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Facile synthesis of hierarchical NaX zeolite from natural kaolinite for efficient Knoevenagel condensation 被引量:2
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作者 Wen Xiao Peng Dong +6 位作者 Chan Wang Jingdong Xu Tiesen Li Haibo Zhu Tinghai Wang Renwei Xu Yuanyuan Yue 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第1期75-84,共10页
Zeolite catalysts have found extensive applications in the synthesis of various fine chemicals.However,the micropores of zeolites impose diffusion limitations on bulky molecules,greatly reducing the catalytic efficien... Zeolite catalysts have found extensive applications in the synthesis of various fine chemicals.However,the micropores of zeolites impose diffusion limitations on bulky molecules,greatly reducing the catalytic efficiency.Herein,we explore an economic and environmentally friendly method for synthesizing hierarchical NaX zeolite that exhibits improved catalytic performance in the Knoevenagel condensation reaction for producing the useful fine chemical 2-cyano-3-phenylacrylate.The synthesis was achieved via a low-temperature activation of kaolinite and subsequent in-situ transformation strategy without any template or seed.Systematic characterizations reveal that the synthesized NaX zeolite has both intercrystalline and intra-crystalline mesopores,smaller crystal size,and larger external specific surface area compared to commercial NaX zeolite.Detailed mechanism investigations show that the inter-crystalline mesopores are generated by stacking smaller crystals formed from in-situ crystallization of the depolymerized kaolinite,and the intra-crystalline mesopores are inherited from the pores in the depolymerized kaolinite.This synthesis strategy provides an energy-saving and effective way to construct hierarchical zeolites,which may gain wide applications in fine chemical manufacturing. 展开更多
关键词 Hierarchical NaX zeolite Template-free synthesis Natural kaolinite Knoevenagel condensation
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Chromatin condensation but not DNA integrity of pig sperm is greater in the sperm-rich fraction
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作者 Estel Viñolas-Vergés Jordi Ribas-Maynou +4 位作者 Isabel Barranco Camila Peres Rubio Sergi Bonet Jordi Roca Marc Yeste 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第1期171-181,共11页
Background Protamination and condensation of sperm chromatin as well as DNA integrity play an essential role during fertilization and embryo development.In some mammals,like pigs,ejaculates are emitted in three separa... Background Protamination and condensation of sperm chromatin as well as DNA integrity play an essential role during fertilization and embryo development.In some mammals,like pigs,ejaculates are emitted in three separate fractions:pre-sperm,sperm-rich(SRF)and post sperm-rich(PSRF).These fractions are known to vary in volume,sperm concentration and quality,as well as in the origin and composition of seminal plasma(SP),with differences being also observed within the SRF one.Yet,whether disparities in the DNA integrity and chromatin condensation and pro-tamination of their sperm exist has not been interrogated.Results This study determined chromatin protamination(Chromomycin A3 test,CMA_(3)),condensation(Dibromobi-mane test,DBB),and DNA integrity(Comet assay)in the pig sperm contained in the first 10 m L of the SRF(SRF-P1),the remaining portion of the sperm-rich fraction(SRF-P2),and the post sperm-rich fraction(PSRF).While chromatin protamination was found to be similar between the different ejaculate fractions(P>0.05),chromatin condensation was seen to be greater in SRF-P1 and SRF-P2 than in the PSRF(P=0.018 and P=0.004,respectively).Regarding DNA integrity,no differences between fractions were observed(P>0.05).As the SRF-P1 has the highest sperm concentra-tion and ejaculate fractions are known to differ in antioxidant composition,the oxidative stress index(OSi)in SP,calcu-lated as total oxidant activity divided by total antioxidant capacity,was tested and confirmed to be higher in the SRF-P1 than in SRF-P2 and PSRF(0.42±0.06 vs.0.23±0.09 and 0.08±0.00,respectively;P<0.01);this index,in addition,was observed to be correlated to the sperm concentration of each fraction(Rs=0.973;P<0.001).Conclusion While sperm DNA integrity was not found to differ between ejaculate fractions,SRF-P1 and SRF-P2 were observed to exhibit greater chromatin condensation than the PSRF.This could be related to the OSi of each fraction. 展开更多
关键词 CHROMATIN condensation DNA integrity Ejaculate fractions PIG Protamination SPERM
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Controllable Condensation of Aromatics and Its Mechanisms in Carbonization
