Abstract: The effect of properties of herb residue and air equivalence ratio on the gasification characteristics of Gangmaoqingre granules was investigated. Experiments were conducted in a pilot-scale dual-loop circulating fluidized bed. With the increase of water content，gasification temperature gradually decreased，the contents of tar and CO2 increased，while CO content and carbon conversion rate decreased. Besides，H2 content，gas calorific value and gasification efficiency increased first and then decreased. Smaller particle size contributed to lower tar content and gas calorific value. However，gas yield，gasification efficiency and carbon conversion increased gradually. With the decrease of particle size，H2，CH4，CO，CnHm contents and gasification temperature increased while CO2 content decreased. With the increase of air equivalence ratio，concentration of combustible gas，especially CO，gas calorific value and tar content gradually decreased. Besides，gasificationtemperature，gas yield and carbon conversion rate gradually increased. But gasification efficiency increased first and then decreased. When water content was smaller than 4%，granularity was smaller than 4mm and air equivalence ratio was between 0.25 and 0.27，gasification efficiency would be higher，gasification result would be better.

Key words: herb residues, dual-loop circulating fluidized bed, gasification, granularity, water content, air equivalence ratio