Magnesite and olivine performance duringcynara Cardunculus L. Gasification: Gas and tar analysis

This work presents a Cynaracardunculus L. air gasification study using a bubbling fluidized bed. Two different bed materials, magnesite and olivine, are tested between 700 and 800ºC with a fixed equivalence ratio of 0.20. Kaolin is added to the biomass in order to reduce agglomeration. Gas and tar composition are obtained by means of μGC, and GC/MS and GC/FID, respectively. A relatively high H₂content for air gasification is obtained (12-16 %v/v with N₂). Total GC detectable tar is very similar for both bed materials whereas tar composition is very different. The benzene, toluene, ethylbenzene and xylene (BTEX) fraction is higher for olivine than for magnesite while the fraction of polyaromatic condensed tars (PAHs) is very similar. Higher catalytic activity at 800ºC is observed for magnesite. Gasification performance (lower heating value, cold gas efficiency, gas yield and, carbon and biomass conversion) is better with magnesite at 700ºC while olivine shows better performance at 800 °C.