Combustion method that can effectively reduce boiler furnace slagging

Abstract

The invention relates to a combustion method capable of effectively reducing slagging of a boiler hearth. Electrical energy is mainly obtained through thermal power generation of fire coal, power coalin China mostly is inferior coal, and slagging of a hearth during combustion is a problem plaguing the running of a power plant for a long time; and at present, a concentrated arrangement manner is adopted for combustors, the combustion temperature of pulverized coal is high, the slagging condition of a water-cooling wall of the boiler hearth is worsened, and the high-temperature corrosion of thewater-cooling wall is intensified. According to the combustion method, from composition, main combustors are comprised, each main combustor comprises a group of primary air nozzles and secondary airnozzles which are arranged at intervals, horizontal concentrated-dilute nozzles are selected as the primary air nozzles, the spiral directions of the secondary air nozzles are parallel to the centralaxes of the combustors, and the sprayed gas flow is parallel to the central axes of the combustor; and the main combustors are installed at the four corners of the boiler hearth, the central axes of the corner combustors and the water-cooling wall of the hearth form included angles alpha, and a small imaginary tangent circle is formed, so that the slagging and the high-temperature corrosion of thewater-cooling wall are effectively avoided. The invention relates to a combustion method capable of effectively reducing slagging of a boiler hearth.

Description

[0001] Technical field: [0002] The invention relates to a combustion method capable of effectively reducing boiler furnace slagging. [0003] Background technique: [0004] Power energy is mainly coal-fired thermal power generation. Most of the power coal used in my country is low-grade and inferior coal. Slagging in the furnace during boiler combustion is a long-term problem that has plagued the operation of power plants. Currently, the burners are arranged in a centralized manner, and the pulverized coal combustion temperature If the temperature is higher, the slagging of the water wall of the boiler furnace will deteriorate, and the high temperature corrosion of the water wall will intensify. [0005] Studies have shown that boiler slagging is caused by the flue gas with a temperature higher than the ash melting point scouring the heating surface of the boiler, and the molten ash in the flue gas adheres to the heating surface. Fly ash in the furnace area exists in a molten...

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Problems solved by technology

[0004] Power energy is mainly coal-fired thermal power generation. Most of the power coal used in my country is low-grade and inferior coal. Slagging in the furnace during boiler combustion is a long-term problem that has plagued the operation of power plants. Currently, the burners are arranged in a centralized manner, and the pulverized coal combustion temperature Higher, the slagging of the water wall of the boiler furnace will deteriorate, and the high temperature corrosion of the water wall will intensify

[0005] Studies have shown that boiler slagging is caused by the flue gas with a temperature higher than the ash melting point scouring the heating surface of the boiler, and the molten ash in the flue gas adheres to the heating surface. Fly ash in the furnace area exists in a molten or semi-molten state. When this type of molten fly ash passes through the heating surface, it condenses and continuously thickens and accumulates on the heating surface, eventually forming slagging; slagging is not only related to the special effect of coal ash, but also It is closely related to the combustion status of the boiler and the structural layout of the boiler. At present, due to the emission of pollutants from boiler combustion, the environmental protection department has increasingly paid attention to it. The latest standards require that the NOx emission of coal-fired thermal power boilers is lower than 50mg / Nm3. Most coal-fired boilers Using staged combustion technology, the most common method at present is to carry out air depth staged combustion in the direction of furnace height. Specifically, the air required for pulverized coal combustion is divided into two stages and sent to the furnace. The first stage sends air into the main In the combustion zone, the excess air ratio in this zone is controlled between 0.6 and 0.9, and the fuel burns in an oxygen-deficient and fuel-rich atmosphere to suppress the formation of NOx. The second stage sends air into the burnout zone to control the air in this zone. The excess air ratio is between 1.15 and 1.25, forming oxygen-enriched combustion, which is conducive to the burnout of pulverized coal. This technology has achieved a good effect of low NOx emissions. The melting point of coal ash is lowered, the burners are arranged in a centralized way, the combustion temperature of pulverized coal is higher, the slagging of the water wall of the boiler furnace is worsened, and the high temperature corrosion of the water wall is intensified

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