Process Design and Economics for the Conversion of Algal Biomass to Biofuels: Algal Biomass Fractionation to Lipid-and Carbohydrate-Derived Fuel Products

Energy use and greenhouse gas emissions from an algae fractionation process for producing renewable diesel

“…The stream flows were used for equipment sizing and associated costs. Details are in Davis et al [6], but in summary, this study established that the fractionation approach could achieve a selling price of $4.35 per gallon of gasoline equivalent (GGE) in 2011 dollars for a high-lipid (41 wt%) Scenedesmus feedstock and $5.04/GGE for a lowerlipid (27 wt%) Scenedesmus feedstock if projected improvements in process operating conditions and conversion yields were achieved. Although Davis et al [6] considered ethanol production, the carbohydrate fraction could, in principle, be converted to other fuels or higher value products.…”

“…This study presents an LCA of energy use and greenhouse gas emissions for algal biofuels produced via the fractionation process as modeled by Davis et al [6]. The LCA considered all operations in the fuel pathway, including upstream material and energy provisioning operations, cultivation, and final fuel use.…”

“…The Aspen model of the fractionation process in [6] considered only the conversion of 20 wt% dewatered algae biomass to fuel intermediates plus upgrading the lipids to RD blendstock. The model included all recycle loops, co-generation, heat integration, and waste treatment and calculated net mass and energy inputs.…”

“…Davis et al [6] performed a techno-economic analysis (TEA) of this pathway via a discounted cash flow rate of return analysis that determined the minimum fuel selling price required to achieve a zero net present value under a set of financial assumptions and based upon estimates of capital and operating expenses [6]. That study was based upon a mass-and energy-balanced Aspen Plus computer model that determined stream flows, utility demands, and material inputs, which is summarized in Fig.…”

Sustainable and Efficient Pathways for Bioenergy Recovery from Low-Value Process Streams via Bioelectrochemical Systems in Biorefineries

“…Conversion of algal biomass to hydrocarbon blendstock has been modeled via a lipid-extraction step to remove the non-lipid component, followed by hydrotreatment of the lipids to generate renewable diesel blendstock (RDB) [34]. In addition, ethanol is produced via fermentation of the non-lipid component and electricity is generated from anaerobic digestion of waste components and combined heat and power system (CHP) ( Figure 5A).…”