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A numerical analysis of membrane heat exchanger for heat and water vapor recovery from exhaust gas
Van Cong Le,Thi Nhan Nguyen,Sung Joo Hong(홍성주),Chan Woo Park(박찬우) 대한설비공학회 2022 대한설비공학회 학술발표대회논문집 Vol.2022 No.6
Industrial energy consumption is extremely high. Coal-fired plant units consume a large amount of water and dissipate on the exhaust gas. Recovery energy and water from flue gas is a great concept to solve the energy problem as well as enhance the efficiencies. Herein, a membrane heat exchanger was developed using artificial flue gas to investigate its performance on water vapor and heat recovery. A computational fluid dynamics (CFD) model of membrane condenser was developed based on experimental data to consider the heat and mass transfer behavior. The evaporation-condensation Lee model was used for the condensation of vapor in the gas phase while the porous media model was applied for the mass transport through the membrane. The simulation results were found to have great agreements with experimental results. The temperature contours as well as vapor mass fraction and condensation rate of vapor were investigated to have an insight about the condensation and mass transfer of water vapor.
Alpha-Glucosidase Inhibitory Activity of Saponins Isolated from Vernonia gratiosa Hance
Cong Pham Van,Anh Hoang Le Tuan,Vinh Le Ba,Han Yoo Kyong,Trung Nguyen Quang,Minh Bui Quang,Duc Ngo Viet,Ngoc Tran Minh,Hien Nguyen Thi Thu,Manh Hoang Duc,Lien Le Thi,Lee Ki Yong 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.6
Species belonging to the Vernonia (Asteraceae), the largest genus in the tribe Vernonieae (consisting of about 1,000 species), are widely used in food and medicine. These plants are rich sources of bioactive sesquiterpene lactones and steroid saponins, likely including many as yet undiscovered chemical components. A phytochemical investigation resulted in the separation of three new stigmastane-type steroidal saponins (1 – 3), designated as vernogratiosides A–C, from whole plants of V. gratiosa. Their structures were elucidated based on infrared spectroscopy (IR), one-dimensional (1D) and two-dimensional nuclear magnetic resonance (2D NMR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), and electronic circular dichroism analyses (ECD), as well as chemical reactivity. Molecular docking analysis of representative saponins with αglucosidase inhibitory activity was performed. Additionally, the intended substances were tested for their ability to inhibit α-glucosidase activity in a laboratory setting. The results suggested that stigmastane-type steroidal saponins from V. gratiosa are promising candidate antidiabetic agents.
A numerical analysis of membrane heat exchanger for heat and water vapor recovery from exhaust gas
Van Cong Le,Thi Nhan Nguyen,Sung Joo Hong(홍성주),Chan Woo Park(박찬우) 대한설비공학회 2022 대한설비공학회 학술발표대회논문집 Vol.2022 No.6
Industrial energy consumption is extremely high. Coal-fired plant units consume a large amount of water and dissipate on the exhaust gas. Recovery energy and water from flue gas is a great concept to solve the energy problem as well as enhance the efficiencies. Herein, a membrane heat exchanger was developed using artificial flue gas to investigate its performance on water vapor and heat recovery. A computational fluid dynamics (CFD) model of membrane condenser was developed based on experimental data to consider the heat and mass transfer behavior. The evaporation-condensation Lee model was used for the condensation of vapor in the gas phase while the porous media model was applied for the mass transport through the membrane. The simulation results were found to have great agreements with experimental results. The temperature contours as well as vapor mass fraction and condensation rate of vapor were investigated to have an insight about the condensation and mass transfer of water vapor.
A performance comparison of transport membrane condenser with different membrane shape and material
Van Cong Le(레반콩),Jun Cong Ge(갈준총),Thanh Phuong Nguyen(응웬탄푸옹),Thi Nhan Nguyen(응웬티난),Song Ju Hong(홍성주),Chan Woo Park(박잔우) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
Flue gas from boiler contains a large amount of heat loss and wastewater. Recovery of heat and vapor is highly expected to enhance boiler efficiency and reduce its consumption. Based on the sensible heat and latent heat of vapor in the hot flue gas, membrane condenser can achieve high recover efficiencies by a proper membrane. In this study, the humidity gas was used as artificial flue gas while cooling water contribute to the condensation and transport of vapor. Different membranes were applied when membrane area and operating conditions were kept similar. The performance of plate type and circular type ceramic membrane were compared together. In order to enhance the recovery efficiency of condenser, membrane surface was modified by different methods and materials to obtain the optimal membrane properties. Furthermore, the self-made membrane substrate was developed to compare with the commercially available membrane.