Combustion-supporting ball for coal combustion and its manufacturing method and application

Abstract

The application provides a combustion-supporting ball for coal combustion, which comprises an aluminum foil shell and a filling wrapped inside, and the filling comprises an oxidant, an oxidizing agent, a bulking agent and a desulfurizing agent; in the combustion-supporting ball, the components comprise, in percentage by weight, 8-10% of the aluminum foil shell, 6-10% of aluminum powder, 35-51% of the oxidant, 13-23% of the oxidizing agent, 9-19% of the bulking agent and 3-13% of the desulfurizing agent; the oxidant is selected from CuO and / or Fe2O3; and the diameter of the combustion-supporting ball is 0.7-0.8 cm. The application also provides a manufacturing method and application of the combustion-supporting ball. The combustion-supporting ball has the advantages of simple and safe manufacturing process, convenient use, small adding amount in coal combustion, good adaptability to various coal types, etc., can ensure safety in actual production, greatly improve the combustion efficiency of coal and the combustion quality of coal, and has wide popularization and application prospect.

Description

Technical Field

[0001] This invention belongs to the field of coal combustion additive technology, and relates to a combustion-supporting ball for coal combustion and its manufacturing method, as well as the application of the combustion-supporting ball for coal combustion in coal combustion. Background Technology

[0002] Coal, as a primary energy source in my country and globally, often emits large amounts of smoke and toxic gases during combustion, causing a series of significant environmental problems. Sulfides and nitrogen oxides produced by coal-fired power plants not only severely impact the environment but also reduce the combustion quality of the coal itself. Furthermore, while coal is a major global energy source, it is also a non-renewable energy source. Therefore, how to improve the energy efficiency of coal while protecting the environment is a crucial issue that deserves serious attention.

[0003] Coal combustion additives are made from various chemical raw materials processed in specific proportions. They are primarily used to improve coal combustion efficiency and mitigate environmental pollution from the coal-fired industry. Coal combustion additives typically include oxidants, catalysts, desulfurizers, leavening agents, smoke suppressants, and other organic auxiliaries, each playing a different role. Oxidants provide more active oxygen during coal combustion, thereby improving combustion efficiency. Catalysts accelerate the rate of chemical reactions during coal combustion, speeding up the conversion and transfer of active oxygen. Leavening agents, such as industrial salt, can generate micro-explosions in the high-temperature zone of the furnace, thus cleaning impurities from the coal surface and reducing incomplete combustion. Desulfurizers, also called sulfur-fixing agents, react with sulfur oxides produced during coal combustion, preventing them from entering the atmosphere and causing ecological degradation.

[0004] Currently, researchers have conducted extensive research and made some progress on how to effectively improve coal combustion efficiency using coal additives. For example, patent CN114410362A uses biomass fuel as a coal additive. While the idea of ​​introducing renewable energy into non-renewable energy sources to improve the energy and environmental situation on a long-term scale is commendable, the ignition temperature of biomass fuel is much lower than that of coal, which can lead to boiler failure during prolonged temporary shutdowns. Patent CN103160356A focuses on nitrogen oxides, which are rarely addressed in current invention patents of this type. Although it improves the environmental protection of the coal-fired industry to some extent, it has a smaller impact on the energy utilization efficiency of coal, and the processing steps are relatively complex, which is not conducive to widespread adoption across the industry. Some studies have also used aluminum powder as an additive for combustion assistance. While it has economic and practical advantages, aluminum powder is a highly flammable and explosive powder with an extremely high explosion sensitivity, and the use of large amounts of aluminum powder in industrial production can easily lead to safety accidents.

[0005] Therefore, it is an urgent technical problem to be solved to provide a coal combustion additive that is simple to manufacture, low in cost, safe and convenient to use, and has high combustion-promoting efficiency. Summary of the Invention

[0006] One of the objectives of this invention is to provide a combustion-supporting ball for coal combustion that is simple in structure, low in cost, safe and convenient to use, and has high combustion-supporting efficiency.

[0007] The second objective of this invention is to provide a method for manufacturing combustion-supporting balls for coal combustion that is simple in manufacturing process, low in cost, safe and convenient to use, and has high combustion-supporting efficiency.

[0008] The third objective of this invention is to provide an application of a combustion-supporting ball for coal combustion.

