改进型外循环厌氧反应器处理蓝藻启动与颗粒污泥特征

采用自行改进设计的外循环厌氧反应器处理太湖蓝藻,研究其快速启动过程中运行效能以及颗粒污泥微生物特性。实验结果表明:反应器采用“投加接种污泥、阶梯提高负荷连续运行、间歇搅拌”的启动运行方式,可以在35 d左右实现蓝藻成功处理。启动成功时,反应器对蓝藻化学需氧量(COD)去除率在85%左右,产气率在380 ml·(g COD)^-1左右,藻毒素的去除率达到92%;颗粒污泥中菌群以球菌、丝状菌为主,颗粒污泥内丰富的空穴为物质迁移和微生物降解提供通道。反应器启动成功后颗粒污泥中主要优势产甲烷古菌为Methanosphaera,Methanolinea,Thermogymnomonas,Methanoregula,Methanomethylovorans,Methanosaeta等;颗粒污泥中蛋白酶及辅酶F₄₂₀的活性较强。研究发现间歇搅拌装置及回流系统克服蓝藻在反应器中上浮结壳的弊端,同时加快反应器内传质效果,从而有助于反应器的快速启动。     

农村生活污水处理ABR工艺的启动与污泥微生物特性

通过折流板厌氧反应器(ABR)处理农村生活污水的启动运行,以及高通量测序技术,研究反应器中污泥微生物相关特性。研究结果表明:反应器采用低负荷启动、阶段提高有机负荷方式,可以在60d内实现挂膜完成,反应器对污水中化学需氧量(COD)去除率在66%左右,出水pH值稳定在6.35~7.05;颗粒污泥中主要优势细菌种群有变形杆菌(Proteobacteria)、拟杆菌纲(Bacteroidetes)、绿弯菌纲(Chloroflexi)。运行启动后,在污泥中出现广古菌门(Euryarehaeota)、嗜热丝菌门(Caldiserica)、螺旋菌门(Spirobacteria)。运行稳定后,细菌生物量含量会减少,这表明ABR启动对原始污泥的微生物种类起到显著的选择作用。     

EGSB反应器运行过程中颗粒污泥微生物相解析

本文研究了EGSB反应器运行过程中颗粒污泥的形态,微生物相及优势菌群的分布状况.结果表明,随着运行时间和有机负荷的提高,反应器中颗粒污泥的粒径逐渐增大,且污泥床底部颗粒污泥的粒径大于上部的污泥粒径,呈明显的分层现象.在扫描电镜下观察颗粒污泥的微生物相,运行初期甲烷丝菌属为优势菌群;随着有机负荷的提高,甲烷丝菌逐渐减少,甲烷杆菌占优势;待反应器稳定运行后,菌群类型更加丰富多样,多种产甲烷菌混栖.同时,观察得知EGSB反应器不同高度颗粒污泥的形态和微生物相分布也表现出特有的规律性.     

硬硅钙石对同步培养驯化颗粒污泥去除含铅废水的影响研究

本文对硬硅钙石同步培养颗粒污泥处理含铅废水进行了试验研究,分析了硬硅钙石对反应器的运行、出水指标、微生物、铅的去除率的影响,同时对微生物进行了SEM检测。结果表明,硬硅钙石同步培养污泥不仅保证了反应器的正常运行,而且加快了反应器中污泥颗粒化进程,污泥抗毒性冲击,铅的去除率达到95%以上。     

厌氧流化床生物膜形成及稳定性的研究

在自行设计的厌氧流化床反应器上地厌氧流化床生物膜的形成及其稳定性进行了研究，考察了影响反应器内生物滞留量的因素（接种污泥，温度，ｐＨ，基质特性，有机质负荷）和影响生物膜构成的因素（微生物的品种及性质，生物化学反应，载体，水力特性）简述了生物膜的形成机理。     

