Fluidized Bed Methane Pyrolysis via Resistive Heating
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Solution Overview
Problem
Current methods for endothermic direct pyrolysis of methane in fluidized bed reactors rely on external heating devices, which are often fossil carbon-based and environmentally unfriendly. There is a need for a more sustainable and efficient heating solution that can achieve high temperatures without external heating sources.
Innovation Solution
The process involves using a fluidized bed reactor with at least two electrodes and a bed comprising electrically conductive particles and catalytic composition. The electrically conductive particles, such as silicon carbide and mixed oxides, make up at least 10 wt.% of the bed and have a resistivity ranging from 0.001 Ohm.cm to 500 Ohm.cm at 800°C. Heat is generated by passing an electric current through the fluidized bed, eliminating the need for external heating devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external heating devices using fossil carbon-based fuels are used, then high temperatures (500°C to 1200°C) can be achieved for endothermic methane pyrolysis, but environmental harm increases and energy efficiency decreases
Solution Approach 1:
The patent replaces external thermal heating systems (fossil fuel burners and heat exchangers) with direct electrical heating through resistive heating elements immersed in the fluidized bed. This substitution eliminates combustion emissions and improves energy efficiency by directly heating the reaction medium rather than heating reactor walls and transferring heat indirectly.
Solution Approach 2:
The heating system is integrated within the reactor itself through electrically conductive heating elements that generate heat directly in the reaction zone. The system serves its own heating needs without requiring external fossil fuel-based heating devices, making the process self-sufficient and environmentally friendly.
2Temperature
If external heating devices are used to maintain temperatures between 500°C to 1200°C, then the endothermic methane pyrolysis reaction can proceed, but energy efficiency deteriorates due to heat loss through reactor walls
Solution Approach 1:
The patent replaces indirect thermal heating through reactor walls with direct electrical resistive heating elements immersed in the fluidized bed. This eliminates the thermal gradient through reactor walls and minimizes heat loss to the environment, significantly improving energy efficiency.
Solution Approach 2:
Electrically conductive particles or heating elements serve as intermediaries that directly convert electrical energy to thermal energy within the reaction zone. This intermediary mechanism delivers heat exactly where needed (in the fluidized bed) without the losses associated with wall conduction and convection.
3Temperature
If fired heated reactors are used for steam methane reforming, then high temperatures can be achieved, but the process becomes less economical and environmentally friendly
Solution Approach 1:
The patent replaces fossil fuel-based fired heating systems with electrical resistive heating, eliminating the need for additional fuel consumption and reducing operational costs. This substitution improves process economy while maintaining the required high temperatures for methane reforming and pyrolysis reactions.
Solution Approach 2:
The patent changes the heating method from thermal (fired) to electrical, fundamentally altering the energy input parameter. This parameter change improves both the environmental profile and economic viability of the process by eliminating fossil fuel consumption and associated costs.
Data Source
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AI summary
The disclosure relates to a process to perform an endothermic methane pyrolysis reaction, said process comprising the steps of providing at least one fluidized bed reactor comprising at least two electrodes; and a bed comprising particles, wherein the particles are put in a fluidized state by passing upwardly through the said bed a fluid stream, to obtain a fluidized bed; heating the fluidized bed to a temperature ranging from 500°C to 1200°C to conduct the endothermic methane pyrolysis reaction; wherein the particles of the bed comprise electrically conductive particles and particles of a catalytic composition; wherein at least 10 wt.% of the particles are electrically conductive particles and have a resistivity ranging from 0.001 Ohm. cm to 500 Ohm. cm at 800°C and wherein the step of heating the fluidized bed is performed by passing an electric current through the fluidized bed.