【摘要】 利用实验室自制的流化床,模拟城市固体废物研究温度对流化床粘结失流及重金属污染物在固相分布的影响。同时,利用热力学平衡模型辅证重金属在固相中的存在形态,以及利用扫描电镜鉴定了粘结体微观结构。实验结果表明:当碱金属存在时,温度越高,流化床粘结失流时间越短,粘结现象越明显。未发生粘结失流现象时,有无添加碱金属对重金属在固相中的分布相差不大;而当发生粘结现象时,重金属在粘结体中的浓度急剧上升,这是由于碱金属Na形成的低熔点物质,将重金属氧化物包覆在粘结体内或者重金属与碱金属发生化学反应。随着温度的升高,由于挥发的原因,重金属在固相中浓度降低。研究结果将有利于研究粘结控制的诱发因素,及其过程中重金属的迁移转化规律。更多还原

【Abstract】 This study aimed at the effect of temperature on the distribution of heavy metals in solid-phase during agglomeration/defluidization in a laboratory-scale fluidized bed combustor with the thermodynamic equilibrium model. SEM was also employed to identify the eutectics obtained after the agglomeration/defluidization. The results indicated that Na addition promoted defluidization significantly with higher operating temperature. The distribution of heavy metal concentrations before defluidization didn’t much differ from that with no agglomeration. However,the concentration of heavy metals in solidphase increased greatly after defluidization. The main reason was supposed heavy metals entrapped in bed by reacting with Na formed low-melting-point eutectics or attached by the molten eutectics. Due to evaporation or melting of heavy metals,as the temperature increasing,the heavy metals concentration in bed decreased. The results in this study could provide references for the study of the mechanism of the particle agglomeration/defluidization,the migration and transformation of the heavy metals and the control of pollutants.更多还原