Monolithic Catalyst in Gas Turbine Exhaust
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Solution Overview
Problem
There is a need for improved systems and methods to reduce NOx emissions from aircraft gas turbine engines, as existing technologies are inadequate in effectively mitigating these emissions.
Innovation Solution
The implementation of a gas turbine engine with a diffuser nozzle containing a monolithic catalyst structure, combined with a reducing agent injection system, specifically an ammonia-based reducing agent, to treat exhaust gases and reduce NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a catalyst system is used to reduce NOx emissions, then emission reduction is improved, but the complexity of the exhaust system increases
Solution Approach 1:
The patent combines the diffuser nozzle and catalyst support functions into a single integrated component. The diffuser nozzle serves dual purposes: conditioning the exhaust gas flow and providing structural support for the catalyst monolith, thereby reducing the number of separate components and simplifying the overall exhaust system architecture while maintaining effective NOx reduction
Solution Approach 2:
The diffuser nozzle is designed to perform multiple functions simultaneously: it acts as a flow conditioning element, a structural support for the catalyst, and an integral part of the exhaust treatment system. This multi-functionality reduces system complexity by eliminating the need for separate components for each function
2Speed
If exhaust gas flow velocity is high, then engine performance is improved, but catalyst interaction time is reduced
Solution Approach 1:
The diffuser nozzle performs preliminary action by conditioning the exhaust gas flow before it reaches the catalyst. It creates a controlled flow pattern and appropriate velocity distribution upstream of the catalyst, ensuring optimal interaction conditions are established in advance, which allows for effective catalysis even at high overall flow velocities
Solution Approach 2:
The diffuser nozzle creates local variations in flow velocity and pressure distribution within the exhaust stream. By controlling the local flow characteristics at different positions, it ensures that the exhaust gas spends adequate time in contact with the catalyst surface in critical zones, thereby maintaining effective interaction time despite high overall flow speeds
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 effectively reduces NOx emissions by increasing the interaction time of exhaust gases with the catalyst and utilizing the reducing agent to facilitate chemical reactions that convert NOx into nitrogen and water, achieving significant emission reduction.
Implementation Method 1
a monolithic catalyst structure configured to treat the exhaust gas stream
Implementation Method 2
utilizing the reducing agent to facilitate chemical reactions that convert NOx into nitrogen and water
Data Source
Figure 1
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Figure 4~5
AI summary
A gas turbine engine (20) for an aircraft includes a turbine section (28) and an exhaust section (30) configured to receive an exhaust gas stream from the turbine section (28). The exhaust section (30) includes a monolithic catalyst structure configured to remove nitrogen oxides (NOx) from the exhaust gas stream.