Sulphided Catalyst for Hydrodeoxygenation Stability
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Solution Overview
Problem
Existing catalysts for hydrodeoxygenation of biologically derived oxygenate feedstocks face instability due to the lack of sulfur compounds, leading to reduced activity and selectivity, and require costly regeneration processes to remove carbonaceous deposits, which further complicates the process.
Innovation Solution
A catalyst composition with a porous alumina carrier of low acidity and wide pores, loaded with a combination of Group VIB and Group VIII metals, is used in the presence of hydrogen sulphide to maintain the sulphided state, reducing carbon deposition and enhancing stability and activity during hydrodeoxygenation of oxygenate feedstocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sulphided catalysts are used to achieve high hydrodeoxygenation activity, then catalytic activity is improved, but catalyst stability deteriorates due to breakdown to oxide forms
Solution Approach 1:
The catalyst is pre-sulphided before use in hydrodeoxygenation to establish the active sulphided state. This preliminary action ensures the catalyst achieves high activity while the continuous presence of H2S maintains this state, preventing breakdown to inactive oxide forms during operation.
Solution Approach 2:
The chemical environment is modified by introducing hydrogen sulphide (H2S) into the reaction system. This parameter change maintains the catalyst in its sulphided state through dynamic equilibrium, preserving both high catalytic activity and stability during the hydrodeoxygenation process.
2Productivity
If catalysts are continuously regenerated by combustion to remove carbonaceous deposits, then catalytic efficiency is restored, but process complexity and energy consumption increase
Solution Approach 1:
The carbonaceous deposits that normally require combustion removal are converted into beneficial carbon disulphide (CS2) through reaction with H2S. This transforms a harmful deactivating agent into a useful sulphurizing agent that maintains catalyst activity, eliminating the need for separate regeneration operations.
Solution Approach 2:
The catalyst performs self-regeneration by reacting with H2S in the reaction environment. The sulphur from H2S reacts with carbon deposits to form CS2, which desorbs and leaves the catalyst surface clean and active, enabling continuous operation without external regeneration systems.
3Device complexity
If metal loading is reduced to simplify the process, then catalyst complexity decreases, but catalytic activity deteriorates
Solution Approach 1:
The chemical environment is changed by introducing H2S, which fundamentally alters the catalyst's active state and enhances its intrinsic activity. This parameter change allows lower metal loadings to achieve the same productivity, reducing catalyst complexity while maintaining performance.
Solution Approach 2:
The catalyst combines Group VIB metals (Mo, W) with Group VIII metals (Ni, Co) on an alumina support to create a composite material with synergistic effects. This composite structure enhances catalytic activity per unit metal, allowing reduced metal loading while maintaining high productivity.
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 achieves high hydrodeoxygenation activity with reduced carbon deposition, maintaining efficiency and selectivity, and allows for lower metal loading without sacrificing activity, thus simplifying the process and reducing energetic costs.
Implementation Method 1
a porous carrier substantially comprised of alumina, said carrier comprising between 0 to 1 wt.% phosphorous and between 0 to 1 wt. % silicon, both calculated as oxides, and having a mean pore diameter in the range from 5 nm to 40 nm
Implementation Method 2
contacting said feedstock with a sulphided catalyst composition under hydrodeoxygenation conditions, under addition of hydrogen sulphide or precursors thereof such that the hydrogen sulphide is present in the hydrogen gas in an amount between 10ppm and 10000 ppm
Implementation Method 3
a catalyst composition comprising: i) a porous carrier substantially comprised of alumina... and, ii) from 1 to 20 wt. % of an active metal component, calculated as oxides based on the weight of the composition, borne on said porous carrier and which comprises at least one Group VIB metal and at least one Group VIII metal
Data Source
Figure 1
AI summary
A method for the hydrodeoxygenation of an oxygenate feedstock comprising contacting said feedstock with a sulphided catalyst composition under hydrodeoxygenation conditions, wherein said catalyst composition comprises: i) a porous carrier substantially comprised of alumina, said carrier comprising between 0 and 1 wt.% phosphorous and between 0 and 1 wt. % silicon (both calculated as oxides) and having a mean pore diameter in the range from 5 nm to 40 nm; and, ii) from 1 to 20 wt. % of an active metal component (calculated as oxides based on the weight of the composition) borne on said porous carrier and which comprises at least one Group VIB metal and at least one Group VIII metal.