Effect of coal blending and ashing temperature on ash sintering and fusion characteristics during combustion of Zhundong lignite

Jianbo Li, Mingming Zhu, Zhezi Zhang, Kai Zhang, Guoqing Shen, Dongke Zhang

Research output: Contribution to journalArticle

  • 8 Citations

Abstract

Ash sintering and fusion characteristics of pulverised Zhundong lignite and its blends combusted at different temperatures in a muffle furnace were investigated. Zhundong lignite (ZL) was blended with an Australian bituminous (AB) and an Indonesian lignite (IL), respectively, at various blending ratios. The blends were then combusted in the muffle furnace in air at 550 °C and 815 °C. The sintering and fusion temperatures of the ashes of the blends were determined. In addition, the ashes prepared at 550 °C were further heated to 850 °C, 1050 °C and 1250 °C in air for different periods of time to study the mineralogical and morphological changes during the ash sintering and fusion. The results showed that the ZL ash at 815 °C was rich in basic oxides with Ca-bearing minerals anhydrite, calcium silicate and yeelimite being dominant, incurring relatively low ash sintering and fusion temperatures. Both AB and IL ashes, however, were rich in acidic oxides and dominant with refractory minerals such as quartz or mullite, leading to relatively high ash sintering and fusion temperatures. As the AB or IL addition ratio in the blend increased, the ash sintering temperature also increased, indicating that the addition of AB or IL into ZL decreased the ash sintering tendency. However, as the AB or IL addition ratio increased, the ash softening temperature (ST) and fluid temperature (FT) decreased first and then increased, reaching the lowest values at addition ratios of 40% for AB and 20% for IL. In addition, owing to the higher alkali and alkali earth contents in the forms of fluxing minerals, the sintering and fusion temperatures of the ash samples at 550 °C were correspondingly lower than those of the ashes at 815 °C. XRD and SEM-EDS analyses of the ash heated at 850 °C, 1050 °C and 1250 °C revealed that the sintering of the ZL ash was attributed to Na- and Cl-bearing minerals whereas the fusion of the ZL ash was attributed to the eutectics enriched with Ca, Al, Fe, and S. The addition of 20% AB into ZL resulted in the formation of hauyne, gehlenite and nepheline of low melting points and thus promoted the fusion of the ZL80AB20 ash, explaining why FT and HT of the ash initially decreased with increasing AB addition.

LanguageEnglish
Pages131-142
Number of pages12
JournalFuel
Volume195
DOIs
StatePublished - 1 May 2017

Fingerprint

Ashes
Coal
Lignite
Coal ash
Fusion reactions
Sintering
Temperature
Bearings (structural)
Minerals
Furnaces
Alkalies
Oxides

Cite this

@article{c710b6879479468e88166ce0937bd526,
title = "Effect of coal blending and ashing temperature on ash sintering and fusion characteristics during combustion of Zhundong lignite",
abstract = "Ash sintering and fusion characteristics of pulverised Zhundong lignite and its blends combusted at different temperatures in a muffle furnace were investigated. Zhundong lignite (ZL) was blended with an Australian bituminous (AB) and an Indonesian lignite (IL), respectively, at various blending ratios. The blends were then combusted in the muffle furnace in air at 550 °C and 815 °C. The sintering and fusion temperatures of the ashes of the blends were determined. In addition, the ashes prepared at 550 °C were further heated to 850 °C, 1050 °C and 1250 °C in air for different periods of time to study the mineralogical and morphological changes during the ash sintering and fusion. The results showed that the ZL ash at 815 °C was rich in basic oxides with Ca-bearing minerals anhydrite, calcium silicate and yeelimite being dominant, incurring relatively low ash sintering and fusion temperatures. Both AB and IL ashes, however, were rich in acidic oxides and dominant with refractory minerals such as quartz or mullite, leading to relatively high ash sintering and fusion temperatures. As the AB or IL addition ratio in the blend increased, the ash sintering temperature also increased, indicating that the addition of AB or IL into ZL decreased the ash sintering tendency. However, as the AB or IL addition ratio increased, the ash softening temperature (ST) and fluid temperature (FT) decreased first and then increased, reaching the lowest values at addition ratios of 40{\%} for AB and 20{\%} for IL. In addition, owing to the higher alkali and alkali earth contents in the forms of fluxing minerals, the sintering and fusion temperatures of the ash samples at 550 °C were correspondingly lower than those of the ashes at 815 °C. XRD and SEM-EDS analyses of the ash heated at 850 °C, 1050 °C and 1250 °C revealed that the sintering of the ZL ash was attributed to Na- and Cl-bearing minerals whereas the fusion of the ZL ash was attributed to the eutectics enriched with Ca, Al, Fe, and S. The addition of 20{\%} AB into ZL resulted in the formation of hauyne, gehlenite and nepheline of low melting points and thus promoted the fusion of the ZL80AB20 ash, explaining why FT and HT of the ash initially decreased with increasing AB addition.",
keywords = "Ash fusibility, Ash sintering, Ashing temperature, Coal blending, Mineral transformation, Zhundong lignite",
author = "Jianbo Li and Mingming Zhu and Zhezi Zhang and Kai Zhang and Guoqing Shen and Dongke Zhang",
year = "2017",
month = "5",
day = "1",
doi = "10.1016/j.fuel.2017.01.064",
language = "English",
volume = "195",
pages = "131--142",
journal = "Fuel",
issn = "0016-2361",
publisher = "Elsevier",

}

Effect of coal blending and ashing temperature on ash sintering and fusion characteristics during combustion of Zhundong lignite. / Li, Jianbo; Zhu, Mingming; Zhang, Zhezi; Zhang, Kai; Shen, Guoqing; Zhang, Dongke.

