An investigation of reaction pathways of hydrothermal liquefaction using Chlorella pyrenoidosa and Spirulina platensis

• Published in: Energy conversion and management Vol. 96; pp. 330 - 339
• Main Authors: Gai, Chao, Zhang, Yuanhui, Chen, Wan-Ting, Zhang, Peng, Dong, Yuping
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.05.2015
• Subjects: Aliphatic compounds; Arthrospira platensis; Biofuel; biofuels; carbohydrates; Chemical composition; Chlorella; Chlorella pyrenoidosa; Concentration (composition); Economic conditions; Functional groups; Hydrothermal liquefaction; lipids; Liquefaction; Low-lipid microalgae; microalgae; moieties; Networks; organic compounds; Pathways; spectral analysis; Spirulina; Spirulina platensis; temperature; Low-lipid microalgae; Chlorella; Spirulina; Biofuel; Hydrothermal liquefaction
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2015.02.056

•Hydrothermal liquefaction (HTL) of microalgae C. pyrenoidosa and S. platensis.•Characterization of bio-crude oils and aqueous fractions during HTL process.•General reaction network for HTL of C. pyrenoidosa and S. platensis.•Specific reaction pathways for HTL of lipid, protein and non-fibrous carbohydrate. Low-lipid microalgae can be successfully converted to bio-crude oil in a hydrothermal liquefaction (HTL) environment. This study examined the behavior of hydrothermal liquefaction of two low-lipid content microalgae in subcritical water between 200°C and 320°C at 20°C intervals. Under these conditions, the chemical composition and functional groups for the bio-crude oil and aqueous fraction were analyzed. Results indicated that reaction temperature greatly affected the distribution of chemical composition and functional groups of HTL bio-crude oil and aqueous fraction. The bio-crude oil with a higher percentage of aliphatic functional groups was obtained at higher reaction temperatures (280–320°C). Besides, the aqueous fraction recovered under the same operating conditions had a lower concentration of nitrogenous organic compounds (NOCs) with two or more methyl groups. The general reaction network for HTL of low-lipid microalgae was proposed. The specific reaction pathways for microalgae substrates were analyzed in terms of lipid, protein and non-fibrous carbohydrate based on the spectral analysis.