EGSB反应器在微氧条件下去除焦化废水中挥发酚

以厌氧和间歇微氧条件为参照,分析EGSB反应器在连续微氧条件下对焦化废水中挥发酚的去除,在反应器运行过程中,进水挥发酚质量浓度在10.09～201.34 mg·L-1之间,微氧反应器有很好的抗冲击负荷能力,挥发酚的去除率保持在98％左右,温度降低后,使微氧反应器挥发酚的去除率由99％降到27％；微量的氧有利于EGSB反应器的稳定运行,反应器能够降解一些在纯厌氧情况下不能去除的难降解物质和有毒物质；颗粒污泥内部的产甲烷菌对于微量氧的加入并不敏感；微氧反应器中颗粒污泥的微生物种群丰富,从外到内微生物分层生长,依次为好氧菌、兼性菌、厌氧菌.     

进水负荷交替变化对好氧污泥颗粒化的促进

在序批式活性污泥法反应器(SBR)中,接种普通絮状污泥,在交替变化的负荷下培养好氧颗粒污泥,研究分析好氧污泥颗粒化的形成过程并检测颗粒污泥形成中污染物的变化规律。结果表明,进水负荷的交替变化可以增强反应器的贫富基质促使颗粒污泥快速形成,污泥颗粒化中胞外聚合物含量呈增加趋势,其中胞外蛋白质对好氧污泥颗粒形成中起到主要作用,而胞外多糖有助于维持好氧颗粒污泥系统运行的稳定性,另外变负荷还可筛选出微生物种类丰富度高的颗粒污泥。经过105 d,反应器内颗粒污泥的粒径多数为1.0~1.25 mm,混合液MLSS的质量浓度为5.512 g/L,SVI为18.50 m L/g左右,对COD、NH4+-N、TN和PO43--P的去除率分别为96.73%、96.67%、86.63%和83.74%左右。     

好氧生物流化床处理抗生素废水的试验研究

采用以新型高分子材料为生物载体的生物流化床工艺处理高浓度的抗生素废水。试验结果表明,该载体挂膜容易,启动快,一个月后载体附着的生物量可达4136mg/L,在载体表观体积为反应器总体积的50%、进水COD容积负荷低于2.5kg/(m3·d)的情况下,COD去除率可达85%以上。该生物流化床对BOD5的去除率平均高达89.21%,与COD的去除率具有同步性。并研究了反应器中悬浮污泥浓度SS和总生物量MLSS在整个实验期间的动态变化,表明稳定运行时SS和总MLSS基本上稳定不变,当系统受到高负荷冲击时,SS降低,总MLSS升高,而且生物活性也大幅度提高,生物膜处在适应期,反应器抗冲击负荷能力增强。     

EGSB反应器在20℃下处理啤酒废水的工艺及微生物学研究

在20℃下连续运行厌氧膨胀颗粒污泥床（EGSB）反应器,对其处理模拟啤酒废水的工艺运行、污泥特性及微生物种群结构进行研究,结果表明：①HRT为18h,经184d的运行,EGSB反应器的有机负荷（以COD计）可达10kg/（m^3．d）,COD去除率为85％以上,去除1kgCOD可产沼气0．58m^3;②随有机负荷逐渐提高,颗粒污泥粒径逐渐增大,沉降性能逐渐提高,但当负荷达到10kg／（m^3·d）时,颗粒污泥平均粒径有变小趋势;与中温厌氧污泥相比,低温污泥的胞外多聚物（ECP）总量有较大增加,其中蛋白质含量增加明显;     

循环流化床厌氧氨氧化反应器脱氮性能研究

对循环流化床上部附加无纺布作填料的固定床复合式厌氧氨氧化反应器的性能进行了研究,通过控制废水的循环量来调节反应器底部微生物颗粒的流化状态,并对反应器内对富集的厌氧氨氧化菌除氮性能进行了研究。结果表明,反应器稳定运行270 d,总氮去除率及亚硝氮去除率分别维持在80%及90%以上;最大氮负荷达到15.2 kg/m3.d-1,相应的最大氮去除速率达9.9 kg/m3.d-1。通过批实验,得到反应器稳定运行期厌氧氨氧化菌比活性为0.3 kg/k.gd-1。出水悬浮物(SS)浓度检测、微生物颗粒粒径分布测试、微生物颗粒的扫描电镜(SEM)观测结果均表明,循环流化床厌氧氨氧化反应器具有较高的生物滞留能力,形成的微生物颗粒具有较佳性能。采用荧光原位测定(FISH)分析结果显示,厌氧氨氧化菌在反应器微生物群落中含量超过70%。     

