Steam Turbine Cooling Rate Control via Feedback

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Solution Overview

Problem

Current steam turbine cooling methods, particularly 'forced cooling,' are inefficient and time-consuming, often resulting in wasted fuel due to limited exploitation of cooling freedoms and lack of real-time temperature gradient feedback control during power operation.

Innovation Solution

A method that involves determining and regulating the steam turbine's cooling rate by comparing the actual and specified cooling rates, with an automation system ensuring the steam generator operates to maintain the cooling rate within predetermined limits, utilizing finite element methods, component temperature considerations, and feedback control to optimize cooling within design limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rigid ramps are used to reduce steam temperature during operation, then the steam turbine design limits are not exceeded, but the cooling process time is extended and fuel efficiency is reduced

Engineering Contradiction:
Improvesteam turbine design limits complianceVSAvoidcooling process time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements a feedback control system that continuously monitors the actual cooling rate of the steam turbine and compares it with the predetermined cooling rate. The steam generator is operated to adjust the steam temperature based on this comparison, ensuring the actual cooling rate substantially corresponds to the predetermined rate. This closed-loop feedback mechanism allows dynamic adjustment of cooling parameters to optimize both time and safety compliance.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transitions from static rigid ramps to dynamic cooling rate control. The predetermined cooling rate can be adapted based on real-time conditions, allowing the system to optimize the cooling process dynamically. The automation system continuously adjusts operating parameters to maintain the desired cooling rate, enabling more flexible and efficient cooling compared to fixed ramp schedules.

Inventive Principle:
Principle #15Dynamics

2Reliability

If rigid ramps are used to reduce steam temperature during operation, then the steam turbine design limits are not exceeded, but fuel consumption increases due to limited exploitation of cooling freedoms

Engineering Contradiction:
Improvesteam turbine design limits complianceVSAvoidfuel consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The feedback control system monitors the actual cooling rate and adjusts the steam generator operation accordingly. By comparing actual versus predetermined cooling rates in real-time, the system can optimize fuel consumption by only applying cooling when and where needed, rather than following fixed rigid ramps that may over-cool or waste fuel during periods when natural cooling suffices.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the cooling parameters from fixed rigid ramps to dynamically adjusted predetermined cooling rates. The automation system can modify steam temperature, pressure, and flow parameters based on real-time cooling rate measurements, allowing optimal exploitation of cooling freedoms and minimizing fuel consumption while maintaining safety compliance.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If feedback control of temperature gradient is implemented during power operation, then cooling process is accelerated, but system complexity increases

Engineering Contradiction:
Improvecooling process speedVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements feedback control by continuously determining the actual cooling rate and comparing it with the predetermined cooling rate during power operation. The automation system uses this feedback to adjust the steam generator operation in real-time, accelerating the cooling process while maintaining control within acceptable complexity through automated algorithms.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-monitoring and self-adjustment of cooling parameters. The automation system automatically determines cooling rates, compares them with targets, and adjusts operating parameters without requiring constant manual intervention, thereby accelerating cooling while managing complexity through autonomous operation.

Inventive Principle:
Principle #25Self-service

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 approach accelerates the steam turbine cooling process while ensuring safe operation within design limits, optimizing fuel usage by dynamically adjusting cooling rates based on real-time conditions and component temperatures.

Implementation Method 1

For cooling, it is common practice to cool the steam turbine using so-called 'forced cooling.' Forced cooling essentially comprises three phases.

Methodology Applied
Scientific EffectForced cooling: Forced Convection

Implementation Method 2

the cooling rate takes into account the temperature of the components, such as the housing and the rotor of the steam turbine

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3280884B1Method for cooling a steam turbine
Publication Date: 2021.07.28 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP3280884B1 patent drawingFigure 1

AI summary

The invention relates to an automation system that determines the theoretical maximum rate of cooling of a steam turbine (2) and operates a steam generator (6) in such a way that the thermal energy of the steam does not exceed nor drop below the predefined rate of cooling.