Modeling of SO2 seawater scrubbing in countercurrent packed-bed columns with high performance packings

2019 ◽  
Vol 226 ◽  
pp. 162-180 ◽  
Author(s):  
Ion Iliuta ◽  
Maria C. Iliuta
Author(s):  
Qabul Dinanta Utama ◽  
Azis Boing Sitanggang ◽  
Dede Robiatul Adawiyah ◽  
Purwiyatno Hariyadi

Lipase-catalyzed transesterification between refined bleached deodorized palm olein (RBDO) and tricaprylin to produce medium-long-medium structured lipid (MLM-SL) in a packed bed reactor (PBR) has been investigated. A specific sn-1,3 commercial Lipozyme TL IM was used as biocatalyst.  Within this study, the progress of transesterification was monitored especially for triacylglycerol (TAG) formation with equivalent carbon number (ECN) of 32, presumably 1,3-dicapryoyl-2-oleoyl-sn-glycerol (COC). Transesterification conditions investigated were residence times (i.e., 15, 30, and 60 min) and enzyme loadings (2.0 and 4.5 g).  The highest yield of ECN 32 (13%) and transesterification degree (71%) were obtained at residence time of 15 mins for both enzyme loadings. Longer residence time seemed to facilitate lipid hydrolysis over transesterification. This was indicated by the number of peaks appearing in the high-performance liquid chromatography (HPLC) chromatograms and the reduction of fat slip melting point (SMP). Additionally, the highest productivity was obtained at 2.0 g enzyme loading. Conclusively, this study has demonstrated the potential use of packed-bed reactor with immobilized Lipozyme TL IM for continuous synthesis of MLM-SLs especially TAG with ECN32.


Author(s):  
Arturo Schiaffino ◽  
V. M. Krushnarao Kotteda ◽  
Vinod Kumar ◽  
Arturo Bronson ◽  
Sanjay Shantha-Kumar

Abstract In the manufacturing of metal matrix composites (MMC), liquid-metal reactive infusion with a solid mesh or particles composed of ceramic or metal may be used. The objective of this study is to determine the uncertainty quantification of the modeling of liquid hafnium infusion to expedite the processing and improve properties of MMCs ultimately. Uncertainty quantification (UQ) characterized the uncertainty scientifically especially for high-performance computing with observed physics and/or chemistry of the phenomena and predicted from estimated parameters. In this work, molten hafnium infusing through a boron carbide packed bed is modeled to optimize the manufacturing of components used for a hypersonic vehicle. The creation of molten matrix composites by the infiltration of molten metal represents a formidable challenge to be accurately modeled. First, the structural randomness associated with porous mediums complicates the prediction of the flow passing through it. Secondly, the properties of the molten metal could vary inside our control volume, since the temperature inside the control volume is not constant. Also, there are several chemical reactions and solidification rates occurring in during the impregnation. Given the recent advances in high-performance computing, an in-house pore network simulator are implemented along with Dakota, an open-source, exascale software, to determine the optimal parameters (e.g., porosity and temperature) and uncertainty quantification for the modeling.


Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 472 ◽  
Author(s):  
Ana M. Chávez ◽  
Ana R. Ribeiro ◽  
Nuno F. F. Moreira ◽  
Adrián M. T. Silva ◽  
Ana Rey ◽  
...  

Numerous contaminants of emerging concern (CECs) have been found in different water bodies. Directive 2013/39/EU and Decision 2018/840/EU are consequently being implemented in the field of water policies. Twelve CECs (e.g., isoproturon, ciprofloxacin, and clarithromycin are among those listed) were detected in a municipal wastewater secondary effluent by means of solid phase extraction and ultra-high-performance liquid chromatography with tandem mass spectrometry (SPE-UHPLC-MS/MS). Different advanced oxidation processes (AOPs), based on the combination of ozone, UVA-LED and powdered TiO2, were investigated for their removal in a semi-batch operation. In addition, TiO2-coated glass rings (P25R) were characterized with different techniques (SEM, WDXRF) and used for continuous mode operation in a packed bed reactor (PBR). Among the AOPs studied, ozone-based processes were found to be more efficient than heterogeneous photocatalysis. A kinetic study was performed showing that direct ozonation is the main oxidation pathway for CEC removal. Ozone was successfully decomposed in combination with UVA-LED and P25R, resulting in an apparent rate constant of 3.2 × 10−2 s−1 higher than in the O3/LED system (1.0 × 10−3 s−1) or with ozone alone (8.6 × 10−5 s−1). Hydroxyl radical reaction could prevail over direct ozone reaction for the most refractory compounds (e.g., isoproturon).


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