Fluidized Catalytic Cracking Reactor for Lower Dry Gas and Coke
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing catalytic cracking technologies face challenges in efficiently converting heavy hydrocarbon oils into high-value products like light olefins and aromatics, often resulting in high dry gas and coke yields, and struggle with product distribution adjustments, while facing resource shortages and high production costs.
Innovation Solution
A process and system utilizing a reactor configuration with a dilute-phase transport fluidized bed and a fast fluidized bed connected in series, where the axial solid fraction of the catalyst in the fast fluidized bed is controlled between 0.1 to 0.2, allowing for improved catalyst-to-oil ratio and reaction time, supplemented by additional catalysts to enhance reaction efficiency and product selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalytic cracking is used to convert heavy hydrocarbon oils, then light olefins and aromatics are produced, but dry gas and coke yields are high
Solution Approach 1:
The reactor is divided into two distinct zones: a dilute-phase transport fluidized bed for initial cracking and a fast fluidized bed for secondary cracking. This segmentation allows different reaction conditions in each zone, optimizing both conversion efficiency and product selectivity while minimizing dry gas and coke formation.
Solution Approach 2:
The patent controls the axial solid fraction of catalyst in the fast fluidized bed within 0.05-0.2, and adjusts catalyst-to-oil ratio and residence time parameters. These parameter changes enable precise control over reaction pathways, improving conversion to valuable products while reducing unwanted byproducts.
2Productivity
If catalyst-to-oil ratio and reaction time are increased to improve conversion, then product selectivity improves, but reactor complexity increases
Solution Approach 1:
The reactor is segmented into two zones with distinct functions: the dilute-phase zone for initial cracking and the fast fluidized bed for secondary cracking. This segmentation enables independent optimization of catalyst-to-oil ratios and residence times in each zone, achieving high product selectivity while maintaining manageable system complexity through functional division.
Solution Approach 2:
The patent employs dynamic control of catalyst circulation and axial solid fraction distribution between the two reactor zones. By dynamically adjusting catalyst flow and residence time parameters, the system achieves high conversion and selectivity without requiring overly complex fixed configurations.
3Productivity
If conventional steam cracking is used to produce light olefins, then production capacity is achieved, but energy consumption and CO2 emission are high
Solution Approach 1:
The patent replaces the high-energy thermal steam cracking process with a catalytic cracking system using fluidized bed reactors. This substitution uses catalyst-mediated reactions at lower temperatures, significantly reducing energy consumption and CO2 emissions while maintaining high production capacity for light olefins and aromatics.
Solution Approach 2:
By changing the fundamental reaction parameters from high-temperature thermal cracking to lower-temperature catalytic cracking, the system achieves comparable productivity with dramatically reduced energy input. The controlled axial solid fraction and catalyst circulation enable efficient conversion at lower energy costs.
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
This approach enhances the conversion of inferior heavy oils into high-value chemicals like ethylene and propylene, reduces dry gas and coke production, and improves product distribution, addressing resource scarcity and economic challenges in the petrochemical industry.
Implementation Method 1
contacting a hydrocarbon oil feedstock with a catalytic cracking catalyst for reaction in a reactor comprising a dilute-phase transport fluidized bed and a fast fluidized bed connected in series
Implementation Method 2
reactor comprising a dilute-phase transport fluidized bed and a fast fluidized bed connected in series
Data Source
AI summary
A system for catalytic cracking of hydrocarbon oils has a catalytic cracking reactor, a catalyst separation device, an optional reaction product separator, and a regenerator. A catalytic cracking reactor has a dilute-phase transport fluidized bed and a fast fluidized bed connected in series for reaction. In the fast fluidized bed, the axial solid fraction ε of the catalyst is controlled within the range of about 0.1 to about 0.2. When used for catalytic cracking of hydrocarbon oil feedstocks, particularly heavy feedstock oils, the process and system show lower yields of dry gas and coke, and good product distribution.