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Time-resolved characteristics of a nanosecond pulsed multi-hollow needle plate packed bed dielectric barrier discharge
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作者 秦亮 李瑶 +6 位作者 郭浩 姜楠 宋颖 贾锐 周雄峰 袁皓 杨德正 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第7期48-57,共10页
In this paper,self-designed multi-hollow needle electrodes are used as a high-voltage electrode in a packed bed dielectric barrier discharge reactor to facilitate fast gas flow through the active discharge area and ac... In this paper,self-designed multi-hollow needle electrodes are used as a high-voltage electrode in a packed bed dielectric barrier discharge reactor to facilitate fast gas flow through the active discharge area and achieve large-volume stable discharge.The dynamic characteristics of the plasma,the generated active species,and the energy transfer mechanisms in both positive discharge(PD)and negative discharge(ND)are investigated by using fast-exposure intensified charge coupled device(ICCD)images and time-resolved optical emission spectra.The experimental results show that the discharge intensity,number of discharge channels,and discharge volume are obviously enhanced when the multi-needle electrode is replaced by a multihollow needle electrode.During a single voltage pulse period,PD mainly develops in a streamer mode,which results in a stronger discharge current,luminous intensity,and E/N compared with the diffuse mode observed in ND.In PD,as the gap between dielectric beads changes from 0 to250μm,the discharge between the dielectric bead gap changes from a partial discharge to a standing filamentary micro-discharge,which allows the plasma to leave the local area and is conducive to the propagation of surface streamers.In ND,the discharge only appears as a diffusionlike mode between the gap of dielectric beads,regardless of whether there is a discharge gap.Moreover,the generation of excited states N_(2)^(+)(B^(2)∑_(u)^(+))and N2(C^(3)Π_(u))is mainly observed in PD,which is attributed to the higher E/N in PD than that in ND.However,the generation of the OH(A^(2)∑^(+))radical in ND is higher than in PD.It is not directly dominated by E/N,but mainly by the resonant energy transfer process between metastable N_(2)(A^(3)∑_(u)^(+))and OH(X^(2)Π).Furthermore,both PD and ND demonstrate obvious energy relaxation processes of electron-to-vibration and vibration-to-vibration,and no vibration-to-rotation energy relaxation process is observed. 展开更多
关键词 packed bed reactor multi-hollow needle electrodes positive and negative discharges optical emission spectra time-resolved images
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Preparation of Pd/c-Al_(2)O_(3)/nickel foam monolithic catalyst and its performance for selective hydrogenation in a rotating packed bed reactor 被引量:1
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作者 Hai-Long Liao Bao-Ju Wang +4 位作者 Ya-Zhao Liu Yong Luo Jie-Xin Wang Guang-Wen Chu Jian-Feng Chen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2022年第1期311-319,共9页
Selective hydrogenation plays an important role in chemical industries,yet its selectivity is usually limited by the mass transfer.In this work,the enhanced hydrogenation selectivity was achieved in a rotating packed ... Selective hydrogenation plays an important role in chemical industries,yet its selectivity is usually limited by the mass transfer.In this work,the enhanced hydrogenation selectivity was achieved in a rotating packed bed(RPB)reactor with excellent mass transfer efficiency.Aiming to be used under the centrifugal filed,a monolithic catalyst Pd/c-Al_(2)O_(3)/nickel foam suiting for the shape and size of the rotor of RPB reactor was prepared by the electrophoretic deposition method.The mechanical strength of the catalyst can meet the requirement of high centrifugal force in the RPB.The hydrogenation selectivity in the RPB reactor using the 3-methyl-1-pentyn-3-ol hydrogenation system was 3–8 times higher than that in a stirred tank reactor under similar conditions.This work proves the feasibility of intensifying the selectivity of hydrogenation process in the RPB reactor. 展开更多
关键词 Monolithic catalyst Rotating packed bed reactor HYDROGENATION SELECTIVITY
