Evaluation of performance of Anglo-Mafube bituminous South African coal in 550MW opposite-wall and 575MW tangential-fired utility boilers

Bar‐Ziv, Ezra; Saveliev, Roman; Korytnyi, Efim; Perelman, Miron; Chudnovsky, B.; Talanker, A.

doi:10.1016/j.fuproc.2014.01.026

Cited by 16 publications

(5 citation statements)

References 16 publications

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“…In the analysis of the collected residual solid, the consumption rates of the fixed carbon and volatile were calculated using eqs and , respectively, to analyze the consumption of the volatile and fixed carbon during the PC combustion process. ,,− The burnout rate was calculated using eq to analyze the combustion efficiency of bituminous coal. ,,, Here, CR V and CR FC are the consumption rates (%) of the volatile and fixed carbon of the dry coal, respectively; V i , FC i , and A i (%) are the contents of the volatile, fixed carbon, and ash of the dry collected residual solid, respectively; V 0 , FC 0 , and A 0 (%) are the contents of the volatile, fixed carbon, and ash of the dry coal, respectively. Here, BR c (%) is the burnout rate of the bituminous coal; A i is the ash content of the collected residual solid, and A 0 is the ash content of the dry coal.…”

Section: Methodsmentioning

confidence: 99%

Effect of the Primary Air Velocity on Ignition Characteristics of Bias Pulverized Coal Jets

Zeng

Sun

Yang³

et al. 2017

Energy Fuels

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Experiments were conducted under a hot condition of bituminous coal ignition in a 250 kW pilot-scale bias combustion simulator. The effects of the primary air velocity (PAV) on the ignition characteristics of bias pulverized coal jets in a reducing atmosphere were investigated to develop a better new burner for experimental bituminous coal. Multiple means of measurement and sampling were used for the axial and radial temperatures, flame spectrum, flue gas components, and residual solid inside the furnace. The standoff distance changed nonmonotonically between axial distances of 90 and 330 mm with increasing PAV and was shortest for a PAV of 16 m/s. The radiation heat transfer from the hot environment had more effect on the ignition than the convection heat transfer from high-temperature flue gas in the initial stage, while the convection heat transfer from the high-temperature flue gas played a greater role in the subsequent combustion of the char. At PAVs of 13 and 16 m/s, there was volatile and char homogeneous–heterogeneous combined ignition and one-mode combustion; at PAVs of 20 and 23 m/s, there was volatile-phase homogeneous ignition and two-mode combustion. The ignition of the fuel-rich jet lagged that of the fuel-lean jet at a PAV of 13 m/s. A PAV that is lower could not take advantage of bias pulverized coal combustion technology. The ignition of the fuel-rich jet was ahead of that of the fuel-lean jet at PAVs of 16, 20, and 23 m/s. At a PAV of 13 m/s, the position of stable ignition was the shortest, the temperature of stable ignition the highest, and the boundary of the stable flame the smallest. The PAV of 16 m/s provided the best ignition characteristics for bituminous bias pulverized coal jets, which is suitable to be selected as design PAV for the new burner development.

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Section: Methodsmentioning

confidence: 99%

Effect of the Primary Air Velocity on Ignition Characteristics of Bias Pulverized Coal Jets

Zeng

Sun

Yang³

et al. 2017

Energy Fuels

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“…The reason is that if the ignition characteristics of parallel bias PC jets in a reducing atmosphere were better, the combustion in the burning zone of PBCS was more intense, and more oxygen was consumed in the area near the nozzle of PC burner. Thus, when the air-to-coal stoichiometry in PBCS was 0.75, the reaction between oxygen and precursor of nitrogen oxides in the released volatiles was more limited during PC initial ignition process; therefore, the NO x formation concentrations gradually decreased, 49 which is not same as the NO x formation trend of normal PC combustion.…”

Section: Energy and Fuelsmentioning

confidence: 97%

Effects of Bias Concentration Ratio on Ignition Characteristics of Parallel Bias Pulverized Coal Jets

et al. 2017

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To further advance pulverized coal (PC) combustion theory and enable the rational development of horizontal bias combustion technology, combustion experiments were conducted in a 250 kW pilot-scale bias combustion simulator; multiple research means of combustion temperatures, flame spectra, burnout rates of residual solids, and NO x formation were used. A blend of sub-bituminous coal from Indonesia and bituminous coal from Australia was tested. The effects of bias concentration ratio (BCR) on the ignition characteristics of parallel bias PC jets in a reducing atmosphere were investigated. The results indicate that with increasing BCR for parallel bias PC jets, the standoff distance gradually decreased; the peaks of subsequent combustion temperature and visible-light intensity gradually increased; the continuous flame regions became advanced and concentrated; the flame stability gradually increased; the burnout rate gradually increased; the NO x formation gradually decreased, and the ignition characteristics gradually improved. Except at a BCR of 1, the PC ignition of the fuel-rich jet was better than that of the fuel-lean jet, and the continuous flame region of parallel bias PC jets leaned obviously in the direction of the fuel-rich jet. The bias combustion changed the ignition mode of primary air PC jets. There was homogeneous ignition mode at a BCR of 1; when BCR increased to no less than 3, the ignition mode changed to homogeneous–heterogeneous combined ignition, which is beneficial to the PC ignition conditions. Based on the research results in this paper, the recommended BCR for the design of a horizontal bias combustion PC burner is 4–5.

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“…Currently, numerical modelling of the combustion process for models including the combustion chamber together with the second boiler pass is quite commonly used [3][4][5]. As a rule, numerical calculations are carried out to modernize or optimize the combustion process in boilers [6][7][8][9][10][11] or tests on a real object [12]. On the other hand, with a few exceptions [13][14][15], not much research was carried out on boiler combustion for minimal boiler load.…”

Section: Introductionmentioning

confidence: 99%

Archives of Thermodynamics

Hernik,

Zabłocki

2020

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Power boilers should be characterized by high flexibility in terms of loads, which results from the demand for electricity. In addition to the flexibility of the boiler, it is also important for the boiler to operate under technical minimum conditions while maintaining harmful emissions standards. A boiler operating with a technical minimum should also exhibit a stable combustion process. The paper presents the results of numerical combustion research for the minimum load of the two-pass ultrasupercritical boiler with front wall swirl burners system. The combustion stability for the minimum boiler load of 40% for the three mill system configurations has been demonstrated. Based on the numerical tests carried out in terms of obtaining the most favourable combustion conditions and the emission of harmful substances, the most favourable of them cases was indicated.

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Evaluation of performance of Anglo-Mafube bituminous South African coal in 550MW opposite-wall and 575MW tangential-fired utility boilers

Cited by 16 publications

References 16 publications

Effect of the Primary Air Velocity on Ignition Characteristics of Bias Pulverized Coal Jets

Effect of the Primary Air Velocity on Ignition Characteristics of Bias Pulverized Coal Jets

Effects of Bias Concentration Ratio on Ignition Characteristics of Parallel Bias Pulverized Coal Jets

Archives of Thermodynamics

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