Search results for "Pervaporation"

Production of Aldehydes by Oxidation in Aqueous Medium with Selective Recovery of the Product by Means of Pervaporation

2010

Prediction of mass fluxes in the pervaporation process of the ethanol dehydration, based on the free volume theory

2014

Metodę obliczania współczynników dyfuzji Maxwella-Stefana opartą na współczynnikach dyfuzji własnej przewidywanych wg zależności wynikających z teorii wolnych objętości, zastosowano do obliczania strumieni masy w procesie perwaporacyjnego odwadniania etanolu na membranie z alkoholu poliwinylowego PVA. Parametry metody wolnych objętości dla badanego układu wyznaczono oraz obliczono stężenia równowagowe w PVA stosując zmodyfikowaną metodę UNIFAC-FV a następnie obliczono udziały masowe w permeacie oraz współczynniki wzbogacenia. Obliczenia przeprowadzono dla danych eksperymentalnych opublikowanych w pracy [3]. Wyniki obliczeń porównano z wynikami uzyskanymi na instalacji doświadczalnej.

Process intensification in a photocatalytic membrane reactor: Analysis of the techniques to integrate reaction and separation

2017

Abstract Different methods to integrate reaction and separation in a membrane reactor are studied in the present work, with the aim being to highlight the pros and cons of the different alternatives and the effects of the intervening parameters. The coupling of the two processes can take place inside a single apparatus or using separate units. If a single apparatus is utilized, the coupling is more direct, but separate units offer higher degrees of freedom for the design with more opportunities to optimize the system without constraints. However, when using separate units, the integration of the two unit operations depends largely on the parameters intervening in the coupling procedure. The…

Extraction of benzaldehyde from fermentation broth by pervaporation

1996

Abstract The application of pervaporation to extract benzaldehyde produced by microorganisms is considered. A model system was used to study the influence of different parameters and attempts to understand better the mass transfer of this flavour compound. Benzaldehyde was removed from a culture medium from which it was produced by Bjerkandera adusta . The performance of these processes is compared.

Predicting mass fluxes in the pervaporation process using Maxwell-Stefan diffusion coefficients

2018

Abstract In the past decades, it has been proven that pervaporation is an effective and energy-efficient membrane process for the separation of liquids that are difficult to separate in classical processes. The demand for new process applications has increased the need for mass transfer simulation methods, considering the interactions between the system components and the influence of process parameters on the permeation fluxes and at the same time requiring as few experiments as possible. The aim of the study was to find out whether the calculation of mass fluxes of multicomponent fluids based on the system of generalized Maxwell-Stefan equations (GMSE), using Maxwell-Stefan (M-S) diffusio…

EXTRACTION OF AROMA COMPOUNDS BY PERVAPORATION

1996

Removal of Intermediate Compounds in a Photocatalytic Process

2010

6th European Meeting on Solar Chemistry and Photocatalysis: Environmental Applications (SPEA6) -- JUN 13-16, 2010 -- Prague, CZECH REPUBLIC

Heterogeneous Photocatalysis and Photoelectrocatalysis: From Unselective Abatement of Noxious Species to Selective Production of High-Value Chemicals

2015

Heterogeneous photocatalysis and photoelectrocatalysis have been considered as oxidation technologies to abate unselectively noxious species. This article focuses instead on the utilization of these methods for selective syntheses of organic molecules. Some promising reactions have been reported in the presence of various TiO2 samples and the important role played by the amorphous phase has been discussed. The low solubility of most of the organic compounds in water limits the utilization of photocatalysis. Dimethyl carbonate has been proposed as an alternative green organic solvent. The recovery of the products by coupling photocatalysis with pervaporation membrane technology seems to be a…

Photocatalytic process intensification by coupling with pervaporation

2011

The integration of photocatalysis with a membrane separation process, in particular pervaporation, permits the recovery of valuable intermediate compounds (aromatic aldehydes) while they are produced avoiding their further degradation in the reactive ambient. In this way the yield and the conversion are enhanced. The coupling of the two processes is straightforward and the integration is complete even maintaining pervaporation and photocatalysis in two separate apparatuses provided that the process stream is continuously recycled at a sufficiently high flow rate. Additional advantages are: higher degree of purification of the aldehyde in the powder-free product stream, semicontinuous produc…

Green Synthesis of Vanillin: Pervaporation and Dialysis for Process Intensification in a Membrane Reactor.

2019

In the present work, two different membrane processes (pervaporation and dialysis) are compared in view of their utilization in a membrane reactor, where vanillin, which is probably the most important aroma of the food industry, is synthesized in a green and sustainable way. The utilized precursor (ferulic acid, which is possibly a natural product from agricultural wastes) is partially oxidized (photocatalytically or biologically) and the product is continuously recovered from the reacting solution by the membrane process to avoid its degradation. It is observed that pervaporation is much more selective towards vanillin than dialysis, but the permeate flux of dialysis is much higher. Furthe…