Coal Upgrading for Low-Ash Graphene Quantum Dot Production
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Solution Overview
Problem
Naturally-sourced coal, particularly low-rank coal, has undesirable properties such as low carbon concentration, high oxygen concentration, and high ash content, making it less suitable for energy generation and production of high-value materials like graphene films, and graphene quantum dots are difficult and expensive to produce.
Innovation Solution
A method involving cleaning coal with strong mineral acids to form a cleaned coal residue, followed by reacting it with oxidizable inorganic metallic agents or reducing agents to upgrade the coal, reducing ash and oxygen content and increasing carbon concentration, thereby forming upgraded coal suitable for producing graphene films and quantum dots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If naturally-sourced low-rank coal is used directly, then the process is simple and low-cost, but the coal has low carbon concentration, high oxygen concentration, and high ash content making it unsuitable for high-value material production
Solution Approach 1:
The patent applies preliminary action by performing acid cleaning and chemical treatment on coal before it is used for graphene production. The coal undergoes pre-treatment with acids (HCl, H2SO4, HNO3) to remove impurities and increase carbon concentration, creating a higher-quality feedstock that enables subsequent high-value material production
Solution Approach 2:
The patent changes key parameters of the coal through chemical treatment. The acid cleaning process modifies the coal's chemical composition by removing oxygen-containing functional groups and inorganic impurities, transforming low-rank coal into a material with higher carbon concentration and lower ash content, making it suitable for graphene production
2Reliability
If conventional methods are used to produce graphene films, then the production process is established, but the material remains extremely expensive due to difficulty in mass production
Solution Approach 1:
The patent changes the starting material parameters by using upgraded coal with higher carbon concentration and lower impurity content. This parameter change in the feedstock enables more efficient conversion to graphene during chemical vapor deposition, improving productivity while maintaining product quality
Solution Approach 2:
The patent converts the typically harmful high-ash, low-carbon coal into a beneficial feedstock through acid cleaning and chemical treatment. The harmful impurities are removed and the coal's carbon structure is enhanced, transforming waste material into a valuable precursor for graphene production
3Manufacturing precision
If graphene quantum dots are produced using traditional methods, then the product has desired optical properties, but the production is difficult and expensive
Solution Approach 1:
The patent applies preliminary action by pre-upgrading the coal to high carbon concentration before quantum dot synthesis. This pre-treatment reduces the complexity of subsequent processing steps and lowers production costs while maintaining the optical properties of the resulting quantum dots
4Manufacturing precision
If coal is cleaned using strong mineral acids, then ash content and oxygen concentration are reduced, but the process complexity and chemical usage increase
Solution Approach 1:
The patent uses parameter changes through controlled acid treatment to achieve the desired reduction in ash and oxygen content. By optimizing acid concentration, temperature, and treatment time, the process achieves high purification efficiency while managing process complexity
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 upgraded coal achieves a lower ash content, reduced oxygen concentration, and higher carbon concentration, enabling more efficient conversion to graphene films and quantum dots with improved quality and efficiency.
Implementation Method 1
reacting the cleaned coal residue with an oxidizable inorganic metallic agent
Implementation Method 2
reacting the cleaned coal residue with a reducing agent
Data Source
AI summary
Upgraded coal, method of forming the same, and graphene films and quantum dots made therefrom. A method of upgrading coal includes cleaning coal to form a cleaned coal residue. The method also includes (A) reacting the cleaned coal residue with an oxidizable inorganic metallic agent, or (B) reacting the cleaned coal residue with a reducing agent, or a combination thereof, to form the upgraded coal.