To investigate the release and transformation of fuel potassium during oxygen-steam gasification of biomass, wheat straw is gasified in a fixed-bed reactor system from 400 to 1000 °C. Weight measurement, elemental composition analysis and chemical fractionation analysis are performed. The influence of temperature on the release and transformation of inherent potassium is discussed. The results show that with the increase of gasification temperature, the water-soluble and NH4Ac-soluble K transform into other occurrence modes and the former plays a more important role. During the experiment, slagging is observed at 800 and 1000 °C. Further analysis conforms that the slagging at 1000 °C comprises of potassium silicate. The char obtained from 800 °C gasification is porous and the original fibrous structure of raw sample could be observed.
Keywords Potassium release, transformation, biomass gasification, oxygen-steam