Method for producing activated carbon carrier loaded with heat accumulator and exhaust gas treatment method

Abstract

The application provides a preparation method of a heat storage active carbon carrier and a waste gas treatment method, and the preparation method of the heat storage active carbon carrier comprises the following steps: preparing a heat storage sol, mixing heat storage powder, a corrosion inhibitor and water to obtain a mixed solution; coating the sol on the surface of the active carbon, and making the sol fill the pores on the surface of the active carbon; after standing for a certain time, removing the residual sol in the pores; and drying the sol, drying the active carbon after the coating of the sol is completed at a set temperature to obtain the active carbon carrier. The heat storage ceramic is loaded on the active carbon, the heat storage ceramic can improve the temperature of the carrier by absorbing the energy released in the catalytic oxidation reaction, the moisture in the waste gas can be reduced in the heating process of the cold waste gas, and therefore the influence of water on the performance of the catalyst can be avoided, and good environmental, economic and social benefits are achieved.

Description

Technical Field

[0001] This invention relates to the field of industrial waste gas treatment technology, and in particular to a method for preparing an activated carbon carrier for a heat storage body and a waste gas treatment method. Background Technology

[0002] In industrial waste gas treatment, commonly used processes include activated carbon adsorption and catalytic oxidation. A combination of activated carbon adsorption, hot gas desorption, and catalytic oxidation is used to purify organic waste gas. Activated carbon's micropores and high surface tension are utilized to adsorb organic solvents in the waste gas, thus purifying the discharged waste gas.

[0003] In the aforementioned activated carbon adsorption process, activated carbon is a porous carbonaceous material with a well-developed pore structure, large specific surface area, and a wide distribution of surface functional groups. It can effectively adsorb various VOCs in waste gas, making it an excellent adsorbent. The adsorption area of ​​each gram of activated carbon is equivalent to that of eight tennis courts. Activated carbon adsorption is achieved through a combination of physical and chemical adsorption forces. Besides carbon, its constituent substances include small amounts of hydrogen, nitrogen, oxygen, and ash. The structure of activated carbon consists of stacked hexagonal carbon rings. The irregular arrangement of these hexagonal carbon rings results in the high micropore volume and large surface area characteristic of activated carbon. Activated carbon can be made from many carbonaceous materials, including wood, sawdust, coal, coke, peat, lignin, fruit pits, nutshells, sugarcane pulp, bone, lignite, and petroleum residues. Among these, coal and coconut shells have become the most commonly used raw materials for manufacturing activated carbon. Activated carbon is an excellent adsorbent with a well-developed internal pore structure and a huge specific surface area. It has been widely used in industrial wastewater, waste gas and air purification devices, as well as in industries such as organic synthesis, food and medicine. It is also used in military and high-tech industries.

[0004] In the aforementioned catalytic oxidation process, water can affect the catalyst in several ways. Firstly, hydrogen bonding may occur between water molecules and the catalyst, reducing the ability of reactant molecules at the catalyst's active sites to form electrostatic interactions with hydrogen ions, thus decreasing catalyst efficiency. Secondly, water molecules can compete with reactant molecules at the active sites for adsorption sites, thereby reducing the apparent concentration of reactant molecules on the catalyst and consequently decreasing the reaction rate. Furthermore, water molecules may affect the equilibrium of the oxidation state on the catalyst surface, altering the activation energy or zero-point energy of reactant molecules, thus impacting the adsorption, diffusion, and reaction steps of the reactant molecules.

[0005] Activated carbon made from different raw materials has different pore sizes. Activated carbon made from coconut shells has the smallest pore radius. Wood-based activated carbon generally has the largest pore radius; it is used to adsorb larger molecules and is almost exclusively used in the liquid phase. Coal-based activated carbon has a pore size between the two. However, activated carbon easily absorbs water during adsorption processes, which in turn makes the catalyst performance susceptible to the effects of water during the catalytic oxidation reaction of waste gas.

