Allelochemicals of Chinese-fir root was extracted by technology ofsupercritical CO_2 extraction under orthogonal experiment design, and it was used to analyzeallelopathic activity of Chinese-fir through bioassay of se...Allelochemicals of Chinese-fir root was extracted by technology ofsupercritical CO_2 extraction under orthogonal experiment design, and it was used to analyzeallelopathic activity of Chinese-fir through bioassay of seed germination. The results showed thatas to the available rate of allelochemicals, the pressure and temperature of extraction were themost important factors. The allelochemicals of Chinese-fir root extracted by pure CO_2 and ethanolmixed with CO_2 have different allelopathic activities to seed germination, and the allelochemicalsextracted by ethanol mixed with CO_2 had stronger inhibitory effects on seed germination than thatextracted by pure CO_2.展开更多
[Objective] This study aimed to investigate the differences in chemical composition of supercritical CO2 extraction products in peels of Trichosanthes kirilowii Maxim. from Changqing district. [Method] Supercritical f...[Objective] This study aimed to investigate the differences in chemical composition of supercritical CO2 extraction products in peels of Trichosanthes kirilowii Maxim. from Changqing district. [Method] Supercritical fluidextraction （SFE） and GCMS method were applied to determine and analyze the chemical components of the extracts in peels of three strains of Trichosanthes kirilowii Maxim. [Result] The chemical components of supercritical CO2 extraction products in peels of three strains of Trichosanthes kirilowii Maxim. varied., and the number of chemical components with normalized percentage content higher than 1% was 5, 7 and 8, respectively. There are 14 kinds of common components, and the relative content of hexadecanoic acid was the highest. [Conclusion] Supercritical CO2 extracts in peels of different strains of Trichosanthes kirilowii Maxim. contain different chemical components, providing scientific basis for breeding excellent varieties and the development and utilization of Trichosanthes kirilowii Maxim.展开更多
The supercritical CO_(2)(sCO_(2))power cycle could improve efficiencies for a wide range of thermal power plants.The sCO_(2)turbine generator plays an important role in the sCO_(2)power cycle by directly converting th...The supercritical CO_(2)(sCO_(2))power cycle could improve efficiencies for a wide range of thermal power plants.The sCO_(2)turbine generator plays an important role in the sCO_(2)power cycle by directly converting thermal energy into mechanical work and electric power.The operation of the generator encounters challenges,including high temperature,high pressure,high rotational speed,and other engineering problems,such as leakage.Experimental studies of sCO_(2)turbines are insufficient because of the significant difficulties in turbine manufacturing and system construction.Unlike most experimental investigations that primarily focus on 100 kW‐or MW‐scale power generation systems,we consider,for the first time,a small‐scale power generator using sCO_(2).A partial admission axial turbine was designed and manufactured with a rated rotational speed of 40,000 rpm,and a CO_(2)transcritical power cycle test loop was constructed to validate the performance of our manufactured generator.A resistant gas was proposed in the constructed turbine expander to solve the leakage issue.Both dynamic and steady performances were investigated.The results indicated that a peak electric power of 11.55 kW was achieved at 29,369 rpm.The maximum total efficiency of the turbo‐generator was 58.98%,which was affected by both the turbine rotational speed and pressure ratio,according to the proposed performance map.展开更多
The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle efficiency.Mathematical models of four Brayto...The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle efficiency.Mathematical models of four Brayton cycle layouts are developed in this study for different reactors to reduce the cost and increase the thermohydraulic performance of nuclear power generation to promote the commercialization of nuclear energy.Parametric analysis,multi-objective optimizations,and four decision-making methods are applied to obtain each Brayton scheme’s optimal thermohydraulic and economic indexes.Results show that for the same design thermal power scale of reactors,the higher the core’s exit temperature,the better the Brayton cycle’s thermo-economic performance.Among the four-cycle layouts,the recompression cycle(RC)has the best overall performance,followed by the