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Reaction Selectivity Improvement for Reduction of Nitrobenzene in a Packed-Bed Electrode Reactor under Periodic-Current Control 被引量:1
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作者 丁平 杨晓勤 袁渭康 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1998年第4期44-51,共8页
Rectangular wave current control of the electrochemical reduction of nitrobenzene im-proves the selectivity for p-aminophenol(PAP) compared to direct current(d.c.) control at thesame average current density in a flow-... Rectangular wave current control of the electrochemical reduction of nitrobenzene im-proves the selectivity for p-aminophenol(PAP) compared to direct current(d.c.) control at thesame average current density in a flow-by packed-bed reactor.Optimal increase in PAP selectivitycan be obtained at about a frequency of 50Hz and a duty cycle of 0.2.A mathematical model isset up to incorporate the effects of mass transfer,hydrogen evolution and double layer charging,and is solved using the Duhamel’s superposition principle and the modified Crank-Nicolson methodwith the upwind scheme.The conventional d.c.control cases are also calculated for comparison.Calculations can be applied to predict the reaction results under periodic current and d.c.control,but both display the same trends compared to experimental data. 展开更多
关键词 NITROBENZENE ELECTROREDUCTION packed-bed ELECTRODE reactor PERIODIC current control
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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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Enhancing the Removal of Organic Matter and Nutrient from Wastewater by Using the Packed Bed Biological Reactor
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作者 Moayyed Shawaqfah 《Journal of Environmental Protection》 2014年第4期232-239,共8页
Packed Bed biological Reactor (PBR) system has the potential to offer an effective and low-cost technology for upgrading the conventional wastewater treatment systems. The objective of this study was to evaluate the p... Packed Bed biological Reactor (PBR) system has the potential to offer an effective and low-cost technology for upgrading the conventional wastewater treatment systems. The objective of this study was to evaluate the performance of PBR in removing the organic matter and nutrient from different types of wastewater (primary treatment effluent and secondary treatment effluent (exit of biological unit)). The experiments were carried out in two laboratory-sized reactors with 4 L in volume made of Plexiglas. The reactor was filled with PET packing and the reactor was kept in a temperature-controlled water bath at 20°C. Wastewater samples used in this experiment were collected from Wadi Al-Arab wastewater treatment plant in Irbid, Jordan. The concentrations of COD, TN, and TP were 280 mg/l, 41.74 mg-N/l and 9 mg/l, respectively in the primary effluents. Also, the concentrations of COD, TN, and TP were 58 mg/l, 61.55 mg-N/l and 33 mg/l, respectively in the secondary effluents. The removal efficiencies of COD, TN, and TP were 52%, 52% and 79% respectively when using the primary effluent as an influent to the reactor. On the other hand, when using the secondary effluent as an influent to the reactor, the removal efficiencies of COD, TN, and TP were 30%, 77%, and 81%, respectively. Thus, this technique could be used as a posttreatment step for conventional biological wastewater treatment. 展开更多
关键词 WASTEWATER Treatment NUTRIENT REMOVAL packed bed reactor
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Determination of External Mass Transfer Model for Hydrolysis of Jatropha Oil Using Immobilized Lipase in Recirculated Packed-Bed Reactor
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作者 Chong-Wan Cheng Rahmath Abdulla +1 位作者 Rao. Rampally Sridhar Pogaku Ravindra 《Advances in Chemical Engineering and Science》 2011年第4期289-298,共10页