[0006] The specific harms of water molecules to catalysts include: 1. Deactivation of catalyst active sites: Water molecules may react with the active sites of the catalyst, causing degradation or deactivation, thus affecting the efficiency and stability of the catalyst. 2. Reduction of reactant molecule concentration on the catalyst surface: Water molecules compete for adsorption sites of reactant molecules, leading to a decrease in the apparent concentration of reactant molecules on the catalyst surface, thus affecting the reaction rate. 3. Impact on reaction condition control: The presence of water may make reaction conditions difficult to control, causing the catalyst to lose its ability to control the reaction process.

[0007] It should be noted that the information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide a method for preparing an activated carbon carrier for a heat storage body, so as to solve the problem that activated carbon easily absorbs water during waste gas treatment, and the water affects the catalytic performance.

[0009] To solve the above technical problems, the present invention provides a method for preparing an activated carbon carrier for a heat storage body, comprising:

[0010] The preparation of the heat storage body sol involves mixing heat storage body powder, corrosion inhibitor and water to obtain a mixture, heating and stirring the mixture at a set temperature, adding concentrated acid dropwise to the mixture until the mixture becomes viscous, and then cooling and allowing it to stand to obtain the sol.

[0011] Sol coating involves coating the activated carbon surface with sol, ensuring that the sol fills the pores on the activated carbon surface, and then removing the residual sol from the pores after a certain period of time.

[0012] Drying the sol involves drying the activated carbon after the sol coating is applied at a set temperature for a certain period of time to obtain the activated carbon carrier.

[0013] Preferably, prior to the preparation of the heat storage sol, the method for preparing the activated carbon carrier supporting the heat storage further includes:

[0014] Activated carbon cleaning involves soaking the activated carbon in acid solution, then rinsing it with deionized water and drying it for later use.

[0015] Preferably, after the sol is dried, the method for preparing the activated carbon carrier of the heat storage body further includes:

[0016] Calcination: The activated carbon carrier is calcined at a set temperature for a certain period of time.

[0017] Thermal decomposition involves placing the calcined activated carbon carrier in an inert gas environment and thermally decomposing it for a certain period of time at a set temperature.

[0018] Preferably, the roasting includes:

[0019] The carrier was continuously calcined at 550±5℃ for 6 hours or more;

[0020] The thermal decomposition includes:

[0021] The calcined carrier was thermally decomposed in a nitrogen atmosphere at a temperature of 550±5℃ for at least 6 hours.

[0022] Preferably, the step of mixing the heat storage powder, corrosion inhibitor, and water to obtain the mixture comprises:

[0023] The heat storage element is crushed and sieved to obtain heat storage element powder;

[0024] The heat storage powder and the corrosion inhibitor are mixed at a mass ratio within a first set range to obtain a mixture;

[0025] The mixture is mixed with water according to the second set mass ratio to obtain a mixture.

[0026] Preferably, the mass ratio of the first set range is 1 to 4:1, and the mass ratio of the second set range is 1:2.

[0027] Preferably, the drying of the sol includes:

[0028] After the sol coating is completed, the activated carbon is dried at 105℃~250℃ for 2 hours or more.

[0029] Preferably, the heat storage body is a heat storage ceramic.

[0030] Preferably, the corrosion inhibitor is sodium ethylenediaminetetramethylenephosphonate.

[0031] Based on the same inventive concept, the present invention also provides a waste gas treatment method, including a method for preparing the activated carbon carrier of the above-mentioned load heat storage body.

[0032] Compared with the prior art, the method for preparing the activated carbon carrier of the supported heat storage body of the present invention has the following advantages:

[0033] This invention involves preparing a heat storage sol by mixing heat storage powder, corrosion inhibitor, and water to obtain a mixture. The mixture is then heated and stirred at a set temperature. Concentrated acid is added dropwise until the mixture becomes viscous. After cooling and settling, a sol is obtained. The sol is then coated onto the surface of activated carbon, filling the pores of the activated carbon surface. After settling for a certain period, any remaining sol in the pores is removed. Finally, the sol is dried at a set temperature for a certain period to obtain an activated carbon carrier. Therefore, the activated carbon carrier provided by this invention, due to the heat storage ceramic loaded on the activated carbon, can increase the carrier temperature by absorbing the energy released by the catalytic oxidation reaction. When cold waste gas passes through the hot heat storage ceramic, the heat storage ceramic releases the stored heat, heating the cold waste gas to the required preheating temperature. During the heating process, the moisture content of the waste gas is reduced, thus preventing water from affecting the catalyst performance. Because of the sufficient cross-sectional area of ​​the geometric structure of thermal storage ceramics, which enables uniform distribution of waste gas and low resistance, thermal storage ceramics also have a large specific surface area, ensuring a large effective heat transfer area. Furthermore, thermal storage ceramics are inexpensive and have a long service life. Therefore, activated carbon carriers not only possess excellent adsorption capacity but also offer significant environmental, economic, and social benefits.

