FCC Catalyst Attrition Resistance via Dual Silica Sources
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Solution Overview
Problem
Existing catalysts face challenges in achieving a balance between active site accessibility and physical strength, particularly in terms of attrition resistance, which affects their performance in hydrocarbon cracking processes.
Innovation Solution
A catalyst composition comprising multiple silica sources, specifically sodium stabilized basic colloidal silica and acidic colloidal silica or polysilicic acid, combined with quasicrystalline and microcrystalline boehmite, and clay, is used to create a particulate FCC catalyst with improved attrition resistance and accessibility, achieved through a process involving slurry formation, pH adjustment, and shaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single silica source is used in the catalyst, then the preparation process is simple, but the attrition resistance and accessibility are insufficient
Solution Approach 1:
The patent employs composite materials by combining two different silica sources (sodium stabilized basic colloidal silica and acidic colloidal silica or polysilicic acid) with boehmite and clay to form a multi-component catalyst system. This composite approach allows the catalyst to achieve both high attrition resistance and accessibility, as each silica source contributes different properties that complement each other in the catalyst matrix.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the pH level during the slurry preparation process. By controlling the pH to be between 2 and 4, the patent optimizes the dissolution and distribution of silica species in the slurry, which directly influences the final catalyst's attrition resistance and accessibility. This parameter control enables better integration of multiple silica sources into the catalyst matrix.
2Strength
If multiple silica sources are used to improve attrition resistance, then the physical strength increases, but the preparation process becomes more complex
Solution Approach 1:
The patent simplifies the preparation process by implementing specific parameter controls, particularly pH adjustment to 2-4, which optimizes the dissolution and distribution of silica species in the slurry. This parameter control enables better integration of multiple silica sources into the catalyst matrix while maintaining process feasibility.
Solution Approach 2:
The patent applies preliminary action by pre-adjusting the pH of the slurry before adding all components. This preliminary pH adjustment creates optimal conditions for silica dissolution and distribution, allowing subsequent components to be added more efficiently and reducing the overall complexity of the preparation process.
3Ease of operation
If the catalyst is designed for high accessibility, then the active site accessibility improves, but the attrition resistance decreases
Solution Approach 1:
The patent employs composite materials by combining two different silica sources (sodium stabilized basic colloidal silica and acidic colloidal silica or polysilicic acid) with boehmite and clay to form a multi-component catalyst system. This composite approach allows the catalyst to achieve both high attrition resistance and accessibility, as each silica source contributes different properties that complement each other in the catalyst matrix.
Solution Approach 2:
The patent applies local quality by creating different functional zones within the catalyst particle. The multiple silica sources are distributed to provide both structural support (for attrition resistance) and porous pathways (for accessibility) in specific regions of the catalyst matrix, allowing simultaneous optimization of both properties.
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 resulting catalyst exhibits enhanced attrition resistance, higher accessibility, and stability, leading to improved performance in hydrocarbon cracking, with increased retention of zeolite and surface area even after deactivation.
Implementation Method 1
adjusting the pH of the slurry to a value above 3
Implementation Method 2
a bound catalyst structure is formed
Data Source
AI summary
Process for the preparation of a catalyst and a catalyst comprising the use of more than one silica source is provided herein. Thus, in one embodiment, the invention provides a particulate FCC catalyst comprising about 5 to about 60 wt % one or more zeolites, about 15 to about 35 wt % quasicrystalline boehmite (QCB), about 0 to about 35 wt % microcrystalline boehmite (MCB), greater than about 0 to about 15 wt % silica from sodium stabilized basic colloidal silica, greater than about 0 to about 30 wt % silica from acidic colloidal silica or polysilicic acid, and the balance clay and the process for making the same. This process results in attrition resistant catalysts with a good accessibility.