Method for increasing combustion efficiency of high volatile coal and high volatile coal composition

Abstract

The invention relates to a method for increasing the combustion efficiency of high-volatile coal and a high-volatile coal composition. The method comprises the following steps: mixing the high-volatile coal with graphitization-like coal, and adding a bulking agent for combustion. The high-volatile coal composition is prepared from the following components in parts by mass: 50 to 200 parts of high-volatile coal, 10 parts of graphitization-like coal and 0.0005 to 0.025 part of a swelling agent. According to the invention, the graphitization-like coal and the high-volatile coal are subjected to mixed combustion, soot of the high-volatile coal can be adsorbed by the graphitization-like coal in the combustion process, and the graphitization-like coal is ignited while further combustion of the soot is promoted, so that the problem of difficult combustion of the graphitization coal is solved, and the combustion efficiency of the high-volatile coal is also improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal, in particular to a method for increasing the combustion efficiency of high-volatile coal and a high-volatile coal composition. BACKGROUND

[0002] Peat is the initial stage of coal formation, mainly composed of plant residues transformed through biochemical action. It retains the structure of the original plants, such as roots, stems, and leaves, and has a relatively high water content. Peat is soft in texture, usually dark brown to black in color, and has a low degree of coalification and carbon content, so its calorific value is also relatively low.

[0003] Lignite (coal) is a type of coal that evolves from peat. Compared with peat, lignite has a slightly higher degree of coalification and a corresponding increase in carbon content. It is usually brown or dark brown in color, with a dull luster and a relatively tight texture. Although the water content of lignite is lower than that of peat, it is still relatively high, which is one of the reasons why it has a long flame and produces a lot of smoke when burned.

[0004] Volatile matter refers to the mass lost by coal when heated under specific conditions, released in the form of gaseous products. It is one of the composition characteristics of coal and one of the important indicators for evaluating coal quality. Peat is a poor quality coal with high volatile matter and loose texture. Lignite is also a low degree of coalification coal with high volatile matter. Peat, lignite, and other high-volatile coals have a volatile matter of up to about 40%, high moisture, low ignition point, and strong chemical reactivity, producing a large amount of black smoke during combustion, incomplete combustion, not only causing great pollution to the environment, but also wasting carbon resources.

[0005] With the development of technology, there are many lignite improvement and utilization technologies, for example: CN103305312A discloses a processing method for manufacturing briquettes by adding biomass to lignite to reduce the water content and increase the calorific value; first, the lignite is crushed and rolled to achieve a water content of 2-3% and a density of 1-2T / m 3For example, CN105240845A discloses a lignite grading comprehensive utilization method and system, which solves the problems of difficult combustion and low burnout rate in the process of lignite gangue utilization; the lignite gangue is sent into a fluidized bed combustion furnace for combustion; the generated flue gas is dedusted; the dedusted flue gas enters a boiler to produce steam, is cooled, dried, and enters a condensation system; the obtained condensed water is purified and treated as boiler feed water and sent into the boiler; the flue gas from the condensation system is desulfurized, denitrated, and dedusted to obtain flue gas containing 80%-90% carbon dioxide by volume concentration; a part of the obtained flue gas is recycled to the fluidized bed combustion furnace and mixed with oxygen, and the remaining flue gas is captured and stored to realize zero emission of carbon dioxide. In addition, CN113154372A discloses a method for safely and efficiently blending bituminous coal in a lignite boiler, which comprises the following steps: 1) measuring the total moisture Mt, internal water Mad, calorific value Qnet,ar, Hardgrove grindability index HGI, and erosion wear index Ke of lignite and bituminous coal; 2) changing the proportion of bituminous coal, performing a power plant fan mill test, and testing the coal fineness when 10-50% bituminous coal is blended and the single mill output meets the rated load of the unit; 3) testing the one-dimensional furnace burnout rate Bp of the blended coal according to the proportion and coal fineness determined in step 2); 4) calculating the reduction of the beating plate service life when grinding bituminous coal blended coal; 5) finally determining the appropriate blending proportion of bituminous coal under the conditions that the blended coal burnout rate Bp is greater than 98.3% and the reduction of the beating plate service life T is not greater than 30%; and 6) blending and burning the bituminous coal and lignite on separate belts according to the proportion of bituminous coal determined in steps 1-5) to realize pre-blending and burning in the furnace. However, the above-mentioned prior art method has high cost, complex operation, and limited improvement in the combustion efficiency of lignite.

