RU2367681C2 - Method of producing smoke-free lumped carbonaceous fuel - Google Patents

Abstract

FIELD: oil-and-gas production.

SUBSTANCE: method of producing smoke-free lumped carbonaceous fuel relates to processing fine grained coal industry wastes and coal dust into refined fuel for technical, household and communal purposes through laminar coking. The method of producing smoke-free lumped carbonaceous fuel involves mixing coal sludge and coal dust and thermal processing, and is distinguished by that, the coal sludge is in form of waste coal, taken in amount of 15-35 wt % and the coal dust is ground gas coal of a fraction of less than 3 mm, taken in amount of 65-85 wt %, which are then treated with an inert heat carrier to temperature of 150-250°C after mixing and then coked.

EFFECT: faster laminar coking, design of non-waste technology for coal-preparation plants, increased mechanical strength of the fuel, possibility of using the fuel in industrial high-capacity furnaces with flame combustion mode, fluidised bed furnaces and grate-fired furnaces, reduced cost of the obtained fuel.

3 cl, 1 tbl, 2 dwg

Description

The present invention relates to the coal industry, namely to processing by layer coking of coal industry waste, mainly coal enrichment waste and small coal into refined fuel, and can be used for household and technological purposes.

A known method for producing coal briquettes, including dehydration of coal sludge to 10-35% moisture content, mixing coal particles and the mineral component of the original sludge, the subsequent formation of dehydrated sludge (with a particle size distribution of 1 mm of at least 90%) and sintering coal, in an amount of not less than 25%, with a total ash content of 30-70% under a pressure of 0.001-20 MPa and subsequent heat treatment at a temperature of 200-700 ° C for 1-60 minutes in an unoxidized environment [RF Patent for the invention No. 2087527, cl. C10L 5/08, publ. 08/20/97].

The disadvantages of this method include significant cost due to the use of equipment for pressing and heat treatment at high temperature for a long time, the inability to use in industrial high-performance furnaces.

The closest in technical essence to the claimed method is a method for producing coal briquettes, comprising mixing a mixture of coal sludge and coal fines with 4-5 wt.% Dry lignosulfonate, briquetting the mixture and subsequent heat treatment of the briquettes, using the mixture at a moisture content of 8-14%, when the composition of coal sludge fraction 0.5 mm - 50-90 wt.% and coal fines fraction 6 mm - 5-46 wt.%, heat treatment of briquettes is carried out in the range of 160-200 ° C for 1.0-1.5 hours [RF patent for the invention No. 2078794, class. C10L 5/20, publ. 05/10/97].

The disadvantages of this method are the duration of the process of layer-by-layer coking, insufficient water resistance and mechanical strength of the fuel, the need to use special non-standard equipment, the inability to use in industrial high-performance furnaces with a flare mode of fuel combustion, the high cost of the resulting fuel.

The basis of the invention is the task of improving the method for producing smokeless lumpy carbon fuel, in which the use of coal enrichment waste as coal slurry in the amount of 15-35 wt.%, And as coal fines - gas coal fractions less than 3 mm, in the amount of 65-85% , after mixing - heat treatment with an inert coolant to a temperature of 150-250 ° C and layer coking provide acceleration of the process of layer coking, this ensures water resistance and increase the mechanical strength of the fuel, the possibility of creating non-waste technology in the operation of coal processing plants, the use of fuel in industrial high-performance furnaces with flare, boiling and layered combustion modes, simplifying the process, reducing the cost of fuel received.

The problem is solved in that in the method for producing smokeless lumpy carbonaceous fuel, including mixing into the mixture of coal sludge and coal fines, heat treatment, according to the invention, the following differences are provided:

- as coal sludge take coal waste in an amount of 15-35 wt.%;

- as coal fines - crushed gas coal fractions of less than 3 mm, in the amount of 65-85 wt.%;

- coal preparation waste and crushed gas coal after mixing are thermally treated with an inert coolant to a temperature of 150-250 ° C;

- the mixture, after heat treatment, is coked.

In addition, low-sulfur low-sulfur morphine is taken, and coking is carried out in coke ovens by layered coking to a temperature along the axis of the coking chamber of 750-1050 ° C.

The method is illustrated by drawings, where:

figure 1 shows a graph of the dynamics of burnout of a sample of particles of anthracite "A" (curve 1), lean coal "T" (curve 2), gas coal "G" (curve 3);

figure 3 is a graph of the dependence of the rate of interaction (RmO) of coke residues of anthracite "A", lean "T" and the proposed smokeless fuel with atmospheric oxygen on the degree of conversion.

The essence of the method is as follows.

Gas coal, mainly low-metamorphosed low-sulfur coal, is preliminarily crushed to fractions less than 3 mm and thoroughly mixed with coal treatment waste with an ash content of 30-50%, while coal processing waste in the mixture is 15-35%, and gas coal 65-85%, the percentage ratio mixtures can be adjusted depending on the requirements of the consumer and the ash content of the components. Due to the low performance of the mixture in sintering and coking properties, namely, the small thickness of the plastic layer, high ash content and high yield of volatiles, the mixture is thermally treated with an inert coolant to a temperature of 150-250 ° C with high-speed heating for 3-5 s, resulting in heating is accelerated to the transition to a plastic state in the process of layer-by-layer coking, the time spent in the plastic state and the thickness of the plastic layer increase, the heat-recovery process improves, the temperature gradient decreases atura and shrinkage in the semi-coke layer is not accompanied by a drop in thermal conductivity, an increase in the density of the heated mixture and, due to an increase in the heat content of the mixture during loading, the coking process is accelerated, as a result of which a coke with sufficient mechanical strength is obtained from a weakly coked mixture. Therefore, preliminary heat treatment of the proposed mixture will allow to obtain lump fuel in traditional coke ovens layer coking from low-sintering mixture. Coking is carried out at accelerated periods of coking for 12-14 hours, the coking process is completed when the temperature along the axis of the coking chamber reaches 750-1050 ° C.

