研究流化床内废物焚烧过程中重金属挥发特性的反模型化方法

用反模型化方法研究在流化床焚烧模拟废物过程中重金属 (HM)释放的动力学特性 .该方法包含了出口气体中的HM浓度变化规律 (实验数据 )和一个反应器尺度的模型 .在实验尺度的流化床焚烧反应器内对掺混了金属的模拟废物进行了热处理 ,对一种从废物中得到的并掺混有重金属 (Cd ,Pb和Zn)的物质进行了焚烧处理 ,用来模拟城市固体废弃物焚烧过程中的HM释放过程 .在反应器的气体出口安装了在线分析系统 ,该在线分析系统通过用ICP OES连续测量出口气体中的HM相对浓度变化规律能够全面的跟踪金属的挥发过程 .此外 ,还运用并发展了鼓泡床模型 ,应用此模型根据出口气体中的HM浓度和时间关系计算出HM挥发率 .利用反模型化方法可以通过在线分析的结果确定出颗粒尺寸的HM挥发动力学特性 .

An inverse method study of heavy metal vaporization kinetics from fluidized wastes

The objective of this study was to propose a method to determine the kinetics of heavy metal (HM) release from model wastes in fluidized bed. This method was an inverse method, which involves only the HM concentration evolution in the exhaust gases (experimental data), and a model developed at the reactor scale. The thermal treatment of metal-spiked model wastes was performed in a lab-scale fluidized bed incinerator. A complex matrix, derived from real waste, was spiked with heavy metals (Cd, Pb or Zn) and was burned in order to simulate the metal release during municipal solid waste incineration. An on-line analysis system was set at the gas outlet of the reactor, it enabled to track successfully the metal vaporization process: the relative HM concentration variation in exhaust gases was measured continuously by ICP-OES. A bubbling bed model, which calculates the HM vaporization rate from its concentration time profile in the outlet gas, was developed and validated. The inverse method is capable of identifying the HM vaporization kinetics at the particle level only from the on-line diagnostic results and using the model, and this method can be applied for different waste.