In this study, a simple and effective technique for establishing an external mass transfer model in a recirculated packed-bed batch reactor (RPBBR) with an immobilized lipase enzyme and Jatropha oil system is presente... In this study, a simple and effective technique for establishing an external mass transfer model in a recirculated packed-bed batch reactor (RPBBR) with an immobilized lipase enzyme and Jatropha oil system is presented. The external mass transfer effect can be represented with a model in the form of Colburn factor JD = K Re-(1–n). The value of K and n were derived from experimental data at different mass flow rates.The experiment shows an average increment of 1.51% FFA for calcium alginate and 1.62% FFA for carrageenan after the hydrolysis took place. Based on different biopolymer material used in immobilized beads, JD = 1.674 Re-0.4 for calcium alginate and JD = 1.881 Re-0.3 for k-carrageenan were found to be adequate to predict the experimental data for external mass transfer in the reactor in the Reynolds number range of 0.2 to 1.2. The purposed model can be used for the design of industrial bioreactor and scale up. Besides, the external mass transfer coefficients for the hydrolysis of Jatropha oil reaction and the entrapment efficiency for the two biopolymer materials used were also investigated. 展开更多
关键词 PSEUDOMONAS Cepacialipase JATROPHA Curcas L. Oil CARRAGEENAN Calcium ALGINATE HYDROLYSIS packed bed reactor Immobilized Enzyme EXTERNAL Film Diffusion
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Numerical simulation of packed-bed reactor for oxidative coupling of methane
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作者 Zhao Zhang Ziqi Guo Shengfu Ji 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2015年第1期23-30,共8页
A three-dimensional geometric model of the oxidative coupling of methane (OCM) packed-bed reactor loaded with Na2WO4-Mn/SiO2 partic- ulate catalyst was set up, and an improved Stansch kinetic model was established t... A three-dimensional geometric model of the oxidative coupling of methane (OCM) packed-bed reactor loaded with Na2WO4-Mn/SiO2 partic- ulate catalyst was set up, and an improved Stansch kinetic model was established to calculate the OCM reactions using the computational fluid dynamics method and Fluent software. The simulation conditions were completely the same with the experimental conditions that the volume velocity of the reactant was 80 mL/min under standard state, the ratio of CH4/O2 was 3, the temperature and pressure were 800 ℃ and 1 atm, respectively. The contour of the characteristics parameters in the catalyst bed was analyzed, such as the species mass fractions, temperature, the heat flux on side wall surface, pressure, fluid density and velocity. The results showed that the calculated values matched well with the experimental values on the conversion of CH4 and the selectivity to products (C2H6, C2H4, CO2, CO) in the reactor outlet with an error range of 4-2%. The mass fractions of CH4 and O2 decreased from 0.6 and 0.4 in the catalyst bed inlet to 0.436 and 0.142 in the outlet, where the mass fractions of C2H6, C2H4, CO and CO2 were 0.035, 0.061, 0.032 and 0.106, respectively. Due to the existence of laminar boundary layer, the contours of each component bent upwards in the vicinity of the boundary layer. This OCM reaction was volume increase reaction and the total moles of products were greater than those of reactants. The flow field in the catalyst bed maintained constant temperature and pressure. The fluid density decreased gradually from 2.28 kg/m3 in the inlet of the catalyst bed to 2.22 kg/m3 in the outlet of the catalyst bed, while the velocity increased from 0.108 m/s to 0.115 m/s. 展开更多
关键词 oxidative coupling of methane packed-bed reactor computational fluid dynamics numerical simulation
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Comparing two IBM implementations for the simulation of uniform packed beds 被引量:2
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作者 Christian Gorges Maximilian Brommer +5 位作者 Christin Velten Siegmar Wirtz Enric Illana Mahiques Viktor Scherer Katharina Zahringer Berend van Wachem 《Particuology》 SCIE EI CAS CSCD 2024年第3期1-12,共12页
