Non-Fouling Polymeric Membrane for Algae Dewatering

Currently there is great interest in the development of renewable fuels, such as biodiesel. Algae is one source of oil feedstock for biodiesel production that has been extensively investigated in recent years. Unlike vegetable oil crops, such as soybeans, algae grows very fast, can be grown on land of limited agricultural value, and can be grown in seawater or wastewater which are not suitable for agricultural crops. Despite the many advantages algae offers over more conventional oil feedstock crops, algae sourced biodiesel has not developed into a commercial process due to its high operating costs. One of the steps in the process that has a high operating cost is the dewatering step. Development of a membrane filter that will reduce the cost of the dewatering step is the focus of this proposal. This program develops a new low-cost fouling resistant composite filtration membrane that is not currently available commercially. The nonstick perflouoropolymer layer is combined to the porous filtration membrane in a manner that does not blind the pores or significantly reduce the water transport rate across the membrane, while simultaneously dramatically improving the fouling and chemical resistance of the membrane. During the Phase I project, Compact Membrane Systems will identify the proper membrane support pore size for algae slurry concentration, develop a method to coat the support with the polymeric membrane, design a lab scale concentration system, run the system for a prolonged period of time, and obtain data for flow and water removal rates. The cost of harvesting along with the other major cost components must be substantially reduced in order to make algae oil a viable source of biodiesel fuel. Introduction of a durable fouling resistant filtration membrane will substantially reduce the cost of dewatering, thereby substantially reducing the cost of the harvesting process. The current biodiesel market in United Sates is approximately 1,400 million gallons/year. Assuming conservatively that 10% of the total biodiesel market will be served by algae oil processed by this technology, the anticipated market for algae oil processing in United States is 140 million gallons/year. Based on cost savings of $0.40/gallon from the proposed membrane, the total annual cost savings for processing algae oil in the U.S. is estimated as 56 million dollars.