Sequential Combustion Gas Turbine Emission Control
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Solution Overview
Problem
Existing gas turbine assemblies with sequential combustion face challenges in minimizing emission values and achieving compactness, particularly at higher outputs, due to high exhaust gas temperatures and uncontrolled combustion reactions.
Innovation Solution
A gas turbine assembly design featuring tubular combustion chamber elements arranged around the rotor with a transition duct that acts as a heat exchanger and mixer, allowing for sequential combustion and efficient fuel injection to prevent premature autoignition, while utilizing a common rotor for compactness and integrating with a steam turbine for enhanced efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If sequential combustion is implemented with two combustion chambers to improve emission values, then emission values are improved, but the axial length of combustion chambers increases
Solution Approach 1:
The combustion chamber is divided into two separate combustion chambers arranged in sequence along the axial direction. Each combustion chamber performs a combustion stage independently, allowing sequential combustion to reduce emissions while maintaining a compact overall structure through modular segmentation rather than a single long chamber.
Solution Approach 2:
The two combustion chambers are arranged axially rather than radially or in parallel, utilizing the axial dimension efficiently. This arrangement allows sequential combustion stages to be compactly integrated along the turbine axis without significantly increasing the radial footprint or overall machine length.
2Device complexity
If fuel is introduced directly into hot combustion exhaust gases without cooling, then the process is simplified, but uncontrolled combustion reactions occur leading to high emission values
Solution Approach 1:
The combustion exhaust gases from the first combustion chamber are cooled before fuel is introduced in the second combustion chamber. This preliminary cooling action prevents premature autoignition and ensures controlled combustion reactions, thereby reducing emission values while maintaining process simplicity.
Solution Approach 2:
The temperature parameter of the combustion exhaust gases is changed by cooling them before the second combustion stage. This parameter change from high temperature to a controlled lower temperature prevents uncontrolled combustion reactions and reduces harmful emissions while keeping the system relatively simple.
3Object-generated harmful factors
If cooling is applied to combustion exhaust gases to prevent premature ignition, then emission values are reduced, but the mass flow increases
Solution Approach 1:
Cooling media are introduced into the combustion exhaust gases to induce phase transitions and absorb heat. This cooling process reduces the temperature to prevent premature ignition and reduce emissions, while the increase in mass flow is managed through the sequential combustion chamber design and turbine integration.
Solution Approach 2:
Cooling media act as intermediaries between the hot combustion exhaust gases and the fuel to be introduced. These intermediaries absorb excess heat and control the temperature, preventing uncontrolled combustion while the resulting mass flow increase is utilized by the turbine for power generation.
4Object-generated harmful factors
If an interposed turbine is added between two combustion stages to control combustion, then emission values are improved, but the device complexity increases
Solution Approach 1:
The turbine serves multiple functions: it extracts work from the combustion gases, drives the compressor, and provides a means to control the combustion process between stages. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in device complexity while still achieving emission reduction through controlled sequential combustion.
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 design improves combustion efficiency and reduces emissions by ensuring controlled combustion, allowing for flexible operation and increased power output, while maintaining compactness and efficient heat recovery.
Implementation Method 1
the combustion gases of the first combustion chamber can be cooled by means of heat transmission
Implementation Method 2
the ignition of the fuel introduced is delayed until sufficient mixture formation can take place in order to form the desired lean fuel/oxidizer mixture between the combustion exhaust gases of the first combustion chamber and the fuel additionally supplied
Data Source
AI summary
The invention relates to a gas turbine assembly which substantially includes at least one compressor, at least one first burner, at least one second burner that is connected downstream of the first burner, and at least one turbine that is connected downstream of the second burner. At least the first and second burner form a component of a tubular or quasi-tubular combustion chamber element in the flow direction of the combustion path of the burners. The combustion chamber element being closed or quasi-closed and extending between the compressor and the turbine. The combustion chamber elements are arranged around the rotor of the gas turbine assembly in the shape of a ring.