Nanometer zinc oxide desulfurizer and its preparation method

Abstract

The application provides a nano-zinc oxide desulfurizer and a preparation method thereof. The raw materials of the nano-zinc oxide desulfurizer include modified nano-zinc oxide 60-75 parts by weight, a binder 5-10 parts by weight and a filler 10-30 parts by weight. Sodium carbonate and activated carbon fiber powder are loaded into the pores of the nano-zinc oxide by impregnation, so as to enhance the sulfur capacity and desulfurization precision of the nano-zinc oxide. The metal oxide filler is attached to the nano-zinc oxide, so as to enhance the low-temperature resistance of the nano-zinc oxide desulfurizer. The modified nano-zinc oxide, the binder and the filler are prepared into the nano-zinc oxide desulfurizer by dry mixing and grinding. The obtained nano-zinc oxide desulfurizer has high sulfur capacity, high desulfurization precision and high desulfurizer activity. The preparation process is simple, the loss of raw materials is small, and the nano-zinc oxide desulfurizer has a good development prospect.

Description

Technical Field

[0001] This invention relates to the field of desulfurizing agent technology, and in particular to a nano zinc oxide desulfurizing agent and its preparation method. Background Technology

[0002] With the increasing severity of global climate change and environmental pollution, environmental protection has become a global focus. Desulfurization refers to the process of removing sulfides from gases or liquids containing high concentrations of sulfides. Desulfurization processes are mainly applied in industrial processes such as petroleum refining, natural gas processing, and coal combustion. As an important technological means to reduce sulfur dioxide emissions, desulfurization is of great significance for environmental protection. Desulfurization processes involve using chemical or physical methods to convert sulfur dioxide in flue gas into other substances, thereby reducing or eliminating its impact on the environment.

[0003] Desulfurizers are primarily used in industrial processes to remove free sulfur or sulfur compounds from fuels, raw materials, or other materials. In environmental protection, they are mainly used to remove sulfur oxides, such as sulfur dioxide (SO2) and sulfur trioxide (SO3), from waste gases. Common desulfurizers include alkaline compounds such as lime, limestone, sodium carbonate, and basic aluminum sulfate, as well as certain special composite desulfurizers, such as calcium manganese alloys. Desulfurizers not only help reduce scaling and corrosion in equipment but also improve the reliability and stability of desulfurization systems. Furthermore, desulfurizers can increase the concentration of calcium ions in liquid solutions, accelerating the crystallization rate of sulfate ions, thereby improving desulfurization efficiency. They work by reducing the surface tension between gas and liquid, increasing the rate of gas diffusion into liquid, and altering the properties of calcium sulfate crystals to prevent crystal deposition in nozzles and other areas. In practical applications, appropriate desulfurizers can be selected based on different operating conditions to meet the desulfurization needs of various environments. For example, the solid desulfurizer iron oxide red can be used for desulfurization in an oxygen-free environment, while calcium manganese alloys are an ideal composite deoxidizer and desulfurizer suitable for the production of steel and other alloys. The use of desulfurizing agents can not only reduce or disable some auxiliary facilities, such as slurry circulation pumps and oxidation fans, but also improve desulfurization efficiency, reduce operating costs, and create significant economic and social benefits.

[0004] Zinc oxide desulfurizer, with zinc oxide as its main component, is a conversion and absorption type solid desulfurizer. In zinc oxide desulfurization, H2S molecules in the feed gas diffuse from the bulk gas flow to the outer surface of the desulfurizer. H2S then diffuses into the pores of the desulfurizer particles. On the surface of the desulfurizer, H2S reacts with ZnO to form ZnS. However, denser particles reduce pore size and volume. Lowering the temperature, increasing the space velocity, and increasing the water vapor content all decrease the sulfur capacity. The form and concentration of sulfides in the process gas also have a certain impact on the sulfur capacity. Zinc oxide desulfurization has very low operating costs, does not cause secondary pollution, and does not pollute the environment. Therefore, zinc oxide desulfurizer has a promising future in desulfurization technology. In practical applications, appropriate desulfurizers can be selected according to different operating conditions to meet the desulfurization needs of different environments.

