Steam Generator Cleaning Control via Thermal Feedback

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Solution Overview

Problem

Steam generators face inefficiencies and increased maintenance costs due to boiler fouling from ash-forming substances, requiring precise and timely cleaning while minimizing power losses and wear, especially with fluctuations in electricity demand and renewable energy inputs.

Innovation Solution

A method for controlling steam generator output using steam and/or water-powered cleaning devices, involving monitoring status variables, creating forecasts for effectiveness and load, and optimizing cleaning schedules to prevent excessive wear and unscheduled downtime, ensuring optimal power yield and effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If steam and water-powered cleaning devices are used to clean heating surfaces during operation, then boiler fouling is removed and heat transfer efficiency is improved, but power generation capacity is reduced due to steam extraction and heat loss

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidpower generation capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic control of cleaning device operation by continuously monitoring heating surface temperature distribution and adjusting cleaning timing and intensity accordingly. The system determines optimal cleaning moments when temperature deviations indicate fouling, enabling adaptive cleaning that responds to actual boiler conditions rather than following fixed schedules, thus minimizing impact on power generation while maintaining heat transfer efficiency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback control through continuous monitoring of heating surface temperatures using thermal imaging or temperature sensors. The measured temperature distribution is fed back to the control system, which compares it against reference values and triggers cleaning operations only when deviations exceed predetermined thresholds, ensuring cleaning is performed only when necessary and optimizing the balance between cleanliness and power generation

Inventive Principle:
Principle #23Feedback

2Reliability

If cleaning is performed frequently to maintain heating surface effectiveness, then heat transfer efficiency is maintained, but wear and tear on cleaning devices and heating surfaces increases

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidservice life of cleaning devices and heating surfaces
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent uses thermal imaging and temperature monitoring to detect early signs of fouling before they severely impact heat transfer. By identifying temperature anomalies in advance, the system can schedule cleaning operations at optimal moments, preventing the need for frequent emergency cleaning and reducing cumulative wear on both heating surfaces and cleaning devices

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the operational parameters of cleaning devices based on monitored conditions. Instead of using constant cleaning intensity, the system adjusts water or steam flow rates, pressure, and duration of cleaning pulses according to the severity of fouling detected, thereby achieving effective cleaning with minimal wear when fouling is light and using more intensive cleaning only when necessary

Inventive Principle:
Principle #35Parameter changes

3Reliability

If water lance blowers are used to clean radiant heating surfaces, then deposits are removed, but thermal stress on wall areas increases and cleaning precision is difficult to control

Engineering Contradiction:
Improvedeposit removal effectivenessVSAvoidthermal stress on boiler walls
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality control by using thermal imaging to identify specific localized areas of fouling on heating surfaces. The cleaning system then directs water or steam jets precisely at these identified hot spots rather than uniformly cleaning entire surfaces, concentrating cleaning energy only where deposits exist and minimizing unnecessary thermal stress on clean areas of the boiler walls

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent replaces purely mechanical impact-based cleaning with a thermally-guided system. Instead of relying on high-velocity water jets alone, the system uses thermal field information from infrared imaging to guide and modulate the mechanical cleaning action, substituting blind mechanical force with intelligent, temperature-guided cleaning that reduces unnecessary thermal and mechanical stress

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If cleaning is delayed to avoid power losses, then power generation capacity is maintained, but deposits accumulate and cause permanent encrustations that impair heat transfer

Engineering Contradiction:
Improvepower generation capacityVSAvoidheat transfer efficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements continuous feedback monitoring of heating surface temperatures to detect the onset of fouling accumulation. When temperature deviations indicate that deposits are forming and beginning to impact heat transfer, the system automatically triggers cleaning operations, preventing the progression to severe encrustations while avoiding unnecessary cleaning during normal operation, thus maintaining both power generation and heat transfer efficiency

Inventive Principle:
Principle #23Feedback

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 allows for precise and timely cleaning, optimizing power generation and heat transfer, reducing wear and tear, and aligning cleaning processes with electricity demand fluctuations to minimize losses and extend steam generator availability.

Implementation Method 1

cleaning the combustion chamber walls involves a certain thermal stress on the wall areas to be cleaned

Methodology Applied
Scientific EffectThermal stress: Thermal Shock

Implementation Method 2

The use of water to clean the boiler walls/radiant heating surfaces cools the boiler walls and extracts heat from the system

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 3

The steam required for cleaning is usually extracted from the systems as process steam. If cleaning is not carried out in good time or much too late, deposits that can be traced back to melting, sintering of the deposits or chemical processes, lead to permanent encrustations

Methodology Applied
Scientific EffectSteam tapping:

Implementation Method 4

deposits that can be traced back to melting, sintering of the deposits or chemical processes, lead to permanent encrustations that significantly impair the heat transfer and the efficiency of the systems

Methodology Applied
Scientific EffectHeat transfer impairment: Thermal Insulation

Implementation Method 5

The use of water to clean the boiler walls/radiant heating surfaces cools the boiler walls and extracts heat from the system that would otherwise be used to generate electricity or use heat

Methodology Applied
Scientific EffectHeat extraction: Heat Sink

Data Source

PatentEP3080514B1Method for regulating the output of steam generators for generating power and/or providing heat
Publication Date: 2018.02.28 RWE POWER AKTIENGESELSCHAFT
  • EP3080514B1 patent drawingFigure 1
  • EP3080514B1 patent drawingFigure 2
  • EP3080514B1 patent drawingFigure 3

AI summary

The invention relates to a method for regulating the output of steam generators for generating power and/or providing heat while taking into consideration the use of steam and/or water-powered cleaning devices while the steam generator is being operated. The method has the step of monitoring steam generator state variables which allow direct or indirect conclusions on the effectiveness and/or the dirt-accumulation state of heating surfaces of the steam generator. The method further comprises the steps of generating an effectiveness prediction using the measured and/or ascertained state variables, generating a load prediction as a function of the power demand and/or the heat demand, generating a prediction of the expected available maximum output of the steam generator as an availability prediction and as a function of the surrounding temperature and/or the fuel quality, and determining an optimal cleaning time as a function of the effectiveness prediction. A target cleaning process which is to be initiated according to the effectiveness prediction is delayed or prevented and/or shortened or prolonged and/or intensified or weakened depending on the load prediction and the availability prediction with the condition that a specified minimum effectiveness of the heating surfaces of the steam generator is not undershot and/or a specified maximally permissible dirt accumulation of the surfaces is not exceeded.