pinecone/core-2020-05-10-deduplication huggingface dataset:
Kinetic study of 1-butanol dehydration to di-n-butyl ether over Amberlyst 70

Kinetics of the catalytic dehydration of 1-butanol to di-n-butyl ether (DNBE) over Amberlyst 70 was investigated. Experiments were performed in liquid phase at 4 MPa and 413 463 K. Three elementary reaction mechanisms were considered: a Langmuir‐Hinselwood‐ Hougen‐Watson (LHHW) formulation; an Eley-Rideal (ER) formulation in which DNBE remains adsorbed; an ER formulation in which water remains adsorbed. Two kinetic models explain satisfactorily the dehydration of 1-butanol to DNBE: a LHHW formalism in which the surface reaction between two adjacent adsorbed molecules of 1-butanol is the rate limiting step (RLS) and where the adsorption of water is negligible, and a mechanism in which the RLS is the desorption of water being the adsorption of DNBE negligible. In both models the strong inhibiting effect of water was successfully taken into account by means of a correction factor derived from a Freundlich adsorption isotherm. Both models present similar values of apparent activation energies (122±2 kJ/mol
A New Dynamic Model of Crude Oil Fouling Deposits and Its Application to the Simulation of Fouling-Cleaning Cycles

Modelling of crude oil fouling in heat exchangers has been traditionally limited to a description of the deposit as a thermal resistance. However, consideration of the local change in thickness and the evolution of the properties of the deposit due to ageing or changes in foulant composition is important to capture the thermal and hydraulic impact of fouling. A dynamic, distributed, first-principles model of the deposit is presented that considers it as a multicomponent varying-thickness solid undergoing multiple reactions. For the first time, full cleaning, partial cleaning, and fouling resumption after cleaning can be simulated in any order with a single deposit model. The new model, implemented within a single tube framework, is demonstrated in a case study where various cleaning actions are applied following a period of organic deposition. It is shown that complete mechanical cleaning and chemical cleaning of different extent, according to a condition-based efficacy, can be seamlessly simulated
Impact of ownership structure along the value chain in the manufacturing business

In the chemical and petrochemical industry, it is quite common that the manufacturing of a final product is the result of
several consecutive steps which can be owned and operated by one or many participants. Although not always practical,
equal ownership among all partners along the value chain is often recommended as a way to simplify business structure,
ensuring all partners share equally in the ups and downs of an uncertain market. In contrast to this approach,
there are instances where more benefit can be derived from having different owners and operators along the value
chain. Examples which are common practice in the industry are the supply of utilities (e.g., electricity), feedstock, and
services. In these cases, the nonintegrated approach offers value as: It provides the operator of the upstream or utility
plants the opportunity to specialize, for example, by operating very similar plants around the world. Such specialization
enables the use of regional operating centers, minimum onsite cash costs, optimized operating conditions, minimized
energy consumption, and the optimal use of other variable cost parameters. This article shows that if outsourcing results
in a cash cost saving by an upstream operator, the benefit to the downstream owner will (in financial reward) be proportional
to the cash cost saving achieved. In absolute terms, the magnitude of the benefit is moderated by the size of
the downstream capital investment (The bigger the downstream investment relative to the upstream investment, the
smaller the impact of the saving on the economics of the downstream company). As a “utility provider” an upstream
operator benefits from lower risk in terms of offtake and market price uncertainties. Such owners benefit from a lower
cost of capital, and as such also have lower return expectations than players further along in the value chain (who are
exposed to all the uncertainties in volatile markets). This article shows that the positive impact of such benefits to the
return of the downstream partner is directly proportional the difference in return expectations between the upstream
and downstream company. Once again, the absolute magnitude of the saving becomes more substantial as the ratio of
upstream capital investment increases relative to the downstream capital investment. Economy of learning may also enable
a specialized upstream company to obtain an asset at a lower capital than a less specialized downstream operator.
This article shows that the positive impact of such a benefit is very similar to that of a lower return expectation by the
upstream company.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1547-59052017-04-30hb2016Chemical Engineerin
Characterization of extensional rheological filament stretching with a dual-mode Giesekus model

