煤中水分变化对锅炉热效率的影响分析及修正计算

Influence Analysis of Coal Moisture Change on Boiler Thermal Efficiency and Its Correction Calculation

结合ASME PTC—2008《锅炉性能试验规程》中的修正方法,根据磨煤机热平衡及空气预热器热平衡原理,分析煤中水分减少对制粉系统调温风量、排烟温度的影响值及对锅炉热效率的修正影响值。通过分析得出,煤中水分减少,使进入锅炉制粉系统的调温风量增大,进入空气预热器的一次风量减少,从而影响了空气预热器的换热效果,使排烟温度升高,最终造成锅炉热效率降低。所采用的修正方法,全面考虑了煤中水分变化对锅炉调温风、排烟温度及锅炉效率的影响,为煤中水分减少对锅炉热效率影响的修正计算提供了依据,也为锅炉性能分析提供了计算依据。

Combined with the correction method in ASME PTC-2008 boiler performance test procedure,according to the thermal balance of coal mill and air preheater,the influence of moisture reduction on the temperature regulating air volume of coal pulverizing system and smoke exhaust temperature and the thermal efficiency of boiler were analyzed.According to the analysis,the moisture in coal decreases,so that the air quantity of regulating temperature into boiler pulverizing system increased and the air quantity into air preheater decreases.Therefore,the heat transfer effect of air preheater was affected,the exhaust temperature was raised,and the thermal efficiency of boiler was reduced.The modified method took into account the effect of moisture change in coal on the coal pulverizing system temperature regulating air,exhaust temperature and boiler efficiency.It provided a calculating basis for the correction of boiler efficiency by reducing water content in coal.It could provide calculation basis for boiler performance analysis.