Experimental investigation of producer gas generation on the dual mode of gasification from high‑ash Indian coal

Indian coal with high ash content is a difficult-to-handle fuel in gasification process due to its high ash content that has negative impact on the performance of the reactor, ash handling and overall efficiency of energy conversion in gasification process. The present study investigates the experimental investigation of producer gas production using high‑ash Indian coal in a pilot-scale fixed-bed gasifier with a capacity of 50 kWth which operates in both updraft and downdraft modes in the same reactor. The impact of the different gasification modes and operating time on the producer gas composition, gas yield, reactor temperature, tar formation and cold gas efficiency (CGE) was systematically analyzed. Updraft gasifier exhibited comparatively good gasification performance with higher concentration of H2 (19.37 vol.%) and CO (14.87 vol.%) as compared to the downdraft mode (16.49 vol.% H2 and 11.78 vol.% CO). The producer gas yield and LHV obtained from updraft configuration were 2.30 Nm3 kg−1 and 5.95 MJ Nm−3, respectively, whereas those for the downdraft configuration were 2.25 Nm3 kg−1 and 5.01 MJ Nm−3, respectively. Likewise, maximum cold gas efficiency of the downdraft gasifier has been enhanced to 67.10% for the updraft mode. For the gasification, the maximum temperature of the reactor in the updraft and downdraft was about 750°C and 713°C, respectively. However, the downdraft gasifier generated comparatively clean producer gas because of increased thermal cracking of the volatile compounds, thereby significantly reducing tar formation.