Fuel Cell Start-Up Channel Clogging Prevention
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Solution Overview
Problem
In conventional fuel cell systems, hydrogen-containing gas supplied during start-up can diffuse into lower-temperature channels, leading to condensed water generation and potential channel clogging, which inhibits hydrogen supply to the fuel cell during power generation.
Innovation Solution
A fuel cell system design that includes a hydrogen generator, combustor, fuel cell, and channels with on-off valves and an oxidation gas supply unit, where oxygen is supplied through a third channel to the first channel downstream of a branch portion during start-up to prevent condensed water accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen-containing gas is supplied through the first channel during start-up, then the fuel cell can be operated, but condensed water may generate and clog the channel
Solution Approach 1:
The system performs preliminary warming-up of the first channel by supplying hydrogen-containing gas through the second channel (bypass) before opening the first on-off valve to supply gas through the first channel. This preliminary action prevents condensed water generation by ensuring the channel temperature is sufficiently high before main operation begins.
Solution Approach 2:
The second channel acts as an intermediary pathway during the transition period. It allows hydrogen-containing gas to flow and warm up the system components (particularly the first channel) without directly exposing the first channel to cold gas that would cause condensation. The second channel mediates between the hydrogen generator and the fuel cell during the warm-up phase.
2Ease of operation
If the first on-off valve is closed and second on-off valve is opened during start-up, then hydrogen-containing gas can be supplied to combustor, but hydrogen-containing gas may diffuse into the first channel and cause clogging
Solution Approach 1:
The system applies preliminary anti-action by maintaining the first on-off valve in a closed state during the initial start-up phase when the second on-off valve is opened. This prevents hydrogen-containing gas from diffusing into the first channel before the channel is warmed up, thereby preventing condensation and clogging before the harmful effect can occur.
Solution Approach 2:
The system performs the preliminary action of warming up the first channel through controlled gas flow via the second channel before allowing direct supply through the first channel. This sequence ensures the channel is prepared (warmed up) before the main hydrogen supply path is activated, preventing the harmful condensation effect.
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 design reduces the likelihood of channel clogging caused by condensed water, ensuring uninterrupted hydrogen supply to the fuel cell during start-up and power generation.
Implementation Method 1
a reformer configured to generate a hydrogen-containing gas by a reforming reaction using a raw material and steam
Implementation Method 2
a combustor configured to supply heat for the reforming reaction to the reformer
Implementation Method 3
a fuel cell configured to generate electric power by using the hydrogen-containing gas supplied from the hydrogen generator
Implementation Method 4
the hydrogen-containing gas gradually diffuses to a first channel located downstream of a branch portion
Data Source
AI summary
A fuel cell system (100) includes: a hydrogen generator (2) including a reformer (3); a combustor (5) configured to supply heat to the reformer (3); a fuel cell (1); a first channel (10); a second channel (8); a third channel (16) through which an oxidation gas flows, the oxidation gas being supplied to the first channel (10) extending between a branch portion (10a) and the fuel cell (1); a first on-off valve (7a) provided on the first channel (10) located downstream of a meeting portion (10c); a second on-off valve (6) provided on the second channel (8); an oxidation gas supply unit (15) provided on the third channel (16); and a controller (200) configured such that when the first on-off valve (7a) is closed and the second on-off valve (6) is opened, and a hydrogen-containing gas is discharged from the hydrogen generator (2) at the time of start-up, the controller (200) activates the oxidation gas supply unit (15) to supply the oxidation gas through the third channel (16) to the first channel (10) located downstream of the branch portion (10c).