A mathematical model is proposed for flowsheet development for hydrogen production from empty fruit bunch from oil palm via steam gasification with in-situ CO 2 capture using CaO as sorbent. The flowsheet model incorporates the chemical reaction kinetics, and mass and energy balances calculations. At 1150 K, > 70 mole hydrogen can be produced. CO2 are fully absorbed from the system at sorbent/biomass ratio of 2:1. The thermodynamic efficiency of the gasifier increases with temperature reaching a maximum efficiency of 84 at steam/biomass ratio of 2:1. Using CaO as the sorbent in the gasifier, the efficiency can be increased by 10 compared to the conventional gasification method. This is an abstract of a paper presented at the 19th International Congress of Chemical and Process Engineering and 7th European Congress of Chemical Engineering (Prague, Czech Republic 8/28/2010-9/1/2010).