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Experimental study on secondary air mixing along the bed height in a circulating fluidized bed with a multitracer-gas method
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作者 Qingyu Zhang Leming Cheng +3 位作者 Kun Li Qixun Kang Qiang Guo Chaogang Wu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第6期54-62,共9页
A multitracer-gas method was proposed to study the secondary air(SA)mixing along the bed height in a circulating fluidized bed(CFB)using carbon monoxide(CO),oxygen(O_(2)),and carbon dioxide(CO_(2))as tracer gases.Expe... A multitracer-gas method was proposed to study the secondary air(SA)mixing along the bed height in a circulating fluidized bed(CFB)using carbon monoxide(CO),oxygen(O_(2)),and carbon dioxide(CO_(2))as tracer gases.Experiments were carried out on a cold CFB test rig with a cross-section of 0.42 m×0.73 m and a height of 5.50 m.The effects of superficial velocity,SA ratio,bed inventory,and particle diameter on the SA mixing were investigated.The results indicate that there are some differences in the measurement results obtained using different tracer gases,wherein the deviation between CO and CO_(2) ranges from 42%to 66%and that between O_(2) and CO_(2) ranges from 45%to 71%in the lower part of the fluidized bed.However,these differences became less pronounced as the bed height increased.Besides,the high solid concentration and fine particle diameter in the CFB may weaken the difference.The measurement results of different tracer gases show the same trends under the variation of operating parameters.Increasing superficial velocity and SA ratio and decreasing particle diameter result in better mixing of the SA.The effect of bed inventory on SA mixing is not monotonic. 展开更多
关键词 Circulating fluidized bed Secondary air injection Gas mixing Multitracer-gas method
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Mixing and Segregation Characteristics of Binary Granular Material in Tapered Fluidized Bed: A CFD Study 被引量:1
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作者 Harekrushna Sutar Chandan Kumar Das 《Engineering(科研)》 2012年第4期215-227,共13页
The particle flow pattern, mixing and granule segregation in a tapered fluidized bed have been studied along with the hydrodynamics. At first the bed of varying total mass and granule fractions is fluidized then the b... The particle flow pattern, mixing and granule segregation in a tapered fluidized bed have been studied along with the hydrodynamics. At first the bed of varying total mass and granule fractions is fluidized then the bed is defluidized to freeze the composition, the bed is sectioned to layers and the composition in each layer is determined by sieving. Materials used in the present study are dolomite and glass beads with different B.S.S Sizes. A series of unsteady, three fluid CFD simulations were performed using FLUENTTM 6.2. Simulation parameters viz. solution technique, grid, maximum packing fraction and operating conditions like gas velocity were investigated for relative effects on particle mixing and segregation. Good arrangement of solid volume fraction profile was obtained between the experimental results and simulation results for regular particles. 展开更多
关键词 mixING SEGREGATION Tapered Fluidized bed CFD Simulation
