Fluidized Catalytic Conversion with Serial Reaction Zones for Light Olefins
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Solution Overview
Problem
The yield of ethylene and propylene obtained from existing catalytic cracking conversion systems when processing heavy feedstock oil is not sufficiently high.
Innovation Solution
A fluidized catalytic conversion system with multiple fluidized bed reactors or reaction zones connected in series, utilizing different catalysts and reaction conditions in each zone to enhance the yield of target products, including a reaction unit, catalyst separation unit, and catalyst regeneration unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple reactors or reaction zones are used to construct different reaction environments, then the yield of target products can be improved, but the device complexity increases
Solution Approach 1:
The system divides the catalytic cracking process into multiple reaction zones (first reaction zone with first catalyst, second reaction zone with second catalyst) within a single fluidized bed reactor. Each zone has dedicated catalyst inlets and operates under optimized conditions for specific reactions, thereby increasing light olefin yield without requiring multiple separate reactors
Solution Approach 2:
A single fluidized bed reactor performs multiple functions by incorporating different reaction zones with different catalysts. The first reaction zone performs initial cracking while the second reaction zone performs secondary cracking and aromatization, making one reactor system capable of multiple catalytic transformations
2Manufacturing precision
If different catalysts are used in different reaction zones, then the manufacturing precision of target products is improved, but the device complexity increases
Solution Approach 1:
Different catalysts are introduced into different spatial zones within the reactor. The first catalyst is introduced at the first catalyst inlet for the first reaction zone, while the second catalyst is introduced at the second catalyst inlet for the second reaction zone. This local differentiation of catalyst properties optimizes reaction selectivity in each zone
Solution Approach 2:
The fluidized bed acts as an intermediary that enables the coexistence and interaction of different catalysts. The circulating fluidized bed technology allows catalysts of different types to be introduced, mixed, and circulated together, facilitating seamless transition between different catalytic reactions
3Productivity
If multiple catalysts are circulated and regenerated separately, then the productivity is improved, but the device complexity increases
Solution Approach 1:
The system merges the circulation and regeneration processes of multiple catalysts into a unified system. Both first and second catalysts are circulated through the same fluidized bed and regenerated together in the catalyst regenerator, reducing the need for separate circulation and regeneration systems for each catalyst type
Solution Approach 2:
The catalyst circulation system maintains continuous operation by constantly circulating both catalyst types between the reaction zones and the regenerator. This continuous circulation ensures that catalysts are always available for reaction and are continuously regenerated, maximizing productivity without interruption
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves the yield of ethylene and propylene by allowing for more suitable catalysts and reaction conditions in different reactors or reaction zones, facilitating the relay of catalytic conversion reactions and inhibiting side reactions.
Implementation Method 1
multiple fluidized bed reactors or reaction zones connected in series
Implementation Method 2
catalyst separation unit, in which the oil catalyst mixture from the reaction unit is separated to obtain an oil and gas product and a spent spent catalyst
Implementation Method 3
catalyst regeneration unit, in which the spent spent catalyst from the catalyst separation unit is regenerated and recycled back to the reaction unit
Data Source
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AI summary
A fluidized catalytic conversion system is disclosed, which comprises a reaction unit, a catalyst separation unit, and a catalyst regeneration unit. The reaction unit comprises a first fluidized bed reactor and a second fluidized bed reactor connected in series, or comprises a composite fluidized bed reactor having a first reaction zone and a second reaction zone connected in series. The catalyst separation unit comprises a disengager and a catalyst separator arranged inside or outside the disengager. The catalyst regeneration unit comprises a first catalyst regenerator and a second catalyst regenerator, or comprises a composite catalyst regenerator provided with a first regeneration zone and a second regeneration zone. The fluidized catalytic conversion system can allow the reaction raw materials to undergo different reactions in different reactors or reaction zones under more suitable catalysts and reaction conditions, thereby improving the yield of the target products.