Low temperature pyrolysis of lignite in the presence of syngas and combustion characteristics of derived char

Abstract：Lignite pyrolysis under syngas and inert gas at low temperature was conducted in a fixed-bed reactor.The product distribution under different atmospheres and the characteristics of the products including gas composition and the char analyses were investigated in this work.The combustion characteristics of the char obtained at different conditions were also studied and compared.The results show that the oil yield under syngas is higher than that under inert gas by 1.5%-1.9%.The contents of H2S and COS in the gas product during pyrolysis under syngas is higher than that under inert gas,which show that syngas has a better ability in desulphurization of lignite during pyrolysis.Additionally,the oxygen of the char obtained under syngas is lower than that of under inert gas,showing that the syngas beneficial in the de-oxygenating of the lignite.The ignition temperature,peak temperature of maximum weight loss rate and burnout temperature of the chars obtained under the two atmosphere are all a little higher than that of the raw lignite,however,the increment of the three specific temperatures of the chars obtained under syngas are lower than those of under inert gas.CO in syngas can react with water produced during lignite pyrolysis to produce hydrogen with high activity,which can suppress the cross-linking reactions during pyrolysis and enhance the yields of oil and gas.