RU2396306C1 - Method of producing fuel briquette (versions) - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to production of fuel briquettes from carbon-containing fine-fraction materials. Proposed method comprises preliminary mixing of melasses and lime-containing component to get modified binder to be mixed with fine-fraction carbon-containing mineral material and forming briquettes with the following ratio of components, % by weight: melasses 1.8-7.0, lime-containing component (in terms of Ca(OH)₂) 0.8-3.2, fine-fraction carbon-containing mineral material making the rest. Ratio between melasses and carbon-containing component (in terms of Ca(OH)₂) makes 1:(0.25-0.75), respectively. In compliance with the other version, proposed method comprises preliminary mixing of melasses and lime-containing component to get modified binder to be mixed with fine-fraction carbon-containing mineral material, fine-fraction vegetable materisl and forming briquettes with the following ratio of components, % by weight: melasses 3.0-9.0, lime-containing component (in terms of Ca(OH)₂) 1.2-4.5, fine-fraction carbon-containing vegetable material 5.0-20.0, and fine-fraction carbon-containing mineral material making the rest. Ratio between melasses and carbon-containing component (in terms of Ca(OH)₂) makes 1:(0.25-0.75), respectively.

EFFECT: improved ecological properties, simplified production process.

11 cl, 2 ex, 2 tbl

Description

The invention relates to a method for the production of briquette solid fuel based on fine-fraction carbon-containing materials used for burning in small furnaces of boiler houses of housing and communal services and industrial enterprises, railway cars, household stoves and other low-power power plants, as well as chimney fuel.

A known method of manufacturing solid fuels based on a mixture of carbon-containing materials of plant and mineral origin, including crushed plant waste and coal and / or coke breeze and binders from the group comprising lignosulfonate, mellas, tall pitch or mixtures thereof, binders from the group of synthetic wax, paraffin or paraffin wax, as well as cement or clay (RF patent No. 2147029, IPC C10L 5/44, 2000). The disadvantage of this method is the complexity of the manufacturing technology of the fuel briquette, since some components of the mixture require heating to a temperature of 45-70 ° C, which leads to increased energy consumption. The use of components such as paraffin wax, paraffin, etc., worsens the environmental performance of the finished product. The use of clay as a cement, leads to an increase in the ash content of briquette fuel. In addition, cement is a targeted, expensive product.

A known method of manufacturing solid fuels based on carbon-containing materials of mineral origin, comprising a mixture of coal fines, molasses and inorganic hardener (US patent No. 4738685, IPC C10L 5/10, 1988). According to this production method, briquettes are cured at room temperature for 1-3 days or in a furnace at a temperature of 200 to 300 ° C for 1 hour in order to increase the strength of the briquettes, since the efficiency of the curing operation during the process is low, which is directly related to the low initial strength of briquettes.

A known method of manufacturing a solid fuel based on coal fines using molasses as a binder, as well as additives for regulating the moisture content in coal fines - quicklime, when an additional drying or heating operation is not required to remove moisture from coal fines (RF patent No. 2224007 IPC C10L 5/02, 2001). Moisture is removed due to an exothermic reaction, during which quicklime, absorbing moisture contained in coal, turns into slaked lime. The achievement of increased strength occurs due to the binding ability of calcium sugar, formed as a result of a chemical reaction between quicklime and molasses. A method of manufacturing briquettes involves mixing 1-5 parts by weight of quicklime with 100 parts by weight coal fines and keeping the mixture, mixing 7-15 parts by weight molasses with a seasoned mixture and further direct molding of the mixture in order to obtain briquettes.

The disadvantage of this method is the use of lime. The use of this product complicates the technology of manufacturing a coal briquette, since it is necessary to strictly observe the water-lime ratio and exposure time so that the mass does not lose the setting and hardening properties, otherwise the strength properties of the briquettes will not be achieved and the stability of their performance will not be ensured. When working with quicklime, caustic dust appears, and therefore working conditions worsen, lime should be stored in an airtight container. The disadvantage of the method of manufacturing a coal briquette is also the duration of mixing and maintaining the mass prior to molding, as well as the high percentage of binder consumption. All this worsens the economic performance of the briquette manufacturing process and increases the cost of briquettes.