A new, simple, formulation that describes capillary thinning as predicted by a two-mode Giesekus model is derived, and its application in analysing data from extensional rheometry (capillary thinning) experiments is discussed. An algorithm is presented that can be used to fit the expressions obtained from the Giesekus model to extensional rheometry data. Examples of data fitting are given for an idealised data set, for measurements obtained for aqueous solutions of 6 wt% 900,000 molecular weight polyethylene oxide, and for biological fluids obtained from pitchers of Nepenthes Rafflesiana. Good fits to the data were obtained, with coefficients of determination in excess of 0.98. For each data set, it was possible to calculate values of extensional viscosity and relaxation time for each of the two modes, allowing quantitative comparison of different fluids or of the same fluid as it ages.The authors are grateful to Dr Ulrike Bauer, University of Bristol, for access to experimental data on pitcher plant fluids obtained in the field in Brunei Darussalam between August and September 2014. The authors wish to acknowledge Edward Bosson and Tom Hoier for their data analysis of pitcher plant fluids that identified the initial region of filament thinning, colloquially termed the ‘hockey stick’.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/aic.1518
Strain Mode of General Flow: Characterization and Implications for Flow
  Pattern Structures

Understanding the mixing capability of mixing devices based on their
geometric shape is an important issue both for predicting mixing processes and
for designing new mixers. The flow patterns in mixers are directly connected
with the modes of the local strain rate, which is generally a combination of
elongational flow and planar shear flow. We develop a measure to characterize
the modes of the strain rate for general flow occurring in mixers. The spatial
distribution of the volumetric strain rate (or non-planar strain rate) in
connection with the flow pattern plays an essential role in understanding
distributive mixing. With our measure, flows with different types of screw
elements in a twin-screw extruder are numerically analyzed. The difference in
flow pattern structure between conveying screws and kneading disks is
successfully characterized by the distribution of the volumetric strain rate.
The results suggest that the distribution of the strain rate mode offers an
essential and convenient way for characterization of the relation between flow
pattern structure and the mixer geometry
Heterogeneous fenton and photo-fenton oxidation for paracetamol removal using iron containing ZSM-5 zeolite as catalyst

Paracetamol is commonly found in wastewaters, as a consequence of its high consumption and incomplete elimination by conventional treatments. Homogenous (photo-)fenton oxidation has proved efficient for its remediation, but it suffers from uneasy dissolved iron recovery. Therefore this work examines the performance and stability of an iron containing zeolite (Fe/MFI) as catalyst for this reaction. Effects of reaction parameters (pH, temperature, catalyst and H2O2 concentrations, UV/vis irradiation) are investigated in batch conditions, by comparing the pollutant and total organic carbon disappearance rates in solution, as well as the overall mineralization yield (including solid phase) and oxidant consumption. At near neutral pH paracetamol can be fully converted after 5 h, while TOC removal reaches up to 60%.\ud
Finally, thanks to good catalyst stability (low leaching), a continuous process coupling oxidation and membrane filtration is proposed, showing constant TOC conversion over 40 h and iron loss in the permeate <0.3 ppm
Catalytic membrane reactor for Suzuki-Miyaura C-C cross-coupling: Explanation for its high efficiency via modeling

A polymeric catalytic membrane was previously prepared that showed remarkable efficiency for Suzuki-Miyaura C-C cross-coupling in a flow-through configuration. A mathematic model was developed and fitted to the experimental data to understand the significant apparent reaction rate increase exhibited by the catalytic membrane reactor compared to the catalytic system under batch reaction conditions. It appears that the high palladium nanoparticles concentration inside the membrane is mainly responsible for the high apparent reaction rate achieved. In addition the best performance of the catalytic membrane could be achieved only in the forced flow-through configuration, that, conditions permitting to the reactants be brought to the catalytic membrane by convection
Designing an Artificial Golgi Reactor to achieve targeted glycosylation of monoclonal antibodies

