Interface liquid-particle

The experimental and theoretical work reported in the literature will be reviewed for each of the five major types of ga s-liquid-particle operation under the headings Mass transfer across gas-liquid interface mass transfer across liquid-solid interface holdup and axial dispersion of gas phase holdup and axial dispersion of liquid phase heat transfer reaction kinetics. 

Date for mass transfer across the liquid-solid interface are virtually nonexistent for packed-bed gas-liquid-particle operations. The smaller particle size that may be employed in suspended-bed operations should be an advantage in this respect, but the packed-bed operations have, on the other hand, the advantage of having higher possible relative velocities between liquid and solid. 

P. A. Kralchevsky and K. Nagayama Capillary Interactions Between Particles Bound to Interfaces, Liquid Films and Biomembranes. Adv. Colloid Interface Sci. 85, 145 (2000). 

Here, issues in relation to the trickle flow regime—isothermal operation and plug flow for the gas phase—will be dealt with. Also, it is assumed that the flowing liquid completely covers the outer surface particles (/w = 1 or aLS = au) so that the reaction can take place solely by the mass transfer of the reactant through the liquid-particle interface. Generally, the assumption of isothermal conditions and complete liquid coverage in trickle-bed processes is fully justified with the exception of very low liquid rates. Capillary forces normally draw the liquid into the pores of the particles. Therefore, the use of liquid-phase diffusivities is adequate in the evaluation of intraparticle mass transfer effects (effectiveness factors) (Smith, 1981). 

Solution. Let yLP, yLS. and ysp be the energies (per unit area) of the liquid/particle, liquid/solid, and solid/particle interfaces, respectively. From Section 19.2.1 the volume of the solid nucleus is Vs = (2 — 3 cos 6 + cos3 8), the spherical liquid/solid... 

FIGURE 17.8 Illustration of adsorption of a polymer at the solid-liquid interface, inhibiting particle agglomeration via a steric barrier, (a) Adsorbed polymer on the surface of two particles (b) interpenetration of the adsorbed layers as the particle surfaces approach is energetically unfavorable owing to osmotic and entropic phenomena. (Reprinted from Meyers, D. (19ffiljrfaces, Interfaces, and CollojctefCH Publishers, Inc.,... 

After total addition of 9mL water, resulting in the weight fractions u>il = 0.45, WaicIj = 0.16 and u>h2o = 0.39, the mixture was stirred for 15 min. Subsequently the sample was shaken for an additional 10 min while cooling to ambient conditions. At room temperature the mixture divided into two liquid phases. These phases were separated (Figure 11.19) by centrifugation (20 min at 2460 g). The lower clear and more viscous phase was presumed to be the IL phase and the upper liquid the water phase. At the interface fine particles were collected. 

Atomization is the process by which sprays are produced by converting a liquid into aerosolized liquid particles. The large increase in the liquid-air interface, together with the transportation of the drops, requires energy input. The forces governing the process of converting a liquid into aerosolized liquid particles are ... 

Hiac 2000 liquid particle counter provides an inexpensive means to transfer up to four channels of particle size information data from sensor to host computer system. Data can be viewed in real-time via a liquid erystal display. The 2000 interfaces to all Hiac liquid sensors including the MicroCount, submicron and HRLD laser sensors. Applications include point-of-use monitoring for corrosive chemieal delivery systems, DI water lines, wet process tools, hydraulic oil systems and parts cleaning... 

The many benefits of ultrasound in chemical systems are well-known, and are reported elsewhere in this volume, but perhaps the most striking influence of ultrasound concerns heterogeneous reaction systems, particularly those with a solid-liquid interface where particle size modification, the cleaning of surfaces, or the formation of fresh surfaces are among the beneficial processes. 

Most processes of powder wetting operate under dynamic conditions, and improvements in their efficiency require the use of surfactants that lower the liquid surface tension Yiy under these circumstances. The interfaces involved (particles separated from aggregates or agglomerates) are freshly formed and have only a small effective age of some seconds, or even less than a millisecond. 

The authors have also applied the method of molecular dynamics (see Chapter III,4) for the investigation of peculiarities in the formation and rupture of coagulation contacts at the atomic-molecular level [29], It was established that at the nano-level under the conditions of a complete lyophilicity (macroscopically, at extremely low interfacial tension at solid-liquid interface) the particle did not always readily separate from the substarate, because its separation required that a particular gap was to be formed before the dispersion medium could penetrate underneath the particle and fill this gap. This means that molecular attractive forces had to be mostly overcome before the work of wetting could be performed, which required either the work of external forces or waiting for a long period of time for a suitable fluctuation. Periodic oscillations of force, experimentally observed by J. Israelachvili [30], were also present at several molecular distances. 

C. Korber, Phenomena at the advancing ice-liquid interface solutes, particles and biological cells. Quart. Rev. Biophys., 1988, 21, 229-298. 

Thermospray and, more recently, electrospray ionization have found wide application as an interface technology between HPLC instruments and mass spectrometers. They represent powerful techniques for the analysis of complex lipids directly from solutions (Henion and Lee, 1990 Murphy, 1993). In most instances, the total HPLC eluant can be sent directly into the heated thermospray ion source. Here, the combination of heat and eluant velocity creates a plume of small-diameter particles suspended in a vapor (nebulization). A strong electric charge forms on the surface of the liquid particles and as the droplets evaporate the increase in charge ionizes analyte molecules that are discharged directly from the droplet into the gas phase. From here, they may enter the mass spectrometer directly. 

In this chapter, the fundamental aspects of (I) liquid-liquid electroosmotic flow and (If) liquid-particle electrophoretic flow considering the free charge at the interface are studied to investigate the characteristics of such two-phase flow system. 

In general, it is also possible in a slurry reactor that a significant mass transfer resistance 1/kgag can be observed at liquid-particle interface. However, due to the small catalyst particles which are usually applied in the FT slurry process the interfacial area a is large, ag is given by... 

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