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Numerical simulation of local and global mixing/segregation characteristics in a gas–solid fluidized bed
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作者 Zhen Wan Youjun Lu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2022年第4期72-86,共15页
Researches on solids mixing and segregation are of great significance for the operation and design of fluidized bed reactors.In this paper,the local and global mixing and segregation characteristics of binary mixtures... Researches on solids mixing and segregation are of great significance for the operation and design of fluidized bed reactors.In this paper,the local and global mixing and segregation characteristics of binary mixtures were investigated in a gas–solid fluidized bed by computational fluid dynamics-discrete element method(CFD-DEM)coupled approach.A methodology based on solids mixing entropy was developed to quantitatively calculate the mixing degree and time of the bed.The mixing curves of global mixing entropy were acquired,and the distribution maps of local mixing entropy and mixing time were also obtained.By comparing different operating conditions,the effects of superficial gas velocity,particle density ratio and size ratio on mixing/segregation behavior were discussed.Results showed that for the partial mixing state,the fluidized bed can be divided into three parts along the bed height:complete segregation area,transition area and stable mixing area.These areas showed different mixing/segregation processes.Increasing gas velocity promoted the local and global mixing of binary mixtures.The increase in particle density ratio and size ratio enlarged the complete segregation area,reduced the mixing degree and increased the mixing time in the stable mixing area. 展开更多
关键词 Discrete element method Solids mixing Binary mixtures Fluidized bed
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Segregation/Mixing Behavior of Binary Particles and Formation of Double-Density-Fluidized Bed
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作者 韦鲁滨 边炳鑫 赵跃民 《Journal of China University of Mining and Technology》 2001年第1期1-5,共5页
The current separator with air dense medium fluidized bed can only turn out two products at the same time with a single separating density. The double density fluidized bed means that two separating areas with differe... The current separator with air dense medium fluidized bed can only turn out two products at the same time with a single separating density. The double density fluidized bed means that two separating areas with different densities are formed in a fluidized cascade. In each separating area, the bed density is uniform and meets the technical requirement of coal preparation respectively. Therefore, the processed materials can be separated into three products according to density. In this paper, the fluidized behaviors of binary dense media were experimentally studied and the distribution characteristics of particle concentration and bed density in different bed structure were discussed. The segregation and mixing mechanisms of binary dense media were analyzed. It was testified that the pyramidal part designed in the bed structure played a key role in the formation of double density fluidized bed. The pyramidal part intensified the segregation of binary particles between two separating areas and strengthened the mixing in the low density area, which made for the density uniform of the area. 展开更多
