Inhibition of sodium release from Zhundong coal via the addition of mineral additives: A combination of online multi-point LIBS and offline experimental measurements

Liu, Yingzu; Wang, Zhihua; Lv, Yu; Wan, Kaidi; He, Yong; Xia, Jun; Cen, Kefa

doi:10.1016/j.fuel.2017.10.081

Cited by 30 publications

(9 citation statements)

References 37 publications

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“…Each measurement was repeated three times and the average result is shown along with error bars indicating the statistical uncertainty of the measurements. A three-stage release characteristics of potassium can be clearly observed for the poplar, which is similar to our previous finding on the sodium release characteristics of a burning coal pellet [32,39]: (1) the first narrow peak appears during the devolatilization stage;…”

Section: Potassium Release Characteristics Of Poplar and Corn Strawsupporting

confidence: 89%

“…Table 2 gives the physical and chemical properties of the four additives. All the additives were blended with the biomass at a dosing ratio of 3% by weight, which is a typical dose for sorbents [31,32]. To ensure the additives were well mixed with the biomass, both the additives and biomass were first grounded and sieved to fine powder with a diameter less than 75 μm.…”

Section: Biomass Samples and Mineral Additivesmentioning

confidence: 99%

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Experimental study of potassium release during biomass-pellet combustion and its interaction with inhibitive additives

Liu

Wan

et al. 2020

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In the present study, two types of biomass were investigated as typical agricultural and woody biomass fuel, i.e., corn straw and poplar. Firstly, laser induced breakdown spectroscopy (LIBS) was employed to investigate the release characteristics of potassium (K) from a burning biomass pellet. In order to further investigate the correlation between K release and the combustion process, combustion parameters including pellet surface temperature and pellet diameter were simultaneously measured with LIBS. A dual-peak trend is observed in the K release history of poplar, but only a single peak is found in that of corn straw. Both biomass samples show the strongest K release during the devolatilization stage in comparison with the subsequent char burnout and ash cooking stages. Similar tendencies are observed between K release and pellet temperature, which suggests that K release is closely related to the combustion process. The K release mechanism can be attributed to temperature rise and therefore breakdown of chemical bonds during combustion. Then the release of different chemical forms of K was investigated by chemical fractionation treatment of the biomass samples. 2 The released amount of H2O-soluble, NH4Ac-soluble and HCl-soluble potassium compounds were obtained. The H2O-soluble potassium is found to be the major released potassium compound. Finally, four kinds of additives (two pure additives, i.e., silica and alumina, and two typical natural mineral additives, i.e., kaolin and mica) were added to the biomass samples to investigate their inhibition effects on K release. The natural sorbent additives show better inhibition effects than the pure ones.

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Section: Potassium Release Characteristics Of Poplar and Corn Strawsupporting

confidence: 89%

Section: Biomass Samples and Mineral Additivesmentioning

confidence: 99%

Experimental study of potassium release during biomass-pellet combustion and its interaction with inhibitive additives

Liu

Wan

et al. 2020

Fuel

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“…Since low-grade sub-bituminous coal is well-known to cause adhesion of fly ash and its growth on the surface of super heater, heat exchanger, and furnace walls during the combustion process, it must be cocombusted with high-grade bituminous coal. However, even in such a cocombustion method, these troublesome events tend to occur, inhibiting stable and long-term operation of pulverized coal combustion plants. − …”

Section: Introductionmentioning

confidence: 99%

Toward Stable Operation of Coal Combustion Plants: The Use of Alumina Nanoparticles To Prevent Adhesion of Fly Ash

et al. 2018

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In pulverized coal combustion plants, low-grade sub-bituminous coal is known to cause adhesion of fly ash and its growth on the surface of the super heater, heat exchanger, and furnace walls, even when cocombusted with high-grade bituminous coal. In this study, six different fly ash samples collected from commercial pulverized coal combustion plants were investigated to find if the porosity and the liquid phase would have a significant impact on the tensile strength of the ash powder beds. Herein, we demonstrate that the use of alumina (Al2O3) nanoparticles as an additive is highly effective in preventing such troublesome events, which would be a great aid to facilitate stable and long-term operation of coal combustion plants. The function of Al2O3 nanoparticles is found to be 2-fold: retaining the porosity and perturbing the chemical composition of the ash samples. This is rationally supported by experimental and theoretical results. The key to our study is a split-type tensile strength tester that can directly measure the tensile strength of a powder bed being studied at various temperatures.

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“…Coal, as an important source of primary energy, supports approximately 40% of the worldwide electricity [1,2]. Considering its broad availability and the overall flexibility of coal combustion systems, coal is expected to continually play an important role in the near future [3,4].…”

Section: Introductionmentioning

confidence: 99%

In Situ Measurements of the Release Characteristics and Catalytic Effects of Different Chemical Forms of Sodium during Combustion of Zhundong Coal

et al. 2018

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This work studies the temporal release characteristics of different chemical forms of sodium during the combustion of Zhundong coal and the catalytic effects of sodium on the combustion process via target-sodium removal and enrichment approaches. The target-sodium removal approach extracts specific forms of sodium from the raw coal via a chemical method to produce coal samples with designated characteristics. In the target-sodium enrichment approach, three kinds of H2O-soluble sodium compounds, including NaCl, NaOH and Na2SO4, are manually added into the raw coal. The experimental measurement is conducted using a multi-point Laser-Induced Breakdown Spectroscopy (LIBS) system. The system quantitatively measures the temporal release flux of sodium during the combustion process, and performs the in-situ measurement of surface temperature and diameter of a burning coal pellet. It is found that H2O-soluble sodium is the major chemical form of sodium released during the combustion and exhibits the highest volatility. All the three forms of enriched H2O-soluble sodium compounds show a catalytic effect on the coal combustion (burnout time decreased by more than 5.7%) and the catalytic activity of NaOH is found to be the strongest (burnout time decreased by 36.8%).

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Inhibition of sodium release from Zhundong coal via the addition of mineral additives: A combination of online multi-point LIBS and offline experimental measurements

Cited by 30 publications

References 37 publications

Experimental study of potassium release during biomass-pellet combustion and its interaction with inhibitive additives

Experimental study of potassium release during biomass-pellet combustion and its interaction with inhibitive additives

Toward Stable Operation of Coal Combustion Plants: The Use of Alumina Nanoparticles To Prevent Adhesion of Fly Ash

In Situ Measurements of the Release Characteristics and Catalytic Effects of Different Chemical Forms of Sodium during Combustion of Zhundong Coal

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