Apparatus for regeneration of cracking catalyst

Abstract

Abstract A catalyst regenerator is disclosed which incorporates a closed vessel having a centered stand pipe concentrically arranged within a spent catalyst distributor. The catalyst is carried upwardly by the distributor and is scattered evenly and concentrically about the distributor. The spent catalyst is deposited on or near the top of the dense phase catalyst bed. A symmetrically arranged, preferably triangular fresh air distributor system including a number of transverse branches having small nozzles mounted thereon forms a grid pattern below the lower portions of the catalyst bed in the regenerator. Air for burning of the coke on the spent catalyst is introduced evenly to minimize the size of the air bubbles in the dense bed. The catalyst in the lower portions of the bed has a minimum of coke remaining thereon. The oxygen of the air which is introduced in the lower portions of the bed is consumed by combustion of the reduced quantity of coke in the lower portions of the bed. As the air flows through the dense bed to the upper surface, the catalyst encountered at the higher levels has more coke on it. However, the air is partly depleted of oxygen which prevents formation of excessive particle temperatures in the dense phase fluid bed. The region of high coke concentration experiences controlled burning achieved by controlled partial oxygen depletion. This tends to burn more of the carbon in the bed, thereby reducing afterburning in the dilute phase above the bed. This provides uniform heating of the catalyst to a higher temperature, thereby reducing the heat required in the feed stock pre-heater. Carbon monoxide disposal equipment is also eliminated by consumption of most of the carbon monoxide within the bed, all without afterburning thereabove.

Inventors

• 👤 James R. Murphy
• 👤 Alvaro A. Murcia

Bibliographic Details