关键词 双密度层空气重介流化床 三产品分选 选煤工艺 干法选矿
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DRG背景下公立医院床位效率研究
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作者 张雨洁 许皓 +3 位作者 邹澳 徐丽 胡蓉 刘琛慧 《现代医院》 2024年第7期1066-1069,1074,共5页
目的分析医院各临床科室床位利用效率,为合理配置科室床位资源提供参考。方法以某三甲专科医院2022年度数据为基础,基于传统床位工作效率指标,引入CMI值进行调整,计算各科室床位的合理区间,结合数据包络分析法(DEA),综合评价各临床科室... 目的分析医院各临床科室床位利用效率,为合理配置科室床位资源提供参考。方法以某三甲专科医院2022年度数据为基础,基于传统床位工作效率指标,引入CMI值进行调整,计算各科室床位的合理区间,结合数据包络分析法(DEA),综合评价各临床科室投入产出效率,得出床位配置优化方向。结果被统计的39个科室中,10个科室床位设置不合理,其中需要增加床位的有5个科室,需要减少床位的有5个科室。结论利用CMI调整病床工作效率指标,结合DEA方法,可为医院动态调整临床科室床位数提供科学依据;医院应合理利用床位资源,科学规划科室床位。 展开更多
关键词 病例组合指数 床位工作效率 数据包络分析 床位配置优化
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气固微型流化床反应分析仪的理想流型判据分析
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作者 卢飞 鲁波娜 许光文 《化工学报》 EI CSCD 北大核心 2024年第6期2201-2213,共13页
微型流化床因具有气体返混小和可操作性强等优点,在反应动力学测量等领域备受关注。获得流型随操作参数的变化规律,才能实现微型流化床理想流型的有效调控。采用双流体模型耦合考虑结构的相间曳力(又称多尺度CFD)模拟了一系列A类和B类... 微型流化床因具有气体返混小和可操作性强等优点,在反应动力学测量等领域备受关注。获得流型随操作参数的变化规律,才能实现微型流化床理想流型的有效调控。采用双流体模型耦合考虑结构的相间曳力(又称多尺度CFD)模拟了一系列A类和B类颗粒在不同操作条件下的流化行为,结合颗粒浓度和气体停留时间分布(RTD)特征考察气速、床径和初始床高对气体返混行为的影响。研究表明,当微型流化床在初始鼓泡到湍动流态化之间操作时,才逼近颗粒全混流和气体近似平推流的运动状态。进一步分析气体RTD曲线形状特征(如拖尾、多峰等),提出采用斜度S<0.6作为微型流化床平推流判据,弥补了原判据[满足方差σ_(t)^(2)<0.25且峰高E(t)h>1]的不足,为微型反应分析仪的流型调控奠定了基础。 展开更多
关键词 气固微型流化床 平推流 停留时间分布 气体返混 多尺度 数值模拟
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1000 MW超超临界机组精处理系统改造及智能化升级
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作者 钱陈虎 拓凯 +3 位作者 陈明 刘天涯 雷俊茹 田文华 《能源科技》 2024年第1期56-60,共5页
某电厂2×1000 MW超超临界机组锅炉给水采用加氧处理(OT),利用西安热工研究院“火电厂高速混床运行性能诊断及优化专家系统”对精处理高速混床和再生系统进行诊断,发现运行末期泄漏离子、再生系统缺乏智能监控装置及再生酸碱用量大... 某电厂2×1000 MW超超临界机组锅炉给水采用加氧处理(OT),利用西安热工研究院“火电厂高速混床运行性能诊断及优化专家系统”对精处理高速混床和再生系统进行诊断,发现运行末期泄漏离子、再生系统缺乏智能监控装置及再生酸碱用量大等问题。应用树脂输送图像智能识别及控制仪(IRIC)和双层多孔板布水装置改造后,树脂体外再生过程实现了智能控制,树脂输送终点识别准确率100%;高速混床平均周期制水量增幅108%,出水Na^(+)和Cl^(-)含量均优于《火力发电机组及蒸汽动力设备水汽质量》(GB/T 12145—2016)要求,经济效益和安全效益显著。 展开更多
关键词 超超临界直流锅炉机组 高速混床 再生系统 智能升级 运行优化
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钱塘江河口盐官段混合式丁坝修建对水沙及河床影响的实测研究
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作者 李建雄 周磊 +3 位作者 徐洋洋 许嘉豪 段雪儿 夏春晨 《浙江水利科技》 2024年第3期57-63,70,共8页
钱塘江北岸古海塘堤脚加固工程中,辅助围堰施工的临时性管袋黏土混合式丁坝对工程的顺利进行、提高施工效率起着至关重要的作用,然而目前对其周围水沙运动的研究较少,且缺乏相关实测资料。考虑混合式丁坝修建的动态过程,利用无人机拍摄... 钱塘江北岸古海塘堤脚加固工程中,辅助围堰施工的临时性管袋黏土混合式丁坝对工程的顺利进行、提高施工效率起着至关重要的作用,然而目前对其周围水沙运动的研究较少,且缺乏相关实测资料。考虑混合式丁坝修建的动态过程,利用无人机拍摄水流视频结合LSPIV(粒子图像测速)处理技术对丁坝修建前、中、后期周围的流场进行分析,并对丁坝附近的地形进行跟踪测量,同时对不同潮差的水流含沙量进行现场测定。结果表明,丁坝具有改变水流方向,减少水流对河岸冲刷的作用,且丁坝越长,挑流作用越明显,为围堰施工提供了较为平缓的水流条件;混合式丁坝对坝后处的促淤效果明显,且坝后地形变化与含沙量密切相关,潮差越大,水体含沙量越高,丁坝后河床淤积幅度越大,有利于提高围堰的施工效率。研究成果对之后相关物理模型和数值模拟的研究提供数据支持。 展开更多
关键词 钱塘江河口 混合式丁坝 水流流场 河床变形 含沙量
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气液混合强化在固定床加氢过程中的应用进展
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作者 苏梦军 刘剑 +5 位作者 辛靖 陈禹霏 张海洪 韩龙年 朱元宝 李洪宝 《化工进展》 EI CAS CSCD 北大核心 2024年第1期100-110,共11页
炼油工业作为国民经济的支柱,在创造大量财富的同时,往往存在高能耗、高物耗和高污染的问题。固定床加氢技术是重要清洁炼油技术,在油品质量升级、产品结构调整、原油资源高效利用、生产过程清洁化进程中发挥了重要的作用。提高固定床... 炼油工业作为国民经济的支柱,在创造大量财富的同时,往往存在高能耗、高物耗和高污染的问题。固定床加氢技术是重要清洁炼油技术,在油品质量升级、产品结构调整、原油资源高效利用、生产过程清洁化进程中发挥了重要的作用。提高固定床加氢效率有助于充分利用石油资源、生产清洁燃料和实现生产过程的节能降耗。本文从固定床反应器滴流床加氢和液相加氢过程的氢油两相物料混合特性出发,综述了通过开发新型混氢设备和加氢工艺,强化气液混合过程,提高固定床多相催化加氢效率的应用进展,并提出固定床加氢反应过程气液混合强化技术发展趋势,为炼油化工生产过程提质增效、节能降碳新技术的开发提供参考。 展开更多
