The influences of mineral behaviour on blended coal ash fusion characteristics

Qiu, Jianrong; Li, F.; Zheng, Ying; Chen, Zheng; Zhou, Huan

doi:10.1016/s0016-2361(99)00005-8

Cited by 72 publications

(37 citation statements)

References 5 publications

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“…The ash fusion temperatures initially decrease and then subsequently increase with the blending ratio (proportion of G100), before they reach the lowest temperatures in the vicinity of G30D70 (Figure 1). The ash fusion temperatures do not change linearly with bending ratios [23]. The fusibility of blended ashes as shown above is typically caused by eutectic melting.…”

Section: Ash Fusion Characteristicsmentioning

confidence: 82%

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Influence of Coal Blending on Ash Fusibility in Reducing Atmosphere

et al. 2015

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Abstract:Coal blending is an effective way to organize and control coal ash fusibility to meet different requirements of Coal-fired power plants. This study investigates three different eutectic processes and explains the mechanism of how coal blending affects ash fusibility. The blended ashes were prepared by hand-mixing two raw coal ashes at five blending ratios, G:D = 10:90 (G10D90), G:D= 20:80 (G20D80), G:D = 30:70 (G30D70), G:D = 40:60 (G40D60), and G:D = 50:50 (G50D50). The samples were heated at 900 °C, 1000 °C, 1100 °C, 1200 °C, and 1300 °C in reducing atmosphere. XRD and SEM/EDX were used to identify mineral transformations and eutectic processes. The eutectic processes were finally simulated with FactSage. Results show that the fusion temperatures of the blended ashes initially decrease and then increase with the blending ratio, a trend that is typical of eutectic melting. Eutectic phenomena are observed in D100, G10D90, and G30D70 in different degrees, which do not appear in G100 and G50D50 for the lack of eutectic reactants. The main eutectic reactants are gehlenite, magnetite, merwinite, and diopside. The FactSage simulation results show that the content discrepancy of merwinite and diopside in the ashes causes the inconsistent eutectic temperatures and eutectic degrees, in turn decrease the fusion temperature of the blended ash and then increase them with the blending ratio. OPEN ACCESSEnergies 2015, 8 4736

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Section: Ash Fusion Characteristicsmentioning

confidence: 82%

“…The mechanism of how coal blending affects ash fusibility requires further research. Moreover, the additive blending or coal blending can lower ash fusion temperature because a low-temperature eutectic mixture is generated [11,22,23,33]. On the contrary, the ash fusion temperature is expected to increase if a low-temperature eutectic mixture is not generated.…”

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confidence: 99%

Influence of Coal Blending on Ash Fusibility in Reducing Atmosphere

et al. 2015

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“…[7,21] As can be seen from points. Therefore, to decrease the AFT of high AFT coal, the optimum mixture ratio of blended ash is near the boundaries or triple points in CaO-SiO 2 -Al 2 O 3 or FeO-SiO 2 -Al 2 O 3 phase diagram.…”

Section: Relationship Between Afts Of Blended Ashes and Liquidus Tempmentioning

confidence: 96%

“…Each sample was then taken out and quenched in water quickly when temperature reached the predetermined temperature. [21,22] Quenched samples were dried and grounded into a powder of required particle size in a carnelian bowl, and the mineral composition of ash A, B and their blended coal ash A/B at various temperatures were obtained and analyzed by XRD analyses (D/Max PC 2550, Japan).…”

Section: Experiments On Ash By Xrdmentioning

confidence: 99%

“…Many researchers have been conducted to determine ash fusion characteristics of blended coal ash under combustion condition. [7,8,21] But a limited number of studies have been done to determine ash fusion characteristics and mineral transition mechanism of blended coal ash under gasification condition. A detailed knowledge of ash melting behavior and mineral transition of blended coal ash during coal gasification are specific properties that provide more information on suitability and safe operation of entrained flow gasifier when using blended coal.…”

Section: Introductionmentioning

confidence: 99%

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Mineral melting behavior of chinese blended coal ash under gasification condition

Zhou

Chen

et al. 2011

Asia-Pacific J Chem Eng

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The fusibility and mineral melting behavior of Chinese blended coal ash under gasification condition were studied by standard ash fusion temperature (AFT) test, X-ray diffraction (XRD), scanning electron microscope (SEM) and phase diagram theory. The experimental results show that the trend of blended ash's AFT is not linearly related to the blending ratios, but mirrors by changes in liquidus temperature from ternary phase diagram systems. The AFTs of those blended ashes whose main ash chemical compositions locate near the boundaries between two mineral regions or triple points are lower and change more evident than that of those blended ashes whose main ash chemical compositions are far away from the boundaries or triple points. With increasing mass fraction of low AFT ash in blended coal ash, the location of blended ash in ternary systems is changed from the mullite region to the anorthite region, as well as the dominant crystal mineral at deformation temperature (DT) is also transformed from mullite to anorthite via mullite-mullite and anorthite coexisting-anorthite. The fluxing minerals (anhydrite, wustite, albite, hercynite, augite) in low AFT ash can react with the refractory minerals (mullite, quartz) complicatedly to form new low-melting minerals (anorthite, hercynite, fayalite, gehlenite) at high temperature (HT) (1273-1403 K). These minerals can also interact to form eutectic mixtures in FeO-SiO 2 -Al 2 O 3 and CaO-SiO 2 -Al 2 O 3 systems and act as the most key factors for lowing melting mechanism of blended ash under gasification condition. 

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Coal‐Fired Power Generation Handbook

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The influences of mineral behaviour on blended coal ash fusion characteristics

Cited by 72 publications

References 5 publications

Influence of Coal Blending on Ash Fusibility in Reducing Atmosphere

Influence of Coal Blending on Ash Fusibility in Reducing Atmosphere

Mineral melting behavior of chinese blended coal ash under gasification condition

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