Estimates we did at Oilgae suggest that the drying cost using conventional methods will be between $200-$500 per ton of dry biomass, which is humungous, especially so when the cost of biomass production has to be less than $300 per dry ton to be economically competitive with fossil fuels.
This cost can be eliminated by extracting oil directly from the wet biomass bypassing the drying step. Direct-extraction or wet-extraction is basically a water-tolerant downstream process which involves separating oil from the wet algae paste and then subjecting it to transesterfication to produce biodiesel.
Some research institutes that have been working on wet extraction:
University of Michigan
Research studies from the University of Michigan reveal that the direct extraction method will be a feasible option to produce oil directly from wet algal biomass. They have worked on the marine water algae Chlorella vulgaris.
Basically, their process involves two steps:
•The wet algal biomass is reacted with subcritical water to hydrolyze intracellular lipids, conglomerate cells into an easily filterable solid that retained the lipids and produced a sterile, nutrient-rich aqueous phase.
•The wet, fatty acid-rich solids are then subjected to supercritical transesterification with ethanol to produce fatty acid ethyl esters (FAEEs).
Ames Labs / Catalin
•Ames Labs and Catalin – a nano- technology based company which specialize on biofuels have devised a technology that uses sponge-like nanoparticles to extract oil from the algae.
•The process doesn’t harm the algae like other methods being developed, which helps reduce both production costs and the production cycle.
•Once the algal oil is extracted, a separate and proven solid catalyst from Catilin will be used to produce ASTM (American Society for Testing and Materials) and EN certified biodiesel.
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