Attractive Algae Extraction Technologies – An Overview by Biofuels Digest
Attractive Algae Extraction Technologies – An Overview by Biofuels Digest
Popular biofuels magazine Biofuels Digest has made an analysis on algae extraction technologies of various companies and listed 10 attractive ones. As extraction cost is one of the barriers towards commercialization, this analysis would be of useful in identifying viable algae extraction technologies. Here is a brief account on this article published in the Biofuels Digest.
AER Sustainable Energy
Ireland-based ethanol company AER Sustainable Technology, is following enzymatic hydrolysis for the extraction of oil from algae. They claim that their process is a cheap and efficient one, which lyses the algal cell wall and release the oils and sugars.
Diversified Technologies
Diversified Technologies, Massachusetts, announced in February that they have introduced a low-cost, patent-pending extraction system using pulsed electric field (PEF) technology. Diversified estimates this low energy process of lysing algae cells would account for about $0.10/gal of the price of algae-derived biofuel compared to $1.75/gal for conventional drying.
Aurora Algae
Aurora Algae has received US patent for “Systems and Methods for Extracting Lipids from and Dehydrating Wet Algal Biomass”. The process is devised with the idea of dehydrating the algae for the separation of proteins and carbohydrates out of the lipids and water. The method is to centrifuge the algae first and then using a solvent such as acetone, methanol, ethanol, isopropanol, butanone, dimethyl ether, or propionaldehyde to separate out the proteins and carbohydrates from the lipids. After recovering the solvent, water and lipids are separated out as easily as, well, oil and water.
These three are the latest technologies. Here comes a note on technologies that are in a stage of development and deployment.
Algae Venture Systems
Algae Venture Systems’ Solid Liquid Separation (SLS) has been described by ARPA-E as a “potentially transforming innovation”. It is a low energy system, which reduces the dewatering costs by 90%, according to the company. They claimed that their technology could dramatically reduce the cost of dewatering to about $1.92 per ton.
OriginOil
OriginOil’s technology, called Single Step Extraction can be deployed by either dewatering the algae only for converting the biomass to oil or separating the lipids and biomass for other valuable products. Single Step Extraction is currently implemented in MBD Energy’s facility in Australia. The company’s Live Extraction technology separates lipids in a continuous manner from the healed algae after it is milked for oil. The technology is in prototype stage.
New Oil Resources
New Oil Resources developed a process based on thermal depolymerization for algae oil extraction. The technology used hot, pressurized water to treat the biomass. The process is also commonly referred to as hydrothermal liquefaction. According to the company, their technology could process the algae without dewatering and all the carbon could be converted into fuels.
Unitel Technologies
Unitel, an Illinois-based company filed a patent in July 2010, for a technology of making biofuels from algae. The process involves minimal dewatering and completely by-passes the energy-intensive drying and oil extraction steps. The process can be used to make biojet fuel comprised of C10-C15 branched paraffins.
Evodos
Evodos developed in September 2010, an energy-efficient centrifuge for the extraction of algae from water. The technology consists of two steps: first, most of the water in which the algae are growing is removed and next the algae are transformed into a dry paste. The Evodos technology enables the extraction of a solid algae cake with a dry solid content of 31.5%.
University of Michigan – Project I
The project is designed to find out a method to bypass the drying and solvent extraction steps. They described a two-step catalyst-free algae fuel production process. In the first step, wet algal biomass (ca. 80% moisture) reacts in subcritical water to hydrolyze intracellular lipids, conglomerate cells into an easily filterable solid that retains the lipids, and produce a sterile, nutrient-rich aqueous phase. In the second step, the wet fatty acid-rich solids undergo supercritical in situ transesterification (SC-IST/E) with ethanol to produce biodiesel in the form of fatty acid ethyl esters (FAEEs).
University of Michigan – Project II
Interestingly, researchers at the University of Michigan are investigating the possibility of pressure cooking the algae at 300°C for 30 minutes to breakdown the oils, proteins and carbohydrates into a bio-oil which could then be upgraded into a biofuel. The project aims at producing acceptable fuel yields from low-oil content algae strains, as well as eliminating the need for water extraction in algal fuel production.