关键词 气液混合 固定床加氢 多相反应 传质 过程强化
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混床运行周期降低的原因及处理
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作者 杨晓波 王志勇 高超超 《化工管理》 2024年第5期127-129,共3页
陕西延长中煤榆林能源化工股份有限公司(简称“榆能化公司”)是中国污水近“零排放”企业之一,原水水质复杂,由地表水、回用水、再生水及少量的污水站产水混合而成。各类回用水占比较大,部分难去除离子长期在水系统内富集,导致脱盐水混... 陕西延长中煤榆林能源化工股份有限公司(简称“榆能化公司”)是中国污水近“零排放”企业之一,原水水质复杂,由地表水、回用水、再生水及少量的污水站产水混合而成。各类回用水占比较大,部分难去除离子长期在水系统内富集,导致脱盐水混床运行周期不稳定、树脂再生频繁、酸碱单耗增加,严重影响装置稳定运行。文章通过对混床进水离子含量、树脂交换容量及再生操作等方面原因分析,发现混床进水电导率是影响混床运行周期的关键因素,并通过对各类回用水进行分质利用等措施,使混床运行周期降低问题得到了有效解决。 展开更多
关键词 混床 周期 电导率 再生 交换容量
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脉动流化床内青刀豆颗粒的混合特性数值模拟
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作者 杨晓燕 楼晓华 +2 位作者 钱丹 李林建 许彤 《轻工机械》 CAS 2024年第2期23-29,共7页
青刀豆一般采用流化床装置进行速冻。为了解决其床层堵塞和聚集不良的问题,进一步提高青刀豆的混合效率,课题组建立了三维混合脉动流化床模型,将计算流体力学与离散单元法(computational fluid dynamics-discrete element method,CFD-D... 青刀豆一般采用流化床装置进行速冻。为了解决其床层堵塞和聚集不良的问题,进一步提高青刀豆的混合效率,课题组建立了三维混合脉动流化床模型,将计算流体力学与离散单元法(computational fluid dynamics-discrete element method,CFD-DEM)相结合,探究1,2,4和8 Hz 4种不同频率的脉动进口风速下青刀豆颗粒的流化混合情况。仿真结果表明:脉动流化床对于青刀豆颗粒混合具有一定改善作用,青刀豆颗粒的轴向混合强于径向混合,4 Hz时颗粒混合标准偏差值最小;当进口风速的频率接近颗粒的自主振动频率时,床层膨胀最明显,出现类似“共振”的现象;2 Hz时颗粒径向、轴向混合效果最佳,频率过大或过小对于流态化增强效果不明显。 展开更多
关键词 颗粒混合 青刀豆 三维混合脉动流化床 计算流体力学与离散单元法(CFD-DEM) 振动频率
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煤化工优质再生水处理工艺优化研究
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作者 吕剑明 李志平 +2 位作者 魏万强 王江山 张杰英 《煤化工》 CAS 2024年第4期24-27,共4页
针对RO+混床工艺处理煤化工优质再生水的周期制水量与处理水库水相比明显偏低,影响回用锅炉补水问题进行了原因分析,并进行了RO+EDI工艺替换RO+混床工艺处理优质再生水的中试研究。试验结果表明:采取RO+EDI工艺处理优质再生水时,再生水... 针对RO+混床工艺处理煤化工优质再生水的周期制水量与处理水库水相比明显偏低,影响回用锅炉补水问题进行了原因分析,并进行了RO+EDI工艺替换RO+混床工艺处理优质再生水的中试研究。试验结果表明:采取RO+EDI工艺处理优质再生水时,再生水回用率可从采用RO+混床工艺的30%提高至100%,产水电导率和硅含量达到相关锅炉进水标准要求,同时吨水产水成本可由1.63元降低至1.02元,工艺优势明显。 展开更多
关键词 煤化工 优质再生水 回用率 周期制水量 RO+混床工艺 RO+EDI工艺
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Effects of Airflow Field on Droplets Diameter inside the Corrugated Packing of a Rotating Packed Bed 被引量:4
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作者 Xu Chengcheng Jiao Weizhou +3 位作者 Liu Youzhi Guo Liang Yuan Zhiguo Zhang Qiaoling 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2014年第4期38-46,共9页
Rotating packing bed(RPB) has a better mixing performance than traditional mixers and shows potential application in the petroleum industry. However, acquisition of information about the mixing process directly throug... Rotating packing bed(RPB) has a better mixing performance than traditional mixers and shows potential application in the petroleum industry. However, acquisition of information about the mixing process directly through experiments is difficult because of the compact structure and complex multiphase flow pattern in RPB. To study the mixing characteristic, Fluent, the computational fluid dynamics(CFD) software, was used to explore the effect of airflow field on droplet diameter. For conducting calculations, the gas-liquid two-phase flow inside the packing was simulated with the RNG k-ε turbulence model and the Lagrange Discrete Phase Model(DPM), respectively. The numerical calculation results showed that coalescence and breakup of droplets can take place in the gas phase flow inside the packing and can be strengthened with increased rotating speed, thereby leading to the enlargement of the average diameter. 展开更多