The fuel obtained in this way, in the form of lump coke with a lump size of more than 40 mm - 60%, 25-40 mm - 22.5%, having a homogeneous structure that does not collapse (unlike briquettes) under the influence of water, can withstand significant mechanical stresses crushing, erasing, does not collapse during overloads and transportation, does not require a binder and briquetting operations.

The proposed method for producing fuel has several advantages over other types of fuel: burning fuel particles in a high temperature zone with a temperature of more than 850 ° C (according to laboratory studies in a dynamic experiment) transfers the combustion mode to a phase close to external diffusion, where the reaction properties of the fuel are leveled and are determined only by the oxidizer feed rate, while the burn-up time of fuel particles is about 400 s, which is lower than when lean coal (425 s) and anthracite (430 s) burn out, and the dynamic curve burnout does not contain a peak corresponding to the exit and burnout of volatile substances, as can be seen from graph 1, while the temperature curve corresponds to the burnout of the coke residue.

The dynamics of the burnout of a sample of particles of anthracite "A", lean coal "T", gas coal "G" and the proposed smokeless lumpy carbonaceous fuel is shown in the graph (figure 1).

Thus, the burning of pulverized particles of lumpy coal fuel in an air atmosphere during a flare mode of operation of a fire chamber according to dynamic research data has advantages over traditional energy coals of grades “T” (lean) and “A” (anthracite) in terms of completeness and burnout rate.

According to the kinetics of burnout, according to kinetic studies of the combustion process (Fig. 2), particles of the proposed fuel react with atmospheric oxygen almost instantly in an oxidation reaction, while their interaction rate is 30–40 times higher than that of anthracite: a small particle of the proposed fuel it flares up and burns out intensively, as a result of which a higher temperature is formed in the combustion zone, which intensifies the processes occurring in industrial furnaces, for example, the production of steam in furnaces that require more intense the apparent arrival of heat and liquid ash (ash melting point is 1300 ° C), therefore, the proposed fuel is preferable to T and A coals, which makes it possible to refuse these expensive and scarce grades of coal.

The dependences of the rate of interaction of the coke residue of anthracite “A”, lean “T” and the proposed smokeless fuel with atmospheric oxygen on the degree of conversion (m = 0.1 mm, d = 0.1-0.16 mm, T = 560 ° C) are shown in the graph (figure 2).

An example implementation of the method

The composition of the mixture is taken: crushed gas coal from the Zarechnaya mine (Russia) - 85% and waste from coal processing plants - 15%.

The resulting mixture is thoroughly mixed and thermally treated with an inert coolant to a temperature of 200 ° C for 4 s, after which it is loaded into coke ovens of layered coking, where the coking process takes place for accelerated periods for 12 hours, until the temperature in the furnace is reached, along the axis, 1000 ° FROM.

Indicators of technical analysis of the resulting fuel are given in the table.

Sifting by size classes of lump coal: 0-25 mm - 17.6%, more than 25 mm - 82.4%.

Industrial tests of smokeless lumpy carbonaceous fuels obtained by the proposed method were carried out in a boiler plant of OJSC “Krasnoarmeyskaya-Zapadnaya Management Company” and showed improved environmental performance compared to the prototype: the amount of nitrogen dioxide emissions into the atmosphere decreased by 2.3 times, sulfur oxide - by 2 , 1 time, carbon monoxide (carbon monoxide) - 6.7 times.

Using the proposed method for producing smokeless lumpy carbonaceous fuels will make it possible to obtain fuel with a sufficiently high calorific value and mechanical strength, high reactivity, speed and completeness of burning of fuel particles, will allow the use of coal enrichment waste and create a waste-free coal enrichment technology, as well as improve environmental performance for emissions into the atmosphere .

The ability to plan the quality indicators of the proposed fuel depending on the requirements of the consumer, price competitiveness in comparison with lean coals and anthracite, and the utilization of coal preparation waste ensure the economic feasibility of using the proposed fuel.

Claims (3)

1. A method of producing smokeless lumpy carbon fuel, comprising mixing a mixture of coal sludge and fine coal, heat treatment, characterized in that the coal sludge is taken from coal enrichment in an amount of 15-35 wt.%, And as fine coal is crushed gas coal fractions less than 3 mm in an amount of 65-85 wt.%, which after mixing is treated with a thermally inert coolant to a temperature of 150-250 ° C, and then coked. 2. The method according to claim 1, characterized in that low-sulfur low-sulfur gas coal is taken as gas coal. 3. The method according to claim 1, characterized in that coking is carried out in coke ovens by layered coking to a temperature along the axis of the coking chamber of 750-1050 ° C.

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