[0005] Currently, patent publication number "CN 105692685A" discloses a zinc oxide desulfurizing agent and its preparation method. By using a mixture of ammonium bicarbonate and ammonium carbonate as a precipitant, the desulfurization performance of the desulfurizing agent is improved; however, it does not improve the sulfur capacity of the zinc oxide desulfurizing agent. Patent publication number "CN 1895743A" discloses a nano desulfurizing agent for gas desulfurization, its preparation method, and its application. This patent uses zinc nitrate and ferric nitrate as zinc and iron sources, and citric acid, aminoacetic acid, or urea as gelling agents. The obtained gel is heated to a certain temperature for auto-ignition, and then calcined at high temperature to obtain a powdered desulfurizing agent. Finally, it is calcined at high temperature to obtain the desulfurizing agent. This preparation method is complex and time-consuming in the preparation process. For example, the zinc sol needs to be refluxed and filtered to obtain the product, which is not easy to industrialize.

[0006] In view of the problems existing in the prior art, this application aims to solve the problems of low sulfur capacity, low desulfurization accuracy, insufficient desulfurization activity, and inability to simultaneously remove hydrogen sulfide and organic sulfur in zinc oxide desulfurizers, which seriously limit their industrial application. Summary of the Invention

[0007] Purpose of the invention: The purpose of this invention is to provide a nano zinc oxide desulfurizer and its preparation method, which improves the problems of low sulfur capacity, low desulfurization accuracy, insufficient desulfurizer activity, and inability to simultaneously remove hydrogen sulfide and organic sulfur in zinc oxide desulfurizers.

[0008] The technical solution of the present invention: A nano zinc oxide desulfurizing agent, wherein the components of the nano zinc oxide desulfurizing agent, by weight, include: 60-75 parts of modified nano zinc oxide, 5-10 parts of binder, and 10-30 parts of filler.

[0009] Furthermore, the modified nano zinc oxide is prepared by modifying nano zinc oxide, activated carbon fiber powder, and sodium carbonate solution.

[0010] The preparation method of the modified nano zinc oxide includes the following steps: (1) Add activated carbon fiber powder to sodium carbonate solution and stir evenly to obtain a mixed solution; (2) Add nano zinc oxide to the mixed solution obtained in step (1), stir evenly, filter, and let stand for a period of time to obtain a mixture; (3) The mixture obtained in step (2) is placed in a high temperature oven at 100~120℃ and baked to obtain modified nano zinc oxide.

[0011] Furthermore, the amount of activated carbon fiber powder is 10-15% of the mass of nano zinc oxide.

[0012] Furthermore, the mass concentration of the sodium carbonate solution is 3-20%.

[0013] Furthermore, the adhesive is one or more of carboxymethyl cellulose, kaolin, clay, starch, and gum.

[0014] Furthermore, the filler is one or more of copper oxide, copper nitrate, cobalt nitrate, and nickel oxide.

[0015] This invention also provides a method for preparing a nano-zinc oxide desulfurizing agent, characterized by comprising the following steps: Step 1: Weigh the modified nano zinc oxide, binder, and filler according to the proportions, mix them evenly, and then add water to thoroughly mix them. Step 2: Extrude the material obtained in Step 1 into a mold, and then cure the material after extrusion. Step 3: The cured material is evenly distributed in the firing basket, and the firing basket is transferred to the roller kiln for firing through the transmission device to obtain nano zinc oxide desulfurizer.

[0016] Furthermore, the mixing and grinding adopts a high-speed roller mill with a discharge flow rate of 0.5~1t / h; the extrusion molding adopts a four-column hydraulic press; the curing is to stand at 70~80℃ for 18~30h; and the calcination temperature in the roller kiln is 1200~1400℃ for 12~24h.

