In this article VLE data for a ternary system (propylene-methanol-water) under 30～60 C,0. 3～0. 9 MPa with a mass ratio of methanol to water of 9:1, 8: 2, 7: 3 were determined with a static equilibrium still, and wer...In this article VLE data for a ternary system (propylene-methanol-water) under 30～60 C,0. 3～0. 9 MPa with a mass ratio of methanol to water of 9:1, 8: 2, 7: 3 were determined with a static equilibrium still, and were correlated by using Peng-Robinson model. The average relative error ofpropylene concentration in liquid phase is 1. 46 %. The results indicate that the models are very suitablefor the ternary system and the data are reliable.展开更多
In order to provide the theoretical guidance for applying the neutralization method to treatment of heavy metals wastewater with high concentration of sulfate, and to better understand the mechanism of calcium sulfate...In order to provide the theoretical guidance for applying the neutralization method to treatment of heavy metals wastewater with high concentration of sulfate, and to better understand the mechanism of calcium sulfate scale formation, the equilibrium solubility data of CaSOa-Ca（OH）2-H2O system at 298.15 K were theoretically calculated via the Pitzer semi-empirical ion-interaction theory, and determined experimentally by the optical method combining with X-ray diffractometry, and the calculated and determined phase diagrams of CaSOa-Ca（OH）2-H2O system were plotted and compared. Physical definition of each area was studied, and the physical law of characteristic point and line was explained in detail. Adjusting the pH value of neutralization-hydrolysis solution depended on the SO4z- concentration in the system. And interaction characteristics between the solubilities of CaSO4（s）and Ca（OH）2（s）were found out.展开更多
The solubilities of the quinary system Na^＋ ,K^＋ ,Mg^2＋ //Cl ,NO 3 ^-H2O and its two quaternary subsystems, Na^＋ ,K^＋ ,Mg^2＋ //NO 3 -H2O and K^ ＋ ,Mg ^2＋ //Cl ,NO 3 ^-H2O,were studied by isothermal method at 2...The solubilities of the quinary system Na^＋ ,K^＋ ,Mg^2＋ //Cl ,NO 3 ^-H2O and its two quaternary subsystems, Na^＋ ,K^＋ ,Mg^2＋ //NO 3 -H2O and K^ ＋ ,Mg ^2＋ //Cl ,NO 3 ^-H2O,were studied by isothermal method at 25°C and their phase diagrams were plotted.In the equilibrium phase diagram of quaternary system Na^ ＋ ,K^ ＋ ,Mg ^2＋ //NO 3 ^-H2O, there are one invariant point,three univariant curves and three regions of crystallization with one salt：NaNO3, KNO3 and Mg（NO3）2·6H2O.In the equilibrium phase diagram of quaternary system K ^＋ ,Mg ^2＋ //Cl ,NO 3 ^-H2O,there are three invariant points,seven univariant curves and five regions of crystallization with one salt：KNO3,KCl, Mg（NO3）2·6H2O,MgCl2·6H2O and KCl·MgCl2·6H2O.In the equilibrium phase diagram of the quinary system Na ^＋ , K^ ＋ ,Mg ^2＋ //Cl ,NO 3^ -H2O,there are four invariant points,and seven regions of crystallization with one salt：NaCl, KCl,NaNO3,KCl·MgCl2·6H2O,KNO3,MgCl2·6H2O and Mg（NO3）2·6H2O.展开更多
The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal so...The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal solution saturation method. The equilibrium solids were also investigated by the Schreinemaker's method of wet residues and X-ray powder diffraction(XRD). According to the experimental data, the phase diagrams were determined. It was found that there was no significant solubility difference on the Na Cl-rich side between the ternary system(Na Cl + Na_2SO_4+ H_2O) in coal gasification wastewater and in pure water. However, the solubility on the Na_2SO_4-rich side of coal gasification wastewater was apparently higher than that of pure water. The increase in the solubility of Na_2SO_4 was most likely caused by the effects of other impurities apart from Na Cl and Na_2SO_4 in coal gasification wastewater. The measured data and phase equilibrium diagrams can provide fundamental basis for salt recovery in coal gasification wastewater.展开更多
