It was about 30 years ago when I invented a new process to obtain phenols, or oxygen compounds, from man-made petroleum (made by coal hydrogenation) containing phenols by super heated water extraction. I obtained a Japanese patent on this invention and made it known to the public. Observing the similarity between the nature of oxygen and that of sulfur in their respective compounds, I took aim at the possibility of desulfurizing petroleum by super heated water extraction. I, then, arranged preliminary experiments. In an autoclave at 300°C, 40‰ desulfurization of heavy oil was proved ex-perimentally.
Based on my old experience, I had once expected that I would obtain even a higher efficiency for this desulfurization if I would use a counter-current extraction system. I made experiments with a simple made-shift apparatus. However, due to a deficient feeding device of counter-current the experiment did not effect expected results, the efficiency of which was only 30‰ desulfurization of light oil (vacuum distilled) at 230°C.
Though the experiment did not end up to my satisfaction, I obtained from it con-ditions necessary for the industrialization of desulfurization of mineral oils. I am also convinced now, that the desulfurization of mineral oils will be easily realized by means of super heated water extraction, if I had necessary apparatus with perfect feedding system of counter-current. Furthermore, I am also certain that a new field will be developed where organosulfur compounds obtained by said extraction method will find various useful applications.
