Fuel Cell Device Partial Load Control
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Solution Overview
Problem
Fuel cell devices experience a decline in fuel utilization rate and current generation during partial load operations, leading to inefficient power generation and potential accidental combustion of excess fuel gas, which affects their load-following characteristics and operational reliability.
Innovation Solution
A fuel cell device with a cell stack, fuel gas supply unit, power conditioning unit, and controller that maintains a non-linear relationship between fuel utilization rate and electrical current generation by ensuring a minimum flow of fuel gas is supplied during partial load operations, thereby controlling the fuel utilization rate and current output effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the amount of fuel gas supplied to the cell stack is decreased during partial load operation, then the power generation output is reduced to match external load demand, but the fuel utilization rate declines and excess fuel gas accumulates leading to accidental combustion risk
Solution Approach 1:
The patent applies dynamics by making the fuel gas supply amount variable rather than fixed. The supply amount is dynamically adjusted based on the external load demand through a controller that receives load signals and regulates the fuel gas supply valve, allowing the system to adapt to changing power requirements while maintaining safe operation parameters.
Solution Approach 2:
The patent implements feedback control where the controller monitors the external load demand and adjusts the fuel gas supply amount accordingly. This closed-loop control system ensures that the fuel utilization rate remains within safe limits by continuously comparing the actual load with the supply rate and making real-time adjustments to prevent excess fuel accumulation.
2Productivity
If the fuel gas supply amount is reduced during partial load operation, then the power generation matches the external load, but the relationship between fuel utilization rate and current generation becomes unstable
Solution Approach 1:
The patent applies parameter changes by establishing a non-linear relationship between the fuel gas supply amount and the external load demand. Instead of a direct proportional relationship, the controller uses a non-linear control algorithm that adjusts the supply rate based on the square root or other non-linear functions of the load, thereby stabilizing the fuel utilization rate-current generation relationship across varying load conditions.
3Reliability
If excess fuel gas is supplied during partial load operation, then the fuel utilization rate is maintained, but the risk of accidental combustion increases due to unreacted fuel gas accumulation
Solution Approach 1:
The patent applies partial action by supplying only the necessary amount of fuel gas required for the external load demand rather than excessive fuel. The controller calculates the optimal supply amount that is sufficient for power generation but does not exceed the reaction capacity of the fuel cell, thereby preventing unreacted fuel gas accumulation while maintaining efficient fuel utilization.
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 enhances the efficiency and reliability of partial load operations by maintaining a stable fuel utilization rate and current generation, reducing the risk of accidental combustion and improving the load-following characteristic of the fuel cell device.
Implementation Method 1
a cell stack (1), a fuel gas supply unit (21), a power conditioning unit (31) and a controller (10)... The cell stack (1) includes a plurality of fuel cells electrically coupled to generate power with a fuel gas and an oxygen-containing gas
Data Source
AI summary
A fuel cell device is improved for operating conditions during a partial load operation. The fuel cell device comprises a cell stack formed by electrically connecting fuel cells for generating power by fuel gas and oxygen-containing gas; a fuel gas supply unit for supplying the fuel gas to the fuel cells; and a power adjustment unit for adjusting the amount of current that is supplied to an external load and a controller for controlling the fuel gas supply unit and the power adjustment unit. The controller adjusts, during the partial load operation of the fuel cell device and when the fuel gas supplied to the cell stack is at a low flow rate. The relationship between a fuel utilization rate of the cell stack and the amount of power generated by the cell stack can be nonlinear.