Black Start Power Plant Using Heated Compressed Air
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Solution Overview
Problem
Combined cycle power plants face challenges in maintaining operational autonomy during a 'black start' scenario and in utilizing the full potential of their pressure storage systems, as they require pressurized fluid at a specific pressure level and lack internal means for immediate startup after a power outage.
Innovation Solution
The integration of a gas turbine group with a steam cycle and a pressure accumulator system, where compressed air from the storage system is routed through a heat exchanger to generate high-quality air for operating the storage fluid expansion machine, enabling immediate startup of the gas turbine group using the generated electricity, and the use of tube burners to supplement heat when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If compressed air is stored in the pressure accumulator system, then high performance can be achieved during operation, but the system cannot perform black start autonomously after a power outage
Solution Approach 1:
The patent applies preliminary action by pre-heating the compressed air in the pressure accumulator system using the heat exchanger during normal operation, so that when a black start is needed, the air is already at the required temperature (approx. 550°C) to immediately drive the storage fluid expansion machine and generate electricity for autonomous startup, eliminating the need for external power sources
Solution Approach 2:
The system applies self-service by using its own internal resources - the stored compressed air and the heat exchanger's residual heat capacity - to generate the electricity needed for black start without requiring external power sources. The heat exchanger serves dual purposes: normal power generation and black start preparation
2Temperature
If the heat exchanger is used to heat compressed air for power generation, then high-quality working air is available, but the heat potential may be insufficient for immediate black start requirements
Solution Approach 1:
The heat exchanger is designed to pre-heat the compressed air to high temperatures (approx. 550°C) during normal operation, preparing it in advance for black start scenarios. This preliminary heating ensures that when needed, the air has sufficient thermal energy to drive the expansion machine immediately
Solution Approach 2:
The system utilizes parameter changes by varying the thermal state of the compressed air - storing it at high pressure (at least 60 bar) and heating it to high temperature (approx. 550°C) in the heat exchanger, thereby transforming it into high-quality working air with the necessary energy parameters for immediate power generation during black start
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 configuration ensures rapid normalization of power supply after a blackout by enabling autonomous startup of the power plant, as the system can initiate a 'black start' without delay, addressing the limitations of existing designs by leveraging the heat potential of the pressure accumulator system and providing sufficient thermal and pressure potential for starting the gas turbine.
Implementation Method 1
part of the air stored there is routed through the heat exchanger arranged on the outflow side. This heat exchanger, which is part of the operation of the power plant in the recuperative mode via the pressure accumulator system, has an inherent heat potential, so that the air taken from the pressure accumulator, which usually at a pressure of at least 60 bar at a temperature of approx. 30°C is available, after flowing through it, is heated to approx. 550°C
Implementation Method 2
the air taken from the pressure accumulator... is available, after flowing through it, is heated to approx. 550°C. However, the pressure of this thermally treated air still remains high, usually of the order of about 55 bar. Consequently, high-quality working air is available, which is particularly suitable for directly operating the storage fluid expansion machine belonging to the power plant
Data Source
Figure 1
AI summary
The invention relates to a power plant, which essentially consists of a gas turbine assembly (1), a compressed air reservoir (16) and an air turbine (2) that is equipped with at least one generator (4). During the operation of said power plant, compressed air (23), which is drawn from the compressed air reservoir (16), is guided through a heat exchanger (9) that is active on the outflow side of the gas turbine assembly (1) and is thermally treated. Said compressed air (24) is subsequently supplied to the air turbine (2). According to the invention, during a black-out or other stoppage of the power plant, the electric energy that can be obtained in the air turbine (2) by means of the thermally treated compressed air (24) is used to start up the gas turbine assembly (1) via a power line (25).