[0009] One of the technical solutions adopted to achieve the objective of this invention is: to provide a combustion-supporting ball for coal combustion, the combustion-supporting ball comprising an aluminum foil shell and a filling material wrapped inside therein, the filling material comprising a reducing agent, an oxide, an oxidizing agent, a leavening agent and a desulfurizing agent;

[0010] The combustion-supporting ball comprises, by weight percentage: 8-10% aluminum foil shell; 6-10% aluminum powder; 35-51% oxide; 13-23% oxidant; 9-19% leavening agent; and 3-13% desulfurizer.

[0011] The oxide is selected from CuO and / or Fe2O3; the diameter of the combustion-supporting ball is 0.7 to 0.8 cm.

[0012] The general concept of a combustion-supporting sphere for coal combustion provided by this invention is as follows:

[0013] This invention introduces an aluminothermic reaction system based on Al / CuO and Al / Fe2O3 into the coal combustion process to improve coal combustion efficiency. To ensure that the powder can react successfully in the blast furnace without causing safety hazards due to the vigorous aluminothermic reaction, this invention provides a novel combustion-supporting ball manufactured using an encapsulation method.

[0014] The outer shell of this combustion-supporting ball is made of aluminum foil, the main component of which is aluminum. Using aluminum foil as the outer shell to enclose the internal filling material has three advantages: First, aluminum foil has higher stability than aluminum powder. This invention uses aluminum foil to replace most of the aluminum powder, improving the safety of industrial production, processing, and use, and reducing environmental maintenance costs in the workshop. Second, the alumina on the surface of the aluminum foil can provide short-term heat insulation, delaying the powder reaction and providing a certain time buffer for the combustion-supporting ball to be evenly dispersed throughout the furnace. Simultaneously, the melted alumina itself can also act as an effective combustion aid and descaling agent. Third, the aluminum foil... Its internal filling is covered, which saves the use of other packaging materials before use and avoids the introduction of unnecessary components. During use, the combustion-supporting ball is injected into the blast furnace with the pulverized coal and dispersed in various parts of the furnace. When the temperature reaches the ignition point of the internal powder, the aluminum foil shell and the CuO or Fe2O3 inside produce an aluminothermic self-propagating reaction, which instantly generates huge local heat and combustion shock wave, causing the combustion-supporting ball to explode instantly. It generates a strong hot air flow to stir the pulverized coal, improve the combustion quality of the pulverized coal, and thus effectively play its role in assisting combustion. Fourth, the excess aluminum foil itself can also play a combustion role, further increasing the heat.

[0015] In the above technical solution, the aluminum in the aluminum foil and aluminum powder, together with oxides CuO and / or Fe2O3, constitutes an aluminothermic reaction system. With the aid of an oxidizer, the aluminothermic reaction can fully occur. After the combustion-supporting ball explodes, the expanding agent in the packing disperses to various locations, further agitating the coal powder through the explosion, resulting in a more uniform dispersion of the combustion-supporting components and improved combustion quality. In this invention, considering the explosion range and effect of the combustion-supporting ball, its diameter is set to 0.7–0.8 cm. At this size, it is slightly larger than the coal powder particle size, ensuring that a certain amount of coal powder adheres to the small ball after simple mixing, and preventing the combustion-supporting ball from agglomerating due to excessive weight or size, thus ensuring its overall combustion-supporting effect when injected into the blast furnace. Furthermore, by adjusting the proportion of aluminum foil shell, an aluminum foil shell of a certain thickness is formed, resulting in better heat insulation and a longer buffer time for the reaction, ensuring the safety of the combustion-supporting ball in use and the uniformity of its injection into the blast furnace.

[0016] In some preferred embodiments, the components in the combustion-supporting ball, by weight percentage, include: 10% aluminum foil shell; 6% aluminum powder; 16% aluminum foil shell; 44% oxide; 18% oxidant; 14% leavening agent; and 8% desulfurizer. In the above raw materials, the amount of aluminum in the aluminum foil and aluminum powder is approximately 20% excess relative to the oxide. This formulation design primarily considers the sustainability of the coal combustion process. The overall combustion-supporting stage is divided into three parts. The first part is when the temperature reaches the ignition point of the aluminothermic reaction, causing aluminothermic self-propagating reaction, which lowers the ignition point of the surrounding coal powder and promotes combustion. The second part is that, simultaneously with the reaction, the combustion-supporting ball explodes under the action of the strong thermal shock wave generated by the self-propagation. With the thrust of the internal and external pressure difference, the shock wave radiates over a wider range, fully agitating the surrounding coal powder, increasing the contact area for combustion, and playing a role in combustion support. The third part is that the expanding agent after the combustion-supporting ball explodes disperses to various parts of the furnace. It can expand instantly at high temperature, making the coal in a loose state, increasing the specific surface area, increasing the oxygen supply surface, and making combustion more complete.

