Gliding Arc NOx Formation for Low-Temperature Ammonia Synthesis
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Solution Overview
Problem
Existing nitrogen fixation technologies, such as the Haber-Bosch process, are energy-intensive and have a significant CO2 footprint, while plasma-based nitrogen fixation methods face a trade-off between energy consumption and ammonia yield, and require hydrogen, which is costly and contributes to CO2 emissions.
Innovation Solution
A plasma-assisted method using a gliding arc discharge device to convert nitrogen and oxygen from air into NOx, with adjustable NO2/NO ratios, followed by electrochemical reduction to produce ammonia at low temperatures and ambient pressure without the need for hydrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the Haber-Bosch process is used for nitrogen fixation, then ammonia production scale is large, but energy consumption is high and CO2 emissions are significant
Solution Approach 1:
The invention changes the operating parameters from high temperature (400-600°C) and high pressure (200-400 atm) in the Haber-Bosch process to ambient temperature and pressure conditions using plasma technology. This parameter change enables ammonia production without the extreme conditions that cause high energy consumption and CO2 emissions, while maintaining productivity through continuous plasma discharge.
Solution Approach 2:
The invention replaces the thermal-mechanical system of the Haber-Bosch process with a plasma-based system. Instead of using high temperature and pressure to drive the nitrogen-hydrogen reaction, the invention uses plasma discharge to activate nitrogen molecules, enabling the reaction to proceed under ambient conditions and significantly reducing energy consumption.
2Temperature
If plasma technology is used for nitrogen fixation, then operating conditions are moderate and reactor size is reduced, but ammonia yield is low
Solution Approach 1:
The invention applies preliminary action by using plasma discharge to pre-activate nitrogen molecules before they undergo the ammonia synthesis reaction. The plasma treatment creates reactive nitrogen species that are more prone to reaction, thereby enhancing the subsequent ammonia formation process and improving overall yield without requiring high temperature or pressure conditions.
Solution Approach 2:
The invention employs composite catalyst systems that combine multiple materials with complementary functions. The catalyst composition includes transition metals (such as iron, cobalt, or nickel) supported on porous materials, creating a composite structure that enhances both the activation of nitrogen by plasma and the subsequent hydrogenation to ammonia, thereby improving yield at moderate conditions.
3Productivity
If hydrogen is used in plasma-based nitrogen fixation, then ammonia synthesis is achieved, but cost increases and CO2 footprint remains
Solution Approach 1:
The invention extracts and eliminates the hydrogen component from the traditional nitrogen fixation process. Instead of using hydrogen gas (which typically comes from fossil fuel-based steam methane reforming with high CO2 emissions), the invention uses water as the hydrogen source. The plasma process splits water to provide hydrogen atoms for ammonia synthesis, thereby removing the CO2-intensive hydrogen production step while maintaining ammonia productivity.
Solution Approach 2:
The invention changes the hydrogen source parameter from molecular hydrogen (H2) to water (H2O). This parameter change fundamentally alters the process carbon footprint, as water splitting via plasma or electrochemical methods produces hydrogen in situ without the CO2 emissions associated with conventional hydrogen production from natural gas reforming.
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
This method achieves low-energy, low-temperature ammonia production directly from air, reducing energy consumption and CO2 emissions, and allows integration with renewable energy sources for flexible operation.
Implementation Method 1
plasma-assisted method using a gliding arc discharge device to convert nitrogen and oxygen from air into NOx
Implementation Method 2
energetic electrons generated by NTP can activate inert N2 molecules by electron impact excitation and dissociation to convert N2 into nitrogen compounds
Implementation Method 3
electrochemical reduction to produce ammonia at low temperatures and ambient pressure
Data Source
AI summary
According to a first aspect of the present invention, there is provided an apparatus for forming NOx from nitrogen and oxygen, the apparatus comprising: a gliding arc discharge, GAD, device arranged to generate a plasma; a passageway including an inlet for a feed gas comprising nitrogen and oxygen and an outlet for the NOx, wherein the passageway extends, at least in part, through the GAD device wherein, in use, the nitrogen and oxygen are reacted in the generated plasma, thereby forming the NOx from at least some of the nitrogen and oxygen; and a post-discharge container for adjusting the NO2/NO ratio in the formed NOx to from 1:2 to 2:1.