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STUDY ON THE IMPACT OF NEAR-WALL AIR SYSTEMS' WIND SPEED VARIATIONS ON THE COMBUSTION CHARACTERISTICS IN COAL-FIRED BOILERS

ABSTRACT

With increasingly strict national energy policies mandating ultra-low emissions for coal-fired power plants, the issue of high-temperature corrosion caused by reductive gases and elevated furnace temperatures has become critical. This study proposes the implementation of near-wall air systems on both sides of mid-furnace burners to mitigate water-cooled wall corrosion and enhance combustion efficiency. Using numerical simulation, the effects of a near-wall air system with a wind speed of 20 m/s were analyzed across the entire furnace. Results show that this approach reduces the average near-wall temperature by 4%, while increasing O₂ concentration in the combustion zone by approximately 6%, thus promoting more efficient combustion. Additionally, CO₂ and CO concentrations decrease by about 4.5% and 5.9%, respectively, effectively reducing reductive gases and alleviating high-temperature corrosion. NOx decreased significantly by 18.7%, indicating that air classification effectively suppressed NOx, which is a sign of efficient and low-nitrogen combustion. These findings offer a practical solution for improving boiler operational safety and efficiency under ultra-low emission requirements.

KEYWORDS

Pulverized-coal boiler, tangential firing, Near-wall wind technology, CFD, NOx emission

PAPER SUBMITTED: 2025-11-13

PAPER REVISED: 2026-01-05

PAPER ACCEPTED: 2026-01-29

PUBLISHED ONLINE: 2026-03-07

DOI REFERENCE: https://doi.org/10.2298/TSCI251113021C

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Study on the impact of near-wall air systems' wind speed variations on the combustion characteristics in coal-fired boilers

© 2026 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence

THERMAL SCIENCE

Find this paper on

Lihua Cai

Wangyongjia Zhong

Dianxu Ruan

Xiangfei Lin

Haifeng Fang

STUDY ON THE IMPACT OF NEAR-WALL AIR SYSTEMS' WIND SPEED VARIATIONS ON THE COMBUSTION CHARACTERISTICS IN COAL-FIRED BOILERS