The closest is a method of manufacturing a fuel briquette, including either anthracite or coal fines, or coal sludge, or mixtures thereof, bottoms of oil refining / 0.4-0.6 wt.% /, As a binder polysaccharide molasses / 3.0- 3.6 wt.% / And additionally carbide sludge / 0.4-1.0 wt.% /. The mechanical compressive strength of the obtained fuel briquettes is 12-15 MPa (RF patent No. 2205204, IPC C10L 5/02, 2001). A method for producing briquettes involves separate mixing of carbon-containing material with carbide sludge and bottoms with molasses at 40-50 ° C, their subsequent mixing and pressing at a pressure of 30 MPa. Vat residues of oil refining, being an anionic water repellent, increase the wetting and adhesive ability of the binder. Carbide sludge as a lime-containing product increases the content of polar groups on the surface of coal, thereby contributing to the formation of spatially cross-linked valence and coordination bonds of structures with high density, strength, and weather and water resistance.

The disadvantage of this method is the use of bottoms of oil refining, for example bottoms of thermal cracking of paraffins of normal structure, which reduces the environmental friendliness of fuel briquettes, especially when burning them. Preparation of the initial components - coal waste, molasses, bottoms of oil refining, requires their heating to a temperature of 40-50 ° C, which complicates the technology of manufacturing fuel briquettes and increases the cost of their production, and ultimately leads to higher prices for finished products.

The objective of the invention is the disposal with minimal energy consumption of waste having an energy potential, the creation of environmentally friendly and high-strength freshly formed fuel briquettes that do not require heating and drying for hardening, simplification of briquetting technology.

The technical result of the invention is to increase the environmental friendliness of the fuel and simplify the process due to the absence of the need to heat the mixture while maintaining the mechanical strength and moisture resistance of the briquettes.

The technical result is achieved by a method including preliminary mixing of molasses and a lime-containing component (for example, carbide sludge), followed by mixing the obtained modified binder with finely fractional carbon-containing material of mineral origin and further molding briquettes in the following ratio of components, wt.%:

molasses 1.8-7.0 lime-containing component / in terms of Ca (OH) ₂ / 0.8-3.2 fine carbon-containing material mineral origin rest.

The ratio of molasses and lime-containing component in terms of Ca (OH) ₂ is 1: (0.25-0.75) parts, respectively.

Carbide sludge, as well as other materials containing hydrated lime, can be taken as a lime-containing component.

As fine-grained carbon-containing material of mineral origin can be taken, including either anthracite, or coal, or coke breeze, or coal sludge, or a mixture thereof.

The briquetting is preferably carried out at a pressure of at least 10 MPa.

The preferred moisture content in the material is a moisture content of not more than 12.0% by weight.

A distinctive feature of the method is a different order of mixing the components of the mixture.

The invention has an inventive step, since the effect of changing the mixing order of the components on the mechanical strength and moisture resistance of the resulting fuel briquettes is unknown.

The technical result is also achieved by the method of producing briquettes, including mixing molasses and carbide sludge, followed by mixing the obtained modified binder with finely fractional carbon-containing material of mineral origin and finely fractional material of plant origin and further molding of briquettes in the following ratio of components, wt.%:

molasses 3.0-9.0 lime-containing component / in terms of Ca (OH) ₂ / 1.2-4.5 fine carbon-containing material woody plant origin 5.0-20.0 fine carbon-containing material mineral origin rest.

The ratio of molasses and lime-containing component in terms of Ca (OH) ₂ is 1: (0.25-0.75) parts, respectively.

As a lime-containing component, carbide sludge can be taken.

As fine-grained carbon-containing material of woody plant origin, sawdust, or wood chips, or bark, or straw, or chaff, or husk of seeds, or leaves and stems of sunflower, or a mixture thereof can be used.

The briquetting is preferably carried out at a pressure of at least 10 MPa.

The preferred moisture content in the finely fractionated carbonaceous material of mineral origin is a moisture content of not more than 25.0% by weight.

A distinctive feature is a different order of mixing the components of the mixture.

The invention has an inventive step, since the effect of changing the mixing order of the components on the mechanical strength and moisture resistance of the resulting fuel briquettes is unknown.

