| 摘要 |
The disclosed method and apparatus provides for providing piecewise continuous addition of microspheroidal ("MS") Fluid Catalytic Cracking ("FCC") catalyst additives and/or bulk catalyst to an in situ circulating, active catalyst inventory of a fluid catalytic cracking unit at programmed rates precisely controlled to sustain effective additive concentration while damping excessive performance fluctuations. In a preferred version of this invention, each of a series of such apparatus comprising one such device for each catalyst additive, is operated on a basic cycle time length during a portion of which the unit is engaged in active addition while in the remainder of the time it is passive, and wherein the timing being under the primary control of a process variable feedback signal. An overriding secondary control, imposed by a fundamental performance criterion, may also be employed.
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