Characterization of coal char gasification with steam in a micro-fluidized bed reaction analyzer

In this study, the so-called micro-fluidized bed reaction analyzer (MFBRA) was used to characterize the isothermal reaction of char gasification with steam at 0.1 MPa. With minimal inhibition of heat and mass transfer, the article examined the effect of reaction temperature and partial pressure of steam on char gasification behavior and reaction kinetics. It was found that at the experimental temperatures varying in 750-1100 °C, the char-steam gasification reaction can be divided into two regions according to temperatures of 750-950 °C and 950-1100 °C. The reaction was well described by the shrinking core model, and the activation energies of char-steam gasification in such two regions are 166.94 kJ/mol and 79.4 kJ/mol, respectively. The activation energy in the kinetically controlled low-temperature region is very similar to that reported in the literatures, validating the reliability of MFBRA for characterizing char gasification and estimating its kinetics. Furthermore, the reaction order for steam partial pressure was found to be about 0.5 under the tested conditions.