Monitoring of evaporating tube wall temperature mainly relies on a certain number of thermocouples outside the furnace and it lacks effective methods inside the furnace. Through the modeling of wall heat transfer, furnace heat flux distribution and tube dimension as well as the simulation of forced convective boiling heat transfer in the wall tubes, online measurement of the whole-furnace evaporating wall temperatures and the firing coal calorific value is achieved with a monitoring and forecasting system successfully developed and applied for a 1 000-MW supercritical boiler. The performance tests on the system are carried out, which show that the difference between the on-line monitoring value and the value measured by the thermocouples ranges from -2.47% to +3.83% and the error of the on-line monitoring of the coal low calorific value on as-received basis ranges from -6.99% to +5.32%.%超临界压力直流锅炉蒸发受热面壁温监测主要依靠布置在炉膛外的少量热电偶,炉内管壁温度缺乏有效的监测手段.通过对超临界压力直流锅炉蒸发受热面传热、炉膛热流量分布、蒸发管参数建模以及受热管内强制对流沸腾换热的模拟,实现了全炉膛蒸发受热面管壁温度和燃煤发热量的在线测量.开发的超临界压力直流锅炉炉膛受热面壁温监测预报系统在一台1 000MW应用成功.采用试验方法测试了系统的性能,结果表明,炉外壁温的测量值与预测值的偏差在-2.47％～+3.83％,煤收到基低位发热量的监测误差在-6.99％～+5.32％.
展开▼
