Showing papers in "Aiche Journal in 2015"

Predicting multicomponent adsorption: 50 years of the ideal adsorbed solution theory

Abstract: Describing multi-component adsorption is fundamental to using sorption in any chemical separation. 50 years ago, Myers and Prausnitz made a seminal contribution to characterization and prediction of multi-component adsorption by introducing Ideal Adsorbed Solution Theory (IAST). Here, we give an overview of IAST, highlighting its continued role as a benchmark method in describing adsorption using illustrative examples from a variety of experimental and molecular modeling studies. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2757–2762, 2015

Concurrent monitoring of operating condition deviations and process dynamics anomalies with slow feature analysis

Abstract: Latent variable (LV) models have been widely used in multivariate statistical process monitoring. However, whatever deviation from nominal operating condition is detected, an alarm is triggered based on classical monitoring methods. Therefore, they fail to distinguish real faults incurring dynamics anomalies from normal deviations in operating conditions. A new process monitoring strategy based on slow feature analysis (SFA) is proposed for the concurrent monitoring of operating point deviations and process dynamics anomalies. Slow features as LVs are developed to describe slowly varying dynamics, yielding improved physical interpretation. In addition to classical statistics for monitoring deviation from design conditions, two novel indices are proposed to detect anomalies in process dynamics through the slowness of LVs. The proposed approach can distinguish whether the changes in operating conditions are normal or real faults occur. Two case studies show the validity of the SFA-based process monitoring approach. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3666–3682, 2015

A new drag correlation from fully resolved simulations of flow past monodisperse static arrays of spheres

Abstract: Fully resolved simulations of flow past fixed assemblies of monodisperse spheres in face-centered-cubic array or random configurations, are performed using an iterative immersed boundary method. A methodology has been applied such that the computed gas–solid force is almost independent of the grid resolution. Simulations extend the previously similar studies to a wider range of solids volume fraction ( inline image[0.1, 0.6]) and Reynolds number (Re inline image[50, 1000]). A new drag correlation combining the existed drag correlations for low-Re flows and single-sphere flows is proposed, which fits the entire dataset with an average relative deviation of 4%. This correlation is so far the best possible expression for the drag force in monodisperse static arrays of spheres, and is the most accurate basis to introduce the particle mobility for dynamic gas–solid systems, such as in fluidized beds.

Air separation with cryogenic energy storage: Optimal scheduling considering electric energy and reserve markets

Abstract: The concept of cryogenic energy storage (CES) is to store energy in the form of liquid gas and vaporize it when needed to drive a turbine. Although CES on an industrial scale is a relatively new approach, the technology is well known and essentially part of any air separation unit that utilizes cryogenic separation. In this work, the operational benefits of adding CES to an existing air separation plant are assessed. Three new potential opportunities are investigated: (1) increasing the plant's flexibility for load shifting, (2) storing purchased energy and selling it back to the market during higher-price periods, and (3) creating additional revenue by providing operating reserve capacity. A mixed-integer linear programming scheduling model is developed and a robust optimization approach is applied to model the uncertainty in reserve demand. The proposed model is applied to an industrial case study, which shows significant potential economic benefits. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1547–1558, 2015

A model for gas transport in microfractures of shale and tight gas reservoirs

Abstract: A model for gas transport in microfractures of shale and tight gas reservoirs is established. Slip flow and Knudsen diffusion are coupled together to describe general gas transport mechanisms, which include continuous flow, slip flow, transitional flow, and Knudsen diffusion. The ratios of the intermolecular collision frequency and the molecule-wall collision frequency to the total collision frequency are defined as the weight coefficients of slip flow and Knudsen diffusion, respectively. The model is validated by molecular simulation results. The results show that: (1) the model can reasonably describe the process of the mass transform of different gas transport mechanisms; (2) fracture geometry significantly impacts gas transport. Under the same fracture aperture, the higher the aspect ratio is, the stronger the gas transport capacity, and this phenomenon is more pronounced in the cases with higher gas pressure and larger fracture aperture. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2079–2088, 2015

Optimal design and operations of supply chain networks for water management in shale gas production: MILFP model and algorithms for the water-energy nexus

