Absorption cross-flow

Plate column Cross-flow, countercurrent Integral Liquid and/or gas Absorption, rectification, stripping... 

Spray chamber Cocurrent, cross-flow, countercurrent Differential Gas Absorption, stripping, humidification, dehi i midi ficati o n... 

Cross-flow plates are the most common type of plate contactor used in distillation and absorption columns. In a cross-flow plate the liquid flows across the plate and the vapour... 

As is the case for LIF, calibration to obtain absolute concentrations is a challenge. In the instrument shown in Fig. 11.45, a calibration source based on the photolysis of water at 185 nm is installed in the inlet. From the absorption cross section of HzO gas at 185 nm, its concentration, the light intensity, and the sample flow rate, the concentration of OH generated by the photolysis can be calculated. However, not only is there significant uncertainty in the absorption cross section for HzO at 185 nm (e.g., see Lazendorf et al., 1997 Hofzumahaus et al., 1997, 1998 and Tanner et al., 1997), but the measured calibration factor was highly variable from day to day, by as much as a factor of two (Tanner et al., 1997). 

The mathematical reconstruction of a property field, F(x,y), from its projection in the 0 direction is the basis of "Computerized Tomography" (1,2). An identical technique can be used to reconstruct a field of linear absorption coefficient functions in a combusting flow field from multiangular path integrated absorption measurements. The linear absorption coefficient is the familiar N.Q. product, where is the concentration of species i and Q. is the absorption cross section of species i at the frequency v. The Bouguer-Lambert-Beer law states that... 

It has already been stated that a simple way to enhance the resolution of an FFF measurement is to reduce the channel thickness. This however can lead to other problems as the effects of surface irregularities are enhanced, due to the increase of the surface-to-volume ratio of the channel, and lead to increasing, unpredictable solute-wall interactions, etc. Furthermore, non-uniformities in the channel planarity will also be a problem with very small channel thicknesses, especially in Fl-FFF where the accumulation wall is a membrane. Another possibility for the reduction of H is to reduce the flow velocity of the carrier liquid which, in turn, leads to longer retention times and slower separation. However, in Fl-FFF, one has the possibility to increase the flow rate with cost to resolution but simultaneously increase also the cross-flow rate. Nevertheless, this enhances sample absorption onto the membrane. The third possibility for the reduction of H is to increase the solute diffusion. This can be done by decreasing the solvent viscosity by increasing the temperature. 

Chemiluminescence spectra of AlF(a n) produced in crossed-beam reaction of A1 with Fj t Tandem axis LMR/resonance fluorescence/resonance absorption fast-flow system used to study N + 0H,H02 and 0 + 0H,H02... 

Danckwerts P.V., Significance of liquid film coefficients in gas absorption. Industrial Engineering and Chemistry 43 1951 460-1470. Denisov C.A., Theory of concentration polarization in cross-flow ultrafiltration Cel-layer model and osmotic-pressure model. Journal of Membrane Science 91 1994 173-187. 

Cross-flow plates are the most common type of plate contactor used in distillation and absorption columns. In a cross-flow plate, the liquid flows across the plate and the vapor up through the plate. A typical layout is shown in Figure 11.19. The flowing liquid is transferred from plate to plate through vertical channels called downcomers. A pool of liquid is retained on the plate by an outlet weir. 

In the pneumatic nebulizers used in atomic spectrometry, the liquid flow is usually of the order of 1 to a few mL/min and the full efficiency of the nebulizer (a few %) can actually be realized at gas flows of 2 L/min. However, even with gas flows below 2 L/min, droplet diameters as low as about 10 pm and injection velocities below about 10 m/ s are obtained. Pneumatic nebulization can be realized with a number of types of nebulizers. For flame emission and atomic absorption as well as for plasma spectrometry, they include concentric nebulizers, so-called cross-flow nebulizers, Babington nebulizers and fritted-disk nebulizers (Fig. 40) [95]. 

Absorption can take place in a countercurrent, cocurrent, or cross-flow device. Vertical countercurrent towers are either built with a metal, plastic, or ceramic packing or constructed as plate towers with various types of plates. This chapter will discuss the solvents used to carry out absorption and the various types of absorption equipment. 

Some processes for both absorption and the removal of particulates employ a cross-flow spray... 

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