A Combined Selective Adsorption and Ozonation Process for VOCs Removal from Air

A new hybrid process combining adsorption and ozonation is examined as an alternative treatment for Volatile Organic Compounds (VOC). The physical adsorption of ozone was clarified on a ZSM‐5 zeolite. Oxidation of two industrial solvents was achieved on two zeolites and followed with temperature profiles and sub‐products detection. Total regeneration of the fixed bed was achieved with a complete mineralization of organic compounds. Detection and identification of sub‐products traces allowed us to suspect oxidation reactive species. A mass balance on oxygen showed that all the inlet ozone was used for organic compounds oxidation. A selective oxidation was achieved, allowing the separation and the recovery of minor compound.     

Change of Young’s modulus of cold-deformed pure iron in a tensile test

Changes in Young’s modulus E (determined according to ASTM E-111) of polycrystalline pure iron deformed by a tensile test at room temperature are determined. From its original mean value, 210 GPa, E decreased with deformation to a mean value of 196 GPa at ɛ=0.060. Thereafter, slight recovery occurred and E stabilized to 198 GPa until the appearance of neck (ɛ=0.100). With the aim to examine the causes of this behavior, residual stresses and textures were measured and the dislocation structure was observed by transmission electron microscopy (TEM). Longitudinal residual stresses increased from the first step of deformation (ɛ=0.015) and remained constant until the samples fractured. There was no significant difference in texture throughout the deformation process, during which the increment of α fiber was smooth. Thus, the decrease of E cannot be attributed to residual stresses or textures. A relationship between dislocation arrangement and decrease of E is proposed. Following the model established by Mott, dislocations can bow out in their glide planes, giving extra elastic strain and thus a decrease of E. The increase of the dislocation density during the first steps of deformation lowers the E values, since the extra elastic strain increases. At higher strains, when the cellular dislocation structure has formed (between ɛ=0.060 and 0.080), the dislocations in cell interiors are capable of giving an extra elastic strain, whereas the dislocations trapped in the cell walls are not. However, the dislocation density in cell interiors is lower than the dislocation density in the early stages of deformation in which the cell structure has not been developed. This produces the slight recovery of E measured at these strains. From ɛ=0.080, the values of E stabilized since no changes in dislocation density in cell interiors are observed.     

Averaging model for cuttings transport in horizontal wellbores

This paper presents a theoretical analysis of the problem of cuttings transport for a two-region system composed of a fluid bed (ω-region) and a stationary bed of drill cuttings, which is considered as a porous medium (η-region) in the two-phase system. The ω-region is made up of a solid phase (σ-phase) dispersed in a continuos fluid phase (β-phase), while the η-region consists of a stationary solid phase (σ-phase) and a fluid phase (β-phase). The volume averaging method was applied in this study. Volume-averaged transport equations were derived for both the fluid bed and the porous medium regions. These equations are based on the non-local form of the volume-averaged momentum transport equation that is valid within the bounded region. Outside this region, the non-local form reduces to the classic volume-averaged transport equation. From these equations, a one-equation model was obtained, and the constraints that the one-equation model must satisfy were applied. For estimating the averaged pressure drop and the averaged velocity, the one-equation model was solved numerically by using the finite-difference technique in the implicit scheme. Numerical results are in agreement with experimental data and theoretical results reported in the literature.     

Modeling Wax Deposition in Pipelines

A multicomponent liquid-wax hydrodynamic model that incorporates phase equilibria and a full non-Newtonian behavior is proposed. In this model, molecular diffusion through the boundary layer induced by a temperature gradient between the liquid and the exterior pipe wall is assumed to be the dominant mechanism for deposition. Numerical solutions to the conservation equations for Newtonian and non-Newtonian flow regimes in a model pipe are presented, and results on calculated radial mass flux and wax deposition profiles as a function of time and position in a vertical pipeline are discussed in detail. The results are compared with predictions from a previous model developed by Svendsen (Svendsen, J. A. (1993). Mathematical modeling of wax deposition in oil pipeline systems. AIChE J. 39(8):1377-1388.) and with experimental flow data for a binary mixture reported by Cordoba and Schall (Cordoba A. J., Schall C. A. Application of a heat method to determine wax deposition in a hydrocarbon binary mixture. Fuel 2001 80:1285-1291). Good agreement in both cases is found.     

