Sulcis coal char reactivity under high-pressure H2

The hydrogasification reactivity of charN(2) and charH(2), obtained from Sulcis coal pyrolysis at 900 degrees C in inert and reductive atmospheres, respectively, was investigated in a commercial microreactor under temperature programmed reaction (TPR) at high-temperature (700-800 degrees C) and high-pressure H-2 (1.0-5.0 MPa) conditions. The flue gases were analyzed online by FTIR spectrometry for the identification of volatile species produced. The emissions of carbon (CO2 and CO) coming from both chars reached the maximum releasing rate below 500 degrees C, whereas nitrogen-based compounds (HCNO and NH3) were solely detected during the hydrogasification reaction of charN(2). Meanwhile, the main product of char hydrogasification CH4 was detected at temperature as low as 450 degrees C. Generally, the carbon conversion values of charN(2) were higher than those of charH(2). At low-temperature and pressure reaction conditions the carbon conversion of charH(2) rapidly went down. A first-order reaction rate dependence on H-2 pressure at 800 degrees C was found for charN(2), whereas the reaction order was almost double for charH(2). The apparent activation energies of charN(2)-H-2 reaction at 1.0 and 5.0 MPa pressures were 96 and 78 kJ mol(-1), respectively, whereas the apparent activation energy for charH(2)-H-2 reaction under 5.0 MPa pressure was 140 kJ mol(-1). The Sulcis coal reactivity during the hydrogasification process was significantly impacted by the pyrolysis conditions used in getting chars. (c) 2014 Elsevier B.V. All rights reserved.