Ash Recycling System Hardness Control

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Solution Overview

Problem

Incineration plants face significant wear and tear on components due to the hardness of ash residues, which is not effectively managed by existing methods, leading to increased maintenance and operational costs.

Innovation Solution

A method that involves monitoring and adjusting the hardness of ash residues by removing and processing them with a specific control loop, using water treatment and additional fuel to reduce hardness, and recycling ash through the combustion boiler, thereby reducing wear on components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ash is removed and processed as is, then the combustion boiler can operate continuously, but the hardness of the ash causes significant wear on components such as shredders and conveyors

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidwear on components
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The ash is subjected to preliminary treatment processes including washing with water, drying, and crushing before being fed back into the combustion boiler. This preliminary action reduces the hardness and abrasive properties of the ash, thereby reducing wear on components while maintaining continuous operation capability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The physical and chemical parameters of the ash are changed through washing (adding water), drying (removing water), and crushing (mechanical breakdown). These parameter changes reduce the hardness and particle size of the ash, making it less damaging to equipment while allowing continuous boiler operation

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If ash is treated and re-fed into the combustion boiler, then component wear is reduced, but additional processing steps and equipment are required

Engineering Contradiction:
Improvewear on componentsVSAvoidprocessing system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system uses the ash itself as the material being processed and reused. The ash is washed, dried, and crushed, then fed back into the combustion boiler where it serves as fuel. This self-service approach reduces wear without requiring external intervention or complex additional processing systems

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Instead of discarding the ash after combustion, the system recovers it by washing, drying, and crushing, then re-feeds it into the combustion boiler. This recovery process reduces component wear while the additional equipment required is offset by the value of extended component lifespan and reduced maintenance needs

Inventive Principle:
Principle #34Discarding and recovering

3Object-affected harmful factors

If water is used to treat the ash, then the hardness and chunk size are reduced, but water handling equipment and environmental compliance requirements are added

Engineering Contradiction:
Improveash hardness and chunk sizeVSAvoidwater handling system
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Water is used to wash the ash, and the water-ash mixture is then dried using thermal energy from the combustion process. This hydraulic treatment effectively reduces ash hardness and chunk size, while the drying step eliminates the need for complex water removal equipment

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The ash undergoes phase transition from a wet state (after washing) to a dry state (after thermal drying). This phase transition allows the ash to be effectively processed and re-fed into the combustion boiler, reducing hardness while the thermal drying process integrates with existing boiler operations

Inventive Principle:
Principle #36Phase transitions

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 method significantly reduces wear on components by adjusting ash hardness, potentially by 15-20%, extending the lifespan of equipment like coal shredders and maintaining operational efficiency while adhering to environmental regulations.

Implementation Method 1

The water acting on the ash or on the ash leads, on the one hand, to a smaller chunk size of the ash to be removed and can also cause a certain 'softening' of the baked, sometimes sintered, ash slag (reduction in the hardness range)

Methodology Applied
Scientific EffectSoftening:

Implementation Method 2

The heat of the flue gases generated by combustion is absorbed and further used in such systems using heat exchangers

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

combustion boiler with an ash outlet to access (at least) a conveyor for removing and cooling the hot ash

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP2260242B1System for ash recycling
Publication Date: 2013.04.24 CLYDE BERGEMANN DRYCON GMBH
  • EP2260242B1 patent drawingFigure 1

AI summary

A method for operating a combustion system (1) comprising at least the following steps: a) removing ashes from a combustion boiler (2), b) compacting the ashes, c) pulverizing the ashes, and d) feeding at least a part of the ashes into the combustion boiler (2), wherein the hardness of said ashes is deliberately set during steps a) or b). Furthermore, a particularly suitable device for implementing the method is disclosed.