Hydrotreating Catalyst Segmentation for Metal Accommodation
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Solution Overview
Problem
Heavy raw oils contain metal impurities and large molecule substances that cause catalyst deactivation and product quality issues due to metal depositing and coking, necessitating improved hydrogenation conversion and metal accommodation capabilities.
Innovation Solution
A catalyst combination comprising hydrogenation protection, demetalling, and treatment catalysts with specific alumina supports and metal elements, optimized for pore structure and metal content, is used for hydrotreating heavy raw oils, enhancing both asphaltine conversion and metal accommodation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrogenation catalysts are used for heavy raw oils, then the process can proceed, but metal impurities cause catalyst deactivation and coking, reducing operation period and product quality
Solution Approach 1:
The catalyst system is divided into multiple functional segments: a protection catalyst layer that removes metal impurities first, followed by a main hydrogenation catalyst layer. This segmentation prevents metal poisoning of the main catalyst, maintaining its activity and extending the operation period without frequent regeneration.
Solution Approach 2:
The protection catalyst acts as an intermediary between the heavy raw oil feed and the main hydrogenation catalyst. It selectively removes metal impurities (Ni, V, Fe, Ca) and converts them into removable forms, protecting the main catalyst from deactivation while allowing the hydrogenation process to proceed efficiently.
2Productivity
If hydrogenation conditions are intensified to improve asphaltine conversion, then conversion efficiency increases, but metal deposition and catalyst coking worsen
Solution Approach 1:
The protection catalyst performs preliminary removal of metal impurities and conversion of problematic substances before the oil reaches the main hydrogenation catalyst. This preliminary action prevents metal deposition and coking on the main catalyst, allowing intensified hydrogenation conditions to be applied without the usual penalties.
Solution Approach 2:
The protection catalyst converts harmful metal impurities and intractable substances into beneficial forms that can be easily removed or that improve the overall process. Metal impurities are converted into removable complexes, and some intractable large molecules are converted into more manageable species, turning potential catalyst poisons into process benefits.
3Quantity of substance
If catalyst pore structure is optimized for metal accommodation, then metal removal improves, but hydrogenation activity may be reduced
Solution Approach 1:
The catalyst system segments the functions of metal accommodation and hydrogenation activity into different layers. The protection catalyst layer has optimized pore structure for metal accommodation, while the main hydrogenation catalyst layer has optimized structure for hydrogenation activity. This segmentation allows both functions to be optimized independently without compromising either.
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 combination effectively prolongs catalyst life, improves product quality by maintaining high hydrogenation activity and reducing metal deposition, thereby extending operation periods and enhancing the quality of hydrotreated heavy raw oils.
Implementation Method 1
A catalyst combination for hydrotreating raw oils such as heavy raw oils, and a process for hydrotreating raw oils such as heavy raw oils
Implementation Method 2
the support has a pore volume measured by the mercury porosimetry of 0.94.2 mL/g, preferably 0.95-1.15 mL/g; the support has a specific surface area of 50-300 m2/g, preferably 80-200 m2/g
Data Source
AI summary
The present invention relates to a catalyst combination for hydrotreating raw oils and a process for hydrotreating raw oils with the catalyst combination. The catalyst combination comprisesone or both of at least one hydrogenation protection catalyst I and at least one hydrogenation demetalling catalyst I;at least one hydrogenation demetalling catalyst II; andat least one hydrogenation treatment catalyst III.