[0017] Furthermore, the roller kiln is divided into a transport area, a feeding area, and a packaging area. In the transport area, the burning basket is transferred to the roller kiln for firing via a transmission device. A bottom support is installed below the transmission device, and the burning basket can hold materials. A feeding machine is installed in the feeding area, and an automatic unloading device is installed in the packaging area.

[0018] In the preparation process of nano zinc oxide desulfurizer, four high-speed roller mills are used to fully mix 2 tons of material within half an hour. After uniform mixing, the material is conveyed to three four-column hydraulic presses through a transmission device to extrude the material into shape according to the diameter required by the customer. Due to uneven moisture distribution, if the material is directly fed into the roasting kiln, it will affect the quality of the finished product, resulting in low zinc oxide content, poor appearance, and low desulfurization activity. Therefore, after extrusion molding, the material is cured. The cured material is placed in plastic baskets, stacked on pallets, and transported by forklift. After being transported to the curing area, it is left to stand naturally for 24 hours. After curing, the material is transported to the material distribution area by forklift, where workers evenly distribute the material in the plastic baskets into the firing baskets. The firing baskets are then transported to the roller kiln for roasting through a transmission device. After roasting, the material is conveyed to the discharge port, where workers remove the firing baskets and pour the desulfurizer into ton bags. Each firing pan can hold about 10 kg of desulfurizer, and the output per shift is 4-5 tons.

[0019] First, a material feeder is installed in the feeding area of ​​the roller kiln, eliminating the need for manual feeding; workers simply pour the material onto the feeder. Second, an automatic unloading device is installed in the packaging area, eliminating the need for workers to remove the burning baskets and pour the desulfurizing agent into ton bags. The finished product is directly unloaded into the ton bags via the automatic unloading device. Workers only need to control the weight of the ton bags, seal them, and then use an overhead crane to transport the ton bags to the finished product area. Third, to address the loss of desulfurizing agent during transmission, a bottom support is installed under the main transmission device to facilitate the collection of abrasive powder. The entire preparation process is simple, with minimal raw material loss, and has promising production prospects.

[0020] Beneficial effects: The nano zinc oxide desulfurizer provided by this invention has high sulfur capacity, high desulfurization precision, and high low-temperature activity. The preparation process of the nano zinc oxide desulfurizer is simple, requires less manpower, and can reduce the loss of raw materials, thus having good development prospects. Detailed Implementation

[0021] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0022] Unless otherwise specified, all chemical reagents used in this invention are commercially available analytical grade reagents.

[0023] Modified nano zinc oxide A: (1) Add 2 kg of activated carbon fiber powder to 20 L of 10% sodium carbonate solution and stir evenly to obtain a mixed solution; (2) Add 20 kg of nano zinc oxide to the mixed solution obtained in step (1), stir evenly, filter, and let stand for 24 h to obtain the mixture; (3) The mixture obtained in step (2) is placed in a high temperature oven at 110°C and baked for 24 hours to obtain modified nano zinc oxide A.

[0024] Modified nano zinc oxide B: (1) Add 10 kg of activated carbon fiber powder to 20 L of 10% sodium carbonate solution and stir evenly to obtain a mixed solution; (2) Add 20 kg of nano zinc oxide to the mixed solution obtained in step (1), stir evenly, filter, and let stand for 24 h to obtain the mixture; (3) The mixture obtained in step (2) is placed in a high temperature oven at 110°C and baked for 24 hours to obtain modified nano zinc oxide B.

[0025] Modified nano zinc oxide C: (1) Add 2 kg of activated carbon fiber powder to 20 L of 25% sodium carbonate solution and stir evenly to obtain a mixed solution; (2) Add 20 kg of nano zinc oxide to the mixed solution obtained in step (1), stir evenly, filter, and let stand for 24 h to obtain the mixture; (3) The mixture obtained in step (2) is placed in a high temperature oven at 110°C and baked for 24 hours to obtain modified nano zinc oxide C.