simple recuperation cycle(SR)and the intercooling cycle(IC),and the worst is the reheating cycle(RH).However,RH has the lowest total cost of investment(C_(tot))of$1619.85 million,and IC has the lowest levelized cost of energy(LCOE)of 0.012$/(kWh).The nuclear Brayton cycle system’s overall performance has been improved due to optimization.The performance of the molten salt reactor combined with the intercooling cycle(MSR-IC)scheme has the greatest improvement,with the net output power(W_(net)),thermal efficiencyη_(t),and exergy efficiency(η_(e))improved by 8.58%,8.58%,and 11.21%,respectively.The performance of the lead-cooled fast reactor combined with the simple recuperation cycle scheme was optimized to increase C_(tot) by 27.78%.In comparison,the internal rate of return(IRR)increased by only 7.8%,which is not friendly to investors with limited funds.For the nuclear Brayton cycle,the molten salt reactor combined with the recompression cycle scheme should receive priority,and the gas-cooled fast reactor combined with the reheating cycle scheme should be considered carefully.展开更多
Proppant transport within fractures is one of the most critical tasks in oil,gas and geothermal reservoir stimulation,as it largely determines the ultimate performance of the operating well.Proppant transport in rough...Proppant transport within fractures is one of the most critical tasks in oil,gas and geothermal reservoir stimulation,as it largely determines the ultimate performance of the operating well.Proppant transport in rough fracture networks is still a relatively new area of research and the associated transport mechanisms are still unclear.In this study,representative parameters of rough fracture surfaces formed by supercritical CO_(2) fracturing were used to generate a rough fracture network model based on a spectral synthesis method.Computational fluid dynamics(CFD)coupled with the discrete element method(DEM)was used to study proppant transport in this rough fracture network.To reveal the turning transport mechanism of proppants into branching fractures at the intersections of rough fracture networks,a comparison was made with the behavior within smooth fracture networks,and the effect of key pumping parameters on the proppant placement in a secondary fracture was analyzed.The results show that the transport behavior of proppant in rough fracture networks is very different from that of the one in the smooth fracture networks.The turning transport mechanisms of proppant into secondary fractures in rough fracture networks are gravity-driven sliding,high velocity fluid suspension,and fracture structure induction.Under the same injection conditions,supercritical CO_(2)with high flow Reynolds number still has a weaker ability to transport proppant into secondary fractures than water.Thickening of the supercritical CO_(2)needs to be increased beyond a certain value to have a significant effect on proppant carrying,and under the temperature and pressure conditions of this paper,it needs to be increased more than 20 times(about 0.94 m Pa s).Increasing the injection velocity and decreasing the proppant concentration facilitates the entry of proppant into the branching fractures,which in turn results in a larger stimulated reservoir volume.The results help to understand the proppant transport and placement process in rough fracture networks formed by reservoir stimulation,and provide a theoretical reference for the optimization of proppant pumping parameters in hydraulic fracturing.展开更多
An experimental setup for separating ginger essential oil by supercritical fluid extraction is established. The effects of the extraction pressure, temperature, CO2 flow rate and particle size of raw material on the e...An experimental setup for separating ginger essential oil by supercritical fluid extraction is established. The effects of the extraction pressure, temperature, CO2 flow rate and particle size of raw material on the extraction rate are investigated, and the optimum process conditions of supercritical CO2 extraction are determined. A mathematical simulation model is established based on the mass conservation in differential units of extraction bed. The total mass transfer driving force and the equilibrium absorption constant are evaluated by the linear driving force theory. The results from numerical simulation agree well with the experimental data.展开更多
