Thermovolumetric investigations of steam gasification of coals and their chars Stanisław Porada, Grzegorz Czerski, Przemysław Grzywacz, Tadeusz Dziok and Dorota Makowska E3S Web Conf., 14 (2017) 02005 Published online: 15 March 2017 DOI: 10.1051/e3sconf/20171402005