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Air Flotation Towing Characteristics of an Integrated Wellhead Platform
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作者 LE Conghuan ZHANG Yuyang +2 位作者 BAI Yu ZHANG Puyang DING Hongyan 《Journal of Ocean University of China》 2025年第3期605-617,共13页
This study investigates the wet towing characteristics of an integrated wellhead platform supported by a bucket foundation.These characteristics are crucial for optimizing offshore construction efficiency and enabling... This study investigates the wet towing characteristics of an integrated wellhead platform supported by a bucket foundation.These characteristics are crucial for optimizing offshore construction efficiency and enabling the development of small marginal oil fields.The wet towing behavior of the integrated wellhead platform was explored through a combination of physical experiments and numerical simulations.Physical experiments were conducted to validate the accuracy of the numerical simulations.Subsequently,numerical simulations were employed to determine the impacts of towing speed and wave direction on the towing process of the integrated wellhead platform.Finally,the impact of compartment failure due to bulkhead damage on towage stability was analyzed.Findings indicate that the wave and towing directions influence the motion of the platform at various degrees of freedom.The platform demonstrates optimal stability when towing against waves,particularly when the towing direction aligns at a specific angle relative to the wave direction.In addition,a controlled increase in towing speed within a specific range effectively mitigates roll and pitch motions,which enhances the overall tow stability of the platform.Notably,compartment failure has an adverse effect on the towing stability,particularly in aft compartments.Therefore,it requires careful consideration and attention in practical engineering scenarios. 展开更多
关键词 integrated wellhead platform TOWING air flotation numerical simulation compartments failure
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Enhanced removal of polystyrene nanoplastics by air flotation modified by dodecyltrimethylammonium chloride:Performance and mechanism
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作者 Jinhui Xu Yanting Zhang +6 位作者 Kecheng Wen Xinyu Wang Zhiwei Yang Yuan Huang Guozhong Zheng Lupeng Huang Jing Zhang 《Chinese Chemical Letters》 2025年第5期588-594,共7页
Nanoplastics exhibit greater environmental biotoxicity than microplastics and can be ingested by humans through major routes such as tap water,bottled water and other drinking water.Nanoplastics present a challenge fo... Nanoplastics exhibit greater environmental biotoxicity than microplastics and can be ingested by humans through major routes such as tap water,bottled water and other drinking water.Nanoplastics present a challenge for air flotation due to their minute particle size,negative surface potential,and similar density to water.This study employed dodecyltrimethylammonium chloride(DTAC)as a modifier to improve conventional air flotation,which significantly enhanced the removal of polystyrene nanoplastics(PSNPs).Conventional air flotation removed only 3.09%of PSNPs,while air flotation modified by dodecyltrimethylammonium chloride(DTAC-modified air flotation)increased the removal of PSNPs to 98.05%.The analysis of the DTAC-modified air flotation mechanism was conducted using a combination of instruments,including a zeta potential analyzer,contact angle meter,laser particle size meter,high definition camera,scanning electron microscope(SEM),energy dispersive spectrometer(EDS)and Fourier transform infrared spectrometer(FTIR).The results indicated that the incorporation of DTAC reversed the electrostatic repulsion between bubbles and PSNPs to electrostatic attraction,significantly enhancing the hydrophobic force in the system.This,in turn,improved the collision adhesion effect between bubbles and PSNPs.The experimental results indicated that even when the flotation time was reduced to 7min,the DTACmodified air flotation still achieved a high removal rate of 96.26%.Furthermore,changes in aeration,pH,and ionic strength did not significantly affect the performance of the modified air flotation for the removal of PSNPs.The removal rate of PSNPs in all three water bodies exceeded 95%.The DTAC-modified air flotation has excellent resistance to interference from complex conditions and shows great potential for practical application. 展开更多
关键词 Polystyrene nanoplastics Dodecyltrimethylammonium chloride Modified air flotation MECHANISM Effectiveness and stability
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Bubble performance of a novel dissolved air flotation(DAF) unit
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作者 CHENFu-tai PENGFeng-xian +1 位作者 WUXiao-qing LUANZhao-kun 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2004年第1期104-107,共4页
