Plasma Nozzle for SCR Urea Decomposition
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Solution Overview
Problem
Conventional SCR systems face challenges in quickly decomposing urea solutions into ammonia and mixing them with exhaust gases within limited spatial and thermal constraints, leading to inefficiencies in nitrogen oxide reduction and increased energy consumption.
Innovation Solution
A plasma nozzle is designed to atomize and pyrolyze liquids, such as urea solutions, using a plasma arc to rapidly mix them with gases, reducing the length and thermal mass required for effective ammonia generation and mixing with exhaust gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional spray methods are used to decompose urea solution into ammonia, then the decomposition process requires long pipe length and high temperature, but this increases thermal mass and energy consumption
Solution Approach 1:
The patent replaces conventional thermal decomposition methods with plasma technology. The plasma generator creates plasma that directly decomposes urea solution into ammonia through non-thermal plasma processes, eliminating the need for long heated pipes and high thermal mass, thus significantly reducing energy consumption while maintaining high decomposition speed
Solution Approach 2:
The invention changes the decomposition parameters by using plasma temperature and energy instead of conventional high thermal temperature. The plasma state allows decomposition to occur at lower thermal conditions but with high energy density, transforming the urea solution efficiently without requiring extensive thermal mass
2Stability of the object's composition
If conventional spray methods are used to mix ammonia with exhaust gas, then adequate mixing requires long pipe length, but this increases system size and thermal mass
Solution Approach 1:
The patent replaces conventional diffusion-based mixing in long pipes with plasma-enhanced mixing. The plasma generator creates turbulent flow and enhances mass transfer through plasma-induced effects, achieving uniform ammonia-exhaust gas mixing in a compact configuration with significantly reduced pipe length
Solution Approach 2:
The invention performs preliminary decomposition of urea solution into ammonia within the plasma generator before the mixing section. This pre-processing ensures that ammonia is already generated and available for immediate mixing with exhaust gas, eliminating the need for long mixing pipes and reducing overall system length
3Stability of the object's composition
If conventional burners are used for vaporizing and mixing liquid fuel, then stable evaporation performance is difficult to maintain under varying composition conditions
Solution Approach 1:
The patent replaces conventional thermal burners with plasma generators. Plasma provides consistent energy delivery through electromagnetic fields that ionize and decompose the liquid fuel regardless of composition variations. This plasma-based approach maintains stable evaporation and decomposition performance while adapting to different fuel compositions without requiring complex control 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
The plasma nozzle system enables rapid and efficient atomization and pyrolysis of urea solutions, effectively mixing ammonia with exhaust gases, reducing the size and temperature requirements of SCR systems, improving energy efficiency and nitrogen oxide reduction performance.
Implementation Method 1
atomizing and pyrolyzing a liquid supplied by generating plasma therein to be mixed and sprayed with a gas at a fast speed by heat due to a plasma arc
Implementation Method 2
atomizing and pyrolyzing a liquid supplied by generating plasma therein to be mixed and sprayed with a gas at a fast speed by heat due to a plasma arc and flow excited chemical species
Data Source
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AI summary
The present invention provides a plasma nozzle atomizing and pyrolyzing a liquid supplied by generating plasma therein to be mixed and sprayed with a gas with a fast speed by heat due to a plasma arc and flow excited chemical species. The plasma nozzle according to an exemplary embodiment of the present invention includes: a first housing discharging a supplied gas to a narrowed discharging port and being electrically grounded; a second housing provided near the discharging port of the first housing and spraying a liquid supplied through a spraying hole in the discharging port; and a driving electrode built in the first housing, forming a discharge gap along with the discharging port at an end part, and applied with a driving voltage.