三维流化床电极法深度处理焦化废水的研究

对三维流化床电极法深度处理焦化废水进行了研究,取得了相应的适宜工作参数.研究结果表明,三维流化床电极反应器能有效地对焦化废水生化出水进行深度处理.在反应时间为60 min、槽电压15 V、曝气量0.3 m3/h、pH为2、活性炭100 g/L时,三维流化床电极法能使焦化废水CODCr去除率>65%.     

三维电极催化氧化研究进展

三维电极技术是处理废水的有效手段,整理了近几年国内外关于三维电极催化氧化技术最新的研究情况和特点,介绍了三维电极反应器的类型,对反应器采用的主电极材料、粒子电极的改进进行了论述,总结了三维电极技术耦合其它技术的处理效果,提出了该技术目前的不足及未来的研究方向。     

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。     

三维电极处理含盐污水的试验研究

目前，海水直接利用后排放的污水及其他工业中排放的含盐污水的处理成为人们普遍关注的问题。本研究采用活性炭三维电极反应器对含盐污水的处理进行了试验研究，分析了电压、电解时间、初始pH值和绝缘粒子投加量等因素对水中污染物质的去除效果的影响，用CODCr的变化来表征。结果表明：三维电极反应器处理含盐污水工艺对污染物质的去除效果...     

新型三维电极生物膜工艺强化脱氮除磷特性

针对常规三维电极生物膜工艺脱氮除磷时难以达到高效、同步的脱氮除磷效果,将海绵铁、硫磺与活性炭填料复合用于常规工艺中以提高脱氮除磷效率。实验结果表明,在不同电流强度下,新型反应器对TN和TP的去除率最高可达到80%和92%,分别比常规反应器要高出15%和32%左右。综合经济、运行效果等因素,新型三维电极生物膜反应器在300 m A电流条件下,选择6 h的水力停留时间为适宜运行条件。     

复极性三维电极反应器处理氨基酸发酵废水

本文利用以活性炭颗粒为粒子电极的复极性三维电极反应器来处理氨基酸发酵废水,考察了外加电压、处理时间、进水pH和活性炭粒径对废水处理效果的影响.结果表明:相比于传统的二维电极,活性炭粒子电极的加入有效地提高了有机污染物的降解效果,并且填充活性炭粒径过大或过小都会降低处理效率,反应体系在酸性条件下处理效率较高.废水COD去...     

不同3D-BER反应器去除地下水中NO_3~--N的研究

采用平板式、中心式2种构型的三维生物膜电极反应器(3D-BER)对模拟的污染地下水中的NO_3~--N进行处理,研究了水力停留时间(HRT)、电流、进水NO_3~--N浓度和pH这4种影响因素对2种反应器脱氮效果的影响。结果表明:平板式、中心式3D-BER反应器适宜的HRT均为12 h,最佳的电流范围均为40~50 mA,对应的最大NO_3~--N去除率分别为82.67%、71.89%,理想的进水NO_3~--N分别为35~55、20~35 mg/L,平板式3D-BER反应器对进水NO_3~--N负荷具有更高的承受能力,中心式3D-BER反应器由于具有较好的阴极和阳极产物混合条件,对进水pH具有更强的缓冲能力。     

不同粒子电极对三维电极法处理苯酚废水影响的研究

研究不同粒子电极对三维电极法处理苯酚废水的影响.采用自制的三维电极反应器,以模拟苯酚废水为处理对象,通过试验分析不同类型活性炭、活性炭不同投加量、石英砂与活性炭混合以及活性炭与涂膜活性炭混合粒子电极对苯酚去除效果的影响.结果表明采用3 mm的柱炭,活性炭量为500 g时苯酚去除效果较好;石英砂与活性炭混合粒子电极比单纯活性炭处理效果好,但去除率提高不明显;在相同条件下采用比例为3:1的活性炭与涂膜活性炭作为粒子电极时,苯酚去除率最高为90.52%.     

炭膜与三维电极耦合处理高含盐染色废水的研究

以高含盐高COD染色废水为处理对象,研究新型的炭膜与三维电极耦合技术对其降解过程.通过对比三维电极工艺,考察了炭膜与三维电极耦合技术降解高含盐高COD染色废水的优越性,并研究了反应器参数对耦合技术处理效果的影响.结果表明,电极间距1.0cm,电流密度30 mA·cm-2,反应时间4 h,石墨玻璃珠混合物为粒子电极时,炭膜与三维电极耦合技术可将废水COD从4514mg·L-1下降到1050mg·L-1,COD去除率达到77%,对比三维电极电解过程,COD去除率提高34.2%.试验证明炭膜与三维电极耦合处理高含盐高COD染色废水是可行的集成技术.     

