Steam Turbine Loading Control via Exhaust Temperature Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional combined cycle power systems face limitations in steam turbine loading due to constraints such as stress, differential expansion, and clearances, which restrict the rate of steam consumption and increase air emissions, fuel consumption, and starting time during startup.
Innovation Solution
A method and system for controlling the ramping rate of steam flow and steam temperature in a steam turbine using a defined algorithm that establishes a proportional relationship between steam flow and temperature ramping, dependent on turbine exhaust temperatures, allowing for efficient steam consumption without violating turbine constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the steam turbine loading rate is increased to maximize power generation during startup, then productivity is improved, but the steam turbine constraints (stress, differential expansion, clearances) are violated due to excessive moisture
Solution Approach 1:
The patent applies dynamics by making the steam flow ramping rate variable rather than fixed. The control system dynamically adjusts the ramping rate based on real-time turbine exhaust temperature measurements, allowing the system to operate at maximum power generation capacity when conditions permit while automatically reducing the rate when approaching moisture constraints, thus resolving the contradiction between productivity and reliability
Solution Approach 2:
The patent changes the parameter of steam flow ramping rate based on turbine exhaust temperature. By establishing a relationship where the allowable ramping rate decreases as exhaust temperature decreases (approaching saturation), the system optimizes power generation while preventing excessive moisture formation that would violate turbine constraints
2Reliability
If traditional low load limits and restricted loading rates are applied to control steam temperature, then steam turbine constraint compliance is maintained, but air emissions increase, fuel consumption increases, and starting time increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing the relationship between turbine exhaust temperature and maximum allowable steam flow ramping rate. This allows the control system to proactively adjust loading rates before constraint violations occur, enabling faster startup and higher power generation while maintaining compliance, thus resolving the contradiction between reliability and productivity
Solution Approach 2:
The patent implements feedback control by continuously measuring turbine exhaust temperature and using this information to adjust the steam flow ramping rate. This closed-loop control enables the system to maintain constraint compliance while optimizing for maximum power generation and minimum emissions, addressing the contradiction between reliability and startup efficiency
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Systems 10 and methods for loading a steam turbine 14 are provided. A method may include: receiving a turbine loading factor; receiving a current steam turbine exhaust temperature; determining a steam flow ramping rate parameter 205 and a steam temperature ramping rate parameter 210 based at least in part on the turbine loading factor and the current steam turbine exhaust temperature, wherein the steam flow ramping rate parameter and the steam temperature ramping rate parameter are determined based at least in part on an inverse relationship between the steam flow ramping rate parameter and the steam temperature ramping rate parameter. The method may further include controlling at least one of: (a) steam flow to the steam turbine based at least in part on the steam flow ramping rate parameter; or (b) steam temperature to the steam turbine 14 based at least in part on the steam temperature ramping rate parameter 210.