Hydrothermal liquefaction of high- and low-lipid algae: Mass and energy balances. (June 2018)

• Record Type: Journal Article
• Authors: Cheng, Feng; Cui, Zheng; Mallick, Kwonit; Nirmalakhandan, Nagamany; Brewer, Catherine E.
• Is Part Of: Bioresource technology. Volume 258(2018)
• Page Start: 158
• Page End: 167
• Publication Date: 2018-06
• Subjects: Hydrothermal liquefaction -- Bio-crude oil -- High protein algae -- Mass balance -- Energy balance; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2018.02.100
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: G. sulphuraria needs more severe HTL reaction conditions to produce bio-crude oil. Algae with high lipid contents allow for greater energy recovery in bio-crude oils. Higher solids loadings of algae produce similar oil yields and require less energy. Up to half of the energy in G. sulphuraria can be recovered in HTL bio-crude oil. Abstract: Hydrothermal liquefaction (HTL) of high-lipid microalgae Nannochloropsis salina ( N. salina ) and low-lipid microalgae Galdieria sulphuraria ( G. sulphuraria ) were run under subcritical conditions (310–350 °C and 10–17 MPa) in a 1.8 L batch autoclave system. HTL mass and energy balances for both species were compared under different operating conditions to predict the optimum reaction conditions for new algae strains based on their feedstock composition. Bio-crude oils and chars were characterized by bomb calorimetry, elemental analysis, inductively coupled plasma optical emission spectrometry (ICP-OES), and thermogravimetric analysis (TGA). Under the optimized conditions, 59 wt% and 31 wt% bio-crude oil yields were obtained from HTL of N. salina and G. sulphuraria, while 85% and 59% of the feedstock energy were partitioned into N. salina -derived and G. sulphuraria -derived bio-crude oils, respectively. More favorable energy balances were related to shorter reaction times and higher algal solid contents.