| 摘要 |
Upgrading of a high-boiling hydrocarbon feed to produce lower-boiling materials is effected by catalytic hydrogenation in a series of at least two ebullated-bed zones. The improvement comprises (a) recovering from the effluent a recycle stream which has a 5 vol.% distn. temp. of at least 232 (esp. at least 316)deg. C and contains at least 25 vol.% of material boiling above 510 deg.C; (b) contacting the recycle stream with a solid adsorbent having a specific surface of 1-200 (pref. 1-5) square m/g; and (c) passing the recycle stream to at least the last hydrogenation zone. The process can be applied to petroleum residua, heavy crudes, solvent-refined coal, etc. Step (b) removes coke precursors from the recycle stream, so that the process can be operated at higher conversion without excessive build-up of coke on the catalyst. |
