Release and transformation of sodium during combustion of Zhundong coals

Li, Guangyu; Wang, Chang‐An; Yan, Yu; Xi, Jin; Liu, Yinhe; Che, Defu

doi:10.1016/j.joei.2015.01.011

Cited by 168 publications

(98 citation statements)

References 37 publications

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“…When the temperature was up to 800 • C, the Na released mainly as NaCl vapor [39]. The Na in the form of AC salts increased slightly with temperature, which is consistent with the research of Li, Zhang, and Song [34,40,41]. In addition to the Water-Soluble, Ammonium acetate-Soluble, and Hydrochloric acid-Soluble forms, an organic form also existed for Na in the fly ash.…”

Section: Influence Of Temperature On the Occurrence Form Of The Alkalsupporting

confidence: 77%

The Effect of Rice Straw Gasification Temperature on the Release and Occurrence Modes of Na and K in a Fluidized Bed

2017

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Rice straw gasification was carried out in a laboratory fluidized bed reactor system from 600 to 800 • C in order to well-understand the release and occurrence mode of alkali metals as a function of temperature during the gasification process. Inductively coupled plasma atomic emission spectrometry (ICP-AES) was applied to analyze the original rice straw and obtained fly ash at different temperatures. The results show that the Water-Soluble, Ammonium acetate-Soluble, Hydrochloric acid-Soluble, and Aluminosilicate Combination-Soluble modes of the Na and K contents in rice straw decreased in sequence. The content of Water-Soluble salts of Na and K accounts for more than 50%, while the content of the Aluminosilicate Combination-Soluble mode is the lowest: less than 5%. The release rate of Na appears to be consistent but nonlinear, increasing with gasification conversion ranges between 50.2% and 70.8%, from which we can deduce that temperature is not the only factor that impacts Na emission. The release of K can be divided into two stages at 700 • C. At the first stage, the release rate of K is almost invariable, ranging from 23.3% to 26%. At the second stage, the release rate increases sharply: up to 55.9%. The concentration and the proportion of the Water-Soluble, Ammonium acetate-Soluble, and Hydrochloric acid-Soluble modes of Na in fly ash decrease with a temperature increase. The release of K can be explained as follows: one path is an organic form of K converted into its gaseous phase; the other path is a soluble inorganic form of K that is volatile at a high temperature. With a temperature increase, the Aluminosilicate Combination-Soluble mode of both Na and K increases.

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Section: Influence Of Temperature On the Occurrence Form Of The Alkalsupporting

confidence: 77%

The Effect of Rice Straw Gasification Temperature on the Release and Occurrence Modes of Na and K in a Fluidized Bed

2017

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“…However, due to the insufficient understanding of its characteristics, the utilization of Zhundong coal is limited by the occurrence of severe slagging and fouling [2,3]. To better understand and resolve these two problems, researchers have tested Zhundong coal extensively, but mostly in laboratory-scale furnaces [2,[4][5][6][7][8]. The main cause for slagging and fouling of Zhundong coal is attributed to the richness of alkali-alkaline earth metal (AAEM) elements, particularly Na.…”

Section: Introductionmentioning

confidence: 99%

“…[2][3][4]8]. Na in the coal may also be involved in complex transformation reactions and partially ends up in the form of silicates and sulfates.…”

Section: Introductionmentioning

confidence: 99%

“…The Na vapors will nucleate/condense to form sticky fine particles, thus accelerating the ash deposition in the boilers [2,4]. In Zijing bituminous coal, a type of Zhundong coal containing 12.77 wt% Na 2 O in coal ash, volatilized Na content was maintained at 20-55 wt% during combustion at 400-1000°C, in which Na volatilization was kept at a high level within 600-900°C [8]. Volatilized Na will adhere, through sulfation [10] or condensation, to the heated surfaces and other ash particles to form a sticky inner layer on the bare heating surfaces or to form a sticky coating surface of bulk ash particles, which are considered as two necessary aspects of ash deposition [4].…”

Section: Introductionmentioning

confidence: 99%

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Effects of wall temperature on slagging and ash deposition of Zhundong coal during circulating fluidized bed gasification

Song

et al. 2016

Applied Thermal Engineering

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“…Xuzhou (Ge et al, 2015a) Datong (Yang et al, 2015) Shenhua Shenhua (Ge et al, 2015b) Shenmu (Li et al, 2016) Proximate analysis (%) Moisture …”

Section: Hhv Ad Of Coals Vs Rq Mmentioning

confidence: 99%

Modified respiratory quotient to evaluate the environmental impact of Chinese coal combustion

Chen

Lei

Shen

et al. 2018

IJOGCT

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Considering the effect of ash and moisture on CO 2 emission during combustion, a modified respiratory quotient (RQ m ) was employed to determine the CO 2 emission potential of anthracite, bituminous, lignite, and peat in China. It was found that the conventional RQ of different Chinese coals was almost the same (from 0.9 to 1), but RQ m of coals varies significantly. The low-rank coals such as peat and lignite have significantly high RQ m which can go up to 7. The high-rank coals such as anthracite and bituminous coals have RQ m between 1 and 2. Higher RQ m means more CO 2 emission since more energy is required to transport or process the low-rank coals. Moreover, correlations between O/C and H/C ratios of the coals and RQ m were also analysed. It was found that low-rank coals such as lignite and peat have higher H/C and O/C ratios and their RQ m are correspondingly higher. [Received: April 2, 2017; Accepted: July 1, 2017] Keywords: respiratory quotient; carbon dioxide; heating value; zero emission; coal.Reference to this paper should be made as follows: Chen, W., Lei, Y., Shen, S., Sun, J., Thanapal, S. and Fan, X. (2018)

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Release and transformation of sodium during combustion of Zhundong coals

Cited by 168 publications

References 37 publications

The Effect of Rice Straw Gasification Temperature on the Release and Occurrence Modes of Na and K in a Fluidized Bed

The Effect of Rice Straw Gasification Temperature on the Release and Occurrence Modes of Na and K in a Fluidized Bed

Effects of wall temperature on slagging and ash deposition of Zhundong coal during circulating fluidized bed gasification

Modified respiratory quotient to evaluate the environmental impact of Chinese coal combustion

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