流化床污泥掺烧过程中磷调控粘结失流与削减重金属排放的研究

Difficulties of both treatment of municipal waste water sludge and control of bed agglomeration can be solved by applying the fluidized bed sludge co-combustion technique. However, phosphorus from sludge would influence not only the controlling efficiency of bed agglomeration/defluidization, but also change the pathway of heavy metals emission. The effects of the intereaction among phosphorus, particle agglomeration, and emission behavior of heavy metals are not clearly understood yet. Therefore, this study aims the effect of phosphorus on bed agglomeration/defluidization induced by Na-based alkalis. Distribution of heavy metals during processes is also in consideration. Experiments are conducted by a laboratory scale fluidized bed incinerator and characterization analysis (XRD, XPS, SEM/EDS). Thermodynamic equilibrium calculation model (HSC Chemistry) is used. All the results are taken as references to modify a defluidization time prediction model under the influence of agglomeration inhibition provided by the addition of sludge into a fluidized bed system. Thus, it can be used to predict the defluidization time in Na-P-HMs environment under various fluidized bed operating conditions. Both experimental results and prediction model in this study can be taken as a scientific reference or an operating experience of sludge co-combustion and controlling of heavy metals emission during fluidized bed thermal treatment processes.

流化床污泥掺烧热处理可以解决污泥处理和控制床料粘结失流的问题，然而污泥中的磷成分可能会同时影响控制粘结失流的效果和改变重金属排放的迁移途径，针对磷、粘结失流作用与重金属控制此三方面的交互影响目前尚未理清。本课题拟采用实验室规模流化床焚烧炉进行污泥掺烧模拟实验，结合特征分析(XRD, XPS, SEM/EDS)和热力平衡计算模式(HSC Chemistry)，探索流化床污泥掺烧过程中磷影响Na基碱金属诱发颗粒粘结的控制行为以及重金属化学反应途径的改变规律；进一步将实验和热力学计算的结果修正基于力平衡的失流时间计算模型，有效预测在不同流化床操作条件下Na-P-HMs三相系统影响掺烧粘结抑制的失流时间，同时解决污泥处理处置过程下流化床焚烧炉中床料粘结失流的严重问题，实现控制和削减重金属排放的目标。这对于污泥进行节能掺烧处理及发展其重金属污染物的削减排放控制提供科学依据。

污泥掺烧进行流化床热处理处置被认为是一种最有效的方式之一，但是此过程中污泥含有的磷元素会对粘结失流特性及重金属形迁移转化行为产生影响。然而，针对磷、粘结失流作用与重金属三者之间交互作用目前相关的报道还很少。为此本项目针对上述问题开展了有关研究如下：（1）利用热重法模拟了磷元素对城市固体废物燃烧特性影响，获得相关的热力学参数；（2）利用马弗炉模拟研究焚烧粘结产物，对粘结体进行特性分析了解重金属迁移转化规律，为研究磷对粘结及重金属排放机理研究提供理论基础；（3）利用热力学平衡计算软件HSC Chemistry 9.0，模拟计算P-Na-HMs-SiO2复杂系统交互作用及其特性元素迁移转化特性，获得磷元素影响粘结元素控制的机理及关键固相反应途径，建立流化床掺烧含磷污泥控制粘结过程的理论。（4）利用实验自制的流化床焚烧炉探讨了不同操作条件下，污泥中的磷元素对粘结失流及其过程中重金属在固相中分布情况；（5）修正了基于典型重金属存在下含磷污泥控制流化床粘结过程中的失流时间预估模型。以本内容为基础，申报小组发表论文11篇，其中SCI 5篇，中文核心论文3篇，会议论文3篇，申请发明专利1个，培养研究生4名。上述成果的获得可以为进一步研究污泥流化床掺烧及其过程中重金属的控制提供理论依据，具有一定的现实意义和科学价值。