Manufacture of graphitizable petroleum coke

摘要

In a process for producing a coke which when calcined and graphitized has a longitudinal coefficient of thermal expansion per DEG C. not substantially above 0.55 X 10-6 the charge stock which is subjected to coking conditions of temperature and pressure consists of 68-90% by weight of a tar containing a large proportion of aromatic hydrocarbons and 10-32% by weight of a heavy liquid refinery residue. Preferably the charge stock contains 75-85% by weight of the tar and 15-25% by weight of the refinery residue. The tar containing the large proportion of aromatic hydrocarbons is produced by thermally cracking a charge stock consisting of the residues from catalytic cracking or coking processes, gas oils produced by thermal or catalytic cracking or coking processes or other high boiling products of high temperature processes. The heavy liquid refinery residue may comprise one or more of a Virginian reduced crude, a Duo-Sol extract, a furfural extract or hydroformer bottoms. The coke producing charge stock is coked in a vertical drum for a period of several hours at a pressure of about 65 p.s.i.g. and a temperature between 830 DEG and 900 DEG F., the contents of the drum being stirred vigorously in one direction during the coking period. The coke thus produced is calcined at between 1800 DEG -3600 DEG F., and finally graphitized at between 4500 DEG -5500 DEG F.