A phenomenological investigation into potassium migration and ash sintering characteristics during p.f. combustion of lignites with and without K2CO3 addition

Jiguang Zhang, Jianbo Li, Mingming Zhu, Zhezi Zhang, Baozhong Zhou, Guoqing Shen, Dongke Zhang

Research output: Contribution to journalArticle

Abstract

The morphology, mineralogy, and sintering characteristics of different lignite ashes prepared at varying temperatures in various lab-scale furnaces were investigated concerning the effect of K2CO3 addition. Lignites with and without K2CO3 addition were oxidised in a plasma asher at 423 K, a muffle furnace at 1073 K and a drop tube furnace (DTF) at 1773 K. Sintering temperatures of the ashes were determined, and their mineralogical and morphological features were analysed using XRD and SEM-EDS. Results showed that ash sintering temperature was increased as combustion temperature increased but decreased as K2CO3 addition ratio increased. Moreover, sintering temperatures of ashes rich in alumina oxide were the highest among the lignite ashes prepared at the same temperature. This trend remains valid for ashes of K2CO3-doped lignites. SEM-EDS results revealed that ashes from plasma asher were irregular and loose whereas the DTF ashes of the K2CO3-doped lignites were mostly spherical in shape, having incurred severe sintering. The lignite ashes from plasma asher tended to be enriched in boehmite and arcanite. At 1723 K as in DTF, new mineral phases including mullite and kalsilite were detected. When K2CO3 was added into lignites, kalsilite, microcline, and potassium sulphate of low melting-points were identified, consequently decreased ash sintering temperature.

Original languageEnglish
Pages (from-to)64-77
Number of pages14
JournalApplied Thermal Engineering
Volume148
DOIs
Publication statusPublished - 5 Feb 2019

Cite this

@article{3eb698a5dd964436bd4b3dbff8b0407f,
title = "A phenomenological investigation into potassium migration and ash sintering characteristics during p.f. combustion of lignites with and without K2CO3 addition",
abstract = "The morphology, mineralogy, and sintering characteristics of different lignite ashes prepared at varying temperatures in various lab-scale furnaces were investigated concerning the effect of K2CO3 addition. Lignites with and without K2CO3 addition were oxidised in a plasma asher at 423 K, a muffle furnace at 1073 K and a drop tube furnace (DTF) at 1773 K. Sintering temperatures of the ashes were determined, and their mineralogical and morphological features were analysed using XRD and SEM-EDS. Results showed that ash sintering temperature was increased as combustion temperature increased but decreased as K2CO3 addition ratio increased. Moreover, sintering temperatures of ashes rich in alumina oxide were the highest among the lignite ashes prepared at the same temperature. This trend remains valid for ashes of K2CO3-doped lignites. SEM-EDS results revealed that ashes from plasma asher were irregular and loose whereas the DTF ashes of the K2CO3-doped lignites were mostly spherical in shape, having incurred severe sintering. The lignite ashes from plasma asher tended to be enriched in boehmite and arcanite. At 1723 K as in DTF, new mineral phases including mullite and kalsilite were detected. When K2CO3 was added into lignites, kalsilite, microcline, and potassium sulphate of low melting-points were identified, consequently decreased ash sintering temperature.",
keywords = "Ash mineralogy, Ash morphology, Ash sintering, Mineral transformation, Potassium carbonate, Potassium migration, ALKALINE-EARTH METALS, STEAM GASIFICATION, COAL, BEHAVIOR, BIOMASS, TEMPERATURE, TRANSFORMATION, PYROLYSIS, CRITERION, MINERALS",
author = "Jiguang Zhang and Jianbo Li and Mingming Zhu and Zhezi Zhang and Baozhong Zhou and Guoqing Shen and Dongke Zhang",
year = "2019",
month = "2",
day = "5",
doi = "10.1016/j.applthermaleng.2018.11.033",
language = "English",
volume = "148",
pages = "64--77",
journal = "Applied Thermal Engineering",
issn = "1359-4311",
publisher = "Pergamon",

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A phenomenological investigation into potassium migration and ash sintering characteristics during p.f. combustion of lignites with and without K2CO3 addition. / Zhang, Jiguang; Li, Jianbo; Zhu, Mingming; Zhang, Zhezi; Zhou, Baozhong; Shen, Guoqing; Zhang, Dongke.