Extraction of heavy metal ions from solid matrix by means of an incorporation of chelating agents with supercritical carbon dioxide（scCO2） was investigated experimentally. Four commercially available chelating agent...Extraction of heavy metal ions from solid matrix by means of an incorporation of chelating agents with supercritical carbon dioxide（scCO2） was investigated experimentally. Four commercially available chelating agents, diethylammonium diethyldithiocarbamate（Et2NH2DDC）, trifluoroacetylacetone（TFA）, hexafluoroacetylacetone（HFA） and thenoyltrifluoroacetone（TTA） were tested. The extraction experiments were conducted at 50 °C and 1.39×107― 2.80×107 Pa. According to the experimental results, for the extraction of Cu2＋, all the chelating agents investigated here are effective. For other metal ions, such as Pb2＋, Ni2＋ and Cd2＋, Et2NH2DDC exhibited a better extraction result, while other chelating agents were less effective. This investigation is expected to provide a tentative evaluation on the scCO2-based metal extraction from solid media.展开更多
[Objectives]This study was conducted to establish a mathematical model for supercritical CO_(2) extraction of curcumin.[Methods]With ginger as the experimental raw material,a quadratic polynomial mathematical model of...[Objectives]This study was conducted to establish a mathematical model for supercritical CO_(2) extraction of curcumin.[Methods]With ginger as the experimental raw material,a quadratic polynomial mathematical model of the yield of curcumin extracted by supercritical CO_(2) was established by response surface methodology(RSM).The validity of the mathematical model was verified,and the effects of extraction temperature(60-70℃),pressure(30-50 MPa)and time(70-90 min)on curcumin yield were analyzed.[Results]According to the model,the process parameters were optimized.Taking curcumin yield as the index,the optimal process conditions for supercritical CO_(2) extraction obtained were:temperature 62.6℃,pressure 37.7 MPa,time 82.9 min,under which the yield of curcumin was as high as 7.34%.Under the optimal extraction conditions,curcumin had a certain reducing capacity,and showed strong scavenging capacities to·OH,O_(2)^(-)·and DPPH,and its IC_(50) values were 9.40,9.03 and 8.04 mg/ml,respectively.Therefore,it is feasible to extract curcumin from ginger using supercritical CO_(2).[Conclusions]This study provides a theoretical basis for the development and utilization of curcumin.展开更多
基金This paper was supported by Natural Science Foundation of Fujian Province (B0010020)
文摘Allelochemicals of Chinese-fir root was extracted by technology ofsupercritical CO_2 extraction under orthogonal experiment design, and it was used to analyzeallelopathic activity of Chinese-fir through bioassay of seed germination. The results showed thatas to the available rate of allelochemicals, the pressure and temperature of extraction were themost important factors. The allelochemicals of Chinese-fir root extracted by pure CO_2 and ethanolmixed with CO_2 have different allelopathic activities to seed germination, and the allelochemicalsextracted by ethanol mixed with CO_2 had stronger inhibitory effects on seed germination than thatextracted by pure CO_2.
基金Supported by Science and Technology Development Project of Shangdong Province "Study on Standardized Planting of Chinese Herbal Medicines in Central China and Comprehensive Development and Utilization Technology of Bulk Chinese Herbs"(2011BAI06B00)Construction Project of Scientific and Technological Plat form for Quality Control of Genuine Medicinal Materials in Shangdong Province(2008GG-2NS02022)+1 种基金Agricultural Thoroughbred Breeding Project of Shangdong Province(2009LZ01-03)Independent Innovation Project of Universities and Institutes from Science and Technology Bureau of Ji'nan City(200906028)~~
文摘[Objective] This study aimed to investigate the differences in chemical composition of supercritical CO2 extraction products in peels of Trichosanthes kirilowii Maxim. from Changqing district. [Method] Supercritical fluidextraction （SFE） and GCMS method were applied to determine and analyze the chemical components of the extracts in peels of three strains of Trichosanthes kirilowii Maxim. [Result] The chemical components of supercritical CO2 extraction products in peels of three strains of Trichosanthes kirilowii Maxim. varied., and the number of chemical components with normalized percentage content higher than 1% was 5, 7 and 8, respectively. There are 14 kinds of common components, and the relative content of hexadecanoic acid was the highest. [Conclusion] Supercritical CO2 extracts in peels of different strains of Trichosanthes kirilowii Maxim. contain different chemical components, providing scientific basis for breeding excellent varieties and the development and utilization of Trichosanthes kirilowii Maxim.
