Coal combustion additive by means of aluminum sulfate reaction and its preparation method and application

Abstract

The present application provides a kind of coal additive by means of aluminum sulfate reaction, the raw material of the coal additive includes by weight percentage: catalyst 40-55%; oxidant 25-35%; fluorite 10-20%; silicon calcium powder 2-6%; the catalyst is composed of aluminum powder and sulfate according to (3-4):1 mole ratio.The present application also provides a kind of preparation method of coal additive by means of aluminum sulfate reaction, after drying, each raw material powder is mixed, then mixed with organic cellulose and water configuration organic binder, to make several small pellets, drying is obtained coal additive.The present application also provides the application of the above-mentioned coal additive by means of aluminum sulfate reaction in improving the combustion efficiency of coal, the coal additive can greatly improve the combustion efficiency of coal by means of the high heat release system of "aluminum + sulfate", and the production cost is low, safe and environmentally friendly, has broad popularization and application prospect.

Description

Technical Field

[0001] This invention belongs to the field of coal combustion additive technology, specifically relating to a coal combustion additive that utilizes an aluminum sulfate reaction and its preparation method, as well as the application of the above-mentioned coal combustion additive in improving coal combustion efficiency. Background Technology

[0002] Global coal resources are finite and reserves are dwindling, while societal demand for coal is increasing, driving up prices. This necessitates both coal conservation and measures to improve coal utilization efficiency. Therefore, improving coal combustion efficiency to enhance equipment thermal efficiency and achieve energy conservation has attracted considerable attention, with coal combustion aids being a hot research topic. Adding small amounts of combustion aids to coal promotes complete combustion, reducing heat loss from incomplete combustion and smoke emissions. From both energy conservation and environmental protection perspectives, this has significant practical implications.

[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] Based on practical applications of domestic and international patent and literature searches, existing coal additives can be summarized into three categories according to their published principles and formulations: combustion aids, biomass fuels, and sulfur fixation. Patent CN 114410362A uses bamboo powder as a biomass fuel added to coal, which not only improves the combustion quality of coal but also solves operational problems such as high-temperature corrosion, slagging, and sintering caused by biomass fuel combustion. However, the problem that biomass fuel cannot suppress boiler fires during prolonged temporary shutdowns due to its significantly lower ignition temperature compared to coal still exists. Patent CN 103160356A focuses on the reduction of NO after coal combustion. X with SO XThe treatment ultimately achieved good results, but the preparation process was complex and the production cost was high; Patent CN 104087692 simply uses aluminum powder for combustion, which is economical, efficient and practical, but aluminum powder is a flammable and explosive powder with an extremely high explosion sensitivity coefficient, and large amounts of aluminum powder in industrial production can easily cause safety accidents.

[0005] Therefore, developing a novel coal additive with high calorific value and its preparation method to improve the combustion efficiency of coal itself, while ensuring safety in actual production and taking into account economic benefits and environmental protection, is an urgent technical problem to be solved. Summary of the Invention

[0006] One of the objectives of this invention is to provide a coal additive that can significantly improve the combustion efficiency of coal and is safe and environmentally friendly.

[0007] The second objective of this invention is to provide a method for preparing a safe and environmentally friendly coal additive that can significantly improve the combustion efficiency of coal.

[0008] The third objective of this invention is to provide an application of a coal additive that utilizes an aluminum sulfate reaction to improve coal combustion efficiency.

[0009] One of the technical solutions adopted by this invention to achieve its objective is: to provide a coal additive that utilizes an aluminum sulfate reaction, wherein the raw materials of the coal additive, by weight percentage, include:

[0010] Catalyst 40%-55%; Oxidant 25%-35%; Fluorite 10%-20%; Calcium silicate powder 2%-6%;

[0011] The catalyst is composed of aluminum powder and sulfate in a molar ratio of (3-4):1.

