Mohammad Farhat Ali

Studies on the aging behavior of the Arabian asphalts

In this study the rheological, physical, and chemical properties of asphalts procured from Ras Tanura, Riyadh, Kuwait, and Bahrain refineries were evaluated. The rolling thin-film oven (RTFO), termed as short-term aging, and the pressurized aging vessel (PAV), termed as long-term aging, tests were used to simulate asphalt aging. Viscosity, penetration, softening point, and weight loss tests were applied to investigate the rheological properties of fresh and aged Arabian asphalts. The Corbett method was used to separate asphalts into asphaltene, polar aromatic, naphthene aromatic, and saturate fractions. Asphaltene contents and Gaestel index (Ic) were found to increase linearly with aging process. It was found that PAV has more severe effects on the rheological and chemical properties of asphalt than RTFO test method. Using infrared spectroscopy, it was found that on aging the weight percent of oxygen as carbonyl and sulfur as sulfoxide group types increased in asphaltenes. Significant differences were observed between the structure and composition of fresh and aged asphaltenes of Ras Tanura (RT) asphalt.

Use of X-ray diffraction in assessing the aging pattern of asphalt fractions

The X-ray diffraction (XRD) method was employed to investigate and compare some of the crystallite parameters and aromaticity of asphaltenes obtained from fresh and aged Arabian asphalts, procured from Ras Tanura (RT) and Kuwait (KW) refineries. A few crystallite parameters in the polar aromatics, naphthene aromatics and saturate fractions of these Arabian asphalts were also determined. The results obtained by XRD method for both the types of asphaltenes and other fractions were evaluated and compared. Significant differences were observed between the structure and the aging patterns of fresh and aged asphaltenes of RT and KW asphalt. The results indicate that the source and chemistry of asphalt are responsible for the aging behavior of its components. The rolling thin-film oven and the pressurized aging vessel tests were used to simulate asphalt aging in this research.

The role of asphaltenes, resins and other solids in the stabilization of water in oil emulsions and its effects on oil production in Saudi oil fields

Abstract The factors contributing to the stability of water-in-oil (w/o) emulsions is a problem of great concern and economic importance to the oil companies in the production of oil from underground reservoirs. This paper reports the results of a laboratory investigation into various factors affecting the stability of w/o emulsions in some crude oil samples obtained from well heads of different oil fields in the Eastern Province of Saudi Arabia. A pressure sampling technique was used to collect the upstream samples from well heads. The emulsion samples were collected both from problem (tight emulsions) and non-problem (loose emulsions) wells. Solids present in the produced fluids were separated by successive toluene dilution and were analyzed for their composition using various methods such as XRD, TGA, and DSC. These data indicate that these solids consist of calcite, wax, asphaltene and resins. The oily parts of the samples were separated into asphaltenes, resins and maltenes. The asphaltene fraction is found to play an important role in the stabilization of w/o emulsions. Asphaltene adsorbs on mineral and wax particles, thus contributing significantly to emulsion stability.

Investigation of chemical transformations by NMR and GPC during the laboratory aging of Arabian asphalt

In this work, the chemical properties of a commercial grade Saudi Arabian asphalt procured from Ras Tanura refinery were evaluated. The rolling thin film oven (RTFO), termed as short-term aging, and pressurized aging vessel (PAV), termed as long-term aging, tests were used to simulate the laboratory aging of this asphalt. It was found that PAV has more severe effects on the chemical properties of asphalt than RTFO method. The Corbett fractionation procedure was used to separate fresh and aged asphalts into four generic fractions namely; asphaltenes, polar aromatics, naphthene aromatics, and saturates and various analytical techniques were applied to evaluate the chemical changes that occurred during the aging processes. High pressure-gel permeation chromatography (HP-GPC) molecular weight and size distributions suggested that molecular rearrangement occurs predominantly on aging. Carbon and proton NMR measurements of generic fractions showed that isomerization, internal cross-linking, and dehydrogenation were the main chemical reactions of hydrocarbon groups following aging. Coupling the results from the GPC and NMR techniques have led to some interesting information concerning the chemical reaction types during the aging processes. Significant differences were observed between the structure and composition of fresh and aged generic fractions of Ras Tanura asphalt.