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作者 Fan Xi Wang Chunlu +3 位作者 Luo Yang Ren Qiang Shen Haiping Long Jun 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2024年第1期34-46,共13页
In order to obtain liquefied products with higher yields of aromatic molecules to produce mesophase pitch,a good understanding of the relevant reaction mechanisms is required.Reactive molecular dynamics simulations we... In order to obtain liquefied products with higher yields of aromatic molecules to produce mesophase pitch,a good understanding of the relevant reaction mechanisms is required.Reactive molecular dynamics simulations were used to study the thermal reactions of pyrene,1-methylpyrene,7,8,9,10-tetrahydrobenzopyrene,and mixtures of pyrene with 1-octene,cyclohexene,or styrene.The reactant conversion rates,reaction rates,and product distributions were calculated and compared,and the mechanisms were analyzed and discussed.The results demonstrated that methyl and naphthenic structures in aromatics might improve the conversion rates of reactants in hydrogen transfer processes,but their steric hindrances prohibited the generation of high polymers.The naphthenic structures could generate more free radicals and presented a more obvious inhibition effect on the condensation of polymers compared with the methyl side chains.It was discovered that when different olefins were mixed with pyrene,1-octene primarily underwent pyrolysis reactions,whereas cyclohexene mainly underwent hydrogen transfer reactions with pyrene and styrene,mostly producing superconjugated biradicals through condensation reactions with pyrene.In the mixture systems,the olefins scattered aromatic molecules,hindering the formation of pyrene trimers and higher polymers.According to the reactive molecular dynamics simulations,styrene may enhance the yield of dimer and enable the controlled polycondensation of pyrene. 展开更多
关键词 CARBONIZATION controllable condensation AROMATICS MECHANISMS molecular simulation
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Supersonic expansion and condensation characteristics of hydrogen gas under different temperature conditions
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作者 Xinyue Duan Zeyu Zhang +4 位作者 Ziyuan Zhao Yang Liu Liang Gong Xuewen Cao Jiang Bian 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第5期220-226,共7页
This paper introduced supersonic expansion liquefaction technology into the field of hydrogen liquefaction.The mathematical model for supersonic condensation of hydrogen gas in a Laval nozzle model was established.The... This paper introduced supersonic expansion liquefaction technology into the field of hydrogen liquefaction.The mathematical model for supersonic condensation of hydrogen gas in a Laval nozzle model was established.The supersonic expansion and condensation characteristics of hydrogen gas under different temperature conditions were investigated.The simulation results show that the droplet number rises rapidly from 0 at the nozzle throat as the inlet temperature increases,and the maximum droplet number generated is 1.339×10^(18)kg^(-1)at inlet temperature of 36.0 K.When hydrogen nucleation occurs,the droplet radius increases significantly and shows a positive correlation with the increase in the inlet temperature,and the maximum droplet radii are 6.667×10^(-8)m,1.043×10^(-7)m,and 1.099×10^(-7)m when the inlet temperature is 36.0 K,36.5 K,and 37.0 K,respectively.The maximum nucleation rate decreases with increasing inlet temperature,and the nucleation region of the Laval nozzle becomes wider.The liquefaction efficiency can be effectively improved by lowering the inlet temperature.This is because a lower inlet temperature provides more subcooling,which allows the hydrogen to reach the thermodynamic conditions required for large-scale condensation more quickly. 展开更多
关键词 HYDROGEN LIQUEFACTION SUPERSONIC condensation Laval nozzle Computational fluid dynamics
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Low-condensation diesel use contributes to winter haze in cold regions of China
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作者 Weiwei Song Mengying Wang +7 位作者 Yixuan Zhao Yu Bo Wanying Yao Ruihan Chen Xianshi Wang Xiaoyan Wang Chunhui Li Kebin He 《Environmental Science and Ecotechnology》 SCIE 2024年第6期226-232,共7页