[0012] The coal combustion additive provided by this invention consists of a catalyst, an oxidant, fluorite, and calcium silicate powder. The catalyst is composed of aluminum powder and sulfate in a molar ratio of (3-4):1. According to the main reaction equation between aluminum powder and sulfate (8Al + 3MSO4 = 3MS + 4Al2O3; where M is one or more combinations of Ca, Mg, Ba, and Na), the aluminum powder is in significant excess relative to the sulfate in this catalyst. This excess aluminum powder in the catalyst can, on the one hand, continue to react with the oxidant to generate heat; on the other hand, during industrial coal combustion, desulfurization typically produces the byproduct CaSO4, and subsequent treatment of this byproduct increases costs. This invention utilizes the excess aluminum in the catalyst to react with the byproduct CaSO4, thereby further reducing treatment costs.

[0013] Furthermore, aluminum sulfate, as a self-propagating reaction system with extremely high exothermic properties, can undergo a violent redox reaction under certain conditions, releasing a large amount of heat instantaneously. The coal additive provided by this invention, through the reaction between aluminum and sulfate, offers the following advantages:

[0014] Firstly, the reaction between the two can provide a large amount of heat (according to reliable data, the minimum heat release of 1 mol aluminum / sulfate is 3827 kJ, which is equivalent to the heat released by the complete combustion of 130g of standard coal).

[0015] Secondly, the reaction between the two is an explosive self-propagating reaction with instantaneous high temperature. While providing a large amount of heat, it can also fully agitate the coal, increase the contact area between the coal and oxygen and other additives, increase the gas flow, and make the coal burn more completely.

[0016] Third, the products of the aluminum sulfate reaction are aluminum oxide and sulfides. Alumina itself has the function of fixing sulfur. As a metal oxide, it can also promote coal combustion. The sulfides generated by the reaction will not decompose at high temperature to produce SO2 after being treated with calcium silicate powder and fluorite. Instead, they form a low-melting-point, highly fluid eutectic that can be effectively desorbed from the coal additive, so that the catalyst reaction can proceed fully and continuously and increase the heat transfer efficiency.

[0017] Furthermore, the calcium silicate powder in the raw materials of this invention can react with iron oxide in the blast furnace to release heat and combustion heat. The generated SiO2 and CaO can continue to act as oxygen carriers to promote the continuous combustion of coal, and CaO can also play a role in sulfur fixation. The calcium fluoride contained in fluorite can improve the morphology of coal slag in the blast furnace and generate an explosion in a small area, making the slag after the reaction of coal slag with aluminum / sulfate loose and porous, improving the airflow direction in the blast furnace, and making the coal combustion more complete.

[0018] Furthermore, the sulfate is selected from one or more combinations of calcium sulfate, magnesium sulfate, barium sulfate, and sodium sulfate.

[0019] Furthermore, the oxidant is composed of potassium permanganate and potassium perchlorate in a mass ratio of (1-2):1. In this invention, aluminum powder is in excess in the catalyst. Potassium permanganate and potassium perchlorate can react with the excess aluminum after the aluminothermic reaction to continue releasing heat and promote coal combustion. Simultaneously, during the thermal decomposition of potassium permanganate and potassium perchlorate, the released active oxygen can accelerate the flame propagation speed in the initial stage of ignition, and the generated manganese dioxide can further improve the combustion rate of pulverized coal. In addition, 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 generated manganese dioxide and potassium chloride, the oxidation reaction can occur completely.

[0020] Preferably, the fluorite has a purity greater than 97 wt% and a particle size of 150-300 mesh.

[0021] Preferably, the silicon-calcium powder contains 55wt%-65wt% silicon and more than 28wt% calcium; the particle size of the silicon-calcium powder is 150-300 mesh.

[0022] The second technical solution adopted by the present invention to achieve the objective is: to provide a method for preparing a coal-fired additive according to one objective of the present invention, comprising the following steps:

[0023] The raw materials are dried and then mixed to obtain additive powder. An organic binder is added to the additive powder, mixed evenly, formed into several small pellets, and dried to obtain a coal additive.