The therapeutic efficacy of monoclonal antibodies (mAbs) is dependent upon their glycosylation patterns. As the largest group of currently approved biopharmaceuticals, the microheterogeneity in mAb oligosaccharide profiles deriving from mammalian cell production is a challenge to the biopharmaceutical industry. Disengaging the glycosylation process from the cell may offer significant enhancement of product quality and allow better control and reproducibility in line with the Quality by Design paradigm. Three potential designs of an Artificial Golgi reactor implementing targeted sequential glycosylation of mAbs are proposed including a (i) microcapillary film reactor, (ii) packed bed reactor with non-porous pellets, and (iii) packed bed reactor with porous pellets. Detailed mathematical models are developed to predict their performance for a range of design and operational parameters. While all three reactor designs can achieve desired conversion levels, the choice of a particular one depends on the required throughput and the associated cost of enzymes and co-substrates
Outer approximation algorithm with physical domain reduction for computer-aided molecular and separation process design

Integrated approaches to the design of separation systems based on computer-aided molecular and process design (CAMPD) can yield an optimal solvent structure and process conditions. The underlying design problem, however, is a challenging mixed integer nonlinear problem, prone to convergence failure as a result of the strong and nonlinear interactions between solvent and process. To facilitate the solution of this problem, a modified outer-approximation (OA) algorithm is proposed. Tests that remove infeasible regions from both the process and molecular domains are embedded within the OA framework. Four tests are developed to remove subdomains where constraints on phase behavior that are implicit in process models or explicit process (design) constraints are violated. The algorithm is applied to three case studies relating to the separation of methane and carbon dioxide at high pressure. The process model is highly nonlinear, and includes mass and energy balances as well as phase equilibrium relations and physical property models based on a group-contribution version of the statistical associating fluid theory (SAFT-γ Mie) and on the GC+ group contribution method for some pure component properties. A fully automated implementation of the proposed approach is found to converge successfully to a local solution in 30 problem instances. The results highlight the extent to which optimal solvent and process conditions are interrelated and dependent on process specifications and constraints. The robustness of the CAMPD algorithm makes it possible to adopt higher-fidelity nonlinear models in molecular and process design
Characterization of liquid-liquid flows in horizontal pipes

Diverse flow regimes have been encountered in liquid-liquid flows. Some degree of consistency in the observed flow patterns is shown in reported studies, while inconsistency exits when physical properties of the two phases concerned are wide enough. An attempt was made in this study to investigate the mechanisms behind flow patterns of liquid-liquid flows in horizontal pipes. A literature review on flow patterns of liquid-liquid flows in horizontal pipes was conducted. The ratio of the gravitational force to viscous force was proposed to characterize liquid-liquid flows in horizontal pipes into gravitational force dominant, viscous force dominant and gravitational force and viscous force comparable flow featured with different basic flow regimes. Comparisons of the proposed characterization criterion with the literature data show good agreement
Scaling of continuous twin screw wet granulation

Scaling rules were developed and tested for a continuous twin screw wet granulation process using three scales (11, 16, and 24 mm barrel diameter) of twin screw granulators (TSG). The distributive feed screw configuration used produced high porosity granules (50-60%) with broad bimodal size distributions, especially in the 16 and 24 mm TSGs. Three dimensionless numbers, Froude number (Fr), liquid-to-solid ratio (LSR), and powder feed number (PFN), were identified and their effect on granule size distribution (GSD), porosity and liquid distribution tested. Granule size increased with increasing LSR as expected. However, Fr and PFN had no significant effect on d10 or d50 and only a small effect on d90. In contrast, granulator scale had a strong effect on GSD, with d90 increasing almost linearly with barrel diameter. This is consistent with breakage of large granules being a dominant mechanism and directly controlled by the geometry of the screw
Mathematical modelling and experimental validation of a novel periodic flow crystallization using MSMPR crystallizers