[0026] Modified nano zinc oxide D: (1) Add 20 kg of nano zinc oxide to 20 L of 10% sodium carbonate solution, stir evenly, filter, and let stand for 24 h to obtain a mixture; (2) The mixture obtained in step (1) is placed in a high temperature oven at 110°C and baked for 24 hours to obtain modified nano zinc oxide D.

[0027] Modified nano zinc oxide E: (1) Add 3 kg of activated carbon fiber powder to 20 L of water and stir evenly to obtain a mixed solution; (2) Add 20 kg of nano zinc oxide to the mixed solution obtained in step (1), stir evenly, filter, and let stand for 24 h to obtain the mixture; (3) The mixture obtained in step (2) is placed in a high temperature oven at 110°C and baked for 24 hours to obtain modified nano zinc oxide.

[0028] Zinc oxide desulfurizer preparation method A: Step 1: Weigh the modified nano zinc oxide, binder, and filler according to the proportion, mix them evenly, add water and mix and grind, with a mixing flow rate of 1t / h. Step 2: Extrude the material obtained in Step 1 into a Φ0.8×2 cylindrical shape. After molding, cure the material by standing at 80℃ for 24 hours. Step 3: Evenly arrange the cured material in the firing frame, and transfer the firing frame to the roller kiln through the transmission device. Firing at 1400℃ for 12 hours yields nano zinc oxide desulfurizer.

[0029] Zinc oxide desulfurizer preparation method B: Step 1: Weigh the modified nano zinc oxide, binder, and filler according to the proportion, mix them evenly, add water and mix and grind, with a mixing flow rate of 1t / h. Step 2: Extrude the material obtained in Step 1 into a cylindrical shape with a diameter of Φ0.8×2. Step 3: The extruded material is evenly arranged in the firing frame, and the firing frame is transferred to the roller kiln through the transmission device. It is then fired at 1400℃ for 12 hours to obtain nano zinc oxide desulfurizer.

[0030] Examples 1-6 Examples 1-6 were prepared according to the above-described zinc oxide desulfurizer preparation method A. Table 1 shows the zinc oxide desulfurizer ingredient list for Examples 1-6.

[0031] Table 1. Ingredients of Modified Zinc Oxide Desulfurizers in Examples 1-6 Comparative Examples 1-6 Comparative Examples 1-5 were prepared according to preparation method A of nano zinc oxide desulfurizer, and Comparative Example 6 was prepared according to preparation method B of nano zinc oxide desulfurizer. Table 2 shows the ingredient list of zinc oxide desulfurizer for Comparative Examples 1-6.

[0032] Table 2. Ingredients of zinc oxide desulfurizers for Comparative Examples 1-6 Performance testing: In order to prove the technical effect of the nano zinc oxide desulfurizer described in this invention, the following experiments were designed to determine the performance of the nano zinc oxide desulfurizer described in Examples 1-6 and Comparative Examples 1-6.

[0033] The prepared nano-zinc oxide desulfurizer was ground into 40-60 mesh particles for hydrogen sulfide penetration testing. The conditions were as follows: sample tube inner diameter 6 mm, sample loading height 2 cm, gas flow rate 100 ml / min, experimental temperature 30℃, and experimental pressure atmospheric pressure. The inlet hydrogen sulfide concentration was 800 mg / m³. 3 The hydrogen sulfide concentration at the outlet is 0.15 mg / m³. 3The experiment was stopped when the hydrogen sulfide content in the gas was determined by gas chromatography, the breakthrough sulfur capacity was calculated by chemical analysis, the specific surface area of ​​the desulfurizing agent was determined by the BET method, and the crushing strength was determined by a particle strength tester.

