Bagasse activated carbon fiber loaded iron-based low-temperature SCR (Selective Catalytic Reduction) denitration catalyst as well as preparation method and application thereof

Abstract

The invention discloses a bagasse activated carbon fiber loaded iron-based low-temperature SCR denitration catalyst and a preparation method and application thereof.The bagasse activated carbon fiber serves as a carrier, Fe oxide and Ce oxide serve as active ingredients, the mesh number of the bagasse activated carbon fiber is 40-120, and the mesh number of the Ce oxide is 10-30. The loading capacity of the component Fe is 1wt%-8wt% of the weight of the active carbon fiber carrier, and the loading capacity of the component Ce is 7wt%-20wt% of the weight of the active carbon fiber carrier. The catalyst disclosed by the invention has the characteristics of simple principle and convenience in preparation, has a relatively good denitration effect at low temperature, can well solve the problems of relatively low denitration efficiency and relatively high use temperature section of an existing denitration catalyst, and is beneficial to prolonging the service life of the catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and specifically relates to a bagasse activated carbon fiber supported iron-based low-temperature SCR denitration catalyst, its preparation method and application, which are mainly applied to low-temperature SCR denitration in waste incineration power plants. Background Art

[0002] Bagasse is the main by-product of the sugar industry, and the annual output of bagasse in the sugar industry is about 10 million tons. Therefore, properly handling the rational utilization of bagasse will improve the utilization efficiency of sugarcane. At present, the main uses of bagasse are in power generation by combustion, papermaking, production of artificial boards, and production of alcohol, etc. However, the activated carbon fibers stored in bagasse have not been more rationally utilized. The structure of activated carbon fiber (ACF) is quite different from that of general activated carbon (GAC). Its specific surface area, pore size, etc. are larger than those of general activated carbon (GAC), which is more conducive to the adsorption and loading of catalysts.

[0003] Nitrogen oxides (NO x ) are one of the harmful substances in air pollution. When accumulated in the air to a certain extent, they are likely to cause acid rain and photochemical smog, bringing serious impacts on the environment and human health. Therefore, the removal of NO x has become one of the important research topics in the current environmental protection field. In the existing technology, selective catalytic reduction (SCR) denitration technology is mainly used to control the NO x emitted from waste incineration, that is, under the action of a catalyst, a reducing agent (usually NH3 or urea) is used to reduce NO x to nitrogen and water with less impact on the atmospheric environment. The SCR process has high denitration efficiency and low NH3 escape rate, with simple process and high degree of automation, and has been widely used in industry.

[0004] Although the existing low-temperature denitration catalysts have improved the low-temperature denitration performance of the catalysts to a certain extent, the composition of their active components is relatively complex, the preparation process is rather cumbersome, and their denitration efficiency in the low-temperature section still needs to be further improved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the existing technology and provide a bagasse activated carbon fiber supported iron-based low-temperature SCR denitration catalyst with simple principle, convenient preparation, high stability and high catalytic efficiency, its preparation method and application.

[0006] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0007] A low-temperature SCR denitration catalyst based on iron supported by bagasse activated carbon fiber. The catalyst uses bagasse activated carbon fiber as the carrier and oxides of Fe and Ce as the active components. Among them, the mesh number of the bagasse activated carbon fiber is 40 mesh to 120 mesh, the loading amount of component Fe is 1 wt% to 8 wt% of the weight of the activated carbon fiber carrier, and the loading amount of component Ce is 7 wt% to 20 wt% of the weight of the activated carbon fiber carrier.

[0008] As a further improvement of the present invention, in the catalyst, the mesh number of the bagasse activated carbon fiber is 100 mesh, the loading amount of component Fe is 2 wt% of the weight of the activated carbon fiber carrier, and the loading amount of component Ce is 19 wt% of the weight of the activated carbon fiber carrier.