[0017] Preferably, the oxide is prepared by mixing CuO and Fe2O3 in a mass ratio of 2:1. The Al / CuO type aluminothermic reaction is stable and has a large heat release, playing a major role in heat release. The Al / Fe2O3 type aluminothermic reaction has a slightly smaller heat release than the Al / CuO type aluminothermic reaction. During the reaction, some iron oxide decomposes at high temperature into iron(III) oxide and oxygen to participate in the reaction. The free oxygen will generate a huge impact force in the reaction, which can ensure that a sufficiently strong shock wave is generated after the reaction, so as to fully agitate the surrounding coal powder and improve the combustion quality.

[0018] Furthermore, the oxidant is a mixture of KMnO4 and KClO4 in a mass ratio of 3:2. In this invention, potassium permanganate and potassium perchlorate can react with the excess aluminum after the aluminothermic reaction to continue releasing heat and ensure coal combustion. Simultaneously, the manganese dioxide in the products further enhances the combustion-supporting effect. The combustion-supporting mechanism lies in the fact that the active oxygen released during thermal decomposition accelerates the flame propagation speed in the initial stage of ignition, thereby increasing the coal powder combustion rate. The remaining potassium permanganate and potassium perchlorate can gradually decompose and release active oxygen at different temperature ranges, increasing the contact area between carbon and oxygen. Under the catalytic action of the manganese dioxide and potassium chloride products, the oxidation reaction can occur completely.

[0019] Furthermore, the desulfurizing agent is CaCO3. In this invention, calcium carbonate decomposes at high temperature to produce CO2 gas, which fully agitates the coal combustion, making it more complete. Another product, CaO, can act as a channel for transporting active oxygen, promoting the combustion of pulverized coal. At the same time, it can form a complex salt with alumina and calcium sulfate, which coats the surface of calcium sulfate and inhibits its decomposition, thus playing a role in sulfur fixation.

[0020] Furthermore, the leavening agent is NaCl. In this invention, sodium chloride expands instantaneously at high temperatures, making the coal fluffy, increasing its specific surface area, expanding the oxygen supply surface, and making combustion more complete. Simultaneously, when the temperature reaches 800℃, sodium chloride decomposes into elemental sodium and chlorine, both of which have catalytic and combustion-supporting effects.

[0021] The second technical solution adopted by the present invention to achieve the objective is: to provide a method for manufacturing a combustion-supporting briquette for coal combustion based on the first objective of the present invention, comprising the following steps:

[0022] S1. Cut the aluminum foil into several regularly shaped aluminum foil sheets;

[0023] S2. After drying each component in the filler, weigh them according to the proportion, mix them thoroughly to obtain powder, and place a certain amount of the powder on each aluminum foil sheet;

[0024] S3. Fold the aluminum foil sheet so that the powder inside it is wrapped in it to form a spherical shape;

[0025] S4. Seal the edge of the spherical body with an adhesive to obtain a combustion-supporting ball for coal combustion.

[0026] Furthermore, in step S1, the aluminum foil can be circular, square, or a regular polygon. Preferably, the aluminum foil is a 10×10cm square block, and in step S2, 2.2–4.0g of the powder is placed on each aluminum foil.

[0027] Furthermore, in step S2, the drying temperature is 50–60°C, and the drying time is 4–5 hours. Thoroughly drying the raw materials before mixing helps to facilitate a better aluminothermic reaction.

[0028] Furthermore, in step S4, the adhesive is a high-temperature adhesive.

[0029] In some preferred embodiments, the preparation method specifically includes:

[0030] S1. Cut aluminum foil with a thickness of 0.02 to 0.025 mm into square pieces of 10 × 10 cm;

[0031] S2. Weigh each component in the filler according to the proportion, mix them thoroughly to obtain powder, and place 2.2 to 4.0 g of the powder on each of the square blocks;

[0032] S3. Fold the square block so that the powder inside it is enclosed to form a sphere with a diameter of 0.7 to 0.8 cm;

[0033] S4. The edges of the spherical body are sealed with high-temperature adhesive to obtain a combustion-supporting ball for coal combustion.

