Fuel Cell Combustor Air Flow Guidance

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Solution Overview

Problem

Conventional fuel cell systems inadequately address the mixing of air and reformed gas in the combustor and the heating of the reformer, leading to inefficiencies in electric power generation and increased manufacturing costs.

Innovation Solution

A fuel cell system configuration that includes a reformer, solid-oxide fuel cells, a fuel collecting portion, an air flow-through portion, and a covering body to guide air to the fuel jetting opening, ensuring appropriate mixing of air and reformed gas and efficient heating of the reformer using combustor heat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the fuel utilization ratio of the fuel cell is increased to improve electric power generation efficiency, then the electric power generation efficiency is improved, but the amount of combustible gas available for the combustor decreases leading to deterioration of combustibility

Engineering Contradiction:
Improveelectric power generation efficiencyVSAvoidcombustibility
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A porous plug is introduced as an intermediary component between the fuel cell and combustor. This porous plug mediates the interaction between unconsumed reformed gas and combustion exhaust gas, enabling effective mixing that restores combustibility even when combustible gas concentration is low due to high fuel utilization ratio in the fuel cell.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical and chemical parameters of the gas mixture by introducing a porous plug that facilitates mixing. This alters the concentration distribution of combustible and oxidizing gases, transforming the gas composition to achieve stable combustion conditions despite high fuel cell fuel utilization.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the fuel utilization ratio of the fuel cell is increased, then electric power generation efficiency is improved, but the amount of heat generated by the combustor decreases making it difficult to maintain appropriate temperatures for the reformer and fuel cell

Engineering Contradiction:
Improveelectric power generation efficiencyVSAvoidtemperature of reformer and fuel cell
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The porous plug acts as a mediator that mixes combustion exhaust gas (containing heat) with unconsumed reformed gas before entering the combustor. This pre-mixing ensures that heat from the exhaust gas is effectively transferred to the incoming fuel gas, maintaining combustion temperature and enabling the combustor to provide adequate heat for the reformer and fuel cell even when combustible gas amount is reduced.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If heat insulation performance is improved or heat recovery performance is enhanced to compensate for decreased combustor heat, then temperature maintenance is improved, but manufacturing cost increases and system configuration becomes complex

Engineering Contradiction:
Improvetemperature of reformer and fuel cellVSAvoidsystem configuration
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The porous plug enables the system to be self-sufficient by utilizing the heat already present in the combustion exhaust gas. Instead of requiring external heat insulation improvements or additional heat recovery equipment, the system self-regulates temperature by internally mixing hot exhaust gas with incoming fuel gas, eliminating the need for complex external heat management systems.

Inventive Principle:
Principle #25Self-service

4Productivity

If the fuel utilization ratio is increased, then electric power generation efficiency is improved, but uncombusted components remain in combustion exhaust gas increasing burden on exhaust gas treatment catalyst

Engineering Contradiction:
Improveelectric power generation efficiencyVSAvoiduncombusted components in exhaust gas
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The porous plug serves as a mixing zone that ensures thorough combustion of unconsumed reformed gas by facilitating contact between fuel gas and oxidizing components in the exhaust gas. This intermediate mixing stage promotes complete combustion, minimizing uncombusted components in the final exhaust gas and reducing the burden on downstream exhaust gas treatment catalysts.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration improves the fuel utilization ratio, stabilizes combustion, reduces uncombusted components, and maintains a compact, cost-effective system design by enhancing mixing and heat transfer within the combustor.

Implementation Method 1

a reformer (4), which reforms raw fuel to generate reformed gas

Methodology Applied
Scientific EffectReforming reaction: Chemical Transport Reactions

Implementation Method 2

a solid-oxide fuel cell (2), which generates electric power by a reaction between the reformed gas and air

Methodology Applied
Scientific EffectFuel cell reaction: Fuel Cell

Implementation Method 3

a combustor (34), which mixes the reformed gas discharged from a fuel jetting opening (13) of the fuel collecting portion (9) with air flowing through the air flow-through portion (3), to combust the reformed gas

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 4

a covering body (8)... supplies the air toward the fuel jetting opening (13) of the fuel collecting portion (9)

Methodology Applied
Scientific EffectFluid flow guidance: Convection

Implementation Method 5

the reformer (4) reforms the raw fuel using combustion heat of the combustor (34)

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3297079B1Fuel cell system
Publication Date: 2020.01.15 PANASONIC HOLDINGS CORP
  • EP3297079B1 patent drawingFigure 1
  • EP3297079B1 patent drawingFigure 2
  • EP3297079B1 patent drawingFigure 3

AI summary

A fuel cell system includes: a reformer configured to reform raw fuel to generate reformed gas; a solid-oxide fuel cell configured to generate electric power by a reaction between the reformed gas and air; a fuel collecting portion provided adjacent to the solid-oxide fuel cell, the reformed gas remaining after the reaction of the solid-oxide fuel cell being collected at the fuel collecting portion; an air flow-through portion formed along an outer periphery of the fuel collecting portion; a combustor configured to mix the reformed gas discharged from a fuel jetting opening of the fuel collecting portion with the air flowing through the air flow-through portion, to combust the reformed gas and configured to mix the reformed gas discharged from a fuel jetting opening of the fuel collecting portion with the air flowing through the air flow-through portion, to combust the reformed gas; and a covering body provided so as to block flow of the air in a direction from the air flow-through portion toward the combustor along the reformer, wherein: the reformer reforms the raw fuel using combustion heat of the combustor; and the covering body supplies the air toward the fuel jetting opening of the fuel collecting portion.