[0034] The waste gas treatment method provided by this invention and the method for preparing the activated carbon support for the heat storage body provided by this invention belong to the same inventive concept. Therefore, the waste gas treatment method provided by this invention has at least all the advantages of the method for preparing the activated carbon support for the heat storage body provided by this invention, which will not be elaborated here. Furthermore, since the support prepared by the method for preparing the activated carbon support for the heat storage body provided by this invention can reduce the moisture content in the waste gas and reduce the impact of moisture on the catalyst, the waste gas treatment method provided by this invention can improve the efficiency of catalytic oxidation of the waste gas after adsorption, thereby improving the efficiency of waste gas treatment. Attached Figure Description

[0035] Figure 1 This is a flowchart of a method for preparing an activated carbon carrier for a heat storage body according to one embodiment of the present invention. Detailed Implementation

[0036] To make the objectives, advantages, and features of the present invention clearer, the following further elaborates on the preparation method of the activated carbon carrier of the load heat storage body proposed by the present invention in combination with the attached drawings and specific embodiments. It should be noted that the attached drawings are in very simplified forms and are all drawn with non-precise scales, only for conveniently and clearly assisting in explaining the objectives of the embodiments of the present invention. It should be understood that the drawings in the specification do not necessarily show the specific structure of the present invention in proportion, and the illustrative features used to explain certain principles of the present invention in the drawings of the specification will also adopt a slightly simplified drawing method. The specific design features of the present invention disclosed herein, such as specific dimensions, directions, positions, and shapes, will be partially determined by the specific application and usage environment. Also, in the following described embodiments, sometimes the same reference numerals are used commonly between different drawings to represent the same part or parts with the same functions, and the repeated description thereof is omitted. In this specification, similar reference numerals and letters are used to represent similar items. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0037] In addition, in the description of the present invention, the meaning of "plural" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0038] In the description of this specification, the descriptions referring to terms such as "exemplarily" and "specifically" mean that the specific features, structures, materials, or characteristics described in connection with this embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0039] Refer Figure 1 A specific implementation of the preparation method of an activated carbon carrier of a load heat storage body is disclosed. The preparation method of the activated carbon carrier of the load heat storage body specifically includes steps S1 to step S6.

[0040] Step S1: Activated carbon cleaning. After soaking the activated carbon in acid solution, it is washed with deionized water and dried for later use.

[0041] Specifically, refer Figure 1As shown, take an appropriate amount of activated carbon and place it in a container. Add dilute nitric acid to the container, ensuring the activated carbon is completely submerged, to soak it and remove impurities and heavy metals from its surface. The soaking time is 10 minutes or more. The concentration of the dilute nitric acid is 1 mol / L. After soaking, rinse the activated carbon surface with deionized water to remove the dilute nitric acid. To thoroughly rinse the activated carbon surface, rinse it multiple times with deionized water. It should be noted that the acid solution can be dilute nitric acid, dilute sulfuric acid, or dilute hydrochloric acid, as long as it can remove impurities and heavy metals from the activated carbon surface. In this embodiment, dilute nitric acid is preferred. Next, place the washed activated carbon in an oven and dry it at 105℃~250℃ for 2 hours or more. The dried activated carbon is then ready for use.

[0042] Step S2: Preparation of heat storage body sol. Heat storage body powder, corrosion inhibitor and water are mixed to obtain a mixture. The mixture is heated and stirred at a set temperature. Concentrated acid is added dropwise to the mixture until the mixture becomes viscous. After cooling and standing, a sol is obtained.

