Coking coal is geologically scarce resource and most of them cannot be directly used in steel making due to their higher sulfur content. One desulfurization method that has great potential for massive application is microwave desulfurization, which removes the relatively stubborn organic sulfur under mild conditions. The dielectric properties of coals determine the efficiency of the microwave energy absorption. The key to describing the mechanism of microwave desulfurization and further improvement of the desulfurization efficiency is the dielectric response of organic sulfur compounds in coal to microwave. This study focuses on existing formand microwave response of organic sulfur components of three typical coking coal in China. Resultsshowed that the major organic sulfur in selected coals is thiophene which has a stable structure and is the most difficult to be removed. Several dielectric peaks (dielectric loss)andsignificant differencesofeach selected coal samples are observed. The microwave absorption peaks of the model sulfur compounds are identified to be within 9-11GHz. The real parts of the relative dielectric constants (hereinafter referred to as ε ′) shows a decreasing trend as: diphenyl sulfoxide > diphenyl sulfone > diphenyl sulfide > dibenzothiophene > Octadecane thiol. Response to microwaveare observed to be distinctively different between sulfur-containing and sulfur-free model compounds. The dielectric polarization of mixture (coal mixed with model sulfur compounds) is greater than pure coal. Meanwhile the higher the sulfur content of the coal, the greater the ε ′ is. Sulfur componentsin coal can significantly influence its polarization.
Understanding the structural characteristics of high-sulfur coking coals is essential for the effective use of high-sulfur coals. In this study, thermal dissolution was employed to separate the Duizhen high-sulfur coking coal (DZ) into an extract (DZE) and a residue (DZR). The influence of the structural differences between DZE and DZR on sulfur migration behavior was further investigated, and the quality of the cokes from co-pyrolysis of DZ with DZE and DZR was evaluated. The results indicate that DZE is rich in aliphatic chain structures and oxygen-containing functional groups, whereas DZR retains a higher content of aromatic matrix and ash. DZE promotes the migration and transformation of sulfoxides and thiophenes by releasing reactive H and enhancing mass transfer. In contrast, the highly aromatic structure of DZR tends to bind with reactive sulfur species, forming stable sulfur-containing compounds, which thereby inhibits the release of H 2 S. Functioning as both a hydrogen donor and a binder modifier, DZE not only enhances synergistic desulfurization during co-pyrolysis but also contributes to improved coke quality. Although DZF also supports desulfurization to some extent, its limited caking properties and elevated ash content adversely affect the structural integrity and overall quality of the resulting coke. This study further explored the synergistic effects occurring during the co-pyrolysis process, revealing how the distinct structural features of the separated fractions influence sulfur migration behavior. This study provides theoretical basis and technical pathways for the clean and efficient conversion and resource utilization of high-sulfur coal.
危险品化学品经营许可证（带存储）