Fischer-Tropsch Catalyst Support Composite Stability
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Solution Overview
Problem
Fischer-Tropsch synthesis catalysts face challenges with hydrothermal and mechanical attrition in slurry reactors, leading to reduced performance and clogging issues due to the formation of fines and chemical alteration by water, which affects alumina-based catalysts.
Innovation Solution
A catalyst comprising alumina, silica, phosphorus, and spinel, with a specific composition and preparation process that enhances hydrothermal and mechanical resistance, allowing for improved catalytic performance across various support surface areas and pore distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If alumina-based catalysts are used in slurry reactors, then catalytic activity is achieved, but mechanical attrition and hydrothermal degradation occur leading to fines formation
Solution Approach 1:
The patent applies composite materials by combining alumina with silica, spinel, and phosphorus to create a multi-component support structure. This composite approach allows the catalyst to maintain catalytic activity from alumina while gaining mechanical strength from spinel and silica, and hydrothermal stability from phosphorus, thereby resolving the contradiction between activity and stability
Solution Approach 2:
The patent modifies the chemical composition parameters of the support by incorporating specific ratios of silica (5-30 wt%), spinel (10-40 wt%), and phosphorus (1-5 wt%). These parameter changes transform the support properties to achieve both high catalytic activity and resistance to mechanical attrition and hydrothermal degradation simultaneously
2Productivity
If catalyst particles are subjected to high linear speeds in slurry processes, then reaction efficiency is improved, but particle fragmentation increases leading to fines formation
Solution Approach 1:
The patent applies beforehand cushioning by incorporating spinel and phosphorus into the support structure prior to catalyst deployment. These components act as a pre-established protective framework that cushions the alumina structure against mechanical shocks and hydrodynamic stresses during high-speed slurry operation, preventing particle fragmentation before it occurs
3Productivity
If water is present during Fischer-Tropsch synthesis, then reaction proceeds as designed, but alumina undergoes chemical alteration reducing catalyst performance
Solution Approach 1:
The patent applies intermediary by introducing phosphorus as a mediating substance between water and alumina. Phosphorus forms a protective interface layer that allows water to be present for the Fischer-Tropsch reaction while preventing direct contact and chemical alteration of the alumina structure, thus maintaining both reaction proceeds and composition stability
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 exhibits superior hydrothermal and mechanical resistance, maintaining long-term catalytic activity and performance even with aluminas of lower specific surface areas, reducing fines formation and enhancing stability in harsh reaction conditions.
Implementation Method 1
the catalyst is subjected to particularly severe conditions in terms of mechanical and chemical stress... the solid works in advanced hydrothermal conditions... the alumina is partially transformed into boehmite, which weakens the catalyst from a mechanical point of view
Implementation Method 2
the very high linear speeds encountered in 'slurry' processes generate shocks between particles or against the walls of the equipment, shocks which can lead to the formation of fines
Implementation Method 3
Fischer-Tropsch synthesis processes make it possible to obtain a wide range of hydrocarbon cuts from the CO + H2 mixture... n CO + (2n+1) H2 → CnH2n+2 + n H2O
Data Source
AI summary
The present invention describes a catalyst containing an active phase comprising at least one metal from group VIIIB selected from cobalt, nickel, ruthenium, and iron, deposited on an oxide support comprising alumina, silica, spinel, and phosphorus. It also relates to the process for preparing said catalyst and its use in a Fischer-Tropsch process. The catalyst exhibits improved hydrothermal and mechanical resistance in a Fischer-Tropsch process while simultaneously enhancing its catalytic performance.