[0034] Table 3: Performance Test Results As can be seen from Table 3, In the nano-zinc oxide desulfurizer prepared by this invention, the high-temperature reaction of nano-zinc oxide with sodium carbonate solution and activated carbon fiber powder results in a nano-zinc oxide desulfurizer with high sulfur capacity, high desulfurization precision, and high low-temperature activity. Specifically, comparing Example 4 with Example 2, it is evident that adding more activated carbon fiber powder to the modified nano-zinc oxide leads to a decrease in the specific area, crush resistance, and desulfurization rate of the prepared desulfurizer; comparing Example 5 with Example 2, it is evident that excessively high sodium carbonate solution concentration in the modified nano-zinc oxide leads to a decrease in the crush resistance and desulfurization rate of the prepared desulfurizer; comparing Comparative Example 1 with Example 2, it is evident that insufficient modified nano-zinc oxide content leads to lower sulfur capacity and desulfurization precision of the nano-zinc oxide desulfurizer; comparing Comparative Example 2 with Example 2, it is evident that not adding activated carbon fiber powder to the modified nano-zinc oxide results in a decrease in the specific area of ​​the prepared desulfurizer. The modified nano zinc oxide desulfurizer, without sodium carbonate solution, exhibits reduced specific area, decreased crush resistance, and reduced desulfurization rate. Comparisons 3 and 2 show that excessively high or low filler content leads to a reduction in specific area and crush resistance. Comparisons 6 and 2 indicate that nano zinc oxide desulfurizers prepared using different methods have lower sulfur capacity and desulfurization precision than those prepared using the method described in this application. Therefore, the preparation method of the nano zinc oxide desulfurizer in this application can effectively improve the desulfurizer's performance.

[0035] This invention can also be implemented in various other ways. Without departing from the spirit and essence of this invention, those skilled in the art can make various corresponding changes and modifications according to this invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A method for preparing a nano-zinc oxide desulfurizing agent, characterized in that, Includes the following steps: Step 1: Weigh the modified nano zinc oxide, binder, and filler according to the proportions, mix them evenly, and then add water to thoroughly mix them. Step 2: Extrude the material obtained in Step 1 into a mold, and then cure the material after extrusion. Step 3: Evenly distribute the cured material in the firing basket, and transfer the firing basket to the roller kiln for firing through the transmission device to obtain nano zinc oxide desulfurizer. The firing temperature inside the roller kiln is 1200~1400℃, and the firing time is 12~24h. The components of the nano zinc oxide desulfurizer, by weight, include: 60-75 parts of modified nano zinc oxide, 5-10 parts of binder, and 10-30 parts of filler. The modified nano zinc oxide is prepared by modifying nano zinc oxide, activated carbon fiber powder, and sodium carbonate solution. The filler is one or more of copper oxide, copper nitrate, cobalt nitrate, and nickel oxide; The method for preparing the modified nano zinc oxide includes the following steps: (1) Add activated carbon fiber powder to a sodium carbonate solution with a mass concentration of 3-20%, stir evenly to obtain a mixed solution, wherein the amount of activated carbon fiber powder is 10-15% of the mass of nano zinc oxide; (2) Add nano zinc oxide to the mixed solution obtained in step (1), stir evenly, filter, and let stand for a period of time to obtain a mixture; (3) The mixture obtained in step (2) is placed in a high temperature oven at 100~120℃ and baked to obtain modified nano zinc oxide.

2. The preparation method of the nano-zinc oxide desulfurizer according to claim 1, characterized in that, The adhesive is one or more of carboxymethyl cellulose, kaolin, clay, starch, and gum.

3. The preparation method of the nano-zinc oxide desulfurizer according to claim 1, characterized in that, The mixing and grinding process uses a high-speed roller mill with a discharge flow rate of 0.5~1t / h; the extrusion molding process uses a four-column hydraulic press; and the curing process involves standing at an ambient temperature of 70~80℃ for 18~30h.

4. The preparation method of the nano-zinc oxide desulfurizer according to claim 3, characterized in that, The roller kiln is divided into a transport area, a feeding area, and a packaging area. In the transport area, the burning basket is transferred to the roller kiln for firing via a transmission device. A bottom support is installed under the transmission device, and the burning basket can hold materials. A feeding machine is installed in the feeding area, and an automatic unloading device is installed in the packaging area.

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