Hydrogen Production by High Density Polyethylene Steam Gasification and In-Line Volatile Reforming

Steam gasification (900 °C) of high density polyethylene (HDPE) in a conical spouted bed reactor (CSBR) followed by steam reforming in a fixed bed reactor (Ni commercial catalyst) has been carried out. The effect reforming temperature in the 600–700 °C range has on product yields and gas composition as well as on the amount and nature of the coke deposited on the catalyst has been studied. The reforming leads to a full transformation of C2+ hydrocarbons and tar. The maximum H2 yield is obtained at 700 °C (36 wt % by mass unit of HDPE in the feed, which accounts for 83 wt % of the maximum H2 yield according to stoichiometry), with CH4 conversion being 94% and the coke amount deposited on the Ni catalyst being minimum (3.3 wt % by mass unit of HDPE in the feed). The syngas obtained by reforming at 700 °C has a H2/CO volumetric ratio of 6 and is suitable for hydrogenation reactions and further valorization to produce H2.