关键词 ROTATING packed bed computational fluid dynamics GAS-LIQUID flow field diameter mixING
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Enhancing the activity of MoS_(2)/SiO_(2)-Al_(2)O_(3) bifunctional catalysts for suspended-bed hydrocracking of heavy oils by doping with Zr atoms 被引量:1
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作者 Yongde Ma Rengan Liang +4 位作者 Wenquan Wu Jiayin Zhang Yanning Cao Kuan Huang Lilong Jiang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第11期126-134,共9页
Developing catalysts with not only hydrogenation activity but also cracking activity is very important for the advancement of suspended-bed hydrocracking technology.Within this respect,MoS_(2)/SiO_(2)-Al_(2)O_(3)bifun... Developing catalysts with not only hydrogenation activity but also cracking activity is very important for the advancement of suspended-bed hydrocracking technology.Within this respect,MoS_(2)/SiO_(2)-Al_(2)O_(3)bifunctional catalyst is a kind of typical catalysts with both hydrogenation and cracking activity.Herein,a series of Zr-doped SiO_(2)-Al_(2)O_(3)mixed oxides were synthesized by a sol-gel coupled with hydrothermal method.The synthesized mixed oxides were characterized for chemical structures and acidic properties.It is found that doping SiO_(2)-Al_(2)O_(3)with Zr atoms significantly increases the numbers of acidic sites.The Zr-doped SiO_(2)-Al_(2)O_(3)mixed oxides were then combined with dispersed MoS_(2),which was in-situ produced from oil-soluble Mo precursors,to fabricate a novel kind of bifunctional catalysts for suspended-bed hydrocracking of heavy oils.Owing to the significantly increased numbers of acidic sites in Zr-doped SiO_(2)-Al_(2)O_(3)mixed oxides,corresponding bifunctional catalysts demonstrate much enhanced activity for suspended-bed hydrocracking of heavy oils in relative to MoS_(2)/SiO_(2)-Al_(2)O_(3)bifunctional catalysts. 展开更多
关键词 Petroleum HYDROGENATION Catalyst Suspended bed CRACKING mixed oxide
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Modeling of the Precipitation Process in a Rotating Packed Bed and Its Experimental Validation 被引量:2
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作者 向阳 文利雄 +3 位作者 初广文 邵磊 肖光庭 陈建峰 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2010年第2期249-257,共9页
A mixing-precipitation model based on the modified coalescence-redispersion model was presented to describe the flow,mixing,nucleation and growth in a rotating packed bed(RPB) .The model was coupled with population ba... A mixing-precipitation model based on the modified coalescence-redispersion model was presented to describe the flow,mixing,nucleation and growth in a rotating packed bed(RPB) .The model was coupled with population balance,mass balance and crystallization kinetics.It predicted well the influence of coalescence prob-ability,which represents the mixing intensity among droplets,on the particle number density,supersaturation and mean particle size of the produced precipitates.The effects of the radial thickness of packing,liquid flow rate and rotating speed on the product particle size were also investigated.The results indicate that the needed radial length of packing is short for sparingly soluble substance precipitation(about 40-50 mm in this work) ,and the mean parti-cle size of precipitates decreases with the increase of rotating speed and liquid flow rate,respectively.The validity of this model was verified by experiment on BaSO4 precipitation in RPB. 展开更多
