TECHNOLOGIES

PERVAPORATION (PV) & VAPOR PERMEATION (VP)

Pervaporation (PV) and Vapor permeation (VP) are membrane separation techniques which are used to separate or recover components from liquid or vapor mixtures respectively by selective permeation.

Some of the industrial separation problems that can be solved with the use of PV and/or VP are listed below.

Conventional Technologies & Their Limitations

Simple Distillation:

Solvent-water mixtures can be easily separated based on relative volatility.
Simple Batch / Continuous operation can be done.
Azeotropic mixtures cannot be separated using simple distillation.

Azeotrope / Extractive Distillation:

Azeotrope or extraction solvent is to be recovered
GC purity of solvent is reduced

Pressure Swing Distillation:

Possibility of Solvent Degradation
High utility consumption

Liquid-Liquid Extraction (LLE):

Extraction Solvent has to be recovered
GC purity of solvent is reduced
Limited applicability

Adsorption / PSA / TSA:

Media has to be regenerated
Purge /drain steam is to be treated
Not suitable for feed with water content more than 1% (for TSA) and more than 5% (for PSA).
Remains of unidentified trace impurities or trace impurities due to molecular dehydration
Fine particles due to attrition

Crystallization :

Depends on the Solid-Liquid Equilibrium.
Problems with slurries and crystals.
Limited applicability

Salting Out :

SLLE based separations
Salt has to be recovered or high TDS, high COD effluent is to be treated
Solvent has to be recovered from salt phase
Possibility of Side Reactions
Not suitable for drying to less than 1-2% water
Messy and corrosive effluent to be handled

ZeoSep® Technology

ZeoSep® SolvDry Membrane and Module

• Zeolite Membrane Film hydrothermally grown on Microporous Ceramic Support

• Hydrophilic Membrane with Pore size ~ 0.4 nm

• Adsorption – Diffusion separation mechanism

Key Features: -

High Flux & Super High Selectivity for Water Permeation
High Chemical, Mechanical and Thermal Stability

A Multi-pass ZeoSep SolvDry Tubular Membrane Module is shown below. This module has Efficient Mass transfer and Easy Maintenance.

ZeoSep Pervaporation (PV)

The schematic process flow diagram has been shown for ZeoSep SolvDry Pervaporation (PV) Membrane System. The Solvent-Water liquid Feed mixture is sent to the PV Membrane Module to separate out water as the Permeate and Dry Solvent as the Retentate.

Governing Equation:

ZeoSep Vapor Permeation (VP)

The schematic process flow diagram has been shown for ZeoSep SolvDry Vapor Permeation (VP) Membrane System. The Solvent-Water mixture Feed is vaporized and sent to the Membrane Module to separate out water as the Permeate and Dry Solvent as the Retentate.

PolyGSep Technology

Solution – Diffusion Mechanism based Polymeric

These membranes are available as : –
Membrane Hollow Fiber
High Flux & High Selectivity

PolyGSep SolvDry Hollow Fiber Membrane Module

Key Features: –

Compact
Efficient Mass transfer
Condensable & Non-Condensable Sweeps to improve the Mass Transfer

PolyGSep Vapor Permeation (VP)

The schematic process flow diagram has been shown for PolyGSep SolvDry Vapor Permeation (VP) Membrane System. The Solvent-Water mixture Feed is vaporized and sent to the Membrane Module to separate out water as the Permeate and Dry Solvent as the Retentate. In case Methanol is present in the mixture which has to be separated, it can be done using PolyGSep membranes to permeate Methanol out along with water.

Vapor Permeation (VP) vs Pervaporation (PV)

The fitment of the mode of operation is checked on case-by-case basis. The high-level comparison is given in table below:

ZeoSep / PolyGSep Applications

Green field application- Solvent drying of solvent rich streams Example- A Vapor Permeation system for solvent dehydration

Debottlenecking of distillation columns & adsorption systems
Example- Second distillation column replaced by membrane module to increase system capacity with existing hardware.

Membrane reactors for in-situ removal of water/methanol in condensation reactions
Example- A Membrane reactor system to enhance condensation reactions.

PolyGSep vs ZeoSep

Additional Points:

Suspended solids and Dissolved solids cannot be fed directly to the membrane. They may be processed in VP system and collected as non-volatile purge, subject to limitations. Else, they need to be removed.
Water Tolerance is High which can further be improved by integrated distillation operation.
Solvent Recovery is generally high but need to be judged on case basis. Moreover, recovery can be improved in distillation hybrid systems.

Solvent Compatibility For Drying Of Organic Solvents

Both PolyGSep & ZeoSep

Alcohols

Ethanol
n-Propanol
Isopropanol
tert-Butanol
sec-Butanol
Allyl Alcohol

Ketones

Acetone
Methyl Ethyl Ketone (MEK)

Ethers

MTBE
Tetrahydrofuran (THF)
Diisopropyl Ether (DIPE)
1,4-Dioxane-

Esters

Methyl Acetate
Ethyl Acetate
N-Propyl Acetate
Iso Propyl Acetate

With ZeoSep Only

Carboxylic Acids

Formic Acid
Acetic Acid

Nitriles

Acetonitrile
Propionitrile
Acrylonitrile

Amines

Tri Ethyl Amine
Pyridine

Chloro alkanes

Dichloromethane

Aldehydes

Propanal
Butanal

Sulfoxides

Dimethyl sulfoxide

Amides

Dimethyl formamide
Dimethyl acetamide

Alcohols

Methanol

Pyrrolidones

N-Methyl-2-Pyrrolidone

Notes:

1. Solvents mentioned above are mere examples within different functional groups. There are many other solvents that can be processed. For any other solvents please contact us.
2. Multicomponent mixture of above solvents can also be processed, as applicable.

CONVENTIONAL & HYBRID TECHNOLOGIES OFFERED

Conventional

Equilibrium Base
Distillation (Vacuum, Atmospheric, Super-Atmospheric)-Simple, Pressure Swing, Extractive

Liquid – Liquid Extraction
Solution Crystallization
Stripping
Absorption (Scrubbing)

Adsorption & Ion Exchange Based

Temperature Swing Adsorption (TSA) [Regenerative and Non-regenerative]
Ion-exchange

Hybrid

Membrane Based Hybrid Processes

Membrane – Distillation Hybrids
Membrane-Adsorbent Hybrids
Other Hybrids

KEY PROCESS FEATURES

OTHER MEMBRANE SEPARATION PROCESS MODES

We also use following membrane processes whenever there is a compelling case for applying them. Except Gas Permeation, membranes used for these processes are third party membranes. However, process development, design and execution is done in-house.