复极性三维电极反应器处理焦化废水主要影响因素研究

以经吸附处理的活性炭-涂膜活性炭为填充粒子,对复极性流化床三维电极反应器处理焦化废水进行了静态条件试验研究。主要探讨了通气量、电解时间、涂膜活性炭比、槽电压对COD去除率的影响。结果表明,通气量为1．5L／min,通电时间为60min,涂膜活性炭比为45％,槽电压为6V时,COD去除率最高,达87％。废水主要成分也发生了较大变化。     

Observation of 3‐D Structure of Bubbles in a Fluidized Catalyst Bed

The interface area between the bubble and emulsion phases in a fluidized catalyst bed is one of the important parameters used to analyze and design the fluidized bed reactor. We used a fast‐scanning X‐ray CT system to observe the bubble shape and structure. We then obtained the transient 2‐dimensional cross sectional gas‐phase distribution in a fluidized catalyst bed. Using image‐processing techniques, pseudo 3‐dimensional images of the bubbles were reconstructed. The bubble structure was studied based on the 3‐dimensional images and the previously obtained results in a 2‐dimensional fluidized bed. It was found that the bubble shape was not spherical but complicated, and that the bubbles ascending in a fluidized catalyst bed consisted of some smaller bubbles.     

Studies of bipolarity in fluidized bed electrodes

Measurements have been made of the anodic reaction products due to the anodic over-potential resulting from the bipolarity of particles in a nominally cathodic fluidized bed electrode reactor. Investigations of the lead particle-basic carbonate solution system show that charge transfer occurs by a bipolar as well as a monopolar mechanism in a nominally monopolar fluidized bed electrode. The bipolar intensity was found to increase with decreasing superficial current density and also with increasing bed voidage.     

IMPORTANCE OF DISPERSED SOLIDS IN BUBBLES FOR EXOTHERMIC REACTIONS IN FLUIDIZED BEDS

Ignition of activated carbon particles were measured in a vertical tube reactor of 4 cm ID, where single particles fell consecutively through a gas mixture containing oxygen.

A two dimensional fluidized bed reactor 24 cm wide, 51 cm high and 2.5 cm in thickness was used for visual observation through a wide front window 24 cm × 35 cm covered with a silica glass plate 1 cm thick. Activated carbon particles were fluidized incipientiy by air, and a gas mixture containing oxygen was injected upwards into the bed through a nozzle positioned 5 cm above the distributor, forming single bubbles intermittently.

It was observed that carbon particles dispersed in rising bubbles were ignited abruptly at emulsion phase temperatures above 550°C. Experimental findings from the fluidized bed were compared with those from the tube reactor, suggesting that the igniting conditions for particles dispersed in bubbles are nearly the same as for single particles falling in the tube reactor.     

Modelling and simulation of an oxychlorination reactor in a fluidized bed

Taking 1,2‐dichloroethane from the oxychlorination reaction is a commercially very important process due to the large application of the 1,2‐dichloroethane in the chemical industry of PVC production. This work presents the modeling and simulation of an oxychlorination reactor with a fluidized bed. The pseudo‐homogeneous model with one‐dimensional flow in steady state was applied based on the theory of fluidized bed in two phases. It allows the sensitivity analysis of the operational and project parameters of the reactor. The ordinary differential equations system that represents the mathematical model of the reactor was solved through the application of the numerical method of Newton–Raphson's. The results obtained have proved that the developed model represents the system suitably, in spite of the one‐dimensional model. The effect of different parameters was investigated through the sensitivity analysis, and the results show that the parameters that have the largest influence on the reactor performances are: fluidized bed height, bubble diameter, residence time, cupric chloride weight in the catalyst, and emulsion phase temperature.     

IMPORTANCE OF DISPERSED SOLIDS IN BUBBLES FOR EXOTHERMIC REACTIONS IN FLUIDIZED BEDS

Ignition of activated carbon particles were measured in a vertical tube reactor of 4 cm ID, where single particles fell consecutively through a gas mixture containing oxygen.

A two dimensional fluidized bed reactor 24 cm wide, 51 cm high and 2.5 cm in thickness was used for visual observation through a wide front window 24 cm × 35 cm covered with a silica glass plate 1 cm thick. Activated carbon particles were fluidized incipientiy by air, and a gas mixture containing oxygen was injected upwards into the bed through a nozzle positioned 5 cm above the distributor, forming single bubbles intermittently.

