Generation of nitrous oxide emissions from the production of nitric acid

  • Steve Howe
    1 year, 11 months ago #5267

    How does the production of nitric acid result in nitrous oxide being emitted into the atmosphere?

    1 year, 11 months ago #5268

    This is covered by IFS Proceedings 861, How green ammonia feed and state of the art nitrous oxide abatement contribute to green nitric acid production, by Daniel Birke and Bernd Mielke of thyssenkrupp Industrial Solutions.

    They write ‘The industrial production of nitric acid (HNO3) involves oxidising ammonia (NH3) with air over a platinum/rhodium gauze catalyst to produce nitrogen oxides. This process yields nitrogen monoxide (NO), which then reacts with oxygen and water to form nitric acid. However, it also produces nitrous oxide (N2O) – a greenhouse gas and ozone killer – as an undesired by-product. Unlike NO, the nitrous oxide is not involved in the HNO3 production process and would be emitted to the atmosphere if not appropriately treated.
    The N2O formation in nitric acid plants vary from about 3-4 kg of N2O per metric ton of HNO3 to as much as 20 kg of N2O per metric ton of HNO3 depending on the type of nitric acid plant. An estimated 400,000 metric tonnes of nitrous oxide are emitted annually (at the time of writing) by nitric acid plants worldwide. Due to its longevity in the earth’s atmosphere and its special absorption properties for infrared radiation, N2O is a potent greenhouse gas. One metric tonne of N2O emissions has the same effect on global warming as about 300 metric tonnes of CO2 (in future the European Emission Trading System may use a value of 265 as global warming potential (GWP). Consequently, nitric acid plants are now the largest single source of greenhouse gas emissions among industrial manufacturing facilities’

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