Nowadays,the design of fixed packed bed reactors still relies on empirical correlations,which,especially for small tube to particle diameter ratios,are mostly too inaccurate because of the presence of wall effects.The... Nowadays,the design of fixed packed bed reactors still relies on empirical correlations,which,especially for small tube to particle diameter ratios,are mostly too inaccurate because of the presence of wall effects.Therefore,the simulation of fixed packed bed reactors plays an important role to predict and control the flow and process parameters in such,nowadays and in the future.Because of its straightforward applicability to non-uniform packings with particles of arbitrary shapes,the immersed boundary method(IBM)has advantages over other numerical methods and is used more and more frequently.This paper compares two approaches of IBMs for the simulation of fixed bed reactors with spherical shaped particles.The classic,smooth approach is compared to the straightforward to implement blocked-off method for velocity fields above the fixed bed for particle Reynolds numbers of 300 and 500.Results from experimental inline PIV-measurements of the reactor to be simulated serve as a basis for comparison.Very good agreement with the experiment is found for both simulation methodologies with higher resolutions,considering the more stable flow at a particle Reynolds number of 300.Differences in the different IBM approaches occurred for the more unsteady flow at a particle Reynolds number of 500.Compared to the blocked-off method,the smooth IBM reflects the formation of additional jets and recirculation zones better right above the bed,though increasing the fluid mesh resolution improves the accuracy of the blocked-off method.Overall,a more diffusive behaviour is found for the blocked-off simulations due to the stairstep representation,which is avoided by using interpolation stencils as in the smooth IBM.With higher mesh refinement in the blocked-off IBM this effect can be reduced,but this also increases the computational effort. 展开更多
关键词 Immersed boundary method packed bed reactor Uniform particle packing
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Experimental and numerical investigation to elucidate the fluid flow through packed beds with structured particle packings
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作者 Shirin Patil Christian Gorges +3 位作者 Joel Lòpez Bonilla Moritz Stelter Frank Beyrau Berend van Wachem 《Particuology》 SCIE EI CAS CSCD 2024年第6期218-237,共20页
The present paper presents an experimental and numerical investigation of the dispersion of the gaseous jet flow and co-flow for the simple unit cell(SUC)and body-centred cubic(BCC)configuration of particles in packed... The present paper presents an experimental and numerical investigation of the dispersion of the gaseous jet flow and co-flow for the simple unit cell(SUC)and body-centred cubic(BCC)configuration of particles in packed beds.The experimental setup is built in such a way that suitable and simplified boundary conditions are imposed for the corresponding numerical framework,so the simulations can be done under very similar conditions as the experiments.Accordingly,a porous plate is used for the co-flow to achieve the uniform velocity and the fully developed flow is ensured for the jet flow.The SUC and BCC particle beds consist of 3D-printed spheres,and the non-isotropy near the walls is mostly eliminated by placing half-spheres at the channel walls.The flow velocities are analysed directly at the exit of the particle bed for both beds over 36 pores for the SUC configuration and 60 pores for the BCC configuration,for particle Reynolds numbers of 200,300,and 400.Stereo particle image velocimetry is experimentally arranged in such a way that the velocities over the entire region at the exit of the packed bed are obtained instantaneously.The numerical method consists of a state-of-the-art immersed boundary method with adaptive mesh refinement.The paper presents the pore jet structure and velocity field exiting from each pore for the SUC and BCC packed particle beds.The numerical and experimental studies show a good agreement for the SUC configuration for all flow velocities.For the BCC configuration,some differences can be observed in the pore jet flow structure between the simulations and the experiments,but the general flow velocity distribution shows a good overall agreement.The axial velocity is generally higher for the pores located near the centre of the packed bed than for the pores near the wall.In addition,the axial velocities are observed to increase near the peripheral pores of the packed bed.This behaviour is predominant for the BCC configuration as compared to the SUC configuration.The velocities near the peripheral pores can become even higher than those at the central pores for the BCC configuration.It is shown that both the experiments as well as the simulations can be used to study the complex fluid structures inside a packed bed reactor. 展开更多
