Shaped Ebullated Bed Catalyst Sediment Reduction
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Solution Overview
Problem
Existing processes for hydroconversion of heavy hydrocarbon feedstocks often result in undesirable sediment formation, which is not adequately addressed by current technologies, particularly in ebullated bed reactor systems.
Innovation Solution
The use of a small particle size, shaped hydroprocessing catalyst with a calcined alumina support and low macroporosity, specifically designed with a cross section perimeter-to-cross sectional area ratio of 5 mm−1 to 8 mm−1, is introduced in an ebullated bed reactor system to reduce sediment yield while maintaining high hydrodesulfurization and conversion activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydroprocessing processes are used for heavy hydrocarbon feedstocks, then hydrodesulfurization and conversion activity are achieved, but sediment formation increases
Solution Approach 1:
The patent applies parameter changes by modifying the catalyst particle characteristics including size (0.5-10 mm), shape (cylindrical, spherical, polylobal), and pore size distribution to optimize the balance between conversion activity and sediment reduction. The specific geometric parameters and pore structure are tuned to achieve high desulfurization while minimizing asphaltene precipitation and sediment formation.
Solution Approach 2:
The patent employs composite catalyst materials consisting of metal components (such as nickel, molybdenum, or platinum) supported on alumina or silica-alumina carriers. This composite structure provides both the hydrodesulfurization activity from the metal and the controlled pore structure from the support, enabling simultaneous high conversion and low sediment yield.
2Object-generated harmful factors
If larger particle-size catalysts are used in ebullated bed reactors, then sediment formation is reduced, but conversion activity decreases
Solution Approach 1:
The patent resolves this contradiction by optimizing particle size parameters to a specific range (0.5-10 mm) and implementing specific pore size distributions within the catalyst structure. This allows smaller particles that maintain high conversion activity while the controlled pore structure and surface properties prevent excessive sediment formation, achieving both goals simultaneously rather than requiring larger particles that would reduce activity.
Solution Approach 2:
The patent applies local quality by creating different pore size distributions in different regions of the catalyst particle structure. The external surface and pore structures are specifically designed to control asphaltene interaction and minimize precipitation, while internal active sites maintain high conversion activity. This localized optimization allows small particles to achieve both low sediment and high conversion.
3Ease of manufacture
If standard catalyst shapes are used in ebullated bed reactors, then ease of manufacture is maintained, but sediment yield is not adequately controlled
Solution Approach 1:
The patent employs asymmetric and varied catalyst particle shapes including cylindrical, spherical, and polylobal forms with specific geometric parameters. These non-standard shapes provide improved fluidization characteristics and reduced sediment formation compared to conventional uniform shapes, while still being manufacturable through established ceramic shaping and extrusion techniques.
Solution Approach 2:
The patent controls sediment yield through specific geometric parameters of the catalyst particles including diameter (0.5-10 mm), length-to-diameter ratios, and surface area characteristics. These parameter optimizations are achieved through controlled manufacturing processes that can produce the required shapes and sizes while maintaining ease of production through standard ceramic and metallurgical techniques.
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
This approach significantly reduces sediment yield in the heavy hydrocarbon conversion product to less than 0.5 wt.%, achieving high desulfurization and conversion efficiency without negatively impacting kinetic parameters or conversions.
Implementation Method 1
The ebullated bed reaction zone comprises a catalyst bed of small particle size, shaped hydroprocessing catalyst particles, which comprise a calcined shaped alumina support impregnated with at least one active catalytic metal component
Implementation Method 2
an ebullated bed reactor system for the hydroconversion of a heavy hydrocarbon feedstock
Data Source
AI summary
An ebullated bed process for the hydroconversion of heavy hydrocarbon feedstocks that provides for high conversion of the heavy hydrocarbon with a low sediment yield. The process uses for its catalyst bed an impregnated shaped ebullated bed catalyst having a low macroporosity and a geometry such that its characteristic cross section perimeter-to-cross sectional area is within a specifically defined range.