Process for the preparation of an intermediate pitch for manufacturing carbon products

A process for the preparation of a hydrogenated pitch for manufacturing a mesophase pitch for preparing carbon fibers which comprises heating a heavy oil having quinoline insoluble fraction content of less than 5 wt % selected from the group consisting of coal tars, coal tar pitches, tar by-products from naphtha cracking, tar by-products from gas oil cracking and decant oils in a tubular heater under a pressure of 4 to 50 Kg/cm.sup.2.G at a temperature of 400.degree. to 520.degree. C. with a residence time of 30 to 1000 seconds;

• transferring the heater effluent to a flash distillation column and conducting a flash distillation under a pressure of 0.3 to 1.5 Kg/cm.sup.2.A at a temperature of 430.degree. to 500.degree. C. so as to separate lighter fractions as the overhead of said column from a heavy fraction;
• recovering said heavy fraction from the bottom of said column as an almost isotropic and substantially homogeneous intermediate pitch having a benzene insoluble fraction content of more than 50 wt %, a quinoline insoluble fraction content of less than 30 wt %, and a beta-resins content of more than 40 wt %, hydrogenating said intermediate pitch by using at least one compound selected from the group consisting of tetrahydroquinoline, hydrogenated naphthalene oil, hydrogenated anthracene oil, hydrogenated creosote oil and hydrogenated absorbing oil as a hydrogenating agent and a solvent, in an amount of 1 to 3 parts per 1 part of said intermediate pitch at a temperature of 380.degree. to 480.degree. C., under a presure of 20 to 50 Kg/cm.sup.2.G for 10 minutes to 5 hours and removing said hydrogenating agent and lighter fractions formed during the hydrogenation reaction.