[0009] As a general technical concept, the present invention also provides a preparation method of a low-temperature SCR denitration catalyst based on iron supported by bagasse activated carbon fiber, including the following steps:

[0010] Step S1: Prepare a mixed solution of cerium nitrate and iron nitrate with a preset concentration;

[0011] Step S2: Weigh bagasse activated carbon fiber (ACF) and place it in a mixing container. Add the mixed solution of cerium nitrate and iron nitrate obtained in step S1 into the mixing container and stir evenly to obtain an ACF mixed solution;

[0012] Step S3: Immerse the ACF mixed solution obtained in step S2 for 10 h to 14 h, then put it into a drying oven for drying. The drying temperature is 100 °C to 140 °C, and the drying duration is 10 h to 14 h to obtain a Fe2O3-CeO2 / ACF catalyst;

[0013] Step S4: After the Fe2O3-CeO2 / ACF catalyst reaches the preset drying duration, continue heating and drying to make cerium nitrate and iron nitrate fully pyrolyze to generate iron oxide and cerium oxide.

[0014] As a further improvement of the present invention, in step S2, the preparation method of the bagasse activated carbon fiber includes the following steps:

[0015] Step Y1: Wash the bagasse with clean water and then soak it;

[0016] Step Y2: Wring out the soaked bagasse and put it into a drying oven for drying. The drying temperature is 100 °C to 110 °C, and the drying duration is 6 h to 10 h;

[0017] Step Y3: Put the dried bagasse into a muffle furnace for carbonization;

[0018] Step Y4: Grind the carbonized bagasse into powder to obtain bagasse carbon fiber;

[0019] Step Y5: Place the bagasse carbon fiber in a U-shaped tube, connect the U-shaped tube to a test tube filled with distilled water, heat the test tube to generate steam that flows through the U-shaped tube to activate the bagasse carbon fiber in the U-shaped tube.

[0020] Step Y6: Pour out the bagasse carbon fiber after the boiling activation is completed, and place it in a drying oven for drying. The drying temperature is 100°C to 110°C, and the drying duration is 10h to 14h to obtain bagasse activated carbon fiber.

[0021] As a further improvement of the present invention, in the step Y3, the carbonization temperature is 500 ± 10°C, and the carbonization duration is 60 ± 5s.

[0022] As a further improvement of the present invention, in the steps S1 and S2, the cerium nitrate is Ce(NO3)3·6H2O, and the mass ratio of cerium nitrate to bagasse activated carbon fiber is (0.2 - 0.5):1.

[0023] As a further improvement of the present invention, in the steps S1 and S2, the ferric nitrate is Fe(NO3)3·9H2O, and the mass ratio of ferric nitrate to bagasse activated carbon fiber is (0.1 - 0.4):1.

[0024] As a further improvement of the present invention, in the step S2, the mesh number of the bagasse activated carbon fiber is 100 mesh.

[0025] As a general technical concept, the present invention also provides an application of a bagasse activated carbon fiber supported iron-based low-temperature SCR denitration catalyst. When the catalyst is used in the SCR denitration technology, the flow rate ratio of NH3 to NO is controlled to be (0.20 - 0.35):1, the flow rate ratio of oxygen to NO is (10 - 20):1, the reaction duration is 5 - 60 min, and the reaction temperature is 110°C to 200°C.

[0026] As a further improvement of the present invention, the reaction temperature is 170°C to 200°C.

[0027] Compared with the prior art, the advantages of the present invention are as follows:

[0028] 1. The iron-based low-temperature SCR denitration catalyst supported on bagasse activated carbon fibers of the present invention uses bagasse activated carbon fibers as the carrier and oxides of Fe and Ce as the active components. Through the synergistic effect of Fe and Ce, the catalytic activity is significantly improved. At the same time, by optimizing and controlling the loading amounts of each component, good mutual coordination among the components can be achieved, so that the SCR denitration catalyst has good denitration effect at low temperature (110-200 °C), which is beneficial to reducing energy consumption and cost, and can be applied to the situation where the temperature is relatively low after flue gas desulfurization and dust removal in existing waste incineration power plants and low-temperature denitration in coking plants, ensuring its low-temperature denitration effect.

