APPLICATION OF CHROMATOGRAPHY IN PETROLEUM FIELD

Modern chromatography by virtue offantastic capabilities for separation, qharacterization, quantitation and fractionation has emerged as a potential analytical technique for hydrocarbon industry. Presently the gas chromatography alongwith high performance liquid chromatography coverwide range ofapplications in diversified areas including Basic and applied research. Availability of large number of stationary phases, specific detectors, newer analytical procedures, improved instrumentation alongwith hyphenated techniques have made chromatography an indispensable and versatile tool. This paper deals with the recent trends in chromatography for the analysis of various petroleum fractions, right from light gases to higher boiling fractions using gas chromatography (GC),high performance liquid chromatography (Hplc)and supercritical fluid chromatography (SFC

Maltenes and Asphaltenes of Petroleum Vacuum Residues: Physico-Chemical Characterization

Solvent separation is frequently applied to petroleum vacuum residues to reduce the coke-forming tendencies of these materials. This process is capable of removing all or a substantial amount of asphaltenes from feedstocks that are destined for further processing and thus applied as the first step of refining. Maltenes and asphaltenes obtained from vacuum residues of Heera (HVR) and Jodhpur (JVR) Indian crude oils using n-hexane, n-heptane, and soluble and insoluble fractions obtained using ethyl acetate, were characterized for elemental analysis, molecular weight, conradson carbon residue (CCR), specific gravity, and pour points. The resulting degree of removal of asphaltenes ranged from 10–28 wt% of the HVR and 25–50 wt% of the JVR. The increasing trend of the American Petroleum Institute (API) gravity and the decreasing trend of CCR and pour point are observed with the increase in removal of asphaltenes. Keywords: asphaltenes, elemental analysis, maltenes, petroleum, vacuum residu

Characterization of Petroleum Heavy Distillates Using HPLC and Spectroscopic Methods

Petroleum heavy distillates find wide application as feedstocks for upgradation through secondary conversion processes. Compositional data on such feedstocks provide useful information to the refiners for selecting processing parameters to achieve product selectivity, quality, and yield. A HPLC method has been optimized to estimate hydrocarbon group types in five lubricating oil base stocks using refractive index (RI) and UV detectors. Data generated at two wavelengths (210 and 254 nm) indicated best results for monoaromatics at 210 nm due to enhanced response and compared well with mass spectrometry data. RI data revealed that saturate content decreases from spindle oil (56%) to heavy oil (42%) which is corroborated by MS data measured for three samples. NMR data exhibited that light oil is more paraffinic (63%) in nature as indicated by branchiness index (0.478). UV data revealed an increasing trend of monoaromatics from spindle (16%) to deasphalted oil (DAO) (20%) and this is supported by MS data, while DAO and heavy oil indicated higher values of diaromatics

Lipid and Fatty Acid Biosynthesis by Rhodotorula minuta

Demand for fatty acids is increasing at an annual rate of 17%, due to their increased use in the oleochemical and transport industries. Presently, vegetable oils are the major source of fatty acids, whereas lipids with fatty acids similar to those of some vegetable oils have been reported to be synthesized by oleaginous microorganisms. In the present study, the culturing conditions for the oleaginous yeast Rhodotorula minuta IIP-33 have been optimized. In contrast to the lipid accumulation characteristics of most oleaginous yeasts, a carbonto- nitrogen ratio of 30 was favorable for maximal accumulation of lipids (48%) with 22.5% conversion of glucose as carbon substrate. The lipids contained fatty acids in the C7–C18 range, the relative composition of which varied with culture temperature. JAOCS 75, 501–505 (1998)

Structural Characterization of Asphaltenes and Ethyl Acetate Insoluble Fractions of Petroleum Vacuum Residues

Asphaltenes and insoluble fractions of vacuum residues (VRs) of two Indian crude oils (viz. Heera and Jodhpur) of different specific gravity were obtained by precipitation of VRs in n-hexane, n-heptane, and ethyl acetate, and also by subsequent reprecipitation of n-heptane and ethyl acetate soluble fractions by n-pentane. The effect of various solvents on average molecular structure of asphaltenes and insolubles was studied using nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR), and size exclusion chromatography (SEC). The asphaltenes and insolubles of Jodhpur VR have higher amounts of high molecular weight species with a high concentration of condensed and substituted aromatic rings, branched and/or short alkyl side chains, oxygen and nitrogen functionalities, compared to that of Heera VR. Ethyl acetate insolubles comprise a higher number of substituted aromatic structures, branched aliphatic structures, complex average unit structures, nitrogen and oxygen functionalities, and high molecular weight (MW) species as compared to hexane and heptane asphaltenes. Heptane insolubles consist of more naphthenic rings condensed with aromatic rings than C6A and EAI. Keywords: asphaltenes, FTIR, insolubles, NMR, petroleum, SEC, vacuum residu

Hydrocarbon group type analysis of petroleum heavy fractions using the TLC-FID technique

Hydrocarbon group type analysis is important in all conversion processes and in preparation of feed for these conversion processes so as to learn the selectivity of the different type of catalysts for product yield and quality. The use of the Mark 5 Iatroscan detector and the method reported here allowed for a rapid and quantitative hydrocarbon group type analysis of petroleum residues without prior separation of asphaltenes. SARA type analyses of petroleum residues have been performed by a three stage development using n-hexane, toluene and DCM (95%):MeOH (5%). The standard deviation and coefficient of variation in repeated measurements by this method were as low as 0.65 wt% or less and 3.5 wt% or less, respectively. The time required for analysis of 10 samples could be as short as 90 min

The Causal Relationship Between Economic Policy Uncertainty and Stock Returns in China and India: Evidence from a Bootstrap Rolling Window Approach

This article applies a bootstrap rolling-window causality test to assess the causal relationship between economic policy uncertainty (EPU) and stock returns in China and India. Empirical literature examining causality between two time series may suffer from inaccurate results when the underlying full-sample time series have structural changes. However, the bootstrap rolling-window approach enables us to identify possible time-varying causalities between time series based on sub-sample data. Using a twenty-four-months rolling window over the period 1995:02 to 2013:02 in China and 2003:02–2013:02 in India, we do find that there are bidirectional causal relationships between EPU and stock returns in several sub-periods rather than in the whole sample period. However, the association between EPU and stock returns is, in general, weak for these two emerging countries. Our findings have important implications for policy makers and investors.http://www.tandfonline.com/loi/mree202017-09-30hb2016Economic

Genetic basis of PD-L1 overexpression in diffuse large B-cell lymphomas

MTG4Molecular tumour pathology - and tumour genetic