Fuel Cell Startup Control via Dynamic Reforming Reaction Sequencing
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Solution Overview
Problem
Fuel cell apparatuses face challenges in efficiently starting up without deteriorating the reforming catalyst, as rapid increases in reforming target gas temperature can lead to carbon precipitation and catalyst degradation, especially after suspension periods.
Innovation Solution
A fuel cell apparatus with a controller that adjusts the reforming reaction sequence based on the temperatures of the reforming and vaporizing portions at startup, switching between partial oxidation reforming, autothermal reforming, and steam reforming to maintain efficient operation and prevent catalyst deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the reforming target gas temperature is rapidly increased during startup, then the startup speed is improved, but carbon precipitation occurs and the reforming catalyst deteriorates
Solution Approach 1:
The reforming reaction type is dynamically switched based on the reforming portion temperature. At low temperatures, partial oxidation reforming is performed; as temperature increases, it transitions to autothermal reforming, and finally to steam reforming at high temperatures. This dynamic adjustment of reaction type based on temperature conditions enables both rapid startup and prevention of carbon precipitation.
Solution Approach 2:
The invention changes the reaction type parameter (from partial oxidation to autothermal to steam reforming) as the temperature parameter increases. This parameter change strategy allows the system to adapt to different temperature conditions during startup, achieving fast warm-up while avoiding carbon precipitation that would occur with rapid temperature increase alone.
2Productivity
If partial oxidation reforming is performed at high temperature, then the reforming reaction efficiency is improved, but the reforming catalyst deteriorates rapidly
Solution Approach 1:
The invention selects different reaction types based on temperature parameters. Partial oxidation reforming is performed only at low temperatures where it is efficient and does not cause rapid catalyst deterioration. At high temperatures, steam reforming is performed instead, which maintains productivity while protecting the catalyst from rapid degradation.
Solution Approach 2:
The invention converts the potential harm of high-temperature partial oxidation reforming (which would rapidly deteriorate the catalyst) into a beneficial sequence by first using it for efficient low-temperature reforming, then transitioning to steam reforming at high temperatures. This sequential approach benefits from the efficiency of partial oxidation when appropriate while avoiding its harmful effects at high temperatures.
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 controlled reaction sequence reduces carbon precipitation and extends the lifespan of the reforming catalyst, ensuring efficient startup and operation of the fuel cell apparatus.
Implementation Method 1
the reforming reaction is performed by partial oxidation reforming
Implementation Method 2
the reforming reaction is switched from the partial oxidation reforming to autothermal reforming
Implementation Method 3
the reforming reaction is switched from the autothermal reforming to steam reforming
Implementation Method 4
a vaporizing portion generating steam to be supplied to the reforming portion
Implementation Method 5
the temperature of the reforming portion be increased by heat generated by burning unreacted gas (reforming target gas) and the fuel gas
Data Source
AI summary
Method of operating a fuel cell apparatus in which a reforming reaction in the reforming portion is selected by a controller at the starting time of the apparatus by comparing a first starting temperature of a reforming portion to a temperature T1 at which steam reforming can be performed and comparing a second starting temperature of a vaporizing portion to a temperature T2 at which a predetermined amount of steam can be generated by steam reforming. A reforming reaction starting with an autothermal reforming reaction is performed when the first starting temperature is not lower than T1 and the second starting temperature is lower than T2.