Preliminary assessment of the usefulness of the Polish lignite in the gasification process according to its petrographic composition

The study has been conducted on the lignite samples from 12 currently exploited, perspective and abandoned Polish deposits. Lignite is common in the Polish Lowland and is derived from the Paleogene and Neogene. In order to determine the suitability for gasification based on the petrographic composition, the diagram shown in figure 1 has been used. To be suitable for gasification, the lignite should contain at least 80% of the macerals of the huminite and liptinite groups (H + L mmf) and less than 20% of the macerals of the inertinite group in mineral matter free basis (Immf). The suitability for this process is problematic when the inertinite group content varies between 20 and 50%. Overall, macerals from huminite and liptinite groups within all studied deposits are over 90%. This indicates that the lignite from Polish deposits meet the criterion for petrographic coal for gasification. It should be noted, however, that the problem of petrographic composition of coal for gasification in various types of generators requires further studies.