Oxygen-Free Methane Conversion Reactor for Zero Coke Deposition
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Solution Overview
Problem
Current methods for converting methane to ethylene are inefficient, often resulting in over-oxidation, carbon deposition, and low carbon atom utilization rates, which limits their industrial applicability.
Innovation Solution
A catalytic reactor configuration where active metal or non-metal components are lattice-doped onto the inner wall of a quartz or silica carbide reactor, creating a catalyst-reactor composite that enables efficient, oxygen-free conversion of methane to ethylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxidative coupling of methane is used to convert methane to ethylene, then ethylene can be produced, but over-oxidation occurs resulting in CO2 and H2O formation and low carbon atom utilization efficiency
Solution Approach 1:
The invention extracts and eliminates oxygen from the reaction system, using oxygen-free conditions to prevent over-oxidation of methane and ethylene. This removes the harmful oxidation pathway that leads to CO2 and H2O formation, thereby improving carbon atom utilization efficiency while maintaining ethylene production capability.
Solution Approach 2:
The invention creates an inert oxygen-free atmosphere using nitrogen or other inert gases as the reaction medium. This inert environment prevents unwanted oxidation reactions, allowing methane to be converted to ethylene through coupling reactions without forming CO2 and H2O, thus resolving the contradiction between productivity and carbon atom utilization.
2Productivity
If traditional catalysts are used in oxygen-free conditions, then carbon deposition occurs on catalyst surface, but this deactivates the catalyst rapidly
Solution Approach 1:
The invention uses composite catalyst systems combining transition metals (Fe, Co, Ni, Cu, Zn) with alkaline earth metals (Ca, Sr, Ba) or rare earth metals (La, Ce, Pr, Nd). This composite structure synergistically promotes methane activation and coupling while suppressing carbon deposition, thereby maintaining both high productivity and long catalyst stability under oxygen-free conditions.
Solution Approach 2:
The invention optimizes reaction parameters including temperature (700-1100°C), pressure (0.1-5 MPa), and gas hourly space velocity to control the balance between methane conversion and carbon deposition. By carefully adjusting these parameters, the system achieves high methane conversion rates while minimizing catalyst deactivation through carbon buildup.
3Use of energy by moving object
If high temperature is used to activate C-H bond of methane, then methane activation can be achieved, but energy consumption increases and catalyst deactivation accelerates
Solution Approach 1:
The invention optimizes the reaction temperature to the range of 700-1100°C, which is sufficient to activate the strong C-H bonds of methane through the catalytic action of transition metals, while avoiding excessive energy consumption and catalyst deactivation that would occur at much higher temperatures. This parameter optimization resolves the contradiction between achieving methane activation and minimizing energy loss.
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 achieves high methane conversion rates, selective ethylene production, and zero carbon deposition, while also addressing issues of catalyst stability and scalability.
Implementation Method 1
direct synthesis of ethylene through oxygen-free catalysis of methane
Implementation Method 2
The bond energy of C-H bond is as high as 434 kJ/mol... activation of the C-H bond of methane
Data Source
Figure 1~3B
AI summary
The present invention relates to a catalytic reactor configuration, preparation and a method of direct synthesis of ethylene through oxygen-free catalysis of methane. The reactor configuration comprises an inlet section I, a preheating section II, a transition section III, a reaction section IV and an outlet section V; except for the preheating section II and the reaction section IV, the existence of the inlet section I, the transition section III and the outlet section V depends on reaction conditions; and the process realizes no coke deposition synthesis of methane and high selectivity synthesis of ethylene. In the present invention, the methane conversion rate is 20-90%; ethylene selectivity is 65-95%; propylene and butylene selectivity is 5-25%; aromatic hydrocarbon selectivity is 0-30%; and coke deposition is zero. The present invention has the characteristics of long life of catalysts (>1000 h), high stability of redox and hydrothermal conditions at high temperature (<1700°C), high conversion rate of methane, high selectivity of products, zero coke deposition, no scaleup of catalyst, small industrialization difficulty, easy separation of products, good process reproducibility, safe and reliable operation and the like, and has wide industrial application prospect.