Dispersant gases

Extra coarse 170-220 Filtration of very coarse materials. Gas dispersion, gas washing, and extractor beds. Support of other filter materials. 

Most new designs of cross-flow plates employ perforations for dispersing gas into hquid on the plate. These perforations may be simple... 

Practical separation techniques for gases dispersed in liquids are discussed. Processes and methods for dispersing gas in hquid have been discussed earlier in this section, together with information for predicting the bubble size produced. Gas-in-hquid dispersions are also produced in chemical reactions and elec trochemic cells in which a gas is liberated. Such dispersions are likely to be much finer than those produced by the dispersion of a gas. Dispersions may also be uninten-tionaUy created in the vaporization of a hquid. 

Hieks, R. W. and L.E. Gates, How to Seleet Turbine Agitators for Dispersing Gas into Liquids, Chem. Engr., July 19, 1996, pp 141-148. 

In addition, they are usually constructed without isolation valves on the fuel supply lines. As a result the final connection in the pipework cannot be leak-tested. In practice, it is tested as far as possible at the manufacturer s works but often not leak-tested on-site. Reference 32 reviews the fuel leaks that have occurred, including a major explosion at a CCGT plant in England in 1996 due to the explosion of a leak of naphtha from a pipe joint. One man was seriously injured, and a 600-m chamber was lifted off its foundations. The reference also reviews the precautions that should be taken. They include. selecting a site where noise reduction is not required or can be achieved w ithout enclosure. If enclosure is essential, then a high ventilation rate is needed it is often designed to keep the turbine cool and is far too low to disperse gas leaks. Care must be taken to avoid stagnant pockets. 

Grassman (G7) has proposed a simplified theoretical treatment of heat and mass transfer between two fluid phases, as, for example between a dispersed gas phase and a continuous liquid phase von Bogdandy et al. (V8) measured the rate of absorption of carbon dioxide by water and by decalin, and found that the absorption rate approximated that predicted by Grass-mann in the laminar region but was above the theoretical values in the... 

Mass transfer across the liquid-solid interface in mechanically agitated liquids containing suspended solid particles has been the subject of much research, and the data obtained for these systems are probably to some extent applicable to systems containing, in addition, a dispersed gas phase. Liquid-solid mass transfer in such systems has apparently not been studied separately. Recently published studies include papers by Calderbank and Jones (C3), Barker and Treybal (B5), Harriott (H4), and Marangozis and Johnson (M3, M4). Satterfield and Sherwood (S2) have reviewed this subject with specific reference to applications in slurry-reactor analysis and design. 

The expression gas-liquid fluidization, as defined in Section III,B,3, is used for operations in which momentum is transferred to suspended solid particles by cocurrent gas and liquid flow. It may be noted that the expression gas-liquid-solid fluidization has been used for bubble-column slurry reactors (K3) with zero net liquid flow (of the type described in Sections III,B,1 and 1II,V,C). The expression gas-liquid fluidization has also been used for dispersed gas-liquid systems with no solid particles present. 

Thrust, 4 Trickle-flow, 79 fixed-bed, 90-104 holdup and axial dispersion gas phase, 92-94 liquid phase, 94-102... 

An agitated tank with a standard Rushton impeller is required to disperse gas in a solution of properties similar to those of water. The tank will be 3 m diameter (1 m diameter impeller), A power level of 0.8 kW/m3 is chosen. Assuming fully turbnlent conditions and feat the presence of fee gas does not significantly affect the relation between fee Power and Reynolds numbers ... 

Distributing a dispersed gas in a continuous liquid is very difficult, while spraying a liquid into a gas is more easily done. The inertia on the drops allows them to move over a wide area. The limitation is the reaction time in relation to the settling time. 

Absorption with multiple contact washing by dispersing gas into fine bubbles of large surface... 

The Eulerian multiphase model is used to predict the dispersed gas-liquid flow in the airlift loop reactor. It involves a set of momentum and continuity equations for each phase. Model equation coupling is achieved through the pressure and interphase exchange coefBcdents [5],... 

An Eulerian-Eulerian (EE) approach was adopted to simulate the dispersed gas-liquid flow. The EE approach treats both the primary liquid phase and the dispersed gas phase as interpenetrating continua, and solves a set of Navier-Stokes equations for each phase. Velocity inlet and outlet boundary conditions were employed in the liquid phase, whilst the gas phase conditions consisted of a velocity inlet and pressure outlet. Turbulence within the system was account for with the Standard k-e model, implemented on a per-phase basis, similar to the recent work of Bertola et. al.[4]. A more detailed description of the computational setup of the EE method can be found in Pareek et. al.[5]. 

HICKS, R. W. (1976) Chem, Eng., NY 83 (July 19th) 141. How to select turbine agitators for dispersing gas into liquids. 

Figure 10. Foam viscosity depends on percent internally dispersed gas (Mitchell quality). (Reproduced from ref. 363. U.S. Patent 3 937 283,1976.)...

Frohlich, S., Lotz, M., Larson, B., Lilbbert, A., Schilgerl, K., Seekamp, M., Characterization of a Pilot Plant Airlift Tower Loop Bioreactor III. Evaluation of Local Properties of the Dispersed Gas Phase During Yeast Cultivation and in a Model Media, Biotechnol. Bioeng., 38 56 (1991b)... 

The selection of the appropriate dispersion model in an accidental release scenario requires the behavior of dispersing gas to be known since each model is specialized on one kind of release (buoyancy or gravity driven). 

Liquid-phase mass transfer coefficient Gas-liquid interfacial area per unit volume of dispersion Gas volume fraction in dispersion Diffusivity of cyanogen in solution Henry law coefficient... 

It can be assumed that this is caused by a kind of plasticizing of the polymer by dissolved or finely dispersed gas or by the increased solubility of the reaction products in the gases. 

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