Effective Demetalization and Suppression of Coke Formation Using Supercritical Water Technology for Heavy Oil Upgrading

Abstract

In this study, a new upgrading method with supercritical water was developed for heavy oil in order to produce light oil that was free from heavy metal and heavy hydrocarbon fraction under coke suppression condition. Heating experiments of the heavy oil with and without supercritical water were conducted to gain insights into temporal variation of gas, maltene, asphaltene, and coke yield and existence state of heavy metal vanadium in the heavy oil. The experiments were carried out by an autoclave apparatus with and without continuous supply of supercritical water at 25 MPa and from 400 to 470℃. Results of the experiments showed that gas and reformed oil that composed of maltene was selectively extracted by supercritical water and its extraction rate was increased proportional to temperature. It was valid for suppressing coke formation to heat the heavy oil within coke induction period. The vanadium should be enriched into heavy fraction, because concentration of vanadium in residual oil was proportional to asphaltene concentration. Based on these experimental results, a new upgrading method that works out without detriment to extraction rate of gas and reformed oil under coke suppressing condition was designed. This method was followed by heating the heavy oil at 450℃ within coke induction period and extraction of gas and reformed oil at 400℃ by supercritical water. We have confirmed that this upgrading method enabled us to depress the coke yield 1/70 fewer than 450℃ on extraction rate at 450℃.

Co-pyrolysis of heavy oil and low density polyethylene in the presence of supercritical water: The suppression of coke formation

“…Both co-pyrolysis and pyrolysis were performed at a fixed temperature of 693 K and a water density of 0.30 g/cm 3 .…”

“…Oil refining technologies available, such as catalytic cracking and hydrocracking, have already shown limitation to the processing of heavy oil of inferior quality. Because of the unique solubility and diffusivity properties of hydrocarbons in supercritical water (SCW, T c = 647 K, P c = 22.1 MPa, ρ c = 0.32 g/cm 3 ), the upgrading of heavy oil via pyrolysis in SCW has been extensively investigated in academia since the 1990s [1][2][3][4][5].…”

Pyrolysis of heavy oil in the presence of supercritical water: The reaction kinetics in different phases

“…Since the 1990s, the pyrolysis and the hydrocracking of heavy oil in the presence of supercritical water (SCW, T c 5 647 K, P c 5 22.1 MPa), an environmentally benign solvent for organic reactions, have been attracting increasing attention in academia. [1][2][3][4][5][6][7][8] It was believed that the unique solubility and diffusivity of organics in SCW might have a positive influence on the upgrading of heavy oil in the SCW medium.…”

Synthesis and Mechanism of a Novel Organosilicone Used as a Selective Plugging Agent

“…However, all of them exhibited have the shortages, such as less-thanideal selectivity, high cost, and so on, which greatly limit their application. So, it is pressing and inevitable to develop a novel selective blocking agent with excellent selectivity, low cost and wide raw material sources [9][10][11].…”