ES-DAF, a novel DAF with low cost, high reliability and easy controllability, was studied. Without a costly air saturator, ES-DAF consists of an ejector and a static mixer between the pressure side and suction side of... ES-DAF, a novel DAF with low cost, high reliability and easy controllability, was studied. Without a costly air saturator, ES-DAF consists of an ejector and a static mixer between the pressure side and suction side of the recycle rotary pump. The bubble size distribution in this novel unit was studied in detail by using a newly developed CCD imagination through a microscope. Compared with M-DAF under the same saturation pressure, ES-DAF can produce smaller bubble size and higher bubble volume concentration, especially in lower pressure. In addition, the bubble size decreases with the increase of reflux ratio or decrease of superficial air-water ratio. These results suggested that smaller bubbles will be formed when the initial number of nucleation sites increases by enhancing the turbulence intensity in the saturation system. 展开更多
关键词 dissolved air flotation(DAF) bubble size distribution air saturation system CCD imagination
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Strategy for Controlling the Level in a Dissolved Air Flotation Chamber
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作者 Rodrigo Almeida Galdino Alex Elton de Moura +1 位作者 Valdemir Alexandre dos Santos Leonie Asfora Sarubbo 《Journal of Chemistry and Chemical Engineering》 2015年第5期344-352,共9页
The aim of the present study was to implant an efficient strategy for controlling the level of the effluent-oily foam interface in a DAF (dissolved air flotation) chamber of a pilot-scale prototype. DAF has been suc... The aim of the present study was to implant an efficient strategy for controlling the level of the effluent-oily foam interface in a DAF (dissolved air flotation) chamber of a pilot-scale prototype. DAF has been successfully used in the treatment of oily water, which is one of the main environmental problems in different industrial facilities. Along with important operational parameters, such as microbubble size and flow rate, the control strategy for the automation of a DAF chamber may be an important tool for increasing efficiency. Controlling the level was the strategy chosen to enhance the separation efficiency in a pilot-scale DAF prototype, with monitoring performed using a computational program in LabVIEW (laboratory virtual instrument engineering workbench). The findings demonstrate that it is possible to maintain the level of the fluid at a reference value established by the operator using the software program through the application of classic proportional integral derivative controllers. Using this control tool, the efficiency of water-oil separation in the pilot flotation chamber prototype was increased to nearly 98%. 展开更多
关键词 Dissolved air flotation level control LABVIEW proportional integral derivative liquid-liquid separation.
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Surface characteristics of microalgae and their effects on harvesting performance by air flotation 被引量:4
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作者 Wen Hao Li Yanpeng +3 位作者 Shen Zhou Ren Xiangying Zhang Wenjun Liu Jun 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2017年第1期125-133,共9页
Flotation is considered as an effective and energy efficient method for harvesting microalgae.However,the interaction mechanism between bubble-algae cell and cell-cell interfacial boundaries in microalgae flotation is... Flotation is considered as an effective and energy efficient method for harvesting microalgae.However,the interaction mechanism between bubble-algae cell and cell-cell interfacial boundaries in microalgae flotation is not completely clear.To better understand the effects of surface characteristics on microalgae flotation performance,the hydrophobicity and the zeta potential of two different microalgae species were quantified based on experimental measurements and the extended DLVO(Derjagin–Landau–Verwey–Overbeek)theory.Flotation experiments were then carried out and the effects of surface characteristics on microalgae flotation performance were analyzed.Algae Chlorella vulgaris and Anabaena vasriabilis show naturally hydrophilic and hydrophobic properties,respectively.The addition of a cationic surfactant(C16TAB)can modify hydrophilic microalgae cells into hydrophobic and further Chlorella hydrophobicity is enhanced with increased C16TAB concentrations.The zeta potentials of both algae strains are negative in the tested pH range.Compared with Chlorella vulgaris,the magnitude of zeta potential of Anabaena vasriabilis is found larger at the same pH,resulting in a more dispersed distribution in the suspension.In addition,flotation experiments demonstrated that microalgae hydrophobicity and zeta potential have significant impacts on the harvesting efficiency and concentration factor.The hydrophobic attraction is found to play a more important role in determining the harvesting performance than electrostatic repulsion between the interacting surfaces,especially for hydrophobicity algae in the present study.Finally,the highest flotation efficiency and the highest concentration factor could not be concurrently obtained for both algae strains,suggesting that optimized flotation conditions should be selected as a compromise. 展开更多
关键词 MICROALGAE air flotation harvesting performance surface characteristics zeta potential HYDROPHOBICITY
