Influence of Thermal Properties of Wall Deposits on Performance of Pulverized Fuel Fired Boiler Combustion Chambers

Richter, Wolfgang; Payne, R.; Heap, M.P.

doi:10.1021/bk-1986-0301.ch026

Cited by 5 publications

(2 citation statements)

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“…In the actual operation of coal-fired boiler furnaces, ash that arises even in complete combustion inevitably forms deposits on the wall and heat exchanger surfaces of the furnace due to mineral and slag formation during combustion [ 22 ]. These ash deposits decrease the boiler performance by being the leading obstacles to heat transfer [ 23 , 24 , 25 ]. Specifically, the ash deposits influence thermal radiation significantly because they alter wall emissivity [ 26 , 27 ].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Irreversibility Analysis of Thermal Radiation in Coal-Fired Furnace: Effect of Coal Ash Deposits

Zhang

Lou

2023

Materials

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In this paper, a three-dimensional (3-D) high-temperature furnace filled with a gas-solid medium was investigated, and the radiative transfer equation and the radiative entropy transfer equation in the chamber were applied in order to analyze the effect of coal deposits on thermal radiation. The heat flux on the walls of the furnace and the entropy generation rate were determined due to the irreversibility of the radiative heat transfer process in the furnace. Furthermore, the effect of ash deposits on the wall surface on the irreversibility of the radiation heat transfer process was investigated. The numerical results show that when burning bituminous and sub-bituminous coal, ash deposits in the furnace led to a 48.2% and 63.2% decrease in wall radiative heat flux and a 9.1% and 12.4% decrease in the radiative entropy rate, respectively. The ash deposits also led to an increase in the entropy generation number and a decrease in the thermodynamic efficiency of the radiative heat transfer process in the furnace.

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Section: Introductionmentioning

confidence: 99%

Thermodynamic Irreversibility Analysis of Thermal Radiation in Coal-Fired Furnace: Effect of Coal Ash Deposits

Zhang

Lou

2023

Materials

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“…The heterogeneous composition of coal and ash particles make these phenomena even more difficult to understand because these differences affect how the particle sticks to walls, sinters, and/or aggregates to other particles and how the layers of particles are formed . There is enough motivation (financial and otherwise) to understand the mechanisms and characteristics that control deposition phenomena, as reflected by literature dating back 30+ years. − The general consensus agrees that deposition affects two main heat-transfer properties that influence the overall behavior of a pulverized-coal combustion system: emissivity and thermal conductivity. In this paper, we briefly mention the role of the thermal conductivity but the main focus is emissivity and in the ways to predict this property in the presence of ash deposits on the boiler walls.…”

Section: Introductionmentioning

confidence: 99%

Radiative Properties of Coal Ash Deposits with Sintering Effects

et al. 2019

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The heat-transfer characteristics in the fireside of a pulverized-coal furnace are affected, among other factors, by the physical and chemical characteristics of the ash deposits. Indeed, the physical state of the ash deposits and their chemical composition determine the radiative and conductive properties of the furnace walls. Particularly, several complex mechanisms are involved in the radiative heat-transfer process at the walls that restricts the absorption of the incident radiation of the flame, particles, and hot gases. These mechanisms involve dependencies on the radiation spectrum due to the ash chemical composition and ash-sintering effects that enhance or hinder the overall heat transfer. In this paper, we discuss the complex mechanisms that describe the heat exchange in the presence of ash deposits and their impact on the prediction of the wall emissivity and ultimately the wall heat transfer in a real system.

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Emittance of Layers of Uniform Ash-Like Slag Particles: Spectral Nature and Effects of Particle Size, Composition, and Heating

Bhattacharya

Wall

Gupta

et al. 1996

Applications of Advanced Technology to Ash-Related Problems in Boilers

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Influence of Thermal Properties of Wall Deposits on Performance of Pulverized Fuel Fired Boiler Combustion Chambers

Cited by 5 publications

References 0 publications

Thermodynamic Irreversibility Analysis of Thermal Radiation in Coal-Fired Furnace: Effect of Coal Ash Deposits

Thermodynamic Irreversibility Analysis of Thermal Radiation in Coal-Fired Furnace: Effect of Coal Ash Deposits

Radiative Properties of Coal Ash Deposits with Sintering Effects

Emittance of Layers of Uniform Ash-Like Slag Particles: Spectral Nature and Effects of Particle Size, Composition, and Heating

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