Evolution of Metallurgical Properties and Microstructures of Lump Coal During the Descending Process in COREX Gasifier. Issue 3 (4th March 2021)

• Record Type: Journal Article
• Authors: Xu, Runsheng; Zheng, Heng; Wang, Wei; Schenk, Johannes; Bhattacharyya, Anrin; Xue, Zhengliang; Song, Mingming
• Is Part Of: International journal of coal preparation and utilization. Volume 41:Issue 3(2021)
• Page Start: 216
• Page End: 232
• Publication Date: 2021-03-04
• Subjects: Lump coal -- COREX -- metallurgical properties -- microstructure -- descending process; Coal preparation -- Periodicals; Coal -- Research -- Periodicals; 662.62
• DOI: 10.1080/19392699.2018.1463219
• Languages: English
• ISSNs: 1939-2699

Abstract

ABSTRACT: The operating performance and cost efficient of the COREX ironmaking process strongly depend on the quality of lump coal. In order to investigate the degradation behavior of lump coal in COREX gasifier, the descending process of lump coal was simulated in a high-temperature furnace. The metallurgical properties of lump coal/char at different temperature regions of the gasifier were revealed. The relationship between the microstructures and the metallurgical properties of the lump coal/char was also analyzed. The results showed that the thermal stability was significantly reduced at approximately 300–500°C, and the weakest mechanical strength of char occurred at approximately 600–800°C. With an increase in the annealing temperature, the ordered degree of microcrystalline structures in the char first decreased and then increased, whereas the amount of pores in the char showed the opposite trend. The highly developed pore structure of char at 800°C may be the most important factor leading to its weak mechanical strength. As the temperature increased, the active radicals of coal/char were gradually decomposed, and the anisotropic textures were gradually generated, which contributed to a decrease in the CO2 reactivity during the lump coal descending process.