Asymmetric Electrode Plasma Reactor for Fluidized Bed Thermal Management

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Solution Overview

Problem

Existing fluidized bed catalytic reactors face challenges in maintaining temperature homogeneity and maximizing the volume of the catalytic zone bathed in cold plasma, especially for large reactors, due to limitations in dielectric barrier discharge technology that restrict the inter-electrode distance and plasma volume.

Innovation Solution

A fluidized bed catalytic reactor design incorporating a surface dielectric barrier discharge plasma generation device with asymmetrically mounted electrodes and a tubular configuration, allowing for the generation of a large area plasma independent of inter-electrode distance, and enabling fluid circulation for thermal management, thereby expanding the plasma-covered volume and improving reaction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If volume DBD plasma technology is used with large inter-electrode distance, then the plasma volume increases, but the voltage required to generate plasma increases excessively

Engineering Contradiction:
Improveplasma volumeVSAvoidvoltage required
Core Design Contradiction:
Volume of stationary objectVSUse of energy by stationary object

Solution Approach 1:

The invention transitions from volume plasma generation (three-dimensional space between electrodes) to surface plasma generation (two-dimensional plasma layer on dielectric surface). This dimensional reduction allows plasma to be generated at the surface of the dielectric element rather than filling the entire inter-electrode volume, enabling large plasma coverage area without requiring proportionally high voltages.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The plasma is generated locally at the surface of the dielectric element where the electric field is concentrated, rather than uniformly throughout the entire inter-electrode space. This localized plasma generation on the dielectric surface allows for efficient plasma production with lower voltages while still achieving large effective plasma volume through the fluidized bed configuration.

Inventive Principle:
Principle #3Local quality

2Strength

If the reactor wall is made of dielectric material with thick walls, then structural integrity is improved, but the plasma generation efficiency decreases due to increased voltage requirements

Engineering Contradiction:
Improvereactor wall strengthVSAvoidvoltage required
Core Design Contradiction:
StrengthVSUse of energy by stationary object

Solution Approach 1:

A separate dielectric element is introduced as an intermediary component specifically for plasma generation purposes. This dielectric element can be positioned close to the catalyst bed regardless of the reactor wall thickness, allowing plasma generation to proceed efficiently without being constrained by the structural requirements of the reactor wall. The dielectric element acts as a dedicated plasma generation interface between the electrodes and the catalytic zone.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If separate thermal management devices are added, then temperature control is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature controlVSAvoidreactor layout complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The thermal management function is merged with the plasma generation system by integrating heat exchange capabilities into the electrode structure. The electrodes are designed with internal channels or surfaces that allow fluid circulation for heat removal, combining two previously separate functions (plasma generation and thermal management) into a single integrated system, thereby reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electrode structure is designed to perform multiple functions simultaneously: generating plasma through dielectric barrier discharge and providing thermal management through integrated heat exchange. This multi-functional design eliminates the need for separate thermal management devices and reduces the overall complexity of the reactor layout while maintaining both plasma generation efficiency and temperature control.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design achieves a larger volume of the catalytic zone bathed in controlled cold plasma, enhancing reaction efficiency and eliminating the need for separate thermal management devices, resulting in a more compact and effective reactor layout.

Implementation Method 1

at least one device for generating plasma by dielectric barrier discharge housed in the catalytic bed, said device being capable of generating a plasma from the gas injected into the enclosure via the inlet pipe

Methodology Applied
Scientific EffectDielectric barrier discharge:

Implementation Method 2

The application of a plasma in the vicinity of a catalytic phase allows an improvement in the efficiency of the chemical reaction at a given temperature or allows the temperature of the reaction to be lowered for a given conversion rate

Methodology Applied
Scientific EffectCold plasma: Plasma

Implementation Method 3

The reactants injected in gaseous form with an appropriate speed onto the catalytic bed then cause the latter to present a fluidized phase, which allows high mass and heat transfers, as well as thermal homogeneity of the reaction zone

Methodology Applied
Scientific EffectFluidization: Fluidisation

Implementation Method 4

at least one of the first and second electrodes comprises a tube capable of being connected to a fluid circulation circuit

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3046665B1Fluidized bed catalytic reactor comprising a surface plasma generator
Publication Date: 2017.06.28 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3046665B1 patent drawingFigure 1~3B
  • EP3046665B1 patent drawingFigure 4~5

AI summary

A fluidized bed catalytic reactor (10) comprises a chamber (12) having gas inlet and outlet ducts (18, 20), a fluidized catalytic bed (24) housed within the chamber (12), and a dielectric-barrier discharge plasma-generating device (26) housed within the catalytic bed (24). The plasma-generating device (26) comprises a dielectric element (28) within the catalytic bed (24) that comprises first and second opposite faces, and first and second electrodes (30, 40) mounted asymmetrically respectively on the first and second faces of the dielectric element (28). At least one of the first and second electrodes (30, 40) comprises a tube capable of being connected to a fluid circulation circuit.