Abstract: The optimal design and operations of water supply chain networks for shale gas production is addressed. A mixed-integer linear fractional programming (MILFP) model is developed with the objective to maximize profit per unit freshwater consumption, such that both economic performance and water-use efficiency are optimized. The model simultaneously accounts for the design and operational decisions for freshwater source selection, multiple transportation modes, and water management options. Water management options include disposal, commercial centralized wastewater treatment, and onsite treatment (filtration, lime softening, thermal distillation). To globally optimize the resulting MILFP problem efficiently, three tailored solution algorithms are presented: a parametric approach, a reformulation-linearization method, and a novel Branch-and-Bound and Charnes–Cooper transformation method. The proposed models and algorithms are illustrated through two case studies based on Marcellus shale play, in which onsite treatment shows its superiority in improving freshwater conservancy, maintaining a stable water flow, and reducing transportation burden. © 2014 American Institute of Chemical Engineers AIChE J, 61: 1184–1208, 2015

Co‐gasification of woody biomass and sewage sludge in a fixed‐bed downdraft gasifier

Abstract: Experimental and numerical studies of cogasification of woody biomass and sewage sludge have been carried out. The gasification experiments were performed in a fixed-bed downdraft gasifier and the experimental results show that 20 wt % dried sewage sludge in the feedstock was effectively gasified to generate producer gas comprising over 30 vol % of syngas with an average lower heating value of 4.5 MJ/Nm3. Further increasing sewage sludge content to 33 wt % leads to the blockage of gasifier, which is resulted from the formation of agglomerated ash. The numerical models were then developed to simulate the reactions taking place in four different zones of the gasifier (i.e., drying, pyrolysis, combustion, and reduction zones) and to predict the producer gas composition and cold gas efficiency. The deviation between the numerical and experimental results obtained was lower than 10%. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2508–2521, 2015

A hierarchical method to integrated solvent and process design of physical CO2 absorption using the SAFT‐γ Mie approach

Abstract: Molecular-level decisions are increasingly recognized as an integral part of process design. Finding the optimal process performance requires the integrated optimization of process and solvent chemical structure, leading to a challenging mixed-integer nonlinear programming (MINLP) problem. The formulation of such problems when using a group contribution version of the statistical associating fluid theory, SAFT-γ Mie, to predict the physical properties of the relevant mixtures reliably over process conditions is presented. To solve the challenging MINLP, a novel hierarchical methodology for integrated process and solvent design (hierarchical optimization) is presented. Reduced models of the process units are developed and used to generate a set of initial guesses for the MINLP solution. The methodology is applied to the design of a physical absorption process to separate carbon dioxide from methane, using a broad selection of ethers as the molecular design space. The solvents with best process performance are found to be poly(oxymethylene)dimethylethers. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3249–3269, 2015

Probabilistic slow feature analysis‐based representation learning from massive process data for soft sensor modeling

Abstract: Latent variable (LV) models provide explicit representations of underlying driving forces of process variations and retain the dominant information of process data In this study, slow features as temporally correlated LVs are derived using probabilistic slow feature analysis Slow features evolving in a state-space form effectively represent nominal variations of processes, some of which are potentially correlated to quality variables and hence help improving the prediction performance of soft sensors An efficient EM algorithm is proposed to estimate parameters of the probabilistic model, which turns out to be suitable for analyzing massive process data Two criteria are ∗To whom correspondence should be addressed †Tsinghua University ‡University of Alberta 1 also proposed to select quality-relevant slow features The validity and advantages of the proposed method are demonstrated via two case studies

Designing of anion-functionalized ionic liquids for efficient capture of SO2 from flue gas

Abstract: Five kinds of anion-functionalized ionic liquids (ILs) with different basicity and substituent were selected, prepared and applied in the capture of SO2 from flue gas, where the concentration of SO2 is only 2000 ppm. The effect of the anion on SO2 absorption capacity, desorption residue, and available absorption capacity under 2000 ppm was investigated. The relationship between available absorption capacity and absorption enthalpy was also studied. Through a combination of thermodynamic analysis and quantum calculation, the results indicated that the effect of the cation in the IL on absorption enthalpy was significant. However, the effect of chain length in the cation was weak. Hence, a new IL with low molecular weight, [P4442][Tetz], was further designed and applied for the capture of SO2, which shows the high absorption capacity of 0.18 g SO2 per g IL and excellent reversibility for 2000 ppm SO2. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2028–2034, 2015

Systematic design of an extractive distillation for maximum‐boiling azeotropes with heavy entrainers

