FCC Catalyst Composition for Propylene Selectivity
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Solution Overview
Problem
The fluid catalytic cracking process in petroleum refining faces challenges in selectivity, producing excessive dry gas and insufficient propylene, despite advancements in catalysts like zeolites, necessitating a catalyst composition that enhances propylene content while reducing dry gas yield.
Innovation Solution
A catalyst composition comprising a non-zeolitic material (76-86%), zeolite-1 (3-18%), and modified zeolite-2 (2-12%) with metals (0.1-2.5%) is developed, along with a specific FCC apparatus design, including riser configurations and quenching streams, to optimize hydrocarbon cracking and reduce dry gas production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If zeolites like ZSM-5 are used to enhance propylene production, then propylene selectivity is improved, but dry gas yield increases
Solution Approach 1:
The patent uses a composite catalyst system combining zeolite Y (3-18 wt%), zeolite ZSM-5 (2-12 wt%), and matrix material (76-86 wt%). This composite approach allows the zeolite Y to provide high conversion activity while zeolite ZSM-5 contributes to propylene selectivity, and the matrix material controls the overall reaction environment to minimize dry gas formation, thus resolving the contradiction between propylene selectivity and dry gas yield
Solution Approach 2:
The patent optimizes multiple parameters including the weight percentages of different catalyst components (zeolite Y: 3-18%, zeolite ZSM-5: 2-12%, matrix: 76-86%), metal modification levels (0.1-2.5% on zeolite-2), reaction temperature, and space velocity. By carefully adjusting these parameters, the catalyst achieves high propylene selectivity while controlling dry gas formation through optimized reaction conditions and catalyst composition
2Productivity
If traditional catalytic cracking is used, then conversion efficiency is improved, but product selectivity deteriorates
Solution Approach 1:
The patent employs a composite catalyst consisting of zeolite Y (3-18 wt%) for high conversion activity, zeolite ZSM-5 (2-12 wt%) for shape-selective propylene production, and matrix material (76-86 wt%) for structural support and reaction control. This multi-component composite system simultaneously achieves high conversion efficiency and improved product selectivity, resolving the contradiction between productivity and manufacturing precision
3Productivity
If high temperature cracking is used, then conversion rate is improved, but catalyst fluidization and dry gas formation increase
Solution Approach 1:
The patent optimizes reaction parameters including temperature, space velocity, and catalyst composition to achieve high conversion rates while controlling dry gas formation. The matrix material (76-86 wt%) provides thermal stability and controls the reaction environment, allowing efficient cracking at optimized temperatures without excessive dry gas formation
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
The catalyst composition significantly increases propylene yield and decreases dry gas content, improving the selectivity and efficiency of the cracking process, as demonstrated by experimental results showing enhanced propylene production with reduced dry gas and coke formation.
Implementation Method 1
Fluid catalytic cracking (FCC) process and apparatus for production of light olefins
Implementation Method 2
Modern reactors are commonly run at high temperatures, wherein the finely divided catalyst can get fluidized, allowing better catalyst-substrate interactions (fluid catalyzed cracking or FCC)
Implementation Method 3
a quenching stream feed nozzle which is connected to the upper dilute riser at a height of 0 to 40% above the dense riser
Data Source
AI summary
The instant disclosure provides a composition for fluid catalytic cracking of petroleum based feedstock into useful short chain olefins. The composition comprising: 76-86% of a non-zeolitic material; and 2-30% of at least one zeolite material, the percentage being based on weight of the catalyst composition, wherein one of the zeolites has been modified with 0.1-2.5 wt % metal. The said catalyst was found to be selective in enhancing the usable propylene gas content, while reducing the undesirable dry gas content of the cracked olefinic products. The present disclosure also provides a process for the preparation of the composition. The present disclosure also provides an apparatus (100) and process (200) for fluid catalytic cracking to obtain light olefins. The apparatus comprises a second riser (33) that includes a lower dense riser (2) and upper dilute riser (3). Further, the lower dense riser (2) has a diameter that is 1.1 to 2 times that of the upper dilute riser (3).