煤粉在富氧条件下燃烧特性的实验研究

STUDY OF OXYGEN CONTENT ON COMBUSTION CHARACTERISTICS OF PULVERIZED COAL

燃烧煤粉的锅炉在其点火和低负荷稳定运行时,需消耗大量的燃料油,因此有必要寻找更经济实用的解决办法。研究煤粉在富氧条件下的燃烧特性,不论对煤粉局部富氧的助燃还是煤粉的富氧点火技术都具有重要意义。该文采用德国Netzsch公司生产的STA409C型热天平研究了神木煤和蒲白煤3个不同粒度下的煤样在不同体积氧浓度下(20%、30%、40%、60%、100%)的燃烧行为。实验结果表明,随着氧浓度的增大,煤样燃烧分布曲线向低温区移动,煤样的着火温度及燃尽温度均呈下降趋势,着火时间提前且燃烧时间缩短,煤粉的综合燃烧特性指数有较大提高,并且,随煤粉粒径的增大,综合燃烧特性的改善更加明显。

It must consume vast oil when pulverized coal boilers ignite and low loads operate, so a more economical and applied method is necessary. Study of the combustion characteristics of pulverized coal at oxygen enrichment conditions is very important not only for combustionsupporting but also for ignition. In this paper, the results of a study on the combustion characteristics of Shenmu and Pubai pulverized coals under different oxygen volume content are presented by Netzsch STA 409 PC synchronization thermal analysis instrument. Non-isothermal thermo-gravimetry （TG/DTG） experiments were carded out for five oxygen content （20%, 30%, 40%, 60%, 100%） and three different size fractions（88-105μm,63-74μm, 〈 45μm respectively. Experimental investigation and theoretical analyzing has proved that there are great influences of oxygen content and particle size on ignitability of compositions, and till further influence combustion and burnout characteristics. The results generally show that with the oxygen content increases, TG curves of pulverized coals move to the lower temperature zone, and with higher the oxygen content, the lower the ignition and burnout temperature is, in addition, its combustion characteristics can be improved much more for larger particle sizes at oxygen enrichment conditions.