【作者】 王立章；

【导师】 赵跃民；

【作者基本信息】 中国矿业大学 ， 环境工程， 2009， 博士

【摘要】 填充床电化学技术是有效治理高盐分、高有机物浓度和高色度化工废水的可行途径;然而,反映床层流固耦合特征和有效预测有机污染物浓度变化规律模型的匮乏成为制约该工艺推广应用的主要瓶颈。本研究即以填充床电化学反应器为研究对象,着重描述动态运转条件下床层各点污染物浓度、电势、电流及反应速率的分布规律,以期为反应器工程设计提供合理的理论依据;同时,基于理论分析、数学建模、实验室实验和工程验证等手段主要获得如下成果:(1)提出了“复相控制”的新概念用于描述阳极处于扩散控制而粒子电极处于反应控制状态的过渡反应步骤,完善了填充床电化学反应器氧化有机物的反应历程。(2)基于法拉第定律,得出了适合于描述填充床电化学反应器电流效率的表达式;理论数值与实验数据具有较高的相关性。(3)基于床层反应控制、复相控制和扩散控制状态的综合表征,提出了电化学反应器氧化有机物的“阶段反应理论”。该理论利用极限电流密度与操作电流密度之间的关系界定有机物氧化反应控制步骤,探究各种控制步骤下的动力学特征,揭示有机物反应进程与操作条件、反应介质物化属性以及反应器构型之间的定量函数关系,为床层各点有机物浓度的分布规律预测提供了完整、充分而精确的理论依据。(4)建立了反应器通用能量模型。能够根据与废水性质相联系的特征参数K1、K2的数值得出最佳极板间距;也能够用于描述反应控制、复相控制以及扩散控制状态下的有机物氧化动力学行为。该模型结合“阶段反应理论”能够精确指导实际工程设计。(5)引入Poisson方程并结合“阶段反应理论”能够完整的对床层各点电势进行有效预测;实际工业废水的小试实验数据表明,理论数据与实测数值具有较高的相关性,床层电势、超电势、电流和反应速率具有可预知性;该结论可用于床层反应参数的优化与运营管理。(6)采用淀粉废水、助剂废水、DSD酸还原和氧化工段废水为实验对象,所得数据能够在床层浓度分布规律、电流效率和能耗方面与“阶段反应理论”预测数据一致;同时,应用“阶段反应理论”和通用能量模型用于甘氨酸生产废水处理设备的工程放大设计取得了与理论预测大致相同的出水效果。这均表明,本研究所建立的模式可作为填充床电化学反应器设计体系建立的基础。通过本研究不仅仅验证了填充床电化学反应器处理废水的广谱性,它能够作为常规废水的预处理措施提高可生化性,亦能作为高盐废水的终处理措施;结果表明,本工艺用于高盐废水处理更具竞争性。同时,理论的建立也为该工艺的普及、精确设计、操作管理、优化运行等提供了极大可能性。更多还原

【Abstract】 Packed bed electrochemical technology is a feasible and effective approach for high concentration organic wastewater treatment with large colority and salinity. However, lack of the kinetics for the coupling of electrodes, fillings and concentration prediction of organics in the bed electrode hinders the transfer of this technique. Therefore, it is necessary for thorough research of the process. At the same time, the achievement obtained through varied means such as theoretical analysis, modelling, laboratory and pilot-scale experiment are as follows:(1) the concept of“multiphase control”was proposed for description of the transition of reaction and diffusion controlled processes, which is a complete supplement for the reaction theory based on sufficient analysis of current researches.(2) a new equation, which is accordance to the experimental data, was obtained for the calculation of current efficiency in packed bed electrochemical reactor (PBER) on the basis of Faraday’s law.(3) a“step-reaction kinetics”, which is related to the charactristics of different reaction stages, was achieved through the determination of reaction, multiphase and diffision controlled processes by the relation between limiting current density and operating current density. The new theory could be employed for the quantized description of the relevance of the organics oxidation and operation conditions, physi-chemical behaviors of solution and configuration of the reactor. Meanwhile, the integrated, sufficient and accurate prediction of the concentration distribution of organic matters in the bed electrode is acquired using this theory.(4) a global energy model was established through the application of laws of the conservation of energy, momentum and electron. The values of characteristic parameters, K1 and K2, which are related to the essence of organics in wastewater, could be obtained when linearized the complex expression of energy equation. Simultaneously, the parameters could be employed for the optimization of inter-electrode distance and the overall kinetic behaviors under reaction, multiphase and diffusion controlled phases also could be described by this model. The accurate design and operation are acquired by the introduction of global energy model and“step-reaction kinetics”through the lab-scale experiments.(5) an effective and precise prediction of potential distribution in bed electrode could be conducted using“step-reaction kinetics”coupled with Poisson’s equation. The results for starch wastewater, auxiliary wastewater, DSD acid wastewater from reduction and oxidation processes treatment revealed that the experiments was consistent with the theoretical ones and the potential, over-potential, current and reaction velocity of the bed electrode during the oxidation could be estimated by the kinetics proposed in this research. All in all, the optimization of the reaction and design parameters and management of the technology are easily achieved by the integrated theory.(6) the experimental results for the four kinds of different industrial wastewater treatment were in good agreement to the step-reaction kinetics on the prediction of concentration distribution, current efficiency and energy consumption of the bed electrode. Moreover, the successful fitting between these theories and experiments in glycine wastewater treatment using the engineering scale-up bed electrode indicates that the kinetics proposed in this study could be used for the accurate design of the PBER.The research demostrates that the PBER is wide-adaptable in environmental protection engineerings: it not only can be employed as a kind of pretreatment measure to improve the biodegradability of regular wastewater, but also for the final handle way of high salinated wastewater. However, the competitive advantages are noticeable in the application of solution with high salinity. Concomitantly, the development and improvement of kinetics for the PBER provide some significant possibility on its technical spread, rational design and optimal operation.更多还原