[0006] Graphitized coal is widely available, such as residual anode carbon powder in the electrolytic aluminum industry, refined carbon separated from carbon residue, fly ash in the coal chemical industry, and the like. These coal powders have graphitized characteristics, high ignition point, and are not easy to burn, but have huge calorific value. At present, the utilization of graphitized coal is limited, and is mostly used for soil improvement and building materials, and the calorific value thereof is not effectively utilized.

[0007] Therefore, how to fully utilize graphitized coal while increasing the combustion efficiency of high-volatile coal such as peat and lignite, and improving the calorific value utilization rate of graphitized coal and high-volatile coal, has become a technical problem to be solved. Therefore, the present application is proposed. SUMMARY

[0008] In view of the above prior art, especially the problem that the calorific value of graphitizable coal and high volatile coal is not fully utilized in the prior art. The present application found that the soot of high volatile coal can be adsorbed by graphitizable coal during the combustion process when the graphitizable coal is mixed with high volatile coal, which promotes the further combustion of soot and ignites the graphitizable coal. This not only solves the problem of difficult combustion of graphitizable coal, but also improves the combustion efficiency of high volatile coal. The present application is based on the above findings.

[0009] Therefore, one object of the present application is to provide a method for increasing the combustion efficiency of high volatile coal. The method is to mix graphitizable coal with high volatile coal and add a bulking agent. The bulking agent, graphitizable coal powder and high volatile coal form an inclusion body. During the combustion process, the soot of high volatile coal can be adsorbed by the bulking agent and graphitizable coal, which promotes the further combustion of soot and ignites the graphitizable coal. This solves the problems of difficult combustion of graphitizable coal and low combustion efficiency of lignite.

[0010] A second object of the present application is to provide a high combustion efficiency high volatile coal composition and briquette. The high volatile coal is used as the main raw material, and the combustion efficiency of the briquette obtained is as high as 90% or more, i.e. 90% or more of the coal components can be fully combusted without producing black smoke.

[0011] A third object of the present application is to provide a method for preparing a high combustion efficiency high volatile coal composition and briquette.

[0012] The technical solutions for achieving the above objects of the present application can be summarized as follows:

[0013] A method for increasing the combustion efficiency of high volatile coal, which is to mix high volatile coal with graphitizable coal and add a bulking agent for combustion.

[0014] According to the present application, preferably, the high volatile coal is one or a mixture of two of lignite and peat.

[0015] According to the present application, preferably, the graphitizable coal is one or a mixture of two or more of residual anode carbon powder, carbon residue, pulverized coal and coke.

[0016] According to the present application, preferably, the bulking agent is one or a mixture of two or more of floating beads, diatomite and perlite.

[0017] According to the present application, preferably, the weight ratio of high volatile coal to graphitizable coal is 5-20:1.

[0018] According to the present application, preferably, the amount of the bulking agent is 1 / 10000-1 / 100000 of the total mass of high volatile coal and graphitizable coal.

[0019] According to the present application, preferably, the high volatile coal, graphitizable coal and bulking agent are mixed and formed into briquettes before combustion, and the briquettes are combusted; more preferably, the briquettes are in the shape of one of a sphere, a honeycomb and a square.

[0020] According to the present application, a high volatile coal composition with high combustion efficiency is also provided, which comprises the following components in the following mass fractions:

[0021] The high volatile coal is 50-200 parts, the graphitizable coal is 10 parts, and the bulking agent is 0.0005-0.025 parts.

[0022] According to the present application, preferably, the high volatile coal composition with high combustion efficiency comprises the following components in the following mass fractions:

[0023] The high volatile coal is 100-150 parts, the graphitizable coal is 10 parts, and the bulking agent is 0.005-0.02 parts.

[0024] According to the present application, a briquette of the high volatile coal composition with high combustion efficiency is also provided, which comprises the following components in the following mass fractions:

[0025] The high volatile coal is 50-200 parts, the graphitizable coal is 10 parts, the bulking agent is 0.0005-0.025 parts, and the binder is 0.005-0.25 parts.

