Fuel Cell Start-Up Heating via Electrolysis Hydrogen Generation
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Solution Overview
Problem
High temperature fuel cell systems face challenges in achieving efficient start-up heating due to high earth fault currents generated by electrical heaters and excessive internal reforming, which increases the need for external heating sources, leading to larger and more costly systems.
Innovation Solution
Integrating an electrolysis mode of operation for part of the fuel cells to produce hydrogen, which is then circulated and used to heat other fuel cells, reducing the need for external heating and internal reforming, thereby minimizing fuel feed and heat requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If electrical heaters are used for heating fuel cells during start-up, then heating capability is improved, but earth fault currents increase and system complexity increases
Solution Approach 1:
The fuel cell system uses itself to heat during start-up by operating some cells in electrolysis mode to produce hydrogen that is then used by other cells in fuel cell mode to generate heat, eliminating the need for separate electrical heaters and reducing system complexity
Solution Approach 2:
The fuel cell stack is divided into different functional groups: some cells operate in electrolysis mode while others operate in fuel cell mode, allowing the system to internally generate both hydrogen and heat during start-up without requiring external heating devices
2Quantity of substance
If internal reforming is increased to produce hydrogen for fuel cells, then hydrogen availability is improved, but heat loss increases and external heating requirements increase
Solution Approach 1:
Instead of using internal reforming to produce hydrogen (which consumes heat), the system reverses the process by using electrolysis to produce hydrogen, eliminating the endothermic reforming reaction and its associated heat loss while still providing hydrogen to the fuel cells
3Temperature
If external heating sources are increased to compensate for internal reforming heat loss, then temperature maintenance is improved, but system cost and size increase
Solution Approach 1:
The system generates its own heat internally by operating some cells in fuel cell mode to produce electrical energy and heat, which is then used to heat the entire stack during start-up, eliminating the need for large external heating sources and reducing system size and cost
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 approach allows for smaller, cheaper heating sources and a more compact fuel cell system by reducing the need for external heating and internal reforming, achieving heat balance at lower currents and cost savings.
Implementation Method 1
provides a part of the fuel cells with voltage and current to facilitate an electrolysis mode of operation producing hydrogen
Implementation Method 2
The reactants fed to the fuel cell devices undergo a process in which electrical energy and heat are produced as a result of an exothermal reaction
Implementation Method 3
internal reforming, fuel cell reactions... These mechanisms for heat removal include endothermic reactions taking place at fuel cell anodes (internal reforming)
Data Source
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AI summary
The object of the invention is an arrangement for enhancing heating properties of a high temperature fuel cell device, each fuel cell (103) in the fuel cell device comprising an anode side (100), a cathode side (102), an electrolyte (104) between the anode side and the cathode side, and the arrangement comprises at least one heating source for heating the fuel cells (103) and means for determining essential temperature information of the fuel cells (103). The arrangement comprises means (122) to provide a part of the fuel cells (103) with voltage and current to facilitate an electrolysis mode of operation producing hydrogen, means (123) to simultaneously load another part of the fuel cells and means (109) for circulating fuel through the anode sides (100) of the fuel cells (103) to supply at least part of the hydrogen produced by the electrolysis to the fuel cells (103) being loaded.