Continuous Metal Oxide Catalyst Preparation via Hydrolysis
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Solution Overview
Problem
Current methods for preparing metal oxides catalysts, such as precipitation and hydrothermal synthesis, generate significant waste and require harsh conditions, leading to environmental concerns and high production costs, particularly in Fischer-Tropsch Synthesis (FTS) processes.
Innovation Solution
A method integrating atmospheric precipitation and hydrothermal reaction methods to produce metal oxides and hydrates, utilizing nitric acid solutions and pressurized superheated water vapor to achieve continuous, enclosed, and zero-release production of FTS catalysts, recycling nitric acid and minimizing waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional precipitation method is used to prepare metal oxides catalysts, then the preparation process is simple and operable, but significant waste is generated and environmental concerns arise
Solution Approach 1:
The patent recycles the alkaline solution containing metal ions back into the precipitation process after appropriate treatment. The filtrate from the catalyst precipitation is reused as the alkaline solution for subsequent batches, transforming waste into a valuable resource and eliminating the need for fresh alkaline solution and extensive washing water
Solution Approach 2:
The patent converts the harmful waste stream into a beneficial resource by recycling the alkaline solution. The waste filtrate containing metal ions and alkaline components is transformed into a reusable reagent that maintains catalyst quality while reducing environmental impact and production costs
2Manufacturing precision
If hydrothermal synthesis method is used to prepare metal oxides, then high quality catalysts with controlled properties are obtained, but harsh conditions and sealed pressurized containers are required
Solution Approach 1:
The patent modifies the hydrothermal synthesis parameters by conducting the reaction at lower temperatures (60-100°C) and atmospheric pressure instead of the conventional high temperature and pressure conditions. This is achieved by controlling the pH and composition of the alkaline solution, allowing quality catalyst production with simpler equipment
Solution Approach 2:
The patent inverts the conventional hydrothermal approach by using atmospheric pressure conditions instead of sealed pressurized containers. The reaction is conducted in open or loosely sealed vessels, eliminating the need for complex pressure control systems while maintaining catalyst quality through optimized chemical parameters
3Ease of manufacture
If metal salt decomposition method is used to obtain metal oxides, then the process is straightforward, but high temperature heating is required which increases energy consumption
Solution Approach 1:
The patent replaces the thermal decomposition mechanism with a chemical precipitation mechanism. Instead of heating metal salts to high temperatures to decompose them into oxides, the process uses alkaline solution to precipitate metal hydroxides or carbonates that are then calcined at much lower temperatures, significantly reducing energy consumption
Solution Approach 2:
The patent changes the temperature parameter from high temperature decomposition (typically >500°C) to low temperature precipitation (60-100°C) followed by low temperature calcination. This parameter change dramatically reduces the energy input required while maintaining catalyst quality
4Productivity
If continuous production is implemented for catalyst preparation, then productivity increases, but waste management and environmental control become more challenging
Solution Approach 1:
The patent implements continuous production with integrated recycling where the alkaline solution circulates continuously through the system. The filtrate from each batch is immediately reused in the next batch without interruption, maintaining continuous productive action while eliminating waste accumulation
Solution Approach 2:
The patent incorporates feedback control by monitoring the composition of the recycled alkaline solution and adjusting the process parameters accordingly. The system automatically maintains optimal pH and composition levels in the recycled solution, ensuring consistent catalyst quality while managing the continuous recycling process
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
This approach reduces environmental impact, lowers production costs, and achieves high-quality, uniformly dispersed metal oxides catalysts suitable for FTS, with improved energy efficiency and no additional chemical reagents needed, enabling continuous and enclosed circulation of water and acidic gases.
Implementation Method 1
dissolving one or more kinds of metal materials in a nitric acid solution to produce a metal nitrate solution
Implementation Method 2
introducing pressurized superheated water vapor into a reactor to perform a hydrolysis reaction on the metal nitrate solution to produce a slurry containing hydrates of metal oxides precipitate
Implementation Method 3
introducing pressurized superheated water vapor into a reactor to perform a hydrolysis reaction
Implementation Method 4
the slurry is filtered to obtain the corresponding hydrates of metal oxides and a filtrate
Implementation Method 5
the hydrates of metal oxides are dried to obtain the corresponding hydrates of metal oxides and/or metal oxides
Implementation Method 6
the nitric acid solution is recycled and reused in the metal salt solution preparation step
Data Source
AI summary
A method for continuously preparing a metal oxides catalyst comprises the following steps: dissolving metal materials using nitric acid solution to produce a metal nitrate solution, and also to produce NOx and water vapor; hydrolyzing the metal nitrate solution by introducing pressurized superheated water vapor into the metal nitrate solution to obtain a slurry of the hydrates of metal oxides as well as acidic gas, the main components of the acidic gas are NO2, NO, O2 and water vapor; filtrating and drying the slurry to obtain the hydrates of metal oxides and/or metal oxides; and then utilizing the obtained hydrates of metal oxides and/or metal oxides as raw materials and preparing the metal oxides catalyst by the conventional method for preparing a catalyst. The NOx gas produced can be absorbed to produce nitric acid which can be reused. An apparatus used for preparing metal oxides comprises a metal salt solution preparation system, a metal salt solution hydrolysis system, a product preparation system and a nitric acid preparation and recycling use system. The method and the apparatus can achieve continuous production, enclosed circulation and zero release in the whole process and can reduce the cost of production.