[0026] According to the present application, preferably, the briquette of the high volatile coal composition with high combustion efficiency comprises the following components in the following mass fractions:

[0027] The high volatile coal is 100-150 parts, the graphitizable coal is 10 parts, the bulking agent is 0.005-0.02 parts, and the binder is 0.02-0.2 parts.

[0028] According to the present application, preferably, the binder is an organic binder, and more preferably, the binder is one or a mixture of two or more of starch, phenolic acid resin, epoxy resin, lignocellulose and polyvinyl alcohol.

[0029] According to the present application, preferably, the briquette is in the shape of one of a sphere, a honeycomb and a square.

[0030] According to the present application, a preparation method of the briquette of the high volatile coal composition with high combustion efficiency is also provided, which comprises the following steps:

[0031] (1) The high volatile coal and the graphitizable coal are crushed and mixed uniformly to obtain a mixed coal;

[0032] (2) The mixed coal, the bulking agent and the binder are mixed and formed under the condition of adding water, and the surface water is removed to obtain the briquette.

[0033] According to the present application, preferably, the particle size of the high volatile coal and the graphitized coal after crushing in step (1) is less than or equal to 3 mm.

[0034] According to the present application, preferably, the molding pressure in step (2) is normal pressure, and the molding temperature is normal temperature.

[0035] The present application has the following advantages:

[0036] 1. The present application mixes high volatile coal and graphitized coal, and adds a bulking agent. In the combustion process, the soot of the high volatile coal is adsorbed by the bulking agent and the graphitized coal, which promotes the further combustion of the soot and ignites the graphitized coal. This not only solves the problem of difficult combustion of the graphitized coal, but also improves the combustion efficiency of the high volatile coal.

[0037] 2. The high volatile coal composition and the briquetted coal of the present application do not produce black smoke in the combustion process, which solves the problem of environmental pollution caused by incomplete combustion of high volatile coal.

[0038] 3. The present application also solves the problem of difficult combustion of the graphitized coal, which not only makes full use of the calorific value of the graphitized coal, but also provides a good way for the resource recycling of the graphitized coal.

[0039] 4. The present application has simple and mild conditions for preparing the high volatile coal composition briquetted coal, which can be completed at normal temperature and pressure. The cold compression strength of the briquetted coal is high, the equipment is simple, the investment is small, and it is easy to industrialize.

[0040] 5. The present application has no specific requirements for the moisture content of the high volatile coal and the graphitized coal, which can solve the problem of difficult storage of high-moisture coal and lignite. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 The photo of the high combustion efficiency high volatile coal composition briquetted coal prepared in Example 9 during combustion.

[0042] Figure 2 The photo of the lignite alone during combustion in Example 9. DETAILED DESCRIPTION

[0043] The present application mixes the graphitized coal and the high volatile coal for combustion. In the combustion process, the soot of the high volatile coal is adsorbed by the graphitized coal, which promotes the further combustion of the soot and ignites the graphitized coal. This not only solves the problem of difficult combustion of the graphitized coal, but also improves the combustion efficiency of the high volatile coal.

[0044] The present application increases the combustion efficiency of the high volatile coal. The method is to mix the high volatile coal and the graphitized coal, and add a bulking agent for combustion.

[0045] According to the present application, the volatile matter of the high volatile coal is more than 20%, even up to 40-60%. Due to the high volatile matter, a large amount of black smoke is generated during combustion, the combustion is incomplete, and the combustion efficiency is low.

[0046] In one or more preferred embodiments, the high volatile coal is one of lignite or peat, or a mixture of the two. The present application does not have special requirements for the moisture content of the high volatile coal. Lignite with a moisture content of 10-60% and peat with a moisture content of 70-90% can be used in the present application.

[0047] According to the present application, the graphitized coal has graphitized characteristics, a high ignition point, and is not easy to burn, but has a huge calorific value. It is widely available, such as residual anode carbon powder in the electrolytic aluminum industry, refined carbon separated from carbon residue, and fly ash in the coal chemical industry.

[0048] In one or more preferred embodiments, the graphitized coal is one of residual anode carbon powder, carbon residue, pulverized coal, or a mixture of two or more thereof.

