Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Gıda Mühendisliği Bölümü, Türkiye
Tezin Onay Tarihi: 2011
Öğrenci: ÖZGEN YALÇIN
Eş Danışman: GÜRKAN KARAKAŞ, HALUK HAMAMCI
Özet:The esterification of lactic acid with ethanol over Lewatit S 100, strong cation ion exchange resin catalyst, was studied in counter current vapor-liquid contactor type differential reactor by feeding ethanol and lactic acid solution as vapor and liquid phases, respectively. The ethanol vapor phase was diluted by dry air and the water removal was achieved by the mass transfer of water from liquid to vapor phase. Effect of ethanol to lactic acid feed molar ratio and vapor flow rate on fractional conversion and water removal efficiency were tested at 40-70°C of column temperature range. It was observed that Lewatit S 100 was adequate catalyst for esterification of lactic acid with ethanol. Increase in ethanol to lactic acid feed molar ratio enhanced both lactic acid conversion and water removal by upper product stream. However, lactic acid conversion was suppressed by the increase of inlet vapor flow rate because of the decrease in ethanol concentration in gas phase which affected both esterification reaction rate and mass transfer rate. The reaction temperature is the other important parameter that affects the mass transfer of ethanol from vapor to liquid phase. Although reaction rate and equilibrium conversion values were promoted by temperature, the lower solubility of ethanol in liquid phase limited the fractional conversion while promoted the water mass transfer from liquid to vapor phase. The optimized vapor phase velocity and temperature can yield higher conversions than the equilibrium conversion at the same temperature and initial composition. Therefore, low pressure organic acids such as lactic acid can be successfully esterified by using counter current V-L contactor type reactors and by using integrated reaction and separation units.