Exploration of the Combined Action Mechanism of Desulfurization and Ash Removal in the Process of Coal Desulfurization by Microwave with Peroxyacetic Acid

Tang, Longfei; Wang, Shiwei; He, Huan; Fan, Hongwei

doi:10.1021/acs.energyfuels.7b02112

Cited by 22 publications

(4 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fallavena et al removed 88% of pyritic sulfur in the coal samples using 10% H 2 O 2 with 0.1 mol L −1 HCl. Although the physical or chemical methods are applicable to the removal of inorganic sulfur, they are ineffective for the desulfurization process of coal that contains highly amount of organic sulfur, as finely dispersed and chemical bonding with coal molecules . Therefore, powerful method focusing the removal of organic sulfur has received much attention.…”

Section: Introductionmentioning

confidence: 99%

Transformation of organic sulfur and its functional groups in nantong and laigang coal under microwave irradiation

Zhang

Cai

et al. 2019

J Comput Chem

View full text Add to dashboard Cite

The microwave irradiation experiment of Nantong coal (NTC) and Laigang coal (LGC) has been carried out in a microwave oven and the transformation of organic sulfur and its functional groups was investigated via compact sulfur tester and Fourier transform infrared spectra. The dielectric properties of coal sample are also measured by an Agilent N5244A network analyzer. The result shows that a certain amount of organic sulfur in both NTC and LGC is transformed into iron sulfide, sulfate, and sulfur-containing gas after irradiation of microwave. The retention proportion of the three typical sulfur-containing functional groups in coal is ranking as: disulfide bond (S S) > sulfinyl (S O) > sulfydryl ( SH), and such phenomenon has been explained by the first principle calculation based on the density functional theory. The calculation results of Fukui indices, electrostatic potential, and frontier orbital analysis indicate the reactivity of the S O and S S is lower than that of the SH. The calculated bond dissociation enthalpies and bond dissociation times indicate the chemical bonds of SH and S S need more time to rupture than S O when microwave power is 1000 W.

show abstract

Section: Introductionmentioning

confidence: 99%

Transformation of organic sulfur and its functional groups in nantong and laigang coal under microwave irradiation

Zhang

Cai

et al. 2019

J Comput Chem

View full text Add to dashboard Cite

show abstract

“…However, for the superfine comminution, owing to the mechanochemical effect, the increased specific surface area and developed pore structure adsorb more oxygen from the ambient environment, promoting the formation of an oxidizing atmosphere. For example, CH 3 COOOH can be provided by the oxidation of carboxyl groups, as presented in reaction R6, , while hydroxyl and carboxyl groups may be mainly produced by the oxidation of peroxide or hydroperoxide on the coal particle surface . In addition, the valence bond on the particle surface can be broken and reorganized during the comminution, inducing possible C–S cleavages. …”

Section: Results and Discussionmentioning

confidence: 99%

Chemical Properties of Superfine Pulverized Coal Particles. Part 4. Sulfur Speciation by X-ray Absorption Near-Edge Structure Spectroscopy

et al. 2020

View full text Add to dashboard Cite

Exploring the transformation mechanisms of sulfur during the superfine comminution plays a crucial role in constructing a coal macromolecular model and developing clean coal technologies. In this work, the occurrences of sulfur in raw coal were quantitatively analyzed by X-ray absorption near-edge structure (XANES) and X-ray photoelectron spectroscopy (XPS). The sulfur forms in two typical rank coals were compared, and the influence of particle size on the transformation of sulfur was elucidated. Furthermore, the mechanochemical effect on sulfur speciation during the superfine comminution was focused on. The final results indicate that HN coal contains more thiophene with ring structures, while sulfate is the dominant sulfur form in NMG coal. In addition, pyrite can be easily oxidized to sulfate and elemental S, while sulfide, sulfoxide, and sulfone are susceptible to transformation to thiophene during the coalification. It is worth noticing that during the superfine comminution, the organic sulfur shows a decreasing trend, while the inorganic sulfur shows the opposite, suggesting that a conversion from organic to inorganic sulfur exists due to the mechanochemical effect. In addition, two conversion pathways of sulfur are concluded, i.e., sulfide → sulfoxide → sulfone and thiophene → sulfoxide → sulfone → sulfate, which further elucidate the sulfur transformation mechanisms in coal. As the particle size decreases, there is an evident decline for sulfide and thiophene, while pyrite, elemental S, and sulfate generally increase. As for sulfoxide and sulfone, different tendencies are observed in HN and NMG coals due to the complex oxidation processes. The combined application of XANES and XPS is recommended for better characterization of the sulfur speciation and distribution due to the different probing depths in coal particles. This research provides a comprehensive understanding of the mutual transformation between organic and inorganic sulfur in coal. The elucidation of sulfur migration pathways can further promote the exploitation of more valuable desulfurization methods.

show abstract

“…Microwave irradiation can activate sulfur-containing components in coal and remove sulfur without affecting the coal matrix, [13][14][15] so microwave assistance is widely used in coal desulfurization. Tang et al 16 demonstrated experimentally that microwave-assisted peroxyacetic acid can generate powerful oxidative hydroxyl radicals for oxidative removal of sulfur-containing components. Huang et al 17 selected response surface methodology to investigate the effects of oxidant addition and microwave power.…”

Section: Introductionmentioning

confidence: 99%

Study on the desulfurization effect of coal by microwave–Fenton system

Cheng

et al. 2022

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

BACKGROUND Microwave‐assisted and Fenton reagents were combined to enhance the removal effect of sulfur from coal. The coal samples before and after desulfurization were characterized by various testing methods such as X‐ray photoelectron spectroscopy, X‐ray diffraction and scanning electron microscopy. RESULTS The microwave–Fenton system showed the best desulfurization effect with a desulfurization rate of 77.52% at a microwave power of 800 W and irradiation time of 5 min, which was 82.96% higher than the maximum desulfurization rate of Fenton reagents alone. The desulfurization rates of pyrite sulfur, organic sulfur and sulfate sulfur can reach 88.76%, 58.77% and 59.33%, respectively. CONCLUSION The minerals in the treated coal samples were significantly reduced. The microwave–Fenton system can generate a large number of hydroxyl radicals to break the CS bond, while exposing more sulfur‐containing groups to the reagents, resulting in more oxidation of low‐valent sulfur and sulfoxide to high‐valent sulfone and sulfate sulfur. The model compound removal effect was measured, dibenzyl sulfide > diphenyl sulfoxide > diphenyl sulfoxide > dibenzothiophene, while the microwave–Fenton system could significantly enhance the desulfurization effect of the above four model compounds. It was found that with the increase in applied electric field, the reaction energy barrier decreased and the CS bond was more easily broken, which was favorable to the reaction. © 2022 Society of Chemical Industry (SCI).

show abstract

Exploration of the Combined Action Mechanism of Desulfurization and Ash Removal in the Process of Coal Desulfurization by Microwave with Peroxyacetic Acid

Cited by 22 publications

References 47 publications

Transformation of organic sulfur and its functional groups in nantong and laigang coal under microwave irradiation

Transformation of organic sulfur and its functional groups in nantong and laigang coal under microwave irradiation

Chemical Properties of Superfine Pulverized Coal Particles. Part 4. Sulfur Speciation by X-ray Absorption Near-Edge Structure Spectroscopy

Study on the desulfurization effect of coal by microwave–Fenton system

Contact Info

Product

Resources

About