Metal Powder Burner Recirculation for Stable Low-Emission Combustion
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Solution Overview
Problem
Current combustion processes for metal powders, particularly iron powder, result in uncontrolled ignition leading to excessive evaporation, loss of mass, and high emissions of pollutants like carbon dioxide and nitrogen oxides, making them unsuitable for sustainable energy storage and recycling.
Innovation Solution
A burner design with a re-circulation channel for exhaust gases that mixes metal powder with partly cooled exhaust gases before introducing fresh air, maintaining a sub-stoichiometric oxygen environment for partial combustion, followed by controlled introduction of fresh air to achieve complete combustion, while using a heat exchanger to manage temperature and oxygen levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If normal air at lean conditions is used for metal powder combustion, then ignition speed is improved, but excessive evaporation and mass loss occur leading to high pollutant emissions
Solution Approach 1:
The combustion process is divided into multiple stages with different air supply conditions. The first stage uses lean air conditions for rapid ignition, while the second stage introduces excess air for complete combustion. This segmentation allows the system to achieve both fast ignition and low emissions by controlling oxygen availability at different combustion phases.
Solution Approach 2:
The air supply is controlled periodically with two distinct phases: an initial phase with limited air supply to enable fast ignition, followed by a second phase with excess air supply to ensure complete combustion. This periodic control of oxygen availability resolves the contradiction between ignition speed and emission reduction.
2Productivity
If excess air is supplied for complete combustion, then combustion efficiency is improved, but combustion temperature increases leading to excessive evaporation and mass loss
Solution Approach 1:
The combustion process is segmented into two stages: first stage with controlled air supply for partial combustion at lower temperatures, and second stage with excess air for complete combustion. This segmentation allows efficient combustion while controlling temperature to minimize evaporation and mass loss.
Solution Approach 2:
The first stage of combustion with controlled air supply prepares the system by initiating combustion at lower temperatures, preventing excessive evaporation. The second stage then completes the combustion efficiently. This preliminary controlled combustion action prevents mass loss before the high-efficiency combustion phase.
3Power
If fast combustion is achieved with lean air conditions, then energy release rate is improved, but particle temperature overshoots leading to excessive evaporation and smoke formation
Solution Approach 1:
The energy release process is divided into two phases: the first phase with lean air conditions provides rapid energy release, while the second phase with excess air ensures complete combustion at controlled temperatures. This segmentation prevents temperature overshoot and excessive evaporation while maintaining high power output.
Solution Approach 2:
Air supply is applied periodically in two phases: initial lean conditions for high power energy release, followed by excess air supply to control particle temperature and prevent evaporation. This periodic control resolves the contradiction between power output and temperature control.
4Device complexity
If uncontrolled ignition is used for metal powder combustion, then process simplicity is improved, but combustion stability deteriorates leading to high emissions and material loss
Solution Approach 1:
The air supply system dynamically adjusts oxygen availability in two stages: first stage with limited air for controlled ignition, and second stage with excess air for stable complete combustion. This dynamic control ensures combustion stability and reliability while maintaining practical system complexity.
Solution Approach 2:
The combustion process uses periodic air supply control with distinct phases for ignition and complete combustion. This periodic action provides stable and reliable combustion while avoiding the complexity of continuous adjustment systems.
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
Stabilizes the combustion process, reduces evaporation and emissions, allowing for efficient conversion of metal powders to metal oxides with minimal loss and low pollutant formation, suitable for sustainable energy storage and recycling.
Implementation Method 1
mixes metal powder with partly cooled exhaust gases before introducing fresh air
Implementation Method 2
combustion of metal powder, particularly iron powder
Implementation Method 3
the metal is being combusted to form metal oxide
Data Source
Figure 1~2
AI summary
A burner (1) for combusting metal powder, particularly iron powder, comprising a combustion chamber (2) containing a combustion space for holding a combustion flame during operation, the combustion chamber having an air inlet (3), a metal powder inlet (4), and a exhaust gas outlet (5), characterized in that the combustion chamber (2) has a recirculation channel (7) for recirculating exhaust gases, the recirculation channel (7) being in communication with the combustion space within said combustion chamber (2), and the recirculation channel (7) intersecting with the air inlet (3).