Abstract: Extractive distillation is one of the most attractive approaches for separating azeotropic mixtures. Few contributions have been reported to design an extractive distillation for separating maximum-boiling azeotropes and no systematic approaches for entrainer screening have been presented. A systematic approach to design of two-column extractive distillation for separating azeotropes with heavy entrainers has been proposed. A thermodynamic feasibility analysis for azeotropes with potential heavy entrainers was first conducted. Then, five important properties are selected for entrainer evaluation. Fuzzy logic and develop membership functions to calculate attribute values of selected properties have been used. An overall indicator for entrainer evaluation is proposed and a ranking list is generated. Finally, the top five entrainers from the ranking list have been selected and use process optimization techniques to further evaluate selected entrainers and generate an optimal design. The capability of the proposed method is illustrated using the separation of acetone–chloroform azeotropes with five potential entrainers.

State of health estimation of lithium-ion batteries: A multiscale Gaussian process regression modeling approach

Abstract: Accurate state of health (SOH) estimation in lithium-ion batteries, which plays a significant role not only in state of charge (SOC) estimation but also in remaining useful life (RUL) prognostics is studied. SOC estimation and RUL prognostics often require one-step-ahead and long-term SOH prediction, respectively. A systematic multiscale Gaussian process regression (GPR) modeling method is proposed to tackle accurate SOH estimation problems. Wavelet analysis method is utilized to decouple global degradation, local regeneration and fluctuations in SOH time series. GPR with the inclusion of time index is utilized to fit the extracted global degradation trend, and GPR with the input of lag vector is designed to recursively predict local regeneration and fluctuations. The proposed method is validated through experimental data from lithium-ion batteries degradation test. Both one-step-ahead and multi-step-ahead SOH prediction performances are thoroughly evaluated. The satisfactory results illustrate that the proposed method outperform GPR models without trend extraction. It is thus indicated that the proposed multiscale GPR modeling method can not only be greatly helpful to both RUL prognostics and SOC estimation for lithium-ion batteries, but also provide a general promising approach to tackle complex time series prediction in health management systems. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1589–1600, 2015

An electrolyte CPA equation of state for mixed solvent electrolytes

Abstract: Despite great efforts over the past decades, thermodynamic modeling of electrolytes in mixed solvents is still a challenge today. The existing modeling frameworks based on activity coefficient models are data-driven and require expert knowledge to be parameterized. It has been suggested that the predictive capabilities could be improved through the development of an electrolyte equation of state. In this work, the Cubic Plus Association (CPA) Equation of State is extended to handle mixtures containing electrolytes by including the electrostatic contributions from the Debye–Huckel and Born terms using a self-consistent model for the static permittivity. A simple scheme for parameterization of salts with a limited number of parameters is proposed and model parameters for a range of salts are determined from experimental data of activity and osmotic coefficients as well as freezing point depression. Finally, the model is applied to predict VLE, LLE, and SLE in aqueous salt mixtures as well as in mixed solvents. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2933–2950, 2015

Engineering red‐blood‐cell‐membrane–coated nanoparticles for broad biomedical applications

