Cerium-based catalyst based method for reducing emission and denitrifying and removing dioxin of sintering smoke

[0049] Example 1

[0050] In this embodiment, a method for reducing sintering flue gas denitration and dioxin removal based on a cerium-based catalyst. The flue gas passes through an emission reduction device loaded with a cerium-based catalyst, and NH is blown into the emission reduction device 3 And air, where the cerium-based catalyst includes Ce: Mn and Fe, where the molar ratio of Ce: Mn is both 0.25 to 1, and Fe is the auxiliary agent, and the addition ratio ranges from 0.25 to 0.5. The cerium-based catalyst of this embodiment includes Ce: Mn and Fe, wherein the molar ratio of Ce: Mn is both 0.25, and Fe is an auxiliary agent, and the addition ratio ranges from Fe: Mn to 0.25.

[0051] Where NH 3 The injected mass is 10-20% of the mass content of nitrogen oxides in the sintering flue gas, which is taken as 10% in this embodiment; the injected air quantity is 5-10% of the other contents of the sintering flue gas, which is 8% in this embodiment. No additional heating of the sintering flue gas is required. It was detected that the denitration efficiency was 85%, and the dioxin emission reduction efficiency was 50%. However, the outlet temperature of the sintering flue gas is within 100-200°C, while the existing catalysts show quite high catalytic activity above 300°C. When the temperature is lower than 300°C, the catalytic activity is often very low, and the reheating of the sintering flue gas will consume a lot of Energy, increase energy consumption. However, the present invention realizes that in a low temperature state, without heating, the nitrogen oxides and dioxins in the flue gas can be reduced by using a cerium-based catalyst, and the low-temperature catalytic degradation of pollutants is realized.

[0052] The emission reduction mechanism is that the cerium-based catalyst promotes NH during the catalytic reduction process. 3 Reduce nitrogen oxides in flue gas to produce N 2 The cerium-based catalyst promotes the reduction and decomposition of dioxins in the flue gas during the catalytic reduction process to generate five poisonous substances. The PCDD/Fs in the gas phase can be chemically degraded at low temperature under the action of the metal catalyst to produce the final product CO 2 , H 2 O and HCl. The reaction process is as follows:

[0053] C1 2 H n Cl 8 -nO 2 +(9+0.5n)O 2 →(n-4)H 2 O+12CO 2 +(8-n)HCl

[0054] C1 2 H n Cl 8 -nO+(9.5+0.5n)O 2 →(n-4)H 2 O+12CO 2 +(8-n)HCl

[0055] The preparation method of the cerium-based catalyst used in this embodiment is: adding ferrous sulfate, manganese chloride, cerium nitrate and water into the mixing device 10, mixing to obtain a catalyst active component solution; and then transferring the catalyst active component solution Into the reaction chamber 100 of the preparation device 20, the ice water bath 110 outside the reaction chamber 100 cools the catalyst active component solution to 0-5°C, and then the oxalic acid solution in the oxalic acid pool 200 is added to the catalyst active component through the oxalic acid dropper 210 In the divided solution, the reaction chamber 100 mixes and reacts to generate precipitates during the stirring process, and the precipitates are filtered, washed, dried and then added to the roasting device 30 for roasting, and the catalyst is obtained after roasting.

[0056] S100, preparation of active component solution

[0057] Take 3.3~6.6 parts of FeSO 4 ·7H 2 O, 9.5 parts MnCl 2 ·4H 2 O, 1.3~5.2 parts of Ce(NO 3 ) 3 ·6H 2 O and deionized water are added to the mixing device 10, the mixing device 10 stirring speed 200r/min, stirring time 30min; mixed in the mixing device 10 to obtain the catalyst active component solution A; it is worth noting that this Example of taking 3.3g of FeSO 4 ·7H 2 O, 9.5g MnCl 2 ·4H 2 O, 1.3g Ce(NO 3 ) 3 ·6H 2 O and deionized water are added to the mixing device 10 and mixed to obtain a catalyst active component solution A;

[0058] S200, prepare oxalic acid solution

[0059] Add water to the oxalic acid pool 200 of the preparation device 20, turn on the heating and heat preservation component 220, which is used to heat and heat the oxalic acid pool 200 and the oxalic acid dropper 210, and keep the liquid temperature of the oxalic acid pool 200 to 60°C, Then add oxalic acid powder to the solution, stirring speed 200r/min, stirring time 30min, and mix evenly to prepare oxalic acid aqueous solution B;

[0060] S300, prepare precipitation solution

[0061] 1) The catalyst active component solution A is added to the reaction chamber 100 by the mixing device 10, and the catalyst active component solution A in the reaction chamber 100 is cooled by the ice water bath 110 and the cold air jet unit 140, and the catalyst active component Cool solution A to 0~5℃;

