Effect of Interaction between Sodium and Oxides of Silicon and Aluminum on the Formation of Fine Particulates during Synthetic Char Combustion

Ruan, Renhui; Xiao, Jiafan; Du, Yongle; Tan, Houzhang; Wang, Xuebin; Yang, Fuxin

doi:10.1021/acs.energyfuels.8b01198

Cited by 11 publications

(10 citation statements)

References 29 publications

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“…It can be seen from Figure a that the ultrafine particles produced by the de-alkali coal are irregular and do not contain crystals. However, there are crystals that significantly formed in the ultrafine particles of the de-alkali coal with Na salts added, which is also reported in ref . Among them, the ultrafine particles of the coal with NaCl added had the highest crystal content, followed by coal with Na 2 SO 4 and NaAc added.…”

Section: Resultssupporting

confidence: 70%

Effects of Alkali Metals on the Formation of Particulate Matter and Adsorption of Floating Beads during Zhundong Coal Combustion

et al. 2019

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Zhundong coal plays an important role in China’s energy utilization. However, due to its high content of alkali metals, it produces a large amount of particulate matter during combustion. In this paper, the coal was first washed with deionized water to remove the influence of alkali-metal salts. Then, different kinds of Na salts (1% NaC1, 1% Na2SO4, and 1% NaAc) were added to the de-alkali coals. The effect of Na salts on the formation of PM10 was studied in a high-temperature drop-tube furnace at 1300 °C. After the addition of the Na salts, the amount of particulate matter emission was significantly increased. When 1% NaCl was added to the de-alkali coal, the amount of PM1 produced was 3.1 times that of the raw coal, while the amount of PM2.5 produced was 3 times that of raw coal. After adding 1% Na2SO4, the amounts of PM1 and PM2.5 produced were twice those of the raw coal. In addition, floating beads exhibit a good adsorption effect on particulate matter for the combustion of the coal with different Na salts added. The yield of ultrafine and submicrometer particles was significantly reduced when 3% floating beads were added to the de-alkali coal with Na salts added. The reductions of PM1 were 47.0% for NaCl, 51.0% for Na2SO4, and 29.4% for NaAc. Additionally, the adsorption process of floating beads on ultrafine and submicrometer particles is mainly through the reaction between alkali-metal vapors and SiO2 and Al2O3 in the sorbents.

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Section: Resultssupporting

confidence: 70%

Effects of Alkali Metals on the Formation of Particulate Matter and Adsorption of Floating Beads during Zhundong Coal Combustion

et al. 2019

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“…Increased Na in ultrafine PM is supposed to be mainly Na 2 SO 4 . Cl has been found to promote Na to participate in sub-micrometer PM . Therefore, the sulfurization of Na could also stabilize the Na species, mitigating the Na capture by Si–Al-dominating particles.…”

Section: Resultsmentioning

confidence: 99%

“…Na has been considered one of the important resources of ultrafine particles from combustion of Zhundong lignite. Its transformation in an early stage of lignite combustion , and interactions with other major minerals , have been widely investigated. However, recent studies found that Mg, Ca, Fe, and S could not be neglected because they may be abundant in fine PM produced from lignite combustion. , Besides, a considerable proportion of Ca and Mg has also been found as ion-exchangeable forms in lignite, such as Victorian brown coal and Zhundong lignite. , They are easy to release during combustion and could contribute more to sub-micrometer PM.…”

Section: Introductionmentioning

confidence: 99%

Characteristic of Particulate Matter from Combustion of Zhundong Lignite: A Comparison between Air and Oxy-fuel Atmospheres

et al. 2019

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The transformation of sodium to particulate matter (PM) during lignite combustion has been widely investigated, while the importance of Ca, Mg, S, and Fe in low-rank coal has been recently revealed. In this study, three kinds of Zhundong lignites (ZD, YH, and HSY) rich in Na, Mg, Ca, S, and Fe were selected and the combustion was conducted in an entrained flow reactor with a furnace temperature of 1473 K. PM was sampled by a Deakti low-pressure impactor (DLPI), and the components were analyzed by scanning electron microscopy equipped with energy-dispersive X-ray spectrometry (SEM–EDS), with the PM number concentration measured by a scanning mobility particle sizer (SMPS). The characteristics of PM under air and oxy-fuel (Oxy21, Oxy30, and Oxy40) atmospheres were compared. The results show that the comparable O2 concentration is related to coal properties and located between 30 and 40% for Zhundong lignite. It is acceptable to take the PM10 mass yield as a reference to reflect the combustion intensity. An oxy-fuel atmosphere has more effect on PM1–10 than PM1. The participation of Na in PM1 is highest under Oxy21 combustion, which is enhanced through S and Cl. An increasing O2 concentration will intensify the fragmentation and decomposition of Ca-, Mg-, Fe-, and Si-bearing minerals, which contribute mostly to the production of PM1–10. The contents of Si–Al-bearing minerals in raw coal significantly affect the contribution of Fe and S on PM1–10 through eutectic formation. Besides, the vaporization of inorganic elements (mostly Ca, Mg, Fe, and Si) will also be enhanced under oxy-fuel combustion at a higher O2 concentration, increasing the PM1 production and moving the number-based particle size distribution (NPSD) toward a larger particle size.