The application of low-condensation diesel in cold regions with extremely low ambient temperatures(−14 to−29°C)has enabled the operation of diesel vehicles.Still,it may contribute to heavy haze pollution in cold ... The application of low-condensation diesel in cold regions with extremely low ambient temperatures(−14 to−29°C)has enabled the operation of diesel vehicles.Still,it may contribute to heavy haze pollution in cold regions during winter.Here we examine pollutant emissions from low-condensation diesel in China.We measure the emissions of elemental carbon(EC),organic carbon(OC),and elements,including heavy metals such as arsenic(As).Our results show that low-condensation diesel increased EC and OC emissions by 2.5 and 2.6 times compared to normal diesel fuel,respectively.Indicators of vehicular sources,including EC,As,lead(Pb),cadmium(Cd),chromium(Cr),nickel(Ni),and manganese(Mn),increased by approximately 20.2-162.5%when using low-condensation diesel.Seasonal variation of vehicular source indicators,observed at road site ambient environments revealed the enhancement of PM2.5 pollution by the application of low-condensation diesel in winter.These findings suggest that−35#diesel,a low-cetane index diesel,may enhance air pollution in winter,according to a dynamometer test conducted in laboratory.It raises questions about whether higher emissions are released if−35#diesel is applied to running vehicles in real-world cold ambient environments. 展开更多
关键词 Low condensation diesel Carbonaceous matterHeavy metal DYNAMOMETER Cold regions
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Finite-Time Thermodynamic Simulation of Circulating Direct Condensation Heat Recovery on Chillers
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作者 Zhixin Yang Feihu Chen +1 位作者 Liping Wang Guangcai Gong 《Journal of Power and Energy Engineering》 2024年第1期1-14,共14页
A time series model is used in this paper to describe the progress of circulating direct condensation heat recovery of the compound condensing process (CCP) which is made of two water cooling condensing processes in s... A time series model is used in this paper to describe the progress of circulating direct condensation heat recovery of the compound condensing process (CCP) which is made of two water cooling condensing processes in series for a centrifugal chiller in the paper. A finite-time thermodynamics method is used to set up the time series simulation model. As a result, an upper bound of recoverable condensation heat for the compound condensing process is obtained which is in good agreement with experimental result. And the result is valuable and useful to optimization design of condensing heat recovery. 展开更多
关键词 condensation Heat Recovery Compound condensing Process Time Series Finite-Time Thermodynamics
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Generalized polynomial chaos expansion by reanalysis using static condensation based on substructuring
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作者 D.LEE S.CHANG J.LEE 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第5期819-836,共18页
This paper presents a new computational method for forward uncertainty quantification(UQ)analyses on large-scale structural systems in the presence of arbitrary and dependent random inputs.The method consists of a gen... This paper presents a new computational method for forward uncertainty quantification(UQ)analyses on large-scale structural systems in the presence of arbitrary and dependent random inputs.The method consists of a generalized polynomial chaos expansion(GPCE)for statistical moment and reliability analyses associated with the stochastic output and a static reanalysis method to generate the input-output data set.In the reanalysis,we employ substructuring for a structure to isolate its local regions that vary due to random inputs.This allows for avoiding repeated computations of invariant substructures while generating the input-output data set.Combining substructuring with static condensation further improves the computational efficiency of the reanalysis without losing accuracy.Consequently,the GPCE with the static reanalysis method can achieve significant computational saving,thus mitigating the curse of dimensionality to some degree for UQ under high-dimensional inputs.The numerical results obtained from a simple structure indicate that the proposed method for UQ produces accurate solutions more efficiently than the GPCE using full finite element analyses(FEAs).We also demonstrate the efficiency and scalability of the proposed method by executing UQ for a large-scale wing-box structure under ten-dimensional(all-dependent)random inputs. 展开更多
关键词 forward uncertainty quantification(UQ) generalized polynomial chaos expansion(GPCE) static reanalysis method static condensation SUBSTRUCTURING
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Reducing Condensation Inside the Photovoltaic(PV)Inverter according to the Effect of Diffusion as a Process of Vapor Transport
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作者 Amal El Berry Marwa M.Ibrahim +1 位作者 A.A.Elfeky Mohamed F.Nasr 《Frontiers in Heat and Mass Transfer》 EI 2024年第4期1189-1207,共19页