Rheological characterization of 4,4′-bis (diethylamino)benzophenone-functionalized polybutadienes with low and medium vinyl content

In this article a mechnical spectroscopic study of a series of low (?8%) and medium (? 70%) vinyl-content polybutadiences, some of them functionalized with 4,4′-bis(diethylamino)-benzophenone, is presented. Characterization of polymers with well-known structure by small-amplitude oscillatory shear flow enabled investigation of the effect of the vinyl content and functional groups on the rheological behavior of the samples in the linear viscoelastic region. The Doi–Edwards viscolastic model, without any adjustable parameter, proved to be adequate to describe the relationship between the macro/micro structure of the polymers and their viscoelastic properties. Results indicate that the vinyl content and functional groups modify the rheological behavior extensively. © 1995 John Wiley & Sons, Inc.     

On predicting self-diffusion coefficients from viscosity in gases and liquids

The relations between self-diffusion and viscosity for compressed liquids and gases have been reviewed, and a new equation for correlating viscosities over wide ranges of temperature and pressure is proposed. This formula is inspired by the Lennard-Jones Chain model of Yu and Gao for self-diffusion, and represents the viscosities of 15 compounds (1046 data points) with an average absolute deviation of 6.95%. Moreover, as the presented equation and the Yu-Gao model require the same fitting parameters, the ability to calculate self-diffusion coefficients from the viscosity parameter is studied. Some of the classic reviewed relations, such as the Stokes-Einstein formula, are also contrasted with the available experimental data of both transport properties.     

Physical and mathematical models of gas‐liquid fluid dynamics in LD converters

Fluid dynamics of gas‐liquid interactions in a LD converter to refine steel was physically and mathematically simulated. Using a water model three cases of gas supply were considered, top blowing, bottom injection and combined process top blowing‐bottom injection. Mixing time in top blowing increases with bath height and the distance between the lance of the gaseous jet and the bath surface. The jet penetration was found to be dependent on the modified Froude number. The unstable and unsteady behaviour of the bath topography, as affected by the gaseous jet, was well simulated through a multiphase momentum transfer model. In top blowing, three zones of liquid splashing were found, penetration with low splash, heavy splash and dimpling with low splash intensity. These zones depend on the gas flow rate and the distance from the lance to the bath surface. During bottom injection mixing times decrease with the number of tuyères, increases of bath height and gas flow rate. In a combined process mixing time decreases considerably due to the recirculating flow formed by the action of the top jet and the submerged jets. When a submerged jet is located just below the top jet the mixing time does not decrease as compared with the separated processes either top blowing or bottom stirring.     

Measurement and modeling of single- and multi-component adsorption equilibria of VOC on high-silica zeolites

From pure and binary gas adsorption equilibria measurements carried out using a volumetric method for three volatile organic compounds (methyl ethyl ketone, toluene (TOL), and 1,4-dioxane) on two high-silica zeolites, desaluminated faujasite Y (Fau Y) and ZSM-5 (Sil Z), co-adsorption was investigated and modeled. Apart from steric exclusion taking place with TOL-containing mixtures on Sil Z, micropore filling was similar to distillation since the component with the lower volatility adsorbed preferentially. At low coverage, chemisorption on specific sites happened in favor of polar or major compound, whereas at saturation the adsorbent was selective for the minor compound. Second, a quantitative prediction of binary equilibria was performed using the ideal adsorbed solution theory (IAST), examining the influence of pure component adsorption fitting model. The efficiency of correlations when extending AST to real mixture behavior was satisfactory in most cases. For engineering purposes, Fau Y is to be considered as a high-adsorption capacity adsorbent, whose selectivity can be described qualitatively by the distillation analogy and predicted quantitatively with the IAST in case of quasi-ideal mixtures.     

Influential factors on the outer lens color in an industrial injection molding process

The quality and the aspect of outer lens fabricated by an injection molding process are an essential part for the optical properties of vehicular lighting system. This work is accurately addressed to identify the influential factors on the red color of the outer lens made of blends of polycarbonate and acrylonitrile butadiene styrene, which are mixed with a red masterbatch. Seven factors were investigated in this work: masterbatch concentration, mold and nozzle temperatures, holding and packing pressures, and holding and packing times. The main influential factors were found through a design of experiments in a linear approximation. The outer lens's red color is mainly influenced by the masterbatch concentration, the nozzle temperature, holding time, and the holding pressure, in a decreasing order. In contrast, the mold temperature, packing pressure, and packing time are not statically significant in the color appearance.