[0043] Specifically, continue to participate Figure 1 As shown, the heat storage medium is a very important material in the incinerator. Its working principle is as follows: when cold gas passes through the hot heat storage medium, the heat storage medium releases the stored heat. When the waste gas passes through the heat storage medium, the waste gas can be heated to the required preheating temperature. The heat storage medium itself is cooled (called: cold cycle). The preheated waste gas enters the combustion chamber. After reaction, the hot purified gas passes through the cold heat storage medium. The heat storage medium absorbs the heat of the purified gas, so that the waste gas is cooled and the heat storage medium itself is heated (called: hot cycle). The characteristics of the heat storage medium are: (1) high temperature resistance. (2) high density and high specific heat capacity. (3) good heat transfer performance and excellent thermal conductivity and thermal radiation, that is, it can quickly transfer heat to the colder waste gas during the cold cycle; and can quickly absorb the heat of the purified gas during the hot cycle. (4) good shock resistance. (5) sufficient mechanical strength at high temperature. (6) high temperature oxidation resistance and chemical corrosion resistance. (7) The geometry of the heat storage body should have sufficient flow cross-sectional area, and have characteristics such as uniform gas distribution and low resistance, and have as large a specific surface area as possible to ensure that the heat storage body has a large effective heat transfer area. (8) The price should be as low as possible, while the service life should be long.

[0044] The heat storage medium can be heat storage ceramics, polymer heat storage materials (such as polylactic acid (PLA)), etc. In this embodiment, heat storage ceramics are preferred as the heat storage medium. The heat storage ceramics are selected, pulverized, and sieved. Powder from heat storage ceramics with a particle size smaller than 60 mesh is reserved for later use. The corrosion inhibitor can be an organic corrosion inhibitor (such as sodium ethylenediaminetetramethylenephosphonate), an inorganic corrosion inhibitor (such as nitrates and nitrites), or a composite corrosion inhibitor (such as a composite corrosion inhibitor of organophosphates and epoxy resins), etc. In this embodiment, sodium ethylenediaminetetramethylenephosphonate is preferred as the corrosion inhibitor. The following will illustrate this embodiment using heat storage ceramics as the heat storage medium and sodium ethylenediaminetetramethylenephosphonate as the corrosion inhibitor as an example.

[0045] In step S2, firstly, heat-storing ceramic powder and sodium ethylenediaminetetramethylenephosphonate are weighed and mixed at a mass ratio of 1 to 4:1 to obtain a mixture. The mixture is placed in a preparation container. Water is added to the preparation container, and the mixture and water are mixed at a mass ratio of 1:2. Then, the preparation container is placed in a water bath and heated and stirred at 50°C to 80°C, preferably at 60°C. During stirring, concentrated nitric acid is added dropwise to the preparation container until the mixture begins to become viscous. Finally, the mixture with added concentrated nitric acid is cooled and allowed to stand to obtain a sol. The concentrated nitric acid is 68% nitric acid by mass.

[0046] Step S3: Coat the activated carbon surface with sol, ensuring that the sol fills the pores on the activated carbon surface. After standing for a certain period of time, remove the residual sol from the pores.

[0047] Specifically, continue to participate Figure 1 As shown, the sol is drawn up with a dropper and coated onto the dried activated carbon. The sol-coated activated carbon is then placed in the funnel of a vacuum filtration device. The vacuum filtration device is turned on, creating a negative pressure in the funnel. Under this negative pressure, the sol flows into the numerous pores on the surface of the activated carbon. The activated carbon is then inverted, and the vacuum filtration device is turned on again, causing the sol to flow along the surface of the activated carbon into the pores once more. To ensure a uniform coating of sol within the pores of the activated carbon, the sol-coated activated carbon can be repeatedly placed in the funnel of the vacuum filtration device, repeating the above operation. After the activated carbon is coated with the sol, it should be allowed to stand for 10 minutes. Then, an air-blowing device, such as a bulb syringe, should be used to blow out any remaining sol from the pores to prevent clogging and ensure proper adsorption. It should be noted that the above-mentioned vacuum filtration device is existing technology, and its specific structure and principle are already familiar to those skilled in the art, so it will not be described in detail here. In addition, the specific negative pressure of the vacuum filtration device is only required to make the sol flow into the pores on the surface of the activated carbon. The specific negative pressure of the vacuum filtration device can be set according to the actual operation, and no specific requirements are made here.

