Experimental and numerical studies on the NO reaction pathways of NH3 cofiring with coal volatile matter
Year: 2025
Type: article
Abstract: Ammonia (NH 3 ) cofiring provides a promising solution to carbon reduction of coal-fired boilers, but it may lead to increased NO x emissions. However, many experiments observed that the NO x emissions exhibited an increase-then-decrease trend with the increase of NH 3 cofiring ratio ( R NH3 ), indicating that NO x could be controlled under high R NH3 . To reveal the underlying mechanism, the experiments of NH 3 cofiring with coal volatile were first conducted in a one-dimensional flow reactor to reveal that this trend is primarily attributed to the gaseous reactions of volatile and NH 3 . A chemical reactor network model was then constructed to investigate the influences of R NH3 on the NO reaction pathways of NH 3 . The predicted results replicated the increase and then decrease trend of NO x emissions as R NH3 increased beyond 25 %. It was found that NO formation is primarily controlled by the reactions between HNO/N and OH/H radicals. Under lower R NH3 , the concentrations of HNO/N increase with the increase of R NH3 leading to increased NO formation. Under higher R NH3 , however, much of the OH/H radicals are consumed by the dehydrogenation reactions of NH 3 which consequently inhibits the NO formation reactions. Therefore, the root mechanism of the increase-then-decrease trend of NO x emissions is attributed to the competition for the OH/H radicals between the initial and final steps of the NO formation reaction pathway.
Source: Fuel Processing Technology
Authors: Jingyang Han, Yan Xie, Jun Li, Xin Liu, Wenzhen Zhang, Heyang Wang
Institution: Tianjin University
Language: English
Subfield: Fluid Flow and Transfer Processes
Field: Chemical Engineering
Domain: Physical Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $3,180
OpenAlex ID: W4409191742