Non-Oxygen-Consuming Energy Storage for Combined-Cycle Hot Standby
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Solution Overview
Problem
Conventional combined cycle units face challenges during standby periods, where the heat recovery boiler cools down, leading to significant thermal stress limitations when restarting the gas turbine generator, resulting in inefficient energy consumption and reduced operational safety.
Innovation Solution
A non-oxygen-consuming energy storage system is introduced, comprising an interconnecting pipe, gas inducing equipment, and a heater, which circulates and heats gas within the heat recovery boiler, maintaining components at a high temperature using excess grid electricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the combined cycle unit is shut down during standby period, then energy consumption is reduced, but the heat recovery boiler and steam turbine cool down causing thermal stress limitations when restarting
Solution Approach 1:
The system performs preliminary heating action during standby period by circulating and heating gas in the heat recovery boiler using the heater and gas inducing equipment. This maintains the boiler and steam turbine in a hot standby condition before restart, preventing thermal stress issues while avoiding continuous operation of the gas turbine.
Solution Approach 2:
The patent introduces an intermediary system consisting of the heater, gas inducing equipment, and interconnecting pipe that mediates between the shutdown state and full operation state. This intermediary system maintains thermal conditions without requiring the gas turbine to operate at low load, thus resolving the contradiction between energy saving and thermal stress prevention.
2Temperature
If the gas turbine generator operates in low-load state during standby, then the heat recovery boiler and steam turbine are maintained at high temperature, but thermal efficiency decreases and energy consumption increases
Solution Approach 1:
The patent extracts the heating function from the gas turbine system and implements it as a separate, independent system using the heater and gas inducing equipment. This allows the gas turbine to be completely shut down during standby while the extracted heating system maintains thermal conditions, eliminating the energy waste of running the gas turbine at low load.
Solution Approach 2:
The system uses the existing flue gas path and structural space of the heat recovery boiler for the standby heating function. The gas inducing equipment utilizes the existing chimney and flue gas ducts, making the standby heating system self-contained and eliminating the need for additional external energy input beyond the heater.
3Temperature
If the gas turbine generator operates in low-load state during standby, then the components remain in high-temperature state, but the operation hours increase reducing service life
Solution Approach 1:
The system performs preliminary heating action during standby period by circulating and heating gas in the heat recovery boiler using the heater and gas inducing equipment. This maintains the boiler and steam turbine in a hot standby condition before restart, preventing thermal stress issues while avoiding continuous operation of the gas turbine.
Solution Approach 2:
The patent extracts the heating function from the gas turbine system and implements it as a separate, independent system using the heater and gas inducing equipment. This allows the gas turbine to be completely shut down during standby while the extracted heating system maintains thermal conditions, eliminating the energy waste of running the gas turbine at low load.
4Temperature
If the gas turbine generator operates in low-load state during standby, then the components are kept in hot standby condition, but operating stability decreases endangering power supply safety
Solution Approach 1:
The patent introduces an intermediary system consisting of the heater, gas inducing equipment, and interconnecting pipe that mediates between the shutdown state and full operation state. This intermediary system maintains thermal conditions without requiring the gas turbine to operate at low load, thus resolving the contradiction between energy saving and thermal stress prevention.
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 system allows for rapid ramp-up of the combined cycle unit to meet emergency power demands, saves energy during standby periods, reduces start-up time and energy consumption, and enhances operational safety and efficiency.
Implementation Method 1
The heater is installed along the interconnecting pipe and is used to heat up the gas in the interconnecting pipe
Implementation Method 2
The gas inducing equipment is installed along the interconnecting pipe, is used to induce gas inside the heat recovery boiler to enter the interconnecting pipe through the chimney
Data Source
AI summary
A non-oxygen-consuming energy storage system includes: an interconnecting pipe, connecting a heat recovery boiler or a flue gas header to a chimney or its flue gas duct; a gas inducing equipment along the interconnecting pipe, inducing gas inside the heat recovery boiler to enter the interconnecting pipe through the chimney and then enter the heat recovery boiler; and a heater along the interconnecting pipe and heating up the gas in the interconnecting pipe, and using electricity or other non-oxygen-consuming heating devices as a heat source. Thereby, the gas in the heat recovery boiler is circulated and heated up by the system, and pipelines and components of each unit are kept in a hot standby condition, thus under an emergency power demand on the power grid, the combined cycle unit can rapidly ramp up its load to meet the demand, and can also reduce energy consumption during start-up stage.