Abhay Gupta, Mugdha Ambast and Michael P. Harold*,
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引用次数: 2
Abstract
The spatiotemporal features of the multifunctional monolithic lean hydrocarbon NOx trap (LHCNT), for eliminating NOx (x = 1 and 2) and ethylene (C2H4), are examined using spatially resolved mass spectrometry (SpaciMS), spanning the sequentially positioned passive NOx adsorber (PNA; Pd/SSZ-13), hydrocarbon trap (HCT; Pd/BEA), and oxidation catalyst (OC; Pt/Al2O3–CeO2). The overall LHCNT performance is captured in temporal trapping efficiency profiles, which show the integral NO and C2H4 uptake followed by delayed NO release along with NO and ethylene oxidation. Spatially resolved transient concentration profiles spanning uptake, release, and conversion of NO, H2, and C2H4, alone or as mixtures in feeds containing H2O, provide detailed insight into the transient coupling not attainable with effluent concentration monitoring alone. The PNA serves as the primary zone for NO uptake, followed by the OC and HCT. NO oxidation to NO2 occurs during NO uptake in the PNA due to Pd(II) reduction, while more extensive oxidation occurs in the OC at higher temperature. C2H4 uptake and oxidation occur in each of the functions with oxidation occurring the earliest (lowest temperature) in the OC. NO uptake in the PNA and HCT is negligibly affected by H2 but protracted oxidation of H2 during the temperature ramp delays NO release, suggesting persistence of NO bound on Pd(I). Both the PNA and HCT exhibit excellent C2H4 uptake, which diminishes in the presence of NO. Spatially resolved concentration data reveal several interesting features, such as high-temperature, sequential NO oxidation (by O2 to NO2) and C2H4 oxidation (by NO2 to NO + CO2) in the PNA. Simulated warmup experiments reveal that the LHCNT NO trapping is enhanced with C2H4 addition but that a reduction in space velocity may be needed to improve performance. A previously developed PNA model predicts satisfactorily the main features of spatially resolved NO and NO + C2H4 data.
期刊介绍：
）ACS Engineering Au is an open access journal that reports significant advances in chemical engineering applied chemistry and energy covering fundamentals processes and products. The journal's broad scope includes experimental theoretical mathematical computational chemical and physical research from academic and industrial settings. Short letters comprehensive articles reviews and perspectives are welcome on topics that include:Fundamental research in such areas as thermodynamics transport phenomena (flow mixing mass & heat transfer) chemical reaction kinetics and engineering catalysis separations interfacial phenomena and materialsProcess design development and intensification (e.g. process technologies for chemicals and materials synthesis and design methods process intensification multiphase reactors scale-up systems analysis process control data correlation schemes modeling machine learning Artificial Intelligence)Product research and development involving chemical and engineering aspects (e.g. catalysts plastics elastomers fibers adhesives coatings paper membranes lubricants ceramics aerosols fluidic devices intensified process equipment)Energy and fuels (e.g. pre-treatment processing and utilization of renewable energy resources; processing and utilization of fuels; properties and structure or molecular composition of both raw fuels and refined products; fuel cells hydrogen batteries; photochemical fuel and energy production; decarbonization; electrification; microwave; cavitation)Measurement techniques computational models and data on thermo-physical thermodynamic and transport properties of materials and phase equilibrium behaviorNew methods models and tools (e.g. real-time data analytics multi-scale models physics informed machine learning models machine learning enhanced physics-based models soft sensors high-performance computing)
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