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  • Gasification of Cork Wastes in a Fluidized Bed Reactor
    Publication . Rodrigues, Sara; Almeida, Ana F.; Ribeiro, A.M.; Neto, Paula; Ramalho, Elisa; Pilão, Rosa Maria
    Biomass gasification has been identified as an option for energetic valorisation of organic wastes. This work aimed to study the gasification of cork industry wastes using a semi-batch fluidized bed reactor. The experimental tests were performed using air as oxidizing agent and sand particles as bed material. The heating was performed with an electrical resistance of 3 kW. The effect of biomass load (2–5.6 g), and bed temperature (780–900 °C) on gasification performance was evaluated using an air flow rate of 0.092 g/s. Samples of producer gas were analysed by a gas chromatograph fitted with a thermal conductivity detector. The detected and quantified compounds on producer gas were H2, CO, CH4 and CO2. Temperature and mass load had a predominant role in gasification performance and all gasification parameters increased with the temperature rise. The increase of mass resulted in a decrease of carbon conversion efficiency, cold gas efficiency and dry gas yield. Best results were obtained with mass load at a range of of 2–4 g, working at 850 °C. The results showed that cork particles are a sustainable raw material for gasification processes.
  • Gasification of crude glycerol after salt removal
    Publication . Almeida, Ana; Pilão, Rosa; Ribeiro, A.M.; Ramalho, Elisa; Pinho, Carlos
    The increase in the amount of crude glycerol available on the market, as well as the decrease in its purity due to the use of waste materials in the production of biodiesel, has forced producers to look for alternative ways of valuing this byproduct. In this research work, crude glycerol of a Portuguese biodiesel producer was pretreated using an ion exchange process in order to reduce its salt content. The gasification process was performed using steam as the oxidizing agent in a down-flow fixed-bed reactor using alumina particles as bed material. After the gasification process, the producer gas flowed through a condensing and cleaning system, in order to remove the condensable fraction. Dry gas samples were collected and analyzed by GC in order to quantify the CO, CO2, CH4, and H2 content. Three different feed mixtures were studied with 35%, 39%, and 59% (w/w) water, and the tests were performed at 850, 900, and 950 °C. The results showed that the increase of the water content in the feed mixture led to higher values of H2 and CO2, and lower values for CO and CH4, on the producer gas composition. A slight increase of dry gas yield and hydrogen conversion efficiency with the increase of water content in the feed was observed, while the lower heating value of producer gas decreased. No significant influence of water content was detected in the carbon conversion efficiency and cold gas efficiency. The increase of temperature resulted in the increase of four gasification parameters with maximum mean values of 90% for carbon conversion efficiency, 100% for hydrogen conversion efficiency, 107% for cold gas efficiency, and 1.3 m3/kg raw material. The maximum lower heating value of 14.5 MJ/m3 was obtained at 850 °C.