Gas Turbine Plant Exhaust Gas Recirculation Temperature Control
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Solution Overview
Problem
Conventional gas turbine systems face inefficiencies due to wide temperature fluctuations, which affect compressor performance and require larger surge margins, leading to increased fuel consumption and manufacturing costs.
Innovation Solution
Regulating the temperature of the fresh gas/exhaust gas mixture at the compressor inlet using a recirculation cooler and valve controlled by a control device, allowing for precise adjustment of the recirculated exhaust gas temperature and volume flow to maintain a constant inlet temperature, thereby reducing temperature fluctuations and compressor surge margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional compressors are designed to operate within a wide ambient temperature range (-20°C to +50°C), then the compressor can handle various environmental conditions, but the surge line margin must be correspondingly large, reducing compressor efficiency
Solution Approach 1:
The invention changes the operating parameters of the compressor by actively controlling the inlet gas temperature to a predetermined value using exhaust gas recirculation with cooling. This allows the compressor to operate at optimal efficiency points regardless of ambient temperature variations, resolving the contradiction between adaptability and efficiency by decoupling the compressor's performance from environmental conditions through parameter control
Solution Approach 2:
The control device continuously monitors the actual temperature of the fresh gas-exhaust gas mixture and adjusts the recirculation rate and cooling capacity accordingly to maintain the predetermined target temperature. This feedback mechanism ensures the compressor operates at optimal efficiency across varying ambient conditions without requiring a large surge line margin
2Productivity
If the surge line margin is reduced to increase compressor efficiency, then more power is available to drive the generator and manufacturing costs decrease, but the compressor becomes more sensitive to temperature fluctuations and operating conditions
Solution Approach 1:
The control device uses feedback control to continuously adjust the recirculation rate and cooling capacity based on the actual temperature measurement, ensuring the inlet temperature remains at the predetermined optimal value. This maintains stable compressor operation with a reduced surge line margin, resolving the contradiction between efficiency and reliability
Solution Approach 2:
The invention makes the recirculation system dynamic by allowing real-time adjustment of the recirculation rate and cooling capacity in response to changing operating conditions. This dynamic control ensures the compressor maintains stable operation at optimal efficiency points even with a reduced surge line margin
3Object-generated harmful factors
If exhaust gas recirculation is used to reduce oxygen content and NOx formation, then emissions are reduced, but the temperature of the fresh gas-exhaust gas mixture becomes difficult to control
Solution Approach 1:
The recirculation cooler acts as an intermediary device between the exhaust gas path and the fresh gas path, providing controlled cooling of the recirculated exhaust gases. This allows the system to maintain the desired temperature of the fresh gas-exhaust gas mixture while still achieving NOx reduction through exhaust gas recirculation, resolving the contradiction between emissions control and temperature management
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 increases compressor efficiency by 1.5%, reduces fuel consumption, and allows for a smaller compressor design with fewer stages, enhancing overall gas turbine system efficiency.
Implementation Method 1
The recirculation cooler (18) is designed to cool the recirculated combustion exhaust gas from the gas turbine (4) to a temperature below the ambient temperature
Implementation Method 2
regulating the temperature of the fresh gas/exhaust gas mixture at the compressor inlet using a recirculation cooler and valve controlled by a control device, allowing for precise adjustment of the recirculated exhaust gas temperature and volume flow to maintain a constant inlet temperature
Data Source
Figure 1~2
AI summary
The present invention relates to a gas turbine plant (1), particularly in a power plant for electricity generation, comprising a turbine unit (2) with a turbine (4), a compressor (5), and a combustion chamber (6) arranged in a gas path (9) connecting the compressor (5) to the turbine (4), and an exhaust gas recirculation device (3) that directs combustion exhaust gas from the turbine (4) from an exhaust gas path (14) connected to the turbine (4) via a recirculation path (16) to a fresh gas path (13) connected to the compressor (5). To improve the efficiency of the gas turbine plant (1), a control device (17) regulates a volume flow rate and/or a temperature of the recirculated combustion exhaust gases such that a fresh gas-exhaust gas mixture entering the compressor (5) has a predetermined target temperature.