Agricultural wastes as lignocellulosic biomasses are known as the major resources of bioenergy. These valuable resources can be converted into useful environmental friendly fuels and chemicals. Wheat straw

walnut shell and almond shell are the main agricultural wastes in Kurdistan province

Iran. This study investigates the hydrogen-rich gas production via gasification of these biomasses in supercritical water media. Experiments were performed first

in the base case condition using a stainless steel batch micro reactor system. Then

the effect of reaction time on the total gas yield and yield of hydrogen

were investigated. It was seen that the total gas yields and gasification efficiencies increased by increasing the reaction time to 30 min and then the total gas yield was approximately remained constant. Among three used feed stocks

wheat straw with higher amount of cellulose and lower amount of lignin had the highest total gas and hydrogen yields in shorter reaction times. The maximum hydrogen yields of 7.25

4.1 and 4.63 mmol per gram of wheat straw

almond shell and walnut shell occurred at 10

15 and 20 min of reaction time

respectively.