Overview

Pervaporation and vapour permeation are established processes that are used in various industrial applications to process organic solvents. In the pharmaceutical and specialty chemical industry, ethanol and propanol, THF and ACN are common solvents which can be dehydrated. Other applications include solvent recovery, biofuel product and aroma recovery. For several years, pervaporation membranes have been integrated into industrial processes, in combination with different unit operations. Energy saving can be up to 50-70% compared to standard applications, such as entrainer distillation or molecular sieving. The integration of pervaporation with existing processes debottlenecks plants and/or reduces energy.

A pervaporation process is one where the membrane is contacted with a liquid phase. However, a vapour permeation process is one where the membrane is contacted with a vapour phase (for example, where the feed comes from an evaporator or a rectification column). Pervaporation and vapour permeation can be applied to the dehydration of organic solvents or splitting azeotropes. Other applications include methanol removal from organic mixtures or the separation of valuable volatile components (eg aromas) from aqueous mixtures. Pervaporation and vapour permeation processes often lead to lower operating costs and a much more elegant and simpler process, even for existing plants.

Pervaporation and vapour permeation processes are not pressure driven membrane processes. Separation occurs due to the chemical affinity of the feed components for the membrane material itself, and secondly the difference in partial pressure between the feed and permeate side of the membrane. Membrane materials are typically polymer or ceramic.

In addition to alcohols like ethanol, propanol, other compounds like esters, ethers, ketones, and multi-component mixtures are also dehydrated using this technology.

Methanol also forms azeotropes with many organic substances. However, the miscibility of methanol with these organic compounds is better than with water and phase separation for simple methanol removal is rare. The application of methanol selective pervaporation membranes can simplify these processes as azeotropic streams can be simply separated, significantly reducing energy requirements.

Different membranes are available to serve a wide range of applications. Close co-operation with the customer, testing at small scale and operating experience overcomes the challenges of scale-up to find the optimum process and operating conditions.

This webinar will explain and summarise:

• What is pervaporation? (very briefly)
• Where is pervaporation used: dehydration and separating azeotropes
• Typical plant designs: pervaporation and vapour permeation
• Commercial membranes available
• How are the membranes used in industrial applications and what are the energy savings (industrial case studies showing simple flowsheets and energy savings)?
• How are membranes tested for industrial applications?
• Potential applications such as esterification, aroma recovery, desalination

This webinar is suitable for students or qualified engineers and scientists looking to gain knowledge in the field of membrane assisted distillation processes. A basic introduction to the technology will be presented along with a series of real industrial case studies. This will provide a strong platform to gain knowledge, understand what the technology can offer and where to go for further investigations/information.

Speaker

David Gladman FIChemE, DeltaMem AG (formerly part of Sulzer Chemtech)

David is based in Switzerland and works for DeltaMem AG (formerly part of Sulzer Chemtech), which is a company which specialises in the supply of pervaporation and vapour permeation membranes and plant. He is an experienced professional chemical engineer with broad process and engineering design, product and process development experience gained over 35 years. He has been responsible the design and implementation of chemical plant working in industrial gases, air pollution control and pervaporation. He has direct experience of the scale up, design, project management, installation and commissioning of pervaporation processes. 

The material presented has not been peer-reviewed. Any opinions are the presenter's own and do not necessarily represent those of IChemE or the Fluid Separations Special Interest Group. The information is given in good faith but without any liability on the part of IChemE.