The feasibility studies for desulfurization of heavy oil by intermetallic adsorption and ultrasonic oxidation.

摘要

Petroleum industry will inevitably utilize high-sulfur content heavy oil due to the worldwide depletion of conventional crude oil. Sulfur removal from heavy oil has been a tremendous burden on modern oil refinery. Technologies for crude oil desulfurization to-date, which include methods such as hydrodesulfurization (HDS), consume huge amount of energy due to required high temperature and high pressure. The poisoned and exhausted catalyst beds need frequent change. High demand of hydrogen gas also poses risks to facilities and personnel. As stringent clean air regulations are imposed on fuel emissions, any contribution to remove sulfur from petroleum products will help the environment and save the limited energy resource globally.; Very little research work is known on desulfurization directly from crude oil based upon an upstream refinery point of view. The present study of desulfurization from high-sulfur heavy oil proposes two different methods. Both of them are innovative methods and the most important fact is that they can be conducted under environmentally mild conditions. The first one is intermetallic adsorption. Based upon the principle of the unique properties of intermetallic crystalline powder made of tin and antimony and the membrane mimetic chemistry, the impurities, including sulfur species in heavy oil, can be adsorbed onto the available defect sites on the surface of intermetallics. Sulfur compounds are then removed by destructive adsorption. The second method is ultrasonic oxidation process. The phenomenal implosion of cavitation bubbles induced by acoustic wave energy creates localized extreme temperature and pressure. Thermal decomposition and free radical chain reactions may thus occur. Hydroxyl free radical produced through sonolysis has been proved to be an extremely active and strong oxidant. Applying the same principle of membrane mimetic chemistry with hydrogen peroxide assisted ultrasound under oxidative condition, the heavy crude can be significantly desulfurized. The converted sulfone analogs have been identified by using GC/MS coupled with sulfur selective pulse flame photometric detector followed by MS/MS analysis. The efficiency of desulfurization can be further increased to about 80% through the process of sulfur-selective solvation by N,N-dimethylformamide.