RU1774131C - Method of preparation and combustion of solid fuel - Google Patents

Abstract

Use: for preparing and burning fuel. SUMMARY OF THE INVENTION: The exhaust air flows into the furnace at an angle to one another, while high-calorific fuel is supplied to the lower stream with an excess of air less than one, and in the upper one with an excess of air more than one. 1 ill. -yo yo

Description

The invention relates to the burning of solid fuels and can be used in thermal power plants.

Known methods for the preparation and burning of solid fuels are those that reduce the emissions of nitrogen oxides by inhibiting the reaction of their formation or by partially reducing the nitrogen oxide N0 formed during fuel combustion into molecular nitrogen. These include methods for preparing and burning solid fuel with flue gas recirculation; with injection of moisture into the core of burning; with the artificial creation in some burners of a deficiency, and in others of an excess of air; the use of special burners to reduce the emission of nitrogen oxides; two-stage combustion; incineration with simultaneous reduction of N0 in a flush (three-stage combustion method), etc.

P.

A known method for the preparation and combustion of solid fuels, adopted for the prototype 2.

The aim of the invention is to reduce emissions of nitrogen oxides by their reduction by products of incomplete combustion.

The proposed method of preparing and burning solid fuel by drying, grinding, separating the resulting aerosol mixture into dust and exhaust air, followed by separation of the exhaust air into two streams and supplying dust and both flows of exhaust air for combustion in the furnace, and the exhaust air flows into the furnace for different levels above the place of supply of dust to the furnace, and additional high-calorific fuel is introduced into them, characterized in that the exhaust air flows into the furnace at an angle to each other

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to a friend, moreover, high-calorific fuel is supplied to the lower stream with an excess of air less than one, and to the upper stream with an excess of air more than one.

The drawing shows a boiler plant in which the proposed method for preparing and burning solid fuel is carried out.

The boiler installation includes a hopper 1 with a feeder 2, a mill 3, a cyclone 4 with a finished dust hopper 5, equipped with a metering feeder 6, and a pipe 7 for removing dusty exhaust air to the furnace of a boiler 8 having an air heater 9, the furnace 10 is equipped with burners 11 that are connected dust pipe 12 to the hopper 6 feeder 5. The waste burner 13, into which the exhaust air is supplied via the pipe 7, has channels 14 and 15 located at different levels and directed into the furnace 10 at an angle / to each other. The air heater 9 is connected by air ducts 16.17 and 18 to the mill Z and the burners 11. In the channels 14 and 15 of the waste burner 13 gas-oil burners 19 and 20 are located.

The method is carried out as follows.

The coal from the hopper 1 is fed by a feeder 2 to the mill 3. Then the coal dust is transported by air to the cyclone 4, in which the main part of the dust (90%) is separated from the drying air.

Dust enters the dust bin 5, is dosed by the feeder 6 and transported to the burners 11 with hot air from the air heater 9,

The exhaust air with the remaining part of the dust (10%) after cyclone 4 enters through the pipeline 7 into the exhaust burner 13 by two flows through the channels 14 and 15, gas is supplied to both exhaust air flows through the burners 19 and 20, and the lower channel burner 19 14 gas is supplied with an excess of air of less than one.

The dust entering the furnace 10 through the burner 11 is burned up by the formation of flue gases containing nitrogen oxides.

Flue gases rising to the top of the furnace meet the torch of the burner 19, in which the dust burns out, containing in the stream of exhaust air entering the channel 14 of the exhaust burner 13.

In the torch of the burner 19, products of incomplete combustion of the fuel, for example, carbon monoxide and hydrogen, are formed due to a lack of air. Incomplete combustion products

fuels, in contact with nitrogen oxides, reduce the latter to molecular nitrogen.

Residues of products of incomplete combustion of fuel are burned in the upper part of the furnace

in the torch of the burner 20 in the stream of exhaust air entering the channel 15 of the waste heating pad 12. In this case, excess air is maintained in the burner 20 greater than unity. In general, for the exhaust burner 13, the ratio of air to additional high-calorie fuel (gas) is provided close to stoichiometric (a 1.0).

High-calorific fuel introduced into the furnace through burners 19 and 20 provides

afterburning of the dust entering the furnace with exhaust air, forming in the lower channel 14 of the exhaust burner 13 a reducing medium for nitrogen oxides in the flue gases from the flames of the main burners 11 and afterburning of products of incomplete combustion formed in the torch of the burner 19, in which the fuel burns with a lack of air.

Directional supply of both exhaust air flows to the furnace at an angle of one to

another prevents their premature interaction. Premature mixing of these streams reduces the efficiency of reducing nitrogen oxides in flue gases during the three-stage combustion of solid fuel.

Claims (1)

SUMMARY OF THE INVENTION A method for preparing and burning solid fuel by drying and grinding it, separating the resulting air mixture into dust, and exhaust air, followed by separation of the exhaust air into two streams and dust supply and both flows of exhaust air for combustion into the furnace, and the exhaust air flows into the furnace at different levels above the dust supply and additional high-calorific fuel is introduced into them, characterized in that, in order to reduce the formation of oxides, the exhaust air flows into the furnace downward and at an angle to each other, and in the lower stream dust is fed into the furnace with an excess of air less than unity. with / t