Characteristics of high temperature C-CO2 gasification reactivity of Victorian brown coal char and its blends with high ash fusion temperature bituminous coal

Research output: Contribution to journalArticleResearchpeer-review

Abstract

This research paper explores the high temperature gasification reactivity of brown coal char and its potential for promoting the gasification of high-ash-fusion temperature bituminous coal under entrained-flow gasification conditions. Using thermogravimetric analysis (TGA), the C-CO2 gasification reactivity for a brown coal char and two bituminous coals with low/high ash contents and high ash fusion temperatures, as well as their blends were investigated over a temperature range of 900–1300 °C and atmospheric pressure. The nth order reaction rate equations were fitted based on a random pore model of the gasification reaction. The results show that the brown coal char has a high reactivity compared to the two bituminous coals, which mainly due to its more porous physical structure, whereas the catalytic effect of its ash-forming elements is insignificant above 1100 °C. The intrinsic activation energy was determined to be 154.5 kJ/mol for the brown coal char, which is lower than the higher activation energy of the two bituminous coals of 189.61 kJ/mol and 196.02 kJ/mol. Upon increasing the bituminous coal fraction, the activation energy increases stably due to the increased ash amount and increased molten ash that inhibit the gas diffusion. For the low-ash bituminous coal blended with 20–40% brown coal char, its C-CO2 reactivity is maximised at 1200 °C when the ash turns soft. Upon further increase of the temperature, its reactivity decreases due to the enhanced melting of the ash. Instead, for the high-ash bituminous coal, its addition of 20% to brown coal char is beneficial in decreasing the overall ash melting temperature. The C-CO2 gasification reactivity of 20% high-ash bituminous coal blended with brown coal char is maximised at 1100 °C when the ash turns soft and is minimised at 1200 °C when the ash is fully molten.

Original languageEnglish
Pages (from-to)352-365
Number of pages14
JournalFuel
Volume202
DOIs
Publication statusPublished - 15 Aug 2017

Keywords

  • Ash melting
  • Blend gasification
  • Brown coal char
  • High-temperature C-CO gasification reactivity

Cite this

@article{65f070f6d9124f0a9cb449318acbd8e3,
title = "Characteristics of high temperature C-CO2 gasification reactivity of Victorian brown coal char and its blends with high ash fusion temperature bituminous coal",
abstract = "This research paper explores the high temperature gasification reactivity of brown coal char and its potential for promoting the gasification of high-ash-fusion temperature bituminous coal under entrained-flow gasification conditions. Using thermogravimetric analysis (TGA), the C-CO2 gasification reactivity for a brown coal char and two bituminous coals with low/high ash contents and high ash fusion temperatures, as well as their blends were investigated over a temperature range of 900–1300 °C and atmospheric pressure. The nth order reaction rate equations were fitted based on a random pore model of the gasification reaction. The results show that the brown coal char has a high reactivity compared to the two bituminous coals, which mainly due to its more porous physical structure, whereas the catalytic effect of its ash-forming elements is insignificant above 1100 °C. The intrinsic activation energy was determined to be 154.5 kJ/mol for the brown coal char, which is lower than the higher activation energy of the two bituminous coals of 189.61 kJ/mol and 196.02 kJ/mol. Upon increasing the bituminous coal fraction, the activation energy increases stably due to the increased ash amount and increased molten ash that inhibit the gas diffusion. For the low-ash bituminous coal blended with 20–40{\%} brown coal char, its C-CO2 reactivity is maximised at 1200 °C when the ash turns soft. Upon further increase of the temperature, its reactivity decreases due to the enhanced melting of the ash. Instead, for the high-ash bituminous coal, its addition of 20{\%} to brown coal char is beneficial in decreasing the overall ash melting temperature. The C-CO2 gasification reactivity of 20{\%} high-ash bituminous coal blended with brown coal char is maximised at 1100 °C when the ash turns soft and is minimised at 1200 °C when the ash is fully molten.",
keywords = "Ash melting, Blend gasification, Brown coal char, High-temperature C-CO gasification reactivity",
author = "Baiqian Dai and Andrew Hoadley and Lian Zhang",
year = "2017",
month = "8",
day = "15",
doi = "10.1016/j.fuel.2017.04.044",
language = "English",
volume = "202",
pages = "352--365",
journal = "Fuel",
issn = "0016-2361",
publisher = "Elsevier",

