Production of low-nitrogen bio-crude oils from microalgae pre-treated with pre-cooled NaOH/urea solution. (15th October 2017)

• Record Type: Journal Article
• Authors: Hu, Yulin; Feng, Shanghuan; Xu, Chunbao (Charles); Bassi, Amarjeet
• Is Part Of: Fuel. Volume 206(2017)
• Page Start: 300
• Page End: 306
• Publication Date: 2017-10-15
• Subjects: Microalgae -- Pre-treatment -- NaOH/urea solution -- Diluted acid -- Hydrothermal liquefaction -- Bio-crude oil -- Solid residue; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2017.06.021
• Languages: English
• ISSNs: 0016-2361

Abstract

Abstract: In this study, a novel two-stage hydrothermal liquefaction (HTL) process was employed to produce low-nitrogen bio-crude oils from microalgae, involving pre-treatment of the microalgae with a pre-cooled NaOH/urea solution or a dilute acid and HTL of the pre-treated algal feedstock at 250°C for 10–50 min. The results indicated that the pre-treatment with a pre-cooled NaOH/urea solution effectively removed carbohydrates and protein from the raw microalgae, leading to a decrease in carbohydrates and protein content by 12 wt% and 10 wt% (both absolute values), respectively, while retaining 70 wt% of the solid mass, corresponding to as high as 82% carbohydrates removal efficiency and 40% protein removal efficiency. The two-stage HTL process slightly increased the overall bio-crude oil yields relative to the conventional single-stage HTL process, and the bio-crude oils obtained from the two–stage HTL process have a better quality than those obtained from the single-stage HTL, in terms of lower nitrogen and oxygen levels and higher energy content.