[0029] 2. The preparation method of the iron-based low-temperature SCR denitration catalyst supported on bagasse activated carbon fibers of the present invention uses bagasse activated carbon fibers as the carrier and the mixed oxides of Fe and Ce as the active components. The active components are loaded on the carrier by the impregnation method, and at the same time, the loading amounts of Fe and Ce and the specific preparation process parameters are optimized and designed, so that the low-temperature denitration efficiency of the catalyst can be effectively improved, ensuring its low-temperature denitration effect. Moreover, this preparation process is relatively simple, so it has high research value and is worthy of promotion. Brief Description of the Drawings

[0030] Figure 1 It is a curve graph of the denitration efficiency of the catalyst at different reaction temperatures in the specific embodiment of the present invention;

[0031] Figure 2 It is a curve graph of the denitration efficiency of the catalyst at different ammonia-nitrogen ratios in the specific embodiment of the present invention;

[0032] Figure 3 It is a curve graph of the denitration efficiency of the catalyst at different oxygen concentrations in the specific embodiment of the present invention;

[0033] Figure 4 It is a curve graph of the denitration efficiency of the catalyst at different reaction times in the specific embodiment of the present invention; Detailed Embodiment

[0034] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0035] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "side", "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0036] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0037] Example 1

[0038] The preparation method of the iron-based low-temperature SCR denitration catalyst supported on bagasse activated carbon fiber of the present invention includes the following steps:

[0039] Step S1: Weigh a certain mass of Ce(NO3)3·6H2O and Fe(NO3)3·9H2O, and prepare a mixed solution of cerium nitrate and iron nitrate with a preset concentration.

[0040] Step S2: Weigh bagasse activated carbon fibers (ACF) with different mesh numbers and place them in beakers respectively. Add the mixed solution of cerium nitrate and iron nitrate obtained in step S1 into the beakers, heat and stir evenly through a magnetic stirrer in a water bath to obtain an ACF mixed solution. It should be noted that this step has two cases. One is the orthogonal experiment, in which 0.5 g of ACF is taken for each group and then directly added to the prepared mixed solution. The other is the single-factor experiment, in which the ACF with the best mesh number is taken, and then mixed solutions with different concentrations are prepared according to a ratio and added to the ACF to prepare the catalyst.

[0041] Step S3: Immerse the ACF mixed solution obtained in step S2 for 12 h, and then put it into a forced-air drying oven for drying. The drying temperature is 120 °C and the drying duration is 12 h to obtain the Fe2O3-CeO2 / ACF catalyst.

[0042] Step S4: After the Fe2O3-CeO2 / ACF catalyst reaches the preset drying time, continue heating and drying for a certain period of time as a pyrolysis step, so that cerium nitrate and iron nitrate are fully pyrolyzed to generate iron oxide and cerium oxide. The prepared catalyst is labeled and stored in separate bags. At this point, the preparation of the Fe2O3-CeO2 / ACF catalyst is completed.

[0043] In this embodiment, the preparation method of bagasse activated carbon fiber specifically comprises the following steps:

[0044] Step Y1: Collect a certain amount of bagasse, wash it with clean water, and soak it overnight to dilute the sugar in the bagasse to the maximum extent.

[0045] Step Y2: wring out the soaked bagasse and put it into a forced air drying oven for drying. The drying oven is set at a temperature of 105° C. and dried for about 8 hours until the bagasse is completely dry.

[0046] Step Y3, take out the dried bagasse, and heat the muffle furnace to 500°C and maintain a constant temperature, then divide the bagasse into several portions and put them in a crucible, and place the crucible in the muffle furnace to carbonize the bagasse. The carbonization time depends on the situation and is set at 60 seconds.

[0047] Step Y4, grind the carbonized bagasse into powder, collect the ground bagasse carbon fiber, and sieve it into powders, using 40 mesh, 60 mesh, 80 mesh, and 100 mesh filter sieves respectively, and repeat this step until the bagasse carbon fiber is completely divided into four meshes.

