Cofiring of hydrogen and pulverized coal in rotary kilns using one integrated burner

The grate-kiln process for iron-ore pellet induration utilizes pulverized coal fired burners. In a developed infrastructure for H2, it might be desirable to heat the existing rotary kilns with renewably produced H2. Technical challenges of H2 heating of grate-kilns include high emissions of NOX and...

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Bibliographic Details
Published in:International Journal of Hydrogen Energy
Main Authors: Johansson, Andreas, Fernberg, Johannes, Sepman, Alexey, Colin, Samuel, Wennebro, Jonas, Normann, Fredrik, Wiinikka, Henrik
Format: Article in Journal/Newspaper
Language:English
Published: RISE Research Institutes of Sweden, Bioraffinaderi och energi 2024
Subjects:
Coal
Coal combustion
Coal fueled furnaces
Iron ore pellets
Pulverized fuel
Co-firing
Combustion behaviours
Emission
Hydrogen combustion
Pellet induration
Process heat
Process temperature
Pulverized coal fired burner
Pulverized coals
Technical challenges
Rotary kilns
Energy Engineering
Energiteknik
Luossavaara
Piteå
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:ri:diva-76031
https://doi.org/10.1016/j.ijhydene.2024.09.327
Description
Summary:The grate-kiln process for iron-ore pellet induration utilizes pulverized coal fired burners. In a developed infrastructure for H2, it might be desirable to heat the existing rotary kilns with renewably produced H2. Technical challenges of H2 heating of grate-kilns include high emissions of NOX and maintaining sufficient heat transfer to the pellet bed. This article examined cofiring (70% coal/30% H2) in 130 kW experiments using two different integrated burner concepts. Compared to pure coal combustion, cofiring creates a more intense, smaller flame with earlier ignition and less fluctuations. The process temperature and heat transfer are enhanced in the beginning of the kiln. The co-fired flames emit 32% and 78% less NOX emissions compared to pure coal and H2 combustion, respectively. We can affect the combustion behavior and NOX emissions by the burner design. H2/coal cofiring using integrated burners is probably an attractive solution for emission minimization in rotary kilns. The authors gratefully acknowledge Luossavaara-Kiirunavaara AB (LKAB), the Swedish Energy Agency and the European Union (EU) for the financial support of this work (P2022-00196). Additionally, all experimental support provided from our colleagues Niklas Mörtlund, Therese Vikström, Sandra Lundström and others at RISE, Piteå is greatly appreciated.

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