ORC Buffer for Steam Extraction Turbine Rotor Stability
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Solution Overview
Problem
Combined Heat and Power (CHP) systems with extraction condensation turbines face operational challenges due to fluctuating heat and electricity demands, leading to limited flexibility and increased risks from variable steam extraction, which affects rotor dynamics and axial thrust, necessitating costly optimizations and potentially resulting in reduced electricity revenue.
Innovation Solution
Integration of an Organic Rankine Cycle (ORC) process in parallel with the heating condenser of the district heating network, allowing for constant steam extraction and flexible power generation by preheating and evaporating a working medium, such as R1232zd, R1336, or R1224, to manage variable heat demand and maintain stable steam supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If steam extraction is increased to meet heating demand, then heat supply capability is improved, but rotor dynamics stability deteriorates and axial thrust variability increases
Solution Approach 1:
The system dynamically adjusts the distribution of extracted steam between the heating condenser and ORC system based on real-time operating conditions. The ORC system acts as a flexible buffer that can absorb steam extraction variations, allowing the heating condenser to maintain stable operation while meeting varying heating demands. This dynamic allocation resolves the contradiction by enabling high steam extraction for heating without compromising rotor dynamics stability.
Solution Approach 2:
The ORC system serves as an intermediary between the steam extraction and the heating condenser. By introducing this intermediate system, the patent decouples the direct relationship between steam extraction quantity and heating condenser operation. The ORC system absorbs the variability and stabilizes the steam supply to the heating condenser, thereby protecting rotor dynamics while enabling flexible heat supply.
2Reliability
If steam extraction is limited to ensure turbine safety, then rotor dynamics stability is maintained, but heat supply flexibility deteriorates
Solution Approach 1:
The patent segments the steam extraction function into two independent pathways: one leading to the heating condenser and another to the ORC system. This segmentation allows each subsystem to operate within its optimal safety margins while collectively providing flexible heat and power supply. The ORC system handles variable demand fluctuations, enabling the heating condenser to operate safely at stable extraction levels.
Solution Approach 2:
The system changes the operational parameters by introducing a second steam utilization pathway through the ORC system. This parameter change transforms the single-constraint problem into a multi-objective optimization where both heating demand and turbine safety can be satisfied simultaneously. The ORC system operates with different thermal parameters, allowing flexible adaptation to varying heating demands without compromising turbine safety.
3Device complexity
If CHP system operates with fixed heat-power coupling, then system simplicity is maintained, but responsiveness to electricity market fluctuations deteriorates
Solution Approach 1:
The ORC system provides multi-functionality by simultaneously serving power generation and heat supply functions. It can operate in different modes: generating electricity from steam extraction, providing thermal energy to the heating network, or adjusting its operation to balance both demands. This universal capability enables the CHP system to respond flexibly to electricity market fluctuations while maintaining a relatively simple overall structure.
Solution Approach 2:
The system introduces dynamic operation capabilities through the ORC component, which can rapidly adjust its steam consumption and power output in response to market signals. This dynamic behavior contrasts with the fixed coupling of traditional CHP systems, enabling real-time optimization of heat-power generation based on electricity prices and market conditions while keeping the base system architecture simple.
4Productivity
If extraction condensation turbine is optimized for specific operating cases, then performance at design point is improved, but adaptability to varying conditions deteriorates
Solution Approach 1:
The ORC system acts as a buffer that absorbs the variability and allows the extraction condensation turbine to operate consistently at or near its design point. By taking up the fluctuations in steam demand through the ORC system, the turbine maintains stable operating conditions, preserving its optimized efficiency while the overall system adapts to varying heating and power demands.
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 enhances the flexibility and uniformity of steam turbine operation, reduces operational risks, and increases efficiency by automatically adjusting to heating demands, enabling more effective power generation and heat distribution while minimizing costs and environmental impact.
Implementation Method 1
a device for preheating and evaporating a working medium of an Organic Rankine Cycle (ORC) is arranged in the steam line
Implementation Method 2
preheating and evaporating a working medium of an Organic Rankine Cycle (ORC)
Implementation Method 3
The generated and exergetically high-quality steam is expanded within the turbine to a pressure of less than 10 bar
Implementation Method 4
The generated and exergetically high-quality steam is expanded within the turbine to a pressure of less than 10 bar and then conducted via the low-pressure blading into a condenser
Data Source
Figure 1
AI summary
The invention relates to a system (1) comprising a steam extraction condensing turbine (2) with a steam extraction port (3) and a steam line (4) branching off from the steam extraction port (3), in which a heating condenser (5) of a district heating network (6) is arranged, wherein a device (7) for preheating and evaporating a working medium of an Organic Rankine Cycle (8) is further arranged in the steam line (4) in parallel to the heating condenser (5) of the district heating network (6). The invention further relates to a method for operating a system (1) comprising a steam extraction condensing turbine (2) with a steam extraction port (3).