Cobalt Fischer-Tropsch Catalyst Regeneration via High-Pressure Oxidation
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Solution Overview
Problem
Cobalt Fischer-Tropsch synthesis catalysts lose activity over time, leading to deactivation, and existing methods are ineffective in fully regenerating spent catalysts for reuse.
Innovation Solution
A process involving sequential dewaxing, oxidation at elevated pressures (4 to 30 bar(a)), and reduction treatments is employed to regenerate spent cobalt Fischer-Tropsch synthesis catalysts, with optional additional regeneration cycles, utilizing techniques like hydrogenolysis, solvent washing, and calcination in a fluidized bed at controlled temperatures and pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional regeneration methods are used on spent cobalt catalysts, then the catalyst can be partially restored, but the activity recovery is incomplete and the catalyst cannot be fully regenerated for reuse
Solution Approach 1:
The invention changes the pressure parameter from conventional atmospheric or low pressure to elevated pressure range of 4-30 bar(a) during oxidation treatment. This parameter change enables complete removal of residual carbon/wax deposits that conventional methods cannot eliminate, achieving full catalyst activity recovery
Solution Approach 2:
The invention implements a cyclic regeneration process with alternating oxidation and reduction treatments. The periodic application of oxidation (to remove carbon) followed by reduction (to restore metallic cobalt) enables complete regeneration that can be repeated multiple times on the same catalyst
2Ease of manufacture
If oxidation treatment is performed at atmospheric pressure, then the process is simpler, but residual carbon and wax deposits remain on the catalyst
Solution Approach 1:
The invention elevates the oxidation pressure to 4-30 bar(a), which fundamentally changes the oxidation efficiency and enables complete removal of carbon and wax deposits. This pressure parameter change transforms the oxidation process from incomplete at atmospheric pressure to complete at elevated pressure
3Duration of action of stationary object
If multiple regeneration cycles are implemented, then catalyst lifespan is extended, but the process complexity increases
Solution Approach 1:
The invention establishes a periodic regeneration cycle consisting of oxidation followed by reduction treatments. This cyclic approach allows the same catalyst to undergo multiple regeneration cycles, extending its operational life from single-use to reusable status
Solution Approach 2:
The invention includes a preliminary dewaxing treatment before the main oxidation-reduction cycle. This preliminary action removes bulk wax deposits, preparing the catalyst for more effective oxidation and enabling successful multiple regeneration cycles
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 process effectively recovers catalyst activity, allowing for nearly complete restoration of Fischer-Tropsch synthesis performance without negatively impacting methane selectivity, thereby improving process economics by extending catalyst lifespan.
Implementation Method 1
The oxidation treatment may comprise subjecting the dewaxed catalyst particles to calcination by fluidizing the catalyst particles in an oxygen containing gas at an elevated temperature and at the elevated pressure of from 4 to 30 bar(a), thereby to oxidize the catalyst particles
Implementation Method 2
calcination including heating the catalyst particles up to a temperature T and holding the catalyst particles at the temperature T for a period of time
Implementation Method 3
subjecting the dewaxed catalyst particles to calcination by fluidizing the catalyst particles in an oxygen containing gas
Implementation Method 4
The dewaxing treatment may include hydrogenolysis
Implementation Method 5
The dewaxing treatment may include solvent wash or extraction
Data Source
AI summary
A process for regenerating a spent cobalt Fischer-Tropsch synthesis catalyst includes subjecting a spent particulate cobalt Fischer-Tropsch synthesis catalyst sequentially to a dewaxing treatment, an oxidation treatment at a pressure of 4 to 30 bar(a) and a reduction treatment, thereby regenerating the catalyst.