Annular return type lignite swirl burner and combustion method

Abstract

The invention discloses an annular reverse flow type lignite cyclone burner, which comprises a burner wind box, a central wind pipe, a primary wind pipe, a secondary wind pipe, a secondary wind whirlcone, a tertiary wind pipe and a tertiary wind whirlcone, wherein a spout at the front end of the secondary wind pipe is provided with a secondary wind expansion cone; a spout at the front end of the tertiary wind pipe is provided with a tertiary wind expansion cone. The annular reverse flow type lignite cyclone burner is characterized in that the front end of the primary wind pipe is provided with a section of conical retraction spout; a secondary wind partition panel is also arranged between the primary wind pipe and the spout of the secondary wind pipe. The invention also discloses a burning method of the burner. By using the annular reverse flow type lignite cyclone burner and the burning method of the burner, the stability and the reliability of an entire burning system can be guaranteed in the working condition that a primary wind rate is too big; a low-NOx burning effect is realized.

Description

technical field [0001] The invention relates to an annular backflow swirl burner and a combustion method for lignite. Background technique [0002] For high-moisture lignite, although it is easy to ignite and stable-combustible in terms of volatile content, lignite itself also has the characteristics of low calorific value and high moisture, and often has the characteristics of excessive primary air rate; On the one hand, although lignite is a coal that is extremely easy to burn out, it is also greatly affected by the combustion temperature level in the boiler furnace. It is necessary for the pulverized coal particles to have sufficient residence time in the furnace so that the pulverized coal can be fully burned out; [0003] Due to the particularity of lignite, the primary air rate is large, the coal moisture content in the primary air is high, the oxygen content in the primary air is reduced, and the water vapor content is high. The radiant heat in the pulverized coal fir...

AI Technical Summary

Problems solved by technology

As for the two forms of flue gas reflow: one is the central recirculation area, the other is the annular recirculation area; for the existing traditional swirl burner for burning bituminous coal, because of its own easy ignition, it can be used in the annular reflow area. Relatively stable combustion can be obtained with a small area and a small flue gas return flow, while the traditional swirl burner for burning lignite, due to the small annular return area, it is very easy for the flue gas return flow to be insufficient to support high moisture The stable combustion of low calorific value lignite causes extremely serious flame delay, which affects the stability and reliability of the entire combustion system; and the combustion flame includes the intermediate reduction zone and the peripheral oxygen-enriched zone, and the formation of nitrogen oxides (NOx) is mainly in the fuel-rich and In the junction area of ​​the oxygen-enriched zone, the expansion of the reduction zone also has a good reduction effect on the NOx in the main generation zone, and the expansion of the reduction zone requires a larger annular recirculation zone to achieve, so the conventional smaller annular recirculation zone cannot effectively organize Form the low NOx combustion effect of reducing NOx in the flame, and cannot realize the stable combustion of lignite and the effect of reducing NOx

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