[0024] Preferably, the drying temperature is 60-100℃ and the drying time is 3-6 hours; the powder mixing process is carried out using a 3D powder mixer and the mixing time is 6-10 hours.

[0025] Furthermore, the organic binder is prepared by mixing organic cellulose and water at a mass ratio of 1:(30-50); the amount of the organic binder is 0.5%-2% of the total weight of the additive powder. The organic cellulose binder used in this invention is derived from biomass-containing raw materials such as waste paper, sawdust, and straw, resulting in low preparation costs. Simultaneously, the organic cellulose can be burned using a catalyst or the heat generated by coal, thereby further generating heat. In addition, the molecular formula of the organic cellulose is (C6H... 10 O5)2, the combustion process is pollution-free and leaves no residue, making it more environmentally friendly.

[0026] Preferably, the drying temperature is 80-105℃. The drying process can effectively solidify the binder and remove moisture from the coal additive, allowing the coal additive to maintain its spherical shape and a certain degree of hardness, thus ensuring uniform reaction during use.

[0027] Preferably, the diameter of the small pellets is 0.9-1 cm.

[0028] The third objective of this invention is to provide an application of the coal additive prepared by the method described in the first objective of this invention or the preparation method described in the second objective of this invention, comprising: mixing the coal additive with pulverized coal at a mass ratio of (1-3):1000, and then injecting it into a blast furnace for combustion.

[0029] The coal additive prepared by this invention is safe and easy to use. Furthermore, the amount of the coal additive added to pulverized coal is small, resulting in good combustion-promoting effects; it has good adaptability to different coal types and is easy to promote and apply.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] (1) The coal additive provided by the present invention utilizes the aluminum sulfate reaction to incorporate aluminum sulfate into the design concept of coal additives. The catalytic system formed by aluminum + sulfate not only provides a large amount of heat, but also fully agitates the coal through the explosive self-propagating reaction between the two, increases the contact area between the coal and oxygen and other additives, increases the gas flow, and makes the coal burn more completely. At the same time, the product of the aluminum sulfate reaction is aluminum oxide, which can promote coal combustion as a metal oxide. The product sulfide is treated with calcium silicate powder and fluorite to form a low melting point eutectic, which can be effectively desorbed from the coal additive, so that the catalyst reaction can be fully and continuously carried out and the heat transfer efficiency can be increased.

[0032] (2) The coal additive provided by this invention utilizes an aluminum sulfate reaction and employs an excess of aluminum powder in combination with sulfate as a catalyst. The excess aluminum powder in the catalyst can, on the one hand, continue to react with the oxidant to generate heat; on the other hand, during industrial coal combustion, desulfurization usually produces the byproduct CaSO4, and subsequent treatment of this byproduct increases costs. This invention utilizes the excess aluminum in the catalyst to react with the industrial coal combustion byproduct CaSO4, which can further reduce treatment costs.

[0033] (3) The coal additive provided by the present invention, which utilizes the reaction of aluminum sulfate, adopts a self-made addition method, which is simple in process, ensures safety in actual production, greatly improves the combustion efficiency of coal itself, and takes into account both economy and environmental protection.

[0034] (4) The coal additive prepared by the present invention is used to improve the combustion efficiency of coal. It has a small addition amount in pulverized coal and a good combustion-supporting effect. It has good adaptability to different coal types and has broad prospects for promotion and application. Attached Figure Description

[0035] Figure 1 This is a schematic flowchart illustrating a method for preparing a coal additive using an aluminum sulfate reaction, as provided in an embodiment of the present invention. Detailed Implementation

[0036] 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.

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0038] like Figure 1 As shown, this embodiment of the invention provides a method for preparing a coal additive using an aluminum sulfate reaction, comprising the following steps:

[0039] Step 1: Prepare the raw materials according to the following weight proportions: 40-55 parts catalyst (composed of aluminum powder and sulfate in a molar ratio of 3-4:1), 25-35 parts oxidant (composed of potassium permanganate and potassium perchlorate in a mass ratio of 1-2:1), 10-20 parts fluorite, and 2-6 parts calcium silicate powder; dry the above raw materials at 60-100℃ for 3-6 hours.

