The separation characteristics of the PVA-CS (polyvinyl alcohol-chitosan) blended composite membrane for dehydration of ethanol-water mixture are examined. The relationships of flux and separation factor with the feed...The separation characteristics of the PVA-CS (polyvinyl alcohol-chitosan) blended composite membrane for dehydration of ethanol-water mixture are examined. The relationships of flux and separation factor with the feed concentration and operation temperature are established. Using this correlated equation, the continuous-flow pervaporation process about 500 kilolitres/year dehydrated ethanol is designed. The numbers of stage and reheater are calculated by stage-by-stage method for two kinds of cascades: one with equal membrane area and the other with 10℃ of temperature decrement per section. The results show that when the numbers of stage and reheater are the same, the cascade with 10℃ of temperature decrement has more advantages than that with equal membrane area. The influences of feed concentration and flow rate on the numbers of stage and reheater in the cascades are discussed.展开更多
Hirudin is the most anticoagulant drug found in nature, but its short serum half-life significantly inhibits its clinical anpplication. The PEGvlation of hirudin, the most promising anticoagulant drug, was performed i...Hirudin is the most anticoagulant drug found in nature, but its short serum half-life significantly inhibits its clinical anpplication. The PEGvlation of hirudin, the most promising anticoagulant drug, was performed in this paper. The optimal reaction conditions for PEG ylated hirudin were investigated, wh.en the PEGylation react, on.wasconducted under 4℃ after 10h, in the borate buffer at pH 8.5 .with the molar ratio 230 ： 1 of PEG to hirudin, a higher modification extent was achieved. Finally, the bioactivity of PEGylated hirudin was measured in vitro.Compared with unmodified hirudin, 26% of anti-thrombin activity was retained.展开更多
Four empirical models are tested for fitting the T-y-x equilibrium data of ethanol-water mixture by minimizing the Root Mean Square （RMS） between equilibrium data and theoretical points. The total pressure of the co...Four empirical models are tested for fitting the T-y-x equilibrium data of ethanol-water mixture by minimizing the Root Mean Square （RMS） between equilibrium data and theoretical points. The total pressure of the correspondent data is 101.3 kPa. All models parameters are also identified. The study suggests that NRTL model fits the equilibrium data best with RMS = 0.4 %.展开更多
This study investigated the prospect of using aqueous mixture of 1-butylpyridinium tetrafluoroborate （[Bpy][BF4]） ionic liquid （IL） and monoethanolamine （MEA） as solvent in post-combustion CO2 capture （PCC） pr...This study investigated the prospect of using aqueous mixture of 1-butylpyridinium tetrafluoroborate （[Bpy][BF4]） ionic liquid （IL） and monoethanolamine （MEA） as solvent in post-combustion CO2 capture （PCC） process. This is done by analysis of the process through modelling and simulation. In literature, reported PCC models with a mixture of IL and MEA solvent were developed using equilibrium-based mass transfer approach. In contrast, the model in this study is developed using rate-based mass transfer approach in Aspen Plus. From the results, the mixed aqueous solvent with 5-30 wt% IL and 30 wt% MEA showed 7%-9% and 12%-27% less specific regeneration energy and solvent circulation rate respectively compared to commonly used 30 wt% MEA solvent. It is concluded that the ｜L concentration （wt%） in the solvent blend have significant impact on specific regeneration energy and solvent circulation rate. This study is a starting point for further research on technical and economic analysis of PCC process with aqueous blend of IL and MEA as solvent.展开更多
基金Supported by the National Natural Science Foundation of China(No.29836160) and Commission of Science & Technology of Zhejiang Province(No.924010,No.85-12-02-05).
文摘The separation characteristics of the PVA-CS (polyvinyl alcohol-chitosan) blended composite membrane for dehydration of ethanol-water mixture are examined. The relationships of flux and separation factor with the feed concentration and operation temperature are established. Using this correlated equation, the continuous-flow pervaporation process about 500 kilolitres/year dehydrated ethanol is designed. The numbers of stage and reheater are calculated by stage-by-stage method for two kinds of cascades: one with equal membrane area and the other with 10℃ of temperature decrement per section. The results show that when the numbers of stage and reheater are the same, the cascade with 10℃ of temperature decrement has more advantages than that with equal membrane area. The influences of feed concentration and flow rate on the numbers of stage and reheater in the cascades are discussed.
文摘Hirudin is the most anticoagulant drug found in nature, but its short serum half-life significantly inhibits its clinical anpplication. The PEGvlation of hirudin, the most promising anticoagulant drug, was performed in this paper. The optimal reaction conditions for PEG ylated hirudin were investigated, wh.en the PEGylation react, on.wasconducted under 4℃ after 10h, in the borate buffer at pH 8.5 .with the molar ratio 230 ： 1 of PEG to hirudin, a higher modification extent was achieved. Finally, the bioactivity of PEGylated hirudin was measured in vitro.Compared with unmodified hirudin, 26% of anti-thrombin activity was retained.
文摘Four empirical models are tested for fitting the T-y-x equilibrium data of ethanol-water mixture by minimizing the Root Mean Square （RMS） between equilibrium data and theoretical points. The total pressure of the correspondent data is 101.3 kPa. All models parameters are also identified. The study suggests that NRTL model fits the equilibrium data best with RMS = 0.4 %.
文摘This study investigated the prospect of using aqueous mixture of 1-butylpyridinium tetrafluoroborate （[Bpy][BF4]） ionic liquid （IL） and monoethanolamine （MEA） as solvent in post-combustion CO2 capture （PCC） process. This is done by analysis of the process through modelling and simulation. In literature, reported PCC models with a mixture of IL and MEA solvent were developed using equilibrium-based mass transfer approach. In contrast, the model in this study is developed using rate-based mass transfer approach in Aspen Plus. From the results, the mixed aqueous solvent with 5-30 wt% IL and 30 wt% MEA showed 7%-9% and 12%-27% less specific regeneration energy and solvent circulation rate respectively compared to commonly used 30 wt% MEA solvent. It is concluded that the ｜L concentration （wt%） in the solvent blend have significant impact on specific regeneration energy and solvent circulation rate. This study is a starting point for further research on technical and economic analysis of PCC process with aqueous blend of IL and MEA as solvent.