Fuel briquette is made as follows. By preliminary mixing, a modified binder is prepared, consisting of molasses and, for example, carbide sludge in a ratio within 1: (0.25-0.75) parts of molasses and carbide sludge, respectively, in terms of Ca (OH) ₂ . The resulting binder is mixed with a coal component, such as an anthracite bar, or coke, or coal fines, or coal sludge, or a mixture thereof, and mixed until the components are evenly distributed. The briquette is pressed at a compression pressure of preferably 10-20 MPa. Pressed briquettes without heat treatment (heating and drying) are transported to storage bins in natural conditions before use.

The preferred moisture content of the coal base is a moisture content of not more than 12.0%.

To control humidity (for example, over 12.0%) of the coal component, crushed wood-plant materials, for example sawdust, or wood chips, or bark, or straw, or chaff, or husk of seeds, or leaves and stems of sunflower, or a mixture thereof, are additionally introduced . In this case, the fuel briquette is made as follows.

Preliminarily, by mixing, a modified binder is prepared, consisting of molasses and, for example, carbide sludge, preferably in a ratio within 1: (0.25-0.75) parts, respectively. The resulting binder is mixed with a coal component and with crushed carbon-containing materials of woody plant origin. The mixture is stirred until the components are evenly distributed. The briquette is pressed at a compression pressure of preferably 10-20 MPa. Pressed briquettes without heat treatment (heating and drying) are transported to storage bins in natural conditions before use.

The preferred moisture content of the coal base is a moisture content of not more than 25.0%.

The following are examples of the invention.

The following were used as the finely fractioned carbon-containing material of mineral origin:

- Anthracite bayf Zamchalovskaya PF and Gukovskaya PSC

Anthracite fines (shtib) - screenings of anthracite and waste from coal preparation plants. Anthracite is the most carbonated variety of fossil coal. The breed is grayish-black and black-gray with a bright metallic luster.

Characteristics of anthracite coal and anthracite coal from it: carbon content in organic matter - 94.9-96.2%; density - 1.4-1.8 g / cm ³ ; the yield of volatile substances is 3.5-3.7%; net calorific value - 32.4-33.0 MJ / kg; ash content - 5.0-30.0%; working humidity - 9.0-12.0%.

- Coal fines PF "Zamchalovskaya"

Coal fines - screenings of coal and waste from coal processing plants. Coal - dense rock, black or gray-black in color with a shiny, semi-matt or matte surface.

Characteristics of coal and coal fines from it: carbon content - 76-90%; density - 1.2-1.8 g / cm ³ ; the yield of volatile substances - 7-55%; net calorific value - 31.0-37.0 MJ / kg; ash content - 5.0-30.0%.

- Coke breeze TsOF "Donetsk"

Coke breeze - coke screening, particle size 0-1 mm, ash content - 10.0-45.0%; volatile yield - up to 24.0%; net calorific value - 15.2-33.5 MJ / kg; humidity up to 16.0%.

- Coal slurry PF Zamchalovskaya

Coal sludge - waste from coal preparation plants, a small class of hard coal, anthracite coal, particle size 0-1 mm, yield of volatiles - up to 8.0%; net calorific value - 15.1-31.1 MJ / kg; humidity up to 16.0%, ash content - up to 45.0%.

As a binder molasses used waste sugar factory Leningrad Krasnodar Territory.

Molasses is a waste of sugar beet production, a thick syrupy, viscous liquid from brown to dark brown. Molasses contains up to 20% water, 45-50% sugar, 20-25% organic substances and 10% non-sugar minerals.

Molasses dissolves well in any ratio in cold and hot water. The solutions are characterized by high viscosity, the density varies from 1.30 to 1.52 g / cm ³ .

As a hardener, carbide sludge was used as a waste from a factory of synthetic products in Novocherkassk, Rostov Region (STO 05807999-017-2008), containing slaked lime Ca (OH) ₂ in an amount of not less than 35%.

Carbide sludge is a lime-containing waste formed in the production of acetylene, calcium carbide. Carbide sludge is a finely dispersed gray-blue paste. Carbide sludge is not a scarce product; it accumulates in the dumps of factories and plants, and has a low cost. The content of slaked lime Ca (OH) ₂ ranges from 30-90%.

As a carbon-containing material of wood-vegetable origin, sawdust was used.

