Single-Step Calcination Sulfidation for CoMoS Catalyst Synthesis
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Solution Overview
Problem
Conventional hydrodesulfurization catalyst synthesis methods require additional sulfidation steps and pre-treatments, which can be incomplete due to metal-support interactions, and often result in catalysts with metals in oxide forms that need reduction and subsequent sulfidation, complicating the process.
Innovation Solution
A single-step calcination and sulfidation method is employed to produce CoMoS hydrodesulfurization catalysts by mixing molybdenum and cobalt precursors with mercaptoalkyltrialkoxysilane and a structural directing surfactant, followed by hydrothermal treatment and calcination in an activation gas, eliminating the need for separate sulfidation and reducing the complexity of the synthesis process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional multi-step synthesis methods are used, then metals can be deposited on support, but additional sulfidation and reduction steps are required, increasing process complexity
Solution Approach 1:
The patent combines calcination and sulfidation steps into a single simultaneous operation. By introducing sulfur-containing compounds (such as dimethyl disulfide or carbon disulfide) during the calcination process, the method achieves both oxide decomposition and metal sulfide formation in one step, eliminating the need for separate reduction and sulfidation steps that are required in conventional methods
Solution Approach 2:
The patent incorporates sulfur-containing compounds into the catalyst precursor mixture before calcination. This preliminary introduction of sulfur sources ensures that when calcination occurs, the sulfur is already positioned to react with metal oxides, preventing incomplete sulfidation and eliminating the need for subsequent sulfidation steps
2Manufacturing precision
If separate sulfidation step is performed, then metal sulfides can be formed, but the sulfidation is often incomplete due to metal-support interactions
Solution Approach 1:
The patent maintains continuous sulfur exposure during the entire calcination process by introducing sulfur-containing compounds that decompose and release sulfur throughout the heating cycle. This continuous sulfidation action ensures complete conversion of metal oxides to sulfides without the interruption or incompleteness that occurs in separate step methods where metal-support interactions can interfere
Solution Approach 2:
The patent modifies the calcination atmosphere by introducing sulfur-containing compounds (such as dimethyl disulfide, carbon disulfide, or hydrogen sulfide) at controlled concentrations. This parameter change transforms the calcination process from simple oxide decomposition to simultaneous sulfidation, ensuring complete and consistent metal sulfide formation while maintaining catalyst structural integrity
3Productivity
If conventional synthesis methods are used, then catalysts can be produced, but operational time and costs increase due to multiple steps
Solution Approach 1:
The patent merges multiple unit operations (calcination, reduction, and sulfidation) into a single integrated process step. By introducing sulfur-containing compounds during calcination, the method simultaneously achieves oxide decomposition, metal reduction, and sulfide formation, reducing the number of operational steps and associated time losses
Solution Approach 2:
The patent extracts the sulfidation function from the conventional multi-step sequence and integrates it into the calcination step itself. This eliminates the need for separate reduction and sulfidation operations, thereby reducing total operational time and processing costs while maintaining complete sulfide formation
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 method directly forms cobalt and molybdenum sulfide on mesoporous silica without additional sulfidation, enhancing metal dispersion and catalyst activity, reducing operational time and costs, and improving product yield by integrating sulfidation with calcination, resulting in efficient hydrodesulfurization of hydrocarbon feedstocks.
Implementation Method 1
mixing a molybdenum precursor, a cobalt precursor, a mercaptoalkyltrialkoxysilane, a structural directing surfactant, an acid, and a solvent to form a reaction mixture, (ii) hydrothermally treating the reaction mixture to form a dried mass
Implementation Method 2
mixing a molybdenum precursor, a cobalt precursor, a mercaptoalkyltrialkoxysilane, a structural directing surfactant, an acid, and a solvent to form a reaction mixture, (ii) hydrothermally treating the reaction mixture to form a dried mass
Implementation Method 3
calcining the dried mass in an activation gas, thereby forming the CoMoS hydrodesulfurization catalyst
Implementation Method 4
calcining the dried mass in an activation gas, thereby forming the CoMoS hydrodesulfurization catalyst... directly forms cobalt and molybdenum sulfide on mesoporous silica
Data Source
AI summary
A method of preparing hydrodesulfurization catalysts having cobalt and molybdenum sulfide deposited on a support material containing mesoporous silica. The method utilizes a sulfur-containing silane that dually functions as a silica source and a sulfur precursor. The method involves an one-pot strategy for hydrothermal treatment and a single-step calcination and sulfidation procedure. The application of the hydrodesulfurization catalysts in treating a hydrocarbon feedstock containing sulfur compounds to produce a desulfurized hydrocarbon stream is also specified.