| 摘要 |
A multiple stage catalytic conversion system in which a hydrocarbonaceous charge stock and hydrogen flow serially through a plurality of catalytic reaction zones, in each of which the catalyst particles are downwardly movable via gravity flow. At least four reaction zones are utilized, with the fresh feed and hydrogen reactant stream being split between the first and second reaction zones. The flow of that portion introduced into the second zone is restricted. The effluent stream from the first reaction zone is also restricted and then combined with the effluent from the second reaction zone. One portion of the combined effluent streams is introduced into the third reaction zone, and the remaining portion is restricted in flow, combined with the effluent stream from said third reaction zone, and introduced into the fourth reaction zone. This technique decreases the mass flow to the first three zones and increases the pressure drop experienced within the entire conversion system, thus serving to alleviate the problems associated with the occurrence of stagnant catalyst areas as a result of catalyst particles being "pinned" within a reaction zone and thus unable to assume a downward, gravity flow pattern. Restriction of the second zone feed and first reaction zone effluent insures a higher pressure in the first zone. |
