Sodium retention behavior of Xinjiang high-alkali coal in a 20 kW slag-tapping combustor test

Hu, Xinglei; Wu, Xiaojiang; Zhang, Zhongxiao; Hu, Fan; Fan, Jie; Chen, Songlin; Lan, Dehui

doi:10.1016/j.fuel.2022.123298

Cited by 10 publications

(4 citation statements)

References 34 publications

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“…The experiment was firstly conducted in a 20-kW slagging-type cyclone fired combustor test facility, which was introduced in Refs. [5,6]. As shown in Figure 2, the test facility is mainly composed of primary air inlet, secondary air inlet, electrical heating cyclone chamber, burn-out chamber with a partition panel inside and a slag tapping hole at the bottom, and other auxiliary equipment.…”

Section: Experimental Conditionsmentioning

confidence: 99%

“…In a recent research, the slagging-type cyclone combustion is also proved to be suitable for the Zhundong coal combustion because of the suppression of the molten slag on sodium diffusion [4]. A following experimental investigation in a slag-tapping combustor studied the sodium retention behavior of Zhundong high-alkali coal, which also shows that the molten slag has a high capacity of capturing alkali metals released during the slag-tapping combustion [5,6]. The release of vapor phase sodium has strong dependence on combustion temperature and coal composition in the slag-tapping combustion.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Investigation of Gaseous Sodium Release in Slag-Tapping Coal-Fired Furnaces by Spontaneous Emission Spectroscopy

Jing

Li³

et al. 2022

Energies

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High-alkali coal is rich in alkali metals, which can cause serious effects such as slagging and corrosion on the heating surface during combustion and utilization. A portable spectral system was utilized to simultaneously measure gaseous Na concentration and temperature in a 20 kW slag-tapping combustor and a slagging boiler furnace of a 300 MW power generation unit by flame spontaneous emission spectroscopy (FES) for simultaneous measuring. The result shows that both ZD-FK and ZD-HSQ (Fukang coal and Hongshaquan coal, Xinjiang Zhundong high-alkali coal) combustion flame temperatures are around 1400 °C at the outlet of the cyclone burner while the latter is slightly higher. The sodium concentration in the gas phase increases with the rising of the initial combustion temperature and unit load for one kind of coal, and the level of sodium concentration has a strong correlation with the Na content for different coal. Most of the sodium in the high temperature zone of the furnace exists in the form of gas phase, and more sodium migrates to fly ash. Combined with the analysis of fly ash and liquid slag samples, a closed-loop analysis of the Na migration path could be established.

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Section: Experimental Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Gaseous Sodium Release in Slag-Tapping Coal-Fired Furnaces by Spontaneous Emission Spectroscopy

Jing

Li³

et al. 2022

Energies

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show abstract

“…Currently, many thermal plants tend to ameliorate the problems by co-firing with coals with lower sodium content, but this further increases the fuel cost for electricity production [29]. Unfortunately, despite of various methods proposed to alleviate the ashfouling and slagging issues such as blending combustion [30], leaching [31] and using additives [32,33], these problems are still far from being completely solved.…”

Section: Introductionmentioning

confidence: 99%

“…Unfortunately, despite of various methods proposed to alleviate the ashfouling and slagging issues such as blending combustion [30], leaching [31] and using additives [32,33], these problems are still far from being completely solved. The keys for eliminating sodium-related ash problems are to inhibit the migration of sodium into its gas phase (flue gas) and to retain more sodium in the ashes, which probably reduces the viscosity of fly ash and raises the ash fusion temperature of ashes in boilers [24,29,34]. To this end, some thermal plants take the measure of adding minerals (e.g., kaoline and montmorillonoid) that are rich in silica and alumina into boilers [35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Co-Firing Zhundong Coal with Its Gangue: Combustion Performance, Sodium Retention and Ash Fusion Behaviors

et al. 2022

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Fouling and slagging are intractable ash-related problems for boilers burning high-sodium coals (HSC) to produce electricity or heat. Reduction and resource utilization of solid waste, coal gangues, is urgent because of stringent environmental regulations and economic benefits. Based on the sodium-rich character of Zhundong coal (ZDC) and the mineralogical features of the coal gangues (ZDG), this work investigated their co-firing performance, the sodium retention behaviors as well as the slagging and fouling tendency of the ashes. Results show that combustion performance of ZDC is not reduced despite ofthe lower reactivity of ZDG. The co-firing reaction follows the 3D diffusion model (cylinder symmetry) which probably reflects the gas diffusion of oxygen to combustible matter. During co-firing, the enriched silica and alumina components in ZDG efficiently react with the alkali and alkaline earth metals (sodium, magnesium and calcium) in ZDC to form complex minerals, thus effectively capturing and retaining sodium. The slagging and fouling propensity of ashes are notably reduced. Overall, co-firing provides an alternative means to solve the ash slagging and fouling issues, and also for the reduction and resource utilization of coal gangues.

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Sodium capture mechanism by simulated silica/aluminosilicate slag at high temperatures

Zhang

et al. 2022

Fuel

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Sodium retention behavior of Xinjiang high-alkali coal in a 20 kW slag-tapping combustor test

Cited by 10 publications

References 34 publications

Experimental Investigation of Gaseous Sodium Release in Slag-Tapping Coal-Fired Furnaces by Spontaneous Emission Spectroscopy

Experimental Investigation of Gaseous Sodium Release in Slag-Tapping Coal-Fired Furnaces by Spontaneous Emission Spectroscopy

Co-Firing Zhundong Coal with Its Gangue: Combustion Performance, Sodium Retention and Ash Fusion Behaviors

Sodium capture mechanism by simulated silica/aluminosilicate slag at high temperatures

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