FCC Catalyst Composition for Light Olefin Yield
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Solution Overview
Problem
The existing FCC catalysts face challenges in maximizing light olefin yield while minimizing dry gas formation at higher conversion rates, leading to undesired by-products such as coke, clarified slurry oil, and dry gas, which affects refinery profits.
Innovation Solution
An FCC catalyst composition comprising 25-45 wt% Y-type zeolite, 20-40 wt% silicon oxide, 5-25 wt% alumina, 5-35 wt% clay, and 0.5-3 wt% rare earth oxide, with a silica to alumina ratio of 8:1 to 15:1, is developed, along with a process involving ball milling, slurry formation, spray drying, and calcination to enhance catalytic activity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high conversion rate is achieved in FCC process, then light olefin yield increases, but dry gas formation increases due to over-cracking
Solution Approach 1:
The patent applies parameter changes by optimizing the silica to alumina ratio of Y-type zeolite to 8:1 to 15:1, which modifies the catalytic activity and selectivity. This parameter optimization enables the catalyst to achieve high light olefin yield while suppressing over-cracking that leads to dry gas formation, thus resolving the contradiction between productivity and harmful by-product generation.
Solution Approach 2:
The patent uses a composite catalyst system comprising Y-type zeolite with optimized silica to alumina ratio combined with a matrix containing alumina, silicon oxide, and clay. This composite structure provides both high catalytic activity for light olefin production and controlled selectivity to minimize dry gas formation, effectively balancing the contradiction between conversion efficiency and by-product suppression.
2Productivity
If high catalytic activity is achieved, then conversion of hydrocarbon fraction increases, but formation of undesired by-products (coke, clarified slurry oil, dry gas) increases
Solution Approach 1:
The patent optimizes the silica to alumina ratio parameter of Y-type zeolite to 8:1 to 15:1, which fine-tunes the catalytic activity. This parameter adjustment allows the catalyst to maintain high conversion rates while reducing the formation of undesired by-products such as coke, clarified slurry oil, and dry gas, thereby resolving the contradiction between productivity and by-product formation.
Solution Approach 2:
The patent applies local quality by creating a heterogeneous catalyst structure where Y-type zeolite crystals with optimized silica to alumina ratio are distributed within a matrix of alumina, silicon oxide, and clay. This local optimization of zeolite properties within the composite catalyst enables high activity zones for conversion while other zones provide selectivity control, reducing by-product 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 achieves higher yields of propylene and LPG, reduces low-value hydrocarbon conversion to high-value gasoline range molecules, and minimizes coke and dry gas production, thereby improving refinery efficiency and extending catalyst life.
Implementation Method 1
The catalytic activity of the FCC catalyst is predominantly a function of the number of acid sites present in the catalyst
Implementation Method 2
ball milling precursor of alumina in an aqueous medium for 5 to 120 mins to reduce its average particle size
Implementation Method 3
The homogenized slurry is spray dried, followed by calcining to obtain microspheres
Implementation Method 4
calcining to obtain microspheres. The microspheres are mixed with at least one rare earth compound having a pH value in the range of 2 to 4, to form a suspension. The suspension is heated at a temperature in the range of 60 to 90° C., filtered, washed, dried and calcined
Data Source
AI summary
The present disclosure relates to an FCC catalyst composition and a process for preparing the same. In a first aspect, there is provided an FCC catalyst composition comprising 25 to 45 wt % Y-type zeolite, 20 to 40 wt % silicon oxide, 5 to 25 wt % alumina, 5 to 35 wt % of at least one clay and 0.5 to 3 wt % of at least one rare earth oxide. The weight % of each of the component is with respect to the total weight of the composition. The FCC catalyst composition has an average particle size in the range of 45-120μ. In a second aspect, there is provided a process for preparing the FCC catalyst composition, which uses ball milled pseudoboehmite having an average particle size in the range of 1 to 8 micron and the whole process is carried out at a pH value in the range of 6 to 7.