Five different internals were designed,and their effects on phase holdup and backmixing were investigated in a gas–liquid concurrent upflow reactor where the spherical alumina packing particles of three diameters(3.0...Five different internals were designed,and their effects on phase holdup and backmixing were investigated in a gas–liquid concurrent upflow reactor where the spherical alumina packing particles of three diameters(3.0,4.5 and6.0 mm)were slightly expanded under the conditions of varied superficial gas velocities(6.77×10^(-2)-3.61×10^(-1) m·s^(-1))and superficial liquid velocities(9.47×10^(-4)-2.17×10^(-3) m·s^(-1)).The experimental results show that the gas holdup increases with the superficial gas velocity and particle size,opposite to the variational trend of liquid holdup.When an internal component is installed amid the upflow reactor,a higher gas holdup,a less liquid holdup and a larger Peclet number characterizing the weaker backmixing are obtained compared to those in the bed without internals under the same operating conditions.Additionally,the minimal backmixing is observed in the reactor equipped with the internals with a novel multi-step design.Finally,empirical correlations were proposed for estimating gas holdup,liquid holdup and Peclet number with the relative deviations within 11%,12%and 25%,respectively.展开更多
The vapor diffusion and transport resulting from steam generator tube rupture(SGTR)accidents are a major concern threatening lead-based reactor core safety.In this study,a high-parameter SGTR experimental platform and...The vapor diffusion and transport resulting from steam generator tube rupture(SGTR)accidents are a major concern threatening lead-based reactor core safety.In this study,a high-parameter SGTR experimental platform and the multi-phase multi-physics processes numerical simulation were developed to investigate the phase behavior and interaction mechanisms.This study revealed the interaction mechanisms of lead-bismuth liquid metal and water driven by flash vaporization,jet impingement boiling,and moderate boiling.The migration and evolution of the discrete phases(vapor-water mixture)were inferred from the temperature transient laws and a numerical simulation.The results revealed that the evolution of the discrete phases consists of three stages:cavity formation,flanking diffusion,and stable up-floating.The jet pressure significantly extended the disturbance period.Variations in the water temperature mainly affected the depressurization boiling process,altering the diffusion region of the discrete phases.The temperature of the liquid metal and the duration of the jet had a minimal impact on the behavior of the discrete phases.This study provides a crucial reference for constructing a complete picture of accident evolution.展开更多
A new chemiluminescence flow system has been developed for sequential determina-tion of benzoic acid based on the reaction of the compound with copper carbonate entrapped in a solid-phase reactor. It was found that t...A new chemiluminescence flow system has been developed for sequential determina-tion of benzoic acid based on the reaction of the compound with copper carbonate entrapped in a solid-phase reactor. It was found that the unsaturated complex of Cu(II) and benzoic acid (1:1) has strong catalytic effect on the luminol-H2O2 chemiluminescence reaction. The calibration graph is linear over the range of 0.025 ~ 60 g/mL of benzoic acid, with a relative standard deviation of less than 3.0 %, and the detection limit is 0.01礸穖L-1. The proposed method was applied to the determination of benzoic acid content in different pharmaceutical formulations.展开更多
Hursts rescaled range (R/S) analysis and Wolfs attractor reconstruction technique have been adopted to estimate the local fractal dimensions and the local largest Lyapunov exponents in terms of the time series pressur...Hursts rescaled range (R/S) analysis and Wolfs attractor reconstruction technique have been adopted to estimate the local fractal dimensions and the local largest Lyapunov exponents in terms of the time series pressure fluctuations obtained from a gas liquid solid three phase self aspirated reversed flow jet loop reactor,respectively.The results indicate that the local fractal dimensions and the local largest Lyapunov exponents in both the jet region and the tubular region inside the draft tube increase with the increase in the jet liquid flowrates and the solid loadings,the local fractal dimension profiles are similar to those of the largest Lyapunov exponent,the local largest lyapunov exponents are positive for all cases,and the flow behavior of such a reactor is chaotic.The local nonlinear characteristic parameters such as the local fractal dimension and the local largest Lyapunov exponent could be applied to further study the flow properties such as the flow regime transitions and flow structures of this three phase jet loop reactor.展开更多
A three-phase reactor mathematical model was set up to simulate and design a three-phase bubble column reactor for direct synthesis of dimethyl ether （DME） from syngas, considering both the influence of part inert c...A three-phase reactor mathematical model was set up to simulate and design a three-phase bubble column reactor for direct synthesis of dimethyl ether （DME） from syngas, considering both the influence of part inert carrier backmixing on transfer and the influence of catalyst grain sedimentation on reaction. On the basis of this model, the influences of the size and reaction conditions of a 100000 t/a DME reactor on capacity were investigated. The optimized size of the 10000 t/a DME synthesis reactor was proposed as follows： diameter 3.2 m, height 20 m, built-in 400 tube heat exchanger （Ф 38×2 mm）, and inert heat carrier paraffin oil 68 t and catalyst 34.46 t. Reaction temperature and pressure were important factors influencing the reaction conversion for different size reactors. Under the condition of uniform catalyst concentration distribution, higher pressure and temperature were proposed to achieve a higher production capacity of DME. The best ratio of fresh syngas for DME synthesis was 2.04.展开更多