Abstract: R ed blood cells (RBCs) are nature’s long-circulating delivery vehicles. They possess various remarkable properties and continue to inspire the design and engineering of man-made delivery systems. Inherently suited for intravascular delivery, RBCs are intrinsically biocompatible, biodegradable, and nonimmunogenic. They form natural compartments capable of protecting encapsulated cargos, and this allows them to circulate in the bloodstream for a long period of time (up to 120 days). In addition, their semipermeable membrane affords sustained release to smallmolecule drugs, yet they are ideal for retaining large proteins while providing them access to the substrates. Delivery vehicles possessing one or several of these properties have long been desired for efficacious therapeutics. A long-sought strategy for RBC-mimicking delivery vehicles is to load natural RBCs with therapeutic agents without compromising the structural integrity and biological functions of the RBCs. Various loading techniques, including automated loading devices, have been developed to enable the encapsulation of payloads with molecular weights of over 180 kDa into RBCs with maintenance of the carriers’ biological competence. In addition to the interior of RBCs, their exterior surface has also been coupled with therapeutic molecules, either covalently or physically, for various delivery applications. These RBC-based delivery vehicles, namely carrier RBCs, have been developed for the delivery of numerous therapeutic agents, including proteins, nucleic acids, and small-molecule drugs. Several of them have entered clinical tests to treat various diseases, including cancers and enzyme deficiencies. Meanwhile, advances in molecular biology have provided unprecedented understanding of the connections between the physicochemical characteristics of RBCs and their biological functions. This understanding, in turn, has inspired researchers to model drug carriers after RBCs. Designs that mimic the physicochemical characteristics and biological functions of RBCs, particularly those that enable their passage through narrow constrictions while maintaining a long in vivo survival, have been integrated into the engineering of drug carriers and have resulted in novel delivery systems with improved drug tolerability, circulation lifetime, and efficacy. Recently, the pursuit of RBC-mimicking nanoparticles led us to develop an intriguing approach for functionalizing synthetic nanoparticles with natural RBC membranes. In this approach, we first collected intact cellular membranes and then coated them onto polymeric nanoparticle cores, such as those made from poly(lactic-co-glycolic acid) (PLGA); this resulted in red-blood-cell-membrane–coated nanoparticles (RBC-NPs; Figure 1). Our aim was to fabricate cellmimicking nanoparticles through a top-down approach that bypassed the labor-intensive processes of protein identification, purification, and conjugation. The natural membranes also provide a bilayered medium for transmembrane protein anchorage while preventing common chemical modifications that could compromise the integrity and functionalities of these proteins. The independent preparation of cellular membranes and particle cores before coating offers a new level of engineering flexibility toward highly functional biomimetic nanoparticles. Since their initial development, RBC-NPs have provided an unprecedented capability for harnessing the natural functionalities of native cells that would otherwise be difficult to replicate. They have since inspired us to develop novel nanotherapeutics for better disease intervention. In this Perspective, we review our recent progress in developing RBC-NPs for three distinct biomedical applications: long-circulating nanocarriers for drug delivery, biomimetic nanosponges for detoxification, and nanotoxoids for safe and effective toxin vaccination.

Multiobjective optimization of product and process networks: General modeling framework, efficient global optimization algorithm, and case studies on bioconversion

Abstract: A comprehensive optimization model that can determine the most cost-effective and environmentally sustainable production pathways in an integrated processing network is needed, especially in the bioconversion space. We develop the most comprehensive bioconversion network to date with 193 technologies and 129 materials/compounds for fuels production. We consider the tradeoff between scaling capital and operating expenditures (CAPEX and OPEX) as well as life cycle environmental impacts. Additionally, we develop a general network-based modeling framework with nonconvex terms for CAPEX. To globally optimize the nonlinear program with high computational efficiency, we develop a specialized branch-and-refine algorithm based on successive piecewise linear approximations. Two case studies are considered. The optimal pathways have profits from −$12.9 to $99.2M/yr, and emit 791 ton CO2-eq/yr to 31,571 ton CO2-eq/yr. Utilized technologies vary from corn-based fermentation to pyrolysis. The proposed algorithm reduces computational time by up to three orders of magnitude compared to general-purpose global optimizers. © 2014 American Institute of Chemical Engineers AIChE J, 61: 530–554, 2015

Catalytic hydrothermal liquefaction of D. tertiolecta for the production of bio‐oil over different acid/base catalysts

Abstract: In this article, two acid catalysts (ZrO2/SO42− and HZSM-5) and two base catalysts (MgO/MCM-41 and KtB) were used in catalytic hydrothermal liquefaction (HTL) of Dunaliella tertiolecta (D. tertiolecta) for the production of bio-oil. The results indicated that the acid/base property of the catalyst plays a crucial role in the catalytic HTL process, and the base catalyst is conducive to the improvement of conversion and bio-oil yield. When KtB was used as the catalyst, the maximum conversion and bio-oil yield was 94.84 and 49.09 wt %, respectively. The detailed compositional analysis of the bio-oil was performed using thermogravimetric analysis, elemental analysis, FT-IR, and GC-MS. The compositional analysis results showed that the introduction of catalyst is beneficial for reducing the fixed carbon content in the bio-oil, and the structure of catalyst influences on the bio-oil composition and boiling point distribution. Based on our results and previous studies, the probable catalytic HTL microalgae model over various catalysts can be described that the main chemical reactions include ketonization, decarboxylic, dehydration, ammonolysis, and so forth. with HZSM-5 and MgO/MCM-41 as the catalyst; the cyclodimerization, decomposition, Maillard reaction, and ketonization are the main reactions with ZrO2/SO42− as the catalyst; the dehydration, ammonolysis, Maillard reaction, and ketonization can occur with KtB as the catalyst. Therefore, a plausible reaction mechanism of the main chemical component in D. tertiolecta is proposed. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1118–1128, 2015