A photovoltaic(PV)inverter is a vital component of a photovoltaic(PV)solar system.Photovoltaic(PV)inverter failure can mean a solar system that is no longer functioning.When electronic devices such as photovoltaic(PV)... A photovoltaic(PV)inverter is a vital component of a photovoltaic(PV)solar system.Photovoltaic(PV)inverter failure can mean a solar system that is no longer functioning.When electronic devices such as photovoltaic(PV)inverter devices are subjected to vapor condensation,a risk could occur.Given the amount of moisture in the air,saturation occurswhen the temperature drops to the dewpoint,and condensationmay formon surfaces.Numerical simulation with“COMSOL Software”is important for obtaining knowledge relevant to preventing condensation by using two steps.At first,the assumption was that the device’s water vapor concentration was homogeneous to evaluate the amount of liquid water accumulated on the internal walls of the photovoltaic(PV)inverter box.Second,by considering the effect of external wind velocity onmoisture transport at the air interface to evaluate water vapor transport outdoors and reduce condensation.General factorial designs are utilized for analyzing the nature of the relationship between the vapor condensation response and the variables.Reducing vapor condensation inside the solar inverter by the effect of external wind speed on diffusion as a process of transporting moister air outside the inverter box is the main solution for this problem.During the movement and assessment of the flow of water vapor,the impact of vapor condensation is reduced.The saturation period was determined by using a Boolean saturation indicator.The saturation indicator was set to 1 when saturation was detected(relative humidity greater than or equal to 1)and 0 otherwise.Calculating the flow and dispersion of moist air as a function of wind speed helped solve the problem. 展开更多
关键词 PHOTOVOLTAIC INVERTER failure vapor condensation wind velocity diffusion transport and general factorial
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New Strategy Leverages Lignin Condensation for Biomass Utilization
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作者 WANG Feng 《Bulletin of the Chinese Academy of Sciences》 2024年第2期107-108,共2页
There is an old saying in the biorefining industry that“You can make anything from lignin except money.”This bio-based compound is abundant and full of potential,but commercializing it remains a challenge.This may n... There is an old saying in the biorefining industry that“You can make anything from lignin except money.”This bio-based compound is abundant and full of potential,but commercializing it remains a challenge.This may no longer be the case soon with an innovative approach by chemists from the Dalian Institute of Chemical Physics(DICP)of the Chinese Academy of Sciences and their colleagues to harness lignin condensation–often considered a nuisance–for efficient utilization of lignocellulose. 展开更多
关键词 condensation condensation BIOMASS
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利用改进的Pictet-Spengler反应合成多取代β-咔啉
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作者 钟铮 张京玉 +1 位作者 密霞 杨怀霞 《合成化学》 CAS 2023年第10期793-797,共5页
β-咔啉结构广泛存在于生物活性分子之中,为探索非酸性反应条件下合成β-咔啉衍生物的方法,以色胺类化合物和醛类为原料,以改进的Pictet-Spengler反应为关键步骤,再经氧化脱氢合成4个多取代β-咔啉化合物(2a~2d),其结构经1 H NMR和MS(E... β-咔啉结构广泛存在于生物活性分子之中,为探索非酸性反应条件下合成β-咔啉衍生物的方法,以色胺类化合物和醛类为原料,以改进的Pictet-Spengler反应为关键步骤,再经氧化脱氢合成4个多取代β-咔啉化合物(2a~2d),其结构经1 H NMR和MS(ESI)确证。经过对Pictet-Spengler反应步骤中物料比、溶剂、反应温度与时间进行考察后发现:在色胺类化合物为2.0 mmol,醛为3.0 mmol,六氟异丙醇钙为0.4 mmol,二氯甲烷为20.0 mL,室温反应24 h的最优条件下,四氢-β-咔啉化合物中间体(1a~1d)的收率为75%~89%,反应存在取代基效应,含芳香性基团底物收率较高。 展开更多
关键词 β-咔啉 pictet-spengler反应 色胺 六氟异丙醇钙 四氢-β-咔啉 氧化脱氢反应 2 3-二氯-5 6-二氰对苯醌(DDQ)
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Preparation of waterborne polyurethane/β-cyclodextrin composite nanosponge by ion condensation method and its application in removing of dyes from wastewater 被引量:1
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作者 Shanghong Ma Haitao Zhang +6 位作者 Jianbo Qu Xiuzhong Zhu Qingfei Hu Jianyong Wang Peng Ye Futao Sai Shiwei Chen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第6期124-136,共13页
