Posted November 23, 2009, at 12:43 p.m. CST

Florida-based Algenol Biofuels LLC and The Linde Group recently agreed to collaborate in a joint development project that will seek to indentify the optimum management of carbon dioxide and oxygen for Algenol's algae and photobioreactor technology.

Algenol has developed a photosynthetic algae technology in which proprietary algae cells essentially act as tiny ethanol factories. The algae consume carbon dioxide and sunlight, directly secreting ethanol. The algae utilized in Algenol's process are housed in large, sealed plastic photobioreactors. The algae culture is contained in the bottom third of the photobioreactor. The ethanol produced by the algae evaporates into the headspace of the containers, where it can be collected and purified.

The Linde Group is a global engineering company that has a wealth of experience in the cost-efficient supply of carbon dioxide for climate- and eco-friendly carbon dioxide recycling applications. The joint development project formed by the two companies will ultimately seek to develop cost-efficient technologies that can be used to capture, store, transport and supply carbon dioxide specifically for Algenol's ethanol production process.

According to Algenol CEO Paul Woods, the technology needed to capture and supply carbon dioxide to algae processes is markedly different than the technologies that are being developed to capture and store carbon dioxide for other purposes, such as enhanced oil recovery and sequestration. While capturing and processing carbon dioxide for sequestration requires high concentration and pressurization, the algae process requires much less concentration and pressurization. "We are talking about 100 or 200 psi (pounds per square inch) instead of 2,500 to 3,500 psi, and concentration under 30 percent as opposed to above 96 percent," he said. "These things make delivery of [carbon dioxide] to algae much cheaper."

Woods said the goal of the joint development partnership between Algenol and The Linde Group is to tailor carbon capture, storage and transportation technology specifically to the needs of Algenol's ethanol production technology. The two companies will also work together to explore technology that could be used to remove oxygen from Algenol's photobioreactors.

"All photosynthesis creates oxygen … in our case two to three molecules of oxygen for each molecule of ethanol," Woods said. "So, we're not talking about a little bit of oxygen, but a huge quantity of it." He said Algenol and The Linde Group will work to evaluate if it is most efficient to simply vent that oxygen back to the atmosphere, or if there is a value in capturing it for other purposes. According to Woods, one potential value in capturing the oxygen is that it could be supplied to a coal-powered facility. A supply of oxygen at a coal plant could be used for cleaner-burning coal and would result in the coal facility emitting a pure stream of carbon dioxide as a flue gas. The pure carbon dioxide stream could then be supplied back to the algae process, resulting a symbiotic relationship.

SOURCE: ETHANOL PRODUCER MAGAZINE