A novel two-stage gasification strategy for nitrogen-free syngas production- pilot-scale experiments

Abstract : Green waste and wood gasification have been studied through a non-catalytic process. Experiments are conducted at a pilot-scale developed at RAPSODEE Centre to validate the feasibility of producing high-quality nitrogen-free syngas. Biomass is first pyrolyzed at 800 °C in a rotary kiln. Then, the volatile matter is cracked and reformed in a non-catalytic tubular reactor. Effects of temperature and gas residence time in the tubular reactor on the process performances are evaluated. The results show that the tar formed in the first stage for each biomass is mainly converted into soot inside the second one. The soot yield has reached 11.5 wt% at 1300 °C with a gas residence time of 10 s. Wood tar appears to have a different suite of compounds than tar from green waste; they probably have different cracking pathways. The wood tar conversion ratio has achieved 98.8% at 1300 °C with a gas residence of 5 s while it reaches only 80.4% for green waste. Under these operating conditions, the lower heating value of syngas is around 11 MJ/Nm3. The syngas obtained is rich in H2 (up to 50 vol%) and CO (up to 35 vol%) and contains CO2 (<10 vol%) and CH4 (< 5 vol%).