| 摘要 |
An improved process for catalytic desulfurization of petroleum residua feedstocks to provide at least about 75% desulfurization of the liquid product while achieving low catalyst deactivation and increased catalyst age. In the process which uses an ebullated catalyst bed reactor, the reaction conditions are usually maintained at 790 DEG -860 DEG F. temperature, 1000-1800 psig hydrogen partial pressure, and 0.2-2.0 Vf/hr/Vr space velocity. To control carbon and metals deposition on the catalyst, used catalyst is withdrawn from the reactor, a minor portion of the catalyst is discarded to control metals deposition and maintain catalyst activity, and the remaining catalyst is regenerated to remove carbon by carbon burnoff and returned to the reactor for further use. If desired, the regenerated catalyst can be presulfided before returning it to the reactor. Following phase separation and distillation steps, the desulfurized hydrocarbon liquid products are withdrawn from the process. For feedstocks requiring higher desulfurization, two stages of catalytic reaction are provided in which the used catalyst is withdrawn from each stage reactor and regenerated to remove carbon and then returned to the same stage reactor. Alternatively, fresh catalyst is added to the second stage only, some used catalyst from the second stage reactor is transferred to the first stage reactor, and used catalyst is discarded from the first stage reactor.
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