Phosphorus-Modified FCC Catalyst Reduces Coke and Hydrogen Yields
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Solution Overview
Problem
Current fluid catalytic cracking (FCC) catalysts face challenges in minimizing coke and hydrogen yields, especially when processing resid feeds contaminated with transition metals like nickel and vanadium, which lead to increased coke and hydrogen production, compromising catalyst activity and selectivity.
Innovation Solution
A phosphorus-modified FCC catalyst composition is developed, comprising catalytic microspheres with a non-zeolitic component, transition alumina, intergrown zeolite, rare earth components, and a phosphorus component, which are formed through specific manufacturing processes to prevent nickel and vanadium from increasing coke and hydrogen yields during hydrocarbon cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional FCC catalysts are used to process resid feeds, then cracking activity is maintained, but coke and hydrogen yields increase due to metal contaminants
Solution Approach 1:
Phosphorus is introduced as an intermediary substance that mediates between the metal contaminants (Ni, V) and the zeolite catalyst. The phosphorus forms phosphate species that interact with the metal contaminants, preventing them from catalyzing unwanted dehydrogenation reactions that lead to excessive coke and hydrogen production, while allowing the zeolite to maintain its cracking activity
Solution Approach 2:
The chemical composition of the catalyst is modified by adding phosphorus, which changes the chemical environment and interaction mechanisms between metal contaminants and the catalyst surface. This parameter change transforms the catalyst's response to metal contaminants, reducing their harmful effects on coke and hydrogen yields
2Productivity
If nickel and vanadium contaminants are present in resid feeds, then dehydrogenation reactions increase, but this leads to excessive hydrogen and coke production
Solution Approach 1:
The phosphorus modification converts the harmful effect of metal contaminants into a beneficial interaction. Instead of allowing Ni and V to catalyze unwanted dehydrogenation reactions, the phosphorus creates phosphate species that interact with these metals in a controlled manner, redirecting the reaction pathways to reduce excessive hydrogen and coke production while maintaining useful cracking activity
3Productivity
If metal contaminants deposit on the catalyst, then catalytic activity changes, but zeolite framework structure is destroyed
Solution Approach 1:
Phosphorus is pre-introduced into the catalyst structure before the catalyst encounters metal contaminants during operation. This preliminary action creates phosphate species that are positioned to interact with and sequester metal contaminants as they deposit, preventing the metals from directly attacking and destroying the zeolite framework structure
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 phosphorus-modified catalyst effectively reduces hydrogen and coke yields while enhancing zeolite surface area retention and catalyst stability, improving the selectivity and activity of the catalyst, particularly when processing resid feeds.
Implementation Method 1
the phosphorus component interacts with nickel and vanadium to reduce their ability to increase coke and hydrogen yields
Data Source
AI summary
Described are fluid catalytic cracking (FCC) compositions, methods of manufacture and use. FCC catalyst compositions comprise catalytic microspheres containing a zeolite, a non-zeolitic component, and a rare earth component. The microspheres are modified with phosphorus. The FCC catalyst composition can be used to crack hydrocarbon feeds, particularly resid feeds containing high V and Ni, resulting in lower hydrogen and coke yields.