Intensification principle of a new three-phase catalytic slurry reactor. Part II: Eco-efficiency and techno-economic performances

In two papers, the concept and the performances of a new continuous intensified reactor named RAPTOR^® (French acronym for Reactor with Polyvalent Rectilinear Stirred Reactor with Optimised Transfer) are presented.Based on flow, heat and mass transfer characterisations and real hydrogenation experiments, Paper I presented a simple analytical model based on characteristic times that enables to explain the intensified performances compared with a semi-batch stirred reactor and to generalise the operability, rapidity and the flexibility of this minireactor. In Paper II (this article), the model is used to evaluate in a comparative study the eco-efficiency and the techno-economical advantages of a continuous process involving a RAPTOR^® versus a classical batch process equipped with a stirred reactor. Economical, environmental aspects are considered as well as productivity, safety and process control.     

三诺西与次氯酸钠预氧化效果对比研究

该文采用一种新型的消毒剂(三诺西)对某水厂原水进行预氧化试验研究,考察了三诺西在预氧化过程中对藻类、叶绿素、细菌等去除效果,并与水厂现有预氧化剂次氯酸钠对比预氧化性能。结果表明,三诺西在水中有效成分衰减缓慢,可以保持水中稳定的残余有效成分浓度,具有持续的氧化能力,对叶绿素a去除效果较好,优于次氯酸钠去除效果,但对藻类和细菌去除效果不及次氯酸钠。     

突发溴氰菊酯污染的应急处理工艺中试研究

溴氰菊酯是净水厂原水突发水质污染的高风险物质之一。通过中试研究了原水突发溴氰菊酯污染的应急处理工艺。结果表明,仅靠常规工艺难以有效应对原水突发溴氰菊酯污染;向原水中投加粉末活性炭(PAC)与强化常规处理工艺联用可有效去除水中溴氰菊酯,保证处理后水质达到生活饮用水卫生标准要求;炭液混合和混凝澄清阶段是溴氰菊酯去除的主要阶段,去除率为42%～98%;炭砂滤柱通过吸附截留水中载有溴氰菊酯的微小絮体颗粒,实现进一步去除水中溴氰菊酯的目的;颗粒炭滤柱作为安全余量,是水质安全保障的最后关口。基于中试结果,给出了应对原水突发溴氰菊酯污染时PAC对溴氰菊酯的吸附能力。     

黄浦江水源突发挥发酚污染应急处理研究

针对黄浦江上游水源可能发生的突发挥发酚污染事故,开展应急处理小试和中试研究,考察了混凝、PAC吸附和PAC吸附-常规工艺对原水中挥发酚的应急处理能力。结果表明,强化混凝方法无法有效应对原水突发挥发酚污染问题。PAC对原水中苯酚的Freundlich吸附等温式为q_e=0.428 6 C_e~(0.240 8),根据该式求得当原水苯酚浓度为0.008 mg/L时,PAC吸附应急处理的理论投加量为12 mg/L。PAC强化常规工艺可作为应急措施有效应对突发酚污染事故,当原水苯酚超标浓度为0.008 mg/L时,PAC最佳投加量为10 mg/L。     

Mechanism of heterogeneous catalytic ozonation of nitrobenzene in aqueous solution with modified ceramic honeycomb

The degradation efficiencies of nitrobenzene in aqueous solution were investigated by semi-continuous experiments in the processes of ozone alone, ozone/ceramic honeycomb (CH) and ozone/modified ceramic honeycomb (MCH). MCH with 1.0% Mn and 0.5% Cu had more pronounced catalytic ability than CH to accelerate the degradation of nitrobenzene, to increase the utilization efficiency of ozone, to improve the concentrations of hydrogen peroxide (H₂O₂) formation and hydroxyl radical (OH) initiation, and to enhance the removal efficiency of TOC. The modification process of CH with the metals enhanced the density of surface hydroxyl groups, which determines the initiation of OH from ozone decomposition and the generation of intermediate species on heterogeneous catalytic surface, yielding the acceleration of the degradation of nitrobenzene in aqueous solution. Possible reaction mechanism of ozone with heterogeneous catalytic surface in aqueous solution was proposed, and the formation mechanism of H₂O₂ and OH was also discussed according to the combined reactions in heterogeneous and homogeneous catalytic systems.     

