污泥龄对复合式膜生物反应器运行特性的影响

在不同污泥龄(SRT)条件下同时运行5套复合式膜生物反应器(HMBR)处理生活污水,进行实验室小试,研究了SRT对HMBR运行特性的影响。试验结果表明,SRT对有机物和营养物质的去除有重要影响,COD、NH3-N、TN和TP平均去除率最高时对应的SRT分别为30、20、30、20 d。此外,过长和过短的SRT均会加剧膜污染,最佳SRT为30 d,对应的膜组件运行周期为117 d。     

拟除虫菊酯生产废水膜生物工艺处理试验研究

通过膜生物反应器处理拟除虫菊酯生产废水的试验研究,论述了膜生物反应器用于处理该废水的可行性和具体工艺条件,为今后废水处理工程改造提供依据。     

膜生物反应器处理轻工废水研究进展

阐述了膜生物反应器的工艺特点和国内外研究状况,介绍了近几年国内外利用膜生物反应器处理轻工业废水的应用实例。在此基础上分析了膜生物反应器存在的问题,并对膜生物反应器应用于轻工业废水处理进行了展望。     

涤纶织物碱减量工艺废水处理研究

针对某纺织工业涤纶织物碱减量工艺废水问题,采用酸化-沉淀及生物处理系统对废水进行处理。在酸化-沉降实验中,在废水中苯二甲酸(TA)质量浓度从19.8 g/L减少到2.75 g/L,去除率达到86%,很大程度上减少了生物处理系统的负载,但是通过酸化-沉淀后废水中的TA使生物降解性能明显减弱,BOD5/COD量从0.37~0.40减少到0.27~0.31。在生物处理实验中,设定进水COD为2 109 mg/L、TA质量浓度为524 mg/L,出水COD为63.17 mg/L、TA质量浓度为5.14 mg/L,去除率分别超过97%、99%。通过实验表明,在需氧型混合膜生物反应器(HMBR)中,生物降解TA物质达到97%;在厌氧型水解酸化生物反应器(HABR)中,生物降解TA仅达到2.3%。同时,在HABR和HMBR反应器中,COD除去率分别约为29.8%和67%。     

膜生物反应器处理食品工业废水的研究进展

阐述了膜生物反应器的工艺特点和国内外研究状况,介绍了近几年来国内外利用膜生物反应器处理食品工业废水的应用实例。在此基础上分析膜生物反应器存在的问题,对膜生物反应器应用于食品工业废水处理的前景进行了展望。     

粉末活性碳加强型膜生物反应器对污水中新型污染物的去除

评述了传统活性污泥法及膜生物反应器工艺对污水中新型污染物的去除效果及其存在的问题,介绍了采用吸附剂对现有膜生物反应器工艺进行加强的新工艺,并对其技术原理进行了探讨。该加强工艺将3种独立的工艺(即膜过滤、物理吸附和生物降解)联合在一个处理单元内,并使得所有的反应同时进行,其协同效应可有效提升污水中新型污染物的去除效率。认为随着膜生产成本的降低,这将是一项极有前景的深度污水处理技术,但鉴于新型污染物种类及物化性质的多样性,需对该工艺的普适性进一步研究,并对现场使用效果进行评价。其去除过程的反应动力学条件和影响因素,中间产物和最终产物的鉴别是今后研究的关键所在。     

膜生物反应器膜污染的研究进展

从膜的结构性质、反应器操作条件、处理液微生物性质三个方面介绍了膜生物反应器膜污染机理研究的进展,总结了优化膜生物反应器设计、调节膜生物反应器操作条件、在线超声控制、化学方法等膜污染控制的常用方法,对未来膜污染研究进行了展望。     

SRT对复合式MBR处理低C/N生活污水的影响研究

采用投加悬浮填料的复合式膜生物反应器(HMBR)处理低C/N生活污水,考察HMBR系统中HRT对COD和脱氮效果的影响,探究低C/N生活污水处理方案。结果表明HMBR处理低C/N生活污水的最佳SRT为25 d,HMBR运行稳定、抗冲击负荷能力强,此时COD和TN的去除率分别达到88%和64%以上,但SRT对NH_4~+-N去除效果影响不大,NO_2~--N和NO_3~--N含量在SRT为35 d时达到最高,分别为4.01mg/L和6.91 mg/L。     

钯膜反应器柴油重整制氢模拟与验证

为了研究钯膜反应器柴油重整制氢工艺的反应规律,对其进行热力学和动力学建模,并通过实验验证模型的准确性。采用顺序模块法将钯膜反应器分为连续的子反应器和子分离器,模拟钯膜反应器的反应分离耦合过程,通过灵敏度分析,研究钯膜反应器中各反应因素等对氢气收率的影响规律。结果表明,钯膜反应器较无膜反应器可突破热力学平衡的限制,减小反应体积,在低温下可获得较高的氢气产率。在一定条件下模拟结果与实验值误差为8.9%,证明该仿真模型可对实验研究起到预测和指导作用。     

膜生物反应器处理废气

综述了近年来国外用膜生物反应器处理废气的研究进展,涉及膜材料及膜组件、膜的质量传递、传质速率与生物降解动力学关系、膜生物反应器性能以及膜污染问题等,并与常规的生物法处理废气进行了比较.针对膜生物法处理废气仍然停留在实验室水平上,笔者认为今后应深入研究膜材料、传质与动力学、微生物学、膜污染以及成套系统研制等问题.     

