Organic film distribution

Butt, C.M., Diamond, M.L., et al. (2004a) Spatial distribution of polybrominated diphenyl ethers in southern Ontario as measured in indoor and outdoor window organic films. Environmental Science and Technology, 38(3) 724—731. 

PROBING METAL DISTRIBUTIONS IN ORGANIC FILMS WITH X-RAY STANDING WAVES... 

Delcorte, A., Bertrand, P. (1996) Kinetic energy distributions of secondary molecular ions from thin organic films under ion bombardment. Nucl. Instrum. Meth. Phys. Res. B, 115,246-250. 

There are no "nozzles for an even SOj/air distribution over all pipes. The pressure drop over the 6 m pipe can be calculated with the well-known Fanning equation for turbulent flow. For an SOa/air velocity of 30 m/s in an empty reactor pipe a value of 0.025 bar is found. In experiments with air and organic film (without any sulphonation reaction) a pressure drop of 0.1 bar was measured at an air velocity of 30 m/s. The interaction of the air with liquid film ripples and waves causes an increase of about a factor 4 in the pressure drop compared with the empty tube. Under real sulphonation conditions the pressure drop measured becomes even greater at 0.25 bar, due to the sharp increase of viscosity at high conversions. 

The Ballestra Sulphurex CSTR system is relatively simple in its mechanical construction. The same can be said about the Chemithon Jet Impact Reactor. Film reactors are mechanically more sophisticated constructions, notably the organic liquid distribution systems. The delicate FFRs can not always be recommended for countries where the level of technology and maintenance is low. 

For purposes of reducing 1,4-dioxane, control of the mole ratio was found to be a much broader concept than simply ratioing reactants to the reactor. The mole ratio had to be controlled at all points in the reactor. This means that the organic films in the reactor have to be controlled so that they are of equal thickness (mass) at each circumferential cross-section of the reactor. The gas flow has to be controlled so that it is uniform at all points around the reactor circumference. In addition, the organic film has to be introduced into the reactor so that organic mist does not form. To accomplish this, Chemithon developed a new precise organic distribution system to ensure liquid film uniformity ( 0.5%) on the reactor surfaces. The reactor geometry provides the gas flow control required to ensure uniform SO3 gas supply to all points in the reactor. 

Seidl created a model based on the state of the surface film (e.g. expanded or condensed), the equilibrium spreading pressure, and the area per film molecule to describe organic film formation from fatty acids, then applied it to rainwater and aerosol particles [245]. He concluded that, in most cases, only dilute films (with concentrations below that necessary to form a complete monolayer) would form on aerosols and raindrops, and such films would not affect their physical or chemical properties. However, dense films were predicted to form on aerosols in the western U.S., mainly attributable to biomass burning. Mazurek and coworkers developed a model to describe structural parameters (elastic properties, etc.) of fatty acid films on rainwater without requiring knowledge of the surfactant concentration or composition by using surface pressure-area and surface pressure-temperature isochors and the rain rate and drop diameter distribution [33]. This model can be used to identify the origin of specific compounds and an approximate chemical composition based on the force-area characteristics of collected rainwater films. 

Corrosion that occurs under organic films in the form of randomly distributed thread-like filaments or spots. In many cases this is identical to filiform corrosion. 

Dukler Theory The preceding expressions for condensation are based on the classical Nusselt theoiy. It is generally known and conceded that the film coefficients for steam and organic vapors calculated by the Nusselt theory are conservatively low. Dukler [Chem. Eng. Prog., 55, 62 (1959)] developed equations for velocity and temperature distribution in thin films on vertical walls based on expressions of Deissler (NACA Tech. Notes 2129, 1950 2138, 1952 3145, 1959) for the eddy viscosity and thermal conductivity near the solid boundaiy. According to the Dukler theoiy, three fixed factors must be known to estabhsh the value of the average film coefficient the terminal Reynolds number, the Prandtl number of the condensed phase, and a dimensionless group defined as follows ... 

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