Creating Sustainable Energy from Microalgae




December 4, 2012

Stevens researchers to produce diesel fuel from microalgae in a cost-competitive, high-performance CO2-neutral process.

Chances are that you have eaten corn today in some form. Corn is one of the largest crops produced in the United States, and it is used in many of the foods that almost everyone consumes every day. As an important biofuel source, corn is also used to produce significant amounts of ethanol for blending with gasoline. With the growing need for sustainable energy sources, about 40% of the U.S. corn crop is reserved to be converted to biofuel. Factors including increasing demand for food and the recent widespread drought have caused the price of corn to skyrocket, consequently raising the cost of food and fuel significantly. The price for corn is so high, that some farmers are supplementing their corn feed with chocolate.

In the search for new and alternative sources of fuel that are sustainable, economical, and do not affect food production, a research team led by Dr. Adeniyi Lawal of Stevens Institute of Technology is investigating microalgae as a non-food biomass fuel source. Dr. Simon Podkolzin, also of Stevens, serves as a Co-PI on the team. Funded by a $650,000 grant by the U.S. Department of Energy Office of Biomass Program, the team is developing a transformative technology that converts the renewable and abundant supply of algae into cost-competitive, high-performance biofuels.

“With the United States alone consuming approximately 140 billion gallons of gasoline per year, it is clear a non-food biofuel feedstock must be developed to relieve the strain on food production,” says Dr. Michael Bruno, Dean of the Charles V. Schaefer, Jr. School of Engineering and Science. “With global implications such as reduced reliance on foreign oil and efficient methods of green fuel production, Dr. Lawal’s research is critical.”

Microalgae are single-cell photosynthetic organisms known for their rapid growth, with some strains capable of doubling their mass several times per day. They are found in fresh and saltwater bodies and are promising candidates for an efficient and green source of biofuel. In some strains, more than half of the organism’s mass consists of energy-rich lipids or triglycerides, which are bio-oils that can be used to produce various advanced biofuels. These strains have the potential to produce 100 times more oil per acre than any other oil-producing crop. Furthermore, algae can be cultivated in large open ponds or in closed photobioreactors located on non-arable land in a variety of climates, even in unforgiving environments such as deserts. Biofuels could therefore be produced in areas that are not agriculturally viable, avoiding interference with any sort of food production. Although the technology shows tremendous promise, researchers have struggled to establish an efficient and cost-effective process for the microalgal biofuel production.

In response to this obstacle, the research team has proposed a new commercially viable process to convert microalgae into diesel in three steps. First, algal oil is extracted from microalgae. The oil is then purified of metals and metalloids to produce cleaner, pre-refined algal oil. Without this unique pre-refining approach, the high level of contaminants in crude algal oil would rapidly deactivate the catalysts that facilitate essential reactions in the process, making it impossible to convert to green diesel. The final step is a process called hydrodeoxygenation, in which hydrogen is added to the purified algal oil to remove oxygen , creating green diesel with the clean byproduct of water (H2O). “The entire process is CO2-neutral, making microalgae-based diesel more environmentally friendly than fossil fuel based-diesel,” says Dr. Lawal. “Carbon dioxide from the atmosphere is taken in via photosynthesis in microalgae, and returned to the atmosphere when the final diesel product is converted into CO2 through combustion.”

In addition to Stevens faculty, the research team comprises two industrial partners, and two consultants. The principal industrial partner is SRS Energy (now Valicor Renewables, LLC), which will perform the extraction and purification steps of the process. The second industrial partner is BASF Catalysts LLC, which supplies the catalysts integral to the work at Stevens for the challenging final step of hydrodeoxygenation. Dr. Brian Goodall, Vice President of Business Development at SRS Energy, and Dr. Robert Farrauto, former Vice President of Hydrogen and Fuel Cell Technology at BASF Catalysts LLC, are co-principal investigators in the project. Dr. James Manganaro and Dr. Dongying Qian serve as consultants.

A preliminary economic analysis shows that using microalgae as a biofuel source at a large-scale is cheaper than petroleum-derived diesel. At just 35,000 barrels per day of diesel from microalgae, the production cost is approximately $2.80 per gallon, which is competitive with petroleum-based diesel. According to the proposed study, at larger quantities the cost would be even lower.

Dr. Lawal brings a wealth of knowledge and research innovation to the field having led two major projects on thermochemical conversion of biomass waste to transportation fuel; a DOE-Office of Biomass Program-sponsored project on the distributed production of advanced biofuels from biomass waste, and an Office of Secretary of Defense, DoD program on biomass waste conversion to liquid fuels for national security.

“This important and transformative research encompasses food and energy sustainability,” says Dr. Henry Du, Department Director of the Chemical Engineering and Materials Science Department. “We have only begun to tap the enormous biofuel potential of microalgae.”

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