PTA直接酯化过程动力学的研究

研究了不同工艺条件下精对苯二甲酸 (PTA)的直接酯化过程 ,分别按零级和一级动力学模型处理 ,得出了酯化反应的动力学模型 ,动力学模拟表明一级动力学模型更为接近实际生产过程。     

Laboratory simulation of municipal solid waste fermentation with leachate recycle

Municipal solid waste fermentation, simulating landfill conditions, was studied using five test cells operated at different temperatures. The digestion was carried out under enhanced conditions. Leachate recycle was set up in all the test cells. Depending on temperature, the digestion was complete (more than 90% biodegradable matter converted) in a period of 25 to 57 days. Optimum operating temperatures were in the range of 34 to 38°C. Two kinetic models were fitted to experimental data. Their kinetic constants were related to temperature using an Arrhenius expression. Landfill life operated under the studied conditions could be reduced to less than 2 years.     

1,6-己二醇二丙烯酸酯合成动力学

以固体酸SO_4~(2-)/TiO_2-SnO_2-ZnO为催化剂,丙烯酸和1,6-己二醇为原料,考察了催化剂加量、转速以及催化剂粒径对酯化反应速率的影响。在消除内外扩散影响的前提下,建立了固体酸催化合成1,6-己二醇二丙烯酸酯拟均相反应动力学模型,得到了相应的动力学方程参数,动力学模型预测的结果与实验结果吻合良好。     

Combined experimental and kinetic modeling studies for the conversion of gasoline range hydrocarbons from methanol over modified HZSM-5 catalyst

The reaction was carried out in fixed bed reactor. The effect of process variables on the activity of oxalic acid treated 0.5 wt% ZnO/7 wt% CuO/HZSM5 catalyst for the conversion of methanol to gasoline range hydrocarbons was studied. The catalyst was prepared by incipient wetness impregnation method. After impregnation the catalyst was treated with oxalic acid. The validity of kinetic model proposed for the methanol to gasoline range hydrocarbon process at zero time on stream was studied, from the experimental results obtained in a wide range of operating conditions. The kinetic parameters for various models were calculated by solving the equation of mass conservation in the reactor for the lumps of the kinetic models. The kinetic model fitted well for simulating the operation in the fixed bed reactor in the range of 635 to 673 K, with regression coefficient (R²) higher than 0.96.     

核桃壳苯酚离解活化动力学研究

通过不同反应温度和反应时间条件下反应体系中游离苯酚含量和残渣率的测定,运用阿伦尼乌斯方程及过渡态理论和动力学分析,探讨核桃壳-苯酚酸催化液相离解活化反应的反应机理.结果表明离解产物的游离酚含量和残渣率随反应时间的延长而减小,核桃壳-苯酚酸催化液相离解活化反应符合动力学双分子二级反应的吸热反应,其活化能为65.2 kJ/mol,指前因子为2.39×10⁶ min^-1,活化焓为65.2 kJ/mol,活化熵为-122.09 J/mol.     

The DSC thermal analysis of crystallization behavior in palm oil

Polymorphic behavior of palm oil crystals was studied by DSC isothermal analysis and microscopic observation. Different crystal forms developed specific spherulites depending on the degree of super-cooling from the melt. The A-form crystal was capable of forming a dotted spherulite and the B-form crystal of forming a dendritic spherulite. Experimental results of B form crystallization studied by the DSC and a microscope under kinetic conditions were evaluated using Avarami’s theory, since the behavior of the oil during crystallization related well to that of high polymers. The crystallization process was divided into nucleation and crystal-growth phases to facilitate a theoretical treatment similar to that of high polymers, providing crystals possessing overall structural regularity.     

Estimation of Kinetic Parameters for Hydrogenation Reactions Using a Genetic Algorithm

The kinetics of acetylene hydrogenation in a fixed‐bed reactor of a commercial Pd/Al₂O₃ catalyst has been studied. The hydrogenation reactor considered in this work is an essential part of a vinyl chloride monomer (VCM) plant. Three well‐known kinetic models were used to simulate the hydrogenation reactor under industrial operating conditions. Since none of the models provide appropriate prediction, the industrial data and calculated values were compared and optimum kinetic parameters were evaluated utilizing a genetic algorithm (GA) technique. The best kinetic parameters for the three models were determined under specified industrial operating conditions. The hydrogenation reactor was simulated using the estimated optimum kinetic parameters of the three models. Simulation results from the three models were compared to industrial data and the best kinetic model was found. This kinetic model with the evaluated optimum kinetic parameters can well predict the behavior of the industrial hydrogenation reactor to improve the performance of the process.     

超声场强化中药有效成分提取动力学模型

在中草药开发利用中,探索提高有效成分提取率的理论依据是中草药现代化研究的一个重要方面．目前大多数是通过实验方法,根据影响提取率的因素选取不同的水平条件来设计实验,优化工艺条件,缺少理论上的指导．有人将这些影响因素与有效成分溶出浓度联系起来,在Fick扩散定律的基础上对常规提取的动力学建立了一些数学模     

Study of the effect of BDMA catalyst in the epoxy novolac curing process by isothermal DSC

Epoxy novolac/anhydride cure kinetics has been studied by differential scanning calorimetry under isothermal conditions. The system used in this study was an epoxy novolac resin (DEN431), with nadic methyl anhydride as hardener and benzyldimethylamine as accelerator. Kinetic parameters including the reaction order, activation energy and kinetic rate constants, were investigated. The cure reaction was described with the catalyst concentration, and a normalized kinetic model developed for it. It is shown that the cure reaction is dependent on the cure temperature and catalyst concentration, and that it proceeds through an autocatalytic kinetic mechanism. The curing kinetic constants and the cure activation energies were obtained using the Arrhenius kinetic model. A suggested kinetic model with a diffusion term was successfully used to describe and predict the cure kinetics of epoxy novolac resin compositions as a function of the catalyst content and temperature. Copyright © 2003 Society of Chemical Industry