A two-phase anaerobic reactor fed with glucose substrate（3 g chemical oxygen demand（COD）/L） was used to investigate the effects of toxic metals on the degradation of organics and the soluble microbial product（SMP...A two-phase anaerobic reactor fed with glucose substrate（3 g chemical oxygen demand（COD）/L） was used to investigate the effects of toxic metals on the degradation of organics and the soluble microbial product（SMP） formation. Low concentrations of Ni（II）（5 and10 mg/L） promoted the acid phase, whereas high concentrations（15, 20, and 25 mg/L）exhibited an inhibitory effect on, but did not alter the fermentative method, which mainly involved the fermentation of propionic acid. The methanogenic microorganism exhibited a strong capability adapting constantly increased Ni（II） levels. The acid phase was an accumulation stage of SMP. In the absence of Ni（II）, the high-molecular-weight material in the effluent SMP mainly contained polysaccharide, tryptophan, and casein. Methanogens metabolized most of the polysaccharide, the whole tryptophan content, and part of the casein, leading to the presence of humic acid and protein in effluent. After Ni（II） dosage, the protein and polysaccharide of the acid phase increased, and tryptophan changed, while casein remained stable. More protein than polysaccharide was produced, suggesting the prominent function of protein when addressing the negative effect of toxic metals. The analysis of DNA confirmed the change of bacterial activity.展开更多
The synthesis of dipeptide AcPheLeuNH2 catalyzed by immobilized pancreatic lipase was carried out in a two- liquid-phase hollow-fiber membrane reactor, operated in a batch mode. Kinetic properties of free and immobili...The synthesis of dipeptide AcPheLeuNH2 catalyzed by immobilized pancreatic lipase was carried out in a two- liquid-phase hollow-fiber membrane reactor, operated in a batch mode. Kinetic properties of free and immobilized enzyme, partition behavior between aqueous buffer phase and organic solvent phase, and effective diffusion coefficients of substrates and products through the membrane were investigated respectively. Based on the preliminary experimental results, the performance of the enzyme membrane reactor, which is evaluated by the purity and the yield, is discussed.展开更多
By means of cavity-assisted photon interference, a simple scheme is proposed to implement a symmetric economical phase-covariant quantum cloning machine of two remote qubits, with each in a separate cavity. With our p...By means of cavity-assisted photon interference, a simple scheme is proposed to implement a symmetric economical phase-covariant quantum cloning machine of two remote qubits, with each in a separate cavity. With our present scheme, a high-fidelity cloning machine is realized. Our scheme may be quite useful in terms of distributed quantum information processing.展开更多
Riser reactor is a key unit in the Fluid Catalytic Cracking (FCC), and it has important influences on increasing the yield coefficient of gas and oil. In this paper, the behaviors of gas-solid two-phase flow in the tr...Riser reactor is a key unit in the Fluid Catalytic Cracking (FCC), and it has important influences on increasing the yield coefficient of gas and oil. In this paper, the behaviors of gas-solid two-phase flow in the traditional y-type riser reactor are investigated by numerical simulation. The calculated particle concentration distribution is in good agreement with the experimental data, which verified the advanced models and calculating methods. The non-uniform distribution, such as core-annulus flow, may result in the unreasonable matching relationship of catalyst-to-oil ratio. An optimized riser with cuneal internals is proposed and the comparison of two different structures of riser reactor is presented. The comparison results show that the cuneal internals in the riser both can block effectively the slip down of the particles near wall region and weaken core-annulus flow structure due to the redistribution of particles. The results also prove that the particle concentration distribution becomes uniform along the axial and radial direction in the optimized riser by adding cuneal internals, which would be benefits for the catalytic cracking reactions.展开更多
Some kinds of break in the reactor coolant system may cause the coolant to exit rapidly from the failure site,which leads to the loss of coolant accident(LOCA).In this paper,a stress analysis of an AP1000 reactor cont...Some kinds of break in the reactor coolant system may cause the coolant to exit rapidly from the failure site,which leads to the loss of coolant accident(LOCA).In this paper,a stress analysis of an AP1000 reactor containment is performed in an LOCA,with the passive containment cooling system(PCCS) being available and not available for cooling the wall's containment.The variations in the mechanical properties of the wall's containment,including elastic modulus,strength,and stress,are analyzed using the ABAQUS code.A general two-phase model is applied for modeling thermal-hydraulic behavior inside the containment.Obtained pressure and temperature from thermal-hydraulic models are considered as boundary conditions of the ABAQUS code to obtain distributions of temperature and stress across steel shell of the containment in the accident.The results indicate that if the PCCS fails,the peak pressure inside the containment exceeds the design value.However,the stress would still be lower than the yield stress value,and no risk would threaten the integrity of the containment.展开更多
基金Supported by the National Key Research and Development Program(2016YFB0301701)the National Natural Science Foundation of China(21776283,21427814)+1 种基金Key Research Program of Frontier Sciences of CAS(QYZDJ-SSW-JSC030)the Instrument Developing Project of Chinese Academy of Sciences(YZ201641)and Petro China.
