Effect of harvesting methods on the energy requirement of Tetraselmis sp. biomass production and biocrude yield and quality.

Highlights • The energy requirement for harvesting Tetraselmis sp. biomass was 0.49–4.65 MJ/kg. • Harvesting technique affected the microalgal biomass quality. • Microalgal biocrude yield and characteristic varied based on harvesting technique. • Excess Al in electrocoagulation and alum harvested biomass increased biocrude yield. • All microalgal biocrude samples had higher metal contents compared to petrocrude. Abstract A halo-tolerant Tetraselmis sp. was grown in a 100,000 L raceway pond in the Qatari desert environment. As the biomass density reached 0.679 g/L, after 7 days, five different harvesting methods (i.e., cross-flow filtration, electrocoagulation, and coagulation-flocculation by FeCl 3 , NaOH, and alum) were applied to harvest the biomass. Hydrothermal liquefaction, for all the harvested biomass, was conducted at 350 °C for 30 mins in 10 mL Swagelok unions. The biocrude yield from cross-flow processed biomass (i.e., control) was 50.8%. Biocrude yield from electrocoagulation and alum processed biomass were 62.7% and 60.4% respectively where aluminum could have a catalytic effect. Biocrude yield from FeCl 3 and NaOH processed biomass were 42.9% and 19.8% respectively. The total fraction of alkenes and alkanes was higher in the biocrude obtained from alum-harvested biomass, compared to other biocrude samples. However, the transition of metal species from biomass to biocrude was very low in all the biocrudes. [ABSTRACT FROM AUTHOR]