RU2638898C1 - Method of steam boiler operation - Google Patents

Abstract

FIELD: heating system.

SUBSTANCE: method of steam boiler operation, after which air and natural gas used as fuel are fed into furnace, the warmth of products of combustion is derived to boiler water and steam, after which the outgoing gases are removed from the boiler to atmosphere, blowoff water is derived from boiler drum. Blowoff water is injected in the furnace of boiler, thereby reducing the temperature of combustion products and suppressing the formation of nitrogen oxides in the furnace, the amount of the injected blowoff water is controlled by the pulse from the temperature sensor of combustion products in the most heat stressed part of the furnace, the outgoing gases are cooled below the condensation temperature of water steam, formed during the injection of blowoff water into the furnace, and the condensate formed during the cooling of outgoing gases is used in the steam-water cycle of the boiler, for example, is fed into the feedwater deaerator.

EFFECT: decrease in temperature in the most heat-stressed part of the furnace and prevention of formation of nitrogen oxides.

1 dwg

Description

The invention relates to the field of power engineering and can be used to improve environmental safety and efficiency of a boiler plant.

An analogue is known - the method of operation of a steam boiler, according to which fuel and air are supplied to the furnace of a steam boiler, fuel combustion products give heat to the boiler water and steam, after which the exhaust gases are removed from the boiler to the atmosphere, purge water is removed from the boiler drum (see book. Nemtseva Z.F., Arsenyeva G.V. “Thermal power plants and heat supply”, Moscow: Energy Publishing House, 1982. Fig. 16.1.1 on p. 258 and a description on it on p. 257-263). This analogue is adopted as a prototype.

The disadvantages of the analogue and prototype are the reduced cost-effectiveness and environmental safety of the boiler plant due to the formation of a large amount of nitrogen oxides NO _x in the boiler furnace during fuel combustion, especially when burning fuel oil. The intensity of NO _x formation is directly related to the temperature regime of the furnace.

The technical result achieved by the present invention is to increase the environmental safety and efficiency of the boiler by lowering the temperature in the most heat-stressed part of the furnace and preventing the formation of nitrogen oxides during economic operation of the boiler plant.

To achieve this result, a method for operating a steam boiler is proposed, in which fuel and air are supplied to the furnace of a steam boiler, fuel combustion products give heat to the boiler water and steam, after which the flue gases are removed from the boiler to the atmosphere, purge water is removed from the boiler drum.

The peculiarity lies in the fact that purge water is injected into the furnace of the boiler, which reduces the temperature of the combustion products of the fuel in the most heat-stressed part of the furnace and suppresses the formation of nitrogen oxides in the furnace, the amount of injected purge water is regulated by the pulse from the sensor of the content of nitrogen oxides in the exhaust gases of the boiler, the flue gases are cooled below the condensation temperature of water vapor generated by injection of purge water into the furnace, and the condensate formed during cooling of the flue gases is used They are fed into the steam-water cycle of the boiler, for example, fed to the deaerator of feed water.

The proposed set of features of the claimed method allows to reduce the formation of NO _x in the furnace by lowering the temperature in the most heat-stressed part of the furnace during economic operation of the equipment.

Next, we consider the information confirming the possibility of carrying out the invention with obtaining the desired technical result.

The drawing shows a schematic diagram of a boiler plant. The boiler installation contains a steam boiler 1 with a furnace 2. A purge water pipe 4 is connected to the drum 3 of a steam boiler 1, which is connected to a nozzle 5 for injecting purge water into the furnace 2. A control valve 6 is installed on the pipe 4 and is connected to the regulator 7 for the content of nitrogen oxides in flue gases. The controller 7 is connected to a sensor 8 for the content of nitrogen oxides NO _x in the exhaust gases. The steam boiler 1 is connected to the chimney 9 with a gas duct 10 in which a sensor 8 is installed. A condensation heat exchanger 11 installed at the outlet of the flue gases from the convective part of the steam boiler 1 is connected to a deaerator 12 by a condensate line 13. A pipe 14 of chemically cleaned additional gas is also connected to the deaerator 12 feed water connecting the deaerator 12 with the water treatment plant 15.

The method of operation of a steam boiler is as follows.

Fuel and air are supplied to the furnace 2 of the steam boiler 1, and as a result of fuel combustion, steam is generated which is released in the drum 3. From the drum 3 of the steam boiler 1, purge water is withdrawn via a pipe 4. Combustion products are removed by a smoke exhauster through a flue 10 through a chimney 9 to the atmosphere. The pulse from the sensor 8 of the content of nitrogen oxides NO _x installed in the duct 10, the regulator 7 changes the position of the control valve 6 and, therefore, the amount of injected purge water through the nozzle 5. The flue gases are cooled below the condensation temperature of the water vapor contained in the flue gases, condensation heat exchanger 11. Condensate formed during cooling of the exhaust gases is fed through the condensate line 13 to the deaerator 12, due to which the heat of condensation and the mass of water vapor generated When injected into the furnace 2 blowdown water. If necessary, in the deaerator 12 serves additional feed water prepared in the water treatment plant 15.

Note that the condensate of water vapor is much cleaner than the purge water from which these vapors are formed, which allows us to completely utilize the heat and mass of these vapors in the feed water cycle of the steam boiler.

Maintaining a predetermined temperature of the fuel combustion products in the most heat-stressed part of the furnace, excluding the formation of nitrogen oxides in the furnace, due to the controlled injection of purge water and the utilization of the mass and heat of condensation of the water vapor generated in this process, can increase the environmental safety and efficiency of the boiler plant and reduce harmful anthropogenic effects to the climate system by eliminating NO _x emissions into the atmosphere during economical operation of boiler plant equipment.

Claims (1)

The method of operation of a steam boiler, in which air and natural gas used as fuel are supplied to the boiler furnace, the heat of the fuel combustion products is removed to the boiler water and steam, after which the exhaust gases are removed from the boiler to the atmosphere, purge water is removed from the boiler drum, characterized in that that purge water is injected into the furnace of the boiler, due to which the temperature of the combustion products of the fuel in the most heat-stressed part of the furnace is reduced and the formation of nitrogen oxides in the furnace is suppressed, the amount of injected purge water p The pulse is regulated by a pulse from the sensor of the content of nitrogen oxides in the boiler flue gases, the flue gases are cooled below the condensation temperature of the water vapor generated by injection into the furnace of purge water, and the condensate formed during cooling of the flue gas is used in the boiler water-steam cycle, for example, it is fed into the feed water deaerator.

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