Currently,polymer nanosponges have received extensive attention.However,developing new synthetic techniques for novel nanosponges remains a challenge.Furthermore,to date,composite nanosponge adsorbents based on waterb... Currently,polymer nanosponges have received extensive attention.However,developing new synthetic techniques for novel nanosponges remains a challenge.Furthermore,to date,composite nanosponge adsorbents based on waterborne polyurethane(WPU)andβ-cyclodextrin(β-CD)have not been reported.Herein,a novel green method,ion condensation method,was developed in this study for the preparation of polymer nanosponge adsorbents for efficient removal of dyes from wastewater.Based on the principle of charge repulsion between nanoparticles to maintain emulsion stability,waterborne polyurethane/β-cyclodextrin composite nanosponges(WPU-x,y)were prepared by coagulating the emulsions synthesized from 2,2-dimethylolpropionic acid,polypropylene glycol and hexamethylene diisocyanate as raw materials in a mixture of hydrochloric acid and anhydrous ethanol.The structure and appearance of WPU-x,y were characterized by attenuated total reflectance Fourier transform infrared spectroscopy,thermal gravimetric analyzer,scanning electron microscope and mercury intrusion porosimetry.The adsorption capacity of WPU-x,y was tested by parameters such as cross-linking degree,β-CD dosage,contact time,initial dye concentration and p H value.The study found that WPU-4,4.62 had the best adsorption effect on methylene blue(MB),the maximum removal rate was 93.42%,and the maximum adsorption capacity was 136.03 mg·g^(-1).Moreover,the Sips isotherm and pseudo-second-order-model were suitable for MB adsorption.Therefore,this study provides some perspectives for the fabrication of nanosponge adsorbents. 展开更多
关键词 Ion condensation Composites Nanomaterials Waterborne polyurethane(WPU) β-Cyclodextrin(β-CD) Adsorption
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Novel interface engineering of LDH-based materials on Mg alloy for efficient photocatalytic systems considering the geometrical linearity of condensed phosphates 被引量:3
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作者 Mosab Kaseem Ananda Repycha Safira Arash Fattah-alhosseini 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第1期267-280,共14页
This study presents a facile and rapid method for synthesizing novel Layered Double Hydroxide(LDH)nanoflakes,exploring their application as a photocatalyst,and investigating the influence of condensed phosphates'g... This study presents a facile and rapid method for synthesizing novel Layered Double Hydroxide(LDH)nanoflakes,exploring their application as a photocatalyst,and investigating the influence of condensed phosphates'geometric linearity on their photocatalytic properties.Herein,the Mg O film,obtained by plasma electrolysis of AZ31 Mg alloys,was modified by growing an LDH film,which was further functionalized using cyclic sodium hexametaphosphate(CP)and linear sodium tripolyphosphate(LP).CP acted as an enhancer for flake spacing within the LDH structure,while LP changed flake dispersion and orientation.Consequently,CP@LDH demonstrated exceptional efficiency in heterogeneous photocatalysis,effectively degrading organic dyes like Methylene blue(MB),Congo red(CR),and Methyl orange(MO).The unique cyclic structure of CP likely enhances surface reactions and improves the catalyst's interaction with dye molecules.Furthermore,the condensed phosphate structure contributes to a higher surface area and reactivity in CP@LDH,leading to its superior photocatalytic performance compared to LP@LDH.Specifically,LP@LDH demonstrated notable degradation efficiencies of 93.02%,92.89%,and 88.81%for MB,MO,and CR respectively,over a 40 min duration.The highest degradation efficiencies were observed in the case of the CP@LDH sample,reporting 99.99%for MB,98.88%for CR,and 99.70%for MO.This underscores the potential of CP@LDH as a highly effective photocatalyst for organic dye degradation,offering promising prospects for environmental remediation and water detoxification applications. 展开更多
关键词 Plasma electrolysis Layered Double Hydroxide condensed phosphates Adsorption capacity Photocatalytic efficiency
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In Tube Condensation:Changing the Pressure Drop into a Temperature Difference for a Wire-on-Tube Heat Exchanger
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作者 Louay Abd Al-Azez Mahdi Mohammed A.Fayad Miqdam T.Chaichan 《Fluid Dynamics & Materials Processing》 EI 2023年第9期2201-2214,共14页
A theoretical study based on the Penalty factor(PF)method by Cavallini et al.is conducted to show that the pressure drop occurring in a wire-on-tube heat exchanger can be converted into a temperature difference for tw... A theoretical study based on the Penalty factor(PF)method by Cavallini et al.is conducted to show that the pressure drop occurring in a wire-on-tube heat exchanger can be converted into a temperature difference for two types of refrigerants R-134a and R-600a typically used for charging refrigerators and freezers.The following conditions are considered:stratified or stratified-wavyflow condensation occurring inside the smooth tube of a wire-on-tube condenser with diameter 3.25,4.83,and 6.299 mm,condensation temperatures 