Steam Explosion Process for Polluted Wood Waste Pelletization

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Solution Overview

Problem

The existing Steam Explosion process is inefficient in treating polluted wood waste, as it does not effectively remove exogenous pollutants, leading to regulatory challenges and additional technical constraints for combustion installations, and results in significant energy consumption and material loss.

Innovation Solution

A modified Steam Explosion process involving steam injection at 200-300°C and 10-30 bar pressure, followed by explosive decompression, with optimized treatment durations based on pollutant type, to convert wood waste into fuel pellets or briquettes that can be used as a coal substitute, while minimizing energy consumption and material loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the traditional Steam Explosion process is used to treat polluted wood waste, then the processing can be performed with simple equipment, but the process fails to effectively remove exogenous pollutants

Engineering Contradiction:
Improveprocess simplicityVSAvoidpollutant removal efficiency
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the traditional Steam Explosion process by changing key parameters: increasing steam temperature to 200-300°C, raising pressure to 10-30 bar, and optimizing treatment duration based on pollutant type. These parameter changes enable effective pollutant removal while maintaining process feasibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary classification of wood waste by pollutant type before treatment. By identifying the nature and proportion of pollutants in advance, the process can be optimized with appropriate treatment durations, improving removal efficiency without unnecessary complexity

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the Steam Explosion process is applied to polluted wood, then the wood can be processed, but significant energy consumption occurs

Engineering Contradiction:
Improveprocessing capabilityVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

By optimizing steam temperature (200-300°C) and pressure (10-30 bar) parameters, the process achieves effective pollutant removal at moderate energy levels. The parameter optimization prevents excessive energy consumption while maintaining processing effectiveness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies treatment durations that are optimized but not excessive. By determining appropriate treatment times based on pollutant type (e.g., 10-30 minutes for chlorine-based pollutants), the process avoids unnecessary energy consumption from prolonged treatment

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If the Steam Explosion process is applied to polluted wood, then the wood can be converted to fuel, but material loss increases

Engineering Contradiction:
Improvefuel productionVSAvoidmaterial loss
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The optimized temperature and pressure parameters preserve more of the wood material's structural integrity while still removing pollutants. This reduces material degradation and loss during the treatment process

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

By applying treatment for optimized durations rather than excessive times, the process removes pollutants effectively while minimizing unnecessary degradation of the wood material, thereby reducing material loss

Inventive Principle:
Principle #16Partial or excessive action

4Reliability

If polluted wood is classified as waste for incineration, then regulatory compliance is achieved, but additional pollution control measures and technical constraints are required

Engineering Contradiction:
Improveregulatory complianceVSAvoidpollution control measures
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The process extracts and removes exogenous pollutants from the wood before fuel production. By taking out the harmful substances through optimized steam treatment, the resulting fuel meets combustion standards without requiring additional pollution control infrastructure

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The process converts the harmful polluted wood waste into a beneficial clean fuel product. By using the steam explosion treatment to remove pollutants, what was previously a harmful waste stream becomes a useful fuel source that complies with regulations without requiring separate treatment systems

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 process effectively removes pollutants from wood waste, producing biomass-compatible fuel pellets with a higher calorific value than natural wood, compatible with existing coal-fired installations, reducing the need for complex depollution treatments and minimizing energy consumption.

Implementation Method 1

Fragments of this wood are subjected to a first treatment in a chamber, by injection of steam between 200 and 300 °C and pressure increased to 10 to 30 bar

Methodology Applied
Scientific EffectSteam injection: Steam Explosion

Implementation Method 2

explosive decompression involves producing a sudden drop in pressure that causes some of the condensation water present in the material to re-evaporate. This sudden expansion of water vapor induces shear forces that are applied throughout the material, resulting in the mechanical rupture of its structure

Methodology Applied
Scientific EffectExplosive decompression: Steam Explosion

Data Source

PatentEP3913038B1Method for manufacturing pellets or fuel briquettes from waste wood
Publication Date: 2023.06.07 ELECTRICITE DE FRANCE
  • EP3913038B1 patent drawingFigure 1~2
  • EP3913038B1 patent drawingFigure 3
  • EP3913038B1 patent drawing

AI summary

The present invention relates to a process for manufacturing fuel pellets or briquettes from wood, according to which: - fragments of this wood are subjected to a first treatment in an enclosure, by injection of steam between 200 and 300 °C and pressure increase up to 10 to 30 bar, - then to a second explosive decompression treatment by sudden drop of said pressure so as to cause the bursting of said fragments; - said fragments are recovered and transformed into pellets or briquettes, after a preliminary drying step, characterized in that said wood fragments are wood fragments containing at least one exogenous pollutant, that the nature and proportion of said at least one pollutant are determined before the implementation of said first treatment and that the duration of this first treatment is adapted according to the nature of the major pollutant.