Hydrogen Fuel Cell Cold Start with Two-Mode Stack Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Natural gas power plants require a longer startup time to reach operational temperatures, which includes reformer heating, generating steam, and achieving high enough temperatures to operate with carbon monoxide in the fuel stream, limiting their efficiency and speed in generating power.
Innovation Solution
A hydrogen system incorporating a phosphoric acid fuel cell stack selectively coupled to a hydrogen fuel source, with a control system that operates the fuel cell stack in two modes: a first mode below a target temperature and a second mode at a higher temperature, allowing for efficient electricity generation and power augmentation using a cooling and heating assembly, and an energy storage system to provide power for heating augmentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If natural gas power plants use reformer heating and steam generation processes, then they can achieve stable operation with carbon monoxide in the fuel stream, but the startup time increases to several hours
Solution Approach 1:
The system performs preliminary heating of the fuel cell stack using an external heating source before initiating fuel processing. This preliminary action brings the stack to a temperature where fuel processing can begin, eliminating the need for lengthy reformer heating and steam generation required in conventional natural gas power plants.
Solution Approach 2:
The startup process is segmented into distinct phases: initial heating phase using external heating source, intermediate phase where fuel processing begins, and final phase where the system reaches full operating temperature. This segmentation allows the system to achieve stable operation more quickly by managing temperature progression in controlled stages.
2Productivity
If the fuel cell stack operates below target operating temperature, then it can generate electricity during cold start, but the power output is limited
Solution Approach 1:
The system maintains continuous electricity generation throughout the startup process. During the initial heating phase below target temperature, the fuel cell stack generates limited power, but as heating continues and temperature increases, power output continuously increases without interruption, achieving both early electricity generation and high final power output.
Solution Approach 2:
The system dynamically adjusts operating parameters as temperature changes. At lower temperatures, the system operates in a first mode with reduced power output, then transitions to a second mode at higher temperatures with increased power output. This dynamic adaptation allows electricity generation across the entire temperature range while maximizing power when conditions permit.
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 system enables the fuel cell stack to generate electricity efficiently at lower temperatures and increase power production significantly when reaching the target operating temperature, addressing the limitations of natural gas power plants by providing rapid startup and enhanced power output.
Implementation Method 1
a phosphoric acid fuel cell stack selectively coupled to a hydrogen fuel source
Implementation Method 2
an energy storage system configured to provide power to the heating source... causing the heating source to heat the fuel cell stack
Implementation Method 3
a cooling assembly for providing cooling and/or heating augmentation to the fuel cell stack
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A hydrogen system for generating power may include a fuel cell stack selectively coupled to a hydrogen fuel source. A control may be configured to cause the fuel cell stack to operate in a first mode in response to a first predetermined temperature threshold being met such that the fuel cell stack may generate electricity when below a target operating temperature. The control may be configured to cause the fuel cell stack to operate in a second mode in response to a second predetermined temperature threshold being met subsequent to the first predetermined temperature threshold being met. A method of operating a fuel cell stack is also disclosed.