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Low grade heat still widely exists in energy-intensive industrial parks, although good energy integration has been accomplished for individual processes or plants. Low grade heat is notably large but difficult to utilize because of the limitation of heat transfer and the scarcity of low grade heat sinks. Large scale utilization of low grade heat is very challenging for energy-intensive industries or industrial parks. A large scale low grade heat recovery, refrigeration, and utilization network system is introduced in this study to improve energy performance for industrial parks. In order to model the large scale system, the system is decomposed into three levels: pipe networks, refrigeration stations and absorption chillers. A mixed integer nonlinear programming model is presented that considers mass and energy networks, pipes, refrigeration stations, absorption chillers, and economic performance. The mathematical model is applied to the optimization and economic analysis for the low grade heat utilization in a petrochemical industrial park in China. The model can be solved in available time using the global solver. The solution results demonstrate the good economic performance of the new low grade heat recovery, refrigeration, and utilization network system for the industrial park. [ABSTRACT FROM AUTHOR]

A heterogeneous reaction mechanismbased on elementary reactionsteps is proposed for the prediction of pyrolytic carbon depositionin chemical vapor infiltration, involving 72 surface species and 277surface elementary reactions. A “prototype” gas-phasereaction is chosen to match with the corresponding surface reaction,and correction methods for kinetic data are also proposed for threekinds of surface reactions (i.e., surface/gas reactions, unimolecularsurface reactions, surface/surface reactions) in the present work.Simulation results of deposition kinetics and gas-phase compositionsof propane pyrolysis are validated by previously published experimentalresults of Marquaire’s group, with a surface to volume ratiofrom 5 to 175 cm–1and temperature from 1173 to1323 K. The reaction pathways of the heterogeneous surface reactionsand homogeneous gas-phase reactions are studied on the basis of thereaction flow rate analysis. An acceptable agreement indicates thatthe present heterogeneous reaction mechanism is reasonable, and acetylene,ethylene, and benzene are recognized as the main precursors of thepyrolytic carbon deposition at the present processing conditions. [ABSTRACT FROM AUTHOR]

High methane dissolution capacity in a liquid is important for methane storage and transformation. In this work, methane solubility in different ionic liquids (ILs) was studied and was found associated with IL's structural and physical properties. In imidazolium-based ILs, ILs containing C-F and long alkyl chain showed high methane solubility mainly due to lower surface tension and molar density. Reducing the surface tension of solvent by adding 0.16 mol of trimethyl-1-propanaminium iodide (FC-134) with respect to [Bmim][NTf2] increased methane solubility by 39.3%. In situ high-pressure attenuated total reflection Fourier transform infrared spectroscopic results indicated a reversible process of methane dissolution in the ILs. The antisymmetric C-H stretching band of dissolved methane in ILs showed highly prominent rotational-vibrational bands with high intensity and narrow half-peak width compared to gaseous methane. Induced interaction between methane and IL resulted in increased dipole variation strength and reduced methane molecular symmetry. The constant antisymmetric C-H stretching peak at 3016.85 cm-1 revealed an unconstrained methane rotation in the stable physical and chemical environment of IL. Methane insertion into the IL's intranetwork space needs activation energy to overcome the interaction of cation-anion network. Kinetic analysis of methane in [Bmim][NTf2] and [Bmim][HSO4] at different temperatures indicated that methane dissolution in these two ILs was a reversible first-order and very weak endothermic process and that methane dissolution required high activation energy in ILs with stronger cation-anion interaction. [ABSTRACT FROM AUTHOR]

We present measurements as part of the Southern Oxidant and Aerosol Study (SOAS) during which atmospheric aerosol particles were comprehensively characterized. We present results utilizing a Filter Inlet for Gases and AEROsol coupled to a chemical ionization mass spectrometer (CIMS). We focus on the volatility and composition of isoprene derived organic aerosol tracers and of the bulk organic aerosol. By utilizing the online volatility and molecular composition information provided by the FIGAERO--CIMS, we show that the vast majority of commonly reported molecular tracers of isoprene epoxydiol (IEPOX) derived secondary organic aerosol (SOA) is derived from thermal decomposition of accretion products or other low volatility organics having effective saturation vapor concentrations <10-3 pg m-3. In addition, while accounting for up to 30% of total submicrometer organic aerosol mass, the IEPOX-derived SOA has a higher volatility than the remaining bulk. That IEPOX-SOA, and more generally bulk organic aerosol in the Southeastern U.S. is comprised of effectively nonvolatile material has important implications for modeling SOA derived from isoprene, and for mechanistic interpretations of molecular tracer measurements. Our results show that partitioning theory performs well for 2-methyltetrols, once accretion product decomposition is taken into account. No significant partitioning delays due to aerosol phase or viscosity are observed, and no partitioning to particle-phase water or other unexplained mechanisms are needed to explain our results. [ABSTRACT FROM AUTHOR]

Ionic liquids have been widely studied as effective reaction media for the conversion of glucose or cellulose to 5-hydroxymethhylfurfural (5-HMF). However, the recovery of 5-HMF from ionic liquids, typically carried out by extraction, has been encountered with very low extraction efficiency, which limited the reusability of the solvents. Through this work, based on the model biphasic system that consists of 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) as the ionic liquid phase and methyl isobutyl ketone (MIBK) as the extractant phase, the dominant force that suppresses the extraction efficiency of 5-HMF was identified as being the strong hydrogen bonding between 5-HMF and [BMIM]Cl. Solvent mediation with functional promoters have been established as a new strategy to shift this force, resulting in improved extraction efficiency of 5-HMF from the ionic liquid. For example, with ethanol as a promoter, the distribution coefficient of 5-HMF was about 10 times higher than that without a promoter. [ABSTRACT FROM AUTHOR]

We report on the magnetotransportproperties of chemical vapordeposition grown films of interconnected Bi2Te3nanoplates. Similar to many other topological insulator (TI) materials,these granular Bi2Te3films exhibit a linearmagnetoresistance (LMR) effect which has received much recent attention.Studying samples with different degree of granularity, we find a universalcorrelation between the magnitude of the LMR and the average mobility(⟨μ⟩) of the films over nearly 2 orders of magnitudechange of ⟨μ⟩. The granularity controlled LMReffect here is attributed to the mobility fluctuation induced classicalLMR according to the Parish–Littlewood theory. These findingshave implications to both the fundamental understanding and magnetoresistivedevice applications of TI and small bandgap semiconductor materials. [ABSTRACT FROM AUTHOR]