THERMAL DECOMPOSITION OF SAUDI CRUDE OIL ASPHALTENES

Abstract Asphaltenes precipitated by the use of pentane, heptane and decane solvents from Saudi Arabian Light (AL) and Saudi Arabian Heavy (AH) crude oils 370°C + residua have been investigated by thermal gravimetric analysis and pyrolysis - gas chromatographic analysis at 350°C and 520°C. Gas chromatographic analysis of the gases evolved during pyrolysis has shown that CO, CO2 and CH4 constitute the major portion of the gases evolved at 350°C from pentane and heptane asphaltenes of AH residue and from pentane asphaltenes of AL residue. Whereas gases evolved from decane asphaltenes are dominated by CO2 and C2-C4 hydrocarbon gases. At 520°C, hydrogen and methane represent 56-80 vol %of the gases evolved from all the four asphaltenes. The amounts of C1-C4 hydrocarbon gases increased with an increase in the carbon number of the precipitating solvent at 350°C and decreased at 520°C. The presence of up to C36 normal alkane hydrocarbon has been indicated in the maltenes produced from these asphaltenes. The loss...

Structural Studies on Residual Fuel Oil Asphaltenes by RICO Method

Abstract Structural characterization of asphaltenes isolated from Saudi Arabian heavy and medium crude oils was undertaken by using ruthenium ion catalyzed oxidation (RICO) method. The RICO method was capable to convert aromatic carbons selectively into carbon dioxide and carboxylic acids and esters group while leaving aliphatic and naphthenic structures of asphaltenes essentially unaffected. Detailed analyses of RICO products of both Arab heavy and Arab medium asphaltenes were conducted using FT-IR, 13C-NMR, IC, GPC, and GC-MS techniques. These analyses indicate that the aqueous phase fraction (water-soluble products) obtained from RICO reaction of asphaltenes consists of aliphatic dicarboxylic acids and aromatic poly carboxylic acids with longer alkyl chains. The 13C-NMR and GC-MS analyses of organic phase products of asphaltenes indicate that this fraction contains large amount of aliphatic carboxylic acids with longer alkyl groups. The oxidation products of both Arab heavy and Arab medium asphaltenes were found to be dominated by a homologous series of straight chain monocarboxylic acids suggesting that the normal alkyl chains are major and important constituents of the chemical structure of both asphaltenes.

ASPHALTENES IN SAUDI ARABIAN HEAVY CRUDE OIL SOLUBILITY AND MOLECULAR WEIGHTS IN HYDROCARBON SOLVENTS

ABSTRACT The asphaltenes from Saudi Arabian Heavy crude oil residue ( 370°C+ ) were precipitated by adding n-alkane solvents ( n−C5 to n−C 10 ) to the crude oil / residue.

Techno-economic evaluation of waste lube oil rerefining

Abstract This paper discusses the secondary use of used automotive lubricating oils. Current technologies for processing waste lube oil into new lubricants is outlined and the performance features of these products are compared with that of virgin materials. Process technology of Meinken and Mohawk were selected for techno-economic evaluation. A plant size of 50 000 TPA waste oil re-refining was considered for economic study of these processes. The estimated production cost for Meinken process was found to be

Catalytic Processing of Waste Plastics With/Without Petroleum Resid—An Economic Evaluation

348.8 per ton and for Mohawk process, assuming hydrogen supply to be made available from adjacent refinery, it was estimated to be

CENTRAL SAUDI ARABIAN CRUDE OILS: A GEOCHEMICAL INVESTIGATION

198.4 per ton. Meinken process appears to be more popular but profitability was found to be lower than Mohawk. Mohawk process is limited due to location factor which requires hydrogen from an adjacent petrochemical plant.