The present paper reports on the conversion of spent lubricating oil (SLO) into useful fuel-like products through two-stage pyrolysis. Liquid pyrolysates (LPs) from the first stage were obtained using prebaked clay (PBC) as adsorbent and subjected to second stage pyrolysis over coal ash (CA) as catalyst. The PBC and CA were characterized by using morphological, elemental, surface, and crystallographic properties. The influence of CA concentration on the yield of LPs and their compositions in terms of hydrocarbon range and hydrocarbon group type's distributions were studied. Fuel properties such as density, specific gravity, API gravity, ash content, kinematic viscosity, pour point, aniline point, diesel index, cetane number, and calorific value of the thermally derived pyrolysate (TDLP) as well the catalytically derived liquid pyrolysate (CDLP) in comparison with the ASTM standard values were also studied. The results indicate that the CA when used in low concentration exhibited good activity and selectivity toward formation of the LPs having fuel value comparable with diesel fuel.

The present study was planned to explore the selective desulphurization efficiency of the acid-modified activated charcoal (AC) as an adsorbent. The oil samples selected were the model oil and the commercial kerosene & diesel. The adsorption capacity of the AC was evaluated for the removal of one of the sulfur analogs i.e. dibenzothiophene (DBT) present in the fuel samples under a set of experimental conditions. The kinetics and thermodynamics of the DBT desulphurization were studied. It was observed that the adsorption firmly followed pseudo-second order kinetic model. Moreover, the experimental value of the amount of DBT adsorbed at equilibrium "q e " was nearly equal to the value calculated from the pseudo-second order kinetic model. Langmuir and Freundlich adsorption isotherm models were applied and the experimental data best fitted with the Langmuir and Freundlich adsorption isotherm models. Compared to other commercially available adsorbents, the acid-modified AC was found to be cost-effective, highly efficient and selective for the DBT removal from the model as well as real petroleum based oils.

Gas chromatography–mass spectrometry (GC–MS) was used to monitor the thermo-oxidative degradation of the plain and additized mineral base oil (MBO) samples. Antioxidants used were MeOH extracts of the rice husk (RHE) and saw dust (SDE). The oxidation was performed for 6 h at 200 °C according to the modified Institute of Petroleum (IP) method. The results indicate that the additized MBO samples inhibited thermo-oxidation compared to the plain sample. Among the two antioxidants, the RHE showed excellent antioxidant potential compared to the SDE.

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This paper focuses on evaluating the potential of sawdust-derived antioxidants in oxidative stability of the lubricant oil samples monitored through gas chromatography−mass spectrometry (GC−MS). The plain and antioxidants-spiked oil samples were subjected to artificial aging at 100 °C for 6 h in a flow of air (10 L h −1 ). The results indicate that the antioxidants under study imparted thermo-oxidative stabilities to the oil compared to the plain sample and exhibited good antioxidants potential at 100 °C.

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The present work addresses the catalytic conversion of spent lubricating oil (SLO) into reusable diesel-like product over laboratory-prepared barium ferrite (abbreviated as BF, formula BaFe 2 O 4 ) using pyrolytic distillation. Soot, carbon, water, and other detrital contaminants were removed from SLO by prior treatment using pre-baked clay as adsorbent. The BF was characterized by scanning electron microscopy, energy-dispersive X-ray scattering, X-ray diffractometry, and surface area analysis and used in the concentration range of 1−5 wt%. The influence of BF concentration on overall conversion (OC) and yields of liquid fraction (LF), gas (G), and solid residue (SR) was studied in comparison with the thermal uncatalyzed run. A catalyst loading of 5 wt% was found to be optimum, giving yields of 97.67 wt% OC, 92.91 wt% LF, 2.33 wt% G, and 4.76 wt% SR. Fourier transform infrared and gas chromatographic−mass spectrometric analyses showed the preponderance of aliphatic (79.38%) and olefinic (11.18%) hydrocarbons in the derived LF. The fuel properties of the derived fraction were also investigated using ASTM/IP standard methods. The results showed that a 5 wt% concentration of BF possessed high activity and selectivity toward formation of diesel-range hydrocarbons in appreciable yields.