Steam gasification of Greek lignite and its chars by co-feeding CO2 toward syngas production with an adjustable H2/CO ratioSteam gasification of Greek lignite and its chars by co-feeding CO2 toward syngas production with an adjustable H2/CO ratio Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2022-10-212021enThis research has been co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH - CREATE - INNOVATE (project code: T1EDK-01894). Low-rank lignite is among the most abundant and cheap fossil fuels, linked, however, to serious environmental implications when employed as feedstock in conventional thermoelectric power plants. Hence, toward a low-carbon energy transition, the role of coal in world's energy mix should be reconsidered. In this regard, coal gasification for synthesis gas generation and consequently through its upgrade to a variety of value-added chemicals and fuels constitutes a promising alternative. Herein, we thoroughly explored for a first time the steam gasification reactivity of Greek Lignite (LG) and its derived chars obtained by raw LG thermal treatment at 300, 500 and 800 °C. Moreover, the impact of CO2 addition on H2O gasifying agent mixtures was also investigated. Both the pristine and char samples were fully characterized by various physicochemical techniques to gain insight into possible structure-gasification relationships. The highest syngas yield was obtained for chars derived after LG thermal treatment at 800 °C, due mainly to their high content in fixed carbon, improved textural properties and high alkali index. Steam gasification of lignite and char samples led to H2-rich syngas mixtures with a H2/CO ratio of approximately 3.8. However, upon co-feeding CO2 and H2O, the H2/CO ratio can be suitably adjusted for several potential downstream processes.http://creativecommons.org/licenses/by/4.0/International Journal of Hydrogen Energy465628486-28500 Lampropoulos Athanasios Binas Vassilios Konsolakis Michail Κονσολακης Μιχαηλ Marnellos George E. Elsevier Greek lignite Lignite chars Torrefaction Slow pyrolysis Combined steam and dry Gasification Syngas production