The chemical composition of most wood and plant materials is almost similar. Coal, carbon dioxide and water are the most important components of the energy balance of wood-plant materials. The carbon content in them is from 47.0 to 52.0%, the ash content is not more than 6.0%.

Example 1. Obtaining fuel briquette (composition 2, table 1)

An anthracite bar in an amount of 78.0 wt.% With a moisture content of 7.3 wt.% And coal sludge in an amount of 15.0 wt.% With a moisture content of 8.0 wt.% Are mixed together and shut with a pre-prepared modified binder. The preparation of the binder involves mixing (in a selected ratio of 0.5) molasses in an amount of 4.4 wt.% And carbide sludge in terms of Ca (OH) ₂ in an amount of 2.2 wt.%. Mixing is carried out in a propeller-type mixer. Mixing time 1-2 minutes. The resulting binder shut the carbon component and mixing the ingredients is carried out until they are evenly distributed in the mixture. The resulting mixture is molded on a roller press at a compaction pressure of 10 MPa. Pressed briquettes without additional heating and drying are sent for storage in natural conditions before use.

Other formulations shown in Table 1 are similarly prepared.

Similarly obtained compositions in which the content of the components, humidity, particle size and pressure of the press go beyond the preferred limits.

Example 2. Obtaining a fuel briquette (composition 4, table 2).

Anthracite bar with a moisture content of 12.0 wt.% In an amount of 62.25 wt.%, Coal sludge with a moisture content of 18.5 wt.% In an amount of 5.0 wt.% And sawdust with a moisture content of 3.7 wt.% In an amount of 20 , 0 wt.% Mixed with each other and shut with a pre-prepared modified binder. Particle sizes are up to 6 mm. The preparation of the binder involves mixing (in a selected ratio of 0.417) molasses in an amount of 9.0 wt.% And carbide sludge in terms of Ca (OH) ₂ in an amount of 3.75 wt.%. Mixing time 1-2 minutes. The resulting binder is shut off the coal component and the sawdust and the mixing of the ingredients is carried out until they are evenly distributed in the mixture. The resulting mixture is molded on a roller press at a compaction pressure of 20 MPa. Pressed briquettes without additional heating and drying are sent to storage in natural conditions before use.

Other formulations shown in Table 2 are similarly prepared.

Similarly obtained compositions in which the content of the components, humidity, particle size and pressure of the press go beyond the preferred limits.

The resulting briquettes are tested for quality indicators:

Mechanical compressive strength, MPa

Mechanical dropping strength,%

Ash content,%

The yield of volatiles,%

Sulfur content,%

Higher calorific value, MJ / kg (kcal / kg)

Lower calorific value, MJ / kg (kcal / kg)

The tests were conducted according to generally accepted methods (E.M. Tayu, I.A. Andreev. Methods of analysis and testing of coal. M: Nedra. 1970, 301 p .; A.T. Elishevich. Briquetting of minerals. M .: Nedra, 1989, 300 p.).

The compressive strength of briquettes is determined on cylinders with a diameter and height of 5 mm. The tests were carried out on a hydraulic press by creating a load on the sample until it is destroyed. The breaking load (press force), divided by the area of the sample, characterizes the compressive strength of the sample in MPa or in kg / cm ² .

The strength of the pillow-shaped briquettes when tested by dropping is determined as follows. At least 4 kg of whole briquettes, previously weighed, are loaded into a box with an opening bottom and placed over a metal plate at a height of 1.5 m. Then, briquettes are dropped onto the stove several times and the test pieces of briquettes are sifted on a laboratory screen or on a sieve manually until termination of the allocation of the under-sieve product. The briquettes remaining on the sieve or screen are collected in a box and weighed. The mechanical strength of the briquettes after testing by dropping them (P _m ) in percent is calculated by the formula: P _m = m / M • 100, where m is the mass of the oversize product with particle sizes of 25 mm or more after the test, kg; M - mass of briquettes subjected to drop testing, kg

Assessment of moisture resistance of briquettes is carried out as follows. Briquettes are placed on a metal mesh in a vessel at a distance of 30 mm from the water level. At the same distance, the briquettes should be on the grid from the bottom and walls of the vessel. Samples are kept in a humid environment (relative humidity above 75%) for at least 28 days. After exposure, the briquettes are subjected to a drop test. Briquettes are considered moisture resistant if the mechanical dropping strength is at least 85%.

