PURPOSE: To obtain pitch for carbon fiber, by heat-treating heavy oil, etc., free from quinoline-insoluble component, distilling the treated oil, heat-treating the resultant pitch having high softening point, distilling the pitch and heat- treating the obtained hydrogenated pitch having high softening point.
CONSTITUTION: A petroleum-based or coal-based heavy oil or pitch free from quinoline-insoluble component is heat-treated in the 1st continuous tubular furnace preferably under 4W50kg/cm2G pressure at 400W530°C and a retention time of 30W1,000sec optionally in the presence of 0W2 times volume of an aromatic hydrocarbon oil. The heat-treated product is distilled in the 1st distillation column and a pitch having high softening point is obtained from the column bottom. The pitch is subjected to the 2nd-stage heat-treatment in the 2nd continuous tubular furnace in the presence of 1W3 times volume of a hydrogen-donative solvent. The heat-treated product is distilled in the 2nd distillation column and the hydrogenated pitch having high softening point is obtained from the column bottom. The pitch is subjected to the 3rd heat-treatment under the blast of an inert gas or hot vapor of light oil to obtain the objective pitch. The above 1st and 2nd treatements are continuously carried out.
NAITO SAKAE
NAKAJIMA RYOICHI
AGENCY IND SCIENCE TECHN