Steam Dilution for Reheater Temperature Control
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Solution Overview
Problem
Combined cycle power generation systems face challenges in controlling steam temperature without incurring a performance penalty due to the use of high-level exhaust energy for water spray attemperation, which can contain contaminants damaging to turbines and reduce efficiency.
Innovation Solution
The system employs a steam circuit with reheater and superheater dilution regions and conduits that allow for steam dilution without water spray attemperation, using cooler steam from upstream supply regions to dilute reheated steam, thereby avoiding the latent heat penalty and maintaining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water spray attemperation is used to control steam temperature, then steam temperature can be effectively controlled and limited, but combined cycle performance and efficiency are significantly reduced due to latent heat requirement
Solution Approach 1:
The patent introduces a steam intermediary substance (steam from the steam cycle) to replace water spray as the attemperation medium. This steam is injected into the exhaust gas stream in the HRSG to control steam temperature, eliminating the need for water vaporization and its associated latent heat penalty, thereby preserving combined cycle efficiency while achieving effective temperature control
Solution Approach 2:
The patent changes the physical state and source of the attemperation medium from liquid water to steam. By utilizing steam from the steam cycle instead of liquid water spray, the system eliminates the phase change from liquid to vapor and the associated latent heat consumption, fundamentally altering the thermodynamic parameters of the attemperation process to improve overall cycle efficiency
2Temperature
If water spray attemperation is used to control steam temperature, then steam temperature can be controlled, but contaminants in the water spray can damage the gas/steam turbine
Solution Approach 1:
The patent replaces water spray with steam as the intermediary substance for temperature control. This steam, being a clean gaseous phase substance without the contaminants present in liquid water, serves as a safe mediator that achieves temperature control without introducing harmful particles or chemicals that could damage turbine blades and components
Solution Approach 2:
The patent changes the physical state from liquid water to steam, fundamentally altering the chemical and physical properties of the attemperation medium. This phase change eliminates contaminants associated with liquid water spray, providing a clean substance that protects turbine integrity while maintaining effective temperature control capabilities
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 effectively controls steam temperature without the performance reduction associated with water spray attemperation, improving the efficiency of the combined cycle power generation system by eliminating the need for latent heat from vaporization.
Implementation Method 1
steam from at least one reheater supply region of the steam circuit attemperates steam within at least one reheater dilution region of the steam circuit
Data Source
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AI summary
A system for controlling steam temperature (100) that includes steam circuit including a reheater circuit (150), at least one reheater dilution region (155), at least one reheater dilution conduit (178), and at least one reheater supply region (141) disposed upstream of the at least one reheater dilution region (155), wherein the at least one reheater supply region (141) and the at least one reheater dilution region (155) are associated via the reheater circuit (150) and the at least one reheater dilution conduit (178).