关键词 Uniform particle packing packed bed reactor Stereo particle image velocimetry Immersed boundary method
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Conversion enhancement of tubular fixed-bed reactor for Fischer-Tropsch synthesis using static mixer 被引量:2
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作者 Phavanee Narataruksa Sabaithip Tungkamani +6 位作者 Karn Pana-Suppamassadu Phongsak Keeratiwintakorn Siriluck Nivitchanyong Piyapong Hunpinyo Hussanai Sukkathanyawat Prayut Jiamrittiwong Visarut Nopparat 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2012年第4期435-444,共10页
Recently, Fischer-Tropsch synthesis (FTS) has become an interesting technology because of its potential role in producing biofuels via Biomass- to-Liquids (BTL) processes. In Fischer-Tropsch (FT) section, biomas... Recently, Fischer-Tropsch synthesis (FTS) has become an interesting technology because of its potential role in producing biofuels via Biomass- to-Liquids (BTL) processes. In Fischer-Tropsch (FT) section, biomass-derived syngas, mainly composed of a mixture of carbon monoxide (CO) and hydrogen (H2), is converted into various forms of hydrocarbon products over a catalyst at specified temperature and pressure. Fixed-bed reactors are typically used for these processes as conventional FT reactors. The fixed-bed or packed-bed type reactor has its drawbacks, which are heat transfer limitation, i.e. a hot spot problem involved highly exothermic characteristics of FT reaction, and mass transfer limitation due to the condensation of liquid hydrocarbon products occurred on catalyst surface. This work is initiated to develop a new chemical reactor design in which a better distribution of gaseous reactants and hydrocarbon products could be achieved, and led to higher throughput and conversion. The main goal of the research is the enhancement of a fixed-bed reactor, focusing on the application of KenicsTM static mixer insertion in the tubular packed-bed reactor. Two FTS experiments were carried out using two reactors i.e., with and without static mixer insertion within catalytic beds. The modeled syngas used was a mixed gas composed of H2/CO in 2 : 1 molar ratio that was fed at the rate of 30 mL(STP)·min^- 1 (GHSV ≈ 136 mL·gcat^-1 ·h^-1) into the fixed Ru supported aluminum catalyst bed of weight 13.3 g. The reaction was carried out at 180 ℃ and atmospheric pressure continuously for 36 h for both experiments. Both transient and steady-state conversions (in terms of time on stream) were reported. The results revealed that the steady-state CO conversion for the case using the static mixer was approximately 3.5 times higher than that of the case without static mixer. In both cases, the values of chain growth probability of hydrocarbon products (α) for Fischer-Tropsch synthesis were 0.92 and 0.89 for the case with and without static mixer, respectively. 展开更多
关键词 Fischer-Tropsch synthesis fixed-bed reactor packed-bed reactor static mixer
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Meta-analysis of CO_(2) conversion,energy efficiency,and other performance data of plasma-catalysis reactors with the open access PIONEER database 被引量:1
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作者 Antoine Salden Maik Budde +28 位作者 Carolina A.Garcia-Soto Omar Biondo Jairo Barauna Marzia Faedda Beatrice Musig ChloéFromentin Minh Nguyen-Quang Harry Philpott Golshid Hasrack Domenico Aceto Yuxiang Cai Federico Azzolina Jury Annemie Bogaerts Patrick Da Costa Richard Engeln María Elena Gálvez Timo Gans Tomas Garcia Vasco Guerra Carlos Henriques Monika Motak Maria Victoria Navarro Vasile I.Parvulescu Gerard Van Rooij Bogdan Samojeden Ana Sobota Paolo Tosi Xin Tu Olivier Guaitella 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第11期318-342,I0007,共26页
