An experimental investigation into mineral transformation, particle agglomeration and ash deposition during combustion of Zhundong lignite in a laboratory-scale circulating fluidized bed

Zhuo Liu, Jianbo Li, Quanhai Wang, Xiaofeng Lu, Yuanyuan Zhang, Mingming Zhu, Zhezi Zhang, Dongke Zhang

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The characteristics and mechanisms of inorganics and mineral transformation, particle agglomeration and ash deposition during Zhundong lignite combustion in a 0.2 t/d lab-scale circulating fluidized bed (CFB) furnace were experimentally investigated. A sample of Zhundong lignite with particle size <3 mm was combusted in the CFB operating at 950 degrees C. An ash deposition probe installed at the upper outlet of the cyclone maintained at 550 degrees C was used to simulate ash deposition. The bottom ash, ash deposit on the probe, and fly ash were collected and analysed using SEM-EDX, XRD, ICP-OES and an ash fusion analyser. It was found that the bottom ash was composed of discrete particles of SiO2, Fe2O3, and NaAlSiO4 and etc., among which particles rich in Fe and Na had agglomerated. The deposit on the upwind surface of the probe showed a layered structure: a sintered cone-shape inner-layer rich in micron-sized Ca- and Na-bearing minerals, and a loose coarse-grained outer-layer dominated by silicates and aluminosilicates. The inner-layer was believed to have initiated the ash deposition while the outer-layer was believed to have been captured by the initiating layer. XRD analysis confirmed the presence of Ca- and Na-bearing minerals including CaSO4, NaAlSiO4, Na2SO4 and Na2Si2O5 of low melting-points in the deposit. The fly ash was composed of ash particles or clusters enriched in CaSO4 and Ca2Al2SiO7. Furthermore, ICP analysis revealed that Na was enriched in the deposit, while Fe was enriched in the bottom ash, both of which however were comparably less in the fly ash. Consequently, the fusion temperatures of the bottom ash and deposit were lower than that of the fly ash. In addition, mineral interactions between bed materials and Zhundong lignite ashes including Na capture by aluminosilicate were identified, affecting the partitioning of alkali and alkali earth during combustion and ash deposition in CFB.

Original languageEnglish
Pages (from-to)458-468
Number of pages11
JournalFuel
Volume243
DOIs
Publication statusPublished - 1 May 2019

Cite this

@article{9a922a3442da4805b4ca53ce6a11444c,
title = "An experimental investigation into mineral transformation, particle agglomeration and ash deposition during combustion of Zhundong lignite in a laboratory-scale circulating fluidized bed",
abstract = "The characteristics and mechanisms of inorganics and mineral transformation, particle agglomeration and ash deposition during Zhundong lignite combustion in a 0.2 t/d lab-scale circulating fluidized bed (CFB) furnace were experimentally investigated. A sample of Zhundong lignite with particle size <3 mm was combusted in the CFB operating at 950 degrees C. An ash deposition probe installed at the upper outlet of the cyclone maintained at 550 degrees C was used to simulate ash deposition. The bottom ash, ash deposit on the probe, and fly ash were collected and analysed using SEM-EDX, XRD, ICP-OES and an ash fusion analyser. It was found that the bottom ash was composed of discrete particles of SiO2, Fe2O3, and NaAlSiO4 and etc., among which particles rich in Fe and Na had agglomerated. The deposit on the upwind surface of the probe showed a layered structure: a sintered cone-shape inner-layer rich in micron-sized Ca- and Na-bearing minerals, and a loose coarse-grained outer-layer dominated by silicates and aluminosilicates. The inner-layer was believed to have initiated the ash deposition while the outer-layer was believed to have been captured by the initiating layer. XRD analysis confirmed the presence of Ca- and Na-bearing minerals including CaSO4, NaAlSiO4, Na2SO4 and Na2Si2O5 of low melting-points in the deposit. The fly ash was composed of ash particles or clusters enriched in CaSO4 and Ca2Al2SiO7. Furthermore, ICP analysis revealed that Na was enriched in the deposit, while Fe was enriched in the bottom ash, both of which however were comparably less in the fly ash. Consequently, the fusion temperatures of the bottom ash and deposit were lower than that of the fly ash. In addition, mineral interactions between bed materials and Zhundong lignite ashes including Na capture by aluminosilicate were identified, affecting the partitioning of alkali and alkali earth during combustion and ash deposition in CFB.",
keywords = "Alkali and alkali earth metals, Ash deposition, Circulating fluidized bed combustion (CFBC), Particle agglomerate, Zhundong lignite, HIGH-SODIUM, COAL, GASIFICATION, EMISSION, DEFLUIDISATION, TEMPERATURE, PERFORMANCE, ADDITIVES, BEHAVIOR, FUSION",
author = "Zhuo Liu and Jianbo Li and Quanhai Wang and Xiaofeng Lu and Yuanyuan Zhang and Mingming Zhu and Zhezi Zhang and Dongke Zhang",
year = "2019",
month = "5",
day = "1",
doi = "10.1016/j.fuel.2019.01.134",
language = "English",
volume = "243",
pages = "458--468",
journal = "Fuel",
issn = "0016-2361",
publisher = "Elsevier",

}

An experimental investigation into mineral transformation, particle agglomeration and ash deposition during combustion of Zhundong lignite in a laboratory-scale circulating fluidized bed. / Liu, Zhuo; Li, Jianbo; Wang, Quanhai; Lu, Xiaofeng; Zhang, Yuanyuan; Zhu, Mingming; Zhang, Zhezi; Zhang, Dongke.