35℃,45℃,and 54.4℃ and cover refrigerant massflow rate spanning the interval from 1 to 7 kg/hr.The results show that the PF variation is not linear with vapor quality and attains a maximum when the vapor quality is 0.2 and 0.18 for the R-134a and R-600a refrigerants,respectively.The PF increases with the refrigerant massflow rate if the inner diameter and saturation temperature constant,and it decreases on increasing the inner diameter to 6.299 mm for constant refrigerant massflow rate and saturation temperature.The PF for R-600a is higher than that for R-134a due to the lower saturation pressure in thefirst case.Furthermore,a stratifiedflow produces higher PF in comparison to the annularflow due to the effect of the surface tension. 展开更多
关键词 condensation penalty factor pressure drop temperature difference TWO-PHASE wire condenser
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不对称Pictet-Spengler反应中有机催化研究进展
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作者 孙玉虹 赵玮佳 +2 位作者 穆宏文 王黎明 金瑛 《分子催化》 CAS CSCD 北大核心 2023年第4期375-388,I0003,共15页
手性四氢-β-咔啉骨架广泛存在于天然产物和药物分子中,是其活性的关键结构.不对称Pictet-Spengler反应是高效构建四氢-β-咔啉化合物的直接途径.根据有机催化剂种类,我们从手性磷酸、手性方酰胺和其他催化剂3个方面,综述了近5年来有机... 手性四氢-β-咔啉骨架广泛存在于天然产物和药物分子中,是其活性的关键结构.不对称Pictet-Spengler反应是高效构建四氢-β-咔啉化合物的直接途径.根据有机催化剂种类,我们从手性磷酸、手性方酰胺和其他催化剂3个方面,综述了近5年来有机催化不对称Pictet-Spengler反应的研究进展. 展开更多
关键词 四氢-β-咔啉 pictet-spengler反应 不对称催化
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Numerical study of the deep removal of R134a from non-condensable gas mixture by cryogenic condensation and de-sublimation
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作者 Hongbo Tan Boshi Shao Na Wen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第9期180-191,共12页
Nowadays,the limits on greenhouse gas emissions are becoming increasingly stringent.In present research,a two-dimensional numerical model was established to simulate the deep removal of 1,1,1,2-tetrafluoroethane(R134a... Nowadays,the limits on greenhouse gas emissions are becoming increasingly stringent.In present research,a two-dimensional numerical model was established to simulate the deep removal of 1,1,1,2-tetrafluoroethane(R134a)from the non-condensable gas(NCG)mixture by cryogenic condensation and de-sublimation.The wall condensation method was compiled into the Fluent software to calculate the condensation of R134a from the gas mixture.Besides,the saturated thermodynamic properties of R134a under its triple point were extrapolated by the equation of state.The simulation of the steam condensation with NCG was conducted to verify the validity of the model,the results matched well with the experimental data.Subsequently,the condensation characteristics of R134a with NCG and the thermodynamic parameters affecting condensation were studied.The results show that the section with relatively higher removal efficiency is usually near the inlet.The cold wall temperature has a great influence on the R134a removal performance,e.g.,a 15 K reduction of the wall temperature brings a reduction in the outlet R134a molar fraction by 85.43%.The effect of changing mass flow rate on R134a removal is mainly reflected at the outlet,where an increase in mass flow rate of 12.6% can aggravate the outlet molar fraction to 210.3% of the original.The research can provide a valuable reference for the simulation of the deep removal of various low-concentration gas using condensation and de-sublimation methods. 展开更多
关键词 Numerical simulation Greenhouse gas condensation De-sublimation Vapor deep removal Non-condensable gas
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Theoretical and Experimental Analysis of Heat Transfer and Condensation in Micro-Ribbed Tubes
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作者 Daoming Shen Jinhong Xia +1 位作者 Chao Gui Songtao Xue 《Fluid Dynamics & Materials Processing》 EI 2023年第6期1411-1424,共14页
The thermal transmission coefficient for a micro-ribbed tube has been determined using theoretical relationships and the outcomes of such calculations have been compared with experiments conducted using a R1234yf refr... The thermal transmission coefficient for a micro-ribbed tube has been determined using theoretical relationships and the outcomes of such calculations have been compared with experiments conducted using a R1234yf refrigerant undergoing condensation.In particular four theoretical single-phase flow and three multi-phase flow models have been used in this regard.The experimental results show that:the Oliver et al.criterion equation overestimates the experimental results as its accuracy is significantly affected by the specific conditions realized inside micro-fin tubes;the Miyara et al.criterion equation prediction error is less than 15%;the Cavallini et al.approach gives the highest prediction accuracy;the Goto et al.model overestimates the test data.Such results are critically discussed and some indications for the improvement of such models are provided. 展开更多
