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

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.