HRSG Integrated Heat Exchangers for Compressed Air Cooling
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Solution Overview
Problem
Traditional combined power generation systems require a separate external heat exchanger for cooling compressed air, leading to increased construction costs and inefficiencies, particularly during startup when water cannot be used as a cooling source.
Innovation Solution
Integrating multiple heat exchangers within the heat recovery steam generator (HRSG) to utilize exhaust gases for cooling compressed air, eliminating the need for a separate cooling system and reducing startup time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a separate external heat exchanger is used to cool compressed air, then the turbine section can be cooled, but additional construction sites and piping are required, increasing system complexity and cost
Solution Approach 1:
The patent combines the cooling function with the existing HRSG by integrating heat exchangers into its structure. The HRSG serves dual purposes: generating steam for power generation and cooling compressed air for the turbine section, thereby eliminating the need for a separate external cooling system and reducing overall system complexity
Solution Approach 2:
The HRSG is designed to perform multiple functions simultaneously: it generates steam for the steam turbine while also serving as a cooling system for the compressed air. This multi-functionality eliminates the need for dedicated separate equipment and reduces the number of construction sites required
2Temperature
If a separate external heat exchanger is used for cooling, then compressed air can be cooled, but startup time is increased due to inability to use water as cooling source during startup
Solution Approach 1:
The system uses its own exhaust gases to cool the compressed air during startup, eliminating the need for external water cooling sources. The exhaust gases from the gas turbine provide the necessary cooling capacity during all operational phases including startup, thereby reducing startup time
Solution Approach 2:
The heat exchangers integrated into the HRSG act as intermediaries that transfer heat from the compressed air to the exhaust gases. This intermediary mechanism enables efficient heat transfer during startup when water cooling is not available, allowing the system to cool compressed air using only its own exhaust heat
3Loss of time
If multiple heat exchangers are integrated within the HRSG, then startup time is reduced and construction sites are minimized, but the HRSG structure becomes more complex
Solution Approach 1:
The heat exchangers are nested within the existing HRSG structure, utilizing the available space inside the HRSG housing. This nesting approach allows multiple heat exchangers to be integrated without requiring additional external construction sites, while the modular nested design minimizes structural disruption
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 solution effectively cools compressed air using exhaust gases, optimizing turbine section temperatures and eliminating the need for additional construction sites, thereby enhancing system efficiency and reducing costs.
Implementation Method 1
a plurality of heat exchangers provided inside a heat recovery steam generator (HRSG) to cool the compressed air by performing heat exchange between the compressed air and exhaust gases
Implementation Method 2
a heat recovery steam generator (HRSG) in which steam is generated by heat of the exhaust gases from the gas turbine
Data Source
AI summary
A combined power generation system includes a gas turbine including a compressor configured to compress air, a combustor configured to mix the compressed air from the compressor and fuel and combust a mixture of the compressed air and fuel, and a turbine section in which rotational power is obtained by combustion gases generated by the combustor. The system also includes a heat recovery steam generator (HRSG) in which steam is generated by heat of exhaust gases from the gas turbine, and a steam turbine driven by the steam generated by the HRSG, wherein the HRSG includes a plurality of heat exchangers provided to cool the compressed air by heat exchange between the compressed air and the exhaust gases.