| 摘要 |
PURPOSE:To accomplish stable distillation of coal-liquefied oil for a long period with preventing distillation column from corrosion, by forming, with oxidation- treated titanium, specific temperature zone of the inner wall of said column in coal liquefaction unit and by performing distillation so that said zone represents a specific range of temperatures. CONSTITUTION:Such a zone of the inner wall of distillation column in a coal liquefaction unit as to fall between 220 deg.C and 280 deg.C in the temperature at least during distilling operation is formed by coating a film obtained by oxidation treatment of Ti (alloy) in an atmosphere containing oxygen. Next, coal-liquefied oil is distilled in such a manner that said zone falls between 220 deg.C and 280 deg.C in the temperature. Said oxidation treatment is preferably carried out by heating titanium at 200-900 deg.C for 2-120min in the atmosphere. From an economical point of view, it is recommended that only said zone and its vicinity be coated with the film mentioned above.
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