This study presents the effect of particle agglomeration on syngas emission during the biomass air gasification process. Various operating conditions such as operating temperature, equivalence ratio (ER), and amount of bed materials are employed. The concentrations of H-2 and CO increase along with the operating time as agglomeration begins, while CO2 decreases at the same time. However, there is no significant change in the emission concentration of CH4 during the defluidization process. The lower heating value increases while the system reaches the agglomeration/defluidization under various operating parameters. When the system reaches the agglomeration/defluidization process, the LHV value sharply increases. The results are obtained when the system reaches agglomeration/defluidization. The temperature increases while bed agglomeration occurs. A higher temperature increases the production of H-2 and CO, contributing to the LHV calculation. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.