Waste Combustion Using CO2-Rich Recirculated Oxygen Carrier Gas
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Solution Overview
Problem
Existing waste incineration plants face challenges in efficiently separating CO₂ from exhaust gases due to low CO₂ concentrations, which necessitate complex and costly flue gas cleaning systems, and oxygen enrichment processes are limited by high thermal loads and complex control systems.
Innovation Solution
A method involving the use of an oxygen-carrier gas mixture, comprising recirculated gas with a CO₂ concentration of 10 to 99%, is added to the combustion process, increasing the CO₂ concentration in exhaust gases and facilitating easier separation, while maintaining controllable combustion temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If oxygen enrichment of primary combustion air is used to reduce flue gas volume, then CO2 concentration in exhaust gas increases, but thermal load on system increases and control complexity increases
Solution Approach 1:
The patent divides the oxygen supply into two separate stages: primary combustion air (with lower oxygen enrichment, 25-40 vol.%) and secondary combustion air (with higher oxygen enrichment, 40-100 vol.%). This segmentation allows the primary combustion to occur at controlled temperatures while the secondary combustion receives highly enriched oxygen, achieving high CO2 concentration without excessive thermal load on the entire system.
Solution Approach 2:
Different regions of the combustion process receive different oxygen concentrations tailored to their specific needs. The primary combustion zone receives moderate oxygen enrichment (25-40 vol.%) to maintain stable combustion, while the secondary combustion zone receives high oxygen enrichment (40-100 vol.%) to maximize CO2 production. This local optimization resolves the contradiction between thermal load and CO2 concentration.
2Quantity of substance
If oxygen enrichment of primary combustion air is used to reduce flue gas volume, then CO2 concentration in exhaust gas increases, but control system complexity increases
Solution Approach 1:
The control system is segmented into two independent control loops: one for primary combustion air oxygen enrichment (25-40 vol.%) and another for secondary combustion air oxygen enrichment (40-100 vol.%). This segmentation simplifies control by allowing each zone to be optimized independently, reducing the overall control complexity while achieving high CO2 concentration in the exhaust gas.
3Power
If high oxygen concentration is supplied to combustion process, then combustion temperature increases, but thermal stress on components increases
Solution Approach 1:
The patent segments the oxygen supply strategy: primary combustion air receives moderate enrichment (25-40 vol.%) to maintain components within permissible thermal limits, while secondary combustion air receives high enrichment (40-100 vol.%) to achieve high combustion efficiency and CO2 concentration. This segmentation allows high power output without excessive thermal stress on components.
Solution Approach 2:
The patent changes the oxygen concentration parameter across different combustion stages: primary combustion operates at 25-40 vol.% oxygen to protect components from thermal stress, while secondary combustion operates at 40-100 vol.% oxygen to maximize combustion efficiency. This parameter optimization resolves the contradiction between power output and thermal stress.
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
Easier CO₂ separation and reduced flue gas volume are achieved, with improved controllability and reduced thermal stress on system components, enabling more efficient CO₂ capture and simplified control systems.
Implementation Method 1
oxygen is added to the combustion process as an oxygen-carrier gas mixture, wherein the carrier gas is recirculated gas from the combustion plant with a CO2 concentration of 10 to 99%
Implementation Method 2
oxygen is added to the combustion process as an oxygen-carrier gas mixture
Data Source
Figure 1~2
AI summary
The invention relates to a method for burning waste on a combustion grate of a combustion plant and a device for carrying out such a method, in which oxygen is added to the combustion with a carrier gas as an oxygen-carrier gas mixture, which is recirculated gas from the combustion plant with a CO2 concentration of 10 to 99%.