Fluidized‐bed reactor modeling for polyethylene production

Gas‐phase technology for polyethylene production has been widely used by industries around the world. A good model for the reactor fluid dynamics is essential to properly set the operating conditions of the fluidized‐bed reactor. The fluidized‐bed model developed in this work is based on a steady‐state model, incorporating interactions between separate bubble, emulsion gas phase, and emulsion solid polymer particles. The model is capable not only of computing temperature and concentration gradients for bubble and emulsion phases, calculating polymer particle mean diameter throughout the bed and polyethylene production rate, but also of pinpointing the appearance of hot spots and polymer meltdown. The model differs from conventional well‐mixed fluidized‐bed models by assuming that the particles segregate within the bed according to size and weight differences. The model was validated using literature and patent data, presenting good representation of the behavior of the fluidized‐bed reactor used in ethylene polymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 321–332, 2001     

Particle growth kinetics of calcium fluoride in a fluidized bed reactor

Crystallization process in a fluidized bed reactor to remove fluoride from industrial wastewaters has been studied as a suitable alternative to the chemical precipitation in order to decrease the sludge formation as well as to recover fluoride as synthetic calcium fluoride.In the modeling, design and control of a fluidized bed reactor for water treatment it is necessary to study the particle growth kinetics. Removal of fluoride by crystallization process in a fluidized bed reactor using granular calcite as seed material has been carried out in a laboratory-scale fluidized bed reactor in order to study the particle growth kinetics for modeling, design, control and operation purposes.The main variables have been studied, including superficial velocity (SV, ), particle size of the seed material (L₀, m) and supersaturation (S). It has been developed a growth model based on the aggregation and molecular growth mechanisms. The kinetic model and parameters given by the equation fits well the experimental data for the studied range of variables.     

Comparative study of nitrification performances of immobilized cell fluidized bed reactor and contact oxidation biofilm reactor in treating high strength ammonia wastewater

BACKGROUND: The immobilized cell fluidized bed reactor and contact oxidation biofilm reactor are two common choices for high strength ammonia wastewater treatment, however, comparative study of the nitrification performance of the two reactors has not been thoroughly studied. The nitrification performance of the two bioreactors when treating strong synthetic ammonia wastewater was investigated and compared. RESULTS: Results demonstrated that the immobilized cell fluidized bed reactor had a shorter acclimation period, and possessed several advantages over the contact oxidation biofilm reactor, in the form of complete oxidation of 150–360 mg L^?1 ammonia wastewater in a shorter time, higher ammonia removal rates (from 9.6 to 4.32 × 10² mgN L^?1 d^?1) over the temperature range 8 to 32 °C, irrespective of organic load. In contrast, a large reduction in ammonia removal was found in the contact oxidation biofilm reactor with chemical oxygen demand (COD) load. The immobilized cell fluidized bed reactor exhibited stable and high rates of nitrification in the long term. CONCLUSION: These facts demonstrated that the immobilized cell fluidized bed reactor is a suitable selection for high strength ammonia wastewater treatment. Copyright © 2007 Society of Chemical Industry     

Experimental study of the inverse fluidized bed biofilm reactor

A new apparatus, the inverse fluidized bed biofilm reactor, is described. Introduction of the so called inverse fluidized bed, in which low density particles covered by a biofilm are fluidized by downflow of the liquid, allows control of the biofilm thickness and provides a high oxygen concentration in the reacting liquid. Characteristics of the reactor were studied by carrying out two important biotechnological processes: aerobic wastewater treatment by a mixed bacterial culture, and ferrous iron oxidation by the bacteria Thiobacillus ferrooxidans. The bioreaction rates per unit volume of the reactor were up to 14 times higher than those in the equivalent airlift bioreactor. The structure of the liquid flow was determined by a tracer method.     