This is the peer reviewed version of the following article: SU, Q. ...et al., 2016. Mathematical modelling and experimental validation of a novel periodic flow crystallization using MSMPR crystallizers. AIChE Journal, 63 (4), pp. 1313–1327., which has been published in final form at http://dx.doi.org/10.1002/aic.15510. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.The challenges of insufficient residence time for crystal growing and transfer line blockage in conventional continuous MSMPR operations are still not well addressed. Periodic flow crystallization is a novel method whereby controlled periodic disruptions are applied to the inlet and outlet flows of an MSMPR crystallizer in order to increase its residence time. A dynamic model of residence time distribution in an MSMPR crystallizer was first developed to demonstrate the periodic flow operation. Besides, process models of periodic flow crystallizations were developed with an aim to provide a better understanding and improve the performance of the periodic flow operation, wherein the crystallization mechanisms and kinetics of the glycine-water system were estimated from batch cooling crystallization experiments. Experiments of periodic flow crystallizations were also conducted in single- / three-stage MSMPR crystallizers to validate the process models and demonstrate the advantages of using periodic flow operation in MSMPR stages
Optical methods to investigate the enhancement factor of an oxygen-sensitive colorimetric reaction using microreactors

Visualization of mass transfer is a powerful tool to improve understanding of local phenomenon. The use of an oxygen-sensitive dye (colorimetric technique1) has showed its relevancy for locally visualizing and characterizing gas-liquid mass transfer at different scales2,3. At present, the occurrence of a possible enhancement of the gas-liquid mass transfer by this reaction has not been yet demonstrated. This paper aims at filling this gap by evaluating the Hatta number Ha and the enhancement factor E associated with the oxygen colorimetric reaction when implementing in milli/micro channels. For that, as data on the kinetic of the colorimetric reaction are seldom in the literature, the reaction characteristic time was firstly estimated by carrying out experiments in a microchannel equipped with a micromixer. The diffusion coefficients of dihydroresorufin and O2 were then determined by implementing two original optical methods in a specific coflow microchannel device, coupled with theoretical modelling. The knowledge of these parameters enabled at last to demonstrate that no enhancement of the gas-liquid mass transfer by this colorimetric reaction existed. Complementary information about the reliability of the colorimetric technique to characterize the gas-liquid mass transfer in milli/micro systems was also give
Experimental Investigation of Interfacial Mass Transfer Mechanisms for a Confined High-Reynolds-Number Bubble Rising in a Thin Gap

Interfacial mass transfer is known to be enhanced for confined bubbles due to the efficiency of the transfer in the thin liquid films between them and the wall. In the present experimental investigation, the mechanisms of gas–liquid mass transfer are studied for isolated bubbles rising at high Reynolds number in a thin gap. A planar laser induced fluores- cence (PLIF) technique is applied with a dye the fluorescence of which is quenched by dissolved oxygen. The aim is to measure the interfacial mass fluxes for pure oxygen bubbles of various shapes and paths rising in water at rest. In the wakes of the bubbles, patterns due to the presence of dissolved oxygen are observed on PLIF images. They reveal the contrasted contributions to mass transfer of two different regions of the interface. The flow around a bubble consists of both two thin liquid films between the bubble and the walls of the cell and an external high-Reynolds-number in-plane flow surrounding the bubble. Mass transfer mechanisms associated to both regions are discussed. Measurement of the concentration of dissolved oxygen is a difficult task due to the nonlinear relation between the fluorescence intensity and the concentration in the gap. It is however possible to accurately measure the global mass flux transferred through the bubble interface. It is determined from the fluorescence intensity recorded in the wakes when the oxygen distribution has been made homogeneous through the gap by diffusion. Assuming a reasonable distribution of oxygen concentration through the gap at short time also allows a measurement of the mass fluxes due to the liquid films. A discussion of the results points out the specific physics of mass transfer for bubbles confined between two plates as compared to bubbles free to move in unconfined flows. VC 2016 American Institute of Chemical Engineers AIChE J, 63: 2394–2408, 201
Group additive modeling of substituent effects in monocyclic aromatic hydrocarbon radicals