To study the feasibility of CO2 geological sequestration,it is needed to understand the complicated mul- tiple-phase equilibrium and the densities of aqueous solution with CO2 and multi-ions under wide geological cond...To study the feasibility of CO2 geological sequestration,it is needed to understand the complicated mul- tiple-phase equilibrium and the densities of aqueous solution with CO2 and multi-ions under wide geological condi- tions(273.15—473.15K,0—60MPa),which are also essential for designing separation equipments in chemical or oil-related industries.For this purpose,studies on the relevant phase equilibria and densities are reviewed and ana- lyzed and the method to improve or modify the existing model is suggested in order to obtain more reliable pre- dictions in a wide temperature and pressure range.Besides,three different models(the electrolyte non random two-liquid(ELECNRTL),the electrolyte NRTL combining with Helgeson model(ENRTL-HG),Pitzer activity co- efficient model combining with Helgeson model(PITZ-HG))are used to calculate the vapor-liquid phase equilib- rium of CO2-H2O and CO2-H2O-NaCl systems.For CO2-H2O system,the calculation results agree with the experi- mental data very well at low and medium pressure(0—20MPa),but there are great discrepancies above 20MPa.For the water content at 473.15K,the calculated results agree with the experimental data quite well.For the CO2-H2O-NaCl system,the PITZ-HG model show better results than ELECNRTL and ENRTL-HG models at the NaCl concentration of 0.52mol·L -1 .Bur for the NaCl concentration of 3.997mol·L -1 ,using the ELECNRTL and ENRTL-HG models gives better results than using the PITZ-HG model.It is shown that available experimental data and the thermodynamic calculations can satisfy the needs of the calculation of the sequestration capacity in the temperature and pressure range for disposal of CO2 in deep saline aquifers.More experimental data and more accu- rate thermodynamic calculations are needed in high temperature and pressure ranges(above 398.15K and 31.5MPa).展开更多
Equilibrium moisture content （EMC） data for rough rice of thirteen Chinese varieties were obtained by static gravimetric method at five different temperatures （10, 20, 25, 30, and 35 ℃） and 11% to 96% equilibrium...Equilibrium moisture content （EMC） data for rough rice of thirteen Chinese varieties were obtained by static gravimetric method at five different temperatures （10, 20, 25, 30, and 35 ℃） and 11% to 96% equilibrium relative humidity （ERH）. Six models, i.e., Brunauer-Emmett-Teller, Guggenheim-Anderson-deBoer, Modified Chung-Pfost （MCPE）, Modified Henderson, Modified Oswin, and Strohman-Yoerger （STYE） fitted the EMC/ERH data based on the coefficient of determination, residue sum-of-squares, standard error of estimate, and mean relative percent error. The best fitted equations were MCPE and STYE, but MCPE is three-parameter, readily transformed equation and adopted in this study. The isosteric heats for both rough rice desorption and adsorption, and for both the sorption of Japonica and Indica rice, decreased rapidly with an increase in seed moisture content （m.c.） until the m.c. of 20% dry basis （d.b.） reached, and thereafter they decreased smoothly with increasing moisture content. The isosteric heats of rough rice desorption were higher than those of adsorption below the m.c. of 22.5% d.b., but thereafter, there was no significant difference found between desorption and adsorption. The sorption isosteric heats of Indica rice were slightly higher than those of Japonica rice under all moisture contents at a constant temperature. These results provide a sound basis for future work on the drying and storage of rice.展开更多
The recovery of contaminants and useful substances from liquid wastes, thepurification of production effluents and the separation of thermally instable mixtures are some ofthe multivarious applications of thin-film di...The recovery of contaminants and useful substances from liquid wastes, thepurification of production effluents and the separation of thermally instable mixtures are some ofthe multivarious applications of thin-film distillers in many processes of the chemical and alliedindustries and of the food industries. In a study carried out in pilot plants with distillation testsystems there was found a good agreement between the experimental separation results and thoseobtained by computing with a theorectical model; the latter is based on the assumption of phaseequilibrium between the vapour formed on an infinitely small element of area in a liquid film of anygiven concentric periphery of the vertically arranged evaporator. These tests were perfomed undervarious phase loads.展开更多
