Tar steam reforming during biomass gasification: kinetic model and reaction pathway

In this study, the steam reforming of naphthalene and pyrene as heavy tar model compounds was investigated experimentally in a horizontal tube reactor and theoretically using the CHEMKIN simulation. The experimental results revealed that the reactivity of naphthalene was higher than that of pyrene in the presence of steam. The carbon content converted to soot is a little more than that converted to light gas during tar steam reforming. The kinetic parameters of the overall reaction were determined, and the pre-exponential factor and activation energy were calculated using the experimental data. The comparison of the numerical simulation with the experimental findings exhibited an excellent agreement for the prediction of the light gas products and soot after eliminating the influence of the water–gas shift. Further, the reaction schemes including the reaction pathway and associated kinetics were determined for the steam reforming of these model compounds. Both naphthalene and pyrene exhibited a similar performance during the reaction in the presence of steam. Benzene and naphthalene, representing the precursors of the light gas product, were confirmed to be the dominant intermediate components of naphthalene and pyrene, respectively. The consecutive reactions of these intermediates subsequently resulted in the generation of the light gaseous products. Graphic abstract