An experimental investigation of ammonia/landfill/air mixtures' pollutant emissions and temperature distribution under non-preheated moderate or intense low-oxygen dilution combustion

Environ Sci Pollut Res Int. 2023 Mar;30(13):38333-38348. doi: 10.1007/s11356-022-24986-3. Epub 2022 Dec 29.

Abstract

This paper investigates the non-preheated MILD combustion behavior of landfill/ammonia mixtures. The experiments were carried out in a laboratory-scale furnace. The effects of equivalence ratio variation, CO2 dilution, and ammonia on the furnace temperature distribution and exhaust gas emissions were analyzed attentively. The experiment results indicate that a non-preheated MILD combustion establishment can provide a uniform temperature distribution and lower pollutant emissions while maintaining the same thermal efficiency. According to the results, equivalence ratio changes affect the MILD temperature structure sensibly. Variation of equivalence ratio is also effective on the pollutant emissions. Moreover, the rich burn condition increases the CO emissions by bringing the HCN and H radicals into the related reactions. Whereas in lean-burn states, little amounts of CO are generated, while the NO concentrations are higher due to the NH2 pathways. The results also indicate that CO2 dilution reduces the furnace's peak temperature. However, CO2 dilution may also increase the O and OH radicals, allowing HCN molecules to react and generate NO. Regarding the ammonia addition experiments, it was figured out that ammonia increases NOx emissions, while decreasing CO2 concentrations affect the flame temperature profile.

Keywords: Ammonia/Landfill combustion; CO2 addition; MILD combustion furnace; NO formation mechanism.

MeSH terms

  • Air Pollutants* / analysis
  • Ammonia
  • Carbon Dioxide
  • Oxygen
  • Temperature

Substances

  • Air Pollutants
  • Ammonia
  • Oxygen
  • Carbon Dioxide