Waste Incinerator Bed Combustion Model for High Moisture Waste
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Solution Overview
Problem
Existing methods for calculating gas-solid two-phase combustion in waste incinerator beds suffer from inaccuracies due to limited consideration of waste component elements, neglect of water content, and simplistic boundary conditions, leading to poor calculation accuracy and incomplete simulations, especially for municipal solid waste with high moisture content.
Innovation Solution
A comprehensive model incorporating moisture evaporation, volatile matter analysis, and fixed carbon combustion, including equations for CO, H2, CH4, NH3, H2S, and their reactions with O2 and water vapor, along with detailed boundary conditions for heat and mass transfer, to accurately simulate the incineration process and account for N and S trace elements, improving calculation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Flic model is used for calculation, then the calculation is based on three conservation laws, but the calculation accuracy remains low and applications are narrow due to limited waste component elements considered
Solution Approach 1:
The patent expands the waste component elements from the traditional three elements (C, H, O) to include N and S trace elements, changing the compositional parameters of the model. This allows the simulation to account for NOX and SOX pollutant generation, thereby improving calculation accuracy and application scope while maintaining the conservation law basis.
2Reliability
If the Flic model is used, then governing equations are established according to conservation laws, but water vapor chemical reactions are not considered leading to inaccurate results for high moisture waste
Solution Approach 1:
The patent adds water vapor as a reactive chemical species in the governing equations, changing the chemical reaction parameters to include water-gas shift reactions and other vapor-phase reactions. This enables accurate simulation of high moisture waste incineration processes while maintaining the rigorous governing equations framework.
3Measurement precision
If the bed empirical model is used, then field distribution results can be obtained, but the results are semi-empirical with large errors as they are not strictly based on conservation laws
Solution Approach 1:
The patent segments the incineration process into distinct zones (drying zone, pyrolysis zone, combustion zone, cooling zone) and establishes separate governing equations for each zone while ensuring overall conservation of mass, energy, and momentum. This allows accurate field distribution results to be obtained while maintaining strict compliance with conservation laws throughout the system.
4Ease of manufacture
If simple boundary conditions are assumed in the Flic model, then calculation is simplified, but large deviations occur under severe external heat and mass transfer conditions
Solution Approach 1:
The patent implements dynamic boundary conditions that adapt to severe external heat and mass transfer conditions, allowing the model to automatically adjust heat transfer coefficients, mass transfer rates, and boundary fluxes based on local conditions. This maintains model simplicity while achieving high accuracy under varying operational conditions including severe heat and mass transfer scenarios.
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 proposed method enhances calculation accuracy by simulating the generation of NOX and SOX pollutants and accurately representing incineration conditions, particularly for municipal solid waste with high water content, leading to more reliable simulation results.
Implementation Method 1
a moisture evaporation model
Implementation Method 2
a volatile matter combustion model... includes a combustion reaction equation for said volatile matter and O2, and respective equations for CO and CH4 reacting with water vapor
Implementation Method 3
the reaction between combustible components and water vapor is still neglected
Data Source
AI summary
Disclosed is a method for calculating combustion in the bed of a waste incinerator. The method is based on a model of combustion in a waste incinerator bed and comprises a water evaporation model, a volatile matter analysis model, a volatile matter combustion model, and a fixed carbon combustion model. The volatile matter of the volatile matter combustion model comprises CO, H2, CH4, NH3, and H2S. The volatile matter combustion model comprises a combustion reaction equation for said volatile matter and O2, and respective equations for CO and CH4 reacting with water vapor. Equations governing the model of combustion in the bed of a waste incinerator comprise a continuity equation, an energy equation, a momentum equation, and a component equation. Boundary conditions of said governing equations comprise: equations of heat transfer and mass transfer from an upper boundary layer of the bed to the exterior; and equations of heat transfer and mass transfer from lower boundary layer of the bed to the exterior.