This paper brings the comparison of performances of CO_(2)conversion by plasma and plasma-assisted catalysis based on the data collected from literature in this field,organised in an open access online database.This t... This paper brings the comparison of performances of CO_(2)conversion by plasma and plasma-assisted catalysis based on the data collected from literature in this field,organised in an open access online database.This tool is open to all users to carry out their own analyses,but also to contributors who wish to add their data to the database in order to improve the relevance of the comparisons made,and ultimately to improve the efficiency of CO_(2)conversion by plasma-catalysis.The creation of this database and database user interface is motivated by the fact that plasma-catalysis is a fast-growing field for all CO_(2)conversion processes,be it methanation,dry reforming of methane,methanolisation,or others.As a result of this rapid increase,there is a need for a set of standard procedures to rigorously compare performances of different systems.However,this is currently not possible because the fundamental mechanisms of plasma-catalysis are still too poorly understood to define these standard procedures.Fortunately however,the accumulated data within the CO_(2)plasma-catalysis community has become large enough to warrant so-called“big data”studies more familiar in the fields of medicine and the social sciences.To enable comparisons between multiple data sets and make future research more effective,this work proposes the first database on CO_(2)conversion performances by plasma-catalysis open to the whole community.This database has been initiated in the framework of a H_(2)0_(2)0 European project and is called the“PIONEER Data Base”.The database gathers a large amount of CO_(2)conversion performance data such as conversion rate,energy efficiency,and selectivity for numerous plasma sources coupled with or without a catalyst.Each data set is associated with metadata describing the gas mixture,the plasma source,the nature of the catalyst,and the form of coupling with the plasma.Beyond the database itself,a data extraction tool with direct visualisation features or advanced filtering functionalities has been developed and is available online to the public.The simple and fast visualisation of the state of the art puts new results into context,identifies literal gaps in data,and consequently points towards promising research routes.More advanced data extraction illustrates the impact that the database can have in the understanding of plasma-catalyst coupling.Lessons learned from the review of a large amount of literature during the setup of the database lead to best practice advice to increase comparability between future CO_(2)plasma-catalytic studies.Finally,the community is strongly encouraged to contribute to the database not only to increase the visibility of their data but also the relevance of the comparisons allowed by this tool. 展开更多
关键词 Open-access database on plasma-catalysis experiment CO_(2) conversion PLASMA-CATALYSIS Carbon capture and utilisation(CCU) Energy efficiency Specific energy input Dielectric barrier discharge packed bed reactor METHANATION Dry reforming of methane
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高黏附性Pd/SiO_(2)/NF整体式催化剂的制备及加氢性能研究 被引量:1
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作者 韩宇 周乐 +4 位作者 张鑫 罗勇 孙宝昌 邹海魁 陈建峰 《化工学报》 EI CSCD 北大核心 2024年第4期1533-1542,共10页
旋转填充床反应器(RPB)中液体的高速冲刷和较强的离心力容易导致整体式催化剂的涂层和活性组分从基体表面脱落造成损失,限制了整体式催化剂在RPB反应器中的应用。因此,研究整体式催化剂涂层和活性组分的黏附性,以提升催化剂在RPB反应器... 旋转填充床反应器(RPB)中液体的高速冲刷和较强的离心力容易导致整体式催化剂的涂层和活性组分从基体表面脱落造成损失,限制了整体式催化剂在RPB反应器中的应用。因此,研究整体式催化剂涂层和活性组分的黏附性,以提升催化剂在RPB反应器中的催化活性和使用寿命具有重要意义。基于此,采用超重力喷涂法在泡沫镍(NF)基体表面负载氧化硅(SiO_(2))涂层,制备了具有高黏附性的Pd/SiO_(2(x))/NF整体式催化剂,通过超声振荡、BET、XRD、SEM和XPS等对整体式催化剂进行测试和分析。当RPB反应器的转速为1200 r/min时,整体式催化剂具有优异的黏附性能,涂层的脱落率为4%。以对硝基苯甲醚(PNA)催化加氢制备对氨基苯甲醚(PA)为探针反应,RPB反应器中Pd/SiO_(2(1200))/NF整体式催化剂具有较好的催化活性,180 min时PNA转化率为98.9%。本工作可为开发高黏附性的整体式催化剂提供新的途径。 展开更多
关键词 旋转填充床反应器 整体式催化剂 黏附性 催化加氢
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缠绕管式固定床反应器压降模拟与实验研究
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作者 牛硕磊 代玉强 +1 位作者 张伟健 徐琴琴 《化学工程》 CAS CSCD 北大核心 2024年第8期49-54,共6页
针对装填不同形状颗粒的缠绕管式固定床反应器,建立颗粒床层的物理模型,通过CFD-DEM(计算流体力学-离散元法)耦合模拟的方法,探究颗粒形状和缠绕管结构参数对床层空隙率、流体分布的影响,利用缠绕管式固定床反应器实验台对高雷诺数单相... 针对装填不同形状颗粒的缠绕管式固定床反应器,建立颗粒床层的物理模型,通过CFD-DEM(计算流体力学-离散元法)耦合模拟的方法,探究颗粒形状和缠绕管结构参数对床层空隙率、流体分布的影响,利用缠绕管式固定床反应器实验台对高雷诺数单相流动状态下的压降进行精确测量。结果表明:缠绕管螺距、层间距越小,床层空隙率越大,管径的变化对空隙率几乎没有影响。球形颗粒床层的流场分布差异较大,圆柱、棱柱颗粒床层流体分布均匀性依次改善。球形颗粒的CFD-DEM耦合模拟结果与实验结果吻合较好,但是非球形颗粒的模拟结果与实验结果存在一定误差。对多种压降预测公式进行对比,最后根据实验结果对常用的Ergun公式、Nemec-Levec公式进行常系数项修正来准确预测压降,研究结果可为缠绕管式固定床反应器设计和压降预测提供参考。 展开更多
关键词 缠绕管式固定床反应器 填充床 空隙率 数值模拟 压降
