Solid Fired Hot Gas Generator Drying Wood Chips

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Solution Overview

Problem

Existing methods for drying wood fibers and chips in drum dryers rely on fossil fuels and have high energy consumption, with heat-exchangers facing thermal strain and reduced lifespan due to high temperatures needed for pollutant burning-off, and inefficient use of thermal energy in exhaust gases.

Innovation Solution

An apparatus and method utilizing a solid fired hot gas generator in combination with a multi-fuel burner, featuring a heat-exchanger and hot gas cyclone for indirect heating of drying vapors, allowing for the combustion of organic materials and efficient thermal energy recycling, with a hot gas cyclone for effective solid particle removal and reduced wear on equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If high temperatures are used in the combustion chamber to burn off pollutants, then pollutant removal is improved, but the thermal strain on heat-exchanger elements increases and their lifetime is reduced

Engineering Contradiction:
Improvepollutant removalVSAvoidheat-exchanger lifetime
Core Design Contradiction:
Object-generated harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The combustion chamber is divided into two distinct zones: a first zone for burning off pollutants at high temperatures, and a second zone for heating the drying gases at lower temperatures. This segmentation allows the heat-exchanger to be positioned only in the second zone, exposing it to lower temperatures and reducing thermal strain while maintaining effective pollutant removal in the first zone.

Inventive Principle:
Principle #1Segmentation

2Productivity

If fossil fuels are used in traditional burners, then drying process is maintained, but energy consumption is high and thermal efficiency is reduced

Engineering Contradiction:
Improvedrying process continuityVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The system uses the waste heat from the combustion chamber exhaust gases to preheat the drying gases through the heat-exchanger. This self-service approach recovers thermal energy that would otherwise be wasted, reducing the additional energy required to maintain the drying process and improving overall thermal efficiency.

Inventive Principle:
Principle #25Self-service

3Quantity of substance

If drying vapors are continuously removed and recirculated through the heat-exchanger, then mass balance is achieved, but thermal energy in exhaust gases is not efficiently utilized

Engineering Contradiction:
Improvevapor mass balanceVSAvoidthermal energy loss
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

Instead of discarding the thermal energy in the combustion chamber exhaust gases, the system recovers this heat through the heat-exchanger to preheat the drying gases. This recovery process converts what would be wasted energy into a useful resource, reducing overall energy consumption while maintaining the necessary vapor recirculation for mass balance.

Inventive Principle:
Principle #34Discarding and recovering

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 reduces energy consumption, extends the lifespan of heat-exchanger components, enhances thermal and energetic efficiency, and allows for the recycling of materials that cannot be used in traditional systems, while minimizing emissions and wear on apparatus components.

Implementation Method 1

the drying vapors are indirectly heated via a heat-exchanger

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

hot gas cyclone for effective solid particle removal

Methodology Applied
Scientific EffectCyclone separation: Cyclone Separation

Implementation Method 3

solid fired hot gas generator... allowing for the combustion of organic materials

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3589891B1Apparatus and method for continuously drying bulk goods, in particular wood chips and/or wood fibers comprising a solid fired hot gas generator
Publication Date: 2024.11.20 KRONOPLUS LTD
  • EP3589891B1 patent drawingFigure 1
  • EP3589891B1 patent drawingFigure 2
  • EP3589891B1 patent drawingFigure 3

AI summary

The present invention relates to an apparatus and a method for continuously drying bulk goods, in particular wood fibers and/or wood chips, in a dryer, wherein the drying vapors are led to a dryer (1) circuit, in which the drying vapors are indirectly heated via a heat- exchanger (4) and are conducted to the dryer (1) again.