Steam Turbine Warming System Decoupling Start-Up Time
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Solution Overview
Problem
Current steam turbine warming systems are limited by their coupling with other major equipment in power plants, leading to prolonged start-up times and reduced flexibility, especially when using steam pre-warming methods that restrict flow rates and increase heat-up times.
Innovation Solution
A warming system for steam turbines featuring a closed loop arrangement with a makeup line, recycle line, gas moving device, and heater, along with a controller to regulate flow rates and moisture content, allowing for independent pre-warming and drying without relying on other equipment start-ups, and incorporating heat recuperation for energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If steam is used to pre-warm the turbine during rolling, then the turbine can be warmed up, but the flow rate of pre-warming medium is restricted which increases heat-up time
Solution Approach 1:
The patent introduces a separate pre-warming medium system that is independent of the main steam system. This intermediary system allows pre-warming without the constraints of the main steam flow rate limitations, thereby reducing heat-up time while still achieving the required temperature increase.
Solution Approach 2:
The patent divides the warming process into separate stages and systems: a dedicated pre-warming stage using a separate medium, and the main operational steam stage. This segmentation allows the pre-warming phase to operate independently with optimized flow rates, reducing overall heat-up time without affecting main steam system performance.
2Productivity
If high flow rate of pre-warming medium is used through nominal steam path, then warming efficiency is improved, but the turbine may roll off the turning gear due to premature acceleration
Solution Approach 1:
The patent uses a separate pre-warming medium as an intermediary that allows high flow rates for efficient warming without directly affecting the turbine rotor dynamics in the same way main steam would. This intermediary system achieves warming efficiency while maintaining turbine stability on the turning gear.
Solution Approach 2:
The patent extracts the pre-warming function from the main steam path and implements it as a separate system. This extraction allows the pre-warming medium to be optimized for heating efficiency without the constraints of maintaining turbine stability, while the main steam system remains unaffected.
3Temperature
If steam pre-warming is used, then the turbine can be warmed up, but it couples the pre-warming process with other major equipment start-up which prolongs overall start-up time
Solution Approach 1:
The patent extracts the pre-warming function from the main steam generation system and implements it as an independent system with its own heating source. This allows the turbine to be pre-warmed independently of the gas turbine or main steam system start-up sequence, significantly reducing overall plant start-up time.
Solution Approach 2:
The patent performs the pre-warming action independently and in advance of the main steam system start-up. By decoupling these operations, the turbine can be prepared in advance without waiting for other equipment, enabling parallel operations that reduce total start-up time.
4Reliability
If lower pre-warming medium flow rate is used, then turbine stability is maintained, but heat-up time is increased
Solution Approach 1:
The patent introduces a separate pre-warming medium as an intermediary that allows higher flow rates without compromising turbine stability. This intermediary system enables faster warming (improved productivity) while the turbine remains stable, resolving the trade-off between warming speed and stability.
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 enables faster and more reliable start-ups, reduces energy consumption, and allows for flexible operation by decoupling the warming process from other equipment, improving the overall efficiency and reliability of steam turbine operations.
Implementation Method 1
A heater is provided in either the first makeup line or recycle line to heat the first warming gas before entering the steam turbine
Implementation Method 2
The gas moving device, located in either for first makeup line or recycle line, is the motive means for moving the warming gas through the warming system
Implementation Method 3
a first steam turbine, for expanding steam
Data Source
Figure 1
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Figure 3
AI summary
The invention relates to a warming arrangement having a warming system (30a) for warming a steam turbine (20a). The warming system (30a) has a makeup line (36a), and recycle line (37a) fluidly connected to the steam turbine (20a). A gas moving device (41 a) and a heater (43a) are located in either of these two lines. The warming system (30a) further includes a pressure measurement device (53a) that is configured and arranged to determine a gauge pressure in the steam turbine (20a) as well as a controller (50). The controller is configured to control a flow rate of the warming gas through the steam turbine (20a), based on the pressure measurement device (53a).