Gas Turbine Combustor Casing Cooling with Low-Temperature CO2
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Solution Overview
Problem
Conventional gas turbine facilities require expensive Ni-based alloys for the combustor casing due to exposure to high-temperature carbon dioxide, increasing manufacturing costs.
Innovation Solution
The gas turbine facility design incorporates a combustor casing that uses low-temperature carbon dioxide for cooling, allowing the combustor casing to be made of inexpensive Fe-based heat-resistant steel, such as CrMoV or CrMo steel, by isolating it from direct high-temperature carbon dioxide exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the combustor casing is made of Ni-based alloy to withstand high-temperature carbon dioxide, then the temperature resistance is improved, but the manufacturing cost increases
Solution Approach 1:
The combustor casing is divided into two distinct parts: an upstream side casing that contacts high-temperature carbon dioxide and requires Ni-based alloy for temperature resistance, and a downstream side casing that does not contact high-temperature carbon dioxide and can use inexpensive Fe-based heat-resistant steel. This segmentation allows each part to be made from appropriate materials based on its specific thermal exposure requirements, resolving the contradiction between temperature resistance and manufacturing cost.
Solution Approach 2:
Different material qualities are applied to different regions of the combustor casing based on local thermal conditions. The upstream side casing exposed to high-temperature carbon dioxide uses Ni-based alloy with superior temperature resistance, while the downstream side casing in cooler regions uses cost-effective Fe-based heat-resistant steel. This local quality approach ensures temperature resistance where needed while minimizing overall manufacturing cost.
2Ease of manufacture
If low-temperature carbon dioxide is used for cooling the combustor casing, then the manufacturing cost is reduced by using Fe-based steel, but the cooling effectiveness must be maintained
Solution Approach 1:
Low-temperature carbon dioxide is introduced as an intermediary cooling medium into the downstream side casing and through cooling channels. This cool carbon dioxide absorbs heat from the combustor casing components (combustor liner, transition piece, stator blades, rotor blades) and transfers it away, maintaining their temperature within acceptable ranges. The use of low-temperature carbon dioxide as a cooling intermediary enables the system to achieve effective cooling while allowing the casing to be constructed from cost-effective Fe-based heat-resistant steel rather than expensive Ni-based alloy throughout.
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 reduces manufacturing costs by utilizing less expensive materials while maintaining effective cooling of the combustor casing, preventing temperature increases and ensuring operational efficiency.
Implementation Method 1
The oxygen passing through the flow rate regulating valve 311 is heated by receiving heat from later-described combustion gas in a heat exchanger 312
Implementation Method 2
The carbon dioxide is heated in the heat exchanger 312 and is supplied into a combustor casing 350 accommodating the combustor 313
Implementation Method 3
The combustion gas passing through the heat exchanger 312 then passes through a cooler 316. At this time, the water vapor in the combustion gas condenses into water
Implementation Method 4
The carbon dioxide separated from the water vapor compressed in a compressor 317 interposed in the pipe 343 to become supercritical fluid
Data Source
AI summary
A gas turbine facility of an embodiment includes: a combustor casing; a combustor provided in the combustor casing; a cylinder surrounding a periphery of the combustor and dividing a space between the combustor casing and the combustor; a turbine rotated by combustion gas exhausted from the combustor; a heat exchanger cooling the combustion gas exhausted from the turbine; a pipe through which a part of the combustion gas cooled in the heat exchanger passes in the heat exchanger to be heated, the pipe guiding the combustion gas heated in the heat exchanger into the cylinder; and a pipe guiding another part of the combustion gas cooled in the heat exchanger to a space between the combustor casing and the cylinder.