GREEN, CLEAN EMISSIONS CONTROL

In Business, Jul/Aug 2005 by Greer, Diane

"As long as the economic discussion is framed as 'industry vs. environment,' there is very little room for new thinking," says the founder of GreenFuel Technologies Corp. "But when we show people that our system is a tool to profit by reducing waste, the wheels really start turning."

FROM A DISTANCE, the structure atop the power plant roof at the Massachusetts Institute of Technology (MIT) in Cambridge appears to be a piece of avant-garde art. Thirty, eight-foot tall triangles made of clear plastic tubing sit side by side, circulating a bubbling green liquid. Closer inspection reveals the tubes to be filled with water and the fastest growing plant on earth - algae.

This innovative mechanism, the brainchild of Dr. Isaac Berzin - the founder of GreenFuel Technologies Corporation - harnesses the algae's photosynthetic process to consume waste gases from the power plant, fueling the algae's growth and delivering cost-effective emissions control. Once a day, the algae is harvested and dried, generating a commercially valuable by-product, known as algae biomass, used to create products ranging from biofuels to animal feed. "Our system is essentially a tool that enables the industry to profit by reducing waste," explains Berzin.

FUELING PHOTOSYNTHESIS WITH FLUE GASES

A single celled organism, algae, lies at the heart of the GreenFuel Technologies effort. During photosynthesis, algae utilize solar energy to consume carbon compounds, such as carbon dioxide (CO2). Berzin is leveraging this process to turn CO2, a greenhouse gas found in flue gases, into oxygen and food to fuel the algae's reproduction. Algae also break down another flue gas component, nitrogen oxides (NOx) - a precursor to smog - into nitrogen and oxygen. Nitrogen serves as a nutrient, promoting algae growth.

Algae are ideal for Berzin's application. The organisms reproduce rapidly, doubling in volume in a matter of hours. Algae thrive in extreme conditions, able to withstand high temperatures and live in water sources readily available near power plants, even untreated or brackish water. Algae biomass can be used to produce biodiesel, bioethanol and animal feed or burned to generate energy.

Exploiting algae to reduce waste gas emissions from power plants is not a new concept. From 1978 to 1996, the U.S. Department of Energy (DOE) Aquatic Species Program researched the production of biodiesel from algae. As part of the study, algae grown in large-scale ponds in Roswell, New Mexico, were fed exhaust gas from coal-fired power plants. By carefully controlling pH and physical conditions, researchers achieved a 90 percent utilization of the injected CO2 and high algae yields.

Unfortunately, cultivating large volumes of algae in open pond systems proved to be impractical and expensive. Algae production was adversely affected by the uneven distribution of sunlight throughout the pond, wind blown contaminants and fluctuating temperatures. Harvesting the algae was difficult and expensive. Biodiesel generated from the ponds was calculated to cost twice as much as petroleum-based diesel fuel.

INNOVATIVE DESIGN

"We are beneficiaries of research done by DOE and others in the area," says Julianne Zimmerman, Director of Business Development at GreenFuel Technologies. "Isaac Berzin read about this work and came up with ways to improve efficiency and take an alternative approach to this technology. The result is the very simple and elegant triangular enclosed bioreactor."

Polycarbonate plastic tubes fabricated into a right triangle form the backbone of GreenFuel's bioreactor. The vertical leg of the triangle stands eight feet tall with a horizontal leg extending six feet. Placement of the device, with the hypotenuse facing the sun, optimizes sunlight penetrating the system.

Flue gases pumped into the legs of the triangle circulate through the system once before being expelled through the top of the device. Since algae require solar energy to consume CO2, removal of it by the bioreactor depends upon the systems' exposure to sunlight. Removal of NOx is not dependent upon sunlight and occurs continuously.

Fluid and gas dynamics along with gravity control the circulation of algae and water within the device. Designing the system with different diameter legs and adjusting the volume of gases going into the bottom vertices creates a pressure gradient within the device. Changes in the local pressure gradient drive fluid flow through the bioreactor. "This configuration allows us to control the rate of rotation of the liquid in the bioreactor," says Zimmerman. "Control of the flow is simple and efficient."

OPTIMIZING ALGAE GROWTH

Sophisticated algae culture management and control systems constitute the other key components of the GreenFuel system. In 2001, when Berzin was a research fellow at MIT, he advised Payload Systems on the design of a research apparatus for NASA's International Space Station. "The apparatus was required to grow essentially any type of cell in anything between zero and earth gravity, with as little mass, volume and power as possible," says Zimmerman who also worked on the project for Payload Systems.