文摘Five different internals were designed,and their effects on phase holdup and backmixing were investigated in a gas–liquid concurrent upflow reactor where the spherical alumina packing particles of three diameters(3.0,4.5 and6.0 mm)were slightly expanded under the conditions of varied superficial gas velocities(6.77×10^(-2)-3.61×10^(-1) m·s^(-1))and superficial liquid velocities(9.47×10^(-4)-2.17×10^(-3) m·s^(-1)).The experimental results show that the gas holdup increases with the superficial gas velocity and particle size,opposite to the variational trend of liquid holdup.When an internal component is installed amid the upflow reactor,a higher gas holdup,a less liquid holdup and a larger Peclet number characterizing the weaker backmixing are obtained compared to those in the bed without internals under the same operating conditions.Additionally,the minimal backmixing is observed in the reactor equipped with the internals with a novel multi-step design.Finally,empirical correlations were proposed for estimating gas holdup,liquid holdup and Peclet number with the relative deviations within 11%,12%and 25%,respectively.
基金supported by the National Natural Science Foundation of China(Nos.U20B2011 and 123B2086)。
文摘The vapor diffusion and transport resulting from steam generator tube rupture(SGTR)accidents are a major concern threatening lead-based reactor core safety.In this study,a high-parameter SGTR experimental platform and the multi-phase multi-physics processes numerical simulation were developed to investigate the phase behavior and interaction mechanisms.This study revealed the interaction mechanisms of lead-bismuth liquid metal and water driven by flash vaporization,jet impingement boiling,and moderate boiling.The migration and evolution of the discrete phases(vapor-water mixture)were inferred from the temperature transient laws and a numerical simulation.The results revealed that the evolution of the discrete phases consists of three stages:cavity formation,flanking diffusion,and stable up-floating.The jet pressure significantly extended the disturbance period.Variations in the water temperature mainly affected the depressurization boiling process,altering the diffusion region of the discrete phases.The temperature of the liquid metal and the duration of the jet had a minimal impact on the behavior of the discrete phases.This study provides a crucial reference for constructing a complete picture of accident evolution.
文摘A new chemiluminescence flow system has been developed for sequential determina-tion of benzoic acid based on the reaction of the compound with copper carbonate entrapped in a solid-phase reactor. It was found that the unsaturated complex of Cu(II) and benzoic acid (1:1) has strong catalytic effect on the luminol-H2O2 chemiluminescence reaction. The calibration graph is linear over the range of 0.025 ~ 60 g/mL of benzoic acid, with a relative standard deviation of less than 3.0 %, and the detection limit is 0.01礸穖L-1. The proposed method was applied to the determination of benzoic acid content in different pharmaceutical formulations.
文摘Hursts rescaled range (R/S) analysis and Wolfs attractor reconstruction technique have been adopted to estimate the local fractal dimensions and the local largest Lyapunov exponents in terms of the time series pressure fluctuations obtained from a gas liquid solid three phase self aspirated reversed flow jet loop reactor,respectively.The results indicate that the local fractal dimensions and the local largest Lyapunov exponents in both the jet region and the tubular region inside the draft tube increase with the increase in the jet liquid flowrates and the solid loadings,the local fractal dimension profiles are similar to those of the largest Lyapunov exponent,the local largest lyapunov exponents are positive for all cases,and the flow behavior of such a reactor is chaotic.The local nonlinear characteristic parameters such as the local fractal dimension and the local largest Lyapunov exponent could be applied to further study the flow properties such as the flow regime transitions and flow structures of this three phase jet loop reactor.
