Catalytic cracking regeneration process and equipment with low NOx emission

Abstract

The invention discloses a catalytic cracking regeneration process and equipment with low NOx emission, belonging to the field of petrochemical industry. A spent catalyst and air enter a riser generator from the bottom of a regenerator; 20-60% of carbon is burned off in the riser generator; the catalyst and the smoke containing rich CO after reaction enter a multi-stage countercurrent fluidized bed regenerator to continuously react; and the gas containing rich CO and the gas containing rich oxygen are blown into the middle part of the multi-stage countercurrent fluidized bed in a staggered mode, thereby forming multiple layers of reduction regions and oxidation regions. The regeneration equipment provided by the invention comprises the riser regenerator and the multi-stage countercurrent fluidized bed regenerator, wherein the two regenerators are connected in series and arranged in a coaxial or parallel mode; and multiple gas distributors are arranged in the middle part of the multi-stage countercurrent fluidized bed regenerator, thus, the multi-stage countercurrent fluidized bed regenerator becomes a fluidized bed regenerator with a multi-layer and multi-region oxidation and reduction environment. By the invention, the concentration of NOx in catalytic cracking regeneration smoke is reduced below 20ppm, and the carbon content of a regenerant is reduced below 0.05wt%.

Description

technical field [0001] The invention belongs to the technical field of petrochemical industry, in particular to a low NO x Emissions of catalytic cracking regeneration processes and equipment. Background technique [0002] In the fluid catalytic cracking (FCC) process, the feedstock enters a riser cracking reactor and reacts in contact with hot catalyst from the regenerator, converting it into lighter, higher-value products. But at the same time, with the generation of by-product coke, the generated coke covers the catalyst surface and reduces the catalyst activity. The coked catalyst is separated from the hydrocarbon vapor in the separation zone and enters the regenerator for regeneration. [0003] The coked catalyst is in contact with air, and the surface-loaded coke will burn to form CO or CO 2 , the transformation of nitrogen-containing substances in coke mainly forms N 2 and a small amount of NO x . In the past, when people did not have high requirements for the en...

AI Technical Summary

Problems solved by technology

Methods (1) and (2) require expensive capital and operating costs

Method (3) is theoretically economical for NO removal x method, but catalyst additive SO 2 The problems of poisoning and deactivation under oxygen-enriched atmosphere have not been well resolved, thus limiting the wide application of this method

For example, Kellogg Company uses increased baffles to reduce back-mixing and create countercurrent contact conditions with air; the countercurrent regeneration method adopted by UOP Company is helpful for reducing NO x The discharge effect is obvious, but these countercurrent forms only form a single oxidation zone and reduction zone, which cannot meet the increasingly stringent environmental and product requirements

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