检索结果-内蒙古大学图书馆

Performance evaluation of silica membrane for water-n-butanol binary mixture

SEPARATION AND PURIFICATION TECHNOLOGY 2014年 127卷 18-28页

作者： Boutikos, Panagiotis Pereira, Carla S. M. Silva, Viviana M. T. M. Rodrigues, Alirio E. Univ Porto Fac Engn Dept Engn Quim LSRE Lab Separat & React EngnAssociate Lab LSRE P-4200465 Oporto Portugal

The pervaporation performance of a commercial silica membrane (Pervatech BV) was evaluated for dehydration of aqueous n-butanol solutions. The influence of the operation parameters, such as feed composition, temperature and permeate pressure was experimentally investigated in terms of permeation flux, separation factor, permeance and membrane selectivity. The membrane exhibited high flux, 3.53 kg/ m(2) h, combined with a separation factor equal to 150, at 70 degrees C and for 10 wt.% water in feed. The mole fraction of water in the permeate ranged from 98.7% to 99.2% at 70 degrees C. The information collected is of most importance to design and optimize a pervaporation process for the dehydration of n-butanol, which can be integrated with an intensified technology, the simulated moving bed reactor, used in the synthesis of the green fuel, 1,1-dibutoxyethane. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Silica membrane Pervaporation Water-butanol mixture solution-diffusion model Activation energy

来源：评论

学校读者我要写书评

暂无评论

A Modified solution-diffusion model and Its Application in the Pervaporation Separation of Benzene/Cyclohexane Mixtures in PDMS Membrane

引用

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 2009年第9期42卷 640-647页

作者： Chen, Jian Huang, Junqi Li, Jiding Zhan, Xia Chen, Cuixian Tsinghua Univ Dept Chem Engn Beijing 10084 Peoples R China

In this paper, a modified solution-diffusion model is proposed to account for the mass transport of penetrants in the polymer membrane. In the model, the group contribution method (the UNIFAC-ZM model) is introduced to calculate the activity of penetrants in the polymer membrane, and a new temperature-dependence diffusion coefficient equation is developed to describe the diffusion behavior of the penetrants. The aim of this work is to establish a predictive solution-diffusion model. By refitting the group interaction parameters based on pervaperation data of penetrants-membrane systems, the model can be applied to predict the fluxes and separation factors of various polymer membrane systems. As an exemplary application of the model, the permeation fluxes and separation factors of benzene/cyclohexane mixtures in a PDMS membrane system have been predicted and shown to be in good agreement with experimental values.

关键词： solution-diffusion model Group Contribution Method Pervaporation Membrane

来源：评论

学校读者我要写书评

暂无评论

Gas transport through cork: modelling gas permeation based on the morphology of a natural polymer material

引用

JOURNAL OF MEMBRANE SCIENCE 2013年 428卷 52-62页

作者： Brazinha, Carla Fonseca, Ana P. Pereira, Helena Teodoro, Orlando M. N. D. Crespo, Joao G. Univ Nova Lisboa FCT Dept Chem REQUIMTE CQFB P-2829516 Caparica Portugal Univ Nova Lisboa FCT Dept Phys CEFITECCtr Phys & Technol Res P-2829516 Caparica Portugal Univ Tecn Lisboa Inst Super Agron Ctr Estudos Florestais P-1100 Lisbon Portugal

Natural polymers have been studied during the last years for the transport and separation of liquid and gas mixtures, in terms of solubility and permeability data, and their structure and mechanical properties have been characterised. However, no transport models have been reported, relating transport with the material morphology. Cork is a natural cellular material containing three structural polymers (suberin, lignin and polysaccharides). Cork is considered a natural polymer, with economic relevance due to its sealing, non-toxic, stable and low-density properties. Cork was characterised in this work in terms of its solubility and permeability data in relation to various gases with different molecular mass: He, O-2, N-2, CO2 and 1,1,1,2-tetrafluoroethane (R134a). A morphological analysis of the structure of the cork sample chosen in this work was also performed using SEM (scanning electron microscopy) and TEM (transmission electron microscope) image analysis, which took into account the variation of each relevant structural parameter. A transport model was developed supported on the morphology of cork characterised in this work. The transport model developed considers that gas permeation occurs through the plasmodesmata, which are channels with approximately 100 nm of diameter that cross the cell walls of the cork cells. It was found that gas transport follows a Knudsen mechanism, as proved by the gas permeability behaviour with increasing gas molecular mass, with a negligible contribution of viscous transport to the total flux. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Gas permeation Cork Natural polymers Solubility Knudsen transport solution-diffusion model

来源：评论

学校读者我要写书评

暂无评论

MOISTURE TRANSPORT THROUGH NON-POROUS HYDROPHILIC MEMBRANES USED IN PROTECTIVE CLOTHING

引用

THERMAL SCIENCE 2013年第5期17卷 1293-1298页

作者： Zhu, Fang-Long Zhou, Yu He, Jian-Xin Zhongyuan Univ Technol Coll Clothing Zhengzhou Peoples R China Donghua Univ Coll Text Shanghai Peoples R China

