RU2425074C2 - Binding composition for making fuel briquettes - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to coal industry, particularly producing binder for briquetting brown coal. The tar-based composition used to briquette fine fractions of brown coal is characterised by that it contains mechanically activated sapropel.

EFFECT: obtaining briquettes with good technical characteristics.

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Description

The invention relates to the coal industry and can be used for briquetting finely divided brown coal fractions using tar modified with activated lake sapropel as a binder.

A known method of producing fuel briquettes, including the preparation of a mixture of crushed coal with petroleum asphaltite (8-10 wt.%), Machining in a rotary disintegrator at a speed of rotation of the working bodies (16-18) · 10 ^-3 min ^-1 for 3-6 seconds and subsequent briquetting of the mixture when heated (RF Patent No. 2064006 “Method for producing fuel briquettes.” Auth. V.V. Pushkanov, G.S. Golovin, E.G. Gorlov, Ya.M. Kagan, A.R. Molyavko , A.A. Chizhevsky) [1].

The disadvantage of this method is the complexity of the technology for preparing the feedstock - coal dehydration according to the Fleisner method, the use of high temperatures during pressing, low compressive strength of the resulting briquettes.

Closest to the proposed technological essence is a method of briquetting coal, including grinding coal, mixing with a binder, which is used as a modified tar dried lake sapropel, pressing and heat treatment (RF Patent No. 2232159 “Saproles containing binder for brown coal briquetting.” Aut. L . A. Petrova, O. N. Burenina, V. G. Latyshev, S. N. Popov, L. Ya. Morova) [2].

The disadvantage of this method is the low strength of the resulting briquettes.

The aim of the invention is to obtain fuel briquettes with increased values of compressive strength.

This goal is achieved in that it is proposed to use a tar modified with the addition of mechanically activated lake sapropel as a binder.

Tar is a heavy oil residue after distillation of gasoline-diesel-oil distillates, which is a black resinous mass. The main components of the tar are oils that were not distilled during the distillation of oil, oil resins, solid asphalt-like substances (asphaltenes, carbenes, carboids), resinous substances of an acid nature.

Tar obtained by distillation of 40% oils from fuel oil at T = 350-370 ° C, pressure P = 0.6-0.8 atm, for 4-5 hours and has the following properties and composition (Table 1).

Table 1 Physico-chemical properties of tar Options Value Density at 20 ° С, kg / m 941.1 Conventional viscosity at 80 ° С, conv. degree 23.3 Mass fraction of silica gel resins,% 18,4 Mass fraction of asphaltenes,% 6.2 Oils,% 75.44 Mass fraction of paraffin,% 0.88 Coking ability, wt.% 10.82 Flash point in open crucible, ° С 227.5 Pour point, ° C 2 Ash content,% 0.15 Elemental composition, mass fraction - FROM 85.0 - N 13.6 - N 0.5 - S _total 0.74 - ABOUT 0.16

Excessive residual oil content in the tar (up to 75.44%) adversely affects its adhesive properties and reduces the compressive strength of fuel briquettes.

In order to accelerate the oxidation processes and improve the adhesion ability of the coal-binder system, the introduction of activated lake sapropel into the tar is proposed as a structurally active additive.

Sapropels are bottom sediments of lakes, complex organomineral complexes of substances formed as a result of biological, microbiological and mechanical processes from the remains of plant and animal organisms and organic and mineral impurities introduced into water bodies [3]. A prerequisite for using dispersed organomineral material as a modifying additive when filling a binder, in addition to its extensive raw material base and cheapness, was its unique properties caused by its increased geometric specific surface, high sorption ability of tar oils and catalytic ability [4, 5].

Before mixing with the oil binder, sapropel was dried at 110 ° C to remove part of the residual water and subjected to mechanical activation at the AGO-2 planetary mill with a carrier speed of 630 rpm and a drum of 1290 rpm for two minutes to disperse and increase the adsorption capacity .

A study of the texture characteristics of sapropels shows that activated sapropel is characterized by a smaller particle size, increased specific geometric surface, and also an increased number of pores, as can be judged by the increase in specific pore volume compared to non-activated sapropel (Table 2).

table 2 Textural characteristics of sapropels Indicators Inactive sapropel Activated sapropel The specific pore volume, cm ³ / g 0.002 0.012 Specific geometric surface, m ² / g 1,257 7,256

Studies of the dispersion of fillers show that if the size of individual sapropel particles before activation is> 180 μm, then after processing in a planetary mill it decreases by two orders of magnitude.

