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A process and apparatus for fluidized bed combustion using a dense phase combustion zone over a dilute phase combustion zone. When used to regenerate FCC catalyst containing coke with relatively large amounts of NOx precursors, the catalyst is added to and partially regenerated in the dense phase zo

A process and apparatus for fluidized bed combustion using a dense phase combustion zone over a dilute phase combustion zone. When used to regenerate FCC catalyst containing coke with relatively large amounts of NOx precursors, the catalyst is added to and partially regenerated in the dense phase zone and then falls down into the dilute phase zone. Most of the combustion air is added to the dilute phase and rises into and fluidizes the dense phase zone. NOx formed in the dilute phase is reduced to N2 in the dense phase.

대표청구항 ▼

A fluidized bed combustion process wherein a combustible substance is burned with an oxygen containing gas at fluidized bed combustion conditions including a flue gas oxygen concentration of 0 to 10% oxygen, to produce a flue gas characterized by countercurrent combustion in: (a) a dilute phase base

A fluidized bed combustion process wherein a combustible substance is burned with an oxygen containing gas at fluidized bed combustion conditions including a flue gas oxygen concentration of 0 to 10% oxygen, to produce a flue gas characterized by countercurrent combustion in: (a) a dilute phase base zone comprising a dilute phase, fluidized bed combustion zone wherein oxygen containing gas is added, said base zone having a top portion and a top cross-sectional area, and operating at dilute phase conditions including a superficial vapor velocity; (b) a dense phase fluidized bed zone wherein said combustible substance is added and wherein combustion occurs comprising a dense phase fluidized bed supported by and in open fluid communication with the dilute phase base zone, and wherein said dense phase fluidized bed zone has an average cross-sectional area and the cross-sectional area of said dilute phase base zone at said top portion is 15 to 90% of the average cross-sectional area of said dense phase fluidized bed zone; and (c) a dilute phase upper zone above said dense phase fluidized bed, characterized by a relatively lower superficial vapor velocity than said dilute phase base zone, from which said flue gas is removed.