Yazar "Un, Umran Tezcan" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Lipid extraction from microalgae Chlorella and Synechocystis sp. using glass microparticles as disruption enhancer
    (Sage Publications Ltd, 2019) Derakhshandeh, Masoud; Atici, Tahir; Un, Umran Tezcan
    In this study, the effect of adding microparticles of glass as a cell disruption enhancer to maximize the extracted lipid from wild-type microalgae Synechocystis and Chlorella sp. has been investigated. A general factorial design approach at different levels has been implemented to evaluate the effectiveness of size and quantity of glass particles for both species. The statistical analysis of variance for the obtained results revealed the significance of the method and defined factors. The recorded extraction efficiency of lipid without addition of particles was 45.02 and 23.19% for Synechocystis and Chlorella sp., respectively. With the addition of particles, the highest recorded value for Chlorella was 34.01% which stands for 46.60% enhancement of extraction efficiency. This was achieved when 40 mu m particles in 2.25 mass proportion of particle to dried biomass were used. The addition of particle did not improve the lipid extraction efficiency for the Synechocystis sp. These findings also showed that the conventional gravimetric methods may underestimate the lipid content of microalgae species.
  • Küçük Resim Yok
    Öğe
    Optimization of carbon dioxide absorption in a continuous bubble column reactor using response surface methodology
    (Wiley, 2023) Gul, Ayse; Derakhshandeh, Masoud; Un, Umran Tezcan
    Carbon dioxide absorption using amine based solvents is a well-known approach for carbon dioxide removal. Especially with the increasing concerns about greenhouse gas emissions, there is a need for an optimization approach capable of multifactor calibration and prediction of interactions. Since conventional methods based on empirical relations are not efficiently applicable, this study investigates use of Response Surface Methodology as a strong optimization tool. A bubble column reactor was used and the effect of solvent concentration (10.0, 20.0 and 30.0 vol%), flow rate (4.0, 5.0 and 6.0 L min-1), diffuser pore size (0.5, 1.0 and 1.5 mm) and temperature (20.0, 25.0 and 30.0 degrees C) on the absorption capacity and also overall mass transfer coefficient was evaluated. The optimization results for maintaining maximum capacity and overall mass transfer coefficient revealed that different optimization targets led to different tuned operational factors. Overall mass transfer coefficient decreased to 34.7 min-1 when the maximum capacity was the desired target. High reaction rate along with the highest absorption capacity was set as desirable two factor target in this application. As a result, a third scenario was designed to maximize both mass transfer coefficient and absorption capacity simultaneously. The optimized condition was achieved when a gas flow rate of 5.9 L min-1, MEA solution of 29.6 vol%, diffuser pore size of 0.5 mm and temperature of 20.6 degrees C was adjusted. At this condition, mass transfer coefficient reached a maximum of 38.4 min-1, with a forecasted achievable absorption capacity of 120.5 g CO2 per kg MEA.