Core-Shell Cracking Catalyst for Steam Enhanced Cracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional refinery systems face challenges in producing greater yields of light olefins and light aromatic compounds from crude oil due to the inaccessibility of large molecules to reactive sites in conventional ZSM-5 zeolites, leading to reduced effectiveness in steam enhanced catalytic cracking.
Innovation Solution
A cracking catalyst with a core-shell structure, where the core comprises ZSM-5 zeolite particles and the shell comprises silica fibers, improves access to reactive sites and reduces blockage by large molecules, enhancing the conversion of crude oil to light olefins and aromatic compounds through a zeolite-seed-assisted micro-emulsion method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ZSM-5 zeolites are used for steam enhanced catalytic cracking, then the catalytic activity is maintained, but large molecules cannot access the reactive sites effectively
Solution Approach 1:
The catalyst particle is segmented into a core-shell structure where the core contains ZSM-5 zeolite particles with reactive sites and the shell provides a porous matrix. This segmentation allows large crude oil molecules to access the core through the shell's larger pores, resolving the accessibility problem while maintaining catalytic activity.
Solution Approach 2:
The ZSM-5 zeolite particles are nested within the shell matrix, creating a hierarchical pore structure. The shell's larger pores serve as transport channels that lead to the smaller pores and reactive sites of the embedded ZSM-5 particles, enabling large molecules to reach the catalyst's active sites.
2Productivity
If conventional cracking catalysts are used, then the process is simple, but coke formation is excessive and blocks reactive sites
Solution Approach 1:
The shell is designed with a controlled porous structure having larger pore sizes than conventional ZSM-5 zeolites. This porous shell facilitates the diffusion of large molecules to reactive sites and allows easier exit of products, reducing residence time and minimizing secondary reactions that lead to coke formation on the catalyst surface.
3Productivity
If multiple complex refinery units are combined, then greater value petrochemical products can be produced, but the device complexity increases
Solution Approach 1:
The core-shell cracking catalyst performs multiple functions within a single unit: it cracks heavy hydrocarbons, produces light olefins, generates aromatic compounds, and resists coke formation. This multi-functionality eliminates the need for multiple separate refinery units (distillation, reforming, solvent treatments, hydro-conversion), simplifying the overall process while maintaining high petrochemical production.
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 efficiently converts crude oil to higher value petrochemical products, achieving increased yields of C2 to C4 olefins and C6 to C10 aromatic compounds while minimizing coke formation, thus simplifying the refining process and improving product selectivity.
Implementation Method 1
contacting a hydrocarbon feed with steam in the presence of a cracking catalyst under steam enhanced catalytic cracking conditions causes at least a portion of the hydrocarbon feed to undergo steam catalytic cracking reactions
Implementation Method 2
the bimodal pore structure of the present cracking catalysts improves transport of larger reactants and reaction products to and from the ZSM-5 active sites in the core
Data Source
AI summary
A process for converting a hydrocarbon feed may comprise contacting a hydrocarbon feed with steam in the presence of a cracking catalyst under steam enhanced catalytic cracking conditions. The contacting the hydrocarbon feed with the steam in the presence of the cracking catalyst may cause at least a portion of the hydrocarbon feed to undergo steam catalytic cracking reactions to produce a cracked effluent comprising C2 to C4 olefins, C6 to C10 aromatic compounds, or both. The cracking catalyst may be a nanoparticle comprising: a core and a shell. The core may comprise one or more ZSM-5 zeolite particles and have an outer surface. The shell may comprise a plurality of fibers extending radially outward from the outer surface of the core. The plurality of fibers may comprise silica.