基金National Science Fund for Excellent Young Scholars,Grant/Award Number:52022066。
文摘The supercritical CO_(2)(sCO_(2))power cycle could improve efficiencies for a wide range of thermal power plants.The sCO_(2)turbine generator plays an important role in the sCO_(2)power cycle by directly converting thermal energy into mechanical work and electric power.The operation of the generator encounters challenges,including high temperature,high pressure,high rotational speed,and other engineering problems,such as leakage.Experimental studies of sCO_(2)turbines are insufficient because of the significant difficulties in turbine manufacturing and system construction.Unlike most experimental investigations that primarily focus on 100 kW‐or MW‐scale power generation systems,we consider,for the first time,a small‐scale power generator using sCO_(2).A partial admission axial turbine was designed and manufactured with a rated rotational speed of 40,000 rpm,and a CO_(2)transcritical power cycle test loop was constructed to validate the performance of our manufactured generator.A resistant gas was proposed in the constructed turbine expander to solve the leakage issue.Both dynamic and steady performances were investigated.The results indicated that a peak electric power of 11.55 kW was achieved at 29,369 rpm.The maximum total efficiency of the turbo‐generator was 58.98%,which was affected by both the turbine rotational speed and pressure ratio,according to the proposed performance map.
基金This work was supported of National Natural Science Foundation of China Fund(No.52306033)State Key Laboratory of Engines Fund(No.SKLE-K2022-07)the Jiangxi Provincial Postgraduate Innovation Special Fund(No.YC2022-s513).
文摘The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle efficiency.Mathematical models of four Brayton cycle layouts are developed in this study for different reactors to reduce the cost and increase the thermohydraulic performance of nuclear power generation to promote the commercialization of nuclear energy.Parametric analysis,multi-objective optimizations,and four decision-making methods are applied to obtain each Brayton scheme’s optimal thermohydraulic and economic indexes.Results show that for the same design thermal power scale of reactors,the higher the core’s exit temperature,the better the Brayton cycle’s thermo-economic performance.Among the four-cycle layouts,the recompression cycle(RC)has the best overall performance,followed by the simple recuperation cycle(SR)and the intercooling cycle(IC),and the worst is the reheating cycle(RH).However,RH has the lowest total cost of investment(C_(tot))of$1619.85 million,and IC has the lowest levelized cost of energy(LCOE)of 0.012$/(kWh).The nuclear Brayton cycle system’s overall performance has been improved due to optimization.The performance of the molten salt reactor combined with the intercooling cycle(MSR-IC)scheme has the greatest improvement,with the net output power(W_(net)),thermal efficiencyη_(t),and exergy efficiency(η_(e))improved by 8.58%,8.58%,and 11.21%,respectively.The performance of the lead-cooled fast reactor combined with the simple recuperation cycle scheme was optimized to increase C_(tot) by 27.78%.In comparison,the internal rate of return(IRR)increased by only 7.8%,which is not friendly to investors with limited funds.For the nuclear Brayton cycle,the molten salt reactor combined with the recompression cycle scheme should receive priority,and the gas-cooled fast reactor combined with the reheating cycle scheme should be considered carefully.
