Thick and thin separation rotational flow pulverized coal burner

Abstract

The invention discloses a thick and thin separation rotational flow pulverized coal burner. The thick and thin separation rotational flow pulverized coal burner comprises a primary air passage, an inner secondary air passage and an outer secondary air passage which are coaxially arranged in sequence from outside to inside, wherein an inlet is formed in one end of the primary air passage, an outlet is formed in the other end of the primary air passage, a guide device used for guiding pulverized coal to the center of the primary air passage is arranged inside the primary air passage, and a contraposition air-distribution taper is arranged between the guide device and the outlet. The arranged contraposition air-distribution taper utilizes the inertia of the pulverized coal, further processes the pulverized coal airflow guided to the center, separates the pulverized coal and primary air as much as possible, forms efficient thick and thin separation, and is good in final thick and thin separation effect.

Description

technical field [0001] The invention relates to the field of pulverized coal combustion, in particular to a pulverized coal burner with thick-thin separation swirling flow. Background technique [0002] Thermal power plants account for more than 80% of my country's power industry. With the establishment of large-scale thermal power plants in my country in recent years, almost all boilers of large-scale units use pulverized coal as fuel. For a long time, the reality of various types of coal used by boilers, poor coal quality, and tight supply and demand have brought many problems to the operation of pulverized coal boilers designed according to a single type of coal, directly affecting the safe and economical operation of the boiler. Especially in 2011, the state issued the "Emission Standard of Air Pollutants for Thermal Power Plants" (GB13223-2011), which strictly controls the NOx emissions of thermal power plants. The technological transformation of the nitrogen combusti...

AI Technical Summary

Problems solved by technology

The distribution of pulverized coal that is dense on the outside and light on the inside is conducive to the stable combustion of the fire. The dense pulverized coal can be heated by the high-temperature backflow flue gas in time, and can be mixed with the secondary air to supplement oxygen in time for combustion. Mixed with the secondary air, the volatile matter in the coal is precipitated and it is difficult to maintain an oxygen-poor environment during combustion, and the precipitated nitrogen-containing reducing elements are less, which is not conducive to reducing the formation and emission of nitrogen oxides

For the distribution of pulverized coal with inner concentration and outer thinness, the pulverized coal is concentrated toward the central axis of the nozzle, and is mixed and heated with the hot flue gas returning from the center in time. At this time, in an oxygen-deficient environment, a large amount of nitrogen-containing reducing elements will be precipitated from the volatile matter. It is very beneficial to reduce the generation and emission of nitrogen oxides, but it is easy to supplement oxygen in time, which is not good for stable combustion. When the coal type or load fluctuates, it is easy to turn off the flame, and the adaptability of the coal type is not strong.

[0004] For the swirl pulverized coal burners currently used in the market, no matter whether they are the type with thick outer and thin inside or the type with thicker inner and outer thin, there is generally the problem of poor separation of thick and light. For example, the concentrated ring swirl pulverized coal burner While the powder is directed to the center of the primary air duct, most of the primary air is also directed to the center. Although the primary air will diffuse after passing through the concentrator, the natural diffusion of the airflow perpendicular to the flow direction is relatively slow, so after passing through the concentrator ring , increase the primary wind speed in vain, but the actual thick-thin separation effect is not good, which is not good for stable combustion and reduction of nitrogen oxides. NOx capabilities will be greatly enhanced

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