F. Khan

The chemical composition of catalytic air blown asphalt

Abstract Air blowing of paving grade asphalt has been carried out to produce industrial grade asphalt. Chemical changes during air blowing of asphalt, in the presence of transition metal salts, have been evaluated by adsorption-desorption chromatography. The elemental composition and structural parameters based on ultraviolet (u.v.) and nuclear magnetic resonance (n.m.r.) spectra indicate that straight chain hydrocarbons are converted to naphthenes, which in turn are dehydrogenated to form aromatic hydrocarbons during air blowing. The blown product becomes more complex and condensed leading to an increase in molecular weight. These changes are accelerated by an active catalyst. A general transformation mechanism has been proposed.

Production of Low Metal Content Re-refined Lubricating Oil

Abstract A number of metals are found in used lubricating oil. In this article, performance of solvent extraction followed by adsorption on magnesite has been studied for removal of metals from used oil. The suggested process is one of the efficient methods to remove not only sludge, but also the metals either present in the lubricating oil as additives or picked up by the oil during its working life. The re-refined oil has metal content comparable with base oil. In some cases, even lower metal content has been observed.

Factors influencing asphalt oxidation

Abstract The effects on the air blowing reaction of variables such as reactor design, temperature, air rate and time were studied and optimized to obtain high softening point industrial asphalt from paving grade asphalt. The reactions were followed by measuring softening point and penetration at regular intervals.

Optimized liquid-liquid extractive rerefining of spent lubricants.

Central composite design methodology has been employed to model the sludge yield data obtained during liquid-liquid extractive rerefining of spent lubricants using an alcohol (1-butanol) and a ketone (methyl ethyl ketone) as prospective solvents. The study has resulted in two reasonably accurate multivariate process models that relate the sludge yield (R 2 = 0.9065 and 0.9072 for alcohol and ketone, resp.) to process variables (settling time t, operating temperature T, and oil to solvent ratio r). Construction of such models has allowed the maximization of the sludge yield (more than 8% and 3% in case of alcohol and ketone, resp.) so that the extraction of useable oil components from spent lubricants can economically be performed under extremely mild conditions (t = 16.7 h, T = 10°C, and r = 2) and fairly moderate conditions (t = 26.6 h, T = 10°C, and r = 5) established for the alcohol and ketone correspondingly. Based on these performance parameters alcohol appears to be superior over ketone for this extraction process. Additionally extractive treatment results in oil stocks with lesser quantity of environmentally hazardous polyaromatic hydrocarbons that are largely left in the separated sludge.

The Characterization of Indigenous Magnesite: A Prospective Adsorbent for the Re-Refining of Used Lubricating Oil

Raw magnesite is slightly porous but its porosity could be increased on heating at and above 500°C. Its adsorption characteristics were investigated for various activation temperatures, times and particle sizes. Maximum adsorption capacity was found for 100–230-mesh magnesite particles activated at 500°C for 2 h. This has produced low color index re-refined oil. One of the economical features is the reproducibility of the results after regeneration of the spent magnesite samples. An excellent feature of the adsorbent is the efficient removal capability of aromatics especially PAH, which is supported by UV and FTIR studies of oils.

The Adsorption Capability of Reactivated Magnesite for Re-refining Spent Lubricants

This study evaluates the possibility of the cyclic use of magnesite by subjecting the reactivated adsorbent to surface area determination and scanning electron microscopy. Both these analyses show that the reactivated adsorbent is comparable to the fresh adsorbent, produced from raw magnesite, in porosity that plays the major role in the removal of noxious substances from spent lubricants. The adsorption ability of the reactivated adsorbent has been further testified through spectroscopic analyses of the percolated oil that exhibit marked decrease in polyaromatic hydrocarbons, metal content, and oxygenates that impart rancid odor in spent lubricants.

Liquid-Phase Homogeneous Catalytic Oxidation of Gas Oil: Elucidation of Complex Chemical Transformation Network

An attempt has been made to elucidate the extremely complex chemical changes that take place when gas oils (middle distillates such as high speed diesel) are subjected to liquid phase homogeneous oxidative processing in the presence of the redox couple Co(III)/Co(II). For this purpose dilute solutions of gas oil in wet acetic acid have been treated with air under carefully controlled conditions of temperature, pressure and air flow rate. Reaction products are extracted in chloroform from an ice cold aqueous solution of the reaction mixture. Both instrumental (FTIR) and kinetic analyses endorse each other and thereby prove the sequential nature of the reaction resulting in the formation of diverse products through decomposition of the intermediate hydroperoxides, which are unstable in the presence of the catalytic redox couple Co(III)/Co(II).

Effect of catalysts on effluents during air blowing of asphalt

Abstract Air blowing of asphalt was performed in presence of catalysts. The effluents (distillate) obtained during air blowing were analyzed to see the effect of catalysts on them. This study investigates the effluents in detail, using physical and chemical methods. Catalysts used were metallic chlorides in varying quantities and also in combination with manganese dioxide. The aim of using different catalysts was to develop a suitable catalyst, which can perform hardening of asphalt at par with other available catalyst, at the same time keeping the effluents relatively low and free of acidic gases. These acidic gases decrease the life of the plant and cause environmental problems. During a 15 h air oxidation period, it was observed that for feed I asphalt the physical (specific gravity & viscosity) and chemical (acidity & composition) properties of the effluent oils, were effected by the catalysts. Amount of effluents were different for different catalysts. Saturate contents of the effluent were increased due to catalyst, while naphthalene and polar aromatic decreased. Effluents were free of asphaltene. The variation in the properties of effluents obtained during feed asphalts II and III air blowing, were not so distinct than with feed I. It indicates that the extent of changes in the properties of effluents depends on the composition of feedstock. Effluent oils were investigated by instrumental analytical techniques such as GLC, UV. Some of the properties of blown asphalt are also reported.