关键词 Micro-ribbed tube flow condensation thermal transmission coefficient dimensionless criterion equation
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Title Supersonic Condensation and Separation Characteristics of CO_(2)-Rich Natural Gas under Different Pressures
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作者 Yong Zheng Lei Zhao +6 位作者 YujiangWang Feng Chang Weijia Dong Xinying Liu Yunfei Li Xiaohan Zhang Ziyuan Zhao 《Energy Engineering》 EI 2023年第2期529-540,共12页
Supersonic separation technology is a new natural gas sweetening method for the treatment of natural gas with high CO_(2)(carbon dioxide)content.The structures of the Laval nozzle and the supersonic separator were des... Supersonic separation technology is a new natural gas sweetening method for the treatment of natural gas with high CO_(2)(carbon dioxide)content.The structures of the Laval nozzle and the supersonic separator were designed,and the mathematical models of supersonic condensation and swirling separation for CO_(2)-CH4 mixture gas were established.The supersonic condensation characteristics of CO_(2) in natural gas and the separation characteristics of condensed droplets under different inlet pressures were studied.The results show that higher inlet pressure results in a larger droplet radius and higher liquid phase mass fraction;additionally,the influence of centrifugal force is more pronounced,and the separation efficiency and removal efficiency of CO_(2) are higher.When the inlet pressure is 6 and 9 MPa,the liquefaction efficiency at the Laval nozzle outlet increases from 56.90%to 79.97%,and the outlet droplet radius increases from 0.39 to 0.72μm,and the removal efficiency is 31.25%and 54.52%,respectively.The effects of inlet pressures on the removal efficiency of the supersonic separator are complicated and are controlled by the combined effects of liquefaction capacity of the nozzle and centrifugal separation capacity of the swirl vane. 展开更多
关键词 Supersonic separator Laval nozzle natural gas carbon dioxide condensation separation
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Effects of Ethanol Condensation Reflux Extraction and Ultrasound-assisted Extraction on the Content of Total Flavonoids of Pueraria edulis
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作者 Jun TANG Jianguang ZENG +1 位作者 Hao LI Chenzhong JIN 《Agricultural Biotechnology》 CAS 2023年第2期91-95,104,共6页
With Pueraria edulis from different habitats in Yunnan Province,Guangdong Province and Guangxi Zhuang autonomous region as materials,the medicinal materials of P.edulis were extracted by ethanol condensation reflux ex... With Pueraria edulis from different habitats in Yunnan Province,Guangdong Province and Guangxi Zhuang autonomous region as materials,the medicinal materials of P.edulis were extracted by ethanol condensation reflux extraction and ultrasound-assisted extraction,and the effects of different extraction methods the contents of total flavonoids in P.edulis from different areas were compared.The results showed that the best extraction time for P.edulis in Yunnan Province was 20 min,and that for Guangdong and Guangxi Zhuang Autonomous Region was 30 min.The yield of total flavonoids from P.edulis extracted by the condensation reflux extraction method was relatively better.The content of total flavonoids in P.edulis in Yunnan was the highest with an average content of 0.2557%,while the average content of total flavonoids in P.edulis in Guangdong was the lowest with an average content of 0.2108%. 展开更多
关键词 Pueraria edulis Total flavonoids condensation reflux extraction method Ultrasound-assisted extraction
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Phase behavior of gas condensate in porous media using real-time computed tomography scanning
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作者 Wen-Long Jing Lei Zhang +5 位作者 Ai-Fen Li Jun-Jie Zhong Hai Sun Yong-Fei Yang Yu-Long Cheng Jun Yao 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1032-1043,共12页
