Y.K. Sharma

Studies on the oxidative behavior of base oils and their chromatographic fractions

Abstract A modified IP 306 test procedure is used to study the high temperature liquid phase oxidation of five base oils and their hydrocarbon type subfractions. The base oils are selected so as to cover a wide range of physiochemical characteristics. Qualitative as well as quantitative analysis of the base oils and their fractions were done using chromatographic (column, HPLC) and spectroscopic (MS, NMR, FTIR) techniques to gain a better understanding of their compositional and structural details. Oxidized materials were also studied and structural changes identified as a result of thermal oxidation. Relative oxidative degradation of different base oils is discussed in terms of their NMR derived structural models. The results indicate that polyaromatic and naphthenoaromatic compounds undergo more oxidative degradation than saturated molecules. The oxygenated polar compounds and deposits formed are mainly derived from aromatic structures, which decreases as weight percent of the total base fluid as oxidation progresses. Alkyl substituted aromatic structures showed larger decrease in chain length than purely paraffin (n- and iso-) compounds during oxidation. Spectroscopic data also indicated that alkylation of aromatics is mainly through alkyl radicals generated from long chain alkyl aromatics.

The Detection of Kerosene as an Adulterant in Gasoline

Abstract Fuel adulteration is associated with environmental pollution, engine performance, and tax loss. Different key characteristics of gasoline were tested using an American Society for Testing and Materials/Institute of Petroleum/Indian Standards (ASTM/IP/IS) method. The results indicate that there is a large fluctuation of fuel properties among the oil marketing companies. In this study, three different grades of gasoline samples were adulterated with 5, 7, and 10% kerosene. These samples were analyzed for the following characteristics to detect adulterants in commercial gasoline: chromatographic analysis, atmospheric distillation (ASTM D 86-1996), and the filter paper test. The first two methods are scientific approaches to detecting adulterants in gasoline and the third is useful in retail outlets. This method has been given emphasis to detect public distribution system (PDS) kerosene as an adulterant in commercial gasoline; gasoline is frequently adulterated with PDS kerosene in Asian countries due to its low cost.

The production and evaluation of bio-oil obtained from the jatropha curcas cake.

Jatropha curcas cake has been studied to produce the bio-oil in a fixed bed pyrolysis unit (slow pyrolysis). The effect of pyrolysis temperature on the product yield and composition was investigated. The highest yield of bio-oil was obtained at 550°C with the heating rate of 5°C/min for the particle size of 0.5–0.8 mm. The physicochemical characteristics of optimum (maximum yield) bio-oil have been completed. The empirical formula of the bio-oil with a calorific value of 25.91 MJ/kg is C23.19 H53.53 N O10.78. The physicochemical characterization studies of the bio-oil showed that the bio-oil obtained from the jatropha curcas cake might be a valuable source for conventional fuel. Chemical composition of the bio-oil has been also investigated by 1H and 13C NMR spectroscopy.

The Instability of Storage of Middle Distillate Fuels: A Review

Abstract The author reviews the research studies that have been so far carried out and reported in the literature on the stability of middle distillate fuels. The emphasis is mainly given to understand the stability of diesel fuels. It has been divided into five principle sections: (a) Introduction, (b) Methods for Determination of Fuel Stability, (c) Mechanism of Degradation, (d) Composition of Total Gum, and (e) Current Status of Methods to Improve Fuel Stability. The introduction provides information of in-stabilization of distillate fuel that depends on the various blending streams of middle distillates in the introduction part. In the second section the author elaborate the methods so far used to determine the instability of middle distillate fuels. The third section serves the elaborated mechanism of degradation, the role of chemical composition of distillate fuels, and the responsible components in distillate fuels that impart in degradation of distillate fuels. The fourth section comprises the composition of material formed during degradation and the fifth section of reveals the current status of methods used to improve the stability. In combination, these five sections would provide a ready reference source of data available in the literature on diesel fuel stability.

Influence of methanol extraction on the stability of middle distillate fuels

Abstract The stability of six middle distillate fuel samples before and after extraction with methanol under conditions of accelerated ageing were determined. Extraction reduced the tendency of the fuels to form insolubles. The effect was more pronounced for catalytically cracked light cycle oil.

