Fluid Catalytic Cracking Catalyst Composition for Metal Tolerance
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Solution Overview
Problem
Current catalyst compositions for fluid catalytic cracking of heavy petroleum feeds face challenges in maintaining high LPG and propylene selectivity while handling high concentrations of metal contaminants like nickel and vanadium, as well as high Conradson Carbon Residue (CCR), which reduces their metal tolerance and efficiency.
Innovation Solution
A catalyst composition comprising 4-8% pentasil zeolite, 10-25% ultra-stable Y (USY) or rare earth exchanged USY (REUSY) zeolite, 6-15% alumina as a bottom upgradation component, and 0.4-3% metal trap component, specifically designed to handle high nickel and vanadium levels, with the metal trap component including vanadium and nickel trap components such as lanthanum, cerium, and bismuth, allowing for effective processing of heavy feeds with high metal content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalyst compositions are used for fluid catalytic cracking of heavy petroleum feeds, then basic cracking activity is maintained, but metal tolerance and selectivity for LPG and propylene deteriorate in the presence of high nickel and vanadium concentrations
Solution Approach 1:
The catalyst is segmented into multiple functional components: USY zeolite (10-25 wt%) for base cracking activity, pentasil zeolite (4-8 wt%) for shape-selective propylene production, metal trap agents (0.4-3 wt%) for metal tolerance, and alumina matrix (6-15 wt%) for structural support. This segmentation allows each component to specialize in one function, resolving the contradiction between maintaining selectivity and tolerating metals.
Solution Approach 2:
The invention uses a composite catalyst system combining ultra-stable Y zeolite, pentasil zeolite, metal trap agents (such as rare earth elements, phosphorus, and transition metals), and alumina matrix. This composite structure integrates multiple materials with complementary properties: USY provides cracking activity, pentasil provides shape selectivity, metal traps provide tolerance to Ni and V, and alumina provides mechanical strength. The synergistic combination resolves the technical contradiction by making the overall system tolerant to metals while maintaining high LPG and propylene selectivity.
2Productivity
If heavy feeds with high Conradson Carbon Residue are processed, then feedstock utilization is improved, but catalyst deactivation and coke formation increase
Solution Approach 1:
The alumina matrix (6-15 wt%) acts as an intermediary between the heavy feed and the zeolite active sites. It provides a porous structure that facilitates mass transfer of heavy molecules while protecting the zeolite from excessive coking. The metal trap agents also serve as intermediaries that selectively bind metal contaminants before they can poison the zeolite active sites, thereby maintaining catalyst stability during heavy feed processing.
Solution Approach 2:
The invention optimizes the composition parameters of the catalyst: USY zeolite content (10-25 wt%) balances cracking activity with coke tolerance, pentasil zeolite (4-8 wt%) enhances propylene selectivity while controlling coke formation, and metal trap agents (0.4-3 wt%) are tuned to provide optimal metal binding capacity. These parameter optimizations enable the catalyst to maintain stability when processing heavy feeds with high CCR.
3Reliability
If metal trap agents are added to handle feed metals, then metal tolerance is improved, but catalyst complexity and manufacturing difficulty increase
Solution Approach 1:
The invention merges the metal trap function with the existing catalyst structure by incorporating metal trap agents (such as rare earth elements, phosphorus, and transition metals) into the catalyst formulation during manufacturing. This integration combines multiple functions (cracking, shape selectivity, and metal trapping) into a single unified catalyst system, reducing the need for separate additive injection systems and simplifying the overall process complexity.
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 high selectivity for LPG and ethylene, maintaining activity and selectivity even at elevated metal concentrations, enhancing propylene yield up to 27% and ethylene yield in dry gas, while reducing coke selectivity and hydrogen yield, thus improving overall cracking efficiency.
Implementation Method 1
metal trap component comprises at least one of a vanadium trap component and a nickel trap component
Implementation Method 2
catalyst composition comprising 4-8% pentasil zeolite, 10-25% ultra-stable Y (USY) or rare earth exchanged USY (REUSY) zeolite
Data Source
AI summary
The present invention provides a catalyst composition for use in a catalytic cracking process, said catalyst composition comprises 3.5 to 15.5 % of pentasil zeolite, 9 to 40 % of ultra-stable Y (USY) or rare earth exchanged USY (REUSY) zeolite, 3.5 to 15 % of large pore active matrix based bottom up gradation component and 0.3 to 3 % of a metal trap component, the percentage being based on weight of the catalyst composition. The present invention also provides a process for preparing the said catalyst composition and a catalytic cracking process comprising contacting the said catalyst composition with a feedstock.