多管环流反应器的气含率研究

提出了一种新型结构的多管式环流反应器,对于空气－水体系,在每个上升管气速为０～０．１６ｍ／ｓ和管径比Ｄｄ／Ｄｒ＝０．３～１．０范围内,研究了两个上升管气速及不同管径比时上升管气含率的变化规律,同时研究了分离箱中静液高及分离箱结构参数与下降管气含率之间的关系。提出了在鼓泡流区域内上升管气含率模型方程：Ｅ１＝αＵｂｇ１－ｃＵｇ３     

Performance of an integrated reactor with airlift loop and sedimentation for municipal wastewater treatment: A 150 m3/d pilot case study

A newly developed bio-reactor design for municipal sewage treatment was evaluated on a pilot scale (150 m³/d). The reactor system included both anaerobic/anoxic and aerobic treatment stages with external/internal airlift circulation loops integrated with a central sedimentation chamber. The design was conceived to enhance the removal of organic compounds and nutrients (phosphorus and nitrogen) within a smaller footprint than existing treatment processes. The downcomer of the internal circulation loop is integrated with the sedimentation tank facilitating high efficiency solid-liquid separation in a compact configuration. The external/internal airlift circulation stages increase the potential for bio-reactivity, while reducing energy consumption for process flows. Overall, the integrated configuration reduces the footprint required compared to conventional systems with equivalent hydraulic loads, ie, hydraulic retention time of ~12.8 hours with a hydraulic loading area of 10.3 m³/d/m². The trial run data indicated removal efficiencies for COD, phosphorous, ammonia, and total nitrogen of 94.5%, 94.5%, 96.8%, and 78.6% respectively. Moreover, the treatment system also demonstrated a robust capacity to handle a wide range of COD influent concentrations (ie, ~ 120-860 mg/L).     

外环流气升陶瓷膜精制盐水研究

采用气升式陶瓷膜过滤工艺进行盐水精制,研究了曝气量、跨膜压差和料液固含量对膜通量的影响,并计算了过滤阻力及表观能耗.实验结果表明,跨膜压差为60 kPa,曝气量从200 L/h增加到500 L/h时,膜通量从200 L/(m2.h)增加到360 L/(m2.h),提高了80%;进一步提高曝气量,膜通量的增幅不大.曝气量为500 L/h时,膜通量随跨膜压差的增大而线性增加.曝气条件下,固含量在0~25 g/L范围内,随着固含量增大,膜通量略有下降,降幅小于10%.计算结果表明,曝气过程能够有效降低膜过滤阻力,基本消除浓差极化的影响;与错流过滤相比,通过气液两相流对膜过程的强化作用,气升过程能使表观能耗显著降低.     

再分布板对环隙气升式反应器内多相流动的影响

为了考察环流反应器放大过程中再分布板对其内部多相流动的影响,采用欧拉双流体模刑模拟了再分布板小同高度的布置对环流反应器内气含率,循环液速,固体颗粒分布等参数的影响,并与部分冷模实验结果进行了比较,两者结果一致结果表明,再分布板高度的增加会使气升反应}州为气含率旱现先增后减的趋势,并导致导流管内的固含率上升。此外,小同高度的再分布板对环流反器内整体气含率及循环液速的影响小大结合CFD模拟和实验结果,优化了环流反应器内再分布板的设计,从而为实现强化环隙气升式环流反应器内多相流动、传递、反应等过程提供了一定的指导意义     

蛋白核小球藻的培养及应用研究

选用密闭气升式反应器进行自养培养蛋白核小球藻,通过单因素优化获得碳源二氧化碳的通气量2%,氮源硝酸钠为10 g/L;通过对蛋白核小球藻培养基的均匀设计,获得了适宜的培养基组成：磷酸氢二钾0.6 g/L,硫酸镁0.2 g/L,硝酸钠11 g/L,硫酸钾0.8 g/L,柠檬酸铁胺0.006 g/L,氯化钙0.05 g/L,维生素B10.11 g/L,EDTANa20.01 g/L,钨酸钠0.08×10–3 g/L,氯化镍0.02×10–3 g/L;实验采用中间白光四周彩光的合适光源,用除氧剂使氧气维持在20%左右,获得了8.648 g/L的干菌体。经分析,蛋白核小球藻蛋白质含量高达58 g/100 g,同时含有丰富的氨基酸和矿物质元素。用蛋白核小球藻替代艾草粉,制作出了蛋白核小球藻青团。     

