High-temperature and low-NOX combustion method and device for pulverized coal

Abstract

The invention provides a high-temperature and low-NOX combustion method for pulverized coal. The combustion method comprises the following steps that: pulverized coal enters a combustion device and then is burnt at high temperature; air input to the combustion device is input in a staged mode and a single or combined mode of direct flow and cyclone; a first larger return flow zone and a second larger return flow zone are formed in the combustion device by means of the use of the single or combined mode of the direct flow and the cyclone, wherein the first larger return flow zone is positioned on the front side of a pulverized coal conical spray combustion nozzle, and the second larger return flow zone is positioned in a zone relative to the other side of the combustion device with the pulverized coal conical spray combustion nozzle; NOX is prevented from being generated by inputting air by stages; and the generated NOX is reduced into N2 by forming gas return flow in the combustion device by means of the air cyclone input. The invention also provides the corresponding combustion device. The method and the combustion device have the advantages that: pulverized coal gas flow is easy to ignite; staged combustion and oxygen-depleted combustion are realized in the combustion device; the NOX emission load is low; the slag capture rate is high; the burn-off rate is high; the flame cleanliness is high; the capacity of adapting to different types of coal and load change is high; and effects of energy conservation and emission reduction are obvious.

Description

technical field [0001] The invention relates to a high-temperature and low-NO X The combustion method and device of the invention belong to the technical field of pulverized coal clean combustion. Background technique [0002] Nitrogen oxides (NO X ) is considered to be one of the main sources of air pollution, NO X In addition to forming acid rain and destroying the ecological environment, it can also form photochemical smog, which directly endangers human health. Currently, NO X In our country has become second only to SO 2 air pollutants. my country is a developing country that uses coal as the main energy source. It is estimated that the structure of coal as the main energy source will not change in the next 30 to 50 years. Burning coal will produce a lot of NO X , increasingly stringent environmental regulations require research and development of advanced combustion technologies to reduce NO X emissions of pollutants. Now control NO X The most effective way i...

AI Technical Summary

Problems solved by technology

[0007] In existing coal-fired boilers, to achieve low NO X The purpose of emission will bring the following problems: (1) The burnout rate of carbon decreases, which reduces the boiler efficiency; (2) CO emissions increase; (3) Low NO X Combustion leads to changes in the characteristics of fly ash, making it difficult to reuse fly ash; (4) Low NO X Combustion creates a local strong reducing atmosphere in the furnace, which increases the possibility of furnace slagging; (5) Low NO X The reducing atmosphere caused by combustion increases the tendency of high temperature corrosion of the furnace water wall

Therefore, controlling NO in the combustion process X The principle of reducing the amount of generation used is often in contradiction with the principle of reducing the carbon content of fly ash and increasing the burnout rate of pulverized coal boilers. At the same time, it has high efficiency, stable combustion, anti-slagging, anti-high temperature corrosion and low-pollution pulverized coal combustion. The technology is still blank in our country, because the requirements of these five aspects are often contradictory and difficult to meet at the same time

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