Effects of sludge on the ash fusion behaviors of high ash-fusion-temperature coal and its ash viscosity predication

Liu, Xuefei; Zhao, Chaoyue; Yang, Ziqiang; Fan, Hongli; Han, Guopeng; Xu, Mei‐Ling; Wang, Zhiqing; Fang, Yitian

doi:10.1016/j.joei.2023.101254

Cited by 10 publications

(3 citation statements)

References 53 publications

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“…The reaction of Fe 3+ in hematite with aluminosilicate to form the amorphous molten glass phase required a higher reaction temperature compared with iron ions in FeO and Fe 3 O 4 . By comparing the mineral phases in ZC iron‐rich coal ash under different atmospheres and considering previous research, 30,34,35 the main mineral reactions at various temperatures can be summarized as follows:

2 normalF e_{2} O_{3} goodbreak+ CO \to normalF e_{3} O_{4} goodbreak+ FeO goodbreak+ normalC O_{2},

FeO goodbreak+ normalA l_{6} normalS i_{2} O_{13} \to normalF e_{2} Si O_{4} goodbreak+ FeA l_{2} O_{4},

CaO / normalN a_{2} normalO goodbreak+ normalA l_{6} normalS i_{2} O_{13} \to Na ([], AlS i_{3} O_{8}) goodbreak- Ca ([], normalA l_{2} normalS i_{2} O_{8}),

6 FeA l_{2} O_{4} goodbreak+ CaO goodbreak+ 6 FeO \to Ca {(Al, Fe)}_{12} O_{19},

CaSi O_{3} goodbreak+ MgO goodbreak+ Si O_{2} goodbreak+ FeO \to Ca ((),, Mg, Fe) normalS i_{2} O_{6} goodbreak+ O_{2},

…”

Section: Resultsmentioning

confidence: 93%

Ash fusion characteristics of iron‐rich coal in Xinjiang under different atmospheres and the influence mechanism of adding red mud and pipeline scale

Lv,

Wang,

Zhang

et al. 2023

Asia-Pacific J Chem Eng

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To realize the high‐efficiency utilization of iron‐rich coal, it is necessary to conduct in‐depth research on the ash fusion characteristics and regulation mechanism. In this paper, the ash fusion temperature test of iron‐rich coal in Xinjiang (ZC) under different atmospheres was first carried out. Then, red mud (HJ) from Huajin Aluminum Industry and black water pipe scale (GDG) were selected as the additives. After the same ashing procedure, the two additives were mixed with iron‐rich coal ash in different proportions to realize the regulation of the chemical composition of the coal ash to improve the ash fusion characteristic. The ash fusion temperature (AFT) experiment was carried out in the automatic ash melting point analyzer, and high‐temperature ash melting slags at different temperatures were prepared. The mineral phases of coal ash and slag were characterized by XRD and compared with the Factsage simulation calculation results to reveal the influence mechanism of coal ash fusion temperature. The result shows that the fusion temperature of ZC iron‐rich coal ash is significantly different between oxidizing atmosphere and weak reducing atmosphere. Compared with the oxidizing atmosphere, the four characteristic temperatures of ZC iron‐rich coal ash are significantly lower under weak reducing conditions, and the difference is about 150°C. The addition of red mud and pipeline scale increased the fusion temperature of ZC coal ash to varying degrees. The addition of HJ ash has little effect on the deformation temperature of ZC coal ash, while the addition of different proportions of HJ ash significantly increases the flow temperature of ZC coal ash. When the addition ratio of HJ ash is 40%, the flow temperature FT of ZC coal ash increases most obviously, which is about 50°C. The addition of HJ ash and GDG ash will lead to an increase in the content of iron‐containing spinel, thereby increasing the ash flow temperature.