基金This work was supported by the National Basic Research Program of China (2005CB221205)
文摘A three-phase reactor mathematical model was set up to simulate and design a three-phase bubble column reactor for direct synthesis of dimethyl ether （DME） from syngas, considering both the influence of part inert carrier backmixing on transfer and the influence of catalyst grain sedimentation on reaction. On the basis of this model, the influences of the size and reaction conditions of a 100000 t/a DME reactor on capacity were investigated. The optimized size of the 10000 t/a DME synthesis reactor was proposed as follows： diameter 3.2 m, height 20 m, built-in 400 tube heat exchanger （Ф 38×2 mm）, and inert heat carrier paraffin oil 68 t and catalyst 34.46 t. Reaction temperature and pressure were important factors influencing the reaction conversion for different size reactors. Under the condition of uniform catalyst concentration distribution, higher pressure and temperature were proposed to achieve a higher production capacity of DME. The best ratio of fresh syngas for DME synthesis was 2.04.
基金supported by the National Natural Science Foundation of China (Nos. 51178215 and 51378251)the Jiangsu Nature Science Fund (No. BK2011032)+2 种基金Open Science Foundation of Jiangsu (No. 50808121)the National Science and Technology Major Project for Water Pollution Control and Treatment (No. 2012ZX07301-005)the 2012 Scientific Research Open Found of Jiangsu Key Laboratory of Environmental Engineering
文摘A two-phase anaerobic reactor fed with glucose substrate（3 g chemical oxygen demand（COD）/L） was used to investigate the effects of toxic metals on the degradation of organics and the soluble microbial product（SMP） formation. Low concentrations of Ni（II）（5 and10 mg/L） promoted the acid phase, whereas high concentrations（15, 20, and 25 mg/L）exhibited an inhibitory effect on, but did not alter the fermentative method, which mainly involved the fermentation of propionic acid. The methanogenic microorganism exhibited a strong capability adapting constantly increased Ni（II） levels. The acid phase was an accumulation stage of SMP. In the absence of Ni（II）, the high-molecular-weight material in the effluent SMP mainly contained polysaccharide, tryptophan, and casein. Methanogens metabolized most of the polysaccharide, the whole tryptophan content, and part of the casein, leading to the presence of humic acid and protein in effluent. After Ni（II） dosage, the protein and polysaccharide of the acid phase increased, and tryptophan changed, while casein remained stable. More protein than polysaccharide was produced, suggesting the prominent function of protein when addressing the negative effect of toxic metals. The analysis of DNA confirmed the change of bacterial activity.
基金Supported by the National Natural Science Foundation of China andExtraction Separation branch of United Chemical Engineeing
文摘The synthesis of dipeptide AcPheLeuNH2 catalyzed by immobilized pancreatic lipase was carried out in a two- liquid-phase hollow-fiber membrane reactor, operated in a batch mode. Kinetic properties of free and immobilized enzyme, partition behavior between aqueous buffer phase and organic solvent phase, and effective diffusion coefficients of substrates and products through the membrane were investigated respectively. Based on the preliminary experimental results, the performance of the enzyme membrane reactor, which is evaluated by the purity and the yield, is discussed.
文摘By means of cavity-assisted photon interference, a simple scheme is proposed to implement a symmetric economical phase-covariant quantum cloning machine of two remote qubits, with each in a separate cavity. With our present scheme, a high-fidelity cloning machine is realized. Our scheme may be quite useful in terms of distributed quantum information processing.
文摘Riser reactor is a key unit in the Fluid Catalytic Cracking (FCC), and it has important influences on increasing the yield coefficient of gas and oil. In this paper, the behaviors of gas-solid two-phase flow in the traditional y-type riser reactor are investigated by numerical simulation. The calculated particle concentration distribution is in good agreement with the experimental data, which verified the advanced models and calculating methods. The non-uniform distribution, such as core-annulus flow, may result in the unreasonable matching relationship of catalyst-to-oil ratio. An optimized riser with cuneal internals is proposed and the comparison of two different structures of riser reactor is presented. The comparison results show that the cuneal internals in the riser both can block effectively the slip down of the particles near wall region and weaken core-annulus flow structure due to the redistribution of particles. The results also prove that the particle concentration distribution becomes uniform along the axial and radial direction in the optimized riser by adding cuneal internals, which would be benefits for the catalytic cracking reactions.
文摘Some kinds of break in the reactor coolant system may cause the coolant to exit rapidly from the failure site,which leads to the loss of coolant accident(LOCA).In this paper,a stress analysis of an AP1000 reactor containment is performed in an LOCA,with the passive containment cooling system(PCCS) being available and not available for cooling the wall's containment.The variations in the mechanical properties of the wall's containment,including elastic modulus,strength,and stress,are analyzed using the ABAQUS code.A general two-phase model is applied for modeling thermal-hydraulic behavior inside the containment.Obtained pressure and temperature from thermal-hydraulic models are considered as boundary conditions of the ABAQUS code to obtain distributions of temperature and stress across steel shell of the containment in the accident.The results indicate that if the PCCS fails,the peak pressure inside the containment exceeds the design value.However,the stress would still be lower than the yield stress value,and no risk would threaten the integrity of the containment.