关键词 旋转填料床 降水过程 验证 实验 沉淀硫酸钡 旋转填充床 粒子数密度 模拟
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Axial Liquid Dispersion Characteristics in Magnetically Stabilized Bed
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作者 张东利 张艳君 +4 位作者 张金利 李晓芳 卢立祥 孟祥坤 慕旭宏 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2006年第4X期532-536,共5页
关键词 MAGNETICALLY STABILIZED bed AXIAL LIQUID dispersion back mixING
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FUNDAMENTAL STUDIES ON THE HYDRODYNAMICS AND MIXING OF GAS AND SOLID IN A DOWNER REACTOR
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作者 汪展文 魏飞 +1 位作者 金涌 俞芷青 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1997年第3期48-57,共10页
The effect of flow direction on hydrodynamics and mixing in the upflow and downflowcirculating fluidized beds is discussed in details.Similar profiles of gas and solids velocities andsolids concentration are found in ... The effect of flow direction on hydrodynamics and mixing in the upflow and downflowcirculating fluidized beds is discussed in details.Similar profiles of gas and solids velocities andsolids concentration are found in both risers and downers.When the flow is in the direction ofgravity(downer),the radial profiles of gas and particle velocity are more uniform than that inthe riser,the solids mixing is very small and the flow pattern approaches plug flow,while theflow is against gravity(riser),the solids backmixing significantly increase and the flow pattern isfar from plug flow.Among many of factors the flow direction has the largest influence onhydrodynamics and axial mixing of gas and solids. 展开更多
关键词 CIRCULATING fluidized bed GAS-SOLID mixING RTD
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Hydrodynamics and oxygen transfer in a novel extra-loop fluidized bed bioreactor
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作者 陆永生 DAGOT Christophe +2 位作者 BAUDU Michel LAURENT Julien 胡龙兴 《Journal of Shanghai University(English Edition)》 CAS 2010年第4期266-274,共9页
In this paper, the characteristics of fluid mixing time in a novel extra-loop fluidized bed were studied. The results showed that the mixing time was shortened with the increase of fluid velocity. All the discrete num... In this paper, the characteristics of fluid mixing time in a novel extra-loop fluidized bed were studied. The results showed that the mixing time was shortened with the increase of fluid velocity. All the discrete numbers of the reactor were above 0.2. The serial number n was 2.5 -3.0. It was judged accordingly that the reactor fluid state was continous stirred tank reactor (CSTR) mainly. When the inspiratory capacity increased the mixing time of the reactor was shortened. Thus the air input was beneficial for the fluid mixing. During the three phases mixing process, the mixing time of the reactor could be decreased by the n increase of carrier and air loading together, but the change was not significant. The parameters affecting the reactor fluid state were fluid velocity, inspiratory capacity and carrier. KLa could be increased with the air loading increase, and at the same gas/liquid ratio when the pressure drop was high, KL~ value was increased. The amount of carrier complex influence on KLa. As the carrier loading continued to increase, its value had been dropped but the changes was not significant, and optimization condition was found at above 800 1 000 g carrier loading (pouzzolane) or 600 g PVC. Under gas/liquid ratio of 0.8% -5.2%, KLa was (0.62-1.37)×10^-2· s^-1. 展开更多