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“…shows that the amounts of water-soluble, ion-exchangeable, acid-soluble, and acid-insoluble Na transferred into PM 10 were 52.1, 19.4, 2.4, and 0.2 µg/g_coal, respectively. This was due to the combined effect of two factors, namely: firstly, the content of Na in the four forms of minerals correspondingly decreased ( Figure 2); secondly, the gasification ability of water-soluble Na (NaCl) was stronger than that of ion-exchangeable Na [26], and the gasification ability of acid-soluble and acid-insoluble Na was inhibited by aluminosilicate and SiO 2 [25]. Figure 8a shows that the contributions of the water-soluble, ion-exchangeable, acid-soluble, and acid-insoluble Fe to PM10 were 2.4%, 37.9%, 33.7%, and 26.0%, respectively.…”

Section: Effect Of Different From Minerals On Element Composition Andmentioning

confidence: 99%

“…The transformation process and results of minerals in different occurrence forms to different mode PM showed significant differences [19][20][21][22]. Water-soluble Na and K, such as their chlorides, are easy to vaporize, and are therefore enriched in ultrafine-mode PM [23,24], while acid-insoluble Na and K, such as Na and K in composite aluminosilicate, can exist stably at high temperatures and mainly become part of coarse-mode particles [25]. Ion-exchangeable Mg, Ca, and Fe are bound to a carbon matrix by chemical bonds, and are easily decomposed and released during combustion [26], thereby significantly contributing to all three modes of PM [21].…”

Section: Introductionmentioning

confidence: 99%

Contribution of Minerals in Different Occurrence Forms to PM10 Emissions during the Combustion of Pulverized Zhundong Coal

Zhao

Gao

et al. 2019

Energies

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The comprehensive and quantitative assessment of the contribution of minerals with different occurrence forms to particulate matter with an aerodynamic diameter of less than 10 μm (PM10) emitted from the combustion of Zhundong coal is of great significance for its clean utilization and for the development of particulate matter formation mechanisms. Samples with simplified occurrence forms of inorganic species were prepared by water-, salt-, and acid-washing of Zhundong coal. The samples were combusted in a drop-tube furnace under 20 vol % oxygen at 1250 °C, and the emitted PM10 was collected. The effects of the minerals in different forms on the PM10 emissions were analyzed by comparing the mass concentration distributions, yields, and elemental compositions of PM10. The results showed that water-soluble, ion-exchangeable, acid-soluble, and acid-insoluble minerals contributed 8.3%, 37.8%, 29.7%, and 24.2% of the PM10 emissions, respectively. The distributions of the Na, Mg, Ca, and Fe contents in PM10 were bimodal, as follows: 63.6% of Na and 54.5% of Fe were deported to the ultrafine mode PM, while 63.6% of Mg and 86.6% of Ca were deported to the coarse mode PM. The distributions of the Si and Al contents were unimodal, namely: 92.9% of Si and 90.5% of Al were deported to the coarse mode PM. Water-soluble Na; ion-exchanged Mg, Ca, and Fe; and acid-insoluble Si and Al played decisive roles in the distribution of minerals in PM10.

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Effect of Interaction between Sodium and Oxides of Silicon and Aluminum on the Formation of Fine Particulates during Synthetic Char Combustion

Cited by 11 publications

References 29 publications

Effects of Alkali Metals on the Formation of Particulate Matter and Adsorption of Floating Beads during Zhundong Coal Combustion

Effects of Alkali Metals on the Formation of Particulate Matter and Adsorption of Floating Beads during Zhundong Coal Combustion

Characteristic of Particulate Matter from Combustion of Zhundong Lignite: A Comparison between Air and Oxy-fuel Atmospheres

Contribution of Minerals in Different Occurrence Forms to PM10 Emissions during the Combustion of Pulverized Zhundong Coal

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