The three-step upright cup method was employed to determine the total moisture transfer resistance and the two air layer resistances on both sides of the membrane. The effective moisture diffusion coefficient in air layer between the membrane and water surface was determined by the regressive method, and the effective moisture diffusion coefficient of membrane was calculated Experiments were conducted on a non-porous hydrophilic thermoplastic polyester elastomer membrane. The moisture transfer process through the membrane was modeled by using the solution-diffusion model. The effects of membrane microstructure on membrane permeation were analyzed based on the solution-diffusion model and experimental data. The results show that the effective diffusion coefficient can be used to evaluate the mass transfer process through the non-porous hydrophilic thermoplastic polyester elastomer membrane.

关键词： moisture transport diffusion coefficient non-porous hydrophilic membrane solution-diffusion model

来源：评论

学校读者我要写书评

暂无评论

Experimental investigation, modeling and scale-up of hydrophilic vapor permeation membranes: Separation of azeotropic dimethyl carbonate/methanol mixtures

引用

SEPARATION AND PURIFICATION TECHNOLOGY 2013年 118卷 862-878页

作者： Holtbruegge, Johannes Wierschem, Matthias Steinruecken, Simon Voss, Dorothea Parhomenko, Lubow Lutze, Philip TU Dortmund Univ Dept Biochem & Chem Engn Lab Fluid Separat D-44227 Dortmund Germany

The separation of azeotropic mixtures is a challenging task that is currently performed by special distillation processes, such as heteroazeotropic, extractive or pressure-swing distillation. In recent years, membrane materials that are used to separate different combinations of chemical compounds have constituted an energy-efficient and competitive alternative to special distillation processes. Vapor permeation is a promising type of membrane separation processes which enables to overcome limitations caused by the thermodynamic phase equilibrium. This characteristic facilitates the separation of azeotropic mixtures. However, the membrane needs to be large to handle high throughputs or to achieve high purities. Thus, the use of membranes in combination with established unit operations in so-called membrane-assisted separation processes is advantageous. Nevertheless, in addition to the reliable selection of a suitable membrane polymer for a given design task, a model-based scale-up is still challenging and complicates the design of said membrane separations. These disadvantages limit the application of vapor permeation in the chemical industry. Therefore, the aim of this paper is to enable scale-up by systematically identifying the influence of vapor permeation operating parameters at two different experimental scales with a scale-up factor of 50. Based on these experiments, a rigorous model was developed using experimental data from lab-scale to predict the separation characteristics in pilot-scale. These findings were validated against experimental data from this scale. In this work, the separation of dimethyl carbonate and methanol showing a low-boiling azeotrope with high methanol content was used as a case study. The separation of these two compounds is of significant interest because valuable dimethyl carbonate is usually produced from methanol feedstocks, thus necessitating the separation of both components. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Azeotropic separation Lab-scale Pilot-scale PERVAP (TM) solution-diffusion model

来源：评论

学校读者我要写书评

暂无评论

Reverse Osmosis Performance of Organosilica Membranes and Comparison with the Pervaporation and Gas Permeation Properties

引用

AICHE JOURNAL 2013年第4期59卷 1298-1307页

作者： Xu, Rong Wang, Jinhui Kanezashi, Masakoto Yoshioka, Tomohisa Tsuru, Toshinori Hiroshima Univ Dept Chem Engn Higashihiroshima 7398527 Japan

Hybrid organosilica membranes were successfully prepared using bis(triethoxysilyl)ethane (BTESE) and applied to reverse osmosis (RO) desalination. The organosilica membrane calcined at 300 degrees C almost completely rejected salts and neutral solutes with low-molecular-weight. Increasing the operating pressure led to an increase in water flux and salt rejection, while the flux and rejection decreased as salt concentration increased. The water permeation mechanism differed from the viscous flow mechanism. Observed activation energies for permeation were larger for membranes with a smaller pore size, and were considerably larger than the activation energy for water viscosity. The organosilica membranes exhibited exceptional hydrothermal stability in temperature cycles up to 90 degrees C. The applicability of the generalized solution-diffusion (SD) model to RO and pervaporation (PV) desalination processes were examined, and the quantitative differences in water permeance were accurately predicted by the application of generalized transport equations. (C) 2012 American Institute of Chemical Engineers AIChE J, 59: 1298-1307, 2013

关键词： reverse osmosis membrane organosilica solution-diffusion model pervaporation

来源：评论

学校读者我要写书评

暂无评论

A Modified solution-diffusion model and Its Application in the Pervaporation Separation of Alkane/Thiophenes Mixtures with PDMS Membrane

引用

JOURNAL OF APPLIED POLYMER SCIENCE 2008年第5期110卷 3140-3148页

作者： Huang, Junqi Li, Jiding Zhan, Xia Chen, Cuixian Tsinghua Univ Dept Chem Engn Beijing 100084 Peoples R China