[0034] The technical solution adopted to achieve the third objective of the present invention is: to provide a combustion-supporting ball for coal combustion as described in the first objective of the present invention, or an application of a combustion-supporting ball for coal combustion prepared by the preparation method described in the second objective of the present invention, which includes: uniformly mixing the combustion-supporting ball with pulverized coal at a mass ratio of 1:8000, and then injecting it into a blast furnace for combustion.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] (1) The present invention provides a combustion-supporting ball for coal combustion, which incorporates the aluminothermic reaction into the design concept of coal additives. It uses aluminum foil to wrap oxides and other combustion-supporting raw materials, and replaces most of the aluminum powder with aluminum foil. This reduces the danger of industrial production and use of aluminum powder with high explosion sensitivity coefficient. It not only ensures safety in actual production, but also greatly improves the combustion efficiency of coal itself and improves the combustion quality of coal, taking into account both economy and environmental protection.

[0037] (2) The combustion-supporting balls for coal combustion prepared by this invention are granular small balls. After being mixed with coal and sprayed into the blast furnace, the aluminum foil outer shell undergoes an aluminothermic reaction with the CuO and / or Fe2O3 inside. The instantaneous high temperature causes a small-scale expansion and explosion, stirring the airflow in the coal bed and promoting the detachment of ash or combustion product CO from the surface of the carbon particles, thus ensuring complete combustion. Furthermore, the preparation process of the combustion-supporting balls prepared by this invention is simple, safe, and convenient to use. The amount added to the coal is small, the combustion-supporting effect is good, it has good adaptability to different coal types, and it is easy to promote and apply. Attached Figure Description

[0038] Figure 1 This is a schematic flowchart illustrating a method for manufacturing combustion-supporting balls for coal combustion, provided by an embodiment of the present invention. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0040] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0041] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0042] Example 1

[0043] A combustion-supporting ball for coal combustion comprises the following raw materials by mass fraction: 8% aluminum foil shell; 6% aluminum powder; 51% CuO; 23% oxidant; 9% leavening agent; and 3% desulfurizer. The oxidant consists of 60% KMnO4 and 40% KClO4, the leavening agent is NaCl, and the desulfurizer is CaCO3.

[0044] Its production method includes the following steps:

[0045] Step 1: Cut the 0.025mm aluminum foil into several 10×10cm square pieces;

[0046] Step 2: After drying all the additives at 60℃ for 4 hours, weigh them according to the proportion, mix them with a 3D powder mixer for 10 hours, and then place 4.0g of additive powder on each square piece of aluminum foil.

[0047] Step 3: Fold each sheet of aluminum foil into a closed sphere with a diameter of 0.7-0.8 cm;

[0048] Step 4: Seal the edges of the spherical body with high-temperature adhesive to obtain a combustion-supporting ball for coal combustion.

[0049] Example 2

[0050] A combustion-supporting ball for coal combustion comprises the following raw materials by mass fraction: 10% aluminum foil shell; 10% aluminum powder; 35% CuO; 19% leavening agent; and 13% desulfurizing agent. The oxidizing agent consists of 60% KMnO4 and 40% KClO4, the leavening agent is NaCl, and the desulfurizing agent is CaCO3.

[0051] Its production method includes the following steps:

[0052] Step 1: Cut the 0.02mm aluminum foil into several 10×10cm square pieces;

[0053] Step 2: After drying all the additives at 50℃ for 5 hours, weigh them according to the proportion, mix them with a 3D powder mixer for 6 hours, and then take them out and place 2.2g of additive powder on each square piece of aluminum foil.

[0054] Step 3: Fold each sheet of aluminum foil into a closed sphere with a diameter of 0.7-0.8 cm;

[0055] Step 4: Seal the edges of the spherical body with high-temperature adhesive to obtain a combustion-supporting ball for coal combustion.

[0056] Example 3

[0057] A combustion-supporting ball for coal combustion comprises the following raw materials by mass fraction: 10% aluminum foil shell; 6% aluminum powder; 44% oxide; 18% oxidant; 14% leavening agent; and 8% desulfurizer. The oxide is prepared by mixing CuO and Fe2O3 in a 2:1 mass ratio; the oxidant consists of 60% KMnO4 and 40% KClO4; the leavening agent is NaCl; and the desulfurizer is CaCO3.

