Superheater Isolation Valve for Solar Receiver Shutdown Heat Retention
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Solution Overview
Problem
Solar-thermal receiver systems experience rapid pressure and temperature loss upon shutdown due to direct connection of superheaters to the evaporator section, leading to condensation of steam and wastage of high-quality, chemically treated water, which prolongs startup time and reduces operational efficiency.
Innovation Solution
A superheater isolation valve is positioned between the steam drum or vertical separator and the superheater, acting as a stop valve or flow control valve with zero leakage, which closes at the end of the day to prevent steam transfer and maintain pressure and temperature, controlled by a processor that detects solar flux and system state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the superheater is directly connected to the evaporator section, then steam flow is maintained during operation, but pressure and temperature are rapidly lost during shutdown due to condensation
Solution Approach 1:
The system is divided into two independent sections by the isolation valve: the evaporator section and the superheater section. This segmentation allows the superheater to be isolated from the evaporator during shutdown, preventing the pressure and temperature loss that occurs when steam condenses in the connected superheater. During operation, the valve is open to maintain steam flow, but during shutdown, it closes to preserve the thermal state in the evaporator section.
Solution Approach 2:
The superheater isolation valve acts as an intermediary element between the evaporator section and the superheater. It controls the steam flow between these two sections, allowing operation when open and preventing energy loss when closed. The valve mediates the conflict between maintaining operational steam flow and preventing shutdown condensation losses.
2Reliability
If steam condenses in the superheater during shutdown, then pressure equalizes with ambient, but high-quality treated water is wasted and startup time is prolonged
Solution Approach 1:
By segmenting the system with the isolation valve, the superheater section is separated from the evaporator section during shutdown. This prevents treated water from the evaporator section from flowing into and condensing in the superheater, thereby eliminating the wastage of high-quality chemically treated water while maintaining system stability.
3Duration of action of moving object
If the receiver shuts down, then operational cycle ends, but pressure and temperature decay rapidly prolonging the next startup time
Solution Approach 1:
The isolation valve closes automatically when the receiver shuts down, performing a preliminary action to prevent pressure and temperature decay before the next startup. By isolating the superheater section during shutdown, the evaporator section maintains its thermal state, thereby reducing the time required to reach operational parameters during the next startup.
4Loss of energy
If a superheater isolation valve is added, then pressure and temperature loss is reduced, but device complexity increases
Solution Approach 1:
The superheater isolation valve serves as a simple intermediary component that effectively reduces thermal energy loss during shutdown. While it does add a valve and control system, the principle of using a straightforward isolation mechanism rather than complex active heating or insulation systems keeps the added complexity minimal while achieving significant energy preservation.
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
The superheater isolation valve significantly reduces pressure and temperature decay during shutdown, preserving heat and pressure, allowing for faster system startup and reducing the wastage of treated water, thereby enhancing electricity generation and extending the startup time.
Implementation Method 1
the steam volume present in the superheater condenses due to a heat transfer to the ambient. Accordingly, pressure in the superheater typically drops, and these pressure drops result in a steam flow into the superheater
Implementation Method 2
the steam volume present in the superheater condenses due to a heat transfer to the ambient
Implementation Method 3
the steam volume present in the superheater condenses due to a heat transfer to the ambient via convection, radiation, and conduction losses
Implementation Method 4
the steam volume present in the superheater condenses due to a heat transfer to the ambient via convection, radiation, and conduction losses
Implementation Method 5
the steam volume present in the superheater condenses due to a heat transfer to the ambient via convection, radiation, and conduction losses
Implementation Method 6
the pressure and temperature losses prolong or otherwise delay the start of an efficient use of the receiver startup time
Data Source
AI summary
A solar-thermal receiver with a superheater isolation valve is disclosed. The superheater isolation valve is positioned so as to impede the transfer of steam from a steam drum or vertical separator into a superheater. The decays in temperature and pressure, within components of a solar-thermal receiver system that may occur throughout the shutdown period of a solar-thermal receiver, may be reduced or minimized.