Microalgal lipid is being considered as an alternative source of ω-3 polyunsaturated fatty acids (ω-3 PUFAs); however, the extraction of ω-3 PUFA-rich algal lipid still needs further research. In this study, single enzyme and their combinations were screened based on their cell wall disrupting capability and lipid recovery yield, and economical and feasible extraction parameters were determined. Lipid recovery could reach 22.18 ± 0.26 wt% when algae was treated with an 8 : 1 (w/w) algae/cocktail enzyme ratio and a 2 : 1 cellulase/lysozyme mass ratio at 50 °C under stirring for 5 h at a pH of 4.0, and the content of PUFAs was as high as 23.30%. In addition, alkaline pretreatment efficiently facilitates the degradation of algal cell wall in the enzymatic hydrolysis, and it has been verified that cell wall ruptures via two steps: swelling by a weak alkali pretreatment and decomposition by enzymatic hydrolysis. Furthermore, all the extraction operations can take place under facile conditions. These results imply that algal lipid extracted by a weak alkali pretreatment aiding enzymatic hydrolysis, is the most appropriate raw material for ω-3 PUFAs.

In this study, the aromatic-rich fraction from heavy oil was modified by polyacrylic acid and oleic acid to obtain the modified raw materials which were used for producing mesophase pitch via polymerization reaction. First, the properties of modified feedstocks were analyzed by Fourier transform infrared spectrometry (FTIR), simulated distillation, and elemental analysis. The optical texture and molecular and microcrystal structure of the mesophase were characterized by the techniques of polarized optical microscopy, FTIR, 1H nuclear magnetic resonance, X-ray diffraction, and Raman spectroscopy. The influence of alkyl structures contained in modified feedstocks on the preparation of the mesophase was studied. The results suggested that the amounts of alkyl chains in modified raw materials increased first and then decreased with raising the amount of the additives. The short and long alkyl chains in mesophase pitches from modified feedstocks were resulted by treatment of polyacrylic acid and oleic acid, respectively. In addition, the mesophase pitches with finer microcrystal structures, less crystalline imperfection, and high degree of graphitization were generated from modified raw materials. Moreover, an appropriate amount of short alkyl chains or a small number of long alkyl chains was favorable for the formation of a mesophase with a large domain structure, low softening point, high carbon residue, and fine microcrystal structure.

A comprehensive compositional analysis was conducted on biofuel obtained from woody biomass hydroliquefaction in supercritical ethanol with a dispersed Ni-based catalyst. Gas chromatography–mass spectrometry (GC–MS) and 1H nuclear magnetic resonance (NMR) were used to analyze the bio-oil compositions, and the results indicated the presence of carboxylic acid, ethyl ester, aldehyde, ketone, phenol, and its derivatives. As a result of the inherent limitations of these techniques, an intensive compositional characterization of bio-oil was accomplished through Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The results revealed that the dominant oxygen-containing compounds were O2–O13 with double bond equivalent (DBE) values of 1–20 and carbon numbers of 10–25. The minor N1Ox class species with 4–15 carbon numbers and 10–35 DBE were also detected. The use of FT-ICR MS provided an in-depth compositional analysis of liquefaction-derived oil and would improve the understanding of biocrude for further process upgrading.

A novel synthesis method was developed to prepare a silica-supported monoclinic molybdenum dioxide (MoO2/SiO2) catalyst via calcination of molybdenum disulfide (MoS2)/SiO2 in N2 flow with 0.1 vol % O2. MoO2/SiO2 was employed as a catalyst for sawdust hydroliquefaction in ethanol at 320 °C under an initial H2 pressure (IHP) of 2–6 MPa, and the bio-oil yield as high as 72.3% was obtained under an IHP of 6 MPa. The high catalytic activity of MoO2/SiO2 should be attributed to the efficient cleavage of H2 on the surface of highly dispersed MoO2, which shows an unusual metallic characteristic. The obtained bio-oil was analyzed with gas chromatography/mass spectrometry (GC/MS), and the main organic compounds detected by GC/MS were phenolics and ethyl esters.