This paper presents an extension of the procedure developed in the case of water-alkane binaries to mixtures of water and benzene or toluene or xylene or ethylbenzene or diethylbenzene. The method used to calculate th...This paper presents an extension of the procedure developed in the case of water-alkane binaries to mixtures of water and benzene or toluene or xylene or ethylbenzene or diethylbenzene. The method used to calculate the equilibria is baized on the Peng-Robinson cubic equation of state modified as regards the coefficient α(Tr) and on the use of a binary interaction coefficient Kiw specific to binaries containing water.展开更多
Numbers of hydrate-based new techniques require the algorithm to be able to perform multiphase flash calculation where one phase is a gas hydrate phase.Tetrahydrofuran(THF)is frequently used as a thermodynamic promote...Numbers of hydrate-based new techniques require the algorithm to be able to perform multiphase flash calculation where one phase is a gas hydrate phase.Tetrahydrofuran(THF)is frequently used as a thermodynamic promoter in the development of hydrate-based technique,which can reduce the hydrate formation pressure,especially when methane or hydrogen exists.However,it is a hard work to describe accurately the phase behavior of THF-water system due to their polarities.It has been proved that the water-in-oil(W/O)emulsion can raise the hydrate formation rate and improve the single stage separation efficiency,and furthermore prevent the hydrate from agglomeration to plug the facilities.The goal of this work is to present an extension of our previous work to the prediction of the vapor-liquid-liquid-hydrate equilibrium of such complex systems.These include ternary and quaternary mixtures with W/O emulsion containing THF.The proposed algorithm of four phase equilibrium calculation is very simple due to avoiding the complexity of simultaneous solution of the sophisticated equation group.The calculation results were found to be in satisfactory agreement with the experimental data.展开更多
文摘In this article VLE data for a ternary system (propylene-methanol-water) under 30～60 C,0. 3～0. 9 MPa with a mass ratio of methanol to water of 9:1, 8: 2, 7: 3 were determined with a static equilibrium still, and were correlated by using Peng-Robinson model. The average relative error ofpropylene concentration in liquid phase is 1. 46 %. The results indicate that the models are very suitablefor the ternary system and the data are reliable.
基金Project (50925417) supported by the Funds for Distinguished Young Scientists of ChinaProject (50830301) supported by the National Natural Science Foundation of ChinaProject (2009ZX07212-001-01) supported by Major Science and Technology Program for Water Pollution Control and Treatment
文摘In order to provide the theoretical guidance for applying the neutralization method to treatment of heavy metals wastewater with high concentration of sulfate, and to better understand the mechanism of calcium sulfate scale formation, the equilibrium solubility data of CaSOa-Ca（OH）2-H2O system at 298.15 K were theoretically calculated via the Pitzer semi-empirical ion-interaction theory, and determined experimentally by the optical method combining with X-ray diffractometry, and the calculated and determined phase diagrams of CaSOa-Ca（OH）2-H2O system were plotted and compared. Physical definition of each area was studied, and the physical law of characteristic point and line was explained in detail. Adjusting the pH value of neutralization-hydrolysis solution depended on the SO4z- concentration in the system. And interaction characteristics between the solubilities of CaSO4（s）and Ca（OH）2（s）were found out.
