The Opportunity with Permylene

Permylene membrane technology is poised to initiate a technological leap as a viable alternative to traditional high cost, energy intensive processes for olefin/paraffin separation. Permylene has recently been receiving significant interest from the refining and petrochemical industry in exploring a wide range of potential applications.

Refinery Olefins, especially ethylene and propylene, are the building blocks of many important plastics, polymers and other chemicals. As the world population grows and economies develop, the demand for olefin-based materials will continue to grow.

Major oil and petrochemical companies around the world are investing in technology to increase olefins production capacity. These investment decisions are being supported and justified by many factors including:

Lower cost feedstock from shale gas
Ever rising demand for plastics and other materials from growing and emerging economies
The opportunity for resource-based economies to add value through vertical integration, such as in the Middle East
Many existing facilities slated for expansion and retrofit to increase output and improve operational efficiency

Olefin/paraffin separation has traditionally been accomplished through the process of distillation. However, distillation has significant economic drawbacks, including:

Substantial capital costs, thereby eroding project returns
Extreme energy consumption leading to high operating costs
Some olefin separations, especially butene separations are currently impractical using conventional distillation technology but would be commercially desirable if they could be economically achieved
The inability or infeasibility of recovering unreacted olefins from purge or vent streams destined for flaring and subsequent undesirable environmental emissions

For over 30 years companies in the petrochemical industry have sought commercially viable alternative separation technologies to distillation. Many attempts have been made to satisfy this need by industry R&D teams, academic researchers, government researchers and by technology providers looking to commercialize a new, more economical, environmentally advantaged technology.

Imtex is the first company to have successfully answered this need and has created the first commercially viable alternative to distillation for olefin/paraffin separation with its Permylene membrane technology. Permylene membrane technology meets industry's need for a stable, high performance olefin paraffin separation process that is designed to withstand the rigors of long-term operation.

See our news article Permyene: ON the Cuttinng Edge of World Change?

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Technology

Permylene Overview

Imtex's Permylene membrane separation technology revolutionizes olefin extraction and purification for the petrochemical and refining industries. Imtex membrane technology is currently the only commercially viable, high-performance alternative to traditional distillation techniques for olefin-paraffin separation and purification. The technology is also able to perform separations that have, to date, been considered difficult or impractical.

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Permylene Process

Imtex’s Permylene process focuses on the purification of olefins (ethylene, propylene and butenes) by separating them from their corresponding paraffins (ethane, propane, and butanes respectively). Olefins are the predominant building blocks in the production of many polymers, plastics and other products. The incumbent olefin separation technology, fractional distillation, is expensive, energy consuming and polluting with high levels of greenhouse gas emissions. Depending upon the type of facility, the Permylene process would reduce capital expenditure by 30 - 75% and operating costs by 30 - 90% through improved energy efficiency, as no energy is required to boil or condense the process streams for separation. As a result, greenhouse gas emissions are also reduced by up to 90%.

Permylene offers substantial economic and environmental benefits over the distillation processes typically employed for olefin/paraffin separations, with many wide-ranging applications.

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Olefin Paraffin Separation

Permylene uses membranes made from chitosan for its separation process. Chitosan is a natural source polymer derived from chitin, the major structural constituent of the exoskeleton of crustaceans and insects. The membranes are designed for industrial conditions, and installed in an industry standard spiral wound membrane element format.

In a petrochemical plant, an olefin-paraffin feed mixture is fed into the membrane element which separates the gases. The process is modular and highly scalable, allowing for the installation of any number of membrane elements depending on the plant production capacity.

The robust Permylene membrane technology results in high separation performance that delivers polymer-grade olefins. The composition of the Permylene membrane allows ethylene, propylene and other olefins to chemically interact with it, facilitating olefin transport across it while rejecting paraffins and other constituents.

Imtex Membrane Module

Steady and stable olefin transport is achieved in continuous, non-stop operation via circulation of an aqueous silver nitrate solution over a spiral wound membrane containing a hydrogel coating.

The silver ions in the silver nitrate solution within the hydrogel structure form a reversible complex with the double bonds of the olefin molecules
Any molecules not possessing a double bond are rejected, resulting in excellent selectivity
The process is primarily driven by the olefin partial pressure differential across the Permylene membrane resulting in commercially attractive permeation rates

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Permylene Performance

Permylene membrane systems have several highly desirable olefin-paraffin separation performance attributes:

Typical olefin product purities are > 99.5% for a wide variety of olefin-paraffin feed compositions and high recovery levels are achieved
Commercially attractive permeation rates are achievable and olefin recovery often exceeds 90%
Stable performance has been demonstrated over tests covering thousands of hours

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