In: Fuel, Vol. 195, 01.05.2017, p. 131-142.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effect of coal blending and ashing temperature on ash sintering and fusion characteristics during combustion of Zhundong lignite

AU - Li,Jianbo

AU - Zhu,Mingming

AU - Zhang,Zhezi

AU - Zhang,Kai

AU - Shen,Guoqing

AU - Zhang,Dongke

PY - 2017/5/1

Y1 - 2017/5/1

N2 - Ash sintering and fusion characteristics of pulverised Zhundong lignite and its blends combusted at different temperatures in a muffle furnace were investigated. Zhundong lignite (ZL) was blended with an Australian bituminous (AB) and an Indonesian lignite (IL), respectively, at various blending ratios. The blends were then combusted in the muffle furnace in air at 550 °C and 815 °C. The sintering and fusion temperatures of the ashes of the blends were determined. In addition, the ashes prepared at 550 °C were further heated to 850 °C, 1050 °C and 1250 °C in air for different periods of time to study the mineralogical and morphological changes during the ash sintering and fusion. The results showed that the ZL ash at 815 °C was rich in basic oxides with Ca-bearing minerals anhydrite, calcium silicate and yeelimite being dominant, incurring relatively low ash sintering and fusion temperatures. Both AB and IL ashes, however, were rich in acidic oxides and dominant with refractory minerals such as quartz or mullite, leading to relatively high ash sintering and fusion temperatures. As the AB or IL addition ratio in the blend increased, the ash sintering temperature also increased, indicating that the addition of AB or IL into ZL decreased the ash sintering tendency. However, as the AB or IL addition ratio increased, the ash softening temperature (ST) and fluid temperature (FT) decreased first and then increased, reaching the lowest values at addition ratios of 40% for AB and 20% for IL. In addition, owing to the higher alkali and alkali earth contents in the forms of fluxing minerals, the sintering and fusion temperatures of the ash samples at 550 °C were correspondingly lower than those of the ashes at 815 °C. XRD and SEM-EDS analyses of the ash heated at 850 °C, 1050 °C and 1250 °C revealed that the sintering of the ZL ash was attributed to Na- and Cl-bearing minerals whereas the fusion of the ZL ash was attributed to the eutectics enriched with Ca, Al, Fe, and S. The addition of 20% AB into ZL resulted in the formation of hauyne, gehlenite and nepheline of low melting points and thus promoted the fusion of the ZL80AB20 ash, explaining why FT and HT of the ash initially decreased with increasing AB addition.

AB - Ash sintering and fusion characteristics of pulverised Zhundong lignite and its blends combusted at different temperatures in a muffle furnace were investigated. Zhundong lignite (ZL) was blended with an Australian bituminous (AB) and an Indonesian lignite (IL), respectively, at various blending ratios. The blends were then combusted in the muffle furnace in air at 550 °C and 815 °C. The sintering and fusion temperatures of the ashes of the blends were determined. In addition, the ashes prepared at 550 °C were further heated to 850 °C, 1050 °C and 1250 °C in air for different periods of time to study the mineralogical and morphological changes during the ash sintering and fusion. The results showed that the ZL ash at 815 °C was rich in basic oxides with Ca-bearing minerals anhydrite, calcium silicate and yeelimite being dominant, incurring relatively low ash sintering and fusion temperatures. Both AB and IL ashes, however, were rich in acidic oxides and dominant with refractory minerals such as quartz or mullite, leading to relatively high ash sintering and fusion temperatures. As the AB or IL addition ratio in the blend increased, the ash sintering temperature also increased, indicating that the addition of AB or IL into ZL decreased the ash sintering tendency. However, as the AB or IL addition ratio increased, the ash softening temperature (ST) and fluid temperature (FT) decreased first and then increased, reaching the lowest values at addition ratios of 40% for AB and 20% for IL. In addition, owing to the higher alkali and alkali earth contents in the forms of fluxing minerals, the sintering and fusion temperatures of the ash samples at 550 °C were correspondingly lower than those of the ashes at 815 °C. XRD and SEM-EDS analyses of the ash heated at 850 °C, 1050 °C and 1250 °C revealed that the sintering of the ZL ash was attributed to Na- and Cl-bearing minerals whereas the fusion of the ZL ash was attributed to the eutectics enriched with Ca, Al, Fe, and S. The addition of 20% AB into ZL resulted in the formation of hauyne, gehlenite and nepheline of low melting points and thus promoted the fusion of the ZL80AB20 ash, explaining why FT and HT of the ash initially decreased with increasing AB addition.

KW - Ash fusibility

KW - Ash sintering

KW - Ashing temperature

KW - Coal blending

KW - Mineral transformation

KW - Zhundong lignite

UR - http://www.scopus.com/inward/record.url?scp=85009872809&partnerID=8YFLogxK

U2 - 10.1016/j.fuel.2017.01.064

DO - 10.1016/j.fuel.2017.01.064

M3 - Article

VL - 195

SP - 131

EP - 142

JO - Fuel

T2 - Fuel

JF - Fuel

SN - 0016-2361

ER -