The solubilities and the refractive indices of the saturated solution in the system C 6H 12 O 6 NH 4Cl C 2H 5OH-H 2O ( C 2H 5OH / H 2O=0.90, by wt ) at 35℃ have been determined. The isotherms and r...The solubilities and the refractive indices of the saturated solution in the system C 6H 12 O 6 NH 4Cl C 2H 5OH-H 2O ( C 2H 5OH / H 2O=0.90, by wt ) at 35℃ have been determined. The isotherms and refractive indices of the system at 35℃ consist of 2 branches, corresponding to C 6H 12 O 6( H 2O and NH 4Cl. The composition of eutectic solution is C 6H 12 O 6: 4.40 %, NH 4Cl: 13.86 %, C 2H 5OH: 38.88 %.展开更多
A stripping batch distillation column is preferred when the amount of the light component in the feed is small and the products are to be recovered at high purity. The operation modes of a batch stripping are believed...A stripping batch distillation column is preferred when the amount of the light component in the feed is small and the products are to be recovered at high purity. The operation modes of a batch stripping are believed to be the same as those of a rectifier. However, the control system of a stripper is different. In this paper, we explore three different control methods with Hysys (Hyprotech Ltd. 1997) for a batch stripper. The main difference is the control scheme for reboiler liquid level: (a) controlled by reflux flow; (b) controlled by reboiler heat duty; (c) controlled by bottom product flow. The main characteristics of operating a batch stripper with different control scheme are presented in this paper. Guidelines are provided for the startup of a batch stripper, the effects of somecontrol tuning parameters on the column performance are discussed.展开更多
Considering that the on-line measurement and automatic control of element component content(ECC) are difficult to perform in rare earth cascade extraction process, the ECC distribution profile is dynamically regulated...Considering that the on-line measurement and automatic control of element component content(ECC) are difficult to perform in rare earth cascade extraction process, the ECC distribution profile is dynamically regulated at all stages to assess the effect of product purity control. Focusing on the theory of countercurrent extraction, the technology parameters and pre-setting flow-rates during the extract process are designed. Under varying process parameters, a novel step by step model is also proposed for each stage to analyze the impact on the distribution profile change. Combining the mass balance model and ECC changing trend at the monitoring stage, the ECC distribution profile can be automatically regulated by dynamically compensating the related extract or scrubbing liquid flow-rate. To this end, the required product purity at the two outlets is achieved. Based on Wincc and Matlab dynamic simulators, a specific Pr/Nd cascade extraction process is used to illustrate and demonstrate the application of the present approach.展开更多
This paper shows some generalities about the glycerin byproduct obtained from biodiesel production process, presents an analysis of the ternary equilibrium between methanol, water and glycerol, and shows the influence...This paper shows some generalities about the glycerin byproduct obtained from biodiesel production process, presents an analysis of the ternary equilibrium between methanol, water and glycerol, and shows the influence that temperature has on the balance. This phase diagram illustrates ternary equilibrium at 10, 20 and 50 ℃, keeping the pressure constant at 1 atm （atmosphere） to standardize the analysis. The purpose of it is to establish the best temperature for the purification of glycerol by liquid-liquid extraction method under the ＂extraction in several stages cross flow＂ taking an initial mixture of glycerol with composition 15 wt.% water, 25 wt.% methanol and 60 wt.% glycerol. Water was used as liquid-liquid extraction solvent in order to remove as much methanol as possible from the initial solution due to the existence of a zone of insolubility between the glycerol and water in the ternary equilibrium. By this reason, two solutions are obtained, one consisting of water and methanol containing a trace of glycerin and the other consisting of water, glycerine and traces of methanol, which contain only 4.62% of the total methanol which enter in the process of liquid-liquid extraction, with 60.62% of the total glycerol, which is sent to a fractional distillation process to purify glycerin up to 98% by weight.展开更多
In the present study, we described a novel, simple, and scalable method for isolating and purifying natural mangiferin from fresh mango leaves. An ultrasonic-assisted method was used to extract mangiferin from mango l...In the present study, we described a novel, simple, and scalable method for isolating and purifying natural mangiferin from fresh mango leaves. An ultrasonic-assisted method was used to extract mangiferin from mango leaves using methanol as the solvent. The yields of the mangiferin crude extract and purified mangiferin recrystallized from a mixture of methanol and trichloromethane(10:1, v/v) were 1.41%(purity 86.5%) and 0.75%(purity > 99.6%), respectively. The purity of mangiferin was assessed by UV spectroscopy and HPLC. The structure of the purified compound was confirmed spectroscopically by UV, IR, Q-TOF/MS,;H NMR, and;C NMR. The method described herein to isolate mangiferin was simple, inexpensive, rapid, and efficient. Moreover, we, for the first time, obtained mangiferin with a purity of more than 99.6% using this method.展开更多
文摘The solubilities and the refractive indices of the saturated solution in the system C 6H 12 O 6 NH 4Cl C 2H 5OH-H 2O ( C 2H 5OH / H 2O=0.90, by wt ) at 35℃ have been determined. The isotherms and refractive indices of the system at 35℃ consist of 2 branches, corresponding to C 6H 12 O 6( H 2O and NH 4Cl. The composition of eutectic solution is C 6H 12 O 6: 4.40 %, NH 4Cl: 13.86 %, C 2H 5OH: 38.88 %.
