You have no items in your shopping cart.
ABSTRACT The reactivity of Coal Char is dependent on both the physical and chemical changes that take place during the treatment of the coal particles. Few studies on char from Nigeria coal are reported in the open literature. This study focuses on the characterization of two Nigerian bituminous coals and the distribution of their pyrogenic poly aromatic hydrocarbons (PAH) during their conversion to char. The chemical and physical behavior, reactivity and activation energies of the Coal Char were also investigated. The coals were subjected to thermogravimetric analysis (TGA) under predetermined isothermal condition (≤75 μm particle size, at a heating rate of 10 oC/min to 370, 385, 400 and 415 oC respectively under atmospheric pressure). The char properties were examined as function of temperature to determine their chemical, petrographics and physical properties using Fourier Transform Infra-Red Spectroscopy (FTIR-ATR), Scan Electron Microscopy (SEM), small angle X-ray scattering (SAXS), High Resolution Thermal Electron Microscopy (HRTEM) and Micromeritics ASAP 2010 Analyser for BET surface area. The data obtained from the TGA were numerically fitted to a fourth order polynomial from where the activation energies were determined by a single step regression analysis. Data generated from the HRTEM were analysed and interpreted using Material Studio (6.0) to address the environmental concerns due to the release of pollutants during coal utilization processes. The results indicate that the coals were confirmed to be medium rock C bituminous. The mean total reflectance of the BMT coal at the range of 4500C to 7000C was in the range of 1.74 to 4.73 percent. The values of 1.41 to 4.82 percent were obtained for the AFZ coal. The fuel ratios were determined to be in the range 5.4 to 24.1, 5.9 to 24.4 for the MBT and AFZ coals respectively. The chemical properties converged to the same value at the final temperature of 7000C. A correlation was established between the total reflectance and aromaticity. The defined relationship confirmed that the total reflectance may be used as a measuring index in coal analysis. The mean activation energies of the chars were 142 [kJ/mol] for the AFZ coal and 104 [kJ/mol] for the MBT coal. The major poly aromatic hydrocarbons (PAH) present in the coals were Naphthalene and Anthracene. This study has provided a detailed evaluation of the transition of two Nigerian bituminous coals to char.
