Ammonia Fuel Supply System for Gas Turbine Combustion Stability
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Solution Overview
Problem
When ammonia is used as fuel for a gas turbine, it generates NOx, and there is a need to stabilize the combustion process and reduce NOx production, while ensuring stable operation from startup to rated load without external thermal energy.
Innovation Solution
A fuel supply system that includes a main ammonia line, a vaporizer, and a switching device to alternate between gaseous and liquid ammonia supply to the combustor, allowing liquid ammonia for startup and gaseous ammonia for high-load conditions to stabilize combustion and minimize NOx generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid ammonia is supplied to the combustor at startup, then stable combustion can be achieved without external thermal energy supply, but NOx generation increases
Solution Approach 1:
The patent changes the physical state parameter of ammonia from liquid to gaseous form. By vaporizing liquid ammonia to produce gaseous ammonia, the system achieves stable combustion without external thermal energy while reducing NOx generation, as gaseous ammonia burns more completely and cleanly
Solution Approach 2:
The patent utilizes the phase transition of ammonia from liquid to gas through vaporization. This phase change enables the ammonia to be supplied in a gaseous state that is more suitable for combustion, achieving both stable operation and reduced NOx emissions without requiring additional heating equipment
2Object-generated harmful factors
If gaseous ammonia is supplied to the combustor, then NOx generation is reduced, but external thermal energy supply is required for vaporization
Solution Approach 1:
The patent implements self-service by using the system's own operational characteristics to provide the thermal energy needed for vaporization. The compressor discharge air or exhaust gas, which is naturally hot during gas turbine operation, is used to vaporize the liquid ammonia, eliminating the need for external thermal energy supply
Solution Approach 2:
The patent recovers thermal energy that would otherwise be wasted. By using the hot compressor discharge air or exhaust gas to vaporize ammonia, the system recovers thermal energy from the gas turbine's operational byproducts, converting what would be discarded heat into useful vaporization energy
3Reliability
If ammonia flow rate is increased to ensure stable combustion, then combustion stability improves, but NOx generation increases
Solution Approach 1:
The patent changes the physical state parameter of ammonia from liquid to gaseous form. Gaseous ammonia at lower flow rates provides stable combustion with reduced NOx generation compared to liquid ammonia, as the gaseous state ensures more complete and controlled combustion
Solution Approach 2:
The patent substitutes the mechanical/physical approach of increasing liquid ammonia flow rate with a chemical/physical state change approach. Instead of adding more liquid ammonia to improve combustion stability, the system vaporizes ammonia to change its state, achieving stable combustion at lower flow rates with reduced NOx emissions
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 stable ammonia combustion and reduces NOx generation throughout the gas turbine's operation from startup to rated load, using only ammonia as fuel.
Implementation Method 1
a vaporizer configured to heat and vaporize the liquid ammonia via heat exchange between a heating medium and the liquid ammonia pressurized by the main ammonia pump
Implementation Method 2
a vaporizer configured to heat and vaporize the liquid ammonia via heat exchange between a heating medium and the liquid ammonia pressurized by the main ammonia pump
Data Source
AI summary
Provided is a fuel supply system including a main ammonia line through which liquid ammonia flows; a vaporizer connected to an end of the main ammonia line and configured to heat and vaporize the liquid ammonia via heat exchange between a heating medium and the liquid ammonia; a gaseous ammonia line connected to the vaporizer, the gaseous ammonia line configured to guide a gaseous ammonia, which is ammonia vaporized by the vaporizer, as fuel to a combustor of a gas turbine; a liquid ammonia line configured to guide liquid ammonia which has not undergone heat exchange with the heating medium at the vaporizer as fuel to the combustor; and a switching device configured to switch an ammonia supply state between a first state in which the gaseous ammonia is guided from the gaseous ammonia line to the combustor and a second state in which the liquid ammonia is guided from the liquid ammonia line to the combustor.