Abstract: The disclosure relates to methods to estimate the carbon number of an alkyl substituent (number of carbon atoms in the alkyl substituent) of an aromatic compound using a gel permeation chromatography (GPC) retention time and prediction models.

Abstract: A surface-modified activated carbon includes activated carbon, a plurality of sulfonate groups, and a plurality of metal atoms. The sulfonate groups are chemically bonded to the activated carbon, and the metal atoms are independently chemically bonded to the sulfonate groups. The surface-modified activated carbon has a net positive charge. A method for producing a surface-modified activated carbon includes mixing activated carbon with a sulfur-containing compound including sulfonate groups, chemically bonding the sulfonate groups the activated carbon to produce sulfonated activated carbon, combining the sulfonated activated carbon with a solution containing metal atoms, and chemically bonding the metal atoms to the sulfonate group.

Abstract: A system and a method are provided for calculating the cetane number, pour point, cloud point, aniline point, and/or octane number of a crude oil and its fractions from the density and gel permeation chromatography data of a sample of the crude oil.

Abstract: Disclosed are methods and systems for quantitation of benzene, toluene, ethyl benzene, o-xylene, m-xylene, and p-xylene. High-performance liquid chromatography using a carbon stationary phase and a gradient mobile phase is performed. The carbon stationary phase can be a porous graphitic carbon stationary phase. The mobile phase includes an organic acid in water and an alcohol. The organic acid can include formic acid, and the alcohol can include methanol. The methods and systems achieve a resolution between xylene isomer peaks of greater than 2.0.

Abstract: Disclosed are methods and systems for quantitation of benzene, toluene, ethyl benzene, o-xylene, m-xylene, and p-xylene in aromatics recovery complexes. High-performance liquid chromatography using a carbon stationary phase and a gradient mobile phase is performed. The carbon stationary phase can be a porous graphitic carbon stationary phase. The mobile phase includes an organic acid in water and an alcohol. The organic acid can include formic acid, and the alcohol can include methanol. The methods and systems achieve a resolution between xylene isomer peaks of greater than 2.0 when sampling industrial process streams in aromatic recovery complexes.

Abstract: A method and a system for predicting a molecular weight of a hydrocarbon fluid are provided. An exemplary method includes measuring a density of the hydrocarbon fluid, obtaining an alternative measurement of a physical property of the hydrocarbon fluid, calculating an index value for the hydrocarbon fluid from the alternative measurement, and calculating a predicted molecular weight using an equation that combines the density with the index value. The predicted molecular weight is provided as an output.

Abstract: A system and a method are provided for calculating the cetane number, pour point, cloud point, aniline point, and/or octane number of a crude oil and its fractions from the density and gel permeation chromatography data of a sample of the crude oil.

Abstract: A system and a method are provided for calculating one or more indicative properties, e.g., one or more of the cetane number, octane number, pour point, cloud point and aniline point of oil fractions, from the density and high pressure liquid chromatography (HPLC) data of a sample of the crude oil.

Abstract: A system and a method are provided for calculating one or more indicative properties, e.g., one or more of the cetane number, octane number, pour point, cloud point and aniline point of oil fractions, from the density and high pressure liquid chromatography (HPLC) data of a sample of the crude oil.

Abstract: A system and a method are provided for calculating the cetane number, octane number, pour point, cloud point and aniline point of a crude oil fractions from the density and high pressure liquid chromatography (HPLC) of a sample of the crude oil.