}

TY - JOUR

T1 - Characteristics of high temperature C-CO2 gasification reactivity of Victorian brown coal char and its blends with high ash fusion temperature bituminous coal

AU - Dai, Baiqian

AU - Hoadley, Andrew

AU - Zhang, Lian

PY - 2017/8/15

Y1 - 2017/8/15

N2 - This research paper explores the high temperature gasification reactivity of brown coal char and its potential for promoting the gasification of high-ash-fusion temperature bituminous coal under entrained-flow gasification conditions. Using thermogravimetric analysis (TGA), the C-CO2 gasification reactivity for a brown coal char and two bituminous coals with low/high ash contents and high ash fusion temperatures, as well as their blends were investigated over a temperature range of 900–1300 °C and atmospheric pressure. The nth order reaction rate equations were fitted based on a random pore model of the gasification reaction. The results show that the brown coal char has a high reactivity compared to the two bituminous coals, which mainly due to its more porous physical structure, whereas the catalytic effect of its ash-forming elements is insignificant above 1100 °C. The intrinsic activation energy was determined to be 154.5 kJ/mol for the brown coal char, which is lower than the higher activation energy of the two bituminous coals of 189.61 kJ/mol and 196.02 kJ/mol. Upon increasing the bituminous coal fraction, the activation energy increases stably due to the increased ash amount and increased molten ash that inhibit the gas diffusion. For the low-ash bituminous coal blended with 20–40% brown coal char, its C-CO2 reactivity is maximised at 1200 °C when the ash turns soft. Upon further increase of the temperature, its reactivity decreases due to the enhanced melting of the ash. Instead, for the high-ash bituminous coal, its addition of 20% to brown coal char is beneficial in decreasing the overall ash melting temperature. The C-CO2 gasification reactivity of 20% high-ash bituminous coal blended with brown coal char is maximised at 1100 °C when the ash turns soft and is minimised at 1200 °C when the ash is fully molten.

AB - This research paper explores the high temperature gasification reactivity of brown coal char and its potential for promoting the gasification of high-ash-fusion temperature bituminous coal under entrained-flow gasification conditions. Using thermogravimetric analysis (TGA), the C-CO2 gasification reactivity for a brown coal char and two bituminous coals with low/high ash contents and high ash fusion temperatures, as well as their blends were investigated over a temperature range of 900–1300 °C and atmospheric pressure. The nth order reaction rate equations were fitted based on a random pore model of the gasification reaction. The results show that the brown coal char has a high reactivity compared to the two bituminous coals, which mainly due to its more porous physical structure, whereas the catalytic effect of its ash-forming elements is insignificant above 1100 °C. The intrinsic activation energy was determined to be 154.5 kJ/mol for the brown coal char, which is lower than the higher activation energy of the two bituminous coals of 189.61 kJ/mol and 196.02 kJ/mol. Upon increasing the bituminous coal fraction, the activation energy increases stably due to the increased ash amount and increased molten ash that inhibit the gas diffusion. For the low-ash bituminous coal blended with 20–40% brown coal char, its C-CO2 reactivity is maximised at 1200 °C when the ash turns soft. Upon further increase of the temperature, its reactivity decreases due to the enhanced melting of the ash. Instead, for the high-ash bituminous coal, its addition of 20% to brown coal char is beneficial in decreasing the overall ash melting temperature. The C-CO2 gasification reactivity of 20% high-ash bituminous coal blended with brown coal char is maximised at 1100 °C when the ash turns soft and is minimised at 1200 °C when the ash is fully molten.

KW - Ash melting

KW - Blend gasification

KW - Brown coal char

KW - High-temperature C-CO gasification reactivity

UR - http://www.scopus.com/inward/record.url?scp=85017704257&partnerID=8YFLogxK

U2 - 10.1016/j.fuel.2017.04.044

DO - 10.1016/j.fuel.2017.04.044

M3 - Article

VL - 202

SP - 352

EP - 365

JO - Fuel

JF - Fuel

SN - 0016-2361

ER -