Ni‐Al2O3/Ni‐foam catalyst with enhanced heat transfer for hydrogenation of CO2 to methane

Abstract: Monolithic Ni-Al2O3/Ni-foam catalyst is developed by modified wet chemical etching of Ni-foam, being highly active/selective and stable in strongly exothermic CO2 methanation process. The as-prepared catalysts are characterized by x-ray diffraction scanning electron microscopy, inductively coupled plasma atomic emission spectrometry, and H2-temperature programmed reduction-mass spectrometry. The results indicate that modified wet chemical etching method is working efficiently for one-step creating and firmly embedding NiO-Al2O3 composite catalyst layer (∼2 μm) into the Ni-foam struts. High CO2 conversion of 90% and high CH4 selectivity of >99.9% can be obtained and maintained for a feed of H2/CO2 (molar ratio of 4/1) at 320°C and 0.1 MPa with a gas hourly space velocity of 5000 h−1, throughout entire 1200 h test over 10.2 mL such monolithic catalysts. Computational fluid dynamics calculation and experimental measurement consistently confirm a dramatic reduction of “hotspot” temperature due to enhanced heat transfer. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4323–4331, 2015

Pyrolysis of heavy oil in the presence of supercritical water: The reaction kinetics in different phases

Abstract: In the presence of supercritical water (SCW) and N2, the pyrolysis of heavy oil was investigated to distinguish the difference in the reaction kinetics between the upgrading in the SCW and oil phases. The pyrolysis in the SCW phase is faster than that in the oil phase, but the reaction in whichever phase is retarded by vigorous stirring. The pyrolysis can be preferably described by a four-lump kinetic model consisting of the condensation of maltenes and asphaltenes in series. In the SCW phase, highly dispersed asphaltenes are isolated by water clusters from maltenes dissolved in SCW surroundings, by which the condensation of asphaltenes is drastically accelerated. Benefited from excellent mass transfer environments in SCW, the condensation of maltenes is promoted simultaneously. The introduction of SCW into the pyrolysis of heavy oil results in an effectively increased upgrading efficiency, but its influence on the properties of equilibrium liquid products is minor. © 2014 American Institute of Chemical Engineers AIChE J, 61: 857–866, 2015

Deciphering and handling uncertainty in shale gas supply chain design and optimization: Novel modeling framework and computationally efficient solution algorithm

Abstract: The optimal design and operations of shale gas supply chains under uncertainty of estimated ultimate recovery (EUR) is addressed. A two-stage stochastic mixed-integer linear fractional programming (SMILFP) model is developed to optimize the levelized cost of energy generated from shale gas. In this model, both design and planning decisions are considered with respect to shale well drilling, shale gas production, processing, multiple end-uses, and transportation. To reduce the model size and number of scenarios, we apply a sample average approximation method to generate scenarios based on the real-world EUR data. In addition, a novel solution algorithm integrating the parametric approach and the L-shaped method is proposed for solving the resulting SMILFP problem within a reasonable computational time. The proposed model and algorithm are illustrated through a case study based on the Marcellus shale play, and a deterministic model is considered for comparison. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3739–3755, 2015

A compact photomicroreactor design for kinetic studies of gas-liquid photocatalytic transformations

Abstract: Yuanhai Su and Volker HesselMicro Flow Chemistry and Process Technology, Dept. of Chemical Engineering and Chemistry, EindhovenUniversity of Technology, Den Dolech 2, 5600 MB Eindhoven, The NetherlandsTimothy No€elMicro Flow Chemistry and Process Technology, Dept. of Chemical Engineering and Chemistry, EindhovenUniversity of Technology, Den Dolech 2, 5600 MB Eindhoven, The NetherlandsDept. of Organic Chemistry, Ghent University, Krijgslaan 281 (S4), 9000 Gent, BelgiumDOI 10.1002/aic.14813Published online in Wiley Online Library (wileyonlinelibrary.com)A compact photomicroreactor assembly consisting of a capillary microreactor and small-scale light emitting diodes wasdeveloped for the study of reaction kinetics in the gas-liquid photocatalytic oxidation of thiophenol to phenyl disulfidewithin Taylor flow. The importance of photons was convincingly shown by a suction phenomenon due to the fast con-sumption of oxygen. Mass transfer limitations were evaluated and an operational zone without mass transfer effects waschosen to study reaction kinetics. Effects of photocatalyst loading and light sources on the reaction performance wereinvestigated. Reaction kinetic analysis was performed to obtain reaction orders with respect to both thiophenol and oxy-gen based on heterogeneous and homogeneous experimental results, respectively. The Hatta number further indicatedelimination of mass transfer limitations. Reaction rate constants at different photocatalyst loadings and different photonflux were calculated. Furthermore, the advantages of this photomicroreactor assembly for studying gas-liquid photocata-lytic reaction kinetics were demonstrated as compared with batch reactors.

