Biodiesel producers are principally focused on one thing-producing quality biodiesel. So it's probably no surprise that the main coproduct of biodiesel production has gone under the radar-and perhaps simply underdeveloped-during the industry's emergence. Experts say glycerin, or glycerol as it's commonly called when unrefined, is only beginning to be looked at as a value-added opportunity, rather than a liability, for producers.

It's a history that isn't unheard of in the renewable fuels industry. Ethanol producers once virtually gave away their primary coproduct, a livestock and poultry feed called distillers grains. Now that coproduct, in its various forms, adds vital dollars to the bottom line of nearly every ethanol plant processing corn in the United States and Canada. Will biodiesel producers find an equally large market for glycerin?

The implications of biodiesel production on the nation's glycerin markets are huge. If just 2 percent of the nation's diesel fuel were switched to biodiesel, an additional 325,000 tons of crude glycerin would be produced annually. Glycerin production in the United States has been consistent over the last five years, averaging more than 350,000 tons per year.

Clearly, North American glycerin markets are going to be affected by industry growth. A 30 mmgy biodiesel plant will produce approximately 12,700 tons of 99.9 percent pure glycerin annually, according to Brian Duff, biochemical process engineer for Colorado-based BBI International.

The glut of glycerin on the market is not only a North American concern. Raffaelo Garofalo, secretary general of the European Biodiesel Board, alerted attendees at February's National Biodiesel Conference that excess glycerin on the European market is also becoming a point of concern. Likewise, fatty acid production from palm kernel oil and coconut oil in Southeast Asia is also adding to the world's glycerin supply, according to a source with a large multinational oleochemical company.

Those with a stake in the U.S. biodiesel industry, such as World Energy Alternatives President Gene Gebolys, are closely watching worldwide production levels. "We're well on the way to the biodiesel industry becoming the most important determinate in the supply of glycerin," Gebolys told Biodiesel Magazine. "We're already starting to see the indicators of that in Europe."

Purada Processing LLC, a World Energy wholly owned subsidiary, operates an 18 mmgy biodiesel plant in Lakeland, Fla. A 15 million-pounds-per-year glycerin refinery is co-located on-site.

Agricultural giant Cargill announced plans to build a 37.5 mmgy biodiesel plant adjacent to the company's existing soybean crush facility in Iowa Falls, Iowa. Plans also call for a 20 million-pounds-per-year USP-grade glycerin refinery.
Both Gebolys and Duff agree its' feasible to construct a glycerin refinery collocated to a biodiesel plant. However, if a glut of unrefined glycerin enters the market, prices will undoubtedly drop.

The good news, according to Duff, is that glycerin is an incredibly useful molecule. "If it became available much cheaper, people would look at it for new uses," he said.

Researchers discover new uses
Researchers are studying ways to find new uses for glycerin from biodiesel production. One idea often thrown around is converting glycerin to antifreeze. Galen Suppes, a chemical engineering professor at the University of Missouri (UM), said the first phase of a project has been completed, aimed at converting glycerin to propylene glycol through hydrogenation. The process turns one mole of glycerin and one mole of hydrogen into equal parts propylene glycol and water. Suppes said the project produced high yields of propylene glycol, and plans are underway to scale up the process later this year to allow for rapid commercialization.

Two UM graduate students and Columbia, Mo.-based Renewable Alternatives LLC are developing the project. The company provides technical service components for the commercialization of the technology, according to Suppes.

Researchers at Washington State University's Biological Systems Engineering Department are studying how to develop omega-3 fatty acids using glycerol. They are also studying the possibility of creating succinic acid and succinate salts from glycerol. Succinic acid is an important industrial chemical that is widely used in many applications. In fact, due to its potential, the U.S. DOE has identified succinic acid as one of the top 12 biorefinery chemicals that can be derived from biomass.

Glycerin typically doesn't burn well, limiting its use as a biodiesel plant energy source. However, Virent Energy Systems believes that glycerol can be an energy source through aqueous phase reforming (APR). The APR system generates hydrogen from aqueous solutions of oxygenated compounds, such as biomass-derived glycerin, in a single-step reactor process. Virent's technology is largely based upon the research of Jim Dumesic of the University of Wisconsin-Madison department of chemical and biological engineering. Virent targets biodiesel-produced glycerin because it is cheaper and readily converts to hydrogen, according to CEO Eric Apfelbach. He said that sodium hydroxide, methanol and the high pH levels common in low-grade crude glycerin actually help the process. "We found we can very effectively reform these crude mixtures," Apfelbach said.

Apfelbach said approximately 10 pounds of glycerin can be converted to 1.5 pounds of hydrogen in Virent's process. "We can generate gas from glycerol for less than $2 per kilogram because glycerol is so cheap," he said.

Duff said converting glycerin into hydrogen is possible, but the economics are sketchy. However, if natural gas prices continue rising, it may become more appealing.

Consistency, quality are key
Crude glycerin's consistency and quality are also becoming issues with growing worldwide biodiesel production. The various impurities make it difficult to use. Excess methanol can also create costly shipping situations.

Crown Iron Works, a Minneapolis-based process technology provider, produces biodiesel plants and glycerin refineries for the oleochemical industry. "Glycerin coming out of our biodiesel plant has to be relatively standard so a glycerin refiner doesn't have to get equipment specialized for the glycerin," said Derek Masterson, product sales manager.

Masterson said the crude glycerin from Crown Iron Works plants is typically 80 percent pure. He said the refineries are not designed to handle all the contaminants in the crude glycerin. "Some people ignore the glycerin end, and allow methanol and other things to go along for a ride," Masterson said. "It's difficult for a refiner to take care of."

Crude glycerin from the Asian fatty acid markets is generally more consistent than the North American crude supply. The most consistent North American crude glycerin is typically from biodiesel plants integrated in soy oil processors, according to the oleochemical company source.

Gebolys said even regarding today's market conditions that he would put in a glycerin refinery in today's biodiesel plant. "If you put in a refinery, you have two markets to play in-the refined market is different than the crude market," he said.

"We used to call glycerin a niche," Apfelbach said. "Then we looked at global supply and forecast and realized it's a big niche." n

Dave Nilles is associate editor of Biodiesel Magazine. Reach him by e-mail at dnilles@bbibiofuels.com or by phone at (701) 746-8385.