基金Supported by CONICET (Consejo Nacional de Investigaciones Cientificas y Tecnicas, Argentina) (No. 778) and the Scientific Research Foundation of the State Education Ministry for Returned Overseas Chinese Scholar.
文摘A stripping batch distillation column is preferred when the amount of the light component in the feed is small and the products are to be recovered at high purity. The operation modes of a batch stripping are believed to be the same as those of a rectifier. However, the control system of a stripper is different. In this paper, we explore three different control methods with Hysys (Hyprotech Ltd. 1997) for a batch stripper. The main difference is the control scheme for reboiler liquid level: (a) controlled by reflux flow; (b) controlled by reboiler heat duty; (c) controlled by bottom product flow. The main characteristics of operating a batch stripper with different control scheme are presented in this paper. Guidelines are provided for the startup of a batch stripper, the effects of somecontrol tuning parameters on the column performance are discussed.
基金Supported by the National Natural Science Foundation of China(51174091,61164013,61364013)
文摘Considering that the on-line measurement and automatic control of element component content(ECC) are difficult to perform in rare earth cascade extraction process, the ECC distribution profile is dynamically regulated at all stages to assess the effect of product purity control. Focusing on the theory of countercurrent extraction, the technology parameters and pre-setting flow-rates during the extract process are designed. Under varying process parameters, a novel step by step model is also proposed for each stage to analyze the impact on the distribution profile change. Combining the mass balance model and ECC changing trend at the monitoring stage, the ECC distribution profile can be automatically regulated by dynamically compensating the related extract or scrubbing liquid flow-rate. To this end, the required product purity at the two outlets is achieved. Based on Wincc and Matlab dynamic simulators, a specific Pr/Nd cascade extraction process is used to illustrate and demonstrate the application of the present approach.
文摘This paper shows some generalities about the glycerin byproduct obtained from biodiesel production process, presents an analysis of the ternary equilibrium between methanol, water and glycerol, and shows the influence that temperature has on the balance. This phase diagram illustrates ternary equilibrium at 10, 20 and 50 ℃, keeping the pressure constant at 1 atm （atmosphere） to standardize the analysis. The purpose of it is to establish the best temperature for the purification of glycerol by liquid-liquid extraction method under the ＂extraction in several stages cross flow＂ taking an initial mixture of glycerol with composition 15 wt.% water, 25 wt.% methanol and 60 wt.% glycerol. Water was used as liquid-liquid extraction solvent in order to remove as much methanol as possible from the initial solution due to the existence of a zone of insolubility between the glycerol and water in the ternary equilibrium. By this reason, two solutions are obtained, one consisting of water and methanol containing a trace of glycerin and the other consisting of water, glycerine and traces of methanol, which contain only 4.62% of the total methanol which enter in the process of liquid-liquid extraction, with 60.62% of the total glycerol, which is sent to a fractional distillation process to purify glycerin up to 98% by weight.
基金The Key R&D projects in Hainan Province (Grant No. ZDYF2020160)the National Key Research and Development Project of China (Grant No. 2017YFF0207800)Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences (Grant No. 1630082017001)。
文摘In the present study, we described a novel, simple, and scalable method for isolating and purifying natural mangiferin from fresh mango leaves. An ultrasonic-assisted method was used to extract mangiferin from mango leaves using methanol as the solvent. The yields of the mangiferin crude extract and purified mangiferin recrystallized from a mixture of methanol and trichloromethane(10:1, v/v) were 1.41%(purity 86.5%) and 0.75%(purity > 99.6%), respectively. The purity of mangiferin was assessed by UV spectroscopy and HPLC. The structure of the purified compound was confirmed spectroscopically by UV, IR, Q-TOF/MS,;H NMR, and;C NMR. The method described herein to isolate mangiferin was simple, inexpensive, rapid, and efficient. Moreover, we, for the first time, obtained mangiferin with a purity of more than 99.6% using this method.
