Occurrence and characteristics of abundant fine included mineral particles in Collie coal of Western Australia

Wu, Hongwei; Gao, Xiangpeng; Wee, Huiling; Ngu, Ling-Ngee; Ninomiya, Yoshihiko; Wang, Qunying

doi:10.1016/j.fuel.2017.11.118

Cited by 10 publications

(2 citation statements)

References 35 publications

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“…First, under current experimental conditions at 1300 °C, silica present in solid fuels can be reduced by CO or C to gaseous SiO, which can be then released into volatiles under local reducing conditions . This mechanism is more important for quartz-containing fuels, e.g., coals A, B, and C (because quartz is known to be present in the mineral matter in these fuels). Second, Si may also be released because of the ejection effect , via which Si-containing species can be carried over by the volatiles jet during rapid pyrolysis.…”

Section: Resultsmentioning

confidence: 99%

A New Method for Direct Determination of Char Yield during Solid Fuel Pyrolysis in Drop-Tube Furnace at High Temperature and Its Comparison with Ash Tracer Method

Liaw

2018

Energy Fuels

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A drop-tube furnace with a novel double-tube configuration was successfully developed to directly determine char yields during the pyrolysis of a wide range of solid fuels (mallee wood; mallee leaf; rice husk; biosolid; and subbituminous, bituminous, and anthracite coal) at a gas temperature of 1573 K. The char yield from pyrolysis of mallee wood and mallee leaf is <5%, ∼13% for rice husk, ∼16% for biosolid, ∼45% for subbituminous and bituminous coal, and ∼75% for anthracite coal. The retentions of Na, K, Mg, and Ca in biomass chars are <50%. About 35% of Na and K and ∼66–85% of P and refractory species in biosolid are retained in the char. In contrast, the retentions of major inorganic species in coal chars are >85%. This study shows using total ash as ash tracer results in 45–220% overestimation of char yields for biomass fuels and 13–27% for coals due to partial evaporation of ash. Similarly, selecting Na and K results in overestimation of biomass char yields by at least 2.5 times and selecting P leads to overestimation of biomass char yields by at least 80% because of substantial release of these species during pyrolysis. Similarly, selecting Mg, Ca, Al, Fe, Ti, or Si as tracer also results in inaccurate estimation of char yields due to partial release of these elements during pyrolysis. It is noted that for Si, which is often used as a tracer, the overestimation of char yields is 9–16% for coals but can be substantial (17–50%) for the case of biomass samples because of the substantial Si release during the pyrolysis of biomass (especially mallee wood with ∼32% of Si released). Clearly, for the solid fuels studied, no single element can be reliably used as tracer for calculating char yield during pyrolysis at high temperature. The new experimental method developed in this study fills this critical gap and enables direct determination of char yield during solid fuel pyrolysis in drop-tube furnace at high temperature.

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Section: Resultsmentioning

confidence: 99%

A New Method for Direct Determination of Char Yield during Solid Fuel Pyrolysis in Drop-Tube Furnace at High Temperature and Its Comparison with Ash Tracer Method

Liaw

2018

Energy Fuels

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“…From the partial enlarged curves shown in Figure 7, it was obvious that several broad new peaks occurred between diameters of 10 nm and 10 μm, and the main peaks located at 50 nm, 100 nm, 1 μm, 3 μm, and 8 μm. This might be attributed to the dissolution and removal of minerals (such as pyrite, calcite, and kaolinite) in coal after acidification, the size of which ranged from tens of nanometers to hundreds of microns (Brown et al, 2011;Liu S. et al, 2018;Wu et al, 2018). Pores that were partially blocked or occupied by minerals exposed and connected after acidification, thus significantly increasing the volume of large mesopores and macropores.…”

Section: Comprehensive Analysis Of Variedsized Pore Evolution Charact...mentioning

confidence: 99%

A comprehensive insight into the effects of acidification on varied-sized pores in different rank coals

et al. 2023

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Elucidating the evolution law of coal pore structure under acidification is crucial for guiding the practical application of acidizing technology and improving the production of coalbed methane. To comprehensively investigate the influence of acidification on varied-sized pores in different rank coals, in this study, fat coal, meagre coal and anthracite coal were collected and acidified with a mixed solution composed of hydrochloric acid (9 wt%) and hydrofluoric acid (3 wt%). An approach integrating low-pressure CO2 adsorption (LPGA-CO2), low-temperature N2 adsorption (LTGA-N2) and Mercury intrusion porosimetry (MIP) was adopted to fully characterize the varied-sized pore structure before and after acidification to eliminate the limitations of single method. The results demonstrated that acid treatment improved the pore opening degree and connectivity in coal, but had essentially no effect on the pore shape. After acidification, all the coal samples showed significant increases in the porosity and total pore volume, which was mainly contributed by the numerous newly formed large mesopores and macropores, especially the macropores (with an average contribution rate of 74.59%). Taken as a whole, acid treatment had the largest impact on macropores, followed by mesopores, and the smallest impact on micropores. In addition, the variation trend of total specific surface area (SSA) under acidification was primarily determined by micropores. For the three different rank coals selected in this study, the total SSA of fat coal (PM) was more easily affected by acidification and had the largest percentage increase after acid treatment, followed by anthracite coal (YM), while that of meagre coal (LA) decreased slightly. This difference was driven primarily by the different variation trend of micropore SSA in different rank coals. After acidification, the SSA of ultra-micropores and super-micropores all increased in fat coal (PM) and anthracite coal (YM), whereas for meagre coal (LA), although ultra-micropores SSA increased, super-micropores SSA decreased, which ultimately led to the slight decrease of its micropore SSA. Moreover, the total pore volume increment of coal was closely related to the macropore volume increment under acidification, but not significantly related to the coal maturity,which might indicate that, compared with coal rank, the mineral content in coal might be a more important consideration when measuring the applicability of acidification technology.

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Steam gasification of low-rank coal chars: Insights into the kinetic compensation effects and physical significance of kinetic parameters

Jena

Kumar

Liu

et al. 2022

Chemical Engineering Journal Advances

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Occurrence and characteristics of abundant fine included mineral particles in Collie coal of Western Australia

Cited by 10 publications

References 35 publications

A New Method for Direct Determination of Char Yield during Solid Fuel Pyrolysis in Drop-Tube Furnace at High Temperature and Its Comparison with Ash Tracer Method

A New Method for Direct Determination of Char Yield during Solid Fuel Pyrolysis in Drop-Tube Furnace at High Temperature and Its Comparison with Ash Tracer Method

A comprehensive insight into the effects of acidification on varied-sized pores in different rank coals

Steam gasification of low-rank coal chars: Insights into the kinetic compensation effects and physical significance of kinetic parameters

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