基金Supported by the National Natural Science Foundation of China（20466003 20866008）
文摘The solubilities of the quinary system Na^＋ ,K^＋ ,Mg^2＋ //Cl ,NO 3 ^-H2O and its two quaternary subsystems, Na^＋ ,K^＋ ,Mg^2＋ //NO 3 -H2O and K^ ＋ ,Mg ^2＋ //Cl ,NO 3 ^-H2O,were studied by isothermal method at 25°C and their phase diagrams were plotted.In the equilibrium phase diagram of quaternary system Na^ ＋ ,K^ ＋ ,Mg ^2＋ //NO 3 ^-H2O, there are one invariant point,three univariant curves and three regions of crystallization with one salt：NaNO3, KNO3 and Mg（NO3）2·6H2O.In the equilibrium phase diagram of quaternary system K ^＋ ,Mg ^2＋ //Cl ,NO 3 ^-H2O,there are three invariant points,seven univariant curves and five regions of crystallization with one salt：KNO3,KCl, Mg（NO3）2·6H2O,MgCl2·6H2O and KCl·MgCl2·6H2O.In the equilibrium phase diagram of the quinary system Na ^＋ , K^ ＋ ,Mg ^2＋ //Cl ,NO 3^ -H2O,there are four invariant points,and seven regions of crystallization with one salt：NaCl, KCl,NaNO3,KCl·MgCl2·6H2O,KNO3,MgCl2·6H2O and Mg（NO3）2·6H2O.
基金Supported by the National Key Research and Development Program of China(2016YFB0600504)
文摘The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal solution saturation method. The equilibrium solids were also investigated by the Schreinemaker's method of wet residues and X-ray powder diffraction(XRD). According to the experimental data, the phase diagrams were determined. It was found that there was no significant solubility difference on the Na Cl-rich side between the ternary system(Na Cl + Na_2SO_4+ H_2O) in coal gasification wastewater and in pure water. However, the solubility on the Na_2SO_4-rich side of coal gasification wastewater was apparently higher than that of pure water. The increase in the solubility of Na_2SO_4 was most likely caused by the effects of other impurities apart from Na Cl and Na_2SO_4 in coal gasification wastewater. The measured data and phase equilibrium diagrams can provide fundamental basis for salt recovery in coal gasification wastewater.
基金Supported by the Chinese National Science Foundation for 0utstanding Young Scholars （No.29925616）, the Joint Research Fund for Young Scholars in Hong Kong and Abroad （No.20428606）, the National Natural Science Foundation of China （Nos.20236010, 20246002, 20376032）, the Natural Science Foundation of Jiangsu Province （Nos.BK2002016, BK2004215） and Chinese National Fundamental Research Development Program （973 Program： 2003CB615700）.
文摘To study the feasibility of CO2 geological sequestration,it is needed to understand the complicated mul- tiple-phase equilibrium and the densities of aqueous solution with CO2 and multi-ions under wide geological condi- tions(273.15—473.15K,0—60MPa),which are also essential for designing separation equipments in chemical or oil-related industries.For this purpose,studies on the relevant phase equilibria and densities are reviewed and ana- lyzed and the method to improve or modify the existing model is suggested in order to obtain more reliable pre- dictions in a wide temperature and pressure range.Besides,three different models(the electrolyte non random two-liquid(ELECNRTL),the electrolyte NRTL combining with Helgeson model(ENRTL-HG),Pitzer activity co- efficient model combining with Helgeson model(PITZ-HG))are used to calculate the vapor-liquid phase equilib- rium of CO2-H2O and CO2-H2O-NaCl systems.For CO2-H2O system,the calculation results agree with the experi- mental data very well at low and medium pressure(0—20MPa),but there are great discrepancies above 20MPa.For the water content at 473.15K,the calculated results agree with the experimental data quite well.For the CO2-H2O-NaCl system,the PITZ-HG model show better results than ELECNRTL and ENRTL-HG models at the NaCl concentration of 0.52mol·L -1 .Bur for the NaCl concentration of 3.997mol·L -1 ,using the ELECNRTL and ENRTL-HG models gives better results than using the PITZ-HG model.It is shown that available experimental data and the thermodynamic calculations can satisfy the needs of the calculation of the sequestration capacity in the temperature and pressure range for disposal of CO2 in deep saline aquifers.More experimental data and more accu- rate thermodynamic calculations are needed in high temperature and pressure ranges(above 398.15K and 31.5MPa).
