2.4. Products analysis
The bio-oil properties were characterized using the methodology described in by Du et al. (2011), which is depicted as follows: An RVA Super 4 Visco Analyzer (Newport Scientific Pty Ltd., Australia) was used to analyze the viscosity of the bio-oil. An elemental analyzer (CE-440, Exerter Analytical Inc., USA) was used to examine the elemental composition, and to calculate the higher heating value (HHV), according to Friedl et al. (2005). The compositions of the liquid products were identified using an Agilent 7890–5975C gas chromatography/mass spectrometer with an HP-5 MS capillary column. Helium was used as the carrier gas at the fiow rate of 1.2 ml/min. The injection size was 1 ll, with a split ratio of 1:10. The initial temperature of the oven was 40 C, it was held for 3 min, and then it was increased to 290 C at the rate of 5 C/min, and then held for 5 min, while the detector and injector were conserved at a constant temperature of 230 C and 250 C, respectively. The National Institute of Standards and Technology (NIST) mass spectral data library was used to compare their mass spectra with those from identified compounds. The moisture content was determined by a Karl-Fischer titrator. A Varian Micro-GC CP4900/thermal conductivity detector (TCD) with a 5A molecular