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Daejeon, South Korea

Boga D.A.,University Utrecht | Oord R.,University Utrecht | Beale A.M.,University Utrecht | Chung Y.-M.,SK Innovation | And 2 more authors.
ChemCatChem | Year: 2013

Monometallic Pt and bimetallic Pt-Cu catalysts supported on Mg(Al)O mixed oxides, obtained by calcination of the corresponding layered double hydroxides (LDHs), were prepared and tested in the aqueous-phase reforming (APR) of glycerol. The effect of the Mg/Al ratio and calcination temperature of the LDH support, as well as the effect of varying Pt and Cu amounts on glycerol reforming, was investigated. The use of a basic support increases the selectivity to hydrogen and the use of a Pt-Cu bimetallic catalyst results in a decrease in alkane formation. The 0.9wt.% Pt-0.4wt.% Cu/Mg(Al)O_2.95 catalyst system with an Mg(Al)O mixed oxide support obtained by the calcination of the corresponding LDH material with Mg/Al ratio of 2.95 at 673K, showed higher hydrogen selectivity (55.3%) and lower methane production (1.9%) after 5h reaction than the benchmark Pt/Al2O3 catalyst (49.4% and 5.6%, respectively). Catalyst characterization by extended X-ray absorption fine structure (EXAFS) spectroscopy showed a bimetallic interaction between Pt and Cu. The bimetallic interaction is thought to be responsible for the lowered methane formation and, ultimately, the high hydrogen selectivity observed. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Choi J.-H.,Konkuk University | Youn P.S.,Konkuk University | Brahimi D.,Konkuk University | Jeon Y.-W.,SK Innovation | And 2 more authors.
Korean Journal of Chemical Engineering | Year: 2012

We developed a mathematical model to discuss the performance of chemical looping combustion (CLC) of methane in continuous bubbling fluidized-beds. The model considers the particle population balance, oxidation and reduction rate of particles in fluidized beds. It also considers utilization efficiency of oxygen carrier (OC) particles, residence time of particles in each reactor, and particle size in reaction rate. The model was applied for a bubbling coreannulus fluidized-bed process. The core bed was the fuel reactor (0. 08 m-i. d., 2. 1 m-height) and the annulus bed was the air reactor (0. 089 m-i. d., 0. 15 m-o. d., 1. 6 m-height). The process employed a type of Ni-based OC particles. The present model agrees reasonably well with the combustion efficiency measured in the process. Simulation was performed to investigate the effects of some variables for the process. The present model revealed that the range of circulation rate of OC particles for achieving complete combustion determined the operating range of the CLC system. The minimum circulation rate of OC particles for complete combustion decreased in the considered operating range as temperature or bed mass increased in the fuel reactor. A large mass of the fuel bed was necessary to obtain complete combustion at low fuel reactor temperature. The fresh feed rate of OC particles for steady state operation increased in complete combustion condition as temperature or static bed height or gas velocity increased. © 2011 Korean Institute of Chemical Engineers, Seoul, Korea. Source


Lee S.,SK Innovation | Kam S.I.,Louisiana State University
Offshore Technology Conference, Proceedings | Year: 2015

Foam injection is a promising means to improve field-scale displacement efficiency, especially when a reservoir consists of multiple geological layers, the connectivity of which is minimal or absent due to the shale layers embedded in between. This study is devoted to investigating how foam EOR processes work in such heterogeneous and layered reservoir systems overcoming subsurface heterogeneity by using fractional flow analysis. This study first shows how to interpret theoretically the injection of surfactant preflush and following foams into a single-layer system at pre-specified rock and fluid properties, and then extends the knowledge gained into multi-layer systems where the properties vary in different layers. The results in general show that the mechanisms of foam displacement strongly depends on foam properties such as gas-phase mobility reduction factors (MRF), limiting water saturation (Sw∗), and critical oil saturation (So∗) as well as petrophysical properties of individual layers such as porosity (φ), permeability (k), relative permeability, capillary pressure (Pc) and so on. The overall sweep efficiency in a multi-layer system is very difficult to predict because of the complexity, but the mathematical framework presented in this study is shown to handle the problem successfully and reliably. A 1D foam simulator developed in this study is used for verification purpose. Copyright 2015, Offshore Technology Conference. Source


Boland N.L.,University of Newcastle | Eberhard A.C.,RMIT University | Engineer F.G.,SK Innovation | Fischetti M.,University of Padua | And 2 more authors.
Mathematical Programming Computation | Year: 2014

The feasibility pump (FP) has proved to be an effective method for finding feasible solutions to mixed integer programming problems. FP iterates between a rounding procedure and a projection procedure, which together provide a sequence of points alternating between LP feasible but fractional solutions, and integer but LP infeasible solutions. The process attempts to minimize the distance between consecutive iterates, producing an integer feasible solution when closing the distance between them. We investigate the benefits of enhancing the rounding procedure with a clever integer line search that efficiently explores a large set of integer points. An extensive computational study on benchmark instances demonstrates the efficacy of the proposed approach. © 2014, Springer-Verlag Berlin Heidelberg and Mathematical Optimization Society. Source


Lee K.,Korea Institute of Geoscience and Mineral Resources | Jung S.,SK Innovation | Choe J.,Seoul National University
Journal of Petroleum Science and Engineering | Year: 2016

Reservoir characterization is one of the most important works for decision makings in petroleum industry. Ensemble Kalman filter (EnKF) has been researched for history matching, but it requires lots of simulation time. Although ensemble smoother (ES) is much faster than EnKF, it is hard to apply for complex models such as channelized reservoirs due to overshooting and filter divergence problems. The concept of clustered covariance has been proposed only for 2D reservoirs using ES to keep simulation time low and improve history matching results. In this research, a distance-based method and ES with clustered covariance (ESC) are applied to 3D channel fields for the first time. At first, the distance-based method, which consists of Hausdorff distance, multidimensional scaling, and K-means clustering, is successfully applied to 3D fields. Ensemble members in the same group show similar facies distributions and connectivity. Secondly, ESC is compared to a standard EnKF and ES. Updated models from the two methods cannot preserve bimodal distribution and future productions of them show biased predictions. Due to vertical heterogeneity and bimodal distribution of reservoir permeability, it is hard to assimilate reliably for EnKF and ES methods alone in 3D channelized reservoirs. However, ESC manages overshooting problem in ES and preserves bimodal distribution with reliable uncertainty ranges in reservoir performances. It requires about 4% of history matching time of EnKF for the cases tested. Furthermore, only 10 reservoir models selected from the distance-based clustering can replace 200 total ensembles for uncertainty quantification. Therefore, ESC can be applicable to 3D channelized reservoirs with geological uncertainties. © 2016 Elsevier B.V. Source

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