Hydrothermal liquefaction of high- and low-lipid algae: Mass and energy balances

Feng Cheng; Zheng Cui; Kwonit Mallick; Nagamany Nirmalakhandan; Catherine E Brewer

doi:10.1016/j.biortech.2018.02.100

Hydrothermal liquefaction of high- and low-lipid algae: Mass and energy balances

Bioresour Technol. 2018 Jun:258:158-167. doi: 10.1016/j.biortech.2018.02.100. Epub 2018 Feb 24.

Authors

Feng Cheng¹, Zheng Cui¹, Kwonit Mallick¹, Nagamany Nirmalakhandan², Catherine E Brewer³

Affiliations

¹ Department of Chemical and Materials Engineering, New Mexico State University, P.O. Box 30001 MSC 3805, Las Cruces, NM 88003, USA.
² Department of Civil Engineering, New Mexico State University, P.O. Box 30001 MSC 3CE, Las Cruces, NM 88003, USA.
³ Department of Chemical and Materials Engineering, New Mexico State University, P.O. Box 30001 MSC 3805, Las Cruces, NM 88003, USA. Electronic address: cbrewer@nmsu.edu.

PMID: 29525590
DOI: 10.1016/j.biortech.2018.02.100

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.

Keywords: Bio-crude oil; Energy balance; High protein algae; Hydrothermal liquefaction; Mass balance.

MeSH terms

Biofuels*
Gas Chromatography-Mass Spectrometry
Lipids
Microalgae*
Temperature
Water

Substances

Biofuels
Lipids
Water