【作者】 钟年丙；

【导师】 赵明富；

【作者基本信息】 重庆理工大学 ， 测试计量技术及仪器， 2010， 硕士

【摘要】 生物膜滴滤塔反应器是一个含生化反应的多元多相流、传热传质的复杂体系,流体的多相流动和传输特性又与多孔填料塔内的生化反应特性密切相关。总结国内外相关的理论和实验方面的研究工作可知:生物膜滴滤塔反应器可以动态控制、并能够影响有机废水降解效率的热物理参数包括:系统温度场、有机废水的浓度场和速度场、气相的浓度场和速度场、反应器填料段的压力场等。这些参数具有复杂性、空间分布性、时间动态性,并直接或间接地影响着有机废水中的有机质在生物膜中的扩散速度场、浓度场乃至生物膜厚度等,从而影响生物膜对有机废水的降解效率。正是由于反应器中生化反应过程的这些复杂性和不确定性,导致了过程机理研究与过程优化控制的困难。文章提出采用“分布式光纤Bragg光栅(FBG)”技术对反应器内温度场分布进行实验研究,同时建立了能够完整描述反应器内温度场分布的数学模型,研究了温度和压力二参量对FBG的交叉敏感特性。主要研究成果如下:①设计并搭建了处理有机废水的实验装置,根据反应器的几何特征和处理对象设计并制作了液体分布器、液体收集器。分析了影响反应器降解效率的因素。②设计并制作了FBG温度传感单元、FBG温度传感阵列,研究了传感单元和传感阵列的温度分辨率、测量误差以及各传感单元Bragg中心波长漂移量与温度之间满足的函数关系。实验结果表明:FBG温度传感单元以及传感阵列的温度分辨率为0.10℃,误差为±0.20℃。研究了温度和压强二参量对FBG交叉敏感特性,给出相应的数学模型和仿真结果。仿真结果表明:当ΔT和ΔP的值分别达到90℃和90MPa时,交叉敏感项的值将达到1pm。③根据热力学参数、气-液-固-生物相参数以及滴滤塔结构参数等,以细胞代谢产热模型、非牛顿流体在毛细管内的渗流模型、毛细管展开微平面上对流传热的等效模型,建立了一个完整的用于描述反应器内温度场分布、压力场分布的数学模型。深入研究了反应器内温度分布与降解效率之间的函数关系。④采用FBG温度传感阵列系统,对生物膜反应器在挂膜启动前、挂膜启动初期、挂膜启动稳定后的温度场分布进行了实验研究。实验结果表明:由挂膜启动初到挂膜启动稳定后(120h～360h),填料段径向温差由0.80℃增加到1.38℃,轴向温差由2.08℃增加到3.04℃。在液相流变速循环条下,填料段上部温度随液相流流速的增加变化明显,最后趋于流体进口温度;填料床下部温度随循环液流速的增大而升高,当液体流速达到45L/h时,填料床下部温度超过上部温度。更多还原

【Abstract】 Trickling biofilter reactor is an extremely complex system which is composed of biochemical reactions, multiphase fluid flow, heat and mass transfer. And fluidic multiphase flow and transmission property are closely associated with the characteristics of biochemical reaction in the packing column. The paper has researched the literatures including domestic and international theories and experiments, and concluded that the trickling biofilter can be dynamically controlled and the treatment efficiency of the trickling biofilter will be affected by the thermophysical parameters including the system temperature field, concentration and velocity field of organic wastewater, gas velocity and concentration field and pressure field in the reactor etc. these parameters are of complexity, spatial distribution and dynamic characteristic of the time. Simultaneously, the organic matter diffusion comprising velocity field, density field even the biofilm thickness in the biofilm has been directly or indirectly affected by the parameters. Eventually, the affection has given rise to the degradation efficiency of the trickling biofilter for treating the organic wastewater. The biochemical reactions process is of considerable complexity and uncertainty in the biofilm reactor, which increases the difficulty to study the mechanism and optimal control process. The temperature field of reactor has been researched by the technology of distributed fiber Bragg grating (DFBG), a theoretic model has been established for describing temperature distribution of the reactor, and the cross-sensitivity characteristic of fiber Bragg grating (FBG) on temperature and pressure was studied in the paper. The main results are as follows.①The experimental device for treating organic wastewater, and the liquid distributor and collector which accorded to the geometric characteristics of the reactor and processing object, were designed and constructed. Meanwhile, there were analyses on the degradation efficiency impact factors of the reactor.②FBG temperature sensor unit and array were designed and built. The temperature resolution, measurement error, and the functional relationship between the Bragg center wavelength drift and the temperature were researched for the sensor unit and array. The experimental results show that the resolution was 0.10℃, and measurement error was 0.20℃of the FBG temperature sensing unit and array. Besides concentrating on the cross-sensitivity characteristic of temperature and pressure for FBG, the mathematical model and simulation results were achieved. The simulation results show that the value of cross-sensitive items reached 1pm when the temperature and pressure respectively changed to 90℃and 90MPa.③According to the parameters involving thermodynamic parameters, gas-liquid- solid-biology multiphase flow parameters and structure parameters of the biomembrane reactor etc, the mathematical models of temperature and pressure distribution in the reactor were figured out which based on the models including the metabolic heat model of cell, seepage flow model of non-newtonian fluid in the capillary, and convection heat transfer equivalent model on expanding micro-plane of the capillary. Also, it focused particularly on the research of the theoretical modle between temperature distribution and degradation efficiency of the reactor.④There were experimental studies on the temperature distribution of biofilm reactor including pre-start-up, early-start-up and after stable-start-up by adopting the system of FBG temperature sensor array. The results reveal that the radial temperature difference was from 0.80℃to 1.38℃and axial temperature difference from 2.08℃to 3.04℃when the start-up was from initial to stable (120h～360h) in the packing section. While the liquid fluid was with variable velocity, the upper part temperature of the packing section changed significantly with the increase of the liquid flow rate, finally, it tended to fluid inlet temperature. The lower part temperature rised accordingly with the increase of the liquid flow rate, and it was higher than that of the upper part when the liquid flow rate reached 45L/h.更多还原