Trilobal Catalyst for Low Sediment in Ebullated Bed Hydroconversion
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Solution Overview
Problem
Ebullated bed processes for hydroconversion of heavy hydrocarbon oils often result in significant sediment formation in the conversion products, which is undesirable and needs to be minimized.
Innovation Solution
The use of an ebullated bed reactor system with a catalyst bed composed of shaped hydroprocessing catalyst particles having a specific trilobal geometry, characterized by a cross section perimeter-to-cross sectional area ratio within the range of 5 mm^-1 to 8 mm^-1, which facilitates reduced sediment yield during the hydroprocessing of heavy hydrocarbon feedstocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydroprocessing catalysts are used in ebullated bed processes, then heavy hydrocarbon conversion occurs, but significant sediment formation results in the conversion products
Solution Approach 1:
The patent applies asymmetry by using trilobal-shaped catalyst particles instead of conventional spherical or cylindrical shapes. The trilobal geometry creates asymmetric flow patterns and pressure distributions that prevent sediment formation while maintaining high conversion rates. The three-lobed structure with rounded intersections provides unique fluid dynamics that keep the catalyst bed expanded and prevent sediment deposition.
Solution Approach 2:
The patent changes the geometric parameters of the catalyst particles, specifically the cross-sectional shape from conventional forms to trilobal geometry. This parameter change affects the fluid-catalyst interaction, creating favorable pressure gradients and flow patterns that reduce sediment yield while maintaining high hydrocarbon conversion efficiency.
2Productivity
If catalyst particles with high surface area are used to improve conversion, then reaction efficiency increases, but pressure drop across the bed increases
Solution Approach 1:
The patent uses trilobal-shaped particles with rounded intersections and curved surfaces instead of sharp edges or flat surfaces. This curvature reduces flow resistance and pressure drop while maintaining high surface area for catalytic activity. The rounded geometry allows smoother fluid flow around and through the catalyst bed.
Solution Approach 2:
The trilobal cross-section introduces dimensional complexity that optimizes both surface area and flow characteristics. The three-lobed structure creates a balance between maximizing catalytic surface area and minimizing flow resistance, achieving high reaction efficiency without excessive pressure drop.
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 achieves a high conversion of heavy hydrocarbon feedstocks with a low sediment yield, particularly effective in processing feedstocks with high pitch content, by allowing smaller hydrocarbon molecules easier access to catalytic sites and improving reaction product egress, thereby reducing sediment formation.
Implementation Method 1
the heavy hydrocarbon feed is introduced in an upflow direction at the bottom of a catalyst bed contained within an ebullated bed reaction zone in a manner so as to lift or expand the catalyst bed to thereby form a fluidized bed of the catalyst
Implementation Method 2
The present invention further relates to a process for treating heavy hydrocarbon oils containing large amounts of impurities such as sulfur, micro carbon residue (MCR), metals, nitrogen, and asphaltenes to effect hydrodesulfurization (HDS), hydrodemetallisation (HDM), hydrodenitrification (HDN), micro carbon residue reduction, asphaltene reduction, and/or conversion of heavy hydrocarbons to lighter products
Data Source
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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 small particles of a specifically defined shaped hydroprocessing catalyst which is contacted with the heavy hydrocarbon feedstock under hydroconversion conditions and yields a hydrocarbon conversion having a relatively low sediment content.