[0049] According to the present application, the bulking agent and the graphitized coal act simultaneously, adsorb the carbon smoke generated during the combustion of the high volatile coal, promote the further combustion of the carbon smoke, and ignite the graphitized coal.

[0050] In one or more preferred embodiments, the bulking agent is one of floating beads, diatomite, or a mixture of two or more thereof.

[0051] According to the present application, the amount of graphitized coal used should be kept within a suitable range. Due to its difficult-to-burn characteristics, excessive use will affect the combustion of the high volatile coal, and too low an amount will reduce the adsorption effect on the carbon smoke.

[0052] In one or more preferred embodiments, the weight ratio of the high volatile coal to the graphitized coal is 5-20:1, for example, 8:1, 10:1, 12:1, 15:1, or 18:1.

[0053] In one or more preferred embodiments, the amount of the bulking agent is 1 / 10000-1 / 100000 of the total mass of the high volatile coal and the graphitized coal, for example, 2 / 100000, 5 / 100000, or 8 / 100000.

[0054] In one or more preferred embodiments, the high volatile coal, the graphitized coal, and the bulking agent are mixed and formed into briquettes before combustion, and the briquettes are then combusted. Further preferably, the shape of the briquettes is one of spherical, honeycomb, or square.

[0055] According to the present application, there is also provided a high-volatile coal composition with high combustion efficiency, comprising the following components in mass parts:

[0056] high-volatile coal 50-200 parts, graphitizable coal 10 parts, bulking agent 0.0005-0.025 parts.

[0057] In one or more preferred embodiments, the high-volatile coal composition with high combustion efficiency comprises the following components in mass parts:

[0058] high-volatile coal 100-150 parts, graphitizable coal 10 parts, bulking agent 0.005-0.02 parts.

[0059] According to the present application, there is also provided a high-volatile coal composition with high combustion efficiency, comprising the following components in mass parts:

[0060] high-volatile coal 50-200 parts, graphitizable coal 10 parts, bulking agent 0.0005-0.025 parts, binder 0.005-0.25 parts.

[0061] In one or more preferred embodiments, the high-volatile coal composition with high combustion efficiency comprises the following components in mass parts:

[0062] high-volatile coal 100-150 parts, graphitizable coal 10 parts, bulking agent 0.005-0.02 parts, binder 0.02-0.2 parts.

[0063] According to the present application, the types of high-volatile coal, graphitizable coal, and bulking agent in the high-volatile coal composition and briquette with high combustion efficiency are the same as in the method for increasing the combustion efficiency of high-volatile coal.

[0064] According to the present application, the binder is used to bond the high-volatile coal, graphitizable coal, and bulking agent together, so as to facilitate briquetting. The binder is preferably a combustible substance, which is burned together with the briquette during combustion.

[0065] In one or more preferred embodiments, the binder is an organic binder, which is further preferably one or a mixture of two or more of starch, phenolic resin, epoxy resin, lignocellulose, and polyvinyl alcohol.

[0066] According to the present application, the shape of the briquette is not particularly limited, and is selected based on the principles of facilitating storage, transportation, and combustion.

[0067] In one or more preferred embodiments, the shape of the briquette is one of spherical, honeycomb, and square.

[0068] According to the present application, a preparation method of the high-volatile coal composition briquette with high combustion efficiency is also provided, comprising the following steps:

[0069] (1) uniformly mixing the high-volatile coal and the graphitized coal after crushing to obtain a mixed coal;

[0070] (2) mixing the mixed coal, the bulking agent and the binder, and molding under the condition of adding water, and removing the surface water to obtain the briquette.

[0071] In one or more preferred embodiments, the particle size of the high-volatile coal and the graphitized coal after crushing in step (1) is ≤3 mm.

[0072] In one or more preferred embodiments, the molding pressure in step (2) is normal pressure, and the molding temperature is normal temperature.

