Effect of high silicon-aluminum coal ashes on sintering and fusion characteristics of a potassium-rich biomass ash

Fan, Hongli; Guo, Qianqian; Guo, Mingxi

doi:10.1016/j.joei.2020.03.009

Cited by 33 publications

(8 citation statements)

References 41 publications

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“…Comparing the mineral composition of raw coal, roof rock, and mixed pyrolysis semicoke, it was found that after pyrolysis, orthoclase, pyrite, and kaolinite disappeared, and sanidine, pyrrhotite, and albite appeared. With the increase of temperature, orthoclase changes its crystal structure into sanidine with lower degree of order 24–26 . In the UCG pyrolysis process, kaolinite loses water to form metakaolinite.…”

Section: Resultsmentioning

confidence: 99%

Sequential transformation study of minerals during underground coal gasification: Promising to indirectly reflect the actual reaction condition

Wang

et al. 2021

Asia-Pacific J Chem Eng

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The mineralogical characteristics of underground coal gasification (UCG) residuals are closely related to the gasification conditions. The study of the mineral composition and transformation of ash and slag under different gasification conditions has important scientific significance for understanding the real gasification conditions, improving the utilization efficiency of coal, and identifying and controlling the environmental impact. In this paper, the sequential transformation of minerals under different temperature and atmosphere are studied by X‐ray diffraction (XRD) and FactSage software, and the elemental composition of the surface of the UCG ash and slag is characterized by SEM‐EDX. The results show that the main minerals in the semicoke are quartz (SiO2), illite (K1.5Al4(Si6.5Al1.5)O20(OH)4), and sanidine (KAlSi3O8). In the 900–1300°C reduction, ash, quartz, sanidine, hercynite (FeAl2O4), anorthite (CaAl2Si2O8), and mullite (Al6Si2O13) are the main minerals. The minerals in the oxidation residuals (1100–1500°C) are quartz, anorthite, hematite (Fe2O3), hercynite, cordierite (Fe2Al4Si5O18), and cristobalite. The reaction temperature has a significant effect on the changes in mineralogy. The reaction temperature is low during the pyrolysis process, and most changes involve only structural changes. With the reaction temperature increases, a series of reactions occur between different minerals. The reaction atmosphere also has a significant effect on the mineralogy. The research on the transformation of minerals in UCG residues can indirectly reflect the actual process of UCG, which can provide suggestions for the stable operation of the UCG process.

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Section: Resultsmentioning

confidence: 99%

Sequential transformation study of minerals during underground coal gasification: Promising to indirectly reflect the actual reaction condition

Wang

et al. 2021

Asia-Pacific J Chem Eng

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“…An AFT analyzer (Keli Co., Ltd., Hebi, China) was used to test AFT under an oxidation atmosphere in accordance with the ASTM D1857 standard [45]. According to the ash cone, four characteristic temperatures (DT, softening temperature (ST), hemispherical temperature (HT), and flow temperature (FT)) were identified.…”

Section: Ash Fusion Temperature Testmentioning

confidence: 99%

Regulation Mechanism of Solid Waste on Ash Fusion Characteristics of Sorghum Straw under O2/CO2 Atmosphere

Yang,

Li,

et al. 2023

Energies

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Co-combustion of solid waste and biomass can alleviate biomass ash-related problems. To investigate the effects of solid waste on the ash fusion characteristics of biomass and its variation mechanisms under an oxidation atmosphere, an X-ray diffraction, thermogravimetric analyzer (TG), scanning electron microscope (SEM), and FactSage calculation were used to examine the ash fusion behaviors of sorghum straw (SS) with the addition of textile dyeing sludge (TDS) or chicken manure (CM). The ash fusion temperature (AFT) of SS increased gradually with the TDS ash addition; with CM ash addition, the AFT of SS mixtures increased rapidly (0–20%), decreased slightly (20–30%), and finally increased slowly (30–60%). The generations of high melting point (MP) minerals (e.g., KAlSi2O6, Fe2O3, and Fe3O4) led to an increase in the AFT of TDS-SS mixtures. The K+ in silicate was gradually replaced by Mg2+ or Ca2+, which caused the generations of high-MP minerals (e.g., Ca3MgSi2O8, Ca2MgSi2O7, and CaMgSiO4). The TG analysis showed that the additions of TDS or CM ash slowed down the weight loss of SS mixed ash due to the formation of high-MP minerals. The SEM and FactSage calculations were also explained with the AFT change and their variation mechanisms. The result provided effective references for the AFT regulation during the co-combustion of biomass and solid waste.