Fixed-bed ion exchange columns operating under non-equilibrium conditions: Estimation of mass transfer properties via non-equilibrium modeling

The present work describes a new technique for the estimation of particle film mass transfer coefficients, k_f and homogeneous solid diffusivity, D_hs for resins in fixed-bed ion exchange columns under non-linear adsorption isotherm conditions. The experimental set-up is composed of a fixed-bed ion exchange column operating under recycling flow, and a reservoir. The experiments are carried out with custom made para-magnetic composite ion exchange resin filled columns. The single pass non-equilibrium packed-bed adsorption model is adapted to the present recirculation system and the model equations are numerically solved by the implicit schemes of the finite differences technique for predicting the mass transfer parameters. In order to find the k_f values, model predicted reservoir concentration profiles for early-time data are generated, and different k_f values were substituted into the model until the predicted and the experimental reservoir vs. time profiles agree. Once k_f is known, a second version of the model is used by substituting different D_hs values where no time constraint is made. When the model output and the experimental reservoir concentration profiles agree, the corresponding D_hs value is taken as the homogeneous solid diffusion coefficient. The present methodology allows the experimental determination of k_f and D_hs values for fixed-bed ion exchange columns through a simple recirculation system.     

Dissolved Air Flotation in Combination with Ultrafiltration Membrane Modules in Surface Water Treatment

气浮与超滤膜联用技术在地表水处理中的研究

时玉龙^1,2,马 军^1,2,武道吉³,潘 芹⁴

（1.哈尔滨工业大学 城市水资源开发利用<北方>国家工程研究中心,哈尔滨 150090;2.城市水资源与水环境国家重点实验室（哈尔滨工业大学）,哈尔滨 150090;3.山东建筑大学 市政与环境学院,济南 250101;4.淮南首创水务有限责任公司,安徽 淮南 232003)

创新点说明：

1）将气浮与超滤膜组合工艺应用于地表水处理;

2）气浮作为超滤膜预处理工艺可以有效削减后者的固体颗粒物负荷;

3）在气浮与帘式超滤膜组件之间引入由颗粒活性炭与沸石组成的复合滤料,强化了系统对有机物与氨氮的去除。

研究目的：

考察气浮与超滤膜组合工艺对实际水体的处理效果。探索出适用于地表水处理的最优工艺组合形式。

研究方法：

将沿淮某水厂气浮单元分别与管式、帘式超滤膜组件联用。研究两种组合工艺对淮河原水中浊度、UV254、氨氮、颗粒数（＞2 μm）及微生物指标的控制情况。并对膜组件的运行参数进行全程观测。

结果：

气浮对絮体颗粒的显著去除,强化了管式超滤膜对颗粒污染物的截留效果,但膜柱内出现细菌滋生及亚硝酸盐氮积累,此外,滤后水氨氮含量时常超过标准限值。在气浮与帘式超滤膜间装填颗粒活性炭与沸石滤料,组成的气浮-复合滤料膜生物反应器工艺中,气浮充氧促进了滤料表面生物膜对氨氮、有机物污染物的吸附、降解,帘式超滤膜对微生物的高效截留,即保证了反应器内部充足的生物量,又消除了上向流生物滤池可能存在的生物泄露风险。并且较压力式超滤膜,表现出良好的抗生物污染性能。

结论：

气浮与超滤膜组合工艺在地表水处理领域具有很好的应用前景,气浮与管式、帘式超滤膜联用均可对致浊颗粒物形成高效去除。其中,气浮-复合滤料膜生物反应器工艺更适用于处理溶解性污染物突出的水体。

关键词：气浮;超滤膜;颗粒活性炭;沸石;膜污染

     

Biomass-derived N-doped porous activated carbon as a high-performance and cost-effective pH-universal oxygen reduction catalyst in fuel cell

Nitrogen (N) doped porous activated carbons (TGC-T) derived from tofu gel are prepared through a facile, economic and eco-friendly method. The as-prepared TGC-900 possesses high specific surface area (651.78 m² g⁻¹) and homogeneous doping N (Content of N: 5.52 at.%). Reasonably, TGC-900 exhibits excellent oxygen reduction reaction (ORR) activity, stability and methanol resistance in neutral, alkaline and acidic medium. Moreover, TGC-900 also shows outstanding ORR performance in the application of microbial fuel cell (MFC) with the highest output voltage (544 ± 6 mV) and maximum power density (977 ± 32 mW m⁻²). Inspiringly, four single-chamber air cathode MFCs (AC-MFCs) in series can drive a light-emitting diode (LED) to work is firstly reported which further provides a more intuitively method to evaluate the performance of generating electricity for MFCs. Thus, the high performance and cost-effective ORR catalyst TGC-900 is expected to apply in the field of fuel cells.     

The peculiar influence of the mineral impurities content in coal-water fuel on the regularities of fuel drop ignition and combustion

This paper presents the results of the comparative research of combustion specifics of coal-water fuel produced from low-ash and high-ash Ukrainian flame coal. The analysis shows that the effect of the ash content in the coal-water fuel on the duration of the burning of a fuel drop depends on the drop size. The full combustion time of CWF drop based on the low-ash coal can be both less and longer than that of high-ash coal under the identical conditions for different equivalent diameters of the fuel drop. This specific is explained with the domination of different physical factors during the fuel combustion process.The results of this research extend significantly our knowledge of coal-water fuel, allow understanding some issues of its combustion and are important for the design of the specialized energy facility which is used coal-water fuel as an energy source.