CFB锅炉回料阀低频喘振的计算颗粒流体力学模拟  

CPFD simulation on low-frequency vibration of loop seal in CFB boilers

作　　者：曾胜庭 陈曦 马琎晨[2] 赵海波[2] ZENG Shengting;CHEN Xi;MA Jinchen;ZHAO Haibo(Guangdong Yudean Group Yunhe Power Co.,Ltd.,Yunfii 527328,China;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]广东粤电云河发电有限公司,广东云浮527328 [2]华中科技大学煤燃烧国家重点实验室,湖北武汉430074

出　　处：《热力发电》2018年第8期22-30,共9页Thermal Power Generation

摘　　要：本文采用计算颗粒流体力学(CPFD)方法对300 MW机组循环流化床(CFB)锅炉进行数值模拟,主要目的是分析CFB锅炉回料阀低频喘振的根源,并通过优化回料阀的操作参数减小其低频振动的可能性。首先针对CFB锅炉在运行时回料阀发生低频喘振的现象,对CFB锅炉整体进行了全床尺度的数值模拟,对锅炉内部的气固流动进行了分析,研究锅炉内部系统压力平衡、物料平衡和固相体积分数分布,模拟结果显示回料阀喘振的根本原因是,回料阀内部的流化风速过高,导致其中发生固相输运不畅甚至反吹现象,引起回料阀进口压力波动,产生喘振。其次针对回料阀组件进行模拟,线性调整回料阀的操作风速(返料风和松动风),分析不同工况下回料阀的内部气固流体动力学规律和固体循环流量,提供回料阀在变工况下的基础数据和操作特性,确定合适的回料阀操作风速区间。最后,按照优化的回料阀操作参数对整体CFB锅炉进行了模拟,模拟结果表明CFB锅炉运行平稳,回料阀的压力波动明显减小,低频振动得到很好的控制。A 300 MW circulating fluidized bed（CFB） boiler was simulated by computational particle fluid dynamics（CPFD） to investigate the reason of low frequency vibration of loop seal in the CFB boiler and reduce the possibility of low frequency vibration by optimizing the operating parameters of the loop seal. Firstly, for the low frequency vibration of the loop seal in the CFB boiler during operation, a full-scaled simulation of the CFB boiler was conducted to analyze the gas-solid flow inside the boiler. The pressure balance, material balance and solid volume fraction distribution inside the boiler were studied. The simulation results indicated that the root cause of the vibration of the loop seal was that the fluidized air velocity inside the loop seal was too high. It resulted in the occurrence of poor solid-phase transportation or even back-blowing, which caused the pressure fluctuation at inlet of the loop seal and vibration. Moreover, simulation of the loop seal component was conducted,the operating wind speed（return feed wind and loose wind） of the loop seal was adjusted linearly, the gas-solid fluid dynamics characteristic and solid circulation rate of the loop seal under different operating conditions were investigated, the basic data and operating characteristics of the loop seal under variable conditions were attained,and the appropriate operating wind speed interval of the loop seal was determined. Finally, the whole CFB boiler with optimized operating parameters of loop seal was simulated. The simulation results show that the CFB boilerran steadily. Especially, the pressure fluctuation at inlet of the loop seal obviously decreased and the low-frequency vibration of the loop seal was well controlled.

关 键 词：CFB锅炉 回料阀 CPFD模拟 气固流动特性 喘振 气体反窜 

分 类 号：TK175[动力工程及工程热物理—热能工程]