四角切圆锅炉温度场闭环控制研究

Study on Tangential Boiler Temperature Field Using Closed-Loop Control

电站锅炉炉膛温度场与煤粉燃烧、工质吸热、NO_x生成及积灰结渣的形成等密切相关,易受到某些未知因素的影响而遭到破坏,进而影响锅炉的安全、稳定运行。对某电厂2号锅炉在300 MW、270 MW、240 MW 3个工况下进行了燃烧调整试验,利用声波测温系统实时采集温度,并将数据处理结果以偏置信号的形式加在原有的信号上,通过控制二次风门开度的大小对温度场均衡性和NO_x排放浓度进行闭环控制优化。试验结果显示,锅炉温度场均衡性变好,NO_x排放浓度降低。该研究解决了温度场只能依据操作人员经验进行调整的不灵活性问题,提高了锅炉控制的智能化程度,对优化燃烧有着重要参考价值。

The boiler furnace temperature field is determined by coal combustion, working medium heat absorption, NOx generation, as well as fouling and slagging, etc. It tends to be damaged by some uncertain factors, which will eventually affect the safe and stable operation of boilers. Therefore, the combustion adjustment experiment is performed at the load level of 300 MW, 270 MW and 240 MW respectively on Unit 2 of a power plant, and the real-time temperature data are collected by the acoustic temperature measurement system. Then, the processed data results are superimposed onto the original signals in the form of bias signals. By controlling the secondary air door opening size, the balance of temperature field and NOx emission concentration are optimized in closed-loop control. The experiment results show that the temperature field balance has been improved and the NOx emission concentration is also reduced eft-ctively. Through this study the issue of lacking flexibility in manual adjustment based on operators＇ experience is resolved. The intelligent level of the boiler control is also improved, which is very helpful for combustion optimization.