煤质特性对燃煤电厂炉型选择的影响

Influence of coal quality characteristics on the choice of boilers in coal-fired power plant

对某新建电厂拟用煤种的煤质特性进行了分析,发现设计煤种、校核煤种Mt都超过了31%,采用煤粉炉炉型时,选择中速磨制粉系统应特别慎重;设计煤种具有轻微结渣、中度沾污倾向,校核煤种具有严重结渣、高度沾污倾向,设计、校核煤种分别属于中等结渣和易结渣煤种;设计、校核煤种属低挥发分褐煤,热值均较低。以煤质特性为基础,从燃料水分、灰渣特性、挥发分和发热量、煤灰CaO含量等方面对电厂锅炉炉型进行了选择。结果表明:与煤粉炉相比,循环流化床(CFB)锅炉对煤种适应性更强,可大幅降低燃用煤种的结焦风险,且低负荷稳燃特性良好;CFB锅炉+干法脱硫除尘一体化的布置方式可充分利用灰中CaO,节约脱硫用石灰石耗量,降低投资。最后通过对CFB锅炉的优势分析,说明其具有燃料适应性好、负荷调节范围广、清洁高效燃烧和运行周期长等优点,对于设计、校核煤种来说,CFB锅炉是更好的选择。

The analysis of coal quality characteristics which is going to apply in newly-built power plant indicates that the Mt of design coal and check coal are more than 31 percent, so caution should be used when choosing the type of pulverized coal furnace and medium speed grinding system. The design coal tends to slightly slag and moderate contaminate, while the check coal is inclined to serious slag and highly contaminate. Both are low volatile lignite, the calorific value are poor. Based on the coal quality, fuel moisture, slag characteristics, volatiles, calorific value and CaO content in coal ash, chose the type of boiler. The results show that, compared with pulverized coal furnace, CFB boiler has better coal applicability and stable combustion performance under low load condition, which avoid the slagging. The combination of CFB and dry desulfuration dedusting system makes full use of CaO in coal ash, reduces the additional CaO consumption. The CFB boiler has lots of advantages such as great coal applicability, broad load control range, long cycle of operation which are the right furnace for design coal and check coal.