In: Fuel, Vol. 243, 01.05.2019, p. 458-468.

Research output: Contribution to journalArticle

TY - JOUR

T1 - An experimental investigation into mineral transformation, particle agglomeration and ash deposition during combustion of Zhundong lignite in a laboratory-scale circulating fluidized bed

AU - Liu, Zhuo

AU - Li, Jianbo

AU - Wang, Quanhai

AU - Lu, Xiaofeng

AU - Zhang, Yuanyuan

AU - Zhu, Mingming

AU - Zhang, Zhezi

AU - Zhang, Dongke

PY - 2019/5/1

Y1 - 2019/5/1

N2 - The characteristics and mechanisms of inorganics and mineral transformation, particle agglomeration and ash deposition during Zhundong lignite combustion in a 0.2 t/d lab-scale circulating fluidized bed (CFB) furnace were experimentally investigated. A sample of Zhundong lignite with particle size <3 mm was combusted in the CFB operating at 950 degrees C. An ash deposition probe installed at the upper outlet of the cyclone maintained at 550 degrees C was used to simulate ash deposition. The bottom ash, ash deposit on the probe, and fly ash were collected and analysed using SEM-EDX, XRD, ICP-OES and an ash fusion analyser. It was found that the bottom ash was composed of discrete particles of SiO2, Fe2O3, and NaAlSiO4 and etc., among which particles rich in Fe and Na had agglomerated. The deposit on the upwind surface of the probe showed a layered structure: a sintered cone-shape inner-layer rich in micron-sized Ca- and Na-bearing minerals, and a loose coarse-grained outer-layer dominated by silicates and aluminosilicates. The inner-layer was believed to have initiated the ash deposition while the outer-layer was believed to have been captured by the initiating layer. XRD analysis confirmed the presence of Ca- and Na-bearing minerals including CaSO4, NaAlSiO4, Na2SO4 and Na2Si2O5 of low melting-points in the deposit. The fly ash was composed of ash particles or clusters enriched in CaSO4 and Ca2Al2SiO7. Furthermore, ICP analysis revealed that Na was enriched in the deposit, while Fe was enriched in the bottom ash, both of which however were comparably less in the fly ash. Consequently, the fusion temperatures of the bottom ash and deposit were lower than that of the fly ash. In addition, mineral interactions between bed materials and Zhundong lignite ashes including Na capture by aluminosilicate were identified, affecting the partitioning of alkali and alkali earth during combustion and ash deposition in CFB.

AB - The characteristics and mechanisms of inorganics and mineral transformation, particle agglomeration and ash deposition during Zhundong lignite combustion in a 0.2 t/d lab-scale circulating fluidized bed (CFB) furnace were experimentally investigated. A sample of Zhundong lignite with particle size <3 mm was combusted in the CFB operating at 950 degrees C. An ash deposition probe installed at the upper outlet of the cyclone maintained at 550 degrees C was used to simulate ash deposition. The bottom ash, ash deposit on the probe, and fly ash were collected and analysed using SEM-EDX, XRD, ICP-OES and an ash fusion analyser. It was found that the bottom ash was composed of discrete particles of SiO2, Fe2O3, and NaAlSiO4 and etc., among which particles rich in Fe and Na had agglomerated. The deposit on the upwind surface of the probe showed a layered structure: a sintered cone-shape inner-layer rich in micron-sized Ca- and Na-bearing minerals, and a loose coarse-grained outer-layer dominated by silicates and aluminosilicates. The inner-layer was believed to have initiated the ash deposition while the outer-layer was believed to have been captured by the initiating layer. XRD analysis confirmed the presence of Ca- and Na-bearing minerals including CaSO4, NaAlSiO4, Na2SO4 and Na2Si2O5 of low melting-points in the deposit. The fly ash was composed of ash particles or clusters enriched in CaSO4 and Ca2Al2SiO7. Furthermore, ICP analysis revealed that Na was enriched in the deposit, while Fe was enriched in the bottom ash, both of which however were comparably less in the fly ash. Consequently, the fusion temperatures of the bottom ash and deposit were lower than that of the fly ash. In addition, mineral interactions between bed materials and Zhundong lignite ashes including Na capture by aluminosilicate were identified, affecting the partitioning of alkali and alkali earth during combustion and ash deposition in CFB.

KW - Alkali and alkali earth metals

KW - Ash deposition

KW - Circulating fluidized bed combustion (CFBC)

KW - Particle agglomerate

KW - Zhundong lignite

KW - HIGH-SODIUM

KW - COAL

KW - GASIFICATION

KW - EMISSION

KW - DEFLUIDISATION

KW - TEMPERATURE

KW - PERFORMANCE

KW - ADDITIVES

KW - BEHAVIOR

KW - FUSION

U2 - 10.1016/j.fuel.2019.01.134

DO - 10.1016/j.fuel.2019.01.134

M3 - Article

VL - 243

SP - 458

EP - 468

JO - Fuel

JF - Fuel

SN - 0016-2361

ER -