Molten Salt Layer for Carbon Separation in Metal Pyrolysis
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Solution Overview
Problem
Conventional molten metal pyrolysis methods face challenges in efficiently separating solid carbon from molten metal, leading to reactor blockages and catalyst deactivation, with existing solutions either incomplete or ineffective in addressing carbon-metal interaction.
Innovation Solution
The use of a layer of immiscible molten salt with lower density than the molten metal to physically separate solid carbon, allowing it to accumulate on top and be collected with the salt, facilitating easy separation and maintaining the catalytic activity of the molten metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solid carbon accumulates on top of molten metal during pyrolysis, then carbon separation is simplified by density difference, but reactor blockage and catalyst deactivation occur
Solution Approach 1:
A molten salt layer is introduced as an intermediary substance between the molten metal catalyst and the solid carbon product. The salt layer accepts and accumulates carbon particles, preventing direct carbon-metal interaction and avoiding reactor blockage, while allowing continuous operation. The salt acts as a mediator that temporarily holds the carbon product.
Solution Approach 2:
The system is segmented into distinct layers: the molten metal catalyst layer at the bottom, the molten salt intermediate layer in the middle, and the solid carbon accumulation zone at the top. This segmentation separates the catalytic function from the product accumulation function, allowing independent optimization of each zone.
2Quantity of substance
If mechanical skimming is used to remove carbon from molten metal, then carbon removal is achieved, but molten metal is simultaneously removed causing catalyst depletion
Solution Approach 1:
The molten salt serves as an intermediary that selectively accumulates carbon without requiring removal of the underlying molten metal catalyst. Carbon particles are transferred to the salt layer, which can then be separately removed, leaving the metal catalyst intact and reusable.
Solution Approach 2:
The removal process is localized to the salt layer rather than affecting the entire molten metal system. Only the carbon-containing salt layer needs to be removed and replaced, while the bulk molten metal catalyst remains in place and continues functioning.
3Quantity of substance
If gas flow is used to blow carbon away from molten metal, then carbon removal is facilitated, but carbon-metal interaction is not addressed
Solution Approach 1:
The molten salt layer acts as a physical barrier and intermediary that prevents direct contact between carbon and molten metal. Carbon particles are captured by the salt layer before they can interact with or deactivate the metal catalyst, eliminating the harmful carbon-metal interaction.
4Object-generated harmful factors
If vitreous layer is used to cover molten metal, then carbon oxidation is promoted, but solid carbon product is lost and additional catalyst layer is required
Solution Approach 1:
The system controls the chemical parameters of the intermediate layer by selecting molten salts with specific properties - they are chemically inert toward carbon, have appropriate density and viscosity, and maintain liquid state at operating temperatures. These parameter changes prevent unwanted oxidation while enabling effective carbon separation.
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 method effectively prevents carbon-metal interaction, allows for complete carbon recovery without contaminating it with metal, and maintains the catalytic activity of the molten metal, enhancing the efficiency and quality of hydrogen and carbon production.
Implementation Method 1
The molten salt is immiscible with the molten metal. It has a lower density, and can therefore form a layer on top of the molten metal. The solid carbon product has an even lower density and can thus accumulate on top of the molten salt
Implementation Method 2
The molten salt is immiscible with the molten metal
Implementation Method 3
The solid carbon product has an even lower density and can thus accumulate on top of the molten salt
Implementation Method 4
Separation of the carbon product from molten salt is readily achieved, e.g. by simple washing with water, which rapidly removes salt from the carbon product
Data Source
AI summary
The present invention relates to a method for molten metal pyrolysis of hydrocarbons to produce hydrogen gas and carbon. Liquid salt is used to separate produced carbon from the molten metal and to facilitate isolation of produced carbon.