【作者】 朱寿礼；

【导师】 廖强；

【作者基本信息】 重庆大学 ， 工程热物理， 2004， 硕士

【摘要】 全球工业化进程的加快而带来的各类环境污染问题逐渐引起人们的广泛重视。低浓度有机废气回收利用价值低,用传统的物理和化学方法处理,不仅难度高投资大,而且效果不好。微生物法处理低浓度有机废气以其净化效果好,操作稳定,能耗小,投资少,运行费用低,无二次污染等优点成为世界工业废气净化研究的前沿热点课题之一。在国外,已有相当数量的实际工业装置投入运行,而在我国只见到少数研究报道。本文对生物膜滴滤塔内的两相流体流动和降解特性进行理论研究:(1)将生物膜滴滤塔内多孔填料床通道简化为平行平板通道,建立了一个稳态的生物膜滴滤塔净化废气的平行平板通道理论模型。该模型首先运用两相流理论获得了通道内液膜厚度,然后通过污染物在气相、液相的质量组分方程,结合生物膜内的传质与不考虑氧气限制的生化反应动力学方程,获得了污染物在液相和生物膜中浓度分布的近似分析解。(2)在平行平板通道理论模型的基础上,首次将多相混合模型运用于具有气-液两相流动、有机污染物扩散、生物膜内发生生化反应的多孔填料滴滤塔内,建立了生物膜滴滤塔内含有生化反应的多相混合模型。模型理论预测值与生物膜滴滤塔净化低浓度甲苯废气的实验结果基本吻合。(3)在生物膜滴滤塔内含有生化反应的多相混合模型的基础上,结合代谢产热理论,首次建立了生物膜滴滤塔代谢产热模型。平行平板理论模型和多相混合模型的计算结果均表明:(1)随着气、液流量的增大,生物膜滴滤塔降解甲苯的净化效率均降低。(2)填料床孔隙率一定时,随着填料比表面积的增大,生物膜滴滤塔降解甲苯的净化效率增大,并且填料比表面积越大,对净化效率的影响越小。(3)随着填料床高度的增加,生物膜滴滤塔净化效率增加。(4)随着甲苯进口气相浓度的增大,生物膜滴滤塔的净化效率增大,但其增大的幅度不大。生物膜滴滤塔代谢产热模型的计算结果表明:(1)随着甲苯进口浓度的增大,滴滤塔进出口温差增大。(2)随着气体流量的增大,滴滤塔的进出口温差增大。(3)随着液体流量的增大,滴滤塔的进出口温差减小。(4)填料床孔隙率一定时,随着填料比表面面积的增大,滴滤塔的进出口温差增大。(5)填料比表面积一定时,随着填料床孔隙率的增大,滴滤塔的进出口温差减小。(6)随着填料床高度的增大,滴滤塔的进出口温差增大。更多还原

【Abstract】 Environmental pollution resulted from the progress of global industrialization has attracted people’s great attention. The recovery of low concentration VOC waste gas is valueless and its treatment is very difficult and expensive for traditional physical and chemical treatment technologies. The biological treatment technology of low concentration VOC waste gas has been a hotspot problem in the world,?which has a lot of advantages, such as high purification efficiency, easy operation, low energy consumption, low charge of investment and run, and no secondary pollution etc. At present, many practical equipment have been applied in the control of atmosphere pollution, while there is only a few reports in our country. This paper, author has studied the two phases flow and the degradation characteristic of trickling biofilter: (1) A parallel plat plates theoretical model for purification of low concentration VOC waste gas has been established with simplifying the porous packed material in the trickling biofilter to a parallel plat plates passage covered with biofilm. In the model the liquid film thickness in the passage has been obtained at first using two phase flow theory; then, similar analysis solution of concentration distribution of the pollutant in liquid phase and biofilm has been obtained through mass component equation of pollutant in gas-liquid phases combined with the biochemical kinetic equation of mass transfer in biofilm and dismission of oxygen limited. (2) Based on the parallel plat passage theoretical model, a multiphase mixture model in trickling biofilter with biochemical reaction has been first established applying a multiphase mixture model in porous packed material trickling biofilter with gas-liquid flow, pollutant diffusion and biochemical reaction in biofilm. The predicted value of model theory coincided basically with the experimental result of the waste gas toluene of low concentration in the trickling biofilter. (3) The metabolized heat model in trickling biofilter has been established first combined with a multiphase mixture model in trickling biofilter with biochemical reaction and theory of metabolism.The results of parallel plat plates model and the multiphase mixture model both show that: (1) the purification efficiency of trickling biofilter reduces as the gas or liquid flux increasing. (2) the purification efficiency of trickling biofilter increases as the special surface area of packed material increasing at a constant porosity of packed <WP=7>bed. Furthermore, when the special surface area of packed material is bigger, the effect of it on purification efficiency is less. (3)the purification efficiency of trickling biofilter increases as the height of packed bed increasing. (4) the purification efficiency of trickling biofilter increases as toluene inlet concentration increasing, but the increase in purification efficiency is small. The results of metabolized heat model in trickling biofilter show that: (1) Temperature difference between inlet and outlet of trickling biofilter increases as toluene inlet concentration increasing. (2) Temperature difference between inlet and outlet increases as gas flux increasing. (3) Temperature difference between inlet and outlet reduces as liquid flux increasing. (4) Temperature difference between inlet and outlet increases as the special surface area of packed material increasing at a constant porosity of packed bed. (5) Temperature difference between inlet and outlet reduces as porosity of packed bed increasing at a constant. special surface area of packed material. (6) Temperature difference between inlet and outlet increases as the height of packed bed increasing.更多还原