Removal of Nickel and Vanadium from Heavy Oils Using Supercritical Water

Abstract

Heavy oils require substantial cracking in order to be economically refined to produce usable products. One major problem affecting the economics of refining heavy oils is the metal compounds contained in many of these oils which poison the catalyst used to crack the oil. Demetallization methods include physical, chemical, electrochemical, catalytic and supercritical water (SCW) techniques. Few of these methods are viable and/or efficient for the demetallization of heavy oil. This paper discusses the SCW based demetallization process by reviewing the open literature. The potential benefits of SCW based demetallization of heavy oils are also explored. Water partial pressure (WPP) has a moderate effect on the reaction of metalloporphyrins (MPs) in SCW; but temperature has a remarkably high effect. Metal removal is sensitive to the conversion of MP and increases exponentially with higher conversion. The kinetics are consistent with first-order dependency on MP disappearance. The reaction mechanism can be explained in terms of the free radical mechanism, but additional experiments and analysis are required to understand the fate of the metal after reaction. This non-catalytic SCW based upgrading process has the potential to allow production of refined fuel from heavy oils.

A Review of Laboratory-Scale Research on Upgrading Heavy Oil in Supercritical Water

“…Zhao et al [44,45] reported that the upgrading of heavy oil in SCW could significantly lower the Ni and V content in the upgraded products. Mandal et al [97,[104][105][106] systematically studied the non-catalytic demetalization of three model porphyrinic compounds (nickel-5,10,15,20-tetraphenylporphine, nickel etioporphyrin, and vanadyl etioporphyrin) in SCW. In these experiments, they analyzed the effect of temperature and pressure on the demetalization of porphyrinic compounds.…”

Nickel Tetraphenylporphine Extraction from Model Heavy Oil Using Ionic Liquids

“…It produces vanadium pentoxide when it burns during the combustion process [4,5]. Vanadium pentoxide is a toxic material and is harmful to the environment.…”

Total Acid Number Reduction of Naphthenic Acids Using Supercritical Fluid and Ionic Liquids

“…Moreover, continuous hydrothermal systems ofer the ability to carry out synthesis in a high-throughput mode, enabling the discovery of new materials [75]. Furthermore, SCW can remove heavy metals from metalloporphyrin compounds efectively and eiciently in an environmentally friendly way [76]. Thus, the sc-CO 2 and the SCW have atracted tremendous interest among academia and industry in this modern era as a green process.…”