Air Gasification of Malaysia Agricultural Waste in a Fluidized Bed Gasifier: Hydrogen Production Performance

Abstract

Recently, biomass gasification technology to produce hydrogen-rich fuel gas is highly interesting possibilities for biomass utilization as sustainable energy (McKendry, 2002). Hydrogen production from biomass gasification has many advantages as secondary renewable energy source as it is the universe’s most abundant element, clean fuel has the potential to serve as renewable gaseous and liquid fuel for transportation vehicles. As a fuel, hydrogen is considered to be very clean as it releases no carbon or sulfur emissions upon combustion. The energy contained in hydrogen on a mass basis (120 MJ/kg) is much higher than coal (35 MJ/kg), gasoline (47 MJ/kg) and natural gas (49.9 MJ/kg). Additionally, the most important advantage for all the living beings is that when it is burned, hydrogen produces non toxic exhaust emissions. Clearly, the emissions from hydrogen combustion contain no carbon monoxide (CO), carbon dioxide (CO2) and unburned hydrocarbons (Veziroglu et al., 2005). Using biomass as an energy source can reduce the greenhouse gas emission that causes global warming which is a negative effect of using fossil fuels as an energy source. In Malaysia, more than 2 million tonnes of agricultural wastes are produced annually and potentially an attractive feedstock for producing energy as the usage contributes little or no net carbon dioxide to the atmosphere. Major agricultural products are oil palms, sawlogs, paddy and tropical fruits. The palm oil sector is the biggest producer and hence the major contributor to the agricutural residues generation in Malaysia. The oil-palm solid wastes (including shell, fibre and Empty Fruit Bunch (EFB)) are abandoned materials produced during palm oil milling process. For every ton of oil-palm fruit bunch being fed to the palmoil refining process, about 0.07 tons of palm shell, 0.146 tons of palm fiber and 0.2 tons of EFB are produced as the solid wastes. Bagasse which is the matted cellulose fibre residue from sugar cane that has been processed in a sugar mill were produced about 3×105T per year in 1999. Despite the decreasing acreage, coconut still plays an important role in the