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2 normalF e_{2} O_{3} goodbreak+ CO \to normalF e_{3} O_{4} goodbreak+ FeO goodbreak+ normalC O_{2},

FeO goodbreak+ normalA l_{6} normalS i_{2} O_{13} \to normalF e_{2} Si O_{4} goodbreak+ FeA l_{2} O_{4},

CaO / normalN a_{2} normalO goodbreak+ normalA l_{6} normalS i_{2} O_{13} \to Na ([], AlS i_{3} O_{8}) goodbreak- Ca ([], normalA l_{2} normalS i_{2} O_{8}),

6 FeA l_{2} O_{4} goodbreak+ CaO goodbreak+ 6 FeO \to Ca {(Al, Fe)}_{12} O_{19},

CaSi O_{3} goodbreak+ MgO goodbreak+ Si O_{2} goodbreak+ FeO \to Ca ((),, Mg, Fe) normalS i_{2} O_{6} goodbreak+ O_{2},

…”

Section: Resultsmentioning

confidence: 93%

Ash fusion characteristics of iron‐rich coal in Xinjiang under different atmospheres and the influence mechanism of adding red mud and pipeline scale

Lv,

Wang,

Zhang

et al. 2023

Asia-Pacific J Chem Eng

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“…Due to technical difficulties, few studies have been conducted to experimentally determine the volume fraction of the solid phase in the slag. To simplify the calculations, FactSage calculations can be performed using mass fraction instead of volume fraction to understand the trend of viscosity at different MgO contents [35]. The mass fraction of solids in the mixture is also calculated using the "Equilib" module.…”

Section: Analysis Of the Results Of Direct Alloyingmentioning

confidence: 99%

The Direct Alloying of Steel through Silicothermic Self-Reduction of Chromite Ore Utilizing Si-Containing Solid Waste

Chen,

Xue,

Song

2024

Metals

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Organosilicon materials generate copious amounts of Si-containing solid waste during production, leading to severe environmental pollution and substantial resource squandering. In pursuit of the resource utilization of Si-containing solid waste, this study conducted experimental research on the direct alloying of molten steel through the silicothermic self-reduction of chromite ore using Si-containing solid waste as a reducing agent. Additionally, thermodynamic analysis was performed, employing the thermodynamic calculation software FactSage 8.2 (Thermfact Ltd., Montreal, QC, Canada and GTT-Technologies, Aachen, Germany), to examine the equilibrium reactions of the silicothermic reduction of chromite ore and the variations in the thermodynamic equilibrium compositions of slag and metal phases. The results indicate a reduction sequence for the reducible components in chromite ore as Fe2O3 → Cr2O3. The introduction of CaO and Al2O3 into the silicothermic self-reduction compacts altered the forms of Fe and Cr oxides in equilibrium, significantly reducing the standard Gibbs free energy (ΔG0) of the silicothermic reduction reaction. The initial slag melting point decreased from 1700 °C without the addition of CaO and Al2O3 to 1500 °C with the addition of CaO and Al2O3. Correspondingly, the slag viscosity at 1600 °C decreased from 134.1 Pa·s without CaO and Al2O3 addition to 1.81 Pa·s with CaO and Al2O3 addition. The addition of CaO and Al2O3 accelerated the reduction of Cr oxide in chromite ore and enhanced the recovery of Cr, consistent with the thermodynamic calculation results. In the process of steelmaking through the direct alloying of chromite ore silicothermic self-reduction compacts, the final recovery rate of Cr increased from 86.4% without CaO and Al2O3 addition to 95.4% with CaO and Al2O3 addition.

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“…Ash chemical composition plays a decisive role in coal ash melting characteristics. − To simplify the coal ash system, the coal ash chemical composition is described as different oxides and can be divided into two categories, acidic oxides (SiO 2 , Al 2 O 3 , and TiO 2 ) and alkaline oxides (CaO, Fe 2 O 3 , Na 2 O, MgO, and K 2 O), on the basis of the difference in oxide ionic potential. Vorres et al considered that the behavior of different oxides in coal ash was related to the ion chemical structure, and the conception of “ion potential” was put forward, i.e., the ratio of the valence of ions to their radius .…”

Section: Liquid-slagging Process In An Entrained-flow Gasifiermentioning

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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Effects of sludge on the ash fusion behaviors of high ash-fusion-temperature coal and its ash viscosity predication

Cited by 10 publications

References 53 publications

Ash fusion characteristics of iron‐rich coal in Xinjiang under different atmospheres and the influence mechanism of adding red mud and pipeline scale

Ash fusion characteristics of iron‐rich coal in Xinjiang under different atmospheres and the influence mechanism of adding red mud and pipeline scale

The Direct Alloying of Steel through Silicothermic Self-Reduction of Chromite Ore Utilizing Si-Containing Solid Waste

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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