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Feasibility of bubble surface modification for natural organic matter removal from river water using dissolved air flotation 被引量:1
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作者 Yulong Shi Jiaxuan Yang +1 位作者 Jun Ma Congwei Luo 《Frontiers of Environmental Science & Engineering》 SCIE EI CAS CSCD 2017年第6期89-98,共10页
A novel, functionalized bubble surface can be obtained in dissolved air flotation (DAF) by dosing chemicals in the saturator. In this study, different cationic chemicals were used as bubble surface modifiers, and th... A novel, functionalized bubble surface can be obtained in dissolved air flotation (DAF) by dosing chemicals in the saturator. In this study, different cationic chemicals were used as bubble surface modifiers, and their effects on natural organic matter (NOM) removal from river water were investigated. NOM in the samples was fractionated based on molecular weight and hydrophobicity. The disinfection byproduct formation potentials of each fraction and their removal efficiencies were also evaluated. The results showed that chitosan was the most promising bubble modifier compared with a surfactant and a synthetic polymer. Tiny bubbles in the OAF pump system facilitated the adsorption of chitosan onto microbubble surfaces. The hydrophobic NOM fraction was preferentially removed by chitosan-modified bubbles. Decreasing the recycle water pH from 7.0 to 5.5 improved the removal of hydrophilic NOM with low molecular weight. Likewise, hydrophilic organic compounds gave high dihaloacetic acid yields in raw water. An enhanced reduction of haloacetic acid precursors was obtained with recycle water at pH values of 5.5 and 4.0. The experimental results indicate that NOM fractions may interact with bubbles through different mechanisms. Positive bubble modification provides an alternative approach for OAF to enhance NOM removal. 展开更多
关键词 Bubble surface modification Chitosan Disinfection by-product Dissolved air flotation Organic fraction
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Treatment of Wastewater Containing Heavy Metals Using Dissolved Air Released Flotation Column
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作者 LI Xiao-bing LIU Jiong-tian WANG Yong-tian CAO Yi-jun 《Journal of China University of Mining and Technology》 EI 2005年第3期187-191,共5页
A new type of dissolved air released flotation column is developed to treat wastewater containing Cr(Ⅵ) based on advantages of both dissolved air floatation and column floatation. By using a column with a diameter ... A new type of dissolved air released flotation column is developed to treat wastewater containing Cr(Ⅵ) based on advantages of both dissolved air floatation and column floatation. By using a column with a diameter of 50 mm and a specially made dissolved air releaser, micro-bubbles inside the column can be formed. N2H4H2O was used as reductant, AlCl3 as flocculant, C12H25SO3Na(SDS) as surfactant in the experiment. The effects of pH of wastewater, pressure of dissolved air, ratio of return water, and concentration of flocculant and surfactant on the removal efficiency are studied. The results show that the efficiency of dissolved air released flotation column is much higher than that of other approaches after the operation parameters are optimized, with the reduction ratio of Cr(Ⅵ ) in wastewater reaching 98%. So this technique can be widely used in wastewater treatment 展开更多
关键词 dissolved air released flotation column wastewater treatment heavy metal
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Experimental Study on Towing Characteristics of Composite Bucket Wellhead Platform
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作者 ZHANG Pu-yang LIU Ying-fei +2 位作者 LE Cong-huan DING Hong-yan BAI Yu 《China Ocean Engineering》 SCIE EI CSCD 2024年第3期531-542,共12页
With the rapid development of large-scale development of marginal oilfields in China,simple wellhead platforms that are simple in structure and easy to install have become an inevitable choice in the process of oilfie... With the rapid development of large-scale development of marginal oilfields in China,simple wellhead platforms that are simple in structure and easy to install have become an inevitable choice in the process of oilfield development.However,traditional simple wellhead platforms are often discarded after a single use.In pursuit of a more costeffective approach to developing marginal oilfields,this paper proposes a new offshore oil field development facility—an integrated bucket foundation for wellhead platform.To verify the safety of its towing behavior and obtain the dynamic response characteristics of the structure,this paper takes a bucket integrated bucket foundation for wellhead platform with a diameter of 40 m as the research object.By combining physical model tests and numerical simulations,it analyzes the static stability and dynamic response characteristics of the structure during towing,complete with the effects of the draft,wave height,wave period,and towing point height,which produce the dynamic responses of the structure under different influence factors,such as roll angle,pitch angle,heave acceleration and towing force as well as the sensibility to transport variables.The results show that the integrated bucket foundation for wellhead platform is capable of self-floating towing,and its movement is affected by the local environment,which will provide a reference for actual projects. 展开更多
