Thar Process receives grant for distillation replacement technology

By Ron Kotrba | March 05, 2009
The state of Pennsylvania is funding 49 biofuels and clean energy projects through two separate programs: the Energy Harvest Grant program and the Alternative Fuels Incentive Grant program, worth a total of $13.7 billion. One particular grant recipient plans on making improvements to the conventional ethanol production model currently in widespread use throughout the industry.

Thar Process Inc. received a grant award for $588,000 under the AFIG program to build a pilot-scale plant to demonstrate technology that uses pressurized propane to remove the high volumes of water from the beer coming out of the fermentation process without using conventional distillation or drying methods. "It's a liquid-liquid extraction process that could be a drop-in replacement for an existing ethanol plant's conventional distillation," said John Davis, development manager for Thar Process. "I want to emphasize this: With what we're working on, you can take an existing ethanol plant, rip out its existing distillation system and put this one in."

How much water could the extraction system remove? "It depends on how you do it," Davis said. "We don't want to talk too much about that, but [the system] can take [the alcohol] to a full anhydrous state, so you're not only eliminating the distillation step, but you can eliminate the molecular sieve drying phase, too."

Davis said Thar Process has a lot of experience in high-pressure extraction, primarily involving supercritical carbon dioxide, supercritical water and propane. "It's our basic business," he told EPM. "It's been applied commercially, mainly to extractions from herbal sources—plants and spices, that sort of thing." He also said the pressurized propane extraction technique could be an alternative approach to hexane extraction for the chemical removal of vegetable oils from oilseeds. "In a separate project (sponsored by the National Institute of Technology), we're pursuing an application of this for biodiesel processing," he said. "It involves the supercritical carbon dioxide extraction of soybean oil from
soybeans. That's been going on for a year now, so we're one year into that two-year project."

Davis said the equipment required to convert the water-laden beer into ethanol using high-pressure propane extraction would include a "couple of extractor columns and a depressor—that's basically it." The propane used in the extraction process is recycled, according to Davis, and the energy savings from bypassing the conventional distillation and molecular sieve drying steps is significant. "Our initial studies on this indicated to us that we would be cutting energy consumption by about one-half," he told EPM.

The Pennsylvania grant will be used to build a pilot-scale demonstration facility in Pittsburgh, where Thar Process is headquartered. "It's a two-year project, and we just got the OK for this, so we'll be launching it [by the end of April]," Davis said. Applying this technology to ethanol has been "discussed in laboratories for a few years," he said, but has never been demonstrated. He wouldn't reveal the production capacity of the pilot plant, but he said the company aims to scale up to a 25 MMgy facility in the future.