Modelling fast pyrolysis of biomass in a fluidized bed reactor

A compartmental one-dimensional model of a fluidized bed pyrolytic converter of biomass is presented. Reference conditions are those of non-catalytic fast pyrolysis of biomass in a shallow fluidized bed with external regeneration of the bed material. The fate of biomass and of the resulting char has been modelled by considering elutriation of biomass and char particles, char attrition as well as bed drain/regeneration. The course of primary and secondary pyrolitic reactions is modelled according to a semi-lumped reaction network using well-established kinetic parameters taken from the literature. A specific focus of the present study is the role of the heterogeneous volatile–char secondary reactions, whose rate has been modelled by borrowing a kinetic expression from the neighbouring area of tar adsorption/decomposition over char. The results of computations highlight the relevance of heterogeneous volatile–char secondary reactions and of the closely associated control of char loading in the bed. The sensitivity of the reactor performance to char elutriation and attrition, to proper management of bed drain/regeneration, and to control of gas phase backmixing is demonstrated. Model results provide useful guidelines for optimal design and control of fluidized bed pyrolyzers and pinpoint future research priorities.     

甲醇制汽油固定流化床试验装置的设计

根据甲醇制汽油反应的工艺要求和影响流化床反应器性能的主要特性参数,设计研制了固定流化床反应器,使其作为前期催化剂实验室研发的一个评价装置,并取得了较佳的效果。     

流化床反应器结块故障的声纹特征提取及监测技术

流化床反应器的物料结块故障不仅影响产品质量,严重的还会影响生产。为了监测流化床反应器的物料结块故障,提出了一种基于压电声波传感器和声纹特征提取的故障监测方法。在流化床外壁粘贴压电陶瓷声波传感器,采用长屏蔽电缆电荷传输和音频采样方式,监测流化床内物料撞击床壁的声波信号。分析了正常颗粒物料和物料结块情况下声波信号的时域波形、功率谱和声纹特征,重点比较了正常信号和故障信号声纹特征的稳定性和可区分度。通过提取声纹特征,运用神经网络模型实现了对物料结块故障的准确监测。用不同位置声波传感器的感测信号验证故障监测模型的结果验证了这种方法具有较高的时空域鲁棒性。用不同信号抽取率对原始信号进行了重采样,对重采样数据分别进行了声纹特征提取、监测模型的训练和检验,结果表明适当降低信号采样率不影响流化床物料结块的监测结果。为流化床物料结块故障监测问题提供了一种新的系统结构和实现方法。     

MoO3/MgO as a catalyst in the oxidative dehydrogenation of n-butane in a two-zone fluidized bed reactor

Butadiene has been produced from butane by oxidative dehydrogenation on a MoO₃/MgO catalyst using a two-zone fluidized bed reactor (TZFBR). The effect of the main TZFBR operating variables was studied, and its performance was compared with that of conventional fluidized beds and fixed bed reactors loaded with the same catalyst. These results have been compared with those obtained on a selective V₂O₅/MgO catalyst.     

流化床电化学反应器研究进展

流化床电化学反应器是一种三维颗粒电极反应器,以其比表面积大、传质速率高而备受关注。就流化床电化学反应器在导电机理、数学模型、结构放大以及应用领域的研究现状和进展进行了综述,阐明了该类反应器开发、设计和模型化方面存在的问题,并提出了研究方向。     

1,2-Dichloroethane production by two-step oxychlorination reactions in a fluidized bed reactor

The reaction characteristics of two-step oxychlorination to produce 1,2-dichloroethane as a feedstock of PVC production were determined in a fluidized bed reactor. The effects of superficial gas velocity and gas composition on the reactivity and fluidization stability have been determined to find the optimum operating conditions in the continuous fluidized bed reactor system. It has been found that the average ethylene conversion is 94% with ethylene dichloride (EDC) selectivity of 97-98%, the average HCl conversion is 97.4%, the solid reactant conversion is 54% and a solid inventory ratio for the optimum reaction conversion is 3.3 in the process.