Fuel briquettes of the compositions indicated in the tables have the following quality indicators with a moisture content of finely fractionated carbon-containing material of mineral origin up to 12% for compositions according to table 1 and up to 25% for compositions according to table 2 and particle sizes up to 6 mm:

Mechanical compressive strength, MPa - 12.0-19.3 Mechanical dropping strength,% - 85.0-100.0 Ash content,% - 8.5-25.5 The yield of volatiles,% - 6.3-8.8 Sulfur content,% - 0.8-1.0 Higher calorific value, MJ / kg (kcal / kg) - 28.60-33.44 (6825-7980) Lower calorific value, MJ / kg (kcal / kg) - 21.55-27.75 (5144-6622)

When the molasses content exceeds 7.0 wt.% (Table 1) and 9.0 (table 2), the mechanical compressive strength decreases, which is associated with a weakening of the interaction between the contacting particles due to an increase in the thickness of the binder film adsorbed on the surface of solid particles.

When the content of carbide sludge in terms of Ca (OH) _{2 in} excess of 3.2 wt.% (Table 1) and 4.5% (table 2), the mechanical compressive strength decreases, which is associated with an increase in the ductility of the mixture, leading to softening of the briquette.

When the molasses content is less than 1.8% (table 1) and 3.0% (table 2) and carbide sludge in terms of Ca (OH) ₂ less than 0.8% (table 1) and 1.2% (table 2) mechanical compressive strength decreases, which is associated with insufficient activity of the binder and hardener.

When the ratio between molasses and the active substance (hydrated lime) in the composition of carbide sludge is less than 1: 0.25 parts, the mechanical compressive strength decreases, which is associated with the failure to achieve the activation effect.

When the ratio between molasses and the active substance (hydrated lime) in the composition of carbide sludge is more than 1: 0.75 parts, the mechanical compressive strength decreases, which is associated with the rapid curing of the mixture.

When the content of wood-plant materials is higher than 20.0 wt.%, The mechanical compressive strength decreases, which is associated with a decrease in ductility, workability and formability of the mixture.

The content of fine-grained material of wood-plant origin of less than 5.0 wt.% Does not significantly affect the moisture content of carbon-containing waste, but the mechanical strength is slightly reduced.

When the moisture content of the finely fractionated carbon-containing material of mineral origin is higher than 12.0%, the mechanical compressive strength decreases, which is associated with a decrease in the adsorption properties of the binder.

When the moisture content of finely fractionated carbon-containing material of mineral origin in the presence of crushed wood-vegetable waste is above 25.0%, the mechanical compressive strength decreases, which is also associated with a decrease in the adsorption properties of the binder.

When the pressure of pressing the fuel briquette is lower than 10 MPa, the mechanical compressive strength decreases, which is associated with the failure to achieve the conditions for molecular-surface interaction between the particles of the carbon-containing material and the binder.

At a pressing pressure of more than 20 MPa, the mechanical compressive strength does not decrease, but the increase in pressure is irrational due to energy overruns and the use of more powerful press equipment.

Thus, the present invention allows to ensure the environmental safety of the fuel product by eliminating bottoms of petroleum products from the briquette, to simplify the process due to the absence of the need to heat the mixture (in accordance with the prototype, the mixture is heated at 40-50 ° C) and, accordingly, to reduce energy consumption, capital and operating costs while maintaining or increasing the mechanical compressive strength of fuel briquettes (mechanical strength is in the range 12.0-19.3 MPa). Fuel briquettes have high moisture resistance (mechanical dropping strength after moisture test is 85.6-100%). The invention allows to regulate the moisture content of the charge by introducing additional wood-and-vegetable waste.