[0040] Step 2: Mix the dried raw materials using a 3D mixer for 6-10 hours to obtain additive powder;

[0041] Step 3: Add 0.5%-2% of organic binder to the additive powder, mix evenly, and obtain a binder; wherein the organic binder is prepared by organic cellulose and water in a mass ratio of 1:(30-50);

[0042] Step 4: Form the binder into small balls with a diameter of 0.9-1cm and dry them at 80-105℃ to obtain the coal additive.

[0043] 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.

[0044] The main raw materials and their weight proportions involved in Examples 1-5 of this invention are shown in Table 1 below.

[0045] Table 1

[0046]

[0047] Example 1

[0048] This embodiment provides a coal additive prepared by reacting aluminum sulfate, and its preparation method includes the following steps:

[0049] Step 1: Prepare the following raw materials according to the weight proportions shown in Table 1: 25 parts aluminum powder, 30 parts magnesium sulfate (molar ratio of aluminum powder to sulfate is 3.7:1), 15 parts potassium permanganate, 10 parts potassium perchlorate, 18 parts fluorite, and 2 parts calcium silicate powder; dry the above raw materials at 80℃ for 5 hours.

[0050] Step 2: Mix the dried raw materials using a 3D mixer for 8 hours to obtain additive powder;

[0051] Step 3: Add an organic binder (made of organic cellulose and water in a mass ratio of 1:40) to the additive powder at a dosage of 1.5% of the total weight of the additive powder to obtain the binder.

[0052] Step 4: The binder is made into small balls with a diameter of 1 cm and dried at 85°C to obtain the coal additive.

[0053] Example 2

[0054] This embodiment provides a coal additive prepared by reacting aluminum sulfate, and its preparation method includes the following steps:

[0055] Step 1: Prepare the following raw materials according to the weight proportions shown in Table 1: 13 parts aluminum powder, 36 parts barium sulfate (molar ratio of aluminum powder to sulfate is 3.12:1), 17.5 parts potassium permanganate, 17.5 parts potassium perchlorate, 10 parts fluorite, and 6 parts calcium silicate powder; dry the above raw materials at 90℃ for 3 hours.

[0056] Step 2: Mix the dried raw materials using a 3D mixer for 6 hours to obtain additive powder;

[0057] Step 3: Add an organic binder (made of organic cellulose and water in a mass ratio of 1:50) at a dosage of 2% of the total weight of the additive powder to the additive powder to obtain the binder;

[0058] Step 4: The binder is made into small balls with a diameter of 1 cm and dried at 80°C to obtain the coal additive.

[0059] Example 3

[0060] This embodiment provides a coal additive prepared by reacting aluminum sulfate, and its preparation method includes the following steps:

[0061] Step 1: Prepare the following raw materials according to the weight proportions shown in Table 1: 20 parts aluminum powder, 30 parts sodium sulfate (molar ratio of aluminum powder to sulfate is 3.51:1), 15 parts potassium permanganate, 15 parts potassium perchlorate, 16 parts fluorite, and 4 parts calcium silicate powder; dry the above raw materials at 70°C for 6 hours.

[0062] Step 2: Mix the dried raw materials using a 3D mixer for 7 hours to obtain additive powder;

[0063] Step 3: Add an organic binder (made of organic cellulose and water in a mass ratio of 1:30) to the additive powder at a dosage of 1% of the total weight of the additive powder to obtain the binder.

[0064] Step 4: The binder is made into small balls with a diameter of 0.9 cm and dried at 90°C to obtain the coal additive.

[0065] Example 4

[0066] This embodiment provides a coal additive prepared by reacting aluminum sulfate, and its preparation method includes the following steps:

[0067] Step 1: Prepare the following raw materials according to the weight proportions in the formula shown in Table 1: 22 parts aluminum powder, 28 parts calcium sulfate (molar ratio of aluminum powder to sulfate is 3.96:1), 20 parts potassium permanganate, 10 parts potassium perchlorate, 15 parts fluorite, and 5 parts calcium silicate powder; dry the above raw materials at 75°C for 4 hours.

