Influences of Ash-Existing Environments and Coal Structures on CO2 Gasification Characteristics of Tri-High Coal

Abstract

Two kinds of tri-high coals were selected to determine the influences of ash-existing environments and coal structures on CO2 gasification characteristics. The TGA results showed that the gasification of ash-free coal (AFC) chars was more efficient than that of corresponding raw coal (RC) chars. To uncover the reasons, the structures of RCs and AFCs, and their char samples prepared at elevated temperatures were investigated with SEM, BET, XRD, Raman and FTIR. The BET, SEM and XRD results showed that the Ash/mineral matter is associated with coal, carbon forms the main structural framework and mineral matters are found embedded in the coal structure in the low-rank tri-high coal. The Raman and FTIR results show that the ash can hinder volatile matters from exposing to the coal particles. Those results indicate that the surface of AFC chars has more free active carbon sites than raw coal chars, which are favorable for mass transfer between C and CO2, thereby improving reactivity of the AFC chars. However, the gasification reactivity was dominated by pore structure at elevated gasification temperatures, even though the microcrystalline structure, functional group structure, and increase in the disorder carbon were improved by acid pickling.

The Correlation between the Structure Characteristics and Gasification Characteristics of Tar Residue from Pyrolysis

“…In addition, the technology and process involved in the study of thermal decomposition and the subsequent gasification of tar slag also provide a basis for the treatment of other energy-containing solid wastes in the metallurgical industry, promoting sustainable utilization modes of energy and resources. Gasification characteristics are influenced by factors such as pore structure and carbon structure [12]. Wang et al [13] analyzed the CO 2 gasification properties of three biomass chars and anthracite chars by the thermogravimetric analysis method and concluded that the gasification properties of the chars were determined by the carbon structure.…”

Gas, Water and Solid Waste Treatment Technology

“…The ZnO materials were applied for adsorption of phosphate from water using batch experiments. The effects of pH (4)(5)(6)(7)(8)(9)(10), adsorption time (30-240 min), the amount of adsorbent (0.1-0.7 g/L) and initial concentration of phosphate (147.637-466.209 mg/L) on the adsorption efficiency were investigated. The optimal condition was found at pH = 5 and at an adsorption time of 150 min.…”

“…Liu et al [6] reported that two kinds of tri-high coals were selected to determine the influences of ash-existing environments and coal structures on CO 2 gasification characteristics. The TGA results showed that the gasification of ash-free coal (AFC) chars was more efficient than that of corresponding raw coal (RC) chars.…”