Master of Science in Sustainable Process Development

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Browsing Master of Science in Sustainable Process Development by Author "Gunawardena, SHP"

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    item: Thesis-Abstract
    Effect of ultrasound mixing on esterification of FFA in rubber seed oil
    (2014-08-20) Malliyawadu, MND; Gunawardena, SHP
    There is an increasing demand for biodiesel, because of its environmental friendly nature and especially due to the depletion of petroleum reserves. Currently, most of the biodiesel is produced from edible oils under base catalyzed transesterification. However, large amount of non edible oils are underutilized and can be converted to biodiesel. The difficulty with base catalyzed transesterification of non edible oil is its higher content of free fatty acids. These free fatty acids react with base catalyst to produce soap and which prevent the separation of ester from the glycerin. The reduction of free fatty acid content of rubber seed oil under catalyzed etherification with ultrasonic mixing (20 kHz, 500 W) was investigated in this study and compared with mechanical agitation. Batch etherification of rubber seed oil was carried out using 2.5:1 (w/w) methanol/ FFA and 0.05:1 (w/w) H2S04/FFA and effect of ultrasound frequency, reaction temperature and reaction time were studied. With the increase of ultrasonic amplitude, mixing intensity was increased and as a result, maximum FFA% reduction of 88.9 observed at the amplitude of 75% and at a temperature of 55°C. When the etherification reaction carried out at elevated temperatures, it shows a greater reduction of FFA% under ultrasonic and mechanical mixing. However, optimum result was gained under mechanical mixing at the temperature of 55°C and at a reaction time of 30 min and the final FFA% of rubber seed oil was 2.75. At the same reaction conditions, acid etherification of rubber seed oil under ultrasonic mixing achieved a FFA% of 3.31.
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    item: Thesis-Full-text
    Investigation of temperature profiles of traditional puta and preparation of chalcopyrite ash for ayurvedic treatment using muffle furnace
    Pathiraja, PMYS; Gunawardena, SHP; Herapathdeniya, SKMK
    Bhasmas (ashes) are complex compound forms of metals, minerals or gemstones obtained after a series of ayurvedic pharmaceutical preparation processes; purification (shodhana), trituration (bhavana) and incineration (marana) in combination with various herbal extracts and other substances. These three processes play an important role in preparation of ashes. Puta is the specific quantum of heat required to get the desired quality ashes in the process of incineration (marana) and naturally available fuels like cow dung cakes are used to produce heat in the conventional puta. The amount of heat required to produce a specific ash is substance specific and described in terms of fuel burnt. The objectives of this research are to establish temperature profiles for Maha Puta, Gaja Puta and Varaha Puta and to verify temperature profile of Varaha puta using a muffle furnace. Temperature profiles were established using dried cow dung cakes with an average calorific value of 15.44 MJ/kg as the fuel and the maximum temperatures achieved for Maha Puta, Gaja Puta and Varaha Puta were 1380 0C, 1060 0C and 850 0C respectively. Then temperature profile of traditional Varaha Puta was matched with a muffle furnace and Chalcopyrite ash (Swarna Makshika bhasma) was prepared using both traditional method and electric muffle furnace. The ashes produced using both methods showed similar properties and hence the temperature profile obtained for traditional Varaha Puta using the muffle furnace was verified.