•Tetralin is firstly utilized as chemical probe to investigate the solvent effects on the sawdust liquefaction.•The higher solvent impact index is consistent with higher sawdust conversion and bio-oil yield.•The temperature and solvent type have an influence on the solvent effect in the liquefaction process.•The analysis results showed that product compositions highly depend on the employed solvents.An innovative reference approach was developed to investigate the solvent effects on the liquefaction of sawdust by using tetralin as a chemical probe, and the corresponding solvent impact index was defined in this study. The influence of reaction conditions including reaction temperature and solvent types on solvent impact index were discussed. It was found that larger solvent impact index corresponds to improved sawdust conversion and higher bio-oil yield. The liquid and gaseous products obtained were characterized by 1H nuclear magnetic resonance (1H NMR), gas chromatography (GC), and elemental analysis (EA). The component of products highly depended on the employed solvents.

In this work, a series of solid desulfurizers were prepared via loading of an inorganic alkali on activated carbon (AC). The optimal synthetic procedure of the solid desulfurizer is to pretreat AC with nitric acid (68.0 wt %) for 4 h and then impregnate the sample in a 0.02 g/mL NaHCO3 aqueous solution at 35 °C for 2 h. Finally, this solid adsorbent desulfurizer was calcined at 500 °C for 4 h, and referred to as NC-AC. This solid desulfurizer was used to treat Saudi Arabian crude oil with a mass ratio of 30:1 (crude oil:NC-AC) at 55 °C for 3.5 h. A desulfurization efficiency as high as 32.4 wt % was achieved with optimized NC-AC. The NC-AC samples had larger pore diameters and evenly distributed alkali leading to high desulfurization efficiency. The desulfurization mechanisms of the AC supported desulfurizer were analyzed, indicating that both physical and chemical adsorption occurred on the desulfurizer. This desulfurizer also has good performance to adsorb thiophenes, alkylthiophene, and benzothiophenes in the crude oil, and H2S, thioether and mercaptan in the gasoline fraction.

The effect of different solvents on the hydro liquefaction of sawdust with ionic liquid nickel catalyst was investigated. Subsequently, effects of different parameters on the liquefaction behavior of sawdust were explored with the suitable solvent. The optimized results with bio-oil yield of 58.51% were obtained using ethanol solvent at 320 °C and 10 min with solvent/biomass of 10 mL/g. The higher heating values of the bio-oil was 26.02 MJ·kg–1, which was higher than that of sawdust. According to the GC–MS analysis, the major compound in light oil was ethyl esters, and the components of heavy oil were mainly consisted of ethylbenzene other benzene derivatives.

Venezuela heavy oil under various hydrogen pressures has been hydrocracked to investigate the variation of asphaltene components during reaction. Asphaltenes have been isolated from the product and analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and nuclear magnetic resonance (NMR). The experimental data revealed that the interlamellar spacing and interchain spacing of the asphaltenes increased while the layer diameter decreased with the hydrogen pressure increasing. At the same time, the amount of aromatic carbon and alkyl carbon of the asphaltenes decreased gradually and the amount of naphthenic carbon increased. As the hydrogen pressure increased, the substitution ratio and the condensation degree parameter (HAU/CA) of the aromatic system in the periphery increased gradually and the replacement index and peri-position condensation index of asphaltenes decreased obviously.

The hydrodesulfurization (HDS) of thiophene and its derivatives by Mo-based catalysts shows significant economic benefits in crude oil processing and refining. Several Mo-based catalysts have been successfully used for HDS reaction despite of unclear catalytic mechanism. Thereby we use in situ FT-IR technique to investigate the adsorption of thiophene on the surface of supported and dispersed sulfided Mo catalysts. The results demonstrate that thiophene can be adsorbed on the catalyst surface through coordination of S atom, CC and CC with the unsaturated Mod+ sites located on the edge planes of MoS2-like structures, forming four different complexes. These adsorption manners were also proved by theoretical calculation with the density functional method (DFT). The calculated binding energy of η2(S) complex is larger than other complexes, suggesting that thiophene preferred to being adsorbed on the catalyst surface through the coordination of CC with unsaturated Mod+ sites. The formation of coordinated complexes can decrease the aromaticity of thiophene ring and weaken CS bond, which could promote the HDS reaction.Highlights► The adsorption of thiophene on the surface of sulfided Mo catalysts was theoretically and experimentally investigated. ► In situ FTIR technique confirmed the weak chemical absorption of thiophene on the catalyst surface. ► Four complexes were formed through the coordination of S, CC and CC with unsaturated Mod+ sites. ► The larger binding energy suggests the favorable absorption is through the coordination of CC with unsaturated Mod+ sites.