CFD modeling of flow, combustion and NOx emission in a wall-fired boiler at different low-load operating conditions

Wang, Haopeng; Jin, Haoze; Yang, Zhi; Deng, Shanshan; Wu, Xuehong; An, Jingxue; Sheng, Ranran; Ti, Shuguang

doi:10.1016/j.applthermaleng.2023.121824

Cited by 12 publications

(4 citation statements)

References 32 publications

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“…Describing the particle phase involved employing the Lagrange method, and a mathematical model was developed using this approach. The Lagrange method treats fluid and particles as inter-penetrable continuous media, providing simplified calculations while effectively tracking complex particle trajectories [39].…”

Section: Methodsmentioning

confidence: 99%

Numerical Study of Supercritical Opposed Wall-Fired Boiler Furnace Temperature and High-Temperature Heating Surface Stress under Variable Load Operation

Du,

Li,

Zhao

et al. 2024

Energies

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The opposed wall-fired boiler is widely used in Chinese power plants due to its adaptability. However, deviations from design conditions can cause the reduction of combustion efficiency and combustion stability, and the overheating of heating surfaces. This study conducted numerical simulations on a 600 MW supercritical opposed wall-fired boiler at 75%, 50%, and 30% Turbine Heat Acceptance (THA) load conditions. The variation of temperature field and heat flux in the furnace under different loads, and parameters such as distributions of heat flux, temperature, and the stress of the high-temperature heating surface are analyzed. Results indicate that reducing the load from 75% to 30% THA lowers the furnace outlet temperature from 1158 to 1009 K and reduces the average gas temperature of the high-temperature heating surface from 1800 to 1570 K. Under a high load, the maximum heat flux concentrates on the side water-cooled wall of the combustion zone. However, when the load decreases, the heat absorption shifts towards the main combustion zone. Furthermore, under a high load, the average wall temperature of the high-temperature heating surface remains at 1600 K with a uniform temperature distribution. In contrast, when the load drops to 30% THA, significant temperature differences appear on the heating surface, with a maximum difference of 400 K. This leads to excessive expansion and slagging on the high-temperature heating surface, particularly in the middle and lower sections, due to the increased stress. These findings offer valuable insights for optimizing the combustion characteristics of opposed wall-fired boilers and preventing overtemperature explosions on the platen heating surface.

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Section: Methodsmentioning

confidence: 99%

Numerical Study of Supercritical Opposed Wall-Fired Boiler Furnace Temperature and High-Temperature Heating Surface Stress under Variable Load Operation

Du,

Li,

Zhao

et al. 2024

Energies

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“…MSW incineration mainly produces fuel-based NO x and thermal NO x . Fuel-based NO x generation is calculated using additional transport equations, whereas thermal NO x is mainly produced by oxidation of N 2 at high temperatures and is described by the Zeldovich mechanism normalN 2 + normalO → normalN + NO normalN + normalO 2 → normalO + NO normalN + OH → normalH + NO …”

Section: Mathematical Model and Boundary Conditionsmentioning

confidence: 99%

“…Fuel-based NO x generation is calculated using additional transport equations, whereas thermal NO x is mainly produced by oxidation of N 2 at high temperatures and is described by the Zeldovich mechanism. 18 …”

Section: Mathematical Model and Boundary Conditionsmentioning

confidence: 99%

Numerical Simulation Study on Combustion of Low Calorific Value Waste Blended with Biomass

Huang,

Gong,

Peng

et al. 2024

ACS Omega

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Numerical simulations of a 600 t/day waste incinerator was carried out using the fluid dynamic incinerator code and Fluent to evaluate the effect of biomass blending on furnace temperature, pollutant generation, and selective noncatalytic− reduction (SNCR) denitrification when treating low calorific−value waste. The results show that as the biomass blending ratio increases, the water content gradually decreases, the calorific value increases, and the maximum temperature of the incinerator gradually increases from 1227 to 1408 K, while the content of exported NO x increases from 579 to 793 mg/Nm 3 ; during the combustion of low-quality waste, the residence time of the flue gas in the high-temperature region (above 1123 K) is 1.62 s. When the biomass blending ratio exceeds 20%, the residence time of the flue gas in the hightemperature region is more than 2 s, which can effectively curb the generation of dioxin. When the biomass blending ratio is 20%, and the normalized stoichiometric ratio (2n urea /n NO ) of urea injected into the SNCR is 1.1, the NO x concentration at the outlet is 230.08 mg/Nm 3 , which satisfies the NO x emission standard of less than 250 mg/Nm 3 .

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“…Remarkably, the simulation outcomes of the optimization scheme demonstrated close alignment with field test results. Furthermore, several scholars [24][25][26][27][28] have demonstrated that by implementing a well-designed super-combustion air (OFA) distribution, boilers can exhibit robust performance under low-load conditions. This paper conducts numerical simulations to analyze the combustion behavior of a 660 MW tangential coal powder boiler operating at 15% and 20% of its rated load within a specific power plant.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Combustion in 660 MW Tangentially Fired Pulverized Coal Boiler on Ultra-Low Load Operation

Jing,

Guo,

Wang

2024

FHMT

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In this paper, the combustion conditions in the boiler furnace of a 660 MW tangential fired pulverized coal boiler are numerically simulated at 15% and 20% rated loads, to study the flexibility of coal-fired power units on ultra-low load operation. The numerical results show that the boiler can operate safely at 15% and 20% ultra-low loads, and the combustion condition in the furnace is better at 20% load, and the tangent circles formed by each characteristic section in the furnace are better, and when the boiler load is decreased to 15%, the tangent circles in the furnace begin to deteriorate. The average flue gas temperature of different areas of the furnace shows that when the boiler furnace operates under ultra-low load conditions, the average smoke temperature of the cold ash hopper at 20% load is basically the same as the average smoke temperature at 15% load; in the burner area, the average smoke temperature of the cold ash hopper at 20% load is about 50 K higher than that at 15% load; in the burned out area, the average smoke temperature of the cold ash hopper at 20% load is slightly higher than that at 15% load. The average temperature of flue gas in the furnace showed a tendency to increase rapidly with the height of the furnace, then slow down and fluctuate the temperature in the burner area, and finally increase slightly in the burnout area due to the further combustion of combustible components to release heat, and then began to decrease.

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CFD modeling of flow, combustion and NOx emission in a wall-fired boiler at different low-load operating conditions

Cited by 12 publications

References 32 publications

Numerical Study of Supercritical Opposed Wall-Fired Boiler Furnace Temperature and High-Temperature Heating Surface Stress under Variable Load Operation

Numerical Study of Supercritical Opposed Wall-Fired Boiler Furnace Temperature and High-Temperature Heating Surface Stress under Variable Load Operation

Numerical Simulation Study on Combustion of Low Calorific Value Waste Blended with Biomass

Numerical Simulation of Combustion in 660 MW Tangentially Fired Pulverized Coal Boiler on Ultra-Low Load Operation

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