深度调峰状态下锅炉尾部烟道积灰预测及防治

Prediction and Prevention of Ash Accumulation in Boiler Tail Flue of Deep Peak Shaving

随着新能源装机容量逐渐增加,亟需火电机组通过深度调峰来提高电网大规模消纳新能源能力。锅炉低负荷运行时,烟气流速偏低,烟气携带灰能力降低,容易在尾部烟道局部区域形成积灰,影响尾部烟道的安全。而早年投入运行的火电机组在设计之初只考虑50%以上负荷的正常运行,因此在当前深度调峰状态下,需要根据实际情况对锅炉尾部烟道进行安全性评估,防止锅炉长期低负荷状态下运行出现尾部烟道积灰引起的安全事故。根据气力输灰理论,分别给出尾部烟道水平段、倾斜段和垂直段防止飞灰在管道内沉积的终端速度,并结合某电厂烟道实际情况,进行烟道流场数值模拟分析,判断深度调峰状态下锅炉尾部烟道积灰情况,为机组的安全运行提供指导意见。

With the gradual increase of new energy installed capacity,thermal power units are urgently needed to improve the large-scale consumption of new energy by thermal power units through deep peak shaving.When the boiler runs under low load,the flow rate of flue gas is low,the ash carrying capacity of flue gas is reduced,which is easy to form ash accumulation in the local area of the tail flue,affecting the safety of the tail flue.However,the thermal power units put into operation in the early years only considered the normal operation of more than 50%load at the beginning of design.Therefore,under the current deep peak shaving,it is necessary to conduct safety assessment on the tail flue of the boiler according to the actual situation,so as to prevent safety accidents caused by ash accumulation in the tail flue under the long-term low load state of the boiler.According to the theory of pneumatic ash transport,the terminal velocity of horizontal,inclined and vertical sections of the tail flue to prevent the deposition of fly ash in the pipeline is given respectively.Combined with the actual situation of the flue of a power plant,carrying out numerical simulation analysis of flue flow field,judging the ash accumulation in the boiler tail flue under deep peak regulating state,and provide guidance for the safe operation of the unit.