双通道低氮煤粉燃烧器飞灰碳形成机理的研究

INVESTIGATION OF DUAL CHANNEL LOW NO_x PULVERIZED COAL COMBUSTOR FLY ASH CARBON FORMATION

为克服燃煤发电过程排放的NOx对人体和环境的危害,低氮煤粉燃烧器得到广泛的使用.但如果低氮煤粉燃烧器利用不当,会造成飞灰碳的大幅增加.利用筛分法和烧失量法研究双通道低氮煤粉燃烧器飞灰碳的分布特性,利用压汞仪和XRD分析飞灰碳的失活程度,从而研究双通道低氮煤粉燃烧器飞灰碳升高的原因.结果表明,双通道低氮煤粉燃烧器飞灰碳为双峰分布,小粒径飞灰碳失活不明显,大粒径飞灰碳失活明显.分析原因后认为:小粒径煤粉颗粒在燃烧区域停留时间过短,没有完全燃烧;大粒径煤粉颗粒在高温乏氧区域停留时间过长导致的失活是双通道低氮煤粉燃烧器飞灰碳升高的主要原因.

In order to decreasing the pulverized coal thermal power plant NOx emission damage to human and environment, low NOx pulverized coal combustors are utilized widely. But if the low NOx pulverized coal combustors are operated incorrectly, the fly ash carbon will increase significantly. In the paper, the screen separation and loss of ignition are used to study the fly ash carbon distribution, mercury intrusion and X-ray diffraction are used to study the fly ash carbon inactivation, so as to analysis the reasons of the very high fly ash carbon in dual channel low NOx pulverized coal combustors. It is showed that the dual channel low NOx pulverized coal combustor fly ash carbon distribution has two pinks and the big particle size fly ash carbon inactivation is more significant than that of the small. The author believed that incomplete combustion due to short residence time in combustion zone of small pulverized coal particle and the inactivation due to long residence time in anaerobic and high temperature zone of big pulverized coal particle lead to the increasing of fly ash carbon in some dual channel low NOx pulverized coal combustors.