Pervaporation characteristics

Inui K, Noguchi K, Miyata T, and Uragami T. Pervaporation characteristics of methyl methacrylate-methacrylic acid copolymer membranes ionically crosslinked with metal ions for a benzene/cyclohexane mixture. J Appl Polym Sci 1999 71 233-241. 

S.J. Lue and S.H. Peng, Polyurethane (PU) membrane preparation with and without hydroxylpropyl-P-cyclodextrin and their pervaporation characteristics, J. Membr. Sci., 222 (2003) 203-217. 

Uragami, T., Tsukamoto, K., Inui, K. and Miyata, T. 1998. Pervaporation characteristics of a benzoylchitosan membrane for benzene-cyclohexane mixtures. 

Pandey L.K., Saxena C., Dubey V, Studies on pervaporative characteristics of bacterial cellulose membrane. Separation and Purification Technology, 42, 2005, 213. 

Cao, S. G., Shi, Y. Q., and Chen, G. W. 1999. Properties and pervaporation characteristics of chitosan-poly(A-vinyl-2-pyrrolidone)blend membranes for MeOH-MTBE. J. Appl. Polym. Sci. 74 1452-1458. 

This chapter has studied the control of a column-pervaporation process for producing high-purity ethanol to overcome the azeotropic limitation encountered in distillation. A conventional control structure is developed that provides effective dismrbance rejection for both production rate and feed composition changes. A simple pervaporation model is developed in Aspen Custom Modeler that captures the important dynamic features of the process. The model uses pervaporation characteristic performance curves to determine diffusivities. Component fluxes depend upon composition driving forces between the retentate and permeate sides of the membrane. The dynamics of the pervaporation cells are assumed to be dominated by composition and energy capacitance of the liquid retentate. 

Solak, E.K., Asman, G., famurlu, P., and ganli, O. (2008) Sorption, diffusion, and pervaporation characteristics of dimethylformamide/water mixtures using sodium alginate/polyvinyl pyrrolidone blend membrane. Vacuum, 82, 579-587. 

An important characteristic of pervaporation that distinguishes it from distillation is that it is a rate process, not an equilibrium process. The more permeable component may be the less-volatile component. Perv oration has its greatest iitihty in the resolution of azeotropes, as an acqiinct to distillation. Selecting a membrane permeable to the minor corTiponent is important, since the membrane area required is roughly proportional to the mass of permeate. Thus pervaporation devices for the purification of the ethanol-water azeotrope (95 percent ethanol) are always based on a hydrophihc membrane. 

A very high separation factor has been obtained in phenol dehydration by using pervaporation process and PVA/PAA as membranes. The membrane composition and the process characteristics are presented in table 1. 

Table 1. Characteristics of the separation process by pervaporation function of the membrane composition and structure, composition of feed mixture and temperature [18]...

Table 2. The characteristics of the iso-propanol (IPA) dehydration process, by using pervaporation technique, through (PAA.HCl)-PVA membrane...

Novel hydrophilic polymer membranes based on crosslinked poly(allylamine hydrochloride) (PAA.HCl)-PVA have been developed in order to dehydrate different organic compounds by pervaporation [33], The characteristics of the acetone dehydration process,... 

PVA-PAcr.Ac. membranes have been tested also for ethanol separation from ethanol/toluene mixture, by using pervaporation technique. The reported data concerning the separation process characteristics are presented in table 8. 

The catalytic esterification of ethanol and acetic acid to ethyl acetate and water has been taken as a representative example to emphasize the potential advantages of the application of membrane technology compared with conventional distillation [48], see Fig. 13.6. From the McCabe-Thiele diagram for the separation of ethanol-water mixtures it follows that pervaporation can reach high water selectivities at the azeotropic point in contrast to the distillation process. Considering the economic evaluation of membrane-assisted esterifications compared with the conventional distillation technique, a decrease of 75% in energy input and 50% lower investment and operation costs can be calculated. The characteristics of the membrane and the module design mainly determine the investment costs of membrane processes, whereas the operational costs are influenced by the hfetime of the membranes. 

S.V. Satyanarayana and P.K. Bhattacharya, Pervaporation of hydrazine hydrate Separation characteristics of membranes with hydrophilic to hydrophobic behaviour, J. Membr. Sci., 238(1-2) 103-115, July 2004. 

Pervaporation has been successfully used both to reduce the alcohol content and to concentrate the congeners in bourbon whiskey (Table 6). The resulting products had taste, aroma, and color characteristics similar to the original bourbon but at a substantially higher intensity, reflecting the effect of the alcohol reduction and congener concentration. 

The permeation and separation characteristics of PVA-g-AN membranes toward acetic acid-water mixtures were expressed as permeation rate (flux) (0, separation factor (a) and pervaporation separation index (PSI). 

T. Uragami, T. Morikawa, Permeation and separation characteristics of alcohol-water mixtures through poly(dimethyl siloxane) membrane by pervaporation and evaporation, J. Appl. Polym. Sci. 44 (1992) 2009-2018. 

As an example of hybridization of zeolites with cellulose derivatives, self-supporting zeolite membranes with a sponge-like architecture and zeolite microtubes were prepared by using CA filter membranes as a template [154]. The hierarchical structure with sub-nanometer- to micrometer-sized pores is a characteristic of great promise for a wide range of applications such as catalysis, adsorption, and separation. There was also an attempt to prepare alginate membranes incorporated with zeolites, e.g., for pervaporation separation of water/acetic acid mixtures [155]. 

In certain cases it is desirable to selectively remove a volatile solute from a solution that contains other, less volatile, solutes as well as the solvent. Some examples are the reduction of ethanol content from alcoholic beverages or from dilute alcoholic extracts of aromatic flavors and fragrances from plant sources such as fruits or flowers. Conventional pervaporation would facilitate removal of water from such mixtures while retaining ethanol and the higher molecular weight organics that comprise the characteristic aroma and flavor profile of the products of interest. On the other hand, membrane distillation or osmotic distillation cannot retain the volatile components at all. 

Pervaporation membranes are of two general types. Hydrophilic membranes are used to remove water from organic solutions, often from azeotropes. Hydrophobic membranes are used to remove organic compounds from water. The important operating characteristics of hydrophobic and hydrophilic membranes differ. Hydrophobic membranes are usually used where the solvent concentration is about... 

Ideal pervaporation membrane should posses the following characteristics ... 

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