filtration for dehydration, and simultaneously washed with deionized water until the pH of the washing liquid reached 6.5~7.5. The washing wastewater was collected. The washed solid product is dried by hot air circulation, with the drying temperature controlled at 100℃ and the drying time at 30 min. Then, the dried solid product is subjected to low-temperature calcination activation treatment, with the calcination temperature controlled at 200℃ (lower than the 250℃~280℃ range specified in claim 8) and the calcination time at 1 h, to obtain the flue gas desulfurization and denitrification adsorbent.

[0053] The adsorbent obtained in this comparative example was tested and found to have an adsorption capacity of 89 mg / g for SO2 and 8 mg / g for NO. x The adsorption capacity was 67 mg / g, the SO2 removal rate was 72.5%, and the NO removal rate was... x The removal rate was 65.3%. Compared to Example 1 (SO2 adsorption capacity 215 mg / g, NO...),... x Adsorption capacity 162 mg / g, SO2 removal rate 98.5%, NO x Compared to the control group (with a removal rate of 95.8%), the SO2 adsorption capacity of this control group decreased by approximately 59%, and the NO adsorption capacity decreased by approximately 59%. xThe adsorption capacity decreased by approximately 59%, and the removal rate was significantly reduced. The results indicate that when key parameters such as modifier concentration, raw material ratio, titanium dioxide addition, reaction temperature, reaction time, and calcination temperature deviated from the preferred range of this invention, and ultrasonic synergistic stirring was not employed, the active component loading was insufficient, the dispersion was uneven, and the modification reaction was incomplete, leading to decreased adsorption capacity for SO2 and NO. x The adsorption performance of the gas has decreased significantly, making it unable to meet the actual application requirements of flue gas desulfurization and denitrification.

[0054] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for preparing a high-efficiency flue gas desulfurization and denitrification adsorbent by modifying carbon materials, characterized in that, The method includes: Select carbon material raw materials, crush them, sieve the crushed carbon material raw materials, and then dry the sieved carbon material raw materials; A composite modifier solution was prepared using nitric acid solution and ferrous sulfate solution, and then stirred until homogeneous. The composite modifier solution is mixed with carbon material raw materials, and titanium dioxide is added at the same time to obtain a mixed material; The mixed materials are stirred evenly and then subjected to a modification reaction under the preset modification reaction conditions; After the modification reaction is completed, the reaction mixture is separated to separate the solid product and waste liquid; Recovery of modifiers from solid products; The solid product is dried and calcined at low temperature to obtain a dry flue gas desulfurization and denitrification adsorbent.

2. The method according to claim 1, characterized in that, A composite modifier solution was prepared using nitric acid solution and ferrous sulfate solution, including: A composite modifier solution was prepared by mixing 0.6 mol / L to 1.2 mol / L nitric acid solution and 0.3 mol / L to 0.5 mol / L ferrous sulfate solution at a volume ratio of 2:

1.

3. The method according to claim 1, characterized in that, A composite modifier solution is mixed with carbon material raw materials, and titanium dioxide is added simultaneously to obtain a mixed material, including: The composite modifier solution and the carbon material raw material are mixed at a mass ratio of (4-6):1, and titanium dioxide is added at the same time, wherein the mass of titanium dioxide is 5% to 8% of the mass of the carbon material raw material.

4. The method according to claim 1, characterized in that, Mix the ingredients thoroughly, including: The mixed materials are stirred evenly by a combination of ultrasonic vibration and mechanical stirring, wherein the ultrasonic power is controlled at 300W~350W and the stirring speed is 70r / min~80r / min.

5. The method according to claim 1, characterized in that, The modification reaction occurs under the preset modification reaction conditions, including: The reaction temperature was controlled by a water bath at 55℃~65℃ with a temperature control accuracy of ±2℃. The pH value and temperature of the reaction system were monitored in real time, and the reaction time was controlled at 40 min~70 min to complete the modification reaction.

6. The method according to claim 1, characterized in that, Recovery of modifiers from solid products, including: The separated solid products are subjected to pressure filtration and dehydration to reduce the water content of the solid products, while the residual modifiers in the solid products are squeezed out for recycling.

7. The method according to claim 6, characterized in that, The recovery of modifiers from solid products also includes: The solid product after pressure filtration and dehydration is washed with deionized water until the pH value of the washing solution reaches 6.5~7.5; Collect washing wastewater, regenerate the wastewater, and recover the modifiers contained therein.

8. The method according to claim 1, characterized in that, Drying and low-temperature calcination of solid products include: The solid product was dried using a hot air circulation drying method, with the drying temperature controlled at 115℃~120℃ and the drying time at 40min~50min. The dried solid product is subjected to low-temperature calcination activation treatment, wherein the calcination temperature is controlled at 250℃~280℃ and the calcination time is 1.5h~2h.

9. The method according to claim 1, characterized in that, After the adsorbent becomes saturated, the method further includes: The hot air purging regeneration method is adopted, with the purging temperature controlled at 180℃~200℃ and the purging time at 30min~40min, to purge the dry flue gas desulfurization and denitrification adsorbent and regenerate the adsorbent.

10. The method according to claim 9, characterized in that, The method further includes: The quality of the dried flue gas desulfurization and denitrification adsorbent and the regenerated adsorbent were tested to ensure that their adsorption capacity for SO2 was ≥200mg / g and their adsorption capacity for NO was ≥200mg / g. x Adsorption capacity ≥150mg / g, SO2 removal rate ≥98%, NO x Removal rate ≥ 95%.

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