Ozone Injection for NOx Removal in Sulfuric Acid Plants
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Solution Overview
Problem
Current methods for removing nitrogen oxides (NOx) in sulfuric acid production processes are inadequate, leading to environmental emissions and product quality issues, particularly with oxygen enrichment increasing NOx formation and niter content, which hampers the economic viability of smaller sulfuric acid production plants.
Innovation Solution
Injecting ozone into the gas stream in a sulfuric acid production process to oxidize insoluble NOx to highly soluble oxides of nitrogen, such as N2O5, which can then be easily scrubbed with water, either downstream of the sulfur dioxide generation furnace or after the candle mist eliminator, using a particulate scrubber and environmental scrubber respectively, to reduce NOx emissions and niter content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxygen enrichment is used to increase sulfuric acid production capacity, then productivity increases, but nitrogen oxides formation increases
Solution Approach 1:
The patent applies ozone injection as a strong oxidant to convert nitrogen oxides (NO and NO2) into higher oxides (N2O5, HNO3) that are more soluble and can be easily removed by existing scrubbing systems. This allows the plant to maintain high oxygen enrichment levels for increased productivity while controlling harmful NOx emissions through chemical transformation rather than reduction.
2Object-generated harmful factors
If conventional NOx removal methods are used, then nitrogen oxides emissions are reduced, but product quality deteriorates due to niter formation
Solution Approach 1:
The patent applies preliminary oxidation of nitrogen oxides to higher oxides (N2O5, HNO3) using ozone before the gas stream enters the sulfuric acid absorption section. This preliminary action transforms NOx into forms that are readily soluble in water and can be removed by scrubbers, preventing them from reaching the product acid and forming niter, thus protecting product quality while achieving NOx emission control.
3Object-generated harmful factors
If dual stage absorption and caustic scrubbing are used, then nitrogen oxides emissions are reduced, but device complexity increases
Solution Approach 1:
The patent extracts the nitrogen oxide removal function from the complex dual-stage absorption and caustic scrubbing system by injecting ozone to chemically transform NOx into highly soluble oxides (N2O5, HNO3) that can be removed by simple water scrubbing. This extraction approach eliminates the need for complex multi-stage equipment while achieving effective NOx control through a single, simplified scrubbing step.
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
Effectively reduces NOx emissions and niter content in the sulfuric acid product, enhancing the operational efficiency and environmental compliance of sulfuric acid production plants, while allowing for increased capacity and reduced costs through ozone-based NOx removal, without the need for significant capital investment or energy-intensive processes.
Implementation Method 1
contacting said waste gas stream with ozone to oxidize insoluble NOx to highly soluble oxides of nitrogen
Data Source
AI summary
The present invention provides for process for inhibiting the levels of nitrogen oxides in process gas streams from sulfuric acid regeneration and production plants. The process gas stream from the waste heat boiler and the candle mist eliminator is contacted with ozone which will react with nitrogen oxides present in the flue gas.