空气预热器出口烟气温度及氧含量分布特性

Flue Gas Temperature and Oxygen Content Distribution Characteristic at Exit of Air Preheater

通过在电厂进行的大量试验中获得的试验数据进行整理,分析和总结,获得空气预热器出口烟气温度和氧含量的分布特性。试验发现空气预热器出口的烟气氧含量呈现出两种分布特性规律。空气预热器出口烟气氧含量呈现哪一种分布特性规律取决于空气预热器漏风情况,是携带漏风还是间隙漏风的占主导地位。烟气的温度分布也具有一定的规律特性。空气预热器出口的烟气温度分布特性显然与空气预热器转子的转动以及漏风、传热等因素有关。试验结果显示:空气预热器出口的烟气含氧量与CO含量呈现较好的指数型关系,烟气的CO含量随着烟气的含氧量增加而降低。这种规律特性与煤粉的燃烧耗氧量和混合特性有关。基于这种规律,合理布置传感器,其测量烟道断面平均值的精度能够控制在3%的范围内,传感器基本安装在空气预热器中间位置及其附近,有时传感器的布置需要因地制宜。

A large number of experimental data were gained from a lot of experiments in power plants. These experimental data was collected and analyzed in this paper. The law of oxygen content and temperature distribution of flue gas in the exit of air pre-heater were pro- posed and showed basis on these experimental data. It is found two different laws for oxygen content distribution of flue gas in the exit of air pre-heater. The oxygen content distribution law of flue gas depends on air leakage situation of the air pre-heater, which is dominated by entrained leakage or gap leakage. It has its own law for the flue gas temperature distribution at the exit of air pre-heater. The flue gas temperature distribution is related with rotation of the rotor, air leakage and heat transfer. The results indicate there is an exponent relationship between the O2 content and the CO content of the flue gas at the exit of air pre-heater. The CO content of flue gas is decreased with the increasing of the O2 content. The law depends on needs of O2 for pulverized coal and mixture characteristic of O2 and coal. Based on this rule, the measuring accuracy of parameter average in the flue cross section is in the range of 3 % by reasonably placing the sensors. The sensors were all installed nearby and in the middle of air pre-heater. But sometimes the sensors are needed to be adjusted to a different place.