Molten Salt Catalyst for Methane Pyrolysis
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Solution Overview
Problem
Current methane pyrolysis processes face challenges in achieving high methane conversion while maintaining catalyst stability and controlling carbon morphology, with existing methods like fluidized bed-CVD reactors experiencing low conversion rates and reactor plugging due to carbon deposition.
Innovation Solution
A catalyst system using a molten salt with dispersed catalytically active metals like iron, molybdenum, and copper, operating at temperatures above 700°C to promote high methane conversion and control carbon morphology, preventing carbon deposition on reactor walls and enabling efficient separation of hydrogen and solid carbon products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fluidized bed-CVD reactor is used for methane pyrolysis, then catalyst can be employed to promote reaction, but methane conversion remains lower than 40%
Solution Approach 1:
The invention changes the physical state of the catalyst from solid to liquid (molten salt), fundamentally altering the reaction environment. This parameter change enables high methane conversion (70-90%) while maintaining catalyst stability, as the molten salt can be easily separated from carbon deposits through temperature control, allowing catalyst regeneration without complex procedures
Solution Approach 2:
The molten salt acts as an intermediary medium that facilitates methane decomposition. The catalyst metals are dispersed in the molten salt, which mediates the interaction between methane and catalyst, enabling high conversion while preventing direct catalyst deactivation by carbon deposition
2Productivity
If higher conversion rates are achieved in FB-CVD reactor, then methane conversion increases, but catalyst stability and life-time deteriorate
Solution Approach 1:
The invention utilizes phase transition of the catalyst from solid to liquid state (molten salt above its melting point). This phase transition enables the catalyst to operate at high temperatures for high conversion while allowing easy separation from solid carbon products, preventing catalyst deactivation and extending catalyst life-time through simple regeneration by cooling and filtering
3Productivity
If FB-CVD method is used, then catalyst can promote methane decomposition, but carbon deposition on reactor wall causes plugging
Solution Approach 1:
The molten salt serves as an intermediary that captures carbon deposits in solution, preventing direct deposition on reactor walls. The carbon dissolves or disperses in the molten salt medium, and can be removed together with the catalyst through cooling and filtration, eliminating the plugging problem while maintaining high decomposition rates
4Reliability
If catalyst separation and regeneration is performed frequently, then catalyst stability is maintained, but process complexity and cost increase
Solution Approach 1:
The invention uses phase transition (temperature change) to simplify catalyst separation and regeneration. By cooling the molten salt below its melting point, the catalyst solidifies and can be easily filtered from the liquid phase, providing a simple, low-cost regeneration process that maintains catalyst stability without complex equipment or procedures
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 system achieves high methane conversion rates up to 75-100% with controlled carbon morphology, reducing the need for costly separations and reactor maintenance, and produces high-purity hydrogen without carbon dioxide, facilitating easy separation and utilization of solid carbon products.
Implementation Method 1
a catalyst system, which is active in pyrolyzing methane at reaction temperatures above 700°C, comprising a molten salt... having dispersed therein one or more catalytically active forms of iron, molybdenum, manganese, nickel, cobalt, titanium, and copper
Implementation Method 2
Methane pyrolysis in a molten media offers superior heat management and temperature control. In addition, methane decomposition in a molten media prevents the deposition of solid carbon layers on the reactor wall
Data Source
AI summary
A catalyst system, which is active in pyrolyzing methane at reaction temperatures above 700°C, comprising a molten salt selected from the group consisting of the halides of alkali metals; the halides of alkaline earth metals; the halides of zinc, copper, manganese, cadmium, tin and iron; and mixtures thereof, the molten salt having dispersed therein one or more catalytically active forms of iron, molybdenum, manganese, nickel, cobalt, zinc, titanium, and copper in the form of finely divided elemental metals, metal oxides, metal carbides or mixtures thereof.