Cobalt Catalyst Activity Maintenance via Titanium Chelate Support
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Solution Overview
Problem
Catalysts comprising cobalt on titania and cobalt aluminate supports face challenges in maintaining activity over time during hydrocarbon synthesis processes like the Fischer-Tropsch process, particularly in slurry bubble column reactors.
Innovation Solution
Incorporating a minor amount of TiO2 derived from a titanium chelate into the catalyst support, either before or during loading of catalytic metals, enhances activity maintenance by forming a catalyst with a major amount of titania and a minor amount of cobalt aluminate, improving the cobalt/aluminum ratio and support structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cobalt is supported on titania and cobalt aluminate supports for hydrocarbon synthesis, then catalytic activity is achieved, but activity maintenance deteriorates over time
Solution Approach 1:
The patent modifies the chemical composition parameters of the catalyst support by incorporating TiO2 derived from titanium chelate at specific concentrations (0.1-5 wt%). This parameter change in the support composition improves the cobalt/aluminum ratio and stabilizes the catalyst structure, thereby maintaining activity over extended periods without sacrificing initial catalytic performance
Solution Approach 2:
The patent creates a composite catalyst support system combining titania, cobalt aluminate, and TiO2 derived from titanium chelate. This composite structure leverages the synergistic effects of different materials: titania provides the base support structure, cobalt aluminate enhances catalytic activity, and the TiO2 from titanium chelate stabilizes the overall structure, resulting in improved activity maintenance and longevity
2Reliability
If TiO2 is added to improve activity maintenance, then catalyst stability improves, but manufacturing complexity increases
Solution Approach 1:
The patent employs titanium chelate as a precursor that is applied to the support before the final calcination step. The titanium chelate pre-loads the support structure with titanium in a controlled manner, and subsequent calcination converts it to TiO2 in-situ. This preliminary action simplifies manufacturing by avoiding separate TiO2 addition steps and ensures uniform distribution of TiO2 throughout the support matrix
Solution Approach 2:
The titanium chelate serves as an intermediary substance that facilitates the incorporation of TiO2 into the catalyst support. Instead of directly adding TiO2 powder (which would be difficult to distribute uniformly), the patent uses the titanium chelate as a soluble precursor that can be impregnated into the support structure, then converted to TiO2 through calcination. This intermediary approach simplifies the manufacturing process while achieving uniform TiO2 distribution
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 addition of TiO2 from a titanium chelate significantly improves the stability and activity maintenance of cobalt-based catalysts, leading to increased selectivity and longevity in hydrocarbon synthesis, as demonstrated by extended run tests showing reduced deactivation rates and higher hydrocarbon yields.
Implementation Method 1
calcining the so treated support at a temperature above about 250° C. whereby TiO2 is formed from the titanium chelate
Data Source
AI summary
The present invention provides a catalyst comprising a catalytic metal, preferably cobalt, rhenium or mixtures thereof. The catalytic metal is supported on a support comprising a major amount of titania and a minor amount of cobalt aluminate derived from anatase titania. The support also includes a minor amount of titania derived from a titanium chelate.