Patent ID: 7033488

Claim:
A method of decreasing the average equilibrium age of catalyst in a multi-reactor system comprising: placing an amount (X) of a fresh catalyst into a first reactor; placing an amount (Y) of a fresh catalyst into a second reactor; placing an amount (Z) of a fresh catalyst into a third reactor, wherein the third reactor is in parallel with the first reactor; operating the first, second, and third reactors to catalyze first, second, and third respective reactions of reactants to products, wherein the first, second, and third reactions create partially spent catalyst having a substantially uniform age distribution; withdrawing from the first reactor a portion of the partially spent catalyst (xX), wherein x is <1; replacing the portion of the partially spent catalyst withdrawn from the first reactor with a substantially equivalent amount of fresh catalyst; withdrawing from the third reactor a portion of the partially spent catalyst (zZ), wherein z is <1; replacing the portion of the partially spent catalyst withdrawn from the third reactor with a substantially equivalent amount of fresh catalyst; withdrawing from the second reactor a portion of the partially spent catalyst (yY), wherein y is <1 and wherein yY≦(xX+zZ); and replacing the withdrawn partially spent catalyst from the second reactor with a substantially equivalent amount of partially spent catalyst from the portion withdrawn from the first and third reactors.