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How can DME alter the future of U.S. propane?

March 10, 2011 By    

As the propane industry ends an era and prepares for its centennial anniversary celebration in 2012, a new energy discussion is taking place and becoming harder to ignore – because the concept is already happening around the world.

While propane has relied successfully on its fundamental, versatile qualities for nearly 100 years, another molecular compound exists that could join with propane and drive it into the future.

The molecule is best known as DME, or dimethyl ether, which has established a foothold in other countries, particularly China. DME’s striking similarities to propane have some within the industries exploring what they can do for each other.

That’s where the discussion begins.

“It’s a lot easier to talk about these things than do it, but the good news about DME is that there are people actually doing it,” says Larry Osgood, president of Consulting Solutions LLC, who is working on DME’s prospects for the propane industry.

DME can be described as “synthetic propane.” It is the simplest ether, with physical properties that are consistent with propane. It is a clean, colorless gas that is easy to liquefy and transport. It also contains cost benefits, as it doesn’t follow the up-and-down nature of crude prices. DME is used extensively as an aerosol propellant – manufactured in the United States by DuPont – as well as an LP gas substitute around the world.

The blending process
According to the International DME Association (IDA), more than 70 percent of the DME produced globally is blended with LP gas. China produces most of the world’s DME, at more than 2 billion gallons last year. The country blends about 20 percent DME with the LP gas that it imports, using the fuel residentially for heating, cooking and other applications. In these 80/20 blending ratios, generally no modifications to equipment or distribution networks are required.

“DME is handled almost exactly as you would handle propane,” says André Boehman, professor of fuel science and materials science and engineering at Penn State University, and an IDA member. “DME looks and acts much like LPG.”

DME is produced from multiple sources, including coal, natural gas and biomass. But the latter source – renewable material – is driving the propane industry’s pursuit of DME and the new opportunities it could provide. DME can come from forest products, agricultural byproducts, dedicated fuel crops and waste from paper and pulp mills.

While DME could one day help to grow the U.S. propane supply, those working behind the scenes now are emphasizing its renewable component. This would create a bio-DME classification and, thus, “green” propane.

“We’re viewed as a niche fossil fuel, so unless we position propane as a future fuel, no one else is going to do it for us,” Osgood explains. “We’re doing a much better job in Washington, but the policymakers at DOE and EPA don’t hear from us, and they’re the ones spending the money to determine where we’re going to go. DME puts us into the last piece of being renewable. How do we show we’re in the game? To position propane as a renewable fuel and a future, sustainable fuel.”

Osgood penned a letter to some propane industry members, detailing a continued difficulty in propane’s positioning among notable motor fuels, particularly ethanol. But he believes DME can reposition propane from the basement of future fuels discussions to the top shelf with ethanol, and above biogasoline and biodiesel.

Interest in DME blending as a domestic transportation fuel is growing. Osgood is a member of the North American DME Vehicle Demonstration Coalition. Its goal is to create market demand for DME as a renewable transportation fuel in North America through vehicle demonstration programs in New York, California and Canada.

According to a coalition slide presentation, alternative fuel equipment provider CleanFUEL USA recognizes DME “as the future of propane” and is offering support for a propane/DME blended vehicle demonstration program.

“We’re the only fuel today that’s left out of the ‘bio’ future discussions,” Osgood says. “We just don’t have a role in that yet, and DME is a way for us to have that same participation in vehicles and other applications that everybody else is enjoying today.”

Strong voices
IDA, which has a joint agreement with the World LP Gas Association, has served as the global voice of the DME industry since 2001 and works to promote the use of DME worldwide. A North American DME Development Committee has been established, as a branch of IDA, to help move DME into the mainstream of U.S. and Canadian fuels. The North American group’s goal is to have DME classified under EPA’s Renewable Fuels Standard so it could reap governmental benefits, such as tax incentives.

“DME uniquely provides the potential for large-scale renewable content to be brought into the propane infrastructure, and that raises the question of what can we do to grow the market for propane-type fuels?” Boehman says. “Can we get propane-type fuels into the transportation sector [in a bigger way]? Can DME help to displace other forms of fuel that are used in residential applications?”

DME officials have met with the National Propane Gas Association (NPGA) and the Propane Education & Research Council (PERC) over the past year or so, and the topic has come up in various committee meetings. In fact, Boehman presented a DME overview to NPGA’s Technology Standards & Safety Committee last September. He received questions on DME’s energy content, system compatibilities and mixing processes.

Boehman, who has studied DME for about 15 years, submitted proposals on DME to PERC last year. His fascination for DME is largely as a motor fuel – he helped to convert a shuttle bus at Penn State to run in part on DME. Neither PERC nor NPGA has taken any formal action on the topic, however.

Future impacts
Greg Kerr, director of research and development for PERC, says the council does not yet have an official view on DME. PERC did contract with Gas Technology Institute (GTI) to analyze the concept of synthetic or bio-LPG. In its 2009 report, GTI says that PERC could play a leadership role in educating the industry about the commercial potentials of synthetic or bio-LPG/DME.

“It’s too early to tell,” says Bruce Swiecicki, senior technical adviser for NPGA, on DME’s prospects for the propane industry. “I’m not sure of the impact it will have on the propane industry. I haven’t seen enough to persuade me one way or the other, that it’s good or bad. But it’s certainly worth exploring.”

The International American Society for Testing and Materials (ASTM), a standards development organization, might think so. Swiecicki, a member of the ASTM subcommittee that writes specifications for LP gases, introduced the idea of creating a specification for DME. The subcommittee “was interested in it,” but requested more information, he says.

Osgood marvels when considering the possibilities for DME. Straight DME could replace diesel fuel and be used in diesel engines, he says. Propane retailers could run their bobtails on DME, and the industry could one day distribute DME as a “green” or bio-propane.

In the meantime, the North American DME Development Committee will continue to seek support for DME, address regulatory issues and consider demonstration projects and additional research to help establish DME as an up-and-coming fuel that just might al
ter the future of propane.


About the Author:

Brian Richesson is the editor in chief of LP Gas Magazine. Contact him at or 216-706-3748.

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