[0048] Step Y5, placing bagasse carbon fibers of different mesh sizes in a U-shaped tube, connecting the U-shaped tube to a test tube filled with distilled water, heating the test tube to generate water vapor to flow through the U-shaped tube, and activating the bagasse carbon fibers in the U-shaped tube.

[0049] Step Y6, pour out the boiled activated bagasse carbon fiber and put it into a drying oven for drying at a temperature of 105°C for 12 hours to obtain bagasse activated carbon fiber. Divide the dried bagasse activated carbon fiber into 4 mesh sizes, namely: 40 mesh, 60 mesh, 80 mesh, and 100 mesh. Store in bags. At this point, the preparation of bagasse activated carbon fiber is completed.

[0050] In this embodiment, an orthogonal experiment with three factors and four levels is adopted to obtain the optimal catalyst ratio. The three factors of the experiment are: the mesh number of bagasse activated carbon fiber, the mass of cerium oxide, and the mass of iron oxide. Among the four levels, the mesh numbers of bagasse activated carbon fiber are 40 mesh, 60 mesh, 80 mesh, and 100 mesh respectively; the masses of cerium oxide (CeO2) are 0.0396 g, 0.0608 g, 0.0793 g, and 0.0990 g respectively. At this time, the masses of Ce(NO3)3·6H2O taken can be calculated as: 0.10 g, 0.15 g, 0.20 g, and 0.25 g respectively; the masses of iron oxide (Fe2O3) are 0.0099 g, 0.0198 g, 0.0297 g, and 0.0396 g respectively. At this time, the masses of Fe(NO3)3·9H2O taken can be calculated as: 0.05 g, 0.10 g, 0.15 g, and 0.20 g respectively. As shown in Table 1:

[0051] Table 1. Orthogonal factor level table

[0052]

[0053] Table 2. Header of the orthogonal table of Fe2O3-CeO2 / ACF catalyst

[0054]

[0055] Table 3. Data table of orthogonal experiment of Fe2O3-CeO2 / ACF catalyst

[0056]

[0057]

[0058] In this embodiment, the orthogonal experiment is carried out under the condition of 110 °C. The flue gas ratio scheme is NO: 3 mL / min, SO2: 0 mL / min, N2: 0.56 L / min, O2: 30 mL / min, NH3: 0.6 mL / min. The catalyst dosage for each group is 0.5 g. According to the orthogonal experiment scheme, the experimental data measured are listed in Table 3. According to the header of the orthogonal table of Fe2O3-CeO2 / ACF catalyst in Table 2, assuming that the mesh number of bagasse activated carbon fiber ACF is A; the mass of added CeO2 is B; the mass of added Fe2O3 is C, the average value of the denitration efficiency corresponding to different levels is calculated for the catalyst mesh number A in the data table of the orthogonal experiment of Fe2O3-CeO2 / ACF catalyst in Table 3 to obtain the average catalyst denitration efficiency under different mesh number conditions. It is denoted as:

[0059] K1 A =(54.217 + 56.250 + 56.958 + 55.017)÷4 = 55.610 (1)

[0060] K2 A =(53.858 + 54.867 + 50.067 + 53.033)÷4 = 52.956 (2)

[0061] K3 A =(52.717 + 51.833 + 52.683 + 51.242)÷4 = 52.119 (3)

[0062] K4 A =(56.183 + 55.617 + 56.033 + 60.492)÷4 = 57.081 (4)

[0063] It can be concluded therefrom that the average catalytic efficiencies of the catalysts prepared from bagasse activated carbon fibers with 40 mesh, 60 mesh, 80 mesh, and 100 mesh are 55.610%, 52.956%, 52.119%, and 57.081% respectively. When the fineness of the carbon fiber reaches a certain level, it will greatly affect the specific surface area of the ACF, thereby changing the adsorption efficiency of the catalyst, resulting in different masses of the supported Fe2O3-CeO2 and thus different catalytic efficiencies. When the particle size of the bagasse activated carbon fiber is 100 mesh, the adsorption of Fe2O3-CeO2 by the bagasse activated carbon fiber increases, thereby increasing the catalytic efficiency of the activated carbon fiber catalyst.

