Nickel-Molybdenum Catalyst for Heavy Hydrocarbon Pitch Conversion
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Solution Overview
Problem
Existing catalyst compositions for hydroprocessing of heavy hydrocarbon feedstocks face challenges in achieving high conversion of pitch and micro carbon residue (MCR) while minimizing hydrogen consumption and maintaining stability under severe conditions.
Innovation Solution
A catalyst composition with a molybdenum content of less than 12 wt% and a nickel-to-molybdenum weight ratio exceeding 0.25, supported by an alumina material with a narrow pore distribution and specific physical properties, such as a median pore diameter between 100 Å and 140 Å, is used for hydroconversion, reducing hydrogen consumption and maintaining high catalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalyst compositions are used for hydroconversion of heavy hydrocarbon feedstocks, then pitch component conversion can be achieved, but hydrogen consumption is high
Solution Approach 1:
The invention changes the compositional parameters of the catalyst by limiting molybdenum content to less than 12 wt% and setting the nickel-to-molybdenum weight ratio to greater than 0.25. This parameter optimization enables high pitch conversion while reducing hydrogen consumption, as the controlled metal composition improves catalytic efficiency in breaking down heavy hydrocarbon molecules with fewer hydrogen requirements.
Solution Approach 2:
The invention employs a composite catalyst system combining nickel and molybdenum components on an alumina support with specifically controlled pore distribution (median pore diameter 100-140 Å). This composite structure creates synergistic effects where nickel promotes dehydrogenation and molybdenum facilitates hydrodesulfurization and hydrodemetallization, achieving high pitch conversion with optimized hydrogen utilization.
2Productivity
If conventional catalyst compositions are used for hydroconversion, then some pitch conversion is achieved, but catalytic activity decreases under severe conditions
Solution Approach 1:
The invention optimizes physical parameters of the alumina support including median pore diameter (100-140 Å), pore volume (0.35-0.65 mL/g), and surface area (150-350 m²/g). These parameter changes enhance the support's ability to maintain catalyst dispersion and prevent sintering under severe hydroconversion conditions, ensuring stable catalytic activity over extended operation periods.
Solution Approach 2:
The invention creates local quality variations within the catalyst structure by controlling the pore size distribution and metal dispersion patterns. The narrow pore distribution (100-140 Å median diameter) provides optimal local environments for reactant access and product diffusion, while the controlled nickel-to-molybdenum ratio creates localized active sites with enhanced stability and resistance to deactivation under severe processing conditions.
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 composition achieves high pitch and MCR conversion with low hydrogen consumption and exhibits improved stability, outperforming prior art catalysts by maintaining high activity even under severe hydroconversion conditions.
Implementation Method 1
a catalyst composition and a process that uses the catalyst composition for the hydroconversion of a heavy hydrocarbon feedstock
Data Source
AI summary
A catalyst composition that provides for a high percentage conversion of the pitch component of a heavy hydrocarbon feedstock and a process of using the catalyst composition. The catalyst composition comprises a nickel component, a molybdenum component in an amount less than 12 wt % of the catalyst composition, and it may also include an alumina support material having special properties. The weight ratio of the nickel component-to-molybdenum component exceeds 0.25, and the support material preferably has a median pore diameter of from 100-140 Å. The catalyst composition has a characteristically unique Raman spectrum that distinguishes it over other compositions.