Wax Content of Crude Oil: A Function of Kinematic Viscosity and Pour Point

Precipitated wax has pronounced effect on kinematic viscosity and pour point of crude oils. Thus, the authors attempted to develop a regression model to predict wax content of the crude oil from the kinematic viscosity and pour point data of crude oil. The wax content predicted by this model is in good agreement with those determined by standard acetone method. This model has the standard error of estimate of 1.28 and R2 of 0.92. This model had been compared with other existing models and we found this model was better.

Characterization and Identification of Polycyclic Aromatic Hydrocarbons in Diesel Particulate Matter

Emission of toxic exhaust from diesel engines is one of the major problems associated with the use of petroleum fuels. Particulate matter emission is perceived as a major pollutant, detrimental to the human health and environment, and has led to considerable study. Vehicular emissions comprise toxic pollutants that include unburnt hydrocarbons, polycyclic aromatic hydrocarbons, dioxins, and others. In this study, experiments have been carried out with the objective of determining overall particulate matter chemical composition and size. Electron microscopic images of the emitted soot were studied for average particle size distribution. More than 50 percent of the particles were in the range of 25 to 35 nanometers. Approximately 7, 9, 16, and 5 percent of the measured particles were from 35 to 40, 40 to 45, 45 to 50, and 50 to 55 nanometers, respectively. Determined elements were Al, Ba, Ca, K, Mg, Ti, Zn, and Zr at concentrations of 727, 53, 1100, 701, 1145, 638, 177, and 800 micrograms per milliliter respectively. Fifteen polycyclic aromatic hydrocarbons were detected in the extracts of filters and their concentrations were estimated. This investigation allows the comparison of particulate matter from different fuels and their blends.

Blending complexity of bio-oils

Blending of the original bio-oil and conventional oil is not possible due to the presence of oxygenating polar compounds in the bio-oil. An attempt has been made to remove/reduce the oxygenated compounds from the bio-oil to make a perfect emulsion of bio-oil and conventional oil. In this regard; a technique, i.e. true boiling point (TBP) distillation has been adopted by which the blending complexity of the bio-oil is resolved. In this process, An initial boiling point (IBP) <140°C fraction of the bio-oil has been made, as a result, oxygenate compounds have been removed/reduced from the bio-oil. In addition to this; an indicative emulsion of 10% (v/v) and an IBP <140°C fraction of the bio-oil and conventional diesel have been studied.

Studies on Volatile Characteristics of Middle Distillates and Their Interdependency

Abstract Standard test methods such as those published in American Society for Testing and Materials (ASTM)/Institute of Petroleum/Universal Oil Product are often used to characterize the fuels properties. However, these chemical/physical characterization methods are not only expensive and protracted but also require a large quantity of samples. Every flammable liquid has vapor pressure, which is a function of its boiling point. The distillation and flash point are volatility-dependent characteristics; therefore, these properties are temperature dependent. Most researchers have derived the correlation of flash point with boiling point and vapor pressure for pure organic compounds. The present study proposes a user-friendly empirical model with a correlation technique to predict flash point using ASTM distillation data of middle distillates. In this study, 47 middle distillate samples were taken to predict the flash point with 5 and 10% volume recovery temperature of ASTM D-86 and volume average boiling point (VABP) separately. It was observed that the most appropriate prediction of flash point was with 5% recovery temperature of ASTM D-86 with an R2 0.997. This correlation model was compared with different models and found to be comparatively better and user friendly.

Stabilization Studies of Middle Distillate Fuels: Structural Composition of Insoluble by FTIR Spectroscopy

Abstract For reducing the supply-demand gap of diesel fuel, blending of cracked stocks is essential with straight run products. This enhances the instability problem. This problem can be reduced using various stabilization procedures. In the present paper blends of cracked stocks light cycle oil (LCO) with straight run gas oil (SRGO) were stabilized by methanol extraction and hydrostabilization techniques. The insoluble from these fuels as such and their blends were stabilized and characterized using FTIR spectroscopy.