Abstract: The characteristics of carbon dioxide(CO₂) gasification of sawdust-derived char were studied in high-temperature fixed bed reactor. The effects of temperature and CO₂ flow rate on the volume fraction of gas compositions, low heating value(Q_LHV), gas yield, and solid yield were investigated. The results showed that with the temperature increasing from 750 ℃ to 950 ℃, the volume fraction of CO increased and that of CO₂ reduced, and the Q_LHV of the fuel gas increased obviously, the change trend of Q_LHV was not obvious from 950 ℃ to 1 050 ℃. With the increase of CO₂ flow rate, which was used as the gasification agent, the solid yield reduced, the gas yield increased, and the volume fraction of CO₂ increased obviously, while the volume fraction of CO and Q_LHV increased firstly and then reduced. When the flow rate of CO₂ was 15 mL/(min·g), the Q_LHV was up to the largest. The optimized conditions were the gasification temperature 950 ℃ and CO₂ flow rate 15 mL/(min·g). Under these conditions,the volume fraction of CO was 51.51%, the volume fraction of CO₂ was 37.99%, the Q_LHV was 8.03 MJ/m³, and the gas yield was 0.78 L/g.

Key words: sawdust-derived char, CO₂ gasification, temperature, gas yield, heat value