Thus, studies have shown that mechanical activation leads to increased adsorption properties and an increase in the dispersion of sapropels.

The composition for the briquetted fuel is prepared as follows.

Dried at 110 ° C and fractionated coal fines (particle size 0-2.5 mm) and modified with mechanically activated sapropel tar mixed in the claimed relationship at a temperature of 90 ° C. Then the resulting mixture is pressed at a pressure of 150 MPa, the finished briquette is subjected to heat treatment at 230 ° C for 180 minutes. The test samples — tablets with a diameter of 25.0 mm and a height of 10.0 mm — were tested for compressive strength, ash, volatiles yield, total sulfur content for dry fuel, total hydrogen content for air-dry fuel, water absorption, higher calorific value dry ashless state of fuel, lower heat of combustion on the working state of fuel.

Table 3 presents the technical characteristics of brown coal briquettes of known compositions No. 1, 2 [6], the proposed composition No. 4 and prototype No. 3.

As follows from a comparative analysis of the technical characteristics of the briquetted fuel, the compressive strength of the briquettes of the proposed composition is more than two times higher, the ash content and sulfur content are 1.3 times lower compared to briquettes of known compositions and prototype.

The remaining indicators are at the level of the known compositions and prototype.

Table 3 No. Structure σ _squ , MPa A ^d ,% V ^daf ,% S ^d _t ,% H ^a ,% Smoke% W% W ^a ,% Q ^daf _s , kcal / kg Q ^r _i , kcal / kg one Coal + Bitumen 11.83 15.60 46.60 0.39 3.91 113 1.86 5.20 6964 5339 2 Coal + Tar 6.12 16.00 45.80 0.33 3.81 108 2.10 5.67 6673 4761 3 Coal + tar + sapropel (prototype) 12,13 18.40 49.00 0.53 3.56 110 2.15 5.93 6840 5030 four Coal + Tar + Activated Sapropel 25.12 14.2 48 0.42 3,59 125 1.96 4.8 6824 5033 σ _{compression channel} - the compressive strength, MPa; A ^d - ash content on a dry fuel condition,%; V ^daf — yield of volatiles,%; S ^d _t - total sulfur content in the dry state of the fuel,%; N ^a - the total hydrogen content in the air-dry state of the fuel,%; W - water absorption,%; W ^a - mass fraction of moisture in the air-dry state of the fuel,%; Q ^daf _s - the highest calorific value for the dry ashless state of fuel, kcal / kg; Q ^r _i is the net calorific value per fuel operating condition, kcal / kg.

Information sources

1. RF patent No. 2064006 "Method for producing fuel briquettes." Auth. V.V. Pushkanov, G.S. Golovin, E.G. Gorlov, Y.M. Kagan, A.R. Molyavko, A.A. Chizhevsky.

2. RF patent №2326159 "Sapropel-containing binder for brown coal briquetting". Auth. L.A. Petrova, O.N.Burenina, V.G. Latyshev, S.N. Popov, L.Ya. Morova (prototype).

3. Kireicheva L.V., Khokhlova O. B. Sapropels: composition, properties, application. - M.: Roma, 1998 .-- 124 p.

4. Myarikyanov M.I., Stepanov G.N., Egorova M.S. Sapropeli of Lakes Bolshaya Chabyda, Kradenoe and ways of their use in agriculture. - Yakutsk: NSC SB RAS, 1991. - 88 p.

5. Guidelines for the use of sapropels of lakes in Central Yakutia in agriculture. - Yakutsk: NF SB RAS, 1985, - 24 p.

6. Nikolaeva L.A., Burenina O.N., Latyshev V.G. Rational use of coal waste Kangalassky coal mine PC (I). - Bulletin of the International Academy of Ecology and Life Safety, T.13, No. 3, St. Petersburg - Chita, 2008. P.14-16.

Claims (1)

Tar composition used for briquetting small brown coal fractions, characterized in that it contains mechanically activated sapropel.