Table 1 Composition number Anthracite block, wt.% Coke breeze, wt.% Coal slurry, wt.% Molasses, wt.% Carbide sludge (in terms of Ca (OH) ₂ ), wt.% Ratio: Ca (OH) ₂ contained in carbide sludge, per 1 part molasses Compressive strength, MPa Drop resistance,% Drop resistance (%) after moisture test one 2 3 four 5 6 7 8 9 10 one 86.85 5,0 5,0 1.8 1.35 0.750 12.37 89.6 85.7 2 78.40 - 15.0 4.4 2.20 0,500 18.60 100.0 97.7 3 70.00 - 20,0 7.0 3.00 0.429 19.30 100.0 100.0 four 92.00 5,0 - 2.2 0.80 0.364 13.77 87.3 86.6 5 79.00 10.0 5,0 4.0 2.00 0,500 16.75 98.8 94.1 6 70.10 10.0 10.0 6.7 3.20 0.478 19.10 100.0 100.0 7 71.25 20,0 - 7.0 1.75 0.250 13.70 90.2 86.8

table 2 Composition number Anthracite block, wt.% Coke breeze, wt.% Coal slurry, wt.% Sawdust, wt.% Molasses, wt.% Carbide sludge (in terms of Ca (OH) ₂ ), wt.% Ratio: Ca (OH) ₂ contained in carbide sludge, per 1 part molasses Compressive strength, MPa Drop resistance,% Drop resistance (%) after moisture test one 2 3 four 5 6 7 8 9 10 eleven one 79.90 - 10.0 5,0 3.0 2.10 0.700 12.9 85.6 85.0 2 71.95 5,0 15.0 4.6 3.45 0.750 15.7 94.4 92.3 3 76,20 5,0 - 10.0 6.0 2.80 0.467 18.2 100.0 99.3 four 62.25 5,0 - 20,0 9.0 3.75 0.417 17.5 98.8 98.0 5 87.05 - 5,0 5,0 3.75 1.20 0.320 16,4 96.5 95.1 6 70.70 - 10.0 10.0 6.5 2.80 0.431 16.8 97.0 96.7 7 61.5 15.0 - 10.0 9.0 4,50 0,500 17.0 96.3 95.4 8 74.50 - 12.0 7.0 5.2 1.30 0.250 11,2 87.7 85,2

Claims (11)

1. A method of manufacturing fuel briquettes, comprising pre-mixing molasses and a lime-containing component, followed by mixing the obtained modified binder with finely fractional carbon-containing material of mineral origin and forming briquettes, characterized by the following ratio of components, wt.%:
molasses 1.8-7.0 lime component (in terms of Ca (OH) ₂ ) 0.8-3.2 fine carbon material of mineral origin rest,
when the ratio of molasses and lime-containing component in terms of Ca (OH) ₂ 1: (0.25-0.75) parts, respectively. 2. The method according to claim 1, characterized in that carbide sludge is taken as the lime-containing component. 3. The method according to claim 1, characterized in that either anthracite, or coal, or coke breeze, or coal sludge, or a mixture thereof, is taken as a finely fractional carbon-containing material of mineral origin. 4. The method according to claim 1, characterized in that the briquetting is carried out at a pressure of at least 10 MPa. 5. The method according to claim 1, characterized in that they use finely fractional carbon-containing material of mineral origin, containing moisture not more than 12.0 wt.%. 6. A method of manufacturing fuel briquettes, comprising pre-mixing molasses and a lime-containing component, followed by mixing the obtained modified binder with finely fractional carbon-containing material of mineral origin and finely fractional material of plant origin and further molding of briquettes, characterized by the following ratio of components, wt.%:
molasses 3.0-9.0 lime component (in terms of Ca (OH) ₂ ) 1.2-4.5 fine carbon woody material 5.0-20.0 fine carbon-containing material mineral origin rest,
when the ratio of molasses and lime-containing component in terms of Ca (OH) ₂ 1: (0.25-0.75) parts, respectively. 7. The method according to claim 6, characterized in that carbide sludge is taken as the lime-containing component. 8. The method according to claim 6, characterized in that either anthracite, or coal, or coke breeze, or coal slurry, or a mixture thereof, is taken as a finely fractional carbon-containing material of mineral origin. 9. The method according to claim 6, characterized in that as a finely-fractioned carbon-containing material of woody plant origin, either sawdust, or wood chips, or bark, or straw, or chaff, or husk of seeds, or sunflower leaves and stems, or a mixture thereof . 10. The method according to claim 6, characterized in that the briquetting is carried out at a pressure of at least 10 MPa. 11. The method according to claim 6, characterized in that the finely fractional carbon-containing material of mineral origin contains moisture not more than 25.0 wt.%.