A better understanding of the mass transfer in pervaporation membranes under different conditions is essential for both the design of improved membranes in various applications, and for the process design. In this article, a modified solution-diffusion model is proposed to account for the mass transport of penetrants in the polymer membrane. In the model, the group contribution method (the UNIFAC-ZM model) is first introduced to calculate the activity of penetrants in the polymer membrane, and a modified Fujita diffusion coefficient equation is developed to describe the diffusion behavior of the penetrants. The aim of this work is to establish a predictive solution-diffusion model. By refitting the group interaction parameters based on pervaperation data of penetrants-membrane systems, the model can be applied to predict the flux and separation factor of various polymer membrane systems. As an exemplary application of the model, the permeation fluxes and separation factors of alkane/thiophene and alkane/2-methyl-thiophene mixtures in polydimethylsiloxane (PDMS) membrane system have been predicted and showed to be in good agreement with experimental values. (c) 2008 Wiley Periodicals, Inc.

关键词： pervaporation solution-diffusion model group contribution method

来源：评论

学校读者我要写书评

暂无评论

Tailoring bi-soft segment poly (ester urethane urea) integral asymmetric membranes for CO₂ and O₂ permeation

引用

JOURNAL OF MEMBRANE SCIENCE 2012年第1期387卷 66-75页

作者： Faria, Monica Rajagopalan, Mahendran de Pinho, Maria Norberta Univ Tecn Lisboa Inst Super Tecn ICEMS P-1049001 Lisbon Portugal Univ Tecn Lisboa Inst Super Tecn Dept Chem & Biol Engn P-1049001 Lisbon Portugal

Integral asymmetric bi-soft segment poly (ester urethane urea) membranes are casted through a novel procedure where a reaction is introduced in the casting solutions preparation step of the phase inversion technique. Two reactive pre-polymers, the polypropylene oxide-based with three terminal isocyanate groups and the polycaprolactone diol with two terminal hydroxyl groups, are dissolved in a single solvent, dimethyl formamide and in a solvent mixture of dimethyl formamide (DMF)/diethyl ether (DEE) and the polymerization reaction is carried out in a homogeneous phase. The weight ratio of DMF/DEE is varied over 11,5 and 3. The membrane casting is carried out at solvent evaporation times of 30 s, 60 s and 90s. For all the membranes prepared, the cross-sections of the scanning electron microscopy (SEM) images display asymmetric structures dependent on the casting solutions composition and on the casting evaporation times. The carbon dioxide and oxygen volumetric fluxes measured at pressures ranging from 76 cmHg to 380 cmHg were correlated to the active layer thickness of the asymmetric membranes. The achievement of increasing the O-2 and the CO2 permeation rates is the result of the casting of poly (ester urethane urea) asymmetric membranes with the minimization of the thickness of the dense layers. This is coupled with the introduction of the reactive caprolactone pre-polymer that enhances hemocompatibility. These are two strong assets for membrane blood oxygenators. (C) 2011 Elsevier B.V. All rights reserved.

关键词： Bi-soft segment poly (ester urethane urea) Gas permeation Membrane structure/morphology solution-diffusion model Active layer thickness

来源：评论

学校读者我要写书评

暂无评论

Investigation of Mass Transfer in Organic Solvent Nanofiltration Membranes

引用

Procedia Engineering 2012年 44卷 302-303页

作者： J. Micovic L. Hesse P. Schmidt P. Lutze G. Sadowski A. Górak TU Dortmund University Germany

来源：评论

学校读者我要写书评

暂无评论

modeling of Aniline Removal by Reverse Osmosis Using Different Membranes

引用

CHEMICAL ENGINEERING & TECHNOLOGY 2011年第10期34卷 1753-1759页

作者： Hidalgo, Asuncion M. Leon, Gerardo Gomez, Maria Murcia, Maria D. Gomez, Elisa Gomez, Jose L. Univ Murcia Dept Chem Engn E-30071 Murcia Spain Univ Cartagena Chem Engn & Environm Dept Cartagena Colombia

The behavior of different reverse osmosis membranes, namely, HR98PP, SEPA-MS05, and DESAL-3B, was compared with the one predicted by a solution-diffusion model. This model assumes that the membrane has a homogeneous, nonporous surface layer and uses two main parameters, permeate concentration C-p and volumetric permeate flux Q(p), to characterize the membrane system. In order to calculate these parameters, the theoretical values of water and solute permeability constants, A(w) and B-s, and the osmotic pressure coefficient, Psi, were initially determined. Using the software Sigma Plot V 10.0, accurate values of Psi, Q(p), and C-p were only obtained for the DESAL-3B membrane, i.e., the selected solution-diffusion model can be applied to this membrane.

关键词： Aniline Membrane processes Reverse osmosis solution-diffusion model

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：