TITLE:
Numerical Study on NOx Emissions of Methane Re-Combustion in a 600 MWe Coal-Fired Boiler
AUTHORS:
Xiaotao Zhang, Hussain Ahmad Madni Gondal, Foyuan Duan, Weidong Zhang, Haoliang Mu, Chengyu Zhang, Aijun Wang
KEYWORDS:
Numerical Simulation, Re-Combustion, NOx Emission Reduction
JOURNAL NAME:
Energy and Power Engineering,
Vol.12 No.3,
March
27,
2020
ABSTRACT: The fuel staging combustion technology is a promising low NOx combustion technology for coal-fired boiler. In order to reduce NOx emissions, the burners of a 600 MWe coal-fired boiler are retrofitted in which methane gas is selected as a secondary fuel for re-combustion. The CFD models of combustion process are built to investigate effects of the methane gasratio on combustion process and NOx emissions. A total of 4 cases are numerically studied, including the pure coal combustion case, the coal combustion with 7.5%, 10%, 12.5% of methane gas re-combustion cases respectively. The results show that the re-combustion of methane can reduce the temperature at primary combustion zone, but increase the temperatures at the re-combustion area and the furnace outlet. The NOx concentration at the furnace outlet reduces with the increasing methane gas ratio. Methane re-combustion can greatly benefit to the NOx emissions reduction.