Hydrotreating Catalyst Preparation via Partial Organic Acid Oxidation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydrotreating catalysts are not sufficiently reactive and effective for removing heteroatoms like sulfur and nitrogen from hydrocarbon streams, necessitating the development of more advanced catalysts for improved hydrodesulfurization and hydrodenitrogenation processes.
Innovation Solution
A method involving the preparation of a catalyst composition with a partially oxidized metal-organic component, achieved by impregnating an inorganic support with Group VIB and Group VIII metal salts and an organic acid, followed by calcination and sulfiding, resulting in a catalyst with a high carbon-as-carboxyl to total carbon ratio, enhancing the catalyst's activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrotreating catalysts are used, then the catalyst structure is simple and easy to manufacture, but the catalyst activity for removing heteroatoms is insufficient
Solution Approach 1:
The patent applies preliminary action by performing a controlled calcination treatment before the final sulfiding step. The catalyst precursor is calcined at 350-500°C in an oxygen-containing atmosphere to partially oxidize the organic acid and create carboxyl groups on the support surface, while preserving some organic content. This preliminary oxidation step enhances the catalyst's hydrodesulfurization and hydrodenitrogenation activity by creating favorable surface chemistry conditions before the active metal sulfides are formed.
Solution Approach 2:
The patent employs parameter changes by controlling the calcination temperature (350-500°C) and atmosphere (oxygen-containing) to achieve partial oxidation of the organic acid. This controlled thermal treatment transforms the organic component from a simple structureless carbon to a partially oxidized state with carboxyl groups, as evidenced by the Ccarboxy/Ctotal ratio of at least 0.10. This parameter control creates the optimal surface chemistry for enhanced catalyst activity without complete decomposition of the organic acid.
2Reliability
If the organic acid is completely decomposed during calcination, then the catalyst structure is stable, but the catalyst activity is reduced
Solution Approach 1:
The patent applies partial action by performing controlled calcination that oxidizes only a portion of the organic acid component. The calcination conditions (350-500°C in oxygen-containing atmosphere) are specifically designed to achieve partial oxidation, resulting in a loss-on-ignition of 1-20 wt.% and a Ccarboxy/Ctotal ratio of at least 0.10. This partial oxidation creates carboxyl groups on the support surface that enhance catalyst activity while maintaining structural stability, avoiding complete decomposition of the organic acid.
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 resulting catalyst demonstrates improved hydrodesulfurization and hydrodenitrogenation activity, effectively reducing sulfur and nitrogen levels in hydrocarbon feedstocks, meeting stringent regulatory and operational requirements.
Implementation Method 1
impregnating an inorganic catalyst support with an aqueous solution containing (i) a salt of a Group VIB metal selected from Mo and W, (ii) a salt of a Group VIII metal selected from Co and Ni, and (iii) an organic acid
Implementation Method 2
calcining the dried catalyst precursor in an oxygen-containing atmosphere for a time and temperature sufficient to oxidize some but not all of the organic portion of the metal-organic component
Implementation Method 3
calcining the dried catalyst precursor in an oxygen-containing atmosphere for a time and temperature sufficient to oxidize some but not all of the organic portion
Implementation Method 4
sulfiding the partially oxidized catalyst precursor at sulfiding conditions in the presence of a sulfiding agent, thereby resulting in a sulfided catalyst composition
Data Source
AI summary
This disclosure relates to supported multi-metallic catalysts for use in the hydrotreating of hydrocarbon feeds, as well as a method for preparing such catalysts. The catalysts are prepared from a catalyst precursor comprised of at least one Group VIB metal, at least one Group VIII metal and an organic acid. The catalyst precursor is thermally treated to partially decompose the organic acid, then sulfided. The catalysts have a high carbon-as-carboxyl to total carbon ratio (Ccarboxy/Ctotal) as a result of a unique post-metal calcination method employed during the manufacture of the catalyst.