Fuel Cell-Combustor Assembly With Pre-Burner Air Heating
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Solution Overview
Problem
Existing fuel cell-combustor combinations in gas turbine engines require conduits for air flow management, increasing system size and weight, and necessitate heating elements to heat air for fuel cell operation, which complicates the system.
Innovation Solution
Integration of a pre-burner system within the combustor to control air temperature and a catalytic partial oxidation convertor to develop a hydrogen-rich fuel stream, eliminating the need for additional conduits and heating elements by directly channeling air and fuel exhaust into the combustor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conduits are used to direct air flow into and out of fuel cells, then air flow management is achieved, but system size increases
Solution Approach 1:
The fuel cell stack is integrated directly into the combustor structure, merging two separate components (fuel cell and combustor) into a unified assembly. This eliminates the need for separate conduits to direct air flow between them, as the air naturally flows from the compressor through the fuel cell stack and then into the combustor chamber, thereby reducing system size while maintaining effective air flow management.
2Temperature
If heating elements are added to heat air for fuel cell operation, then air temperature requirement is met, but system weight increases
Solution Approach 1:
The air is pre-heated by passing it through the hot exhaust gases of the combustor in a heat exchanger arrangement before entering the fuel cell stack. This preliminary heating action utilizes waste heat from the combustor, eliminating the need for additional heating elements and reducing system weight while ensuring the air temperature meets fuel cell operational requirements.
Solution Approach 2:
The hot exhaust gases from the combustor, which would normally be wasted heat, are utilized to pre-heat the air entering the fuel cell stack. This converts a harmful waste product (excess heat) into a beneficial resource (heated air), eliminating the need for additional heating elements and reducing system weight.
3Temperature
If heating elements are added to heat air for fuel cell operation, then air temperature requirement is met, but device complexity increases
Solution Approach 1:
The combustor serves multiple functions: it acts as both the combustion chamber for burning fuel and as a heat exchanger to pre-heat air for the fuel cell stack. This multi-functionality eliminates the need for separate heating elements and reduces device complexity by having one component perform multiple roles.
Solution Approach 2:
The system uses its own exhaust heat to pre-heat the air for the fuel cell stack, making the system self-sufficient. The combustor's waste heat automatically serves the heating requirement of the fuel cell, eliminating the need for external heating elements and reducing system complexity.
4Volume of moving object
If fuel cell stack is integrated with combustor, then system size is reduced, but thermal management becomes more challenging
Solution Approach 1:
A heat exchanger is introduced as an intermediary component between the combustor exhaust and the fuel cell air inlet. This intermediary efficiently transfers heat from the hot exhaust gases to the cooler air stream, managing the thermal interaction between the two components while maintaining their functional integration and reducing overall system size.
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 configuration enhances fuel efficiency by reducing the need for additional ducting and heating elements, allowing for efficient operation of fuel cells within the combustor, potentially reducing fuel burn by 10% or more and improving thermal management.
Implementation Method 1
a pre-burner system fluidly connected to the fuel cell stack, the pre-burner system being configured to control a temperature of an air flow directed into the fuel cell stack
Implementation Method 2
Compressed air that is output by the compressors flows along the length of the engine and into the fuel cells. Part of this air is consumed by the fuel cells in generating electrical energy.
Implementation Method 3
The rest of the air can flow through or around the fuel cells and into a combustor. This air is then mixed with fuel and combusted in a combustor of the engine.
Implementation Method 4
a catalytic partial oxidation (C-POX) convertor for developing a hydrogen rich fuel stream
Data Source
AI summary
An engine assembly includes a combustor, a fuel cell stack integrated with the combustor, and a pre-burner system fluidly connected to the fuel cell stack. The fuel cell stack is configured to direct fuel and air exhaust from the fuel cell stack into the combustor. The pre-burner system is configured to control a temperature of an air flow directed into the fuel cell stack. The combustor is configured to combust the fuel and air exhaust from the fuel cell stack into one or more gaseous combustion products that drive a downstream turbine. The engine assembly can further include a catalytic partial oxidation convertor that is fluidly connected to the fuel cell stack. The catalytic partial oxidation convertor is configured to develop a hydrogen rich fuel stream to be directed into the fuel cell stack.