[0064] Using the same principle for the mass of CeO2 added, the average catalytic efficiencies under different masses of supported CeO2 are calculated respectively.

[0065] K1 B =(54.217 + 53.858 + 52.717 + 56.183)÷4 = 54.244 (5)

[0066] K2 B =(56.250 + 54.867 + 51.833 + 55.617)÷4 = 54.642 (6)

[0067] K3 B =(56.958 + 50.067 + 52.683 + 56.033)÷4 = 53.935 (7)

[0068] K4 B =(55.017 + 53.033 + 51.242 + 60.492)÷4 = 54.946 (8)

[0069] It can be seen from the calculation results that when the masses of CeO2 added are 0.0396 g, 0.0608 g, 0.0793 g, and 0.0990 g respectively, the corresponding denitrification catalytic efficiencies of the bagasse catalysts are 54.244%, 54.642%, 53.935%, and 54.946% respectively. The influence of the mass of CeO2 incorporated on the denitrification efficiency of the catalyst basically shows an upward trend, that is, the greater the mass of CeO2, the higher the catalyst efficiency.

[0070] Then, for the mass of Fe2O3 added, the above method is also used to calculate the average catalytic efficiency at different masses of supported Fe2O3.

[0071] K1 C =(54.217 + 54.867 + 52.683 + 60.492) ÷ 4 = 55.565 (9)

[0072] K2 C =(56.250 + 53.858 + 51.242 + 56.033) ÷ 4 = 54.346 (10)

[0073] K3 C =(56.958 + 53.033 + 52.717 + 55.617) ÷ 4 = 54.581 (11)

[0074] K4 C =(55.017 + 50.067 + 51.833 + 56.183) ÷ 4 = 53.275 (12)

[0075] According to the calculation data, it can be obtained that when the masses of Fe2O3 added are 0.0099 g, 0.0198 g, 0.0297 g, and 0.0396 g respectively, the corresponding denitrification efficiencies of the catalysts are 55.565%, 54.346%, 54.581%, and 53.275% respectively. The influence of the mass of Fe2O3 incorporated on the denitrification efficiency of the catalyst basically shows a downward trend.

[0076] Calculating the range of the average catalytic efficiency under each factor gives:

[0077] R A = 4.962 (13)

[0078] R B = 1.010 (14)

[0079] R C = 2.290 (15)

[0080] According to the experimental data, it can be obtained that the denitrification efficiency of the 16th group of experiments is the highest, at 60.492%. Therefore, the optimal working conditions shown by the orthogonal experiment are as follows: 100-mesh bagasse activated carbon fiber, the mass of CeO2 added is 0.0990 g, and the mass of Fe2O3 added is 0.0099 g. At this time, the best efficiency is achieved at a temperature of 110 °C.

[0081] According to the calculated data of the range, it can also be obtained that the influence degrees of the three factors of the bagasse activated carbon fiber mesh number, the CeO2 addition amount, and the Fe2O3 addition amount on the catalytic efficiency of the catalyst are as follows: bagasse activated carbon fiber mesh number > mass of Fe2O3 added > mass of CeO2 added.

[0082] Example 2

[0083] In this example, the catalyst prepared under the optimal ratio conditions is applied to the low-temperature SCR denitrification reaction. According to the conventional settings in this field, a flue gas analyzer and a gas-solid reaction device are used to simulate the tail flue gas situation of a waste incineration power plant, and the influence of the denitrification reaction temperature on the denitrification efficiency of the catalyst is explored. The set NO flow rate is: 3 mL / min; the set NH3 flow rate is: 0.6 mL / min; the set O2 flow rate is: 30 mL / min; the set N2 flow rate is: 0.56 L / min. After the experiment starts, data is recorded when the flue gas analyzer is stable.

[0084] It should be noted that in this example, the catalytic efficiency of the catalyst and the influence of each reaction factor are mainly detected by the change in the concentration of NO. Therefore, the NO removal efficiency needs to be calculated at the end of the experiment. The specific calculation formula is as follows:

[0085]

[0086] Among them:

[0087] NO in —— The inlet concentration of nitrogen monoxide (NO), unit ppm;

[0088] NO out —— The outlet concentration of nitrogen monoxide (NO), unit ppm;

[0089] η ———— The removal efficiency of nitrogen monoxide (NO), unit %.

