Steam Generator Reheat Tubes for Higher-Quality Turbine Steam
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Solution Overview
Problem
Traditional steam generators in power plants are inefficient as they typically accommodate a single type of secondary fluid input, limiting the use of primary heat for reheating lower pressure steam to high-quality or superheated steam, necessitating multiple expensive lower pressure turbines and leading to inefficiency and turbine blade damage.
Innovation Solution
A steam generator design with distinct helical heat exchange tubes for different secondary fluids, allowing simultaneous heating of condensed water and lower-pressure steam to produce high-quality steam for higher-pressure turbines, using materials resistant to nuclear reactor environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional steam generators accommodate a single type of secondary fluid input, then the design is simple, but energy extraction efficiency is limited and multiple expensive lower pressure turbines are required
Solution Approach 1:
The steam generator is designed with separate heat exchange tube bundles that can independently handle different secondary fluid inputs (condensed water and lower pressure steam). This multi-functionality allows the single steam generator to perform both steam generation and steam reheat operations, eliminating the need for separate turbines for different pressure levels and improving overall energy extraction efficiency.
Solution Approach 2:
The steam generator incorporates distinct tube bundles segmented by function: one bundle for heating condensed water to generate high-pressure steam, and another bundle for reheating lower pressure steam. This segmentation allows each bundle to be optimized for its specific function while maintaining a unified steam generator structure, resolving the contradiction between complexity and efficiency.
2Use of energy by moving object
If multiple lower pressure turbines are used to extract energy from lower pressure steam, then energy extraction is possible, but cost increases and turbine blade damage occurs
Solution Approach 1:
The steam generator acts as an intermediary by reheating lower pressure steam back to high-quality or superheated steam before it enters the turbine. This reheat process prevents moisture accumulation that causes blade damage and allows more efficient energy extraction, eliminating the need for multiple turbines and reducing overall system cost.
Solution Approach 2:
The system changes the thermal parameters of the steam by reheating it in the steam generator. Lower pressure steam is heated back to high temperature and quality, transforming it into a suitable state for efficient turbine operation. This parameter change enables single-turbine operation while maintaining high energy extraction efficiency and preventing blade damage.
3Reliability
If lower pressure steam is not reheated to high-quality steam, then the system is simpler, but turbine blade damage occurs and efficiency is reduced
Solution Approach 1:
The steam generator performs preliminary reheat action on lower pressure steam before it enters the turbine. By pre-heating the steam to high-quality or superheated state, the system prevents moisture formation during expansion that would cause blade damage. This preliminary action ensures reliable turbine operation while maintaining reasonable system complexity through integrated design.
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
Enhances energy extraction efficiency by producing higher-quality steam for more efficient turbines, reducing the need for lower-pressure turbines and minimizing blade damage, while maintaining cost-effectiveness and durability.
Implementation Method 1
a first set of heat exchange tubes for receiving lower pressure steam from a turbine outlet and heating the lower pressure steam to produce reheated steam
Implementation Method 2
Heat exchangers and power plants using the same to transfer energy from a primary heat source and heat exchange fluid
Implementation Method 3
The liquid water flows straight up through heat exchange tubes 32 and boils as it absorbs heat from liquid sodium passing downward inside body 11 around tubes 32
Implementation Method 4
The liquid water flows straight up through heat exchange tubes 32 and boils as it absorbs heat from liquid sodium
Implementation Method 5
converted to steam transferred from the heat of the primary loop in the steam generator
Data Source
Figure 1
Figure 2A~2B
Figure 3A
AI summary
Steam generators in power plants exchange energy from a primary medium to a secondary medium for energy extraction. Steam generators include one or more primary conduits and one or more secondary conduits. The conduits do not intermix the mediums and may thus discriminate among different fluid sources and destinations. One conduit may boil feedwater while another reheats steam for use in lower and higher-pressure turbines, respectively. Valves and other selectors divert steam and/or water into the steam generator or to other turbines or the environment for load balancing and other operational characteristics. Conduits circulate around an interior perimeter of the steam generator immersed in the primary medium and may have different cross-sections, radii, and internal structures depending on contained. A water conduit may have less flow area and a tighter coil radius. A steam conduit may include a swirler and rivulet stopper to intermix water in any steam flow.