The effect of strengthening thermal fragmentation by rotary kiln on sulfur distribution of fragmentation char with low-rank coal. (1st September 2022)

• Record Type: Journal Article
• Authors: Yang, Yanbo; Chu, Mo; Gao, Min; Jia, Chenxin; Zhou, Lingmei; Chang, Zhibing
• Is Part Of: Fuel. Volume 323(2022)
• Publication Date: 2022-09-01
• Subjects: Thermal fragmentation -- Sulfur distribution -- Coalification degree -- Plastic layer -- Conjoined structure -- Morphological sulfur; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2022.124444
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Plastic layer hindered the effect of desulfurization by thermal fragmentation. Destruction of conjoined structure reduced the sulfur content of the large-size char. Thermo-mechanical action inhibited adhesion of the fine particles with high-sulfur. Thermo-mechanical action promoted the fragmentation of sulfones into small-size char. Abstract: Thermal fragmentation of low-rank coal was generally viewed as a negative effect. Actually, the thermal fragmentation had a positive effect on the pyrolysis desulfurization of low-rank coals, and it is expected to be a new way to realize the desulfurization of large-size char. A fixed bed pyrolysis device and rotary kiln pyrolysis device were used to investigate the effect of pure thermal action and thermo-mechanical action on the sulfur distribution in thermal fragmentation char of lignite and sub-bituminous coal at 300–900 °C. The intervention mechanism of thermo-mechanical strengthen thermal fragmentation on low-rank coal with different coalification degrees was obtained. For lignite, the non-sulfur components were more fragmented than the high-sulfur components due to thermo-mechanical action at the low-temperature stage. Fragmentation of high sulfur components dominated thermal fragmentation at the high-temperature stage. For sub-bituminous coal, conjoined structures and plastic layer hindered the fragmentation of sulfur-containing components by pure thermal action. The thermo-mechanical action under rotary kiln pyrolysis was helpful for the fragmentation of the conjoined structure and the separation of the char and plastic layer, thereby reducing the Fe-S minerals and organic sulfur content of the large-size char. The difference in organic sulfur caused by thermo-mechanical action is mainly due to the fragmentation of sulfone components.