基于烟气重金属浓度在线监测的流化床蒸发动力学模型

Kinetic Modeling of Heavy Metals Vaporization Based on On-line Emission Measurement in Flue Gas in a Fluidized Bed

应用改进的电感耦合等离子体发射光谱仪对烟气中重金属的相对浓度进行在线测量,以全面跟踪重金属的释放过程。在烟气重金属浓度实时监测基础上,发展动力学模型来研究重金属蒸发释放的动力学特性。应用矿物质基体氧化铝的实验结果来验证数学模型的有效性,理论模拟值与实验结果吻合较好。结果表明应用模型,将烟气重金属在线分析的实验结果作为输入参数,可用于预测重金属的蒸发率。根据重金属的蒸发率和固体颗粒中重金属浓度的关系得到其蒸发的动力学规律,对于氧化铝得到1级反应动力学规律。

An inductively coupled plasma atomic emission spectrometer was developed to continuously measure the heavy metal concentrations in flue gas to track the metal release process. Kinetic models were developed in transient conditions to study the kinetics of heavy metal vaporization, based on on-line emission measurement of heavy m^tals in flue gas. The models were applied to a mineral porous matrix to validate the method. Experimental data concerning Cd released from an alumina matrix in a fluidized bed are in good agreement with theoretical results. Results indicate that this approach permits to predict the extent of heavy metal vaporization from a mineral porous matrix when on-line emission of heavy metal in flue gas is known. The kinetic law of heavy metal vaporization during fluidized bed thermal treatment was derived and a first order law was fitted for the mineral matrix.