The effect of particle size of CaO and MgO as catalysts for gasification of oil palm empty fruit bunch to produce hydrogen

Finely ground and dried palm oil empty fruit bunch (EFB) was gasified using a temperature-programmed technique which online with mass spectrometer. Temperature-programmed gasification (TPG) was done under 5% oxygen in helium to determine the production of hydrogen, as well as CO, CO2 and CH4. TPG was performed from 50–700 °C at the heating rate of 10 °C min−1. The temperature was held for 1 h at the final temperature. The effect of mass ratio of metal oxide:EFB was also investigated. Different particle size of calcium oxide and magnesium oxide were chosen as the catalysts. Bulk calcium oxide has shown to enhance the evolution of hydrogen. Nanosized calcium oxide enhanced the production of hydrogen compared to the bulk one and consequently reduced the production of carbon dioxide. Interestingly, when the mass ratio of metal oxide:EFB was changed to 1:2, nanosized MgO showed very significant increase of H2 production. All the used catalysts were analyzed by XRD to show the transformation of both bulk and nanosized metal oxides to metal carbonates.

► Dry oil palm empty fruit bunch was gasified to produce H2. ► Bulk and nanosize CaO and MgO catalysts were tested for gasification and CO2 absorbent. ► Nano MgO promotes higher H2 production but a poor CO2 absorbent compared to nano CaO.