| 摘要 |
Polynuclear aromatic compounds obtained from petroleum residua and coal liquids and containing three to six aromatic ring compounds are first catalytically hydrogenated and then hydrocracked, either thermally or catalytically, to produce high yields of two-ring and mononuclear aromatic products. Useful hydrogenation reaction conditions are 149-482 DEG C (300-900 DEG F) temperature, and 69-124 bar gauge (1000-1800 psig) hydrogen partial pressure. The hydrogenation catalyst used can be nickel-tungsten on a silica-alumina support. The hydrogenated material is then hydrocracked at conditions of 427-704 DEG C (800-1300 DEG F) temperature, and 34-207 bar gauge (500-3000 psig) hydrogen partial pressure. The hydrocracking step may use a catalyst comprising cobalt- molybdenum on alumina and a space velocity of 3-7 gm/hr/gm catalyst. A preferred feedstock is steam-cracker pyrolysis tar such as produced from steam cracking of ethylene. |
