以侧煤仓布置的1000MW对冲锅炉制粉系统为研究对象,分析粉管粉量、煤粉细度和粉管综合阻力的分布规律。发现粉量和煤粉细度分布大体呈现倒“N”型趋势。粉量大的粉管,其煤粉细度大;粉量少的粉管,其煤粉细度小,二者呈现正相关。粉管综合阻力呈现“N”型分布,与粉量、煤粉细度分布呈负相关。各粉管粉量分布趋势由粉管综合阻力不同导致,磨煤机参数的变化不改变这种分布规律。1号机组制粉系统粉量最大偏差为37.7%,2号机组制粉系统粉量最大偏差为84.4%,均远超规程要求的±10%偏差内。动态分离器厂家不同,其分离效果存在优劣,导致粉量偏差程度不同。粉量分布特点要求燃烧器配风必须针对性进行调整。提高旋流强度、开大二次风量、关小燃尽风、提高运行氧量等措施利于缓解偏烧。粉量大的燃烧器,其内二次风量开大、外二风量关小。低负荷奇数台磨煤机运行时,针对性提高粉量偏差最大磨煤机的风煤比。单台单侧运行的磨煤机掺烧难燃煤种或降低分离器转速以提高其火焰中心。燃烧调整试验后,1号机组偏烧问题得到解决,2号机组由于粉量偏差大仍存在一定程度偏烧。对于粉量偏差过大的制粉系统,可通过煤粉侧和二次风侧的改造彻底解决偏烧问题。粉量分布特性和优化调整思路为同类型机组解决偏烧问题提供参考。

tribution laws of powder quantity, fineness of pulverized coal and comprehensive resistance of powder tubes were analyzed. It is found thatthe distribution of powder quantity and pulverized coal fineness show an inverted " N" trend generally. The powder pipe with large amountof powder has a large fineness of pulverized coal while the pulverized coal fineness of the powder pipe with less powder quantity is small.The powder quantity and the pulverized coal fineness are positively correlated. The comprehensive resistance of powder tubes shows an“N” trend, which is negatively correlated with the powder amount and the fineness distribution of the pulverized coal. The powder distribution trend of powder tubes are caused by the different comprehensive resistance of powder tubes. The change of mill′s parameters doesnot affect this distribution law. The maximum deviation of powder amount on No.1 unit is 37.7% while the maximum deviation of powderamount on No.2 unit is 84.4%, which are far beyond the ±10% deviation required by the regulations. Different manufacturers of dynamicseparators has different separation effects which result in different degrees of powder deviation. The characteristics of powder distributionrequire that the air distribution of burner must be adjusted accordingly. Measures such as increasing the swirl intensity, opening of the secondary air, turning off of the burning wind, and increasing of the operating oxygen are helpful to alleviate the partial combustion. For theburner with large amount of powder quantity, its internal and external secondary air volume and swirl intensity should be enlarged correspondingly. When the low load and odd number coal mills was running, the air-coal ratio of the coal mill with the largest deviation of thepowder amount should be improved. A single unilaterally operated coal should be blended difficult-to-burn coal or reduces the separatorspeed to increase its flame center. After the combustion adjustment, the partial combustion problem of unit 1 is solved while the unit 2 stillhas slight partial combustion due to the large deviation of powder quantity. For the pulverizing system with excessive powder deviation, theproblem of partial burning can be completely solved by the transformation of the pulverized coal side and the secondary air side. The characteristics of powder distribution and the optimization adjustment strategies provides a reference for the same type of units with partial burning.

0 引言

1 试验

2 试验方法

3 制粉试验结果

4 燃烧优化调整

   4.1 燃烧优化思路

   4.2 省煤器出口烟气成分对比

   4.3 炉膛温度对比

5 改造建议

6 结论