Thermal Storage Pressure Vessel Steam Demand
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Solution Overview
Problem
Existing steam supply systems for industrial plants are inefficient in accommodating variations in steam demand, as they require large turndown ratios and often rely on fossil fuel-based boilers. Additionally, these systems lack efficient methods for thermal energy storage and supply.
Innovation Solution
A method and apparatus for thermal energy storage and supply that involves providing subcooled water to a pressure vessel, heating it with an electrically-powered heater to create saturated liquid water and steam at a variable storage pressure, and selectively discharging steam to meet thermal energy demands, thereby managing pressure and energy efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a burner-powered boiler is used to generate steam, then steam supply is provided, but the system is inefficient when accommodating variations in steam demand due to large turndown ratios
Solution Approach 1:
The system pre-heats water using an electrical heater during periods of low steam demand to raise the water temperature and pressure in the accumulator, preparing thermal energy in advance so that when steam demand increases, the pre-heated water can rapidly generate steam without requiring the boiler to operate inefficiently at low load
Solution Approach 2:
The system changes the operational parameters by using an electrical heater instead of a burner to heat water, allowing precise control of heating power and temperature. This enables the accumulator to store thermal energy at variable temperatures and pressures, improving the system's ability to respond to varying steam demands while maintaining high efficiency
2Productivity
If an accumulator is added to accommodate steam demand variations, then steam supply stability is improved, but the system complexity increases
Solution Approach 1:
The accumulator serves multiple functions: it acts as a thermal energy storage device, a pressure regulation vessel, and a steam generation chamber. By combining these functions in a single component, the system avoids needing separate devices for each function, thereby reducing overall system complexity while maintaining the ability to respond to steam demand variations
3Loss of energy
If electrical heating elements are used instead of fossil fuel boilers, then efficiency with variable power output is improved, but energy input requirements increase
Solution Approach 1:
The system uses periodic action by operating the electrical heater during specific periods when steam demand is low or when electrical energy is more readily available or cheaper. The heater cycles on and off based on the thermal energy level in the accumulator, maintaining efficient operation while managing overall energy consumption patterns
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 allows for efficient storage and supply of thermal energy, accommodating variable steam demands while reducing energy input during depletion periods and optimizing energy use during recharge periods, thus enhancing the overall efficiency of the steam supply system.
Implementation Method 1
heating liquid water within the pressure vessel using an electrically-powered heater
Implementation Method 2
providing subcooled water to a pressure vessel; heating liquid water within the pressure vessel so that the vessel contains saturated liquid water and steam at a variable storage pressure
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
There is disclosed a thermal energy storage and supply method comprising: providing subcooled water to a pressure vessel (110); heating liquid water within the pressure vessel using an electrically-powered heater so that the vessel contains saturated liquid water and steam at a variable storage pressure; controlling the heater (112) to raise the storage pressure to a peak storage pressure of at least 2 MPa; and selectively discharging steam from an outlet of the pressure vessel to a thermal load (130, 40), in response to a thermal energy demand, such that during a depletion period the storage pressure reduces by at least 1 MPa from the peak storage pressure.