It was observed that carbon particles dispersed in rising bubbles were ignited abruptly at emulsion phase temperatures above 550°C. Experimental findings from the fluidized bed were compared with those from the tube reactor, suggesting that the igniting conditions for particles dispersed in bubbles are nearly the same as for single particles falling in the tube reactor.     

Thin polymer films from fluidized electrode bed reactors

The formation and deposition of a polymer as a thin, uniform solid film on a metal particle substrate is investigated in detail in a fluidized electrode bed reactor. Experiments were carried out in different designs of fluidized bed electrode cell reactor, using various metal particles and monomers. It was observed that diacetone acrylamide (DAA) monomer in 0.1N H₂SO₄ with aluminum particles (3530 μm) as cathode, in a concentric dual compartment cell, appeared to yield the best films. Infrared and elemental analyses were used to characterize the polymer film on the metal particles. Scanning electron microscopy (SEM) was employed to examine the surface and cross-sectional profiles of the films. The potential profiles in both particulate and solution phases were measured and the importance of particulate electrical conductivity in the polymerization is thus explained. It was observed that the optimum particulate conductivity and hence the maximum yield occurs in the range of 10–20% bed expansion. The experimental product yields for various liquid superficial velocities (i.e., bed expansion) at different feeder current densities were compared to explain the possible controlling mechanism in packed and fluidized bed cells, noting that both chemical reaction and mass transfer control in the low bed expansion region while chemical reaction controls in the high bed expansion region. The current effciency decreases in the high current region due to side reactions at the fluidized bed electrode and due to pore diffusion in the polymer film.     

丁烷氧化制顺酐循环流化床反应系统的温度匹配(I)反应系统模型

以VPO催化剂上正丁烷选择氧化制顺酐为例 ,对以变价金属复合氧化物为催化剂、按照氧化 -还原机理进行的一大类烃类选择氧化反应催化循环的温度匹配问题进行了初步模拟 .结果表明 ,使烃类选择氧化 (催化剂被还原 )和催化剂氧化再生分开进行 ,特别是根据催化剂氧化再生动力学的要求 ,适当调节再生过程的温度 ,既能明显改善反应系统的性能 ,又可以大幅度降低催化剂固体颗粒的循环量 ,取得节能降耗的效果 .本文介绍模型的建立和求解方法     

液固提升管-流化床组合反应器中流化床径向固含率分布的实验研究

在一套新型液固提升管-流化床组合反应器中,以水-玻璃珠为液-固体系,对f500 mm′4000 mm的液固流化床反应器内不同高度颗粒固含率的径向分布进行了实验,考察了表观液速和颗粒循环速率操作条件对颗粒固含率径向分布的影响. 实验表明,液固流化床内流动区域在轴向上可以划分为分布器影响区、过渡区和均匀流化区,径向上可以划分为中心区和环隙区. 这种分布特征主要取决于分布器的结构、尺寸及其流化介质. 本工作还对液固流化床与气固喷动床的三区流动结构进行了比较.     

Enhancement of mass transfer in the fluidized bed electrode reactors

With the view of developing the fluidized bed electrode system, mass transfer coefficient, overpotential distribution, and copper degradation have been observed in this investigation. Particles whose diameters were one of 327, 388, 510, 548, 750, and 960 μm were fluidized by the 1,000 ppm copper sulfate electrolyte. This study used two types of the experimental reactor. One had 5x5.5 cm bed-dimension with various thickness in a rectangular side-by-side configuration; the other 3.2 cm bed-diameter with various height in a cylindrical flow-through configuration. Mass transfer coefficient increased with increasing particle diameter, and the optimum fluidization was obtained at the condition of bed porosity near 0.65. For processing a large fluidized bed reactor, the expansion of bed height at a distance between electrodes was found to be more effective than the enlargement of bed thickness between electrodes. By replacing a three-dimensional current-feeder with a plane feeder, degradation and residual concentration of copper ion in a batch recycling mode could be achieved to be higher than 99% and less than 5 mg/L, respectively.     

流化床在甲烷临氧CO2重整反应中的作用研究

在流化床反应器中进行甲烷临氧CO₂重整制合成气反应。通过计算分析了催化剂颗粒在床层内的流化特性。对比实验表明,流化床反应器在催化剂活性、稳定性、自热过程以及催化剂积炭等方面均体现出比固定床反应器的优越性。在流化床反应器中进行的甲烷自热重整反应,甲烷的转化率接近热力学平衡值,床层温度梯度小于10 ℃, 反应20 h后,催化剂表面无积炭。