电厂送粉系统煤粉浓度和速度的在线测量技术研究  

Study of the Technology of On-line Pulverized-coal Concentration and Velocity Measurement for Power Plant Pulverized-coal Conveyance Systems

作　　者：孙猛[1] 刘石[2] 雷兢[1] 李志宏[2] 

机构地区：[1]中国科学院工程热物理研究所,北京100080 [2]华北电力大学电站设备状态监与控制教育部重点实验室,北京102206

出　　处：《热能动力工程》2009年第2期211-215,共5页Journal of Engineering for Thermal Energy and Power

基　　金：国家自然科学基金资助项目(60672151,50736002)

摘　　要：锅炉燃烧过程中,准确测量各风管中的煤粉浓度并指导调节对锅炉的安全、经济运行非常重要。采用电容层析成像技术(ECT),对常温下稀疏气力输送的固体浓度及速度进行了测试研究。为克服电容传感器敏感场的不均匀性对成像造成的影响,实验系统中装置了一旋风分离装置,通过旋风分离作用将固体颗粒主要集中在壁面区域,传感器电极布置在分离器直管上。利用单层8电极电容传感器通过预迭代的图像重建算法获得浓度分布。通过分析旋风分离装置内上下游流动的概率和频谱特性,验证了其流动满足电容相关测试要求,通过测量上下两层电极电容相关信号获得轴向速度,切向速度由同一层传感器相邻电极对的电容相关信号获得。通过对管道截面体积分数、轴向速度及切向速度的测量与比较分析,证明该方法可获得可靠的测量结果。The accurate measurement of pulverized coal concentration in each air pipe and its guidance role for regulation during a combustion process are very important to the safe and cost-effective operation of a boiler.By using capacitance tomography,tested and studied were the concentration and velocity of solids conveyed by a dilute-phase pneumatic force at a normal temperature.To overcome the impact of the nonuniformity of the sensitive field of a capacitance sensor on image formation,a cyclone separator was set up in the test system.The role of the cyclone separator is to concentrate the solid particles mainly in the wall-surface zone with the electrodes of the sensor being located on the straight pipe of the separator.The concentration distribution was obtained by using a single-layer 8-pole capacitance sensor and adopting a pre-iterative image reconstruction algorithm.An analysis of the probability and frequency spectrum characteristics of flows at the upstream and downstream of the cyclone separator has verified that the flows can meet relevant requirements for capacitance measurement.In this connection,the axial velocity was obtained by measuring relevant capacitance signals from the poles in the upper and lower layers,and the tangential velocity was ascertained by measuring the relevant capacitance signals from a pair of adjacent poles in the same layer of the sensor.The measurement and contrast analysis of the volume fraction,axial and tangential velocity in the pipe section have proven that the method under discussion can ensure reliable measurement results.

关 键 词：电容层析成像 煤粉浓度 体积分数 速度测量 气固两相流 

分 类 号：TK224.1[动力工程及工程热物理—动力机械及工程]