Ammonia Fuel Cracking for Turbine Engine Startup and Combustion
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Solution Overview
Problem
Existing fuel systems for powerplants, such as gas turbine engines, utilizing ammonia as a non-hydrocarbon fuel face inefficiencies and opportunities for improvement.
Innovation Solution
A fuel system for powerplants that includes a heat exchanger to vaporize liquid ammonia into ammonia gas, a cracker to partially crack ammonia into hydrogen and nitrogen gases, and a fuel injector to deliver these gases for combustion, utilizing heat energy from a heating device or the turbine engine during startup and post-startup operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ammonia is used as fuel in powerplants, then non-hydrocarbon fuel utilization is achieved, but fuel system complexity increases due to additional components like crackers and heat exchangers
Solution Approach 1:
The patent combines the vaporization and cracking functions into an integrated system where the heat exchanger and cracker work together in sequence. The heat exchanger vaporizes liquid ammonia and the cracker immediately processes the vapor, merging storage, vaporization, and chemical decomposition functions into a unified fuel preparation system that reduces overall complexity despite adding ammonia-specific components.
Solution Approach 2:
The fuel system is designed to handle multiple operating modes using the same core components. The heat exchanger serves both startup mode (vaporizing ammonia) and steady-state mode (processing cracked gases), while the cracker operates in both partial cracking mode during startup and full cracking mode during steady-state operation, making the system multi-functional and adaptable.
2Quantity of substance
If ammonia vaporization and cracking is implemented, then hydrogen gas production is achieved, but energy consumption increases during startup operation
Solution Approach 1:
The system performs preliminary vaporization of ammonia in the heat exchanger before cracking. By pre-heating and vaporizing the ammonia fuel before it enters the cracker, the system prepares the fuel in advance, allowing the cracking process to proceed more efficiently and reducing the total energy required during startup operation.
Solution Approach 2:
The system changes the physical state of ammonia from liquid to gas through controlled heating in the heat exchanger, and then changes the chemical composition through cracking. These parameter changes (temperature, phase, molecular structure) are implemented in sequence to optimize energy utilization, allowing hydrogen production while managing energy consumption through staged processing.
3Productivity
If heat exchanger and cracker are added to the fuel system, then ammonia conversion efficiency is improved, but device complexity increases
Solution Approach 1:
The ammonia conversion process is segmented into distinct functional stages: liquid ammonia storage, vaporization in the heat exchanger, and cracking in the cracker. This segmentation allows each component to be optimized for its specific function, improving overall conversion efficiency while keeping individual components relatively simple and manageable.
Solution Approach 2:
The heat exchanger acts as an intermediary between the liquid ammonia storage and the cracker. It transforms liquid ammonia into vapor form, serving as a mediating step that enables efficient cracking while protecting the cracker from liquid fuel issues. This intermediary component improves conversion efficiency by ensuring proper fuel preparation before cracking.
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
Enhances the efficiency and flexibility of ammonia utilization in powerplants by providing a reliable source of hydrogen and nitrogen gases for combustion, optimizing startup and steady-state operations.
Implementation Method 1
The heat exchanger is configured to vaporize a first flow of liquid ammonia received from the reservoir into ammonia gas using heat energy
Implementation Method 2
The cracker configured to at least partially crack the ammonia gas into hydrogen gas and nitrogen gas
Implementation Method 3
a flow of ammonia is heated using heat energy during initial startup operation and post-startup operation of a turbine engine
Implementation Method 4
The aircraft engine is configured to generate the heat energy during post-startup operation of the aircraft engine
Data Source
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AI summary
A fuel system (28) includes a reservoir (84), a heat exchanger (104), a heating device (90), a cracker (92) and a fuel injector (70). The heat exchanger (104) is configured to vaporize a first flow of liquid ammonia received from the reservoir into ammonia gas using heat energy. The heat exchanger (104) is configured to receive the heat energy from the heating device (90) during a first operating mode. The heat exchanger (104) is configured to receive the heat energy from a turbine engine (26) a second operating mode. The cracker (92) configured to at least partially crack the ammonia gas into hydrogen gas and nitrogen gas. The fuel system (28) is configured to deliver the hydrogen gas or a combination of the hydrogen gas and the nitrogen gas to a fuel injector (70) for injection into a combustion chamber (66).