Cobalt-Manganese Fischer-Tropsch Catalysts for Higher Alcohol Selectivity
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Solution Overview
Problem
Existing Fischer-Tropsch processes produce alcohols as a side product in low yield, and there is a need to improve the activity and selectivity for producing increased amounts of alcohols.
Innovation Solution
A process involving a supported cobalt-manganese Fischer-Tropsch synthesis catalyst, with a specific weight ratio of manganese to cobalt and the use of an olefin co-feed, is employed to convert a mixture of hydrogen and carbon oxide into a product composition comprising alcohols and liquid hydrocarbons, enhancing alcohol selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional Fischer-Tropsch catalysts are used, then hydrocarbon production is maintained, but alcohol selectivity remains low
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by incorporating manganese oxide as a promoter with specific weight ratios (0.05-2.0 Co:Mn), and adjusts process parameters including adding olefin co-feed (0.001-40 wt% relative to total hydrogen, carbon oxide and olefin). These parameter changes transform the catalyst's selectivity from primarily producing hydrocarbons to producing increased amounts of alcohols while maintaining hydrocarbon production.
2Productivity
If catalyst focus is on C5+ hydrocarbon production, then fuel yield is improved, but alcohol production remains a side product in low yield
Solution Approach 1:
The patent creates a composite catalyst material combining cobalt (active metal), manganese oxide (promoter), and support materials (alumina, silica, or carbon). This composite structure synergistically enhances both hydrocarbon and alcohol production, with manganese oxide specifically promoting alcohol formation while cobalt maintains hydrocarbon synthesis activity. The composite material achieves dual productivity for both hydrocarbons and alcohols.
Solution Approach 2:
The olefin co-feed acts as an intermediary substance that mediates the reaction pathway to enhance alcohol production. The olefin (C2-C14) interacts with the catalyst surface and synthesis gas to facilitate alcohol formation through chain growth and oxygenation reactions, thereby increasing alcohol yield without compromising the primary hydrocarbon production function.
3Manufacturing precision
If manganese to cobalt weight ratio is increased, then alcohol selectivity is enhanced, but catalyst composition complexity increases
Solution Approach 1:
The patent optimizes the manganese to cobalt weight ratio within a specific range (0.05-2.0) to achieve effective alcohol selectivity enhancement without excessive complexity. This parameter optimization balances the promotional effect of manganese oxide on alcohol formation with the structural simplicity and manufacturing feasibility of the catalyst, avoiding overly complex compositions while maintaining high selectivity.
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 process achieves increased alcohol selectivity and productivity, producing alcohols in excess of the added olefin amount, with the catalyst exhibiting high selectivity for alcohols and olefins, particularly linear alpha alcohols and olefins.
Implementation Method 1
converting a mixture of hydrogen and carbon oxide into a product composition comprising alcohols and liquid hydrocarbons via a Fischer-Tropsch synthesis reaction
Implementation Method 2
contacting a mixture of hydrogen and the gaseous carbon oxide and an olefin co-feed with a supported cobalt-manganese Fischer-Tropsch synthesis catalyst
Data Source
AI summary
The present disclosure relates generally to compositions and processes for producing Fischer-Tropsch catalysts. In particular, the disclosure provides for a process for producing a product composition comprising alcohols and liquid hydrocarbons via a Fischer-Tropsch synthesis reaction, the process comprising: contacting a mixture of hydrogen and a gaseous carbon oxide that is carbon monoxide, carbon dioxide or a combination thereof and an olefin co-feed with a supported cobalt-manganese Fischer-Tropsch synthesis catalyst to provide the product composition; wherein the olefin co-feed comprises at least one C2-C14 olefin and is present in an amount in the range of 0.001 wt % to 40 wt % relative to the total amount of hydrogen, the gaseous carbon oxide and olefin; wherein a weight ratio of manganese to cobalt in the catalyst is at least 0.05 on an elemental basis.