Base Metal Catalyst for PTA Emissions Using Oxygen-Donating Support
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Solution Overview
Problem
Current catalysts for treating emissions from the purified terephthalic acid (PTA) process, particularly those based on precious metals, are expensive and inefficient for removing carbon monoxide (CO), volatile organic compounds (VOCs), and methyl bromide, due to the high cost of noble metals and the poisoning effect of methyl bromide on common catalysts.
Innovation Solution
A base metal catalyst system comprising copper (Cu) and manganese (Mn) supported on an oxygen-donating support material, such as ceria, that is substantially free of alumina, effectively oxidizes CO, VOCs, and methyl bromide, utilizing the oxygen-donating properties of the support to enhance catalytic activity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precious metal catalysts (Pt, Pd, Rh) are used for catalytic oxidation, then oxidation effectiveness is improved, but catalyst cost increases significantly
Solution Approach 1:
The patent replaces expensive precious metals with base metals (Cu, Mn, Fe, Co, Ni, Zn) that are abundant and much less costly. The catalyst system uses base metal oxides supported on alumina or silica, providing an economical alternative to Pt, Pd, and Rh while maintaining catalytic oxidation effectiveness for CO and VOC removal.
Solution Approach 2:
The patent modifies the catalyst composition by changing the metal type from precious to base metals, and optimizes the oxidation state (e.g., CuO, Mn2O3, Fe2O3) and support material (alumina, silica) to achieve effective catalysis at lower costs. The catalyst may also be modified with promoters to enhance activity and resistance to poisoning.
2Ease of manufacture
If common catalysts are used for oxidation, then catalyst cost is reduced, but catalyst performance deteriorates due to methyl bromide poisoning
Solution Approach 1:
The patent addresses the harmful effect of methyl bromide poisoning by using base metal catalysts with specific compositions (CuO-Mn2O3, CuO-Fe2O3, etc.) that are resistant to halogenated hydrocarbon deactivation. The catalyst system converts the challenge of methyl bromide presence into an opportunity to develop more robust, poisoning-resistant catalysts that maintain performance in PTA waste streams.
Solution Approach 2:
The patent employs composite catalyst systems combining multiple base metal oxides (e.g., CuO with Mn2O3, Fe2O3, CoO, NiO, or ZnO) supported on alumina or silica. This composite structure enhances both the anti-poisoning capability against methyl bromide and the overall catalytic oxidation effectiveness, overcoming the limitations of single-metal catalysts.
3Ease of manufacture
If base metal catalysts are used to reduce cost, then catalyst cost decreases, but oxidation effectiveness and stability worsen
Solution Approach 1:
The patent optimizes the oxidation state of base metals (using CuO, Mn2O3, Fe2O3, CoO, NiO, ZnO) and their ratios in the catalyst composition to enhance catalytic activity. The support material (alumina, silica) and promoter additions are carefully selected to improve stability and resistance to deactivation, ensuring that base metal catalysts achieve oxidation effectiveness comparable to or exceeding precious metal catalysts.
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 system achieves high conversion rates (>95%) of CO, VOCs, and methyl bromide at lower temperatures compared to commercial catalysts, demonstrating superior durability and longevity while maintaining stability in the presence of water vapor, thus providing an affordable and effective solution for PTA process emissions control.
Implementation Method 1
a first base metal catalyst comprising Cu in contact with an oxygen donating support... utilized the oxygen-donating properties of the support to enhance catalytic activity
Implementation Method 2
The catalyst comprises a first base metal catalyst comprising Cu... and at least one second base metal catalyst comprising Mn... effectively oxidizes CO, VOCs, and methyl bromide
Implementation Method 3
Across the catalyst, VOC and CO emissions are oxidized to CO2 and water, while methyl bromide is converted to CO2, water, and HBr/Br2
Data Source
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AI summary
A catalyst for oxidizing carbon monoxide (CO), volatile organic compounds (VOCs), and methyl bromide (CH3Br) is provided. The catalyst comprises a first base metal catalyst supported on an oxygen donating support that is substantially free of alumina, and at least one second base metal catalyst. Also provided is a method for treating the waste stream from a purified terephthalic acid (PTA) process, the method comprising contacting a waste stream containing carbon monoxide (CO), volatile organic compounds (VOCs), and methyl bromide with a catalyst comprising a first base metal catalyst supported on an oxygen donating support that is substantially free of alumina, and at least one second base metal catalyst.