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“…To maintain continuous liquid slagging in industrial gasification operations, the gasifier operating temperature is typically about 100–150 °C above the flow temperature (FT) of the feedstock. For coal with high ash melting temperatures, such as high-silica–aluminum coals, the existence of a large number of refractory materials in ash slag at high temperatures can cause poor ash slag fluidity. − Furthermore, as a result of the complexity and variability of coal types, for some coal with a lower ash melting temperature, although the operating temperature is about 100 °C above the FT, its viscosity is still higher and shows poor fluidity, which makes it difficult to match the liquid slagging requirements of an entrained-flow gasifier. Therefore, in an actual industrial operation process, coal blending or adding flux is commonly adopted to achieve the regulation of coal ash slag fluidity, which is in essence to realize the regulation of coal ash fluidity by altering the ash chemical composition of the feed coal. − Because the transportation cost of coal blending is high and difficult to control, the addition of flux is the optimal scheme to regulate the fluidity of coal ash slag.…”

Section: Introductionmentioning

confidence: 99%

Review and Perspectives of Ash Slag Fluidity during Co-gasification of Industrial Solid Waste and Coal: Characteristics, Chemistry, Controlling Mechanisms, and Regulation

Zhang,

Song,

et al. 2024

Energy Fuels

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The stable fluidity of slag at a high temperature is crucial for the long-period operation of an entrained-flow gasifier. The diversity and difference of coal ash make it difficult to meet the requirements for stable slagging in a gasifier. Consequently, coal blending or adding flux has been employed in the industry to improve the fluidity of coal ash slag. As a carbon-containing matrix, industrial solid waste is a kind of energy substance. Utilizing existing industrial gasifiers to blend combustion of industrial solid waste can not only transform industrial solid waste into fuel but also improve the entrained-flow gasifier slagging performance using the unique ash chemical composition of industrial solid waste. Therefore, sorting out the effect of industrial solid waste on coal ash slag fluidity can not only clarify the regulating mechanism of coal ash slagging but also provide some theoretical support for the large-scale consumption of industrial solid waste. In this review, the effects of acid-and alkali-rich industrial solid wastes and coal co-gasification on coal ash slag fluidity were reviewed from the perspectives of ash melting characteristics and viscosity−temperature characteristics, and the effect mechanism of SiO 2 , Al 2 O 3 , SiO 2 / Al 2 O 3 (S/A), CaO, Fe 2 O 3 , and CaO−Fe 2 O 3 (Ca−Fe) compound fluxes on coal ash slag fluidity were elaborated from the viewpoint of mineral evolution and microstructure. Meanwhile, studies on the ash slag fluidity during the co-gasification of industrial solid waste and coal were prospected, which could afford theoretical guidance for the stable slagging of an entrained-flow gasifier and the resourceful treatment of industrial solid waste.

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Effect of high silicon-aluminum coal ashes on sintering and fusion characteristics of a potassium-rich biomass ash

Cited by 33 publications

References 41 publications

Sequential transformation study of minerals during underground coal gasification: Promising to indirectly reflect the actual reaction condition

Sequential transformation study of minerals during underground coal gasification: Promising to indirectly reflect the actual reaction condition

Regulation Mechanism of Solid Waste on Ash Fusion Characteristics of Sorghum Straw under O2/CO2 Atmosphere

Review and Perspectives of Ash Slag Fluidity during Co-gasification of Industrial Solid Waste and Coal: Characteristics, Chemistry, Controlling Mechanisms, and Regulation

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