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A structured packed-bed reactor designed for exothermic hydrogenation of acetone 被引量:2
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作者 Yanjun Duan Min Xu +1 位作者 Xiaoming Zhou Xiulan Huai 《Particuology》 SCIE EI CAS CSCD 2014年第6期125-130,共6页
Fixed-bed reactors randomly packed with catalysts have many disadvantages that may adversely affect the desired chemical reaction.The increasingly used monolithic reactor,in contrast,has many operational advantages;ho... Fixed-bed reactors randomly packed with catalysts have many disadvantages that may adversely affect the desired chemical reaction.The increasingly used monolithic reactor,in contrast,has many operational advantages;however,for a kinetically-controlled reaction,it does not contain sufficient catalyst to sustain the reaction.To address the problems associated with both randomly packed-bed reactor and the monolithic reactor,a structured packed-bed reactor was proposed and mathematical models were built for randomly packed-bed reactor and structured packed-bed reactor.Their respective performances were compared when applied to the exothermic reaction of the isopropanol-acetone-hydrogen chemical heat pump system.The results showed that the structured packed-bed reactor performed better in terms of pressure drop and heat transfer capacity,and had a lower radial temperature gradient,indicating that this reactor had a higher effective heat conductivity.Isopropanol on the catalyst particle surfaces was more concentrated near the tube wall because a wall effect existed in the boundary layer around the particle-wall contact points. 展开更多
关键词 Chemical heat pump Structured packed-bed reactor Acetone hydrogenation CFD simulation
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A Comparative Study on Heat Transfer Performance of Typical Petrochemical Reactors 被引量:1
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作者 Li Yuxin 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2016年第4期61-70,共10页
The performance of heat transfer is a key issue for reactor design in petrochemical industry. Since the heat transfer in reactors is a complicated process and depends on multiple parameters, the evaluation of the heat... The performance of heat transfer is a key issue for reactor design in petrochemical industry. Since the heat transfer in reactors is a complicated process and depends on multiple parameters, the evaluation of the heat transfer performance is usually challenging, and few previous studies gave an overall view of heat exchange performance of different types of reactors. In this review, heat transfer coefficients of two types of petrochemical reactors, including the packed bed and the fluidized bed, were systematically analyzed and compared based on a number of reported correlations. The relationship between heat transfer coefficients and fluid flow velocity in different reactors has been well established, which clearly demonstrates the varying range of their heat transfer coefficients. Heat transfer coefficients of gas-phase packed bed can exceed 200 W/m^2·K, rather than the suggested values(17—89 W/m^2·K) mentioned in the literature. The fluidized bed shows better performance for both two-phase and three-phase beds as compared to the packed bed. Systems with liquid phase also show better heat transfer performance than other phases because of the larger heat capacity of liquid. Thus the industrial three-phase fluidized beds have the best heat transfer performance with an overall heat transfer coefficient of greater than 1 000 W/m^2·K. The heat transfer results provided by this review can afford not only new insights into the heat transfer in typical reactors, but also the basis and guidelines for reactor design and selection. 展开更多
关键词 heat transfer packed bed fluidized bed loop reactor transfer coefficient
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Green and scalable electrochemical routes for cost‐effective mass production of MXenes for supercapacitor electrodes 被引量:2
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作者 Zimo Huang Jiadong Qin +9 位作者 Yuxuan Zhu Kelin He Hao Chen Hui Ying Hoh Munkhbayar Batmunkh Tania MBenedetti Qitao Zhang Chenliang Su Shanqing Zhang Yu Lin Zhong 《Carbon Energy》 SCIE EI CAS CSCD 2023年第10期13-24,共12页
