Chemical and fractional composition of bio-oil obtained from Arthrospira platensis by hydrothermal liquefaction

Abstract

This work is devoted to the study of chemical and fractional composition of the bio-oil obtained from Arthrospira platensis by hydrothermal liquefaction in the temperature range of 240-330 °C. For bio-oil analysis standard elemental analysis, ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT ICR MS) and thermogravimetric analysis were used. It was shown that the yield of bio-oil was increased from 12.4% at 240 °C to 37.2% at 330 °C. With temperature increasing the spectrum of compounds found in bio-oil using FT ICR MS narrowes and moves to the region of low-molecular compounds. It was found that among the components containing nitrogen and oxygen, compounds containing 1 and 2 nitrogen atoms, as well as ON and O2N3 classes, dominate in the bio-oil. With the increase in the temperature of the liquefaction process, classes of compounds containing several oxygen atoms ON, O2N3, O3N2, ON2, transforms into the classes N and N2. By thermogravimetric analysis it was shown that the gasoline fraction (with boiling temperatures up to 200 °C) in bio-oil samples obtained from Arthrospira platensis at 240-330 °C was in the range of 20-22%. The fraction of light-boiling components in bio-oil was slightly decreased when the temperature of hydrothermal process was increased.