Thermodynamic Slag Modeling for Biogenic Fuel Contamination

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Solution Overview

Problem

Power plants face challenges with slagging and contamination in combustion chambers when using biogenic fuels, leading to reduced operating time and potential damage, and existing solutions are costly or ineffective.

Innovation Solution

A method that determines a model composition of substitute fuels using thermodynamic modeling to assess and manage slag formation and contamination risk, allowing for the safe operation of power plants with high biogenic fuel proportions without the need for expensive additives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If biogenic substitute fuels are burned in a power plant combustion chamber, then the use of renewable energy sources is improved, but slagging and contamination of the combustion chamber increases

Engineering Contradiction:
Improveuse of biogenic fuelVSAvoidslagging and contamination
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The method performs preliminary thermodynamic modeling and viscosity calculation of slag composition before actual combustion occurs. By calculating the viscosity of model slag at different temperatures and determining contamination risk in advance, the system can predict whether a given biogenic fuel composition will cause excessive slagging, and adjust the fuel mix or combustion parameters beforehand to prevent contamination.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system establishes a feedback loop where contamination risk is continuously assessed based on fuel composition analysis. The measured or analyzed composition of biogenic fuels is fed into the thermodynamic model to recalculate slag viscosity and contamination risk, which then feeds back to control the fuel mixing ratio or combustion chamber operations to maintain acceptable contamination levels.

Inventive Principle:
Principle #23Feedback

2Reliability

If the amount of biogenic fuel is increased to reduce fossil fuel use, then environmental sustainability is improved, but cleaning intervals of the combustion chamber are shortened

Engineering Contradiction:
Improveenvironmental sustainabilityVSAvoidcleaning interval
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

Before increasing biogenic fuel usage, the method performs preliminary thermodynamic analysis to calculate the viscosity of resulting slag and assess contamination risk. This advance calculation allows operators to determine the maximum safe proportion of biogenic fuel that can be burned without causing excessive slagging, thereby extending cleaning intervals while maintaining environmental sustainability goals.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts combustion parameters such as temperature profile, fuel mixing ratio, and excess air coefficient based on calculated slag viscosity and contamination risk. By changing these parameters in response to fuel composition variations, the system optimizes the balance between utilizing biogenic fuels and minimizing slagging that would require frequent cleaning.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If expensive additives are burned to change slag formation and composition, then slagging is reduced, but operating costs increase

Engineering Contradiction:
Improveslagging reductionVSAvoidoperating cost
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

Instead of physically adding expensive additives to modify slag composition, the method creates a virtual model of the slag composition using thermodynamic calculations based on fuel analysis data. This digital copy of the slag behavior allows prediction and optimization of combustion parameters to achieve desired slag properties without the cost of actual additive materials.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The invention replaces the mechanical/chemical approach of adding physical substances (additives) with a computational approach using thermodynamic modeling and viscosity calculation. The system substitutes expensive material additions with inexpensive computational analysis and parameter optimization, achieving slagging control through intelligence rather than material input.

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

4Use of energy by moving object

If the composition of substitute fuels is varied to optimize energy use, then renewable energy utilization is improved, but prediction of contamination risk becomes more difficult

Engineering Contradiction:
Improverenewable energy utilizationVSAvoidcomposition analysis complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The method employs a universal thermodynamic modeling approach that can handle any combination of biogenic fuels and their varying compositions. The same computational framework and viscosity calculation methodology work regardless of fuel source variations, providing a multi-functional tool that simplifies rather than complicates the analysis of diverse fuel mixtures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system focuses on key parameters such as slag viscosity at critical temperatures and contamination risk thresholds, rather than attempting to model every compositional detail. By identifying and monitoring the most influential parameters, the method simplifies the complexity of varying fuel compositions while maintaining accurate prediction capability for contamination risk.

Inventive Principle:
Principle #35Parameter changes

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

Enables the operation of power plants with a high percentage of biogenic fuels without excessive contamination, extending maintenance intervals and reducing the risk of slagging and corrosion, even in plants originally designed for coal.

Implementation Method 1

a model slag composition for different temperatures is determined using a thermodynamic model based on the total ash composition

Methodology Applied
Scientific EffectThermodynamic equilibrium:

Implementation Method 2

determining a viscosity of the model slag composition

Methodology Applied
Scientific EffectViscosity measurement:

Data Source

PatentEP3961099B1Method of operating a power plant with at least partial substitute fuel
Publication Date: 2022.11.09 RWE GENERATION NL BV
  • EP3961099B1 patent drawingFigure 1~2
  • EP3961099B1 patent drawingFigure 3~4
  • EP3961099B1 patent drawingFigure 5

AI summary

The present method for operating a power plant 31 makes it possible to investigate a model composition 2, 23, 24, 25, 26 with at least one biogenic substitute fuel with regard to the existing pollution risk 14 before the model composition 2, 23, 24, 25, 26 can be supplied as fuel 1 to the combustion chamber 32 of the power plant 31. In this way, the pollution of the combustion chamber 32 can be prevented and a power plant 31, which is fundamentally designed for the combustion of, for example, hard coal, can still be operated with a high proportion of biogenic fuels of 80 wt.% or more.