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Vol. 5 No. 1 (2026): February 2026 Issue

Ammonia as a hydrogen carrier: LES of ammonia-solid fuel firing at varying air staging ratios

Mohammad Nurizat Rahman
Energy Markets and Strategy, Energy Systems, DNV, 118227 Singapore
Muhamad Shazarizul Haziq Mohd Samsuri
Generation Unit, Generation and Environment, TNB Research, Kajang, Selangor, 43000, Malaysia
Suzana Yusup
Faculty of Engineering and Technology, Sunway University, Selangor, 47500, Malaysia
Ismail Shariff
Generation Unit, Generation and Environment, TNB Research, Kajang, Selangor, 43000, Malaysia

Corresponding Author(s) : Mohammad Nurizat Rahman

mohammadnurizatrahman@gmail.com

Future Energy, Vol. 5 No. 1 (2026): February 2026 Issue

Abstract

Hydrogen carriers, such as Ammonia (NH3), is anticipated to be used as a carbon-free alternative for solid fuels, such as coal. Hence, the effect of air staging ratio (ASR) on emissions from NH3 co-firing with sub-bituminous coal was numerically investigated in a small-scale coal combustor via a Large Eddy Simulation (LES) method. The validation with experimental data demonstrated a difference in nitrogen oxides (NOx) and temperature profiles of less than 10 %. Carbon dioxide (CO2) and sulphur dioxide (SO2) levels are decreasing as the NH3 percentage rises, but ASR has minimal influence. Increasing the ASR from 20 to 60 % resulted in NOx reduction, except for 60 calorific (cal.) % NH3, where NOx began to grow at ASR 60 %. In the said case, peak temperature was recorded in the over-fire Air (OFA) zone due to considerable unburned carbon (UC) oxidation, resulting in an increase in thermal NOx. Due to oxygen deficiency, coal volatiles and NH3 are thought to burn in the firing zone due to dominant devolatilization, resulting in significant UC/char oxidation in the OFA zone. Overall, with proper ASR tuning, NH3 co-firing can produce low CO2, SO2, and NOx, and existing coal-fired utility ASR technology can be used.

Keywords

Large Eddy Simulation (LES) Solid fuel Coal Ammonia Power Generation Air-staging combustion
Rahman, Mohammad Nurizat, Muhamad Shazarizul Haziq Mohd Samsuri, Suzana Yusup, and Ismail Shariff. 2025. “Ammonia As a Hydrogen Carrier: LES of Ammonia-Solid Fuel Firing at Varying Air Staging Ratios”. Future Energy 5 (1):41-52. https://fupubco.com/fuen/article/view/722.
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