Syngas composition and ash characteristics of corn straw under a CO2 atmosphere

Corn straw is one of the most common materials utilized as biomass. The effects of temperature and residence time on the syngas composition and ash characteristics of corn straw prepared in a CO2 atmosphere in a tubular furnace were studied. The results showed that CO was the dominant component of the syngas. With increasing temperature, the volume fraction of CO first decreased and then increased. When the temperature increased to 800 degrees C, CH4, CnHm and H2 participated in the gas-phase reaction, which promoted the generation of CO. At high temperature, longer residence times before the corn straw reacted completely resulted in greater CO production. Analysis of the ash characteristics showed that the higher the temperature and the longer the residence time were, the lower the ash mass. When the temperature was below 800 degrees C, the inorganic crystals in the residual ash were KCl and SiO2. When the temperature increased to 800 degrees C, the inorganic materials in the ash melted and slagged, resulting in low-melting-point salts such as CaMgSi2O3 and KAlSi3O8. The presence of carbon residue hindered the slagging of ash. At 800 degrees C, ash with a high K content exhibited obvious melting, while ash with a high Al content remained solid. With increasing temperature, the characteristic melting temperatures of ash also increased.