[0073] The working principle of the present application for improving the combustion efficiency of high-volatile coal such as lignite is as follows:

[0074] The volatile matter of the high-volatile coal is quickly released during the combustion process, and the soot is formed due to the lack of time for combustion, and a large amount of black smoke is emitted during the combustion process. The bulking agent and the graphitized coal powder form an inclusion body with the high-volatile coal such as lignite, and the soot is adsorbed by the bulking agent and the graphitized coal during the combustion process, which promotes the further combustion of the soot, and at the same time, the graphitized coal is ignited, thereby improving the combustion efficiency of the high-volatile coal and solving the problem of difficult combustion of the graphitized coal.

[0075] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0076] The lignite used in the embodiments has a water content of 30%-60%, the peat used has a water content of 70%-90%, the residual anode carbon powder is from a certain electrolytic aluminum plant, and the fly ash is from a certain coal chemical plant. Other raw materials are all conventional commercially available products.

[0077] Embodiment 1

[0078] The high-volatile coal composition with high combustion efficiency comprises the following components by mass:

[0079] 10 kg of lignite, 1 kg of residual anode carbon powder, and 1.1 g of perlite.

[0080] Embodiment 2

[0081] The high-volatile coal composition with high combustion efficiency comprises the following components by mass:

[0082] Lignite 15 kg, spent anode carbon powder 1 kg, perlite 1.6 g.

[0083] Example 3

[0084] A high-volatile coal composition with high combustion efficiency, comprising the following components in parts by mass:

[0085] Lignite 20 kg, spent anode carbon powder 1 kg, perlite 2.1 g.

[0086] Example 4

[0087] A high-volatile coal composition with high combustion efficiency, comprising the following components in parts by mass:

[0088] Lignite 5 kg, spent anode carbon powder 1 kg, perlite 0.6 g.

[0089] Example 5

[0090] A high-volatile coal composition with high combustion efficiency, comprising the following components in parts by mass:

[0091] Lignite 10 kg, fly ash 1 kg, diatomite 0.8 g.

[0092] Example 6

[0093] A high-volatile coal composition with high combustion efficiency, comprising the following components in parts by mass:

[0094] Lignite 15 kg, fly ash 1 kg, floating bead 1 g.

[0095] Example 7

[0096] A high-volatile coal composition with high combustion efficiency, comprising the following components in parts by mass:

[0097] Peat 20 kg, spent anode carbon powder 1 kg, perlite 1.5 g.

[0098] Example 8

[0099] A high-volatile coal composition with high combustion efficiency, comprising the following components in parts by mass:

[0100] Peat 5 kg, fly ash 1 kg, diatomite 0.3 g.

[0101] Example 9

[0102] A high-volatile coal composition with high combustion efficiency, comprising the following components in parts by mass:

[0103] Lignite 10 kg, spent anode carbon powder 1 kg, perlite 1.1 g, phenolic acid resin 11 g.

[0104] Prepared by the following method:

[0105] (1) Lignite, residual anode carbon powder are crushed to a particle size of less than 3 mm and mixed evenly to obtain mixed coal;

[0106] (2) The mixed coal, perlite, and phenolic acid resin are mixed, water is added and mixed to a slurry, and under normal temperature and pressure conditions, spherical shapes are formed, and the surface water is removed by airing, to obtain briquettes.

[0107] Example 10

[0108] High-combustion-efficiency high-volatile coal composition briquettes, comprising the following components in mass parts:

[0109] Lignite 15 kg, residual anode carbon powder 1 kg, diatomite 1.6 g, and epoxy resin 16 g.

[0110] The preparation method is the same as that of Example 9, except that:

[0111] Honeycomb shapes are formed under normal temperature and pressure conditions.

[0112] Example 11

[0113] High-combustion-efficiency high-volatile coal composition briquettes, comprising the following components in mass parts:

[0114] Peat 20 kg, fly ash 1 kg, perlite 2.1 g, and lignocellulose 21 g.

[0115] The preparation method is the same as that of Example 9, except that:

[0116] Rectangular shapes are formed under normal temperature and pressure conditions.

[0117] Example 12

[0118] High-combustion-efficiency high-volatile coal composition briquettes, comprising the following components in mass parts:

[0119] Lignite 5 kg, residual anode carbon powder 1 kg, perlite 0.6 g, and polyvinyl alcohol 6 g.

[0120] The preparation method is the same as that of Example 9, except that:

[0121] Square shapes are formed under normal temperature and pressure conditions.