[0062] 2) Adjust the angle of rotation of the rotating support rod 151 and the telescopic length of the telescopic support arm 152, so that the oxalic acid dropper 210 and the hot gas nozzle 133 are arranged correspondingly, the hot gas jet unit 130 is turned on, and the hot gas nozzle 134 sprays heating gas into the reaction chamber 100 , The hot gas heats the liquid on the surface of the reaction chamber 100, and then the oxalic acid aqueous solution B is added to the catalyst active component solution A, and then the oxalic acid aqueous solution B at a temperature of 60°C is added to the catalyst active component solution A in the reaction chamber 100 , And the oxalic acid solution is dropped at the position corresponding to the hot air nozzle 134, and the stirring is continued to obtain the precipitation solution C;

[0063] 400. Preparation of catalyst

[0064] The precipitate solution C was filtered to obtain a precipitate, and the obtained precipitate was washed with deionized water, filtered three times with suction, then washed with anhydrous ethanol solution, and filtered three times with suction. The obtained precipitate was dried at 70°C for 12 hours, and the dried The latter precipitate is added to the roasting device 30 for roasting, wherein the roasting temperature is 300-500°C, the heating rate during the roasting process is 1-2°C/min; the oxidation roasting time is 1 to 1.5 hours; the roasting of this embodiment The temperature is 400°C, the heating rate during the roasting process is 2°C/min; the oxidation roasting time is 1 hour to obtain the roasted product. Then, the calcined product is added to the grinding device 40 for grinding, and the pass rate of the particles obtained by grinding is greater than 90% to obtain a cerium-based catalyst. The cerium-based catalyst of this embodiment includes Ce: Mn and Fe, wherein the molar ratio of Ce: Mn is both 0.25, and Fe is an auxiliary agent, and the addition ratio ranges from Fe: Mn to 0.25. The specific surface area of ​​the cerium-based catalyst is 84m -2 /g; The pore volume of the catalyst is 0.17m -2 /g, the pore size is 5.5nm. The electron microscope picture of the prepared cerium-based catalyst is as follows Figure 4 As shown, the analysis in the figure shows that the prepared cerium-based catalyst is in a mesoporous state, the specific surface area of ​​the catalyst is relatively large, and the catalytic activity of the catalyst is relatively high.

[0065] Example 2

[0066] Reference attached figure 1 As shown, the production system of a cerium-based catalyst for synergistic removal of dioxins and nitrogen oxides of the present invention includes a mixing device 10, a preparation device 20, and a roasting device 30 arranged in sequence; wherein the mixing device 10 is used for The reaction component solutions are mixed, and the mixing device 10 includes a mixing tank 300 and a stirring mechanism 310. The stirring mechanism 310 is arranged at the upper part of the mixing tank 300, and the stirring blade 311 at the bottom of the stirring mechanism 310 extends to the inside of the mixing tank 300 , The bottom of the mixing tank 300 is connected to the preparation device 20 through a pipeline, and a control valve 301 is provided on the pipeline.

[0067] Such as figure 2 with image 3 As shown, the above-mentioned preparation device 20 is used to prepare catalyst products. The preparation device 20 includes a reaction chamber 100 and an oxalic acid tank 200. The upper part of the reaction chamber 100 is provided with an oxalic acid tank 200. The oxalic acid tank 200 is provided with an electromagnetic stirring mechanism 201 and Mechanical stirrer 202; electromagnetic stirring mechanism 201 and mechanical stirrer 202 are used to stir the oxalic acid solution in the oxalic acid pool 200.

[0068] An oxalic acid dropper 210 is provided under the oxalic acid pool 200, a telescopic support arm 152 is provided on the top of the reaction chamber 100, and the telescopic support arm 152 is connected to the top of the reaction chamber 100 by a rotating support rod 151. The end of the telescopic support arm 152 is provided with a clamp The holding mechanism 153 is used to hold the oxalic acid dropper 210. The oxalic acid dropper 210 is fixed to the upper part of the reaction chamber 100 by the holding mechanism 153; the rotation angle of the rotating support rod 151 and the telescopic support arm 152 can be adjusted by The length of the oxalic acid dropper 210 is corresponding to the hot gas nozzle 133, so that the liquid sprayed by the hot gas nozzle 133 only heats the liquid at the corresponding position of the oxalic acid dropper 210. An oxalic acid valve 230 is provided on the oxalic acid dropper 210, and the oxalic acid valve 230 is used to control the flow of the oxalic acid solution.

[0069] The outside of the oxalic acid pool 200 and the oxalic acid dropper 210 are provided with a heating and heat preservation component 220, which is used to heat and keep the oxalic acid pool 200 and the oxalic acid dropper 210; an ice water bath 110, ice water is provided outside the reaction chamber 100 The bath 110 is used to cool the reaction chamber 100 in a water bath. The water bath cooling of the ice water bath 110 can keep the catalyst active component solution A in the reaction chamber 100 cool, and keep the catalyst active component solution A at a relatively stable temperature for reaction Therefore, the stability of the prepared product and the performance of the product are ensured, and the mesoporous performance and catalytic performance of the catalyst can be improved; the roasting device 30 is used to roast the product prepared by the preparation device 20.

