Effect of chemical composition of ash on sintering of lignites in circulating fluid bed combustion and successful operation of large CFBC boilers

Selvakumaran, P.; Bakthavatsalam, A.K.

doi:10.1016/j.applthermaleng.2015.03.007

Cited by 17 publications

(1 citation statement)

References 11 publications

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“…During this period, the small particles are transferred by a thermophoresis force to fill the void between the large agglomerates, which accounts for the Figure, the VSR curve first decreases as the temperature increases and the porous structure can be detected in Figure 3h,i. This is because of the evaporation and transition of dissociative water [28]. As the temperature increases, the porous structure is significantly reduced, as shown in Figure 3j,k.…”

Section: Volume Shrinkage Ratio (Vsr) Variations At Various Temperaturesmentioning

confidence: 75%

Effects of SiO2/Al2O3 Ratios on Sintering Characteristics of Synthetic Coal Ash

Zhou

Meng

et al. 2017

Energies

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This article explores the effects of SiO 2 /Al 2 O 3 ratios (S/A) on sintering characteristics and provides guidance for alleviating ash depositions in a large-scale circulation fluidized bed. Five synthetic coal ash (SCA) samples with different S/As were treated in a muffle furnace for 12 h at different temperatures (from 773 K to 1373 K, in 100 K intervals). The morphological and chemical results of the volume shrinkage ratio (VSR), thermal deformation analysis by dilatometer (DIL), scanning electron microscope (SEM), X-ray photoelectron spectrometer (XPS), and X-ray diffraction (XRD) were combined to describe the sintering characteristics of different samples. The results showed that the sintering procedure mainly occurred in the third sintering stage when the temperature was over 1273 K, accompanied with significant decreases in the VSR curve. Excess SiO 2 (S/A = 4.5) resulted in a porous structure while excess Al 2 O 3 (S/A = 0.5) brought out large aggregations. The other three samples (S/A = 1.5, 2.5, 3.5) are made up of an amorphous compacted structure and are composed of low fusion temperature materials (e.g., augite and wadsleysite.). Sintering temperatures first dramatically decrease to a low level and then gradually rise to a high level as S/A increases, suggesting that Al 2 O 3 -enriched additives are more effective than SiO 2 -enriched additives in alleviating depositions.

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Section: Volume Shrinkage Ratio (Vsr) Variations At Various Temperaturesmentioning

confidence: 75%