Catalytic Cracking Catalyst Pore Extender Macropore Volume
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Solution Overview
Problem
Existing catalysts for catalytic cracking of hydrocarbon oils have low macropore content, leading to insufficient capacity for cracking heavy oils and low yields of light olefins and propylene.
Innovation Solution
A catalyst preparation process that introduces a pore-extender, such as potassium sulfate, and metal halides to increase macropore volume, enhance coke-tolerance, and improve abrasion resistance, using a substrate with a molecular sieve composition including MFI-structured zeolite and Y-zeolite, which increases the catalyst's cracking capacity and propylene yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing catalyst formulations are used, then the catalyst structure is simple and easy to manufacture, but the macropore content is low leading to insufficient cracking capacity for heavy oils
Solution Approach 1:
The patent introduces a pore-extender substance (such as colloidal silica, water glass, or aluminum silicate) into the catalyst formulation to increase macropore content. This directly addresses the low macropore issue in existing catalysts, enabling better access to heavy oil molecules and improving cracking capacity while maintaining a manageable composition structure.
Solution Approach 2:
The patent creates a composite catalyst system combining traditional catalyst components (molecular sieves like ZSM-5 and Y-zeolite, alumina substrate) with a pore-extender additive. This composite approach allows the catalyst to simultaneously maintain its catalytic functionality while gaining enhanced macropore structure for heavy oil processing capability.
2Productivity
If existing catalyst formulations are used, then the manufacturing process is simple, but the yield of light olefins and propylene is low
Solution Approach 1:
The patent modifies the catalyst's physical structure by incorporating pore-extenders that increase macropore volume and adjust pore size distribution. This parameter change in the catalyst's porous structure enhances its ability to produce light olefins and propylene from heavy oils without fundamentally changing the manufacturing process complexity.
Solution Approach 2:
The pore-extender is introduced to specifically create macropores in the catalyst structure, providing localized pathways for heavy oil access and product diffusion. This local structural enhancement targeted at specific pore regions improves light olefin yield while keeping the overall manufacturing process relatively simple.
3Reliability
If existing catalyst formulations are used, then the catalyst composition is simple, but the coke-tolerance and coke-resistance are insufficient
Solution Approach 1:
The increased macropore content achieved by adding pore-extenders provides better pathways for coke removal and reduces coke deposition in micropore regions. This porous structure modification enhances the catalyst's resistance to deactivation by coke without significantly complicating the formulation.
4Strength
If existing catalyst formulations are used, then the catalyst structure is simple, but the abrasion resistance is insufficient
Solution Approach 1:
The pore-extender acts as a binding component in the catalyst composite structure, potentially improving mechanical strength and abrasion resistance by filling voids and creating a more robust matrix. This composite approach enhances physical durability while maintaining formulation manageability.
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 process results in a catalyst with improved cracking capacity for heavy oils, increased propylene yield, and enhanced coke-resistance, as demonstrated by higher propylene yield and lower coke and heavy oil yields compared to prior art processes.
Implementation Method 1
introduces a pore-extender, such as potassium sulfate, to increase macropore volume
Implementation Method 2
a catalyst with improved cracking capacity for heavy oils, increased propylene yield... using a substrate with a molecular sieve composition including MFI-structured zeolite and Y-zeolite
Implementation Method 3
introduces... metal halides to increase macropore volume, enhance coke-tolerance, and improve abrasion resistance
Implementation Method 4
catalytic cracking of hydrocarbon oils... higher propylene yield and lower coke and heavy oil yields
Data Source
AI summary
A catalyst for catalytically cracking hydrocarbon oils contains a substrate comprising alumina and a molecular sieve, characterized in that the pore distribution of said catalyst is 5-70% of the <2 nm pores, 5-70% of the 2-4 nm pores, 0-10% of the 4-6 mn pores, 20-80% of the 6-20 nm pores, and 0-40% of the 20-100 nm pores, based on the pore volume of pores having a size of no more than 100 nm. The catalyst of this invention has a large BET pore volume, a high capacity for cracking heavy oils, and a high capacity for resisting coking.