Mixed Oxide Catalyst Composition Without Nitrate Waste
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Solution Overview
Problem
Existing methods for producing mixed oxide catalysts for hydrocarbon reforming generate significant nitrate-containing waste, leading to environmental emissions and high production costs, and the catalysts suffer from stability issues such as coke formation during use.
Innovation Solution
A nitrate-free process using water-insoluble metal salts, particularly carbonates, combined with an alumina source and an aqueous acid, followed by specific calcination and densification steps, including tableting, to produce a mixed oxide catalyst comprising lanthanum, aluminum, and cobalt with improved stability and activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water-soluble metal salts (nitrates) are used as starting materials for catalyst preparation, then the catalyst can be easily prepared by precipitation or solid mixing, but significant amounts of nitrate-containing waste are produced leading to environmental emissions and high production costs
Solution Approach 1:
The invention changes the chemical parameter of the starting materials from water-soluble nitrates to water-insoluble carbonates. This parameter change eliminates the formation of nitrate-containing waste while maintaining the catalyst preparation process. The carbonates react with aqueous acid during calcination to form the desired mixed oxide catalyst without generating harmful nitrate emissions.
Solution Approach 2:
The invention converts the previously harmful nitrate-containing waste stream into a beneficial process by using carbonate salts that decompose to release CO2 (a naturally occurring gas) instead of nitrate emissions. The carbonate decomposition during calcination actually contributes to the formation of the active catalyst phases while eliminating environmental harm.
2Ease of manufacture
If water-soluble metal salts are used in the solid mixing route, then catalyst preparation is simplified, but high amounts of NOx are formed in the off-gas during thermal oxidative treatment requiring extensive cleaning efforts
Solution Approach 1:
The invention changes the anion parameter of the starting materials from nitrate to carbonate. This eliminates NOx formation during thermal treatment since carbonates decompose to CO2 and oxides rather than forming nitrogen oxides. The off-gas cleaning system is thereby simplified as CO2 requires no special treatment compared to NOx.
3Productivity
If conventional catalysts are used for hydrocarbon reforming, then the process can proceed, but the catalysts suffer from stability issues such as coke formation during use
Solution Approach 1:
The invention uses a composite mixed oxide material containing multiple metal oxides (e.g., NiO, CoO, MnO, ZnO, CuO, CaO, MgO, Al2O3, SiO2, TiO2, Fe2O3) in specific combinations. This composite structure provides both high catalytic activity for reforming reactions and enhanced stability by preventing coke formation through synergistic effects among the different oxide components.
Solution Approach 2:
The invention creates local active sites with specific metal oxide combinations that are optimized for both activity and stability. The distributed metal oxide phases create different local environments within the catalyst structure, with some regions providing high activity and others providing stability and coke resistance.
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 process reduces environmental emissions, lowers production costs, and enhances catalyst stability with reduced coke formation, resulting in a more active and selective catalyst for hydrocarbon reforming to synthesis gas.
Implementation Method 1
Reforming of hydrocarbons to a synthesis gas is a known catalytic reaction, in which Ni- or Co-containing oxide-based catalysts are used
Implementation Method 2
The preparation of the catalyst is preferably achieved using nickel nitrate as starting material. Also, additional metals may be included in the preparation, disclosed are inter alia aluminum, lanthanum, and cobalt
Data Source
AI summary
A molding comprising a mixed oxide, wherein the mixed oxide comprises oxygen, lanthanum, aluminum, and cobalt, wherein in the mixed oxide, the weight ratio of cobalt relative to aluminum, calculated as elements, is at least 0.17:1. A preparation method by a dry route. Use of the molding as a catalyst for the reforming of hydrocarbons into a synthesis gas.