Patent ID: 7803326

Claim:
An apparatus for transferring catalyst from a regeneration zone to a reaction zone in a hydrocarbon conversion unit, comprising: a) a transfer vessel for transferring regenerated catalyst from the regeneration zone at a first pressure to the reaction zone at a second pressure wherein the second pressure is greater than the first pressure; b) a first line communicating catalyst to the transfer vessel and coupled to a first valve to allow catalyst into the transfer vessel and a second line communicating catalyst from the transfer vessel and coupled to a second valve to allow catalyst out of the transfer vessel; and c) a third line for allowing the passage of gas therethrough at a pressure higher than the first pressure having a first portion communicating with the transfer vessel and having a second portion coupled to third and fourth valves, wherein each of the third and fourth valves has a first position that is open and a second position that is closed, which corresponds, respectively, to the opening and closing of the first and second valves to allow gas to pass therethrough wherein the first portion of the third line is coupled to the second portion between the third and fourth valves and one end of the second portion communicates with a vent line from a storage vessel.