Sequential Gas Turbine Combustion With Steam Injection for NOx Control
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Solution Overview
Problem
Turbine engines face challenges with high operational pressures and temperatures leading to increased pollutant emissions, particularly NOx, and contrail formation due to water vapor condensation, which can degrade engine components and reduce durability.
Innovation Solution
Incorporation of a secondary combustor system that utilizes steam injection in combination with fuel to reduce maximum operating temperatures through a reheat cycle, separating combustion into multiple stages with intermediate temperature reductions, and a control system to manage fuel and steam distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high operational pressures and temperatures are used to increase power output, then power is improved, but NOx emissions increase and engine durability decreases
Solution Approach 1:
The combustion process is divided into multiple stages by introducing a secondary combustor between the turbine stages. The primary combustor handles initial combustion at high temperature, while the secondary combustor handles residual combustion at lower temperature, thereby reducing NOx emissions while maintaining power output.
Solution Approach 2:
Steam is introduced as an intermediary substance in the secondary combustor to cool the combustion gases and reduce temperatures before they enter the next turbine stage. This intermediary cooling mechanism enables power maintenance while reducing harmful NOx emissions.
2Power
If high operational pressures and temperatures are used to increase power output, then power is improved, but engine durability decreases
Solution Approach 1:
By segmenting the combustion process into primary and secondary combustors with intermediate cooling, the peak temperatures exposed to engine components are reduced. This segmentation allows maintenance of high power output while protecting components from excessive thermal stress, thereby improving durability.
Solution Approach 2:
Steam serves as an intermediary cooling medium that reduces the temperature of combustion gases between turbine stages. This intermediary action protects downstream components from high-temperature damage while preserving the power output generated in the primary combustor.
3Temperature
If water vapor is present in exhaust to cool combustion, then temperature is reduced, but contrail formation increases
Solution Approach 1:
Water vapor is extracted and utilized in the secondary combustor for cooling purposes, removing it from the exhaust stream before it can form contrails. This extraction and reuse of water vapor maintains temperature control while preventing harmful contrail formation in the atmosphere.
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
Reduces NOx emissions and enhances engine durability by lowering operating temperatures, increasing mass flow rate, and improving combustion stability, while allowing for smaller or more powerful engine designs.
Implementation Method 1
a steam system to increase total mass flow in the turbine section
Implementation Method 2
utilizes steam injection in combination with fuel to reduce maximum operating temperatures through a reheat cycle, separating combustion into multiple stages with intermediate temperature reductions
Data Source
AI summary
A turbine engine includes a compressor section for providing a compressed air flow, a fuel system for providing a primary combustor fuel supply, and a secondary combustor fuel supply. A primary combustor, located downstream of the compressor section, combusts the compressed air flow and the primary combustor fuel supply to generate primary combustion products. A turbine section, located downstream of the primary combustor, includes a turbine and a secondary combustor that further combusts the primary combustion products and the fuel from the secondary combustor fuel supply. A steam system provides a steam supply to the secondary combustor. The secondary combustor further combusts the primary combustion products and the secondary combustor fuel supply to generate secondary combustion products, and the turbine section is rotated by the secondary combustor steam supply and the inter-turbine combustion products.