Steam Generator Attemperators for Thermal Stress Protection

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Solution Overview

Problem

Existing steam generator systems lack effective protection against rapid temperature changes, leading to thermal stress on the steam turbine and oversized installations, with existing attemperator solutions offering limited adjustability and efficiency during startup or power output changes.

Innovation Solution

A steam generator system with multiple attemperators strategically placed within the heat exchanger piping and a control system using fluid distribution valves to manage cooling fluid flow, allowing precise temperature control and rapid response to temperature changes, thereby protecting the piping and enhancing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an attemperator is arranged in front of the superheater to protect the steam turbine, then the steam turbine is protected against thermal stress, but the piping of the superheater and the steam generator itself remains unprotected and experiences high thermal stress

Engineering Contradiction:
Improveprotection of steam turbineVSAvoidthermal stress on superheater piping
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention divides the single attemperator function into multiple segments by arranging several attemperators at different locations within the steam generator (in the hot gas path and/or in the steam path). This segmentation allows each attemperator to protect specific sections of piping, ensuring comprehensive protection throughout the system rather than only at the turbine inlet.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If an attemperator is arranged between the second last heat exchanger and the superheater, then the superheater and its piping experience less thermal stress, but the temperature adjustability of the hot steam at the superheater output becomes poor

Engineering Contradiction:
Improvethermal stress on superheaterVSAvoidtemperature adjustability
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The invention implements dynamic temperature control by positioning attemperators at multiple locations along the steam generation path, enabling flexible and rapid adjustment of steam temperature at different stages. This dynamic arrangement allows the system to adapt quickly to changing load conditions and maintain optimal temperature control, unlike fixed-position attemperators that suffer from poor adjustability.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If a single attemperator is used with sensitive control, then the steam temperature can be controlled, but the control becomes overly sensitive requiring larger safety margins between actual and admissible temperature changes

Engineering Contradiction:
Improvesteam temperature controlVSAvoidresponse range for temperature changes
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The invention segments the temperature control function across multiple attemperators located at different positions in the steam generator. This segmentation distributes the control burden, reducing the sensitivity of each individual control valve while maintaining overall precise temperature control. The distributed arrangement allows for more gradual and stable temperature adjustments without requiring excessive safety margins.

Inventive Principle:
Principle #1Segmentation

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

The system provides improved adjustability and protection against thermal stress, reducing the risk of overheating and increasing the lifetime of components, while maintaining efficiency and responsiveness during power output changes.

Implementation Method 1

The attemperator is used to inject water into the hot steam after the superheater. Thus, leads to a reduction of the temperature of the hot steam delivered to the steam turbine.

Methodology Applied
Scientific EffectHeat transfer: Convection

Implementation Method 2

a steam generator is used to convert the hot gas from the gas turbine into hot steam for the steam turbine

Methodology Applied
Scientific EffectHeat transfer: Convection

Data Source

PatentEP4214405B1Steam generator with attemperators
Publication Date: 2024.10.16 NEM ENERGY
  • EP4214405B1 patent drawingFigure 1
  • EP4214405B1 patent drawingFigure 2
  • EP4214405B1 patent drawingFigure 3

AI summary

The invention is about an advantage steam generator (01) and a steam generation system with an arrangement of heat- exchangers (11) within a hot gas path (02). To protect the facilities and to increase the efficiency at least at the output of several heat-exchangers (11) an attemperator (22) is arranged, wherein each of them (22) is connected via a fluid distribution valve (23) with a distribution piping (21).