Application of polyethylenimine-impregnated solid adsorbents for direct capture of low-concentration CO2

Abstract: A systematic study of CO2 capture on the amine-impregnated solid adsorbents is carried out at CO2 concentrations in the range of 400–5000 ppm, relating to the direct CO2 capture from atmospheric air. The commercially available polymethacrylate-based HP2MGL and polyethylenimine are screened to be the suitable support and amine, respectively, for preparation of the adsorbent. The adsorbents exhibit an excellent saturation adsorption capacity of 1.96 mmol/g for 400 ppm CO2 and 2.13 mmol/g for 5000 ppm CO2. Moisture plays a promoting effect on CO2 adsorption but depends on the relative humidity. The presence of O2 would lead to the decrease of adsorption capacity but do not affect the cyclic performance. The diffusion additive is efficient to improve the adsorption capacity and cyclic performance. Moreover, the adsorbents can be easily regenerated under a mild temperature. This study may have a positive impact on the design of high-performance adsorbents for CO2 capture from ambient air. © 2014 American Institute of Chemical Engineers AIChE J, 61: 972–980, 2015

Investment optimization model for freshwater acquisition and wastewater handling in shale gas production

Abstract: Major challenges of water use in the drilling and fracturing process in shale gas production are large volumes required in a short-period of time and the nonsteady nature of wastewater treatment. A new mixed-integer linear programming (MILP) model for optimizing capital investment decisions for water use for shale gas production through a discrete-time representation of the State-Task Network is presented. The objective is to minimize the capital cost of impoundment, piping, and treatment facility, and operating cost including freshwater, pumping, and treatment. The goal is to determine the location and capacity of impoundment, the type of piping, treatment facility locations and removal capability, freshwater sources, as well as the frac schedule. In addition, the impact of several factors such as limiting truck hauling and increasing flowback volume on the solution is examined. A case study is optimized to illustrate the application of the proposed formulation. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1770–1782, 2015

The generation of hydroxyl radicals by hydrogen peroxide decomposition on FeOCl/SBA‐15 catalysts for phenol degradation

Abstract: Iron oxychloride (FeOCl) supported on mesoporous silica (SBA-15), as a Fenton-like solid catalyst for phenol degradation, showed supreme activity for production of hydroxyl radical (HO·) by H2O2 decomposition, and the generation capacity was comparable to the conventional Fenton reagent (Fe2++H2O2). The structure of FeOCl was characterized with spectroscopies. The generation of HO· species during the reaction was detected using 5,5-dimethyl-1-pyrroline N-oxide trapped electron paramagnetic resonance. Furthermore, the kinetics in detail was driven for the creation and diffusion of HO· by H2O2 decomposition over FeOCl, which follows a first-order rate through a two-step reaction. With the combination of the catalyst structure and kinetic parameters, the plausible mechanism for H2O2 decomposition during the oxidative degradation of phenol was rationalized. As a Fenton-like solid catalyst, FeOCl/SBA-15 is a promising alternative for the removal of low-level organic contaminates from water. © 2014 American Institute of Chemical Engineers AIChE J, 61: 166–176, 2015

Toward more cost‐effective and greener chemicals production from shale gas by integrating with bioethanol dehydration: Novel process design and simulation‐based optimization

Abstract: A novel process design for a more cost-effective, greener process for making chemicals from shale gas and bioethanol is presented. The oxidative coupling of methane and cocracking technologies are considered for converting methane and light natural gas liquids, into value-added chemicals. Overall, the process includes four process areas: gas treatment, gas to chemicals, methane-to-ethylene, and bioethanol-to-ethylene. A simulation-optimization method based on the NSGA-II algorithm for the life cycle optimization of the process modeled in the Aspen HYSYS is developed. An energy integration model is also fluidly nested using the mixed-integer linear programming. The results show that for a “good choice” optimal design, the minimum ethylene selling price is $655.1/ton and the unit global-warming potential of ethylene is 0.030 kg CO2-eq/kg in the low carbon shale gas scenario, and $877.2/ton and 0.360 kg CO2-eq/kg in the high carbon shale gas scenario. © 2014 American Institute of Chemical Engineers AIChE J, 61: 1209–1232, 2015