[0048] The activated carbon carrier provided in this embodiment features a heat-storing ceramic loaded on the activated carbon. The heat-storing ceramic absorbs the energy released by the catalytic oxidation reaction, raising the carrier's temperature. When cold waste gas passes through the hot heat-storing ceramic, the ceramic releases its stored heat, heating the waste gas to the required preheating temperature. During the heating process, the moisture content of the waste gas is reduced, thus preventing water from affecting the catalyst's performance. The heat-storing ceramic's geometric structure provides sufficient flow cross-sectional area, ensuring uniform waste gas distribution and low resistance. Furthermore, the heat-storing ceramic has a large specific surface area, ensuring a large effective heat transfer area. It is also inexpensive and has a long service life. Therefore, this activated carbon carrier not only possesses excellent adsorption capacity but also offers significant environmental, economic, and social benefits.

[0049] Step S4: Drying the sol. After the sol is coated, the activated carbon is dried at a set temperature for a certain period of time to obtain the activated carbon carrier.

[0050] Specifically, continue to participate Figure 1 As shown, after the sol coating is completed, the activated carbon is placed in an oven and dried at 105℃~250℃ for 2 hours or more to dry the sol. After drying, the activated carbon carrier is obtained. When using this activated carbon carrier to adsorb and treat waste gas, the heat storage ceramic loaded on the activated carbon carrier absorbs the energy released by the catalytic oxidation reaction, which can increase the temperature of the activated carbon carrier. When the cold waste gas passes through the hot heat storage ceramic, the heat storage ceramic releases the stored heat, so that the cold waste gas is heated to the required preheating temperature. During the heating process, the moisture in the waste gas can be reduced, thereby avoiding the influence of water on the performance of the catalyst.

[0051] Step S5: Calcination, the activated carbon carrier is calcined at a set temperature for a certain time.

[0052] Specifically, continue to participate Figure 1 As shown, to improve the stability and performance of the activated carbon carrier, the dried activated carbon carrier from step S4 is placed in a muffle furnace and calcined at 550±5℃ for 6 hours or more. This improves the physical properties of the sol-coated activated carbon carrier, removes volatile substances and impurities, and enhances its stability and durability. The muffle furnace is heated at a rate of 3℃ to 10℃ per minute to avoid excessive heating that could damage the activated carbon carrier.

[0053] Step S6: Thermal decomposition, the calcined activated carbon carrier is thermally decomposed at a set temperature for a certain period of time.

[0054] Specifically, continue to participate Figure 1As shown, the calcined activated carbon support is placed in a tube furnace and heated at 550±5℃ for 6 hours or more under inert gas protection to obtain an activated carbon support loaded with heat storage ceramics. Continuous heating decomposes impurities on the support surface. The tube furnace heats up at a rate of 3℃ to 10℃ per minute, which also protects the activated carbon support through stable heating.

[0055] In summary, the activated carbon support prepared in this embodiment, due to the presence of a heat-storing ceramic loaded on it, absorbs the energy released by the catalytic oxidation reaction, thereby increasing the temperature of the support. When cold waste gas passes through the hot heat-storing ceramic, the ceramic releases its stored heat, heating the waste gas to the required preheating temperature. During the heating process, the moisture content of the waste gas is reduced, thus preventing water from affecting the catalyst performance. The geometric structure of the heat-storing ceramic provides sufficient flow cross-sectional area, resulting in uniform waste gas distribution and low resistance. Furthermore, the heat-storing ceramic has a large specific surface area, ensuring a large effective heat transfer area. It is also inexpensive and has a long service life. Therefore, the activated carbon support not only possesses excellent adsorption capacity but also offers significant environmental, economic, and social benefits.

[0056] This invention also discloses a waste gas treatment method, in which waste gas is adsorbed onto a carrier prepared using the above-described method for preparing an activated carbon carrier with a supported heat storage body. The adsorbed waste gas is then subjected to catalytic oxidation treatment.