One of the most unique properties of two-dimensional carbides and nitrides of transition metals(MXenes)is their excellent water dispersibility and yet possessing superior electrical conductivity but their industrial-s... One of the most unique properties of two-dimensional carbides and nitrides of transition metals(MXenes)is their excellent water dispersibility and yet possessing superior electrical conductivity but their industrial-scale application is limited by their costly chemical synthesis methods.In this work,the niche feature of MXenes was capitalized in the packed-bed electrochemical reactor to produce MXenes at an unprecedented reaction rate and yield with minimal chemical waste.A simple NH4F solution was employed as the green electrolyte,which could be used repeatedly without any loss in its efficacy.Surprisingly,both fluoride and ammonium were found to play critical roles in the electrochemical etching,functionalization,and expansion of the layered parent materials(MAXs)through which the liberation of ammonia gas was observed.The electrochemically produced MXenes with excellent conductivity,applied as supercapacitor electrodes,could deliver an ultrahigh volumetric capacity(1408 F cm^(−3))and a volumetric energy density(75.8 Wh L^(−1)).This revolutionary green,energy-efficient,and scalable electrochemical route will not only pave the way for industrial-scale production of MXenes but also open up a myriad of versatile electrochemical modifications for improved functional MXenes. 展开更多
关键词 packedbed electrochemical reactor electrochemical etching MXene SUPERCAPACITOR
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填充床反应器中固定化假单胞菌细胞连续制备L-瓜氨酸 被引量:6
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作者 郑璞 倪晔 +2 位作者 张文 钱嘉南 孙志浩 《食品与生物技术学报》 CAS CSCD 北大核心 2008年第5期33-38,共6页
对实验室筛选的产精氨酸脱亚胺酶的假单胞菌(Pseudomonassp.)进行了固定化,以及对固定化细胞转化L-精氨酸生产L-瓜氨酸进行了研究。比较4种不同固定化方法,确定卡拉胶包埋结合戊二醛后处理为假单胞菌的细胞固定化方法。固定化反应的最... 对实验室筛选的产精氨酸脱亚胺酶的假单胞菌(Pseudomonassp.)进行了固定化,以及对固定化细胞转化L-精氨酸生产L-瓜氨酸进行了研究。比较4种不同固定化方法,确定卡拉胶包埋结合戊二醛后处理为假单胞菌的细胞固定化方法。固定化反应的最适pH值为6.5,细胞固定化后细胞精氨酸脱亚胺酶的热稳定性增加。在50 mm×240 mm固定填充床反应器中,底物浓度为0.5 mol/L L-精氨酸盐酸盐,pH值6.5,温度37℃,稀释速率为0.147/h的条件下,连续运转54d,固定化细胞对底物的摩尔转化率在95%以上,平均生产强度0.010 8 g/(h.g)(每单位质量的固定化细胞每小时生产的瓜氨酸质量)。转化液经732阳离子树脂吸附,氨水洗脱,及浓缩、结晶,得到纯度为99%的L-瓜氨酸晶体,提取总收率约为87%。 展开更多
关键词 L-瓜氨酸 假单胞菌(Pseudo monassp.) 固定化细胞 填充床反应器
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固定床自养反硝化去除地下水中的硝酸盐氮 被引量:31
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作者 姜巍 曲久辉 +2 位作者 雷鹏举 刘锁祥 孟光辉 《中国环境科学》 EI CAS CSSCI CSCD 北大核心 2001年第2期133-136,共4页
研究了装填固体填料硫和石灰石的生物膜反应器对水中硝酸盐氮的去除.结果表明,基于电子供体硫的自养反硝化菌对水中的硝酸盐氮有很好的去除效果.停留时间超过3h,即反应器处理量小于5.2L/h,去除率可达80%以上.沿反应器高度,亚硝酸盐氮浓... 研究了装填固体填料硫和石灰石的生物膜反应器对水中硝酸盐氮的去除.结果表明,基于电子供体硫的自养反硝化菌对水中的硝酸盐氮有很好的去除效果.停留时间超过3h,即反应器处理量小于5.2L/h,去除率可达80%以上.沿反应器高度,亚硝酸盐氮浓度先增加后降低,硫酸根浓度增加,其增加量与氮的去除量呈化学计量比关系.pH值沿反应器高度降低.反应器运行5个月以来,运转良好,未发生阻塞现象. 展开更多
关键词 固定床 自养反硝化 硝酸盐氮 地下水污染
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固体碳源填充床反应器反硝化性能的研究 被引量:15
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作者 李军 徐影 +4 位作者 王秀玲 仇天雷 韩梅琳 毛哲 王旭明 《农业环境科学学报》 CAS CSCD 北大核心 2012年第6期1230-1235,共6页
为了优化固体碳源填充床反应器的运行条件,以PLA/PHBV颗粒为碳源和生物膜载体,研究了水力负荷与硝态氮负荷对反应器反硝化性能的影响,并用扫描电镜观察碳源表面生物膜的形态。结果表明,在进水硝态氮浓度为100mg·L-1,水力负荷为1.71... 为了优化固体碳源填充床反应器的运行条件,以PLA/PHBV颗粒为碳源和生物膜载体,研究了水力负荷与硝态氮负荷对反应器反硝化性能的影响,并用扫描电镜观察碳源表面生物膜的形态。结果表明,在进水硝态氮浓度为100mg·L-1,水力负荷为1.71~8.39m3·m-2·d-1时,反硝化速率呈现先增加后降低的趋势,最大值为40.53mg·L-1·h-1;随着水力负荷的提高,出水硝态氮浓度逐渐增加,而COD浓度逐渐降低;维持水力负荷在3.54m3·m-2·d-1以下,可保证反应器的出水满足我国饮用水标准对硝态氮与亚硝态氮浓度的要求;维持水力负荷为5.30m3·m-2·d-1,反应器的反硝化速率与进水硝态氮负荷线性相关(R2=0.937),而硝态氮负荷对出水的COD浓度未发生明显影响;维持进水硝态氮负荷不高于0.16kg·m-2·d-1,可保证反应器出水的硝态氮与亚硝态氮浓度满足国家标准。通过扫描电镜照片可以看出,PLA/PHBV颗粒表面的生物膜以球菌和杆菌为主,成簇定植在碳源颗粒表面。 展开更多
关键词 硝酸盐 反硝化 可生物降解聚合物 填充床反应器
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等离子体协同光催化去除模拟烟气中SO_2的实验研究 被引量:10
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作者 依成武 冷秋颖 +2 位作者 孙莉 储金宇 吴春笃 《环境工程学报》 CAS CSCD 北大核心 2007年第8期89-91,共3页
近年来,低温等离子体技术以及纳米TiO2光催化技术在烟气脱硫中的应用越来越引起人们的关注。利用填充床反应器将这2种技术有机地结合起来,进行了大量脱硫实验研究。研究结果表明,等离子体协同光催化去除烟气中的SO2与单独采用等离子体... 近年来,低温等离子体技术以及纳米TiO2光催化技术在烟气脱硫中的应用越来越引起人们的关注。利用填充床反应器将这2种技术有机地结合起来,进行了大量脱硫实验研究。研究结果表明,等离子体协同光催化去除烟气中的SO2与单独采用等离子体技术相比,其SO2的去除率可提高5%-20%。同时,探讨了等离子体协同TiO2光催化剂的脱硫机理,分别研究了外加电压、气体流量和SO2初始浓度等因素对脱硫效率的影响。实验结果表明,当SO2初始浓度为800mg/m^3,输入电压为17.5 kV,气体流量为0.2 m^3/h时,SO2脱除率可以达到77.6%。 展开更多
关键词 脱硫 等离子体 光催化 填充床反应器
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