火电厂入炉煤低位热值实时测量的研究及其应用

Research and Application of Real-Time Measurement for Lower Calorific Value of Burning Coal in Coal-Fired Power Plants

在电厂燃煤煤种杂、煤热值波动大的背景下,锅炉正平衡煤耗计算结果的准确性成为难题。为此,利用设计资料中机组负荷与设计煤种煤量的对应关系以及实际负荷、实际煤量、设计煤种低位发热量等指标,通过锅炉燃煤技术指标建立模型测算燃煤热值;在机组协调控制系统(coordinated control system,CCS)中增加燃煤的实时热值修正回路,用燃煤的实时热值进行汽温、汽压调节,有效地改善了自动发电控制(automatic generation control,AGC)性能;针对机组辅机故障减负荷功能(run back,RB)在燃煤热值大幅度变化时存在目标煤量不能与负荷完全对应的隐患,利用RB动作前燃煤的实时热值及时修正RB目标煤量,确保RB目标煤量全工况适应煤质变化,与RB目标负荷相对应,提高了RB的动作正确率;用软测量所得的煤实时热值代替化验值,在耗差分析系统中实时计算正平衡煤耗,大幅度提高了煤耗计算的准确性。目前,该方法在大唐国际系统中的所有火电企业中得到推广应用。

Due to the complexity of coal type and the large fluctuations of coal calorific value in power plant, the calculation of positive balance coal consumption has difficulty in accuracy. Therefore, by using the corresponding relation between load and the amount of design coal in design data, as well as the actual load, the actual amount of coal, the design lower calorific value of coal, the prediction model of coal＇s calorific value was built based on the technical indicators of coal-fired boiler. The corrective loop for the real-time calorific value of burning coal was increased into the coordinated control system （ coordinated control system, CCS） of units, and the real-time calorific value of burning coal was used for the regulation of steam temperature and pressure, which could effectively improve the performance of automatic generation control （AGC）. To the problem that the target coal amount of run back （ RB ） could not completely correspond with load when the calorific value of burning coal changed greatly, the real-time calorific value of burning coal was used before RB action to correct the target coal amount of RB, which ensureed that the target coal amount of RB in all conditions could meet the changes of coal quality, and could correspond with the target load of RB and improve the operation accuracy of RB. During the real-time computing process of positive balance coal consumption in energy loss differential analysis system, the test value was replaced by coal＇s real-time calorific value measured in soft-sensing, which could greatly improve the accuracy of coal consumption calculation. At present, the project has been widely promoted in all thermal power enterprise of Datanglnternational system.