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High concentrations of fuel-range hydrocarbons may be recovered from heavier alkyl-aromatic compounds in crude oil after supercritical water (SCW) treatment. Arabian Heavy (AH) crude oil was treated in SCW and analyzed using two-dimensional gas chromatography (GC×GC FID). Cracking mechanisms were investigated using the model compound hexylbenzene under similar SCW treatment conditions. The results of the model compound experiments were compared to predictions of a kinetic model built by the Reaction Mechanism Generator (RMG). AH crude cracked significantly during SCW treatment. The GC-observable mass fraction increased by 90%. We conducted studies on the distilled samples of crude oil, and found that significant changes in the composition of the SCW-treated 'heavy' fraction occurred. Significant formation of aliphatic hydrocarbons and small-chain BTX-type compounds were found in the SCW-processed samples. Hexylbenzene conversions differed between the crude oil studies and the model compound studies. It is possible that hexylbenzene (and other alkylbenzene) conversion is hindered by preferential cracking of heavier hydrocarbons in the bulk crude oil solution. The mechanistic model run for the cracking of hydrocarbons in SCW treatments of the model compound hexylbenzene resulted in the major liquid products toluene, styrene and ethylbenzene. The selectivity of ethylbenzene and styrene changed over time. The apparent conversion of styrene into ethyl benzene was possibly via a reverse disproportionation reaction. Ultimately a mechanism was built that serves as a basis for understanding the kinetics of hydrocarbon cracking in SCW. Introduction Supercritical water (SCW) is seen as an attractive upgrading and desulfurization medium for crude oil processing. SCW has unique properties that set it apart as an ideal solvent for organic reactions, including a low dielectric constant, high ion product and high diffusivity [1]. Industry has recently taken an active interest in using water as a reactive solvent, with patents approved for oil and bio-crude oil upgrading [2-5]. This is partly because there is published literature that has demonstrated that heavy hydrocarbons exposed to supercritical water produce significant concentrations of gas and light liquid products[5-8]. It has also been shown that water may enhance the production of benzene, toluene and xylene (BTX) compounds from crude oil in the presence of sulfur [9]. As such, it is conceivable that SCW could be used as a two-in-one unit

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The technology developed in this work takes advantage of the temperature-sensitive dielectric constant of water to micronize hydrophobic compounds. At elevated temperatures subcritical water (SBCW) is a good solvent for nonpolar compounds, while at ordinary temperatures it behaves as an antisolvent. The solubility of the model compound griseofulvin in SBCW was determined at 70 bar and temperatures between 130 and 170 °C. In this work griseofulvin was dissolved in subcritical water. The resulting subcritical solution was then injected into water at room temperature to rapidly quench the temperature and trigger precipitation of the solute. The resulting particle morphology was markedly dependent on operating conditions such as temperature and concentration of the subcritical solution. It was possible to generate microparticles of griseofulvin with controllable morphologies. The process is rapid and does not involve the use of organic solvents.

Two-dimensional gas chromatography with sulfur chemiluminescence detection (GC × GC-SCD) is applied to understand the changes in alkylated thiophenes, benzothiophenes (BTs), and dibenzothiophenes (DBTs) during supercritical water (SCW) upgrading of Arabian Heavy crude oil. It is shown that SCW treatment of heavy crude oil has several important effects: (1) The amount of BTs and DBTs in the distillate range increase, primarily due to cracking of heavier compounds. (2) Most of the long side chains on the thiophenes, BTs, and DBTs crack to form the corresponding thiophenic compounds with shorter side chains. (3) A small amount of the alkylated thiophenes undergo ring closure to form BTs during SCW treatment, and a small amount of the alkylated BTs appear to form DBTs in a similar way. As reported earlier, SCW treatment removes some of the sulfur from the oil phase, presumably as hydrogen sulfide (H2S). Distilling the heavy crude oil into light and heavy fractions and treating these fractions individually with SCW showed these effects more clearly. Model compound studies on hexylthiophenes confirm that SCW cleaves alkyl chains bound to thiophenes.