[0070] The reaction chamber 100 of this embodiment is provided with a hot gas nozzle 133. The hot gas nozzle 134 on the top of the hot gas nozzle 133 is corresponding to the oxalic acid dropper 210. The hot gas nozzle 133 is connected to the first gas tank 131, and the hot gas nozzle 133 is A gas heater 132 is provided, and the gas heater 132 is used to heat the first gas tank 131 and together constitute a hot jet unit 130, which is used to heat the surface liquid. The hot gas nozzle 134 of the hot gas nozzle 133 blows heating gas into the reaction chamber 100, and the temperature of the heating gas is 60-80°C. The hot gas shower head 134 is provided with a temperature sensor, and is used to detect the temperature of the gas ejected from the hot gas shower head 134, adjust the heating power of the gas heater 132, and adjust the temperature of the ejected gas to be maintained at 60-80°C. The hot gas spray head 134 is set in a diffusing state, and sprays a diffused hot air flow toward the solution in the upper part of the reaction chamber 100. It is worth noting that the distance between the hot gas spray head 134 and the solution surface 101 is less than or equal to 3 cm, so that the hot gas spray head 134 The ejected hot air heats the liquid on the surface of the solution surface 101, and particularly heats the liquid on the surface corresponding to the oxalic acid dropper 210, so that the oxalic acid solution and the catalyst are dropped into the reaction chamber 100 from the oxalic acid dropper 210 The active component solution A solution is quickly mixed uniformly, and under the promotion and stirring of hot air, the oxalic acid solution is promoted to be quickly mixed with the solution without local excess, and the efficiency of catalyst preparation is improved, and the preparation quality of the catalyst can be improved. Therefore, the stability of the prepared product and the performance of the product are ensured, and the dropped oxalic acid solution can be uniformly and rapidly mixed with the reaction solution.

[0071] In addition, it is worth noting that the side wall of the reaction chamber 100 is provided with a cold air nozzle 143, and the front end of the cold air nozzle 143 inserted into the reaction chamber 100 is provided with a cold air nozzle 144. The cold air nozzle 144 passes through the cold air nozzle 143 and the second gas tank. 141 is connected to form a cold air jet unit 140, the cold air nozzle 143 is provided with a gas cooler 142, the gas cooler 142 is used to cool the gas, and the cold air jet unit 140 is used to inject cooling gas into the reaction chamber 100; The cold gas spray head 144 is arranged obliquely upward, and the cooling gas is sprayed obliquely upward into the reaction chamber 100. The cold gas nozzle 144 is used to blow cooling gas into the reaction chamber 100, and the temperature of the cooling gas is 0 to 3°C; the cooling gas is used to cool the liquid in the reaction chamber 100, thereby ensuring the stability and performance of the prepared product At the same time, the sprayed cooling gas accelerates the stirring of the solution in the reaction chamber 100, thereby making the reaction more uniform, avoiding local overproduction, and thereby improving the mesoporous performance and catalytic performance of the catalyst.

[0072] It is worth noting that the distance between the hot air nozzle 134 and the solution level 101 is less than the distance between the cold air nozzle 144 and the solution level 101; that is, the level of the cold air nozzle 144 is lower than the level of the hot air nozzle 134, and the cold air nozzle 144 The inclination angle of the vertical direction is 30-60°. In addition, it is worth noting that the spraying speed of the cold gas spray head 144 is greater than that of the hot gas spray head 134. The spray speed of the hot gas spray head 134 should be controlled so that the hot gas spray head 134 does not splash the surface liquid.

[0073] The lower part of the reaction chamber 100 is provided with a stirring part 120, which is used to stir the solution in the reaction chamber 100. When the stirring part 120 rotates to the vertical direction, the top of the stirring part 120 and the hot gas nozzle 134 are on the same horizontal line. The joint action of the stirring component 120 and the cold air nozzle 144 improves the uniformity of mixing. In addition, a water inlet 111 is provided at the bottom of one side of the ice water bath 110, and a water outlet 112 is provided on the top of the other side of the ice water bath 110. The ice water flows into the ice water bath 110 through the water inlet 111 and flows out from the water outlet 112. Therefore, the cooling effect of the ice water bath 110 on the reaction cavity 100 is improved.

[0074] Example 3

[0075] The basic content of this embodiment is the same as that of embodiment 1, the difference is: in step 400, the catalyst preparation process, the additive is added to the calcined product, and then the mixture of the calcined product and the additive is added to the grinding device 40 for grinding Among them, the additives include potassium permanganate or potassium manganate. Potassium permanganate or potassium manganate can decompose oxygen and manganese oxide under heating conditions. Oxygen is good for the catalytic effect, and manganese oxide is good for supplementing the consumption of catalyst manganese.