In: Applied Thermal Engineering, Vol. 148, 05.02.2019, p. 64-77.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A phenomenological investigation into potassium migration and ash sintering characteristics during p.f. combustion of lignites with and without K2CO3 addition

AU - Zhang, Jiguang

AU - Li, Jianbo

AU - Zhu, Mingming

AU - Zhang, Zhezi

AU - Zhou, Baozhong

AU - Shen, Guoqing

AU - Zhang, Dongke

PY - 2019/2/5

Y1 - 2019/2/5

N2 - The morphology, mineralogy, and sintering characteristics of different lignite ashes prepared at varying temperatures in various lab-scale furnaces were investigated concerning the effect of K2CO3 addition. Lignites with and without K2CO3 addition were oxidised in a plasma asher at 423 K, a muffle furnace at 1073 K and a drop tube furnace (DTF) at 1773 K. Sintering temperatures of the ashes were determined, and their mineralogical and morphological features were analysed using XRD and SEM-EDS. Results showed that ash sintering temperature was increased as combustion temperature increased but decreased as K2CO3 addition ratio increased. Moreover, sintering temperatures of ashes rich in alumina oxide were the highest among the lignite ashes prepared at the same temperature. This trend remains valid for ashes of K2CO3-doped lignites. SEM-EDS results revealed that ashes from plasma asher were irregular and loose whereas the DTF ashes of the K2CO3-doped lignites were mostly spherical in shape, having incurred severe sintering. The lignite ashes from plasma asher tended to be enriched in boehmite and arcanite. At 1723 K as in DTF, new mineral phases including mullite and kalsilite were detected. When K2CO3 was added into lignites, kalsilite, microcline, and potassium sulphate of low melting-points were identified, consequently decreased ash sintering temperature.

AB - The morphology, mineralogy, and sintering characteristics of different lignite ashes prepared at varying temperatures in various lab-scale furnaces were investigated concerning the effect of K2CO3 addition. Lignites with and without K2CO3 addition were oxidised in a plasma asher at 423 K, a muffle furnace at 1073 K and a drop tube furnace (DTF) at 1773 K. Sintering temperatures of the ashes were determined, and their mineralogical and morphological features were analysed using XRD and SEM-EDS. Results showed that ash sintering temperature was increased as combustion temperature increased but decreased as K2CO3 addition ratio increased. Moreover, sintering temperatures of ashes rich in alumina oxide were the highest among the lignite ashes prepared at the same temperature. This trend remains valid for ashes of K2CO3-doped lignites. SEM-EDS results revealed that ashes from plasma asher were irregular and loose whereas the DTF ashes of the K2CO3-doped lignites were mostly spherical in shape, having incurred severe sintering. The lignite ashes from plasma asher tended to be enriched in boehmite and arcanite. At 1723 K as in DTF, new mineral phases including mullite and kalsilite were detected. When K2CO3 was added into lignites, kalsilite, microcline, and potassium sulphate of low melting-points were identified, consequently decreased ash sintering temperature.

KW - Ash mineralogy

KW - Ash morphology

KW - Ash sintering

KW - Mineral transformation

KW - Potassium carbonate

KW - Potassium migration

KW - ALKALINE-EARTH METALS

KW - STEAM GASIFICATION

KW - COAL

KW - BEHAVIOR

KW - BIOMASS

KW - TEMPERATURE

KW - TRANSFORMATION

KW - PYROLYSIS

KW - CRITERION

KW - MINERALS

U2 - 10.1016/j.applthermaleng.2018.11.033

DO - 10.1016/j.applthermaleng.2018.11.033

M3 - Article

VL - 148

SP - 64

EP - 77

JO - Applied Thermal Engineering

JF - Applied Thermal Engineering

SN - 1359-4311

ER -