Hydroconversion Catalyst with Narrow Pore Alumina Support
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Solution Overview
Problem
Hydrotreating catalysts used for heavy hydrocarbon feedstocks face rapid decline in catalytic activity due to high sulfur and metal compound concentrations, requiring severe process conditions and struggling to convert heavy boiling fractions into lighter components effectively.
Innovation Solution
A catalyst composition featuring an alumina support material with a medium pore diameter of 100-140 Angstroms, narrow pore size distribution, and high pore volume, combined with Group VIB and Group VIII metal components, is used to enhance catalytic stability and activity for hydroconversion processes, particularly in ebullated bed reactor systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrotreating catalysts are used for heavy hydrocarbon feedstock, then sulfur and metal compounds can be removed, but catalytic activity declines rapidly due to high contaminant concentrations
Solution Approach 1:
The patent employs an alumina support material with specifically controlled pore structure (pore diameter of 100-140 Angstroms, pore volume of 0.75-1.0 cc/g) to provide a stable framework that maintains catalytic activity. The porous structure allows access to active sites while preventing rapid deactivation by the harmful contaminants present in heavy hydrocarbon feedstock.
Solution Approach 2:
The catalyst composition combines Group VIB metals (Mo, W, Cr) with Group VIII metals (Ni, Co, Fe) on the alumina support to create a composite catalyst system. This combination provides both hydrotreating activity and hydroconversion capability, enabling the catalyst to maintain high stability while processing heavy feedstocks with high contaminant loads.
2Reliability
If severe process conditions are used to treat heavy hydrocarbon feedstock, then contaminant removal is improved, but conversion of heavy boiling fractions to lighter components becomes more difficult
Solution Approach 1:
The patent modifies the catalyst composition parameters by incorporating specific metal combinations (Group VIB and Group VIII metals) and controlling support material properties (alumina with 100-140 Angstroms pore diameter), which enables the catalyst to function effectively at moderate temperatures (300-500°C) and pressures (50-200 atm), achieving both contaminant removal and hydroconversion without requiring excessively severe conditions.
3Reliability
If catalyst bulk density is increased to prevent carryover, then catalyst stability is improved, but bed expansion becomes difficult to achieve
Solution Approach 1:
The alumina support material with its controlled pore structure (pore diameter of 100-140 Angstroms, pore volume of 0.75-1.0 cc/g) provides an optimal balance between mechanical stability and fluid dynamics. This porous structure allows the catalyst bed to expand properly in ebullated bed reactors while maintaining sufficient bulk density to prevent catalyst carryover with the product stream.
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 significantly improves pitch conversion and stability, achieving higher than 60% pitch conversion and maintaining catalytic performance over time, outperforming comparative catalysts in hydroconversion of heavy hydrocarbon feedstocks.
Implementation Method 1
The catalytic hydrotreatment of hydrocarbon feedstock in order to remove therefrom impurities such as sulfur, nitrogen, and metal compounds is a commonly used process to improve or upgrade such hydrocarbon feedstock
Implementation Method 2
the hydrocarbon feedstock is contacted in the presence of hydrogen with a hydrotreating catalyst under process conditions that suitably provide for a treated hydrocarbon product
Data Source
AI summary
A method of hydroprocessing a heavy hydrocarbon feedstock using a hydroprocessing catalyst having specific properties making it effective in the hydroconversion of at least a portion of the heavy hydrocarbon feedstock to lighter hydrocarbons. The hydroprocessing catalyst comprises a Group VIB metal component (e.g., Cr, Mo, and W), a Group VIII metal component (e.g., Ni and Co) and, optionally, a potassium metal component that are supported on a support material comprising alumina. The alumina has novel physical properties that, in combination with the catalytic components, provide for the hydroprocessing catalyst. The hydroprocessing catalyst is particularly effective in the conversion of the heavy hydrocarbon feedstock. The alumina is characterized as having a high pore volume and a high surface area with a large proportion of the pore volume being present in the pores within a narrow pore diameter distribution about a narrowly defined range of median pore diameters. The support material preferably does not contain more than a small concentration of silica. The alumina component is preferably made by a specific method that provides for an alumina having the specific physical properties required for the hydroprocessing catalyst.