Scaling of Pulverized-Fuel Jet Flames That Apply Large Amounts of Excess Air - Implications for NOx Formation
Journal article, 2019

Measures to reduce nitrogen oxides (NOx) formation in industrial combustion processes often require up-scaling through pilot-scale facilities prior to being implemented in commercial scale, and scaling is therefore an important aspect of achieving lower NOx emissions. The current paper is a combined experimental and modelling study that aims to expand the understanding of constant velocity scaling for industrial jet flames applying high amounts of excess air. These types of flames are found in e.g., rotary kilns for production of iron ore pellets. The results show that, even if the combustion settings, velocity, and temperature profiles are correctly scaled, the concentration of oxygen experienced by the fuel during char combustion will scale differently. As the NO formation from the char combustion is important in these flames, the differences induced by the scaling has important impacts on the efficiencies of the applied primary measures. Increasing the rate of char combustion (to increase the Damköhler number), by using, for  example, smaller-sized particles, in the pilot-scale is recommended to improve scaling.


rotary kiln






Rikard Edland

Chalmers, Space, Earth and Environment, Energy Technology

Fredrik Normann

Chalmers, Space, Earth and Environment, Energy Technology

Thomas Allgurén

Chalmers, Space, Earth and Environment, Energy Technology

Christian Fredriksson


Klas Andersson

Chalmers, Space, Earth and Environment, Energy Technology


1996-1073 (ISSN)

Vol. 12 14 2680

Reduced CO2 emissions from LKABs rotary kiln process – a study of the effect of alternative fuels

LKAB (Roteringsugnsprocess), 2013-05-01 -- 2016-04-30.

Swedish Energy Agency (2012-009098), 2013-05-01 -- 2016-04-30.

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Inorganic Chemistry

Other Engineering and Technologies

Energy Engineering

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