Mesoporous Composite Catalyst for Heavy Oil Hydrocracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydrotreating of heavy crude oils and residues is challenging due to the presence of refractory compounds, which cause diffusion problems and lead to catalyst deactivation, as existing catalysts struggle with the removal of heteroatoms and metals, and the formation of coke deposits.
Innovation Solution
A composite catalyst support comprising mesoporous materials, alumina, and molecular sieves with metals of Groups VIB and VIII, specifically using SBA-15 and boehmite/zeolite/SBA-15 formulations, is developed to enhance hydrocracking efficiency and stability in multi-bed catalyst systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalysts are used for hydrotreating heavy crude oils, then the catalyst structure is simple and easy to manufacture, but the catalyst suffers from diffusion problems and rapid deactivation due to refractory compounds and asphaltenes
Solution Approach 1:
The patent employs a composite catalyst structure combining mesoporous materials (SBA-15, MCM-41) with alumina and molecular sieves (zeolites). This composite approach creates a hierarchical pore system with both mesopores (2-50 nm) for bulk diffusion and micropores for selective catalysis, resolving the contradiction between stability and complexity by integrating multiple functional materials into a synergistic system that prevents rapid deactivation while managing structural complexity through systematic design
2Area of stationary object
If the catalyst pore diameter is small to increase surface area, then the surface area increases, but large refractory molecules cannot diffuse into the pores effectively
Solution Approach 1:
The catalyst structure is segmented into multiple pore size levels: mesopores (2-50 nm) provide bulk diffusion pathways for large refractory molecules, while micropores (0.3-2 nm) provide high surface area for catalytic reactions. This segmentation allows different pore sizes to perform specialized functions, resolving the contradiction by creating a hierarchical structure where mesopores facilitate ease of operation (diffusion) and micropores maximize surface area
Solution Approach 2:
The patent transitions from a single-pore-size structure to a hierarchical multi-dimensional pore system. Mesopores provide one dimension of transport (bulk diffusion), while micropores provide another dimension (surface reaction sites). This dimensional approach allows simultaneous optimization of diffusion access and surface area by operating at different spatial scales within the same catalyst particle
3Reliability
If metals are removed from the feed, then the catalyst deactivation from metal deposition is reduced, but the pressure drop increases due to metal guard materials
Solution Approach 1:
The patent changes the chemical parameter of the catalyst support by incorporating mesoporous materials with specific surface properties and pore structures that are inherently more resistant to metal poisoning. The high surface area and controlled pore architecture of SBA-15 and MCM-41 provide alternative pathways that reduce the impact of metal deposition, allowing the system to maintain catalyst activity without relying heavily on metal guard materials, thus reducing pressure drop
4Productivity
If asphaltenes are present in the feed, then the feed composition remains unchanged, but coke deposits form rapidly and deactivate the catalyst
Solution Approach 1:
The patent converts the harmful effect of asphaltenes into a beneficial outcome by using the high surface area and specific pore structure of mesoporous materials to promote controlled cracking and conversion of asphaltenes into valuable products. The hierarchical pore system allows asphaltenes to access active sites while preventing uncontrolled coking, thus converting what would be catalyst-deactivating material into productive feedstock for middle distillate 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 system improves hydrodesulfurization, hydrodenitrogenation, hydrodeasphaltenization, and hydrodemetallization conversions, maintaining activity and stability over long time-on-stream, and increases the production of middle distillates while reducing vacuum residue production.
Implementation Method 1
The properties of the catalysts used depend on the type of feed to be processed... pore diameter, surface area, pore volume distribution, and surface acidity
Implementation Method 2
the large and complex molecules that contain the heteroatoms present diffusion problems in the pores of the catalyst
Implementation Method 3
A composite catalyst support comprising mesoporous materials, alumina, and molecular sieves with metals of Groups VIB and VIII, specifically using SBA-15 and boehmite/zeolite/SBA-15 formulations, is developed to enhance hydrocracking efficiency
Data Source
AI summary
A hydrocracking catalyst having a support of a composite of mesoporous materials, molecular sieves and alumina, is used in the last bed of a multi-bed system for treating heavy crude oils and residues and is designed to increase the production of intermediate distillates having boiling points in a temperature range of 204° C. to 538° C., decrease the production of the heavy fraction (>538° C.), and increase the production of gasoline fraction (<204° C.). The feedstock to be processed in the last bed contains low amounts of metals and is lighter than the feedstock that is fed to the first catalytic bed.