[0090] When the NO mass flow rate is: 3 ml / min, the NO inlet concentration at this time is 1000 ppm. The same explanation applies to other examples.

[0091] Such as Figure 1As shown in the figure, the denitrification efficiency of the bagasse Fe2O3-CeO2 / ACF catalyst shows two-stage variation trends with the change of temperature. In the range of 110°C to 170°C, the catalyst efficiency shows a downward trend. In the range of 170°C to 200°C, the efficiency of the bagasse Fe2O3-CeO2 / ACF catalyst increases with the increase of temperature. Moreover, in this temperature range, the efficiency increases significantly. It can be seen that after the temperature reaches 170°C, the temperature has a significant impact on the efficiency of the catalyst, and the higher temperature promotes the catalytic efficiency of the catalyst.

[0092] Example 3

[0093] In this example, the catalyst prepared under the optimal ratio conditions was applied to the low-temperature SCR denitrification reaction. According to the conventional settings in the field, a flue gas analyzer and a gas-solid reaction device were used to simulate the tail flue gas situation of a waste incineration power plant, and the influence of the reaction ammonia-nitrogen ratio on the denitrification efficiency of the catalyst was explored.

[0094] The so-called ammonia-nitrogen ratio is the molar ratio of ammonia and NO x introduced into the pipeline during the denitrification experiment. In this example, NO was mainly considered, so the molar mass of NO was used to replace the molar mass of NO x Thus, the amount of NO x introduced was the measured amount of NO. According to the chemical reaction equation as follows:

[0095]

[0096] It can be obtained that under normal conditions, 1 mol of NO should react with 1 mol of NH3, that is, the ideal ammonia-nitrogen ratio is 1:1. However, in general, NH3 will leak, so more needs to be introduced.

[0097] The entire denitrification reaction was carried out at 120°C; the oxygen flow rate was set at 30 mL / min; the NO x flow rate, that is, the flow rate of NO, was set at 3.0 mL / min; the flow rate of N2 was set at 0.56 L / min. Three different NH3 flow rates were selected, namely 0.6 mL / min, 0.8 mL / min, and 1.0 mL / min. After the experiment started, data were recorded when the flue gas analyzer was stable.

[0098] As Figure 2As shown in the figure, when the NH3 flow rate is 0.8 mL / min and the NO flow rate is 3.0 mL / min, the denitrification efficiency of the bagasse Fe2O3-CeO2 / ACF catalyst is the best, reaching 62% - 64%. At this time, the ammonia-nitrogen ratio is n[NH3]∶n[NO] = 4∶3. From the experimental results, when the NH3 flow rate is 0.6 mL / min and 1.0 mL / min, the denitrification efficiency of the obtained catalyst is significantly lower than that of the best group. Analyzing the reasons, when the NH3 flow rate is 0.6 mL / min, due to the insufficient NH3 concentration, the reductant for SCR is insufficient, and at this time, NO cannot react fully, resulting in a lower denitrification efficiency of the flue gas catalyst; when the NH3 flow rate is 1.0 mL / min, the NH3 concentration is too high, and the excessive NH3 can be oxidized to form NO, thus reducing the catalytic efficiency, wasting ammonia, and also hindering the progress of the SCR reaction.

[0099] Example 4

[0100] In this example, the catalyst prepared under the optimal ratio conditions was applied to the low-temperature SCR denitrification reaction. According to the conventional settings in the art, a flue gas analyzer and a gas-solid reaction device were used to simulate the tail flue gas situation of a waste incineration power plant, and the influence of oxygen concentration on the denitrification efficiency of the catalyst was explored.

