New Mixing-Technology, Scalable, Low-Energy-Input Photobioreactors For Greatly Increased Algal Growth Rates And Yields

A unique patent-pending technology has been invented that dramatically increases fluid mixingin tubular photobioreactors (PBRs). This design called "Growth Enhancing Mixing Spectrum"(GEMS) creates eddies that generate efficient transverse fluid flow across PBR tubes usingvery low mean flow rates and thus very low input energies. We will test this mixing strategy forthe first time on growth rates and biomass yields of microalgae in several configurations ofGEMS PBRs relative to standard smooth-tube PBRs. Its physics involves the interaction of fluidflow with static alterations of tube walls that extend deep into the main pipe flow beyond theviscous region. These create unsteady three-dimensional flow separations that divert energy intocrossflows. This separation phenomenon is inherently scalable and uses no moving parts.Studies will be performed in four 10-liter GEMS PBRs to test algal productivity over a range ofparameters. We anticipate productivities approaching those in optimal laboratory cultures andsubstantially greater (~5x or more) than in best mass-scale systems. Our best 10-liter design willbe scaled to 500 liters to test productivity in a GEMS PBR ready for Phase II development andcommercialization. These GEMS systems hold game-changing potential for economic recoveryof CO2 effluents from ethanol plants power plants and other sources for foods feeds and fuelsthat will benefit agriculture and industry. We further envision deployment of soft pipe GEMSPBRs directly in farm-field furrows with no additional land requirements as added agriculturalprofit centers.