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- Co-gasification of glycerol/fat mixtures in a downflow fixed bed reactor: Preliminary resultsPublication . Almeida, A.; Pilão, Rosa Maria; Ramalho, Elisa; Ribeiro, A.M.; Pinho, CarlosThe aim of this work was to assess the technical viability of glycerol/fat co-gasification. The gasification performance was studied in a downflow fixed bed reactor using steam as oxidizing agent. Tests were performed with a mixture of 10% of fat and 52% of water, and the effect of temperature was evaluated in the 800 ºC to 950 ºC range. Samples of dry gas from the gasifier were collected and analysed by gas chromatography in order to determine the CO, CO2, CH4 and H2 content. The results revealed that the co-gasification of glycerol/fat mixtures seems to be a feasible technical option. Best results of the gasification parameters were obtained at the highest tested temperature, 950 °C.
- Adding Value to Tannery Fleshings Part I – Oils and Protein Hydrolysates – Production and ApplicationPublication . Bragança, I.; Crispim, Alfredo; Sampaio, A.; Ramalho, Elisa; Crispim, F.; Caetano, Nídia; Silva, P. C.The tanning industry generates a high quantity of solid wastes. Therefore, there is a need to create valorization [added value] options for these wastes. The present work had as its main objective creating added value by production of fat and hydrolyzed protein. To this end, fleshings were treated by hydrolysis with regard to the influence of various factors. The best result was found for a temperature of 60°C, 4 hours of hydrolysis, 2% of enzyme and 100% of water, with a fat extraction yield of 93%. The fat obtained through the hydrolysis process was used to produce sulphated oils. The protein hydrolysate was concentrated to about 40% of solids content and used to prepare co-products of protein hydrolysate and glutaraldehyde. Sulphated oils were applied in leather fatliquoring and the different protein hydrolysates were tested in leather retannage. The leather samples obtained were evaluated by physical-mechanical tests and the results were compared to those obtained through a standard process. The results were very satisfactory and, in some cases better than the specified standard. The process of adding value to this waste results in a double advantage for the leather industry, reducing the environmental impact and allowing production of alternative products for leather fatliquoring and retannage.
- Gasification of Cork Wastes in a Fluidized Bed ReactorPublication . Rodrigues, Sara; Almeida, Ana F.; Ribeiro, A.M.; Neto, Paula; Ramalho, Elisa; Pilão, Rosa MariaBiomass 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.
- Valorization of Facts from animal wastes: Biodiesel productionPublication . Sampaio, Alberto; Caetano, Nídia; Ramalho, Elisa; Crispim, Alfredo; Silva, Paula CristinaTwo of the most important concerns regarding planet sustainability are energy management and waste disposal. Renewable energy sources and waste valorization processes are therefore very important. Among biofuels, biodiesel has very good utilization and environmental properties that allow partial or total replacement of diesel fuel. Biodiesel can be produced from residues like waste frying oils and animal fats. The purpose of this work is to produce biodiesel from fat obtained from industrial animal residues: green and lime fleshings from tanneries and slaughterhouses wastes. The fats were previously characterized and some of the samples presented a high acid value. For these materials, an acid esterification step prior to the transesterification reaction was needed, in order to lower the acid value. Transesterification with methanol was performed using sodium hydroxide or sodium methylate as catalysts, at 65ºC. The quality of biodiesel products was assessed by some of EN 14214 Standard parameters. The results show that most of the samples are within the specifications, except for high CFPP. This is typical of biodiesel produced from animal fats that present high saturated fatty acid content. Nevertheless, these products can be used in mixtures with biodiesel from vegetable oils, in order to meet standard specifications
- Gasification of crude glycerol after salt removalPublication . Almeida, Ana; Pilão, Rosa; Ribeiro, A.M.; Ramalho, Elisa; Pinho, CarlosThe 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.