Dynamic Gain Control for SOFC-MGT Exhaust Fuel Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In conventional combined power generation systems, the fluctuation in exhaust fuel gas flow rate from a solid oxide fuel cell (SOFC) to a micro gas turbine (MGT) combustor leads to significant differential pressure changes, causing instability and prolonged activation times, requiring additional pressure adjustment valves.
Innovation Solution
A control apparatus that adjusts the gain of the flow rate adjustment valve based on the cooperative operation state of the fuel cell and internal combustion engine, using feedback from flow rate and gas density to stabilize the system, eliminating the need for separate pressure adjustment valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a flow rate adjustment valve is used to control exhaust fuel gas flow rate, then the flow rate can be adjusted, but the differential pressure fluctuates significantly causing instability and prolonged activation time
Solution Approach 1:
The control apparatus uses feedback control to detect differential pressure between the fuel cell interior and exterior, and adjusts the flow rate adjustment valve opening based on this feedback to maintain stable differential pressure during activation and operation
Solution Approach 2:
The system dynamically adjusts the gain of the flow rate adjustment valve according to the operational state (activation state or rated operation state) to optimize control response characteristics at different operating conditions
2Speed
If the gain to the flow rate adjustment valve opening is increased to improve flow rate control sensitivity, then flow rate adjustment becomes more responsive, but differential pressure fluctuation increases causing load on the fuel cell
Solution Approach 1:
The gain of the flow rate adjustment valve is made dynamic rather than fixed, being adjusted based on the operational state of the fuel cell. During activation state, a lower gain is used to minimize pressure fluctuations, while during rated operation state, the gain can be increased for faster response without causing excessive pressure variations
3Stability of the object's composition
If additional pressure adjustment valves are added to control differential pressure, then pressure stability can be improved, but device complexity increases
Solution Approach 1:
The flow rate adjustment valve is made to serve multiple functions: it controls both the exhaust fuel gas flow rate and the differential pressure across the fuel cell. By adjusting the gain and using feedback control, the single valve performs what would traditionally require separate flow rate and pressure adjustment valves
Solution Approach 2:
The control functions for flow rate adjustment and pressure control are merged into a single control system that operates the flow rate adjustment valve. The feedback control loop combines both flow rate and differential pressure control objectives into one unified control mechanism
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 enables prompt and stable operation of the combined power generation system by sensitively managing flow rate changes, improving system operability and reducing the need for additional pressure adjustment mechanisms.
Implementation Method 1
Fuel cells are power generation apparatuses utilizing a power generation scheme by electrochemical reaction
Implementation Method 2
exhaust fuel gas discharged from the SOFC is burned by a combustor
Implementation Method 3
a turbine is driven by combustion gas, and power is generated
Data Source
AI summary
A combined power generation system is promptly activated, and stable operation thereof is provided. A control apparatus of the combined power generation system that generates power by performing cooperative operation combining an SOFC and an MGT, in which the combined power generation system includes: an exhaust fuel gas supply line that supplies exhaust fuel gas to a combustor of the MGT from the SOFC; a recirculation line that branches from the exhaust fuel gas supply line to flow the exhaust fuel gas to the SOFC; and a flow rate adjustment valve provided on a path of the exhaust fuel gas supply line, and in which a gain to an opening of the flow rate adjustment valve is adjusted according to an cooperative operation state of the SOFC and the MGT.