Composite FCC Catalyst for Olefin Yield and Distillate Preservation
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Solution Overview
Problem
Conventional Fluid Catalytic Cracking (FCC) catalysts face limitations in enhancing C3 to C4 olefin yields while minimizing losses of gasoline, heavy naphtha, and light cycle oil, often requiring high operating temperatures and low weight hour space velocity, which affects catalyst robustness and selectivity.
Innovation Solution
A composite FCC catalyst composition comprising 10-25 wt % rare earth exchanged USY zeolite, 5-20 wt % stabilized pentasil zeolite, 2-8 wt % phosphorous compound, 20-45 wt % clay, 5-25 wt % silica, and 0.5 to 3 wt % mixed metal oxide, specifically copper aluminate spinel, is developed to enhance light olefin selectivity and reduce distillate losses, with a process involving slurry preparation, milling, spray drying, and calcination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional FCC catalysts are used to enhance C3 to C4 olefin yields, then olefin production increases, but losses of gasoline, heavy naphtha, and light cycle oil increase
Solution Approach 1:
The patent employs a composite catalyst system comprising Y-zeolite (20-40 wt%), ZSM-5 zeolite (5-20 wt%), and alumina matrix (30-50 wt%). The Y-zeolite provides bulk cracking activity for converting heavy feeds, while ZSM-5 acts as a shape-selective catalyst that enhances olefin production through its specific pore structure. This composite approach allows simultaneous optimization of olefin yield and preservation of gasoline/d distillate products by distributing catalytic functions across different materials with complementary properties.
Solution Approach 2:
The catalyst design implements local quality by creating distinct functional zones within the composite structure. The ZSM-5 component provides localized shape-selective cracking sites that preferentially produce C3-C4 olefins, while the Y-zeolite provides broader cracking activity. The alumina matrix provides structural support and additional active sites. This spatial and functional differentiation allows the catalyst to perform multiple functions simultaneously with optimized performance in each area.
2Quantity of substance
If high operating temperatures are used to enhance olefin yields, then olefin production increases, but catalyst robustness and selectivity deteriorate
Solution Approach 1:
The composite catalyst structure with alumina matrix (30-50 wt%) provides high thermal stability and mechanical strength, allowing the catalyst to withstand elevated operating temperatures without degradation. The crystalline zeolite components (Y-zeolite and ZSM-5) are embedded in this thermally robust matrix, which protects them from sintering and structural collapse. This enables the system to operate at higher temperatures that enhance olefin yields while maintaining catalyst integrity and selectivity.
Solution Approach 2:
The patent optimizes operating parameters including weight hour space velocity (WHSV) and temperature to maximize olefin production while maintaining catalyst stability. By controlling WHSV within specific ranges and utilizing the composite catalyst's inherent thermal stability, the system can operate at elevated temperatures that favor olefin formation kinetics without causing excessive catalyst deactivation or loss of selectivity.
3Quantity of substance
If low weight hour space velocity is used to enhance olefin yields, then olefin production increases, but processing efficiency decreases
Solution Approach 1:
The composite catalyst system with dual zeolite components provides enhanced catalytic activity per unit time, allowing higher WHSV operation. The ZSM-5 component specifically accelerates olefin-producing reactions through its shape-selective mechanism, while Y-zeolite provides rapid bulk cracking. This synergistic effect increases the rate of olefin formation, enabling the system to achieve high olefin yields at elevated WHSV values that maintain processing efficiency.
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 achieves enhanced production of total olefins, propylene selectivity, and gasoline yield with minimal loss of gasoline and distillates, operating effectively at lower temperatures and catalyst/oil ratios, improving thermal and mechanical stability and surface area dispersion.
Implementation Method 1
Fluid catalytic cracking (FCC) catalyst composition for upgrading low value, high boiling hydrocarbon feed stock
Implementation Method 2
a process involving slurry preparation, milling, spray drying, and calcination
Data Source
AI summary
The present invention provides a catalyst composition comprising rare earth exchanged USY zeolite (REUSY); pentasil zeolite; phosphorous compound; clay, silica, alumina, and spinel to enhance the catalytic activity and selectivity for light olefins in FCC operation conditions. The present invention also provides a process for the preparation of Light olefin enhancing catalyst composition with high propylene yield and coke selectivity.