关键词 composite bucket foundation wellhead platform air flotation towing model test
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Pre-oxidation enhanced cyanobacteria removal in drinking water treatment: A review 被引量:7
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作者 Jing Qi Baiwen Ma +3 位作者 Shiyu Miao Ruiping Liu Chengzhi Hu Jiuhui Qu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2021年第12期160-168,共9页
Cyanobacterial bloom has many adverse effects on source water quality and drinking water production. The traditional water treatment process can hardly achieve satisfactory removal of algae cells. This review examines... Cyanobacterial bloom has many adverse effects on source water quality and drinking water production. The traditional water treatment process can hardly achieve satisfactory removal of algae cells. This review examines the impact of pre-oxidation on the removal of cyanobacteria by solid-liquid separation processes. It was reported that the introduction of chemical oxidants such as chlorine, potassium permanganate, and ozone in algae-laden water pretreatment could improve algae removal by the subsequent solid-liquid separation processes. However, over dosed oxidants can result in more serious water quality risks due to significant algae cell lysis and undesirable intracellular organic matter release. It was suggested that moderate pre-oxidation may enhance the removal of cyanobacteria without damaging algae cells. In this article, effects of moderate pretreatment on the solid-liquid separation processes(sedimentation, dissolved air flotation, and membrane filtration) are reviewed. 展开更多
关键词 Cyanobacterial bloom PRE-OXIDATION SEDIMENTATION Dissolved air flotation Membrane filtration
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Liquid-phase hydrodechlorination of trichloroethylene driven by nascent H_(2)under an open system:Hydrogenation activity,solvent effect and sulfur poisoning
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作者 Weilai Wang Fan Zhang +3 位作者 Yunfei Zhang Lei Xu Yuansheng Pei Junfeng Niu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2021年第10期96-106,共11页
Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene(TCE).In this work,the liquid-phase hydrogenation of TCE by Raney Ni(R-Ni)and Pd/C under an open syste... Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene(TCE).In this work,the liquid-phase hydrogenation of TCE by Raney Ni(R-Ni)and Pd/C under an open system have been studied,in which nascent H_(2)(Nas-H_(2))generated in situ from the cathode acted as a hydrogen source.Experimental results showed that TCE was completely eliminate from the solution through the synergistic effects of hydrodechlorination and air flotation due to the formation of continuous micro/nano-sized Nas-H_(2)bubbles from the cathode.Furthermore,the effects of inorganic anions and organic solvents on R-Ni and Pd/C hydrogenation activity were investigated,respectively.The results showed that NO_(3)^(-) and acetonitrile can form a competitive reaction with TCE;Sulfur with lone-pair electrons will cause irreversible poisoning to these two catalysts,and have a stronger inhibitory effect on Pd/C.This work helps to realize the separation of volatile halogenated compounds from water environment and provides certain data support for the choice of catalyst in the actual liquid-phase hydrogenation system. 展开更多
关键词 Nascent H_(2) HYDROGENATION air flotation TRICHLOROETHYLENE Sulfur poisoning
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Research on DAF-BAF process in textile wastewater treatment
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作者 李玉华 孙希兵 郭健男 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2004年第6期610-613,共4页
This experiment researches textile wastewater, adopts a BAF process that has developed quickly in recent years, and makes use of dissolved air flotation as a pretreatment process that can effectively make up for BAF’... This experiment researches textile wastewater, adopts a BAF process that has developed quickly in recent years, and makes use of dissolved air flotation as a pretreatment process that can effectively make up for BAF’s lack of removing Chromaticity color. Performance effect, influencing factor, control condition have been reviewed and parameters of correlation have been analyzed in this experiment. The experiment and actual performance results indicate that this process is an effective way to remove the COD, suspended solid and colority with the value of 100 mg/L, 50 mg/L and 70 multiple respectively. The effluent meets the requirement of the standards of national sewage discharge. This process features a simple schematic, small location, continuous, reliable performance, strong shock and loading resistance and easy operation. Experimental data can provide scientific evidence and technical support for engineering practice of this process. 展开更多
关键词 textile wastewater biological aerated filter dissolved air flotation chromaticity color
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