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.

The oxidation–extraction desulfurization of Saudi Arabian crudes was conducted with hydrogen peroxide–acetic acid oxidation system. The selection of extractant, the optimization of oxidation–extraction conditions, and the exploration of desulfurization mechanism were studied. As DMF was used as the extractant, the optimal desulfurization rate of 35.11 % and oil recovery of 95 % were obtained at 70 °C with the molar ratio of peracetic acid to sulfur of 8:1, the molar ratio of acetic acid to hydrogen peroxide of 2:1 and the volume ratio of extractant to oil of 1:1. The desulfurization effect of different fractions in the treated Saudi Arabian crudes was found to obey the following order: gasoline–diesel fraction >VGO fraction >VR fraction, due to different types and structures of sulfur compounds. The oil quality was less affected and most sulfides were mainly extracted via DMF.

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Comparative studies in carbonization behaviors of petroleum pitch (SS70 pitch) and SS70-pitch–additive mixtures were conducted to develop a better understanding of the modified mechanisms of additives. The carbonization of solvent fractions in SS70 pitch was also investigated to reveal the relationships among solvent fractions and the additives. The characterization of resultant solid products by X-ray diffraction and scanning electron microscope analysis showed that samples obtained from co-carbonization of SS70–aromatic oil (P1) and SS70–aromatics enriched fractions of FCC slurry (P2) mixtures respectively had higher stacking layer numbers of mesogens and flatter morphology than those of specimens produced by carbonization of SS70 pitch and SS70–deasphalt oil (P3) mixtures. Adding additives P1 and P2 into SS70 pitch lowered not only the rates of carbonization but also the aromaticity and size of aromatic molecules in toluene insolubles formed in the early stage of carbonization, both jointly contributing to the formation of well-developed mesophase. The asphaltenes of SS70 pitch were prone to forming the poorly developed mesophase due to its high reactivity and also interfered with the carbonized performance of maltenes. Additives P1 and P2 played the “dominant partner effect” on mesophase development by providing physical fluidity of the reaction system and some chemical stability for asphaltenes via their dilution effect and H-transfer reactions.

In this work, aluminum and iron existing in coal fly ash were extracted by the method of hydrochloric acid leaching. Effects of solid-liquid ratio, reaction temperature, reaction time, acid concentration, and raw ash mesh on recovery efficiencies of AlO and FeO were investigated. X-ray diffraction analysis indicated that anhydrite, hematite, mullite and quartz were the dominant minerals in the raw fly ash sample. X-ray fluorescence technique was applied to determine the mass fractions of chemical components in the raw ash and leached residues, while the concentrations of AlO and FeO in leaching solutions were measured by titration method. The optimal recovery efficiencies of AlO and FeO, obtained under the reaction condition of 95°C, 5 h, acid concentration of 20 wt.%, a solid-liquid ratio of 1:3.5 and raw ash mesh of 400, were 42.75% and 35.10%, respectively. After removing the leached residues, the leaching solutions were employed to manufacture flocculants of polymeric aluminum ferric chloride for treating the oil recovery wastewater from polymer flooding, which possessed high contents of suspended solids (SS) and oils. Microfiltration membrane and ultraviolet spectrophotometer were utilized to determine the contents of SS and oils in water samples. Through adjusting Al/Fe molar ratio to 20:1 and basicity to 70%, the maximum removing efficiencies of SS and oils can be achieved, respectively 96.1% and 91.5%. Moreover, increasing the iron content and basicity of flocculants within certain ranges contributed to improving the settling characteristic of flocs.