文摘Equilibrium moisture content （EMC） data for rough rice of thirteen Chinese varieties were obtained by static gravimetric method at five different temperatures （10, 20, 25, 30, and 35 ℃） and 11% to 96% equilibrium relative humidity （ERH）. Six models, i.e., Brunauer-Emmett-Teller, Guggenheim-Anderson-deBoer, Modified Chung-Pfost （MCPE）, Modified Henderson, Modified Oswin, and Strohman-Yoerger （STYE） fitted the EMC/ERH data based on the coefficient of determination, residue sum-of-squares, standard error of estimate, and mean relative percent error. The best fitted equations were MCPE and STYE, but MCPE is three-parameter, readily transformed equation and adopted in this study. The isosteric heats for both rough rice desorption and adsorption, and for both the sorption of Japonica and Indica rice, decreased rapidly with an increase in seed moisture content （m.c.） until the m.c. of 20% dry basis （d.b.） reached, and thereafter they decreased smoothly with increasing moisture content. The isosteric heats of rough rice desorption were higher than those of adsorption below the m.c. of 22.5% d.b., but thereafter, there was no significant difference found between desorption and adsorption. The sorption isosteric heats of Indica rice were slightly higher than those of Japonica rice under all moisture contents at a constant temperature. These results provide a sound basis for future work on the drying and storage of rice.
文摘The recovery of contaminants and useful substances from liquid wastes, thepurification of production effluents and the separation of thermally instable mixtures are some ofthe multivarious applications of thin-film distillers in many processes of the chemical and alliedindustries and of the food industries. In a study carried out in pilot plants with distillation testsystems there was found a good agreement between the experimental separation results and thoseobtained by computing with a theorectical model; the latter is based on the assumption of phaseequilibrium between the vapour formed on an infinitely small element of area in a liquid film of anygiven concentric periphery of the vertically arranged evaporator. These tests were perfomed undervarious phase loads.
文摘This paper presents an extension of the procedure developed in the case of water-alkane binaries to mixtures of water and benzene or toluene or xylene or ethylbenzene or diethylbenzene. The method used to calculate the equilibria is baized on the Peng-Robinson cubic equation of state modified as regards the coefficient α(Tr) and on the use of a binary interaction coefficient Kiw specific to binaries containing water.
基金supports received from the National Natural Science Foundation of China(20925623,U1162205)National Basic Research Program of China(973 Project,2012CB215005)
文摘Numbers of hydrate-based new techniques require the algorithm to be able to perform multiphase flash calculation where one phase is a gas hydrate phase.Tetrahydrofuran(THF)is frequently used as a thermodynamic promoter in the development of hydrate-based technique,which can reduce the hydrate formation pressure,especially when methane or hydrogen exists.However,it is a hard work to describe accurately the phase behavior of THF-water system due to their polarities.It has been proved that the water-in-oil(W/O)emulsion can raise the hydrate formation rate and improve the single stage separation efficiency,and furthermore prevent the hydrate from agglomeration to plug the facilities.The goal of this work is to present an extension of our previous work to the prediction of the vapor-liquid-liquid-hydrate equilibrium of such complex systems.These include ternary and quaternary mixtures with W/O emulsion containing THF.The proposed algorithm of four phase equilibrium calculation is very simple due to avoiding the complexity of simultaneous solution of the sophisticated equation group.The calculation results were found to be in satisfactory agreement with the experimental data.
