Hydrogen-rich gas as a product of two-stage co-gasification of lignite/waste plastics mixtures

•Mixed waste plastics may be co-gasified with lignite to obtain hydrogen-rich gas.•At least 20 wt.% of lignite can be replaced with mixed waste plastics in the process.•Replacing does not have much effect on composition, properties and amount of gas obtained.

Under atmospheric pressure, mixtures of lignite with waste plastics were gasified on a laboratory scale. The resulting tar was cracked in a thermal cracking reactor. For experiments, low-ash and low-sulfur lignite was used; the percentage of waste plastics in the mixtures was 10 and 20 wt.%. The main product of co-gasification was hydrogen-rich gas, as by-products, soot and non-gasified solid residue were obtained. It was found that the higher heating value of obtained gas is fully comparable with that of industrial gas from lignite gasification. Probably, at least 20 wt.% of lignite can be replaced with mixed waste plastics in this process. The effect of waste plastics addition on properties of the obtained gas and of the non-gasified solid residue was evaluated and discussed.