High activity and wide temperature window of Fe‐Cu‐SSZ‐13 in the selective catalytic reduction of NO with ammonia

Abstract: Fe-Cu-SSZ-13 catalysts were prepared by aqueous solution ion-exchange method based on the one-pot synthesized Cu-SSZ-13. The catalysts were applied to the selective catalytic reduction (SCR) of NO with NH3 and characterized by the means of XRD, UV-Vis, EPR, XPS, NH3-TPD, and so on. The selected Fe-Cu-SSZ-13-1 catalyst exhibited the high NO conversion (>90%) in the wide temperature range (225–625°C), which also showed good N2 selectivity and excellent hydrothermal stability. The results of XPS showed that the Cu and Fe species were in the internal and outer parts of the SSZ-13 crystals, respectively. The results of UV-Vis and EPR indicated that the monomeric Cu2+ ions coordinated to three oxygen atoms on the six-ring sites and Fe monomers are the real active species in the NH3-SCR reaction. Furthermore, the influence of intracrystalline mass-transfer limitations on the Fe-Cu-SSZ-13 catalysts is related to the location of active species in the SSZ-13 crystals. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3825–3837, 2015

Developing intermolecular‐potential models for use with the SAFT‐VR Mie equation of state

Abstract: A major advance in the statistical associating fluid theory (SAFT) for potentials of variable range (SAFT-VR) has recently been made with the incorporation of the Mie (generalized Lennard–Jones [LJ]) interaction between the segments comprising the molecules in the fluid (Lafitte et al. J. Chem. Phys. 2013;139:154504). The Mie potential offers greater versatility in allowing one to describe the softness/hardness of the repulsive interactions and the range of the attractions, which govern fine details of the fluid-phase equilibria and thermodynamic derivative properties of the system. In our current work, the SAFT-VR Mie equation of state is employed to develop models for a number of prototypical fluids, including some of direct relevance to the oil and gas industry: methane, carbon dioxide and other light gases, alkanes, alkyl benzenes, and perfluorinated compounds. A complication with the use of more-generic force fields such as the Mie potential is the additional number of parameters that have to be considered to specify the interactions between the model molecules, leading to a degree of degeneracy in the parameter space. A formal methodology to isolate intermolecular-potential models and assess the adequacy of the description of the thermodynamic properties in terms of the complex parameter space is developed. Fluid-phase equilibrium properties (the vapor pressure and saturated-liquid density) are chosen as the target properties in the refinement of the force fields; the predictive capability for other properties such as the enthalpy of vaporization, single-phase density, speed of sound, isobaric heat capacity, and Joule–Thomson coefficient, is appraised. It is found that an overall improvement of the representations of the thermophysical properties of the fluids is obtained using the more-generic Mie form of interaction; in all but the simplest of fluids, one finds that the LJ interaction is not the most appropriate. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2891–2912, 2015

Design and screening of ionic liquids for C2H2/C2H4 separation by COSMO-RS and experiments

Abstract: Ionic liquids (ILs) have been proposed as promising solvents for separating C2H2 and C2H4, but screening an industrially attractive IL with high capacity from numerous available ILs remains challenging. In this work, a rapid screening method based on COSMO-RS was developed. We also present an efficient strategy to improve the C2H2 capacity in ILs together with adequate C2H2/C2H4 selectivity with the aid of COSMO-RS. The essence of this strategy is to increase molecular free volume of ILs and simultaneously enhance hydrogen-bond basicity of anions by introducing flexible and highly asymmetric structures, which is validated by a new class of tetraalkylphosphonium ILs featuring long-chain carboxylate anions. At 298.1 K and 1 bar, the solubility of C2H2 in ILs reaches 0.476 mol/mol IL, very high for a physical absorption, with a selectivity of up to 21.4. The separation performance of tetraalkylphosphonium ILs to the mixture of C2H2/C2H4 was also evaluated. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2016–2027, 2015

Rigorous design of distillation columns using surrogate models based on Kriging interpolation

Abstract: The authors gratefully acknowledge the financial support of the Ministry of Economy and Competitiveness of Spain, under the project CTQ2012-37039-C02-02