[0101] The reaction temperature was 120 °C. The NO flow rate introduced in the experiment was set at 3.0 mL / min, the nitrogen flow rate was set at 0.56 L / min, the ammonia flow rate was set at 0.6 mL / min, and the oxygen concentrations were: 30 mL / min, 40 mL / min, 50 mL / min, and 60 mL / min. After the experiment started, data was recorded when the flue gas analyzer was stable.

[0102] As Figure 3 shown, as the oxygen concentration increased, the denitrification efficiency of the bagasse Fe2O3-CeO2 / ACF catalyst gradually increased, indicating that the oxygen concentration has a positive effect on the catalyst efficiency. At the same time, it can be seen from the curve in Figure 3 that as the oxygen concentration increased, the increase amplitude of the efficiency became smaller and smaller, indicating that there is a saturation value for oxygen. When the oxygen concentration continues to increase, the influence on the denitrification efficiency will become smaller and smaller, or remain unchanged. Generally speaking, oxygen promotes the progress of the denitrification reaction and is beneficial to the reduction of NO x by ammonia.

[0103] Example 5

[0104] In this embodiment, the catalyst prepared under the optimal ratio conditions is applied to the low-temperature SCR denitrification reaction. According to the conventional settings in the art, a flue gas analyzer and a gas-solid reaction device are used to simulate the tail flue gas situation of a waste incineration power plant, and the influence of different reaction times on the denitrification efficiency of the catalyst is explored.

[0105] The mesh number of the bagasse activated carbon fiber is 40 mesh. For Catalyst #1: the mass of the supported cerium oxide (CeO2) is 0.0396 g, and the mass of the supported iron oxide (Fe2O3) is 0.0099 g; for Catalyst #2: the mass of the supported cerium oxide (CeO2) is 0.0608 g, and the mass of the supported iron oxide (Fe2O3) is 0.0198 g; for Catalyst #3: the mass of the supported cerium oxide (CeO2) is 0.0793 g, and the mass of the supported iron oxide (Fe2O3) is 0.0297 g; for Catalyst #4: the mass of the supported cerium oxide (CeO2) is 0.0990 g, and the mass of the supported iron oxide (Fe2O3) is 0.0396 g. The same reaction state of the four groups of catalysts is as follows: the reaction is carried out at 110 °C, and the flue gas ratio scheme is NO: 3 mL / min, N2: 0.56 L / min, O2: 30 mL / min, and NH3: 0.6 mL / min. After the experiment starts, data is recorded when the flue gas analyzer is stable.

[0106] As Figure 4 shown, for the four groups of bagasse Fe2O3-CeO2 / ACF catalysts with different loadings, as the reaction time increases, the catalytic denitrification rate of the bagasse Fe2O3-CeO2 / ACF catalyst shows a certain downward trend. It can be seen that the catalyst will be consumed as the reaction proceeds, resulting in a decrease in the catalytic efficiency and further affecting the denitrification process. However, the overall decrease amplitude is not large, and the entire decrease efficiency is within 4%. It can be seen that the influence of time on the catalyst is not significant, and the durability of the bagasse Fe2O3-CeO2 / ACF catalyst is relatively strong. However, after all, the bagasse Fe2O3-CeO2 / ACF catalyst will be affected by time. Therefore, when treating the tail flue gas in a waste incineration power plant, the catalyst needs to be replaced at regular intervals to ensure normal denitrification and avoid environmental pollution to the atmosphere.

[0107] The above is only the preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, several improvements and refinements made without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A bagasse activated carbon fiber-supported iron-based low-temperature SCR denitration catalyst, characterized in that: The catalyst uses bagasse activated carbon fiber as a carrier and Fe oxide and Ce oxide as active ingredients, wherein the mesh number of the bagasse activated carbon fiber is 40 to 120 meshes, the loading amount of the component Fe is 1wt% to 8wt% of the weight of the activated carbon fiber carrier, and the loading amount of the component Ce is 7wt% to 20wt% of the weight of the activated carbon fiber carrier.

2. The bagasse activated carbon fiber-supported iron-based low-temperature SCR denitration catalyst according to claim 1, characterized in that: In the catalyst, the mesh number of bagasse activated carbon fiber is 100 meshes, the loading amount of component Fe is 2wt% of the weight of the activated carbon fiber carrier, and the loading amount of component Ce is 19wt% of the weight of the activated carbon fiber carrier.