The phase behavior of gas condensate in reservoir formations differs from that in pressure-volume-temperature(PVT)cells because it is influenced by porous media in the reservoir formations.Sandstone was used as a samp... The phase behavior of gas condensate in reservoir formations differs from that in pressure-volume-temperature(PVT)cells because it is influenced by porous media in the reservoir formations.Sandstone was used as a sample to investigate the influence of porous media on the phase behavior of the gas condensate.The pore structure was first analyzed using computed tomography(CT)scanning,digital core technology,and a pore network model.The sandstone core sample was then saturated with gas condensate for the pressure depletion experiment.After each pressure-depletion state was stable,realtime CT scanning was performed on the sample.The scanning results of the sample were reconstructed into three-dimensional grayscale images,and the gas condensate and condensate liquid were segmented based on gray value discrepancy to dynamically characterize the phase behavior of the gas condensate in porous media.Pore network models of the condensate liquid ganglia under different pressures were built to calculate the characteristic parameters,including the average radius,coordination number,and tortuosity,and to analyze the changing mechanism caused by the phase behavior change of the gas condensate.Four types of condensate liquid(clustered,branched,membranous,and droplet ganglia)were then classified by shape factor and Euler number to investigate their morphological changes dynamically and elaborately.The results show that the dew point pressure of the gas condensate in porous media is 12.7 MPa,which is 0.7 MPa higher than 12.0 MPa in PVT cells.The average radius,volume,and coordination number of the condensate liquid ganglia increased when the system pressure was between the dew point pressure(12.7 MPa)and the pressure for the maximum liquid dropout,Pmax(10.0 MPa),and decreased when it was below Pmax.The volume proportion of clustered ganglia was the highest,followed by branched,membranous,and droplet ganglia.This study provides crucial experimental evidence for the phase behavior changing process of gas condensate in porous media during the depletion production of gas condensate reservoirs. 展开更多
关键词 Gas condensate Pressure depletion Real-time micro-computed tomography scanning Distribution of condensate liquid
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Experimental Investigation on Condensate Revaporization During Gas Injection Development in Fractured Gas Condensate Reservoirs
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作者 Lei Zhang Yingxu He +3 位作者 Jintao Wu Haojun Wu Lei Huang Linna Sun 《哈尔滨工程大学学报(英文版)》 CSCD 2024年第3期575-582,共8页
The gas field in the Bohai Bay Basin is a fractured metamorphic buried-hill reservoir with dual-media characteristics. The retrograde vaporization mechanism observed in this type of gas condensate reservoir differs si... The gas field in the Bohai Bay Basin is a fractured metamorphic buried-hill reservoir with dual-media characteristics. The retrograde vaporization mechanism observed in this type of gas condensate reservoir differs significantly from that observed in sand gas condensate reservoirs. However, studies on improving the recovery of fractured gas condensate reservoirs are limited;thus, the impact of retrograde vaporization on condensate within fractured metamorphic buried-hill reservoirs remains unclear. To address this gap, a series of gas injection experiments are conducted in pressure-volume-temperature(PVT) cells and long-cores to investigate the retrograde vaporization effect of condensate using different gas injection media in fractured gas condensate reservoirs. We analyze the variation in condensate volume, gas-to-oil ratio, and condensate recovery during gas injection and examine the influence of various gas injection media(CO_(2), N_(2), and dry gas) under different reservoir properties and varying gas injection times. The results demonstrate that the exchange of components between injected gas and condensate significantly influences condensate retrograde vaporization in the formation. Compared with dry gas injection and N_(2) injection,CO_(2) injection exhibits a superior retrograde vaporization effect. At a CO_(2) injection volume of 1 PV, the percentage shrinkage volume of condensate is 13.82%. Additionally, at the maximum retrograde condensation pressure, CO_(2) injection can increase the recovery of condensate by 22.4%. However, the condensate recovery is notably lower in fractured gas condensate reservoirs than in homogeneous reservoirs, owing to the creation of dominant gas channeling by fractures, which leads to decreased condensate recovery. Regarding gas injection timing, the effect of gas injection at reservoir pressure on improving condensate recovery is superior to that of gas injection at the maximum retrograde condensation pressure. This research provides valuable guidance for designing gas injection development plans and dynamic tracking adjustments for fractured gas condensate reservoirs. 展开更多
关键词 Buried-hill fractured reservoir Gas condensate reservoir Retrograde condensation CO_(2)injection Retrograde vaporization
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