Hydrogen Production from Rice Straw Gasification over Modified-Limestone Catalyst

Abstract

Malaysian limestone modified with and additions of transition metal promoters (Ni, Fe, and Co) were used for gasification of biomass. The effects of selected metal oxide loading and the addition of sodium carbonate, Na2CO3 as additive and its influence on limestone catalytic activity during gasification for hydrogen conversion were investigated. The catalysts were synthesized through deposition-precipitation (DP) method and characterized by using X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET) surface area, thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). Temperature programmed gasification (TPG) was conducted to investigated the gasification reaction of rice straw and the product gases were analysed using online mass spectrometer. The gasification process was carried out in partial oxygen (5% O2/Helium) environment heating from 50 to 900 °C with mass ratio biomass to catalyst of 2:1. From the results, Ni promoter was found to give the highest H2 conversion followed by Co and Fe. The calcined limestone had shown to act as a catalyst and CO2 sorbent thus enhancing the production of hydrogen. Moreover, additional of Na2CO3 during gasification process had shown a further increment of H2 production.