3. A method for preparing the bagasse activated carbon fiber-supported iron-based low-temperature SCR denitration catalyst as claimed in claim 1 or 2, characterized in that: The following steps are involved: Step S1, preparing a mixed solution of cerium nitrate and ferric nitrate with a preset concentration; Step S2, weighing bagasse activated carbon fiber (ACF) and placing it in a mixing container, adding the mixed solution of cerium nitrate and ferric nitrate obtained in step S1 into the mixing container, and stirring evenly to obtain an ACF mixed solution; Step S3, immersing the ACF mixed solution obtained in step S2 for 10 h to 14 h, and then drying it in a drying oven at a drying temperature of 100° C. to 140° C. for a drying time of 10 h to 14 h, to obtain a Fe2O3-CeO2 / ACF catalyst; Step S4: After the Fe2O3-CeO2 / ACF catalyst reaches a preset drying time, heating and drying are continued to allow the cerium nitrate and iron nitrate to be fully pyrolyzed to generate iron oxide and cerium oxide.

4. The method for preparing the bagasse activated carbon fiber-supported iron-based low-temperature SCR denitration catalyst according to claim 3, characterized in that: In step S2, the method for preparing bagasse activated carbon fiber comprises the following steps: Step Y1, washing the bagasse with clean water and soaking it; Step Y2, wring out the soaked bagasse and put it into a drying oven for drying at a temperature of 100° C. to 110° C. for a drying time of 6 h to 10 h; Step Y3, placing the dried bagasse into a muffle furnace for carbonization; Step Y4, grinding the carbonized bagasse into powder to obtain bagasse carbon fiber; Step Y5, placing the bagasse carbon fiber in a U-shaped tube, connecting the U-shaped tube to a test tube filled with distilled water, heating the test tube to generate water vapor to flow through the U-shaped tube, and activating the bagasse carbon fiber in the U-shaped tube; Step Y6, pour out the sugarcane bagasse carbon fiber that has been activated by boiling, and put it into a drying oven for drying at a temperature of 100° C. to 110° C. for a drying time of 10 h to 14 h to obtain sugarcane bagasse activated carbon fiber.

5. The method for preparing the bagasse activated carbon fiber-supported iron-based low-temperature SCR denitration catalyst according to claim 4, characterized in that: In step Y3, the carbonization temperature is 500±10° C., and the carbonization time is 60±5 s.

6. The method for preparing the bagasse activated carbon fiber-supported iron-based low-temperature SCR denitration catalyst according to claim 3, characterized in that: In the step S1 and step S2, the cerium nitrate is Ce(NO3)3·6H2O, and the mass ratio of cerium nitrate to bagasse activated carbon fiber is (0.2-0.5):

1.

7. The method for preparing the bagasse activated carbon fiber-supported iron-based low-temperature SCR denitration catalyst according to claim 3, characterized in that: In the step S1 and step S2, the ferric nitrate is Fe(NO3)3·9H2O, and the mass ratio of ferric nitrate to bagasse activated carbon fiber is (0.1-0.4):

1.

8. The method for preparing the bagasse activated carbon fiber-supported iron-based low-temperature SCR denitration catalyst according to claim 3, characterized in that: In the step S2, the mesh size of the bagasse activated carbon fiber is 100 meshes.

9. An application of the bagasse activated carbon fiber supported iron-based low-temperature SCR denitration catalyst as claimed in claim 1 or 2, characterized in that: When the catalyst is used in SCR denitration technology, the flow rate ratio of NH3 to NO is controlled to be (0.20-0.35):1, the flow rate ratio of oxygen to NO is controlled to be (10-20):1, the reaction time is 5-60 minutes, and the reaction temperature is 110°C-200°C.

10. The use of bagasse activated carbon fiber supported iron-based low-temperature SCR denitration catalyst according to claim 9, characterized in that: The reaction temperature is 170°C to 200°C.

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