[0057] The waste gas treatment method provided in this embodiment belongs to the same inventive concept as the method for preparing the activated carbon support for the heat storage body provided in the above embodiments. Therefore, the waste gas treatment method provided in this embodiment has at least all the advantages of the method for preparing the activated carbon support for the heat storage body provided in the above embodiments, which will not be repeated here. Furthermore, since the support prepared by the method for preparing the activated carbon support for the heat storage body provided in the above embodiments can reduce the moisture content in the waste gas and reduce the impact of moisture on the catalyst, the waste gas treatment method provided in this embodiment can improve the efficiency of catalytic oxidation of the waste gas after adsorption, thereby improving the efficiency of waste gas treatment.

[0058] In summary, the above embodiments have provided detailed descriptions of different configurations of the preparation method of the activated carbon carrier for the heat storage body. Of course, the above descriptions are only descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention in any way. The present invention includes but is not limited to the configurations listed in the above embodiments. Those skilled in the art can draw inferences from the above embodiments. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method for preparing an activated carbon carrier for supporting a heat storage body, characterized in that, include: The preparation of the heat storage body sol involves mixing heat storage body powder, corrosion inhibitor and water to obtain a mixture, heating and stirring the mixture at a set temperature, adding concentrated acid dropwise to the mixture until the mixture becomes viscous, cooling and allowing it to stand to obtain a sol. The heat storage body is a heat storage ceramic and the corrosion inhibitor is sodium ethylenediaminetetramethylenephosphonate. Sol coating involves coating the activated carbon surface with sol, ensuring that the sol fills the pores on the activated carbon surface, and then removing the residual sol from the pores after a certain period of time. Drying the sol involves drying the activated carbon after the sol coating is applied at a set temperature for a certain period of time to obtain the activated carbon carrier.

2. The method for preparing the activated carbon carrier for the supported heat storage body according to claim 1, characterized in that, Prior to the preparation of the heat storage sol, the method for preparing the activated carbon carrier supporting the heat storage further includes: Activated carbon cleaning involves soaking the activated carbon in acid solution, then rinsing it with deionized water and drying it for later use.

3. The method for preparing the activated carbon carrier for the supported heat storage body according to claim 1, characterized in that, After the sol is dried, the method for preparing the activated carbon carrier of the heat storage body further includes: Calcination: The activated carbon carrier is calcined at a set temperature for a certain period of time. Thermal decomposition involves placing the calcined activated carbon carrier in an inert gas environment and thermally decomposing it for a certain period of time at a set temperature.

4. The method for preparing the activated carbon carrier for the supported heat storage body according to claim 3, characterized in that, The roasting includes: The activated carbon carrier is continuously calcined at 550±5℃ for 6 hours or more; The thermal decomposition includes: The calcined activated carbon carrier was thermally decomposed in a nitrogen atmosphere at a temperature of 550±5℃ for 6 hours or more.

5. The method for preparing the activated carbon carrier for the supported heat storage body according to claim 1, characterized in that, The process of mixing the heat storage powder, corrosion inhibitor, and water to obtain the mixture includes: The heat storage element is crushed and sieved to obtain heat storage element powder; The heat storage powder and the corrosion inhibitor are mixed at a mass ratio within a first set range to obtain a mixture; The mixture is mixed with water according to the second set mass ratio to obtain a mixture.

6. The method for preparing the activated carbon carrier for the supported heat storage body according to claim 5, characterized in that, The mass ratio of the first set range is 1 to 4:1, and the mass ratio of the second set range is 1:

2.

7. The method for preparing the activated carbon carrier for the supported heat storage body according to claim 1, characterized in that, The drying of the sol includes: After the sol coating is completed, the activated carbon is dried at 105℃~250℃ for 2 hours or more.

8. A method for treating waste gas, characterized in that, include: The waste gas is adsorbed by a carrier prepared using the method for preparing an activated carbon carrier for a load heat storage body as described in any one of claims 1-7. The adsorbed waste gas is then subjected to catalytic oxidation treatment.

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