Anode Recirculation Ejector with Heat Exchanger and Fuel Cooling
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Solution Overview
Problem
In solid oxide fuel cell systems, increasing the temperature of the primary flow medium to enhance the entrainment ratio in the anode recirculation system poses a risk to the stepping motor due to internal insulation requirements, as high-temperature gases can damage the motor.
Innovation Solution
Incorporating a heat exchanger to increase the temperature of the primary flow medium through heat exchange with the secondary flow medium, while using fuel at room temperature as a cooling medium for the valve core needle to prevent overheating and ensure safe operation of the adjustable ejector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the temperature of the primary flow medium is increased to enhance the entrainment ratio, then the performance of the ejector is improved, but the stepping motor will be damaged due to excessive temperature
Solution Approach 1:
The system divides the flow medium into two separate streams: a primary flow medium that is heated to high temperature to improve ejector performance, and a secondary cooling flow medium that passes through the valve core needle to maintain it within safe temperature limits. This segmentation allows both the high-temperature requirement for productivity and the temperature protection for reliability to be satisfied simultaneously.
Solution Approach 2:
The cooling flow medium acts as an intermediary substance that transfers heat away from the valve core needle. By introducing this intermediate cooling stream, the system can maintain the valve core needle at safe operating temperatures while still allowing the primary flow medium to reach the high temperatures needed for optimal ejector performance.
2Productivity
If high-temperature primary flow medium flows directly through the valve core needle to improve ejector performance, then the entrainment ratio increases, but the valve core needle temperature becomes too high causing motor damage
Solution Approach 1:
Different temperature conditions are applied to different parts of the system: the primary flow medium is heated to high temperature for optimal ejector performance, while the cooling flow medium is introduced specifically at the valve core needle location to maintain it within safe temperature limits. This local differentiation of thermal conditions resolves the contradiction between performance and component protection.
Solution Approach 2:
The cooling flow medium is introduced into the valve core needle before the high-temperature primary flow medium reaches it. This preliminary cooling action ensures that the valve core needle is already protected from excessive temperature rise, allowing the system to achieve high entrainment ratios without damaging the motor.
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 significantly increases the entrainment ratio and improves the performance of the anode recirculation system while ensuring the safe operation of the adjustable ejector, allowing for effective heat and water vapor utilization in the SOFC system.
Implementation Method 1
a heat exchanger to increase the temperature of the primary flow medium through heat exchange with the secondary flow medium
Implementation Method 2
using fuel at room temperature as a cooling medium for the valve core needle to prevent overheating
Data Source
AI summary
The present disclosure relates to the technical field of fuel cells, in particular to an anode recirculation system with an ejector for a solid oxide fuel cell. The heat exchanger is adopted in the anode recirculation system for the solid oxide fuel cell, the temperature of the fuel gas can be increased through heat exchange between the fuel gas as the primary flow medium and the cell exhaust as the secondary flow medium. The fuel at room temperature stored in the fuel tank is used as the cooling medium of the valve core needle to cool the valve core needle, so that it is ensured that a temperature of the stepping motor does not exceed a failure temperature.