Patented Bio-PDO for Heat Transfer: CSP Meets Green Chemistry

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DuPont Tate & Lyle BioProducts (DPTL) is a joint venture between DuPont and Tate & Lyle which provides natural and renewably sourced industrial materials. In collaboration with Climalife, DPTL has developed and launched a new line of heat transfer fluids (HTF) under the brand name Greenway.

The Greenway fluids are marketed for use in solar thermal (AKA concentrating solar power) applications. The key ingredient in the heat transfer fluids is DPTL’s Susterra brand propanediol, a bio-based glycol.

DPTL owns several patents and pending applications relating to its bio-derived propanediol (Bio-PDO), including U.S. Patent No. 7,988,883 (’883 Patent), specifically directed to use of Bio-PDO in heat transfer compositions.

Entitled “Heat transfer compositions comprising renewably-based biodegradable 1,3-propanediol,” the ’883 Patent is directed to heat transfer or antifreeze compositions comprising biologically-derived 1,3-propanediol having a bio-based carbon content of at least 1%.

The independent claims of the ’883 Patent include a recitation that the composition “has a lower anthropogenic CO2 emission profile” compared to 1,3 propanediol with no bio-based carbon. The Bio-PDO can be generated by genetically-engineered E.coli bacteria or other microorganisms.

The patent makes the argument that its bio-based process is carbon neutral. According to the ’883 Patent, the compositions have less environmental impact because they take their carbon from plant feedstocks and release the carbon into the atmosphere to be used by plants again:

The biologically derived 1,3-propanediol (Bio-PDO) for use in the current invention, produced by the process described herein, contains carbon from the atmosphere incorporated by plants, which compose the feedstock for the production of Bio-PDO. In this way, the Bio-PDO used in the compositions of the invention contains only renewable carbon, and not fossil fuel based, or petroleum based carbon. Therefore the compositions of the invention have less impact on the environment as the propanediol used in the compositions does not deplete diminishing fossil fuels and, upon degradation releases carbon back to the atmosphere for use by plants once again. Thus, the present invention can be characterized as more natural and having less environmental impact than similar compositions comprising petroleum based glycols.

Like some of the patent litigation involving solar ovens and solar mounting systems, the Greenway HTF product containing patented propanediol is another example of green IP extending into downstream solar and penetrating the niche market opportunities offered by the clean tech industry.

Eric Lane is a patent attorney at McKenna Long & Aldridge LLP in San Diego and the author of Green Patent Blog. Mr. Lane can be reached at elane@mckennalong.com

About Author

Walter’s contributions to CleanTechies over the past 4 years have been instrumental in growing the publications social media channels via his ongoing editorial and data driven strategies. He is the founder and managing director of Sunflower Tax, a renewable energy tax and finance consultancy based in San Diego, California. Active in the San Diego clean technology community, participating in events sponsored by CleanTech San Diego, EcoTopics, and Cleantech Open San Diego, Walter has also been a presenter at numerous California Center for Sustainability (CCSE) programs. He currently serves as an adjunct professor at the University of San Diego School of Law where he teaches a course on energy taxation and policy.

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