Fischer-Tropsch Catalyst Reprocessing via Supercritical De-waxing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fischer-Tropsch catalysts become deactivated and form spinels during calcination, making them resistant to hydrometallurgical leaching and difficult to recycle, especially when containing expensive metals like cobalt and precious metals.
Innovation Solution
A process involving de-waxing with a pressurized near-critical or supercritical fluid to minimize spinel formation, followed by hydrometallurgical leaching without calcination, allowing for the separation and recovery of catalyst metals from the support material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If calcination is performed at high temperatures to remove organic content, then residual organic content is reduced to acceptable levels, but catalyst metal-support spinel formation occurs making the catalyst resistant to hydrometallurgical leaching
Solution Approach 1:
The patent changes the fundamental parameter of organic removal from thermal decomposition (calcination) to solvent extraction (supercritical fluid de-waxing). This parameter change allows removal of organic content without reaching temperatures that cause spinel formation, thus resolving the contradiction between organic content reduction and maintaining leachability
Solution Approach 2:
The patent replaces the thermal-mechanical system of calcination with a chemical-solvent system using supercritical fluids. This substitution achieves organic removal through dissolution rather than combustion, avoiding the high temperatures that create harmful spinel compounds while maintaining catalyst recoverability
2Productivity
If traditional combustion and calcination methods are used to de-wax the catalyst, then organic content is removed, but spinel formation occurs reducing catalyst metal recovery efficiency
Solution Approach 1:
The patent changes the de-waxing parameter from high-temperature thermal processing to supercritical fluid extraction at moderate temperatures and pressures. This parameter change maintains efficient organic removal while preserving catalyst metal recovery efficiency by preventing spinel formation
Solution Approach 2:
The patent introduces supercritical fluids as an intermediary medium to facilitate organic content removal. This intermediary enables de-waxing without direct thermal contact that would cause spinel formation, thus maintaining both de-waxing efficiency and catalyst metal recovery efficiency
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
Effectively recovers catalyst metals with higher efficiency and purity compared to traditional methods, reducing spinel formation and enhancing the recycling of valuable metals like cobalt and precious metals.
Implementation Method 1
The de-waxing step is performed using a pressurised near-critical or supercritical fluid, wherein near critical is at a pressure at or above 80% of the critical pressure and/or at a temperature at or above 80% of the critical temperature for that fluid
Implementation Method 2
subjecting the de-waxed catalyst to hydrometallurgical leaching or extraction to separate catalyst metal or metals from catalyst support material
Data Source
AI summary
A process for re-processing of a Fischer-Tropsch catalyst is described comprising the steps of; (i) de-waxing the Fischer-Tropsch catalyst, (ii) subjecting the de-waxed catalyst to hydrometallurgical leaching or extraction to separate catalyst metal or metals from catalyst support material, and (iii) recovering the separated catalyst metal or metals, wherein the de-waxing step is performed using a pressurised near-critical or supercritical fluid under conditions that minimise catalyst metal spinel formation.