[0122] Example 13

[0123] In comparison with single lignite, peat, and anthracite, the briquettes prepared in Examples 9-12 are fully combusted in a coal stove under natural conditions, and a kettle containing 40 kg of water with an initial temperature of 30℃ is heated at the same time, with 1 kg of coal. The phenomenon during combustion is observed, and the water temperature when combustion is complete is tested.

[0124] The observation phenomenon in the combustion process and the test results of water temperature when the combustion is complete are shown in Table 1.

[0125] Table 1

[0126]

[0127] From Table 1, it can be seen that the briquette of the high volatile coal composition with high combustion efficiency has a significantly improved combustion efficiency than the lignite alone, and no black smoke is produced, which is very close to the combustion effect of anthracite. The main reason is that the briquetting technology and the introduction of the graphitized coal significantly improve the combustion efficiency of the lignite and improve the heat conversion efficiency of the lignite.

Claims

1. A method for increasing the combustion efficiency of high-volatile coal, characterized in that: The method comprises mixing high-volatile coal with graphitized coal and adding a bulking agent for combustion.

2. The method for increasing the combustion efficiency of high-volatile coal according to claim 1, characterized in that: The high volatile coal is one of lignite and peat or a mixture of the two; Preferably, the graphitized coal is one or a mixture of two or more of residual anode carbon powder, carbon slag, pulverized coal, and coke; Preferably, the leavening agent is one or a mixture of two or more of floating beads, diatomaceous earth, and perlite.

3. The method for increasing the combustion efficiency of high-volatile coal according to claim 1, characterized in that: The weight ratio of high volatile coal to graphite-like coal is 5-20:

1.

4. The method for increasing the combustion efficiency of high-volatile coal according to claim 1, characterized in that: The amount of the leavening agent used accounts for 1 / 10000-1 / 100000 of the total mass of the high-volatile coal and the graphitized coal.

5. The method for increasing the combustion efficiency of high-volatile coal according to claim 1, characterized in that: Before combustion, high volatile coal, graphite-like coal and leavening agent are mixed and formed into shaped coal, which is then burned.

6. The method for increasing the combustion efficiency of high-volatile coal according to claim 5, characterized in that: The shape of the formed coal is one of spherical, honeycomb and square.

7. A high-volatile coal composition with high combustion efficiency, characterized in that: The composition includes the following components in parts by mass: 50-200 parts of high volatile coal, 10 parts of graphitized coal, 0.0005-0.025 parts of leavening agent; Preferably, the high-volatile coal is one of lignite and peat or a mixture of two of them, the graphitized coal is one of residual anode carbon powder, carbon slag, pulverized coal, coke or a mixture of two or more thereof, and the leavening agent is one of floating beads, diatomaceous earth, and perlite or a mixture of two or more thereof.

8. A high-volatile coal composition coal briquette with high combustion efficiency, characterized in that: The composition includes the following components in parts by mass: 50-200 parts of high volatile coal, 10 parts of graphitized coal, 0.0005-0.025 parts of leavening agent, 0.005-0.25 parts of binder; Preferably, the high-volatile coal is one of lignite and peat, or a mixture of two of them; the graphitized coal is one of residual anode carbon powder, carbon slag, pulverized coal, and coke, or a mixture of two or more of them; and the leavening agent is one of floating beads, diatomaceous earth, and perlite, or a mixture of two or more of them; Preferably, the adhesive is an organic adhesive, more preferably one or a mixture of two or more of starch, phenolic resin, epoxy resin, lignocellulose, and polyvinyl alcohol.

9. The method for preparing the high-volatile coal composition coal forming machine with high combustion efficiency according to claim 8, comprising the following steps: (1) crushing high volatile coal and graphitized coal and then mixing them evenly to obtain mixed coal; (2) Mix the mixed coal, leavening agent and adhesive, shape them under the condition of adding water, and remove the water on the surface to obtain shaped coal.

10. The method for preparing a high-volatile coal composition coal forming machine with high combustion efficiency according to claim 9, characterized in that: The particle size of high volatile coal and graphitized coal after crushing in step (1) is ≤3mm; Preferably, the shape of the formed coal in step (2) is one of spherical, honeycomb, and square.

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