Valorization of algal biomass is often limited by its low lipid content. Here, different alcohols: ethanol, isopropanol, and glycerol, were studied as co-solvents to improve the conversion efficiency of a lipid-poor microalgae, Galdieria sulphuraria, by hydrothermal liquefaction. Bio-crude oil yield increases, from 13 to 73 wt% (on dry algae basis), were attributed to the alcohols facilitating the transfer of algal protein-derived fragments from the aqueous phase into the oil phase.
View Article and Find Full Text PDFA pilot-scale continuous flow reactor (CFR) was modified for hydrothermal liquefaction (HTL) of algae slurry under subcritical conditions to investigate the feasibility of scaling up from batch to continuous processing. Modifications included a novel dual filter system that can remove solids at system pressure and temperature, and undergo in-situ cleaning. Commissioning was carried out to address potential particle settling and clogging problems, and to estimate reactor transport characteristics.
View Article and Find Full Text PDFTo explore the feasibility of scaling up hydrothermal liquefaction (HTL) of algal biomass, a pilot-scale continuous flow reactor (CFR) was operated to produce bio-crude oil from algal biomass cultivated in urban wastewater. The CFR system ran algal slurry (5 wt.% solids loading) at 350 °C and 17 MPa for 4 h without any clogging issues.
View Article and Find Full Text PDFTwo strains of Galdieria sulphuraria algae, 5587.1 and SOOS, were grown on municipal wastewater to develop energy-positive treatment systems. Hydrothermal liquefaction (HTL) of 5-10 wt% algal biomass solids was conducted at 310-350 °C for 5-60 min to produce bio-crude oil.
View Article and Find Full Text PDFHydrothermal liquefaction (HTL) is a thermochemical process for the wet conversion of oleaginous microorganisms and other biomass and carbon rich feedstocks to biofuels under subcritical conditions. It is a novel green process that produces biocrude as a primary product along with other by-products which include gases, aqueous phase coproduct (ACP) and solid residues. Here we describe in detail the protocols for the conversion of biomass to biocrude through HTL and separation, quantification and analyses of HTL products.
View Article and Find Full Text PDFSweet sorghum has become a promising alternative feedstock for biofuel production because it can be grown under reduced inputs, responds to stress more efficiently than traditional crops, and has large biomass production potential. A three-year field study was conducted to evaluate three cultivars of sweet sorghum as bioenergy crops in the Southeast United States (Fort Valley, Georgia): Dale, M81 E and Theis. Parameters evaluated were: plant density, stalk height, and diameter, number of nodes, biomass yield, juice yield, °Bx, sugar production, and theoretical ethanol yields.
View Article and Find Full Text PDFBackground: Oleaginous microorganisms are attractive feedstock for production of liquid biofuels. Direct hydrothermal liquefaction (HTL) is an efficient route that converts whole, wet biomass into an energy-dense liquid fuel precursor, called 'biocrude'. HTL represents a promising alternative to conventional lipid extraction methods as it does not require a dry feedstock or additional steps for lipid extraction.
View Article and Find Full Text PDFThe economic feasibility and environmental impact is investigated for the conversion of agricultural waste, delactosed whey permeate, through yeast fermentation to a renewable diesel via hydrothermal liquefaction. Process feasibility was demonstrated at laboratory-scale with data leveraged to validate systems models used to perform industrial-scale economic and environmental impact analyses. Results show a minimum fuel selling price of $4.
View Article and Find Full Text PDFThis study investigated the optimum thermochemical liquefaction (TCL) operating conditions for producing biocrude from Spirulina platensis. TCL experiments were performed at various temperatures (200-380°C), holding times (0-120 min), and solids concentrations (10-50%). TCL conversion at 350°C, 60 min holding time and 20% solids concentration produced the highest biocrude yield of 39.
View Article and Find Full Text PDFThis study characterized the ACP stream from the TCL of Spirulina and evaluated its potential as a nutrient source for cultivation of microalgae. TCL of 100 g of dry Spirulina resulted in 40% BioOil and 429.80% ACP.
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