Multi-aperture Ammonia Supply Element for Exhaust Gas Mixing
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Solution Overview
Problem
Existing exhaust gas treatment systems face challenges in effectively mixing reductants with exhaust gases due to the length of the mixing part, which affects NOx reduction efficiency and system length, requiring a balance between sufficient mixing and minimizing system length.
Innovation Solution
A compact exhaust gas treatment arrangement using a supply element with multiple discharge apertures to disperse ammonia gas uniformly into the exhaust gases, eliminating the need for a lengthy mixing part and allowing direct mixing without phase change, thereby reducing system length and material usage while maintaining high temperature for improved catalytic reaction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mixing part is made longer to improve reductant mixing and conversion, then the NOx reduction effectiveness is improved, but the total system length increases
Solution Approach 1:
The supply element is divided into multiple discharge apertures arranged at different positions and orientations around the exhaust gas flow path. This segmentation allows the reductant to be injected at multiple locations simultaneously, achieving thorough mixing in a compact space without requiring a long mixing part, thus resolving the contradiction between mixing effectiveness and system length.
Solution Approach 2:
The discharge apertures are arranged in three-dimensional space around the exhaust pipe, with some facing upstream, downstream, and laterally. This spatial distribution in multiple dimensions enables comprehensive mixing of reductant with exhaust gases in a short distance, eliminating the need for extended mixing length while maintaining high NOx reduction effectiveness.
2Length of moving object
If the mixing part is made shorter to reduce system length, then the total system length is reduced, but the reductant mixing and conversion become insufficient
Solution Approach 1:
The reductant is pre-mixed with carrier gas (air or oxygen) before injection into the exhaust stream. This preliminary mixing ensures that the reductant is already in a dispersed state, enabling rapid and sufficient mixing with exhaust gases even in a short mixing part, thereby maintaining NOx reduction effectiveness while minimizing system length.
Solution Approach 2:
Carrier gas (air or oxygen) is introduced along with the reductant through the supply element to facilitate rapid mixing and conversion. The pneumatic assistance from the carrier gas ensures sufficient mixing and conversion of reductant in a short distance, resolving the contradiction between short system length and adequate mixing effectiveness.
3Quantity of substance
If urea is used as reductant requiring phase change from liquid to gas, then the reductant can be stored and transported, but the mixing process becomes more complex and time-consuming
Solution Approach 1:
Urea is pre-heated and converted to ammonia gas in a separate heating section before injection into the exhaust stream. This preliminary phase change separates the complex heating process from the mixing process, allowing simple injection through the supply element while maintaining reductant availability, thus reducing overall system complexity.
Solution Approach 2:
Carrier gas (air or oxygen) serves as an intermediary medium to transport the reductant from the supply element into the exhaust gas flow. This intermediary approach simplifies the injection mechanism by using gas-phase reductant mixed with carrier gas, avoiding the complexity of direct liquid injection and phase change within the mixing section.
4Reliability
If more material is used to create a longer mixing part, then the mixing effectiveness is improved, but the material cost increases
Solution Approach 1:
Instead of using a long continuous mixing part requiring extensive material, the supply element is segmented into multiple discharge apertures distributed around the exhaust pipe. This segmentation achieves effective mixing in a compact structure, significantly reducing the amount of material required while maintaining high mixing effectiveness.
Solution Approach 2:
The discharge apertures are strategically positioned at specific locations around the exhaust pipe where exhaust gas flow characteristics favor rapid mixing. This localized optimization of discharge positions maximizes mixing efficiency in a short distance, eliminating the need for long mixing parts and reducing material consumption.
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 solution achieves efficient NOx reduction with reduced system length, lower material costs, and minimized backpressure losses, ensuring effective mixing and increased temperature for enhanced catalytic converter performance.
Implementation Method 1
the ammonia gas is dispersible from the discharge apertures into the exhaust gases in the flow path
Implementation Method 2
exhaust gases flowing along a flow path in an exhaust pipe system
Implementation Method 3
Inside the catalytic converter the ammonia gas reacts with the exhaust gases in a chemical process resulting in a reduction of the level of NOx
Data Source
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AI summary
The invention relates to an exhaust gas treatment arrangement (1) and a method thereof for treating exhaust gases flowing along a flow path (2) in an exhaust pipe system (3). The arrangement (1) comprises a supply element (4) being in communication with a source (5) comprising an ammonia gas. The supply element (4) comprises at least two discharge apertures (6a, 6b, 6c) being adapted to communicate with the flow path (2) such that the ammonia gas may be dispersible from the discharge apertures (6a, 6b, 6c) into the exhaust gases in the flow path (2) in at least two discharge directions (7a, 7b, 7c).