高长径比三相内环流反应器中细颗粒相含率和循环液速的分布研究

在高径比为22的三相内环流反应器中,在常温常压下以空气-水-石英砂为物系,研究了在不同粒径下上升区固含率、下降区固含率和上升区循环液速随表观气速的变化规律和不同粒径下轴向固含率的分布情况,以及在固体体积分数不同的条件下,平均气含率和上升区气含率随表观气速的变化情况。结果表明:当粒径(ds)≤0.3 mm时,上升区固含率随表观气速的增加呈平缓变化趋势,下降区固含率随表观气速的增加而增加;当0.3 mm相似文献   

作业工况及喷射方式对气举输出的影响

基于流体力学理论,从静力学角度,进行了气举管内压力分析,研究了不同作业工况及喷射方式对气举输出的影响,分析了气举输出特性随吸口下降深度的变化规律。结果表明,气举垂直作业存在固相与液相流量变化趋势相反的平衡段,吸口底部漏斗状坑径变大、局部流体加速、紊流增多,有利于固体颗粒的提升; 对称喷射方式固相空隙率更高,提升固体颗粒性能更好,而非对称喷射方式明显增强了气举吸口附近的局部扰动,更有利于采矿作业过程中液体提升。     

低高径比外循环气升式生物反应器带渣发酵生产有效霉素

Fermentation experiments to produce validamycins from crude substrates by Streptoniyces hygroscopi-cus were carried out in an external-loop airlift bioreactor (0.0115 m3 ) with a low ratio of height to diameter of the riser of 2.9 and a ratio of riser to downcomer diameter of 6.6. The influences of gas flow rate and liquid volume on fermentation of validamycins were investigated. Comparisons of validamycin fermentation were made among the external-loop airlift bioreactor, a mechanically stirred tank bioreactor (0.010m3 ) and shaking flasks. Under the same operation conditions including fermentation medium composition, inoculum ratio and culture temperature, the fermentation time in the external-loop airlift bioreactor (45 h) was shorter than that in the shaking flasks (100 h) and the same as that in the mechanically stirred tank bioreactor. After a total fermentation time of 45 h under optimized operation conditions, average validamycin concentration obtained in the external-loop airlift bioreactor was     

气升式环流反应器光催化处理难降解有机污染物试验研究

利用气升式环流光催化反应器对难生化降解活性艳红X-3B的光催化降解性能进行了研究。系统分析了底物初始浓度、溶液初始pH、催化剂投加量、反应温度、曝气量以及紫外光辐射强度等因素对底物光催化降解反应的影响。结果表明,在反应溶液pH为4~10、催化剂质量分数为0.5 g/L、曝气量为2.5 m³/h、活性艳红X-3B初始浓度为50 mg/L的条件下,活性艳红X-3B光催化3 h后的降解率可达到85%以上。反应动力学研究结果表明,活性艳红X-3B光催化降解可用Langmuir-Hinshelwood 模型描述。建立了以反应时间、底物初始浓度、紫外光强度和曝气量为变量预测体系对活性艳红X-3B的光催化降解效果经验模型,预测值与试验值间的决定系数为0.958,可为后续放大试验提供借鉴。     

Modelling of the fluid dynamic processes in a high‐recirculation airlift reactor

This paper describes the creation of two models of the steady‐state fluid dynamic processes occurring in a high‐recirculation airlift reactor. The new models were created to provide information to assist in the design of a reactor, in particular considering the selection of parameters to adjust in order to achieve a steady state solution. The modelling of two‐phase flow of air and water in small‐scale airlift bioreactors is considered. This modelling was applied to the high‐recirculation airlift reactor process. New computer simulations were created and tests performed to evaluate the new models. The results of this evaluation are presented. The evaluation showed that variation of the superficial gas velocity or the simultaneous variation of the downcomer and riser diameters could be used to produce a steady‐state design solution. Copyright © 2001 John Wiley & Sons, Ltd.