[0058] Its production method includes the following steps:

[0059] Step 1: Cut the 0.025mm aluminum foil into several 10×10cm square pieces;

[0060] Step 2: After drying all the additives at 55℃ for 6 hours, weigh them according to the proportion, mix them with a 3D powder mixer for 6 hours, and then take them out. Place 3.6g of additive powder on each square piece of aluminum foil.

[0061] Step 3: Fold each sheet of aluminum foil into a closed sphere with a diameter of 0.7-0.8 cm;

[0062] Step 4: Seal the edges of the spherical body with high-temperature adhesive to obtain a combustion-supporting ball for coal combustion.

[0063] Performance testing

[0064] The coal combustion aid balls prepared in Examples 1-3 were mixed with pulverized coal at a mass ratio of 1:8000 and then injected into the blast furnace. The combustion aid effect of the balls was analyzed, statistically analyzed, and calculated. The results are shown in Table 1 below. The calorific value density is the heat released by the combustion of one kilogram of material per unit time. The reference value for the calorific value density of one kilogram of pulverized coal is 244.225 kJ / (kg·s).

[0065] Table 1

[0066]

[0067] As shown in the table above, the combustion-supporting balls prepared in Examples 1-3 can significantly increase the calorific value density of coal, lower the ignition point of coal, and improve the burnout of coal, thereby improving the combustion quality of coal in many ways, reducing the cost of coal, and taking into account both economic benefits and environmental protection. They are suitable for promotion and application.

[0068] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. A combustion-supporting sphere for coal combustion, characterized in that, The combustion-supporting ball includes an aluminum foil shell and a filling material wrapped inside it, the filling material including oxides, oxidants, leavening agents and desulfurizers; The combustion-supporting ball comprises, by weight percentage: 8-10% aluminum foil shell; 6-10% aluminum powder; 35-51% oxide; 13-23% oxidant; 9-19% leavening agent; and 3-13% desulfurizer. The oxide is selected from CuO and / or Fe2O3; The diameter of the combustion-supporting ball is 0.7 to 0.8 cm.

2. The combustion-supporting briquette for coal combustion according to claim 1, characterized in that, The combustion-supporting ball comprises, by weight percentage: 10% aluminum foil shell; 6% aluminum powder; 44% oxide; 18% oxidant; 14% leavening agent; and 8% desulfurizer.

3. The combustion-supporting briquette for coal combustion according to claim 2, characterized in that, The oxide is prepared by mixing CuO and Fe2O3 in a mass ratio of 2:

1.

4. The combustion-supporting briquette for coal combustion according to claim 1, characterized in that, The oxidant is a mixture of KMnO4 and KClO4 in a mass ratio of 3:

2.

5. The combustion-supporting briquette for coal combustion according to claim 1, characterized in that, The desulfurizing agent is CaCO3, and the leavening agent is NaCl.

6. A method for manufacturing a combustion-supporting briquette for coal combustion according to any one of claims 1-5, comprising the following steps: S1. Cut the aluminum foil into several regularly shaped aluminum foil sheets; S2. After drying each component in the filler, weigh them according to the proportion, mix them thoroughly to obtain powder, and place a certain amount of the powder on each aluminum foil sheet; S3. Fold the aluminum foil sheet so that the powder inside it is wrapped in it to form a spherical shape; S4. Seal the edge of the spherical body with an adhesive to obtain a combustion-supporting ball for coal combustion.

7. The manufacturing method according to claim 6, characterized in that, In step S1, the aluminum foil sheet is a 10×10cm square block.

8. The manufacturing method according to claim 7, characterized in that, In step S2, 2.2 to 4.0 g of the powder is placed on each aluminum foil sheet.

9. The manufacturing method according to claim 8, characterized in that, In step S4, the adhesive is a high-temperature adhesive.

10. The application of a combustion-supporting sphere for coal combustion according to any one of claims 1-5, or a combustion-supporting sphere for coal combustion prepared by the manufacturing method according to any one of claims 6-9, characterized in that, The combustion-supporting balls are uniformly mixed with pulverized coal at a mass ratio of 1:8000, and then injected into the blast furnace for combustion.

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