Gas Turbine Compressor Inlet Segmentation for Exhaust Recirculation
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Solution Overview
Problem
Existing gas turbine systems face limitations in efficiently utilizing exhaust gas recirculation due to oxygen content issues, leading to increased plant size, costs, and reduced power output, as they require intermixing of fresh air and recirculated exhaust gases to ensure homogeneous combustion, which results in pressure losses and inefficiencies.
Innovation Solution
A method and gas turbine design where oxygen-reduced gas and fresh air are delivered separately to the compressor, with the oxygen-reduced gas primarily reaching the combustion chamber, allowing for a lower oxygen fraction and reduced mass flow, thereby minimizing plant size and costs, and optimizing combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If exhaust gas recirculation is implemented to reduce oxygen content and NOx emissions, then emissions are reduced, but the oxygen content becomes too low for complete combustion
Solution Approach 1:
The inlet flow is divided into two separate channels: one for fresh air and one for recirculated exhaust gas. This segmentation allows independent control of oxygen supply and exhaust gas recirculation, enabling high recirculation rates without compromising combustion reliability.
Solution Approach 2:
Different regions of the combustion chamber receive different gas compositions. The fresh air channel supplies oxygen-rich gas to specific zones where complete combustion is critical, while the exhaust gas channel delivers oxygen-reduced gas to other zones, creating local optimization of combustion conditions.
2Stability of the object's composition
If fresh air is intermixed with recirculated exhaust gases to ensure homogeneous combustion, then combustion stability is improved, but pressure losses increase and power output decreases
Solution Approach 1:
The inlet system is segmented into separate fresh air and exhaust gas channels that maintain distinct flows until the combustion chamber. This avoids premature mixing in the inlet ducts, reducing pressure losses while still achieving homogeneous combustion within the combustion chamber where mixing occurs under controlled conditions.
Solution Approach 2:
The mixing function is extracted from the inlet ducts and relocated to the combustion chamber. This allows the inlet system to focus on delivering gases with minimal pressure loss, while the combustion chamber provides the controlled environment necessary for homogeneous mixing and complete combustion.
3Productivity
If high recirculation rate is achieved to increase CO2 partial pressure and reduce emissions, then carbon dioxide separation efficiency is improved, but plant size and costs increase due to additional equipment
Solution Approach 1:
The separate inlet channels serve multiple functions: they enable high recirculation rates for CO2 enrichment, maintain sufficient oxygen supply for combustion, and reduce equipment complexity by eliminating the need for additional mixing devices. The combustion chamber itself performs the mixing function that would otherwise require separate equipment.
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 reduces plant size and operating costs while maintaining efficient combustion by minimizing the admixing of oxygen-reduced gas with cooling air, allowing for a lower mass flow with a reduced oxygen fraction, enhancing combustion efficiency and power output.
Implementation Method 1
a compressor (1) with an inlet cross section, a combustion chamber (4) following the compressor and in which the compressed gases are burnt
Implementation Method 2
a combustion chamber (4) following the compressor and in which the compressed gases are burnt by means of fuel (5)
Implementation Method 3
a turbine (7) following the combustion chamber in which the hot combustion gases are expanded
Data Source
AI summary
An exemplary gas turbine power plant includes a gas turbine with a compressor having a compressor inlet. A combustion chamber follows the compressor and a turbine follows the combustion chamber. A cross section of the compressor inlet includes an inner sector and an outer sector in relation to the axis of rotation of the compressor. A plurality of feed ducts introduces oxygen-reduced gas into the inner sector of the compressor inlet. The plurality of feed ducts is arranged in the compressor inlet so as to be distributed in a circumferential direction on a circle concentrically with respect to the axis of the gas turbine.