双支腿循环流化床炉膛翻床条件与防止控制试验研究
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摘要
在双支腿循环流化床冷态试验台上进行了床料平衡试验,得到不同流化参数下风量和床压的动态曲线,基于并行流道阻力特性分析,提出双支腿炉膛翻床条件的预测方法,并模拟了控制逻辑对翻床的控制效果.结果表明:当流化风量大于临界翻床风量时,双支腿炉膛处于自平衡区,两侧炉膛的流化风量和床压的瞬时偏差能够相互纠正,两侧床料处于动态平衡;当流化风量小于临界翻床风量时,将发生翻床现象;临界翻床风量随着静止床料高度的增加而减小;采用调整风门开度的方法解决翻床问题存在局限性,床料平衡的首要策略是使双支腿系统处于自平衡状态运行.
Experimental tests were conducted to study the bed material balance in a cold circulating fluidized bed(CFB)test rig with breeches-legs,during which dynamic curves of air flow rate and bed pressure were obtained under different fluidization parameters.Based on theoretical model of parallel flow,the overturn condition in breeches-legs CFB was predicted,while the effects of control system simulated.Results show that the breeches-legs furnace will work in the self-balance zone if the fluidization air rate exceeds the critical value,in which case,the instantaneous deviation of air flow rate and bed pressure at both sides of the furnace will redress with one another and the bed material in both legs will be in dynamic balance.Bed inventory overturn occurs under the condition the total fluidization air rate being less than the critical data. The critical air flow rate decreases with rising static bed height.The method by adjusting valve opening to control the bed inventory overturn has its limitations.The most important way to control bed inventory overturn is to make the breeches-legs system operate in a self-balance state.
Experimental tests were conducted to study the bed material balance in a cold circulating fluidized bed(CFB)test rig with breeches-legs,during which dynamic curves of air flow rate and bed pressure were obtained under different fluidization parameters.Based on theoretical model of parallel flow,the overturn condition in breeches-legs CFB was predicted,while the effects of control system simulated.Results show that the breeches-legs furnace will work in the self-balance zone if the fluidization air rate exceeds the critical value,in which case,the instantaneous deviation of air flow rate and bed pressure at both sides of the furnace will redress with one another and the bed material in both legs will be in dynamic balance.Bed inventory overturn occurs under the condition the total fluidization air rate being less than the critical data. The critical air flow rate decreases with rising static bed height.The method by adjusting valve opening to control the bed inventory overturn has its limitations.The most important way to control bed inventory overturn is to make the breeches-legs system operate in a self-balance state.
引文
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[11]孙纪宁,王哲,杨志伟,等.裤衩腿循环流化床流动特性及翻床机理的研究[J].动力工程学报,2010,30(5):336-341.SUN Jining,WANG Zhe,YANG Zhiwei,et al.Flowing features and mechanism of bed overturn in circulating fluidized bed with breeches-legs[J].Journal of Chinese Society of Power Engineering,2010,30(5):336-341.
[12]WANG Z,SUN J,YANG Z,et al.Bed-inventory overturn mechanism for pant-leg circulating fluidized bed boilers[J].Powder Technology,2011,214(3):469-476.
[13]周星龙,程乐鸣,张俊春,等.六回路循环流化床颗粒浓度及循环流率试验研究[J].中国电机工程学报,2012,32(5):9-14.ZHOU Xinglong,CHENG Leming,ZHANG Junchun,et al.Experiment study on solids suspension density and solids circulating rate in a CFB with six circulating loops[J].Proceedings of the CSEE,2012,32(5):9-14.
[2]ENAULT C.Fluidized bed boiler furnace comprising two hearths separated by an inside leg area:United States,7152537B2[P].2006-12-26.
[3]孙剑.大型循环流化床锅炉燃烧系统特性与建模研究[D].北京:华北电力大学,2010.
[4]吴玉平,周嗣林,蒋茂庆.300MW循环流化床锅炉翻床现象及处理方法[J].热力发电,2007,36(8):55-57.WU Yuping,ZHOU Silin,JIANG Maoqing.Bed-overturn phenomenon of underpants leg in 300 MW CFB boiler and remedial method thereof[J].Thermal Power Generation,2007,36(8):55-57.
[5]陈驰东.双支腿结构CFB锅炉长期低负荷运行的危险点分析及对策[J].浙江电力,2011,30(5):39-41,57.CHEN Chidong.Analysis and countermeasures of dangerous points for long-term operation of double supporting leg CFB boiler under low load[J].Zhejiang Electric Power,2011,30(5):39-41,57.
[6]赵凯,李前宇,米子德.双支腿循环流化床锅炉的燃烧调整[J].华北电力技术,2007(7):22-25,39.ZHAO Kai,LI Qianyu,MI Zide.Combustion adjustment of double dipleg CFB boiler[J].North China Electric Power,2007(7):22-25,39.
[7]李金晶,胡南,姚宣,等.裤衩腿型循环流化床炉膛的翻床试验[J].中国矿业大学学报,2011,40(1):54-59.LI Jinjing,HU Nan,YAO Xuan,et al.Experimental study of the bed inventory overturn in pant-legs furnace of CFB boiler[J].Journal of China University of Mining&Technology,2011,40(1):54-59.
[8]LI J,ZHANG H,YANG H,et al.The mechanism of lateral solid transfer in a CFB riser with pant-leg structure[J].Energy&Fuels,2010,24(4):2628-2633.
[9]李金晶,李燕,刘树清,等.裤衩腿结构循环流化床锅炉床料不平衡现象的数值模拟[J].动力工程,2008,28(1):28-32.LI Jinjing,LI Yan,LIU Shuqing,et al.Numerical simulation of the bed material unbalance between the breeches-legs in a circulating fluidized bed boiler[J].Journal of Power Engineering,2008,28(1):28-32.
[10]杨志伟,王哲,李政,等.裤衩型循环流化床动态数学模型研究[J].动力工程学报,2010,30(11):820-826.YANG Zhiwei,WANG Zhe,LI Zheng,et al.Dynamic mathematic modeling study on circulating fluidized bed with breeches-legs[J].Journal of Chinese Society of Power Engineering,2010,30(11):820-826.
[11]孙纪宁,王哲,杨志伟,等.裤衩腿循环流化床流动特性及翻床机理的研究[J].动力工程学报,2010,30(5):336-341.SUN Jining,WANG Zhe,YANG Zhiwei,et al.Flowing features and mechanism of bed overturn in circulating fluidized bed with breeches-legs[J].Journal of Chinese Society of Power Engineering,2010,30(5):336-341.
[12]WANG Z,SUN J,YANG Z,et al.Bed-inventory overturn mechanism for pant-leg circulating fluidized bed boilers[J].Powder Technology,2011,214(3):469-476.
[13]周星龙,程乐鸣,张俊春,等.六回路循环流化床颗粒浓度及循环流率试验研究[J].中国电机工程学报,2012,32(5):9-14.ZHOU Xinglong,CHENG Leming,ZHANG Junchun,et al.Experiment study on solids suspension density and solids circulating rate in a CFB with six circulating loops[J].Proceedings of the CSEE,2012,32(5):9-14.