Effect of catalyst to lignite ratio on the performance of a pilot scale fixed bed gasifier

Abstract

Gasification of lignite in the presence of MgCO3 as a catalyst was carried out in 10 kWe pilot scale (atmospheric pressure) downdraft gasifier. The main disadvantage with lignite is the clinker formation at high temperature. To overcome this problem, MgCO3 lumps were used as a catalyst with lignite. The experiments were carried out with four different catalysts to lignite (C/L) ratios (wt%) viz. 0%, 3%, 5% and 7%. The performance of the gasifier was evaluated on various parameters such as specific fuel consumption (SFC), gas yield, producer gas composition, producer gas heating value (LHV), cold gas efficiency (CGE), tar and particulate matter (PM). The Energy balance, mass balance, and exergy analysis were also carried out for different C/L ratios. The studies reveals with an increase in the C/L ratio, clinker formation reduced and became almost negligent with 7% C/L ratio. Furthermore, the gas yield, H2/CO ratio, LHV, CGE and exergy efficiency also increased by 2.52%, 9.94%, 22.22%, 20.24%, and 29.04%, respectively with the same ratio. Whereas, SFC, tar and PM concentration were reduced by 16.48%, 41.61%, and 33.09%, respectively. The study concludes that the 7% loading of MgCO3 with lignite offered the best results amongst most of the reported feedstock.