Steam O2-enriched air gasification of lignite and solid recovered fuel in fluidized bed

Continuous steady-state gasification tests were performed, in which mixtures of lignite and solid recovered fuel (SRF) were fed to a bench-scale facility at atmospheric pressure, loaded with the bottom product of a high-temperature Winkler gasifier as the fluidized bed material. The O-2/fuel and steam/fuel ratios were varied from 0.3 to 0.4 and from 0.25 to 0.35, respectively, and the effects of the temperature were examined at different levels (700, 750, and 800 degrees C). The objective of the experimental campaign was to evaluate the effects of above mentioned operating conditions on the (i) quality of syngas expressed in terms of gas yield (Y-gas), cold gas efficiency (eta(CG)), and carbon conversion (X-C); (ii) effectiveness in tar reduction; and (iii) improvement of the H-2/CO molar ratio. Characterization analyses (grain-size distribution, scanning electron microscopy and energy-dispersive X-ray spectroscopy) were performed on the materials before and after the tests. Pressure-fluctuation signals were acquired during the tests to monitor the fluidization quality and diagnose the correlated incip-ient sintering or agglomeration of the bed particles. At 800 degrees C, the obtained results (Y-gas = 1.53; eta(CG) = 79%; X-C = 92%;tar content = 7.35 g/Nm(3); H-2/CO molar ratio = 0.96) demonstrated the convenient feasibility of gasification with the SRF-lignite mixture as a fuel (SRF/lignite = 0.5 wt/wt) and helped define the operating conditions for future pilot tests aiming for liquid fuel synthesis, although the best results were obtained at 800 degrees C with SFR/lignite = 0.2 wt/wt (Y-gas = 1.79; eta(CG) = 93%; X-C = 102%;tar content = 0.92 g/Nm(3); H-2/CO molar ratio = 0.84).