基金the support from the National Key Research and Development Program of China(Grant No.2022YFE0137200)the Natural Science Basic Research Program of Shaanxi Province,China(Program No.2024JC-YBQN-0381,2023JC-QN-0403)+2 种基金the Natural Science Basic Research Program of Shaanxi Province,China(Program No.2022JC-37)the Innovation Capability Support Program of Shaanxi(Program No.2023-CX-TD31)the Funded by Open Foundation of Shaanxi Key Laboratory of Carbon Dioxide Sequestration and Enhanced Oil Recovery,and the Youth Innovation Team of Shaanxi Universities。
文摘Proppant transport within fractures is one of the most critical tasks in oil,gas and geothermal reservoir stimulation,as it largely determines the ultimate performance of the operating well.Proppant transport in rough fracture networks is still a relatively new area of research and the associated transport mechanisms are still unclear.In this study,representative parameters of rough fracture surfaces formed by supercritical CO_(2) fracturing were used to generate a rough fracture network model based on a spectral synthesis method.Computational fluid dynamics(CFD)coupled with the discrete element method(DEM)was used to study proppant transport in this rough fracture network.To reveal the turning transport mechanism of proppants into branching fractures at the intersections of rough fracture networks,a comparison was made with the behavior within smooth fracture networks,and the effect of key pumping parameters on the proppant placement in a secondary fracture was analyzed.The results show that the transport behavior of proppant in rough fracture networks is very different from that of the one in the smooth fracture networks.The turning transport mechanisms of proppant into secondary fractures in rough fracture networks are gravity-driven sliding,high velocity fluid suspension,and fracture structure induction.Under the same injection conditions,supercritical CO_(2)with high flow Reynolds number still has a weaker ability to transport proppant into secondary fractures than water.Thickening of the supercritical CO_(2)needs to be increased beyond a certain value to have a significant effect on proppant carrying,and under the temperature and pressure conditions of this paper,it needs to be increased more than 20 times(about 0.94 m Pa s).Increasing the injection velocity and decreasing the proppant concentration facilitates the entry of proppant into the branching fractures,which in turn results in a larger stimulated reservoir volume.The results help to understand the proppant transport and placement process in rough fracture networks formed by reservoir stimulation,and provide a theoretical reference for the optimization of proppant pumping parameters in hydraulic fracturing.
文摘An experimental setup for separating ginger essential oil by supercritical fluid extraction is established. The effects of the extraction pressure, temperature, CO2 flow rate and particle size of raw material on the extraction rate are investigated, and the optimum process conditions of supercritical CO2 extraction are determined. A mathematical simulation model is established based on the mass conservation in differential units of extraction bed. The total mass transfer driving force and the equilibrium absorption constant are evaluated by the linear driving force theory. The results from numerical simulation agree well with the experimental data.
基金Supported by the National Natural Science Foundation of China(Nos.20776066, 20976079)
文摘Extraction of heavy metal ions from solid matrix by means of an incorporation of chelating agents with supercritical carbon dioxide（scCO2） was investigated experimentally. Four commercially available chelating agents, diethylammonium diethyldithiocarbamate（Et2NH2DDC）, trifluoroacetylacetone（TFA）, hexafluoroacetylacetone（HFA） and thenoyltrifluoroacetone（TTA） were tested. The extraction experiments were conducted at 50 °C and 1.39×107― 2.80×107 Pa. According to the experimental results, for the extraction of Cu2＋, all the chelating agents investigated here are effective. For other metal ions, such as Pb2＋, Ni2＋ and Cd2＋, Et2NH2DDC exhibited a better extraction result, while other chelating agents were less effective. This investigation is expected to provide a tentative evaluation on the scCO2-based metal extraction from solid media.
基金Supported by National Science and Technology Support Program during the Twelfth Five-Year Plan(2011FJ1047).
文摘[Objectives]This study was conducted to establish a mathematical model for supercritical CO_(2) extraction of curcumin.[Methods]With ginger as the experimental raw material,a quadratic polynomial mathematical model of the yield of curcumin extracted by supercritical CO_(2) was established by response surface methodology(RSM).The validity of the mathematical model was verified,and the effects of extraction temperature(60-70℃),pressure(30-50 MPa)and time(70-90 min)on curcumin yield were analyzed.[Results]According to the model,the process parameters were optimized.Taking curcumin yield as the index,the optimal process conditions for supercritical CO_(2) extraction obtained were:temperature 62.6℃,pressure 37.7 MPa,time 82.9 min,under which the yield of curcumin was as high as 7.34%.Under the optimal extraction conditions,curcumin had a certain reducing capacity,and showed strong scavenging capacities to·OH,O_(2)^(-)·and DPPH,and its IC_(50) values were 9.40,9.03 and 8.04 mg/ml,respectively.Therefore,it is feasible to extract curcumin from ginger using supercritical CO_(2).[Conclusions]This study provides a theoretical basis for the development and utilization of curcumin.
