Combustion Residue Return Control for Sintering
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Solution Overview
Problem
Existing processes for managing combustion residue in waste incinerators fail to ensure complete sintering or melting, leading to increased unmelted residues, altered material composition, and decreased combustion bed temperature, which negatively impacts the combustion process.
Innovation Solution
A process that regulates the return of combustion residues within defined tolerance limits, adjusts combustion conditions, and modifies the material composition by adding selected fractions or additives like scrap metal to enhance melting and sintering, while monitoring essential combustion parameters to optimize residue return.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If combustion residue is returned to the combustion process, then the proportion of combustion residue in the fuel mixture increases, but the temperature of the combustion bed decreases
Solution Approach 1:
The patent applies parameter changes by adjusting the material composition of the returned combustion residue through selective fractionation. By separating fine slag fractions (rich in calcium oxide) from coarser fractions, the patent modifies the chemical composition parameters of the returned material to control its impact on combustion temperature while maintaining beneficial residue return effects.
Solution Approach 2:
The patent segments the combustion residue into different size fractions using classification equipment. Fine fractions (<2mm) are separated from coarser fractions and returned to the combustion process at controlled rates. This segmentation allows selective return of fractions with different thermal and compositional properties, enabling independent control of temperature and residue proportion effects.
2Quantity of substance
If fine slag fractions with high calcium oxide content are returned, then the average lime content of the combustion residue increases, but the melting temperature and sintering reactivity are adversely affected
Solution Approach 1:
The patent changes the material composition parameters by selectively returning specific fractions of combustion residue. By controlling which size fractions are returned and at what rates, the patent adjusts the overall chemical composition (particularly calcium oxide content) and physical properties (grain size distribution) to optimize both lime content and melting/sintering performance.
Solution Approach 2:
The patent applies local quality by returning different fractions to different locations in the combustion process or at different rates. Fine fractions may be returned to specific zones where their high lime content is beneficial, while coarser fractions are returned to zones where they provide better thermal stability and sintering characteristics.
3Productivity
If combustion residue is returned without regulation, then the temperature of the combustion bed continues to drop, but complete sintering and melting cannot be ensured
Solution Approach 1:
The patent implements feedback control by continuously monitoring combustion bed temperature and other combustion parameters, then using this information to adjust the rate and composition of returned combustion residue. This closed-loop control ensures that temperature remains within optimal ranges for complete sintering and melting while maintaining high combustion efficiency.
Solution Approach 2:
The patent applies dynamics by making the return rate and composition of combustion residue variable rather than constant. The system dynamically adjusts these parameters in response to changing combustion conditions, fuel composition, and residue accumulation rates, enabling continuous optimization of both efficiency and sintering completeness.
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
Ensures nearly complete sintering or melting of residues, allowing for increased return quantities and improved combustion conditions, maintaining stable combustion parameters and reducing the basicity of the combustion residue.
Implementation Method 1
the fuel is burned on a furnace grate... the temperature of the combustion bed... the melting and sintering processes in the combustion bed
Implementation Method 2
a portion of the combustion residue melts and/or sinters in the combustion bed... essentially all of the solid combustion residue in the combustion bed is sintered and/or melted
Data Source
AI summary
Combustion residue can be partially melted and/or sintered in the combustion bed of a grate furnace system. By returning the unmelted and/or unsintered combustion residue, completely sintered inert granulates are obtained. To control the melting and/or sintering processes, at least one of the following process steps is implemented: the residues are returned only as long as, and only in such an amount that the changes thus caused in the essential combustion parameters remain within previously defined tolerance limits; the combustion conditions of the combustion process are changed in such a way as to counteract the changes in the combustion parameters produced by the return; the material composition of the combustion residue is changed by the return of selected fractions of the combustion residue so that the melting and/or sintering process of the combustion residue is influenced; and the material composition of the combustion residue is changed by the addition of additives is that the melting and/or sintering process of the combustion residue is influenced.