Bulk Catalyst Stability via Gas-Phase Sulfidation
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Solution Overview
Problem
Existing catalysts for ultra-low sulfur processing lack long-term stability and integrity, which is crucial for meeting stringent environmental regulations requiring high desulfurization activity in distillate fuels without expensive refinery modifications.
Innovation Solution
A bulk metallic catalyst comprising a Group VIII metal, a Group VIB metal, and an organic compound-based component with a stabilizer, which is sulfided at low temperatures to enhance stability and activity, utilizing a gas-phase sulfidation process to maintain catalyst integrity and activity over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalysts are used for ultra-low sulfur processing, then high desulfurization activity can be achieved, but long-term stability and integrity deteriorate
Solution Approach 1:
The patent employs a composite catalyst structure combining Group VIII metal (Co or Ni) with Group VIB metal (Mo or W) in a bulk metallic formulation. This composite approach creates synergistic effects where the combination of metals provides both high initial desulfurization activity and enhanced long-term stability, resolving the contradiction between productivity and reliability
Solution Approach 2:
The patent utilizes low-temperature gas-phase sulfidation (below conventional temperatures) to transform the catalyst precursor into the active sulfided form. This parameter change in sulfidation temperature and phase maintains metal dispersion and prevents aggregation, thereby preserving catalyst integrity and stability over extended operation while maintaining high activity
2Productivity
If catalyst surface area is increased to enhance activity, then desulfurization performance improves, but catalyst stability and integrity worsen
Solution Approach 1:
The patent creates a bulk metallic catalyst with heterogeneous local structures - the exterior surface provides active sites for desulfurization while the interior bulk maintains structural integrity. The low surface area (16-50 m²/g) bulk formulation ensures that the majority of the catalyst mass remains in a stable, aggregated state that resists degradation, while sufficient active surface is maintained for high activity
Solution Approach 2:
The patent employs a stabilizer component in the catalyst formulation that preemptively prevents metal aggregation and structural degradation before they can occur during operation. This stabilizer acts as a protective agent that maintains metal dispersion and prevents sintering, cushioning against the natural tendency of high-surface-area catalysts to degrade over time
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 achieves improved long-term stability and hydroprocessing activity, ensuring effective desulfurization of distillate fuels while adhering to stringent environmental standards without requiring costly refinery upgrades.
Implementation Method 1
The sulfided bulk metallic catalyst is formed by sulfiding a catalyst precursor composition comprising a Group VIII metal, a Group VIB metal, and from about 10 wt. % to about 60 wt. % of a organic compound-based component
Implementation Method 2
the bulk metallic catalyst is formed by gas-phase sulfidation at a temperature of 350° C. or less
Implementation Method 3
the organic compound-based component is based on at least one organic complexing agent and at least one stabilizer
Implementation Method 4
The catalysts are further characterized as a) including a stabilizer as part of the organic complexing agent
Data Source
AI summary
Bulk catalysts that include a Group VI metal, a Group VIII metal, and at least 10-60% of an organic compound based component are formed. The bulk catalysts have increased stability through the use of a stabilizer in the organic compound based component, the use of an improved gas phase sulfidation, or a combination thereof. The bulk catalysts are suitable for hydroprocessing of hydrocarbon feeds.