关键词 extra-loop fluidized bed mixing time oxygen transfer fluid velocity Venturi aero-ejector carrier
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Kinetic Studies for an Aerobic Packed Bed Biofilm Reactor for Treatment of Organic Wastewater with and without Phenol
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作者 Sudipta Dey Somnath Mukherjee 《Journal of Water Resource and Protection》 2010年第8期731-738,共8页
A laboratory scale aerobic fixed film bioreactor packed with glass beads for biofilm growth was used to evaluate the removal efficiencies of COD and phenol for a carbohydrate—phenol mixture in wastewater. It was done... A laboratory scale aerobic fixed film bioreactor packed with glass beads for biofilm growth was used to evaluate the removal efficiencies of COD and phenol for a carbohydrate—phenol mixture in wastewater. It was done by an indigenous mixed culture inoculums developed after collecting sludge from a return line of an activated sludge plant. The test result on continuous flow in the above biofilm reactor indicated an optimum hydraulic loading range of 4-6.4 m3day-1m-2 for attainment of reasonable amount of COD removal in case of carbohydrate substrate only. The COD removal efficiency, however, gradually depleted from 100% to 54% by gradual increase in organic loading (OLR) from 0.72-4.32 kgday-1m-3, beyond which removal was not significant. For the identical loading conditions, in presence of phenol in the substrate along with carbohydrate, the COD removal was observed varying from 100-40% in the above organic loading range. The COD removal kinetics in presence of phenol also shows a decreasing trend compared to data obtained without the presence of phenol in wastewater that reveals biological inhibition. The experimental data were fitted in a simple plug flow model for evaluating the zero order, first order and Monod form of rate equations to evaluate the kinetics. It was found that Monod type rate equations combining a zero and first order rate expression is the best fit for the above hydraulic and organic loading that gives a best fit half velocity constant value of 35 mgL-1 (R2 = 0.9612). 展开更多
关键词 Packed bed Reactor BIOFILM mixed Culture COD Removal PHENOL KINETIC Model
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循环荷载下TDA掺量对一级道砟动力性能的影响 被引量:2
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作者 常建梅 李翔 +3 位作者 李晓慧 魏亚辉 张伏光 冯怀平 《中国铁道科学》 EI CAS CSCD 北大核心 2023年第1期78-86,共9页
掺和废旧轮胎橡胶颗粒(TDA)改良道砟具有降低道砟磨耗、缓解废料处置压力、便于施工等诸多优点,是一种具有发展潜力的道床改良措施。采用动三轴试验和激光扫描方法,进行循环荷载作用下TDA掺量(体积比)对TDA一级道砟混合集料动力性能的... 掺和废旧轮胎橡胶颗粒(TDA)改良道砟具有降低道砟磨耗、缓解废料处置压力、便于施工等诸多优点,是一种具有发展潜力的道床改良措施。采用动三轴试验和激光扫描方法,进行循环荷载作用下TDA掺量(体积比)对TDA一级道砟混合集料动力性能的影响及道砟颗粒几何形状变化规律的研究。结果表明:随着TDA掺量的增加,混合料试样轴向应变增加、动弹性模量降低、阻尼比增加,且道砟破碎率降低;TDA掺量为10%时,可在保证混合料动弹性模量和阻尼比满足要求的前提下,有效降低道砟颗粒破碎率;循环荷载作用下道砟主要在尖角、棱边及表面发生局部破坏,颗粒整体形状特征变化较小;与不含TDA试样相比,TDA掺量为10%试样的道砟颗粒局部特征综合系数减小16%,TDA可有效降低道砟颗粒局部破坏程度。 展开更多
关键词 道床 道砟混合集料 TDA 几何形状 动三轴试验 循环荷载
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