The study concerns the distribution of chlorine species in the gaseous phase and the condensed phase during gasification of corn straw. The gasification of corn straw was carried out in a downdraft fixed bed gasifier using air and steam as gasifying agents. The effects of the air equivalence ratio (ER) for corn straw, steam to biomass mass ratio (SB), biomass particle size (PS) and their interactions on the distribution of chlorides were investigated using response surface methodology (RSM). The results indicate that ER and SB have a major effect on the distribution of gaseous chlorides, while ER and PS play the major role in affecting the distribution of chlorine retained in the condensed phase. (C) 2014 Elsevier Ltd. All rights reserved.