The thermodynamic properties of the unsubstituted and substituted phenyl, phenoxy, anisyl, benzoyl, styryl and benzyl radicals with six substituents (hydroxy, methoxy, formyl, vinyl, methyl, and ethyl) are calculated with the bond additivity corrected (BAC) post-Hartree-Fock G4 method. Bond dissociation energies of monocyclic aromatic hydrocarbons are calculated and used to identify substituent interactions in these radicals. Benson's Group Additivity (GA) scheme is extended to aromatic radicals by defining 6 GAV and 29 NNI parameters through least squares regression to a database of thermodynamic properties of 369 radicals. Comparison between G4/BAC and GA calculated thermodynamic values shows that the standard enthalpies of formation generally agree within 4 kJ mol−1, whereas the entropies and the heat capacities deviate less than 4 J mol−1 K−1
Absorption methods for the determination of mass transfer parameters of packing internals: A literature review

Methods for the determination of mass‐transfer coefficients and effective interfacial areas in packed absorption columns are reviewed. For each parameter, the methods are grouped into categories on the basis of their physical principle; the chemical systems used, experimental protocol, and the advantages and inconveniences are discussed. The treatment of end effects, the influence of packed bed height, and the recent efforts in standardization of measurement methods are also treated. The aim of the review is to give a broad overview of the methods used in literature in the last eight decades, some of which might be reconsidered in the light of modern measurement techniques and to evaluate them in relation to precision, practicality and hazardousness thereby to facilitate the search for reliable, precise, and convenient experimental practices
Modeling the Dynamics of Tamponade Multicomponent Gases During Retina Reattachment Surgery

Vitrectomy and pneumatic retinopexy are common surgical procedures used to treat retinal detachment. To reattach the retina, gases are used to inflate the vitreous space allowing the retina to attach by surface tension and buoyancy forces that are superior to the location of the bubble. These procedures require the injection of either a pure tamponade gas, such as C3F8 or SF6, or mixtures of these gases with air. The location of the retinal detachment, the anatomical spread of the retinal defect, and the length of time the defect has persisted, will determine the suggested volume and duration of the gas bubble to allow reattachment. After inflation, the gases are slowly absorbed by the blood allowing the vitreous to be refilled by aqueous. We have developed a model of the mass transfer dynamics of tamponade gases during pneumatic retinopexy or pars plana vitrectomy procedures. The model predicts the expansion and persistence of intraocular gases (C3F8, SF6), oxygen, nitrogen, and carbon dioxide, as well as the intraocular pressure. The model was validated using published literature in rabbits and humans. In addition to correlating the mass transfer dynamics by surface area, permeability, and partial pressure driving forces, the mass transfer dynamics are affected by the percentage of the tamponade gases. Rates were also correlated with the physical properties of the tamponade and blood gases. The model gave accurate predictions in humans
Morphological properties of flocs under turbulent break-up and restructuring processes

Bentonite flocculation was performed in a Taylor–Couette reactor coupled with an in situ method of image acquisition and analysis. A hydrodynamic sequencing is imposed to perform successive cycles of flocculation and breakage. Depending on the shear rate applied during the breakage step, one or two cycles are needed after the first flocculation step to recover a full reversibility on both size and shape factors. The breakup step produces flocculi that are the building blocks for the next. The re‐flocculation steps produce smaller sizes and more regular shapes than the initial growth step. The floc size is calibrated by the turbulence as the radius of gyration is close to the Kolmogorov microscale whereas the floc structure is determined by flocculi aggregates. An analysis of the change of the flocs morphology, despite of their diversity, can also be achieved thanks to some relevant moments of the distributions