[0068] Step 2: Mix the dried raw materials using a 3D mixer for 6 hours to obtain additive powder;

[0069] Step 3: Add an organic binder (made of organic cellulose and water in a mass ratio of 1:40) to the additive powder at a dosage of 1.5% of the total weight of the additive powder to obtain the binder.

[0070] Step 4: The binder is made into small balls with a diameter of 0.95 cm and dried at 85°C to obtain the coal additive.

[0071] Example 5

[0072] This embodiment provides a coal additive prepared by reacting aluminum sulfate, and its preparation method includes the following steps:

[0073] Step 1: Prepare the following raw materials according to the weight proportions in the formula shown in Table 1: 12 parts aluminum powder, 28 parts barium sulfate (molar ratio of aluminum powder to sulfate is 3.70:1), 20 parts potassium permanganate, 15 parts potassium perchlorate, 20 parts fluorite, and 5 parts calcium silicate powder; dry the above raw materials at 70°C for 6 hours.

[0074] Step 2: Mix the dried raw materials using a 3D powder mixer for 5 hours to obtain additive powder;

[0075] Step 3: Add an organic binder (made of organic cellulose and water in a mass ratio of 1:30) to the additive powder at a dosage of 1% of the total weight of the additive powder to obtain the binder.

[0076] Step 4: The binder is made into small balls with a diameter of 1 cm and dried at 95°C to obtain the coal additive.

[0077] Application performance testing

[0078] The coal additives prepared in Examples 1-5 were mixed with pulverized coal at a mass ratio of 1:1000 and then injected into the blast furnace. The combustion-aiding effect of the coal additives was analyzed, statistically analyzed, and calculated. The results are shown in Table 2 below. The heat released by burning 1 kg of standard coal is 29307.6 kJ.

[0079] Table 2

[0080]

[0081] As shown in the table above, the combustion-supporting balls prepared in Examples 1-5 can significantly increase the calorific value 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.

[0082] 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 coal additive that utilizes an aluminum sulfate reaction, characterized in that, The raw materials of the coal additive, by weight percentage, include: 40%-55% catalyst; 25%-35% oxidant; 10%-20% fluorite; 2%-6% calcium silicate powder; the catalyst is composed of aluminum powder and sulfate in a molar ratio of (3-4):1; The coal additive is prepared by a method comprising the following steps: drying the raw material and then mixing it to obtain additive powder; adding an organic binder, which is prepared by organic cellulose and water in a mass ratio of 1:(30-50), to the additive powder, wherein the amount of organic binder is 0.5%-2% of the total weight of the additive powder; mixing evenly, forming several small pellets, and drying to obtain the coal additive.

2. The coal additive according to claim 1, characterized in that, The sulfate is selected from one or more combinations of calcium sulfate, magnesium sulfate, barium sulfate, and sodium sulfate.

3. The coal additive according to claim 1, characterized in that, The oxidant is composed of potassium permanganate and potassium perchlorate in a mass ratio of (1-2):

1.

4. The coal additive according to claim 1, characterized in that, The fluorite has a purity greater than 97 wt% and a particle size of 150-300 mesh.

5. The coal additive according to claim 1, characterized in that, The silicon-calcium powder contains 55wt%-65wt% silicon and more than 28wt% calcium; the particle size of the silicon-calcium powder is 150-300 mesh.

6. The coal additive according to claim 5, characterized in that, The drying process is carried out at a temperature of 60-100℃ for 3-6 hours; the powder mixing process is carried out using a 3D powder mixer for 6-10 hours.

7. The coal additive according to claim 1, characterized in that, The diameter of the small pellets is 0.9-1 cm.

8. An application of a coal additive according to any one of claims 1-7, characterized in that, The coal additive and pulverized coal are mixed evenly at a mass ratio of (1-3):1000, and then injected into the blast furnace for combustion.

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