Liquids volumetric

K a Overall volumetric liquid-pbase mass-transfer coefficient kmoP[(s-m )(mole-fraction (lbmol)/[(h-tt )(mole-traction... 

Reentrainment is generally reduced by lower inlet gas velocities. Calvert (R-12) reviewed the hterature on predicting the onset of entrainment and found that of Chien and Ibele (ASME Pap. 62-WA170) to be the most reliable. Calvert applies their correlation to a liquid Reynolds number on the wall of the cyclone, Nrcl = 4QilhjVi, where is the volumetric liquid flow rate, cmVs hj is the cyclone inlet height, cm and Vi is the Idnematic liquid viscosity, cmVs. He finds that the onset of entrainmeut occurs at a cyclone inlet gas velocity V i, m/s, in accordance with the relationship in = 6.516 — 0.2865 lu A Re,L ... 

Use is made of the Francis formula (equation 6.43). where, as in the previous example, n — 0. In the context of this example the height of liquid flowing over the weir is usually designated hmv and the volumetric liquid flow by Q. Rearrangement of equation 6.43 gives ... 

Lp = the volumetric liquid flow rate across the plate, divided by the average width of the plate, m3/sm. The average width can be calculated by dividing the active area by the length of the liquid path Zi,... 

The power input from a liquid stream injected with a hydraulic spray nozzle may usually be taken as approximately equal to the product of the nozzle feed pressure pF and die volumetric liquid rate. The liquid-phase contacting power PL may then be calculated from the following formulas ... 

Volumetric liquid rate per unit cross-sectional area of column Packing surface area per unit volume of column L uL... 

Thus the wetting rate is analogous to the volumetric liquid rate per unit length of circumference in a wetted-wall column in which the liquid flows down the surface of a cylinder. If the liquid rate were too low, a continuous liquid film would not be formed around the circumference of the cylinder and some of the area would be ineffective. 

Volumetric liquid holdups in the reflux drum and column base are held perfectly constant by changing the flow rates of bottoms product B and liquid distillate product. ... 

The influence of pressure on the mass transfer in a countercurrent packed column has been scarcely investigated to date. The only systematic experimental work has been made by the Research Group of the INSA Lyon (F) with Professor M. Otterbein el al. These authors [8, 9] studied the influence of the total pressure (up to 15 bar) on the gas-liquid interfacial area, a, and on the volumetric mass-transfer coefficient in the liquid phase, kia, in a countercurrent packed column. The method of gas-liquid absorption with chemical reaction was applied with different chemical systems. The results showed the increase of the interfacial area with increasing pressure, at constant gas-and liquid velocities. The same trend was observed for the variation of the volumetric liquid mass-transfer coefficient. The effect of pressure on kia was probably due to the influence of pressure on the interfacial area, a. In fact, by observing the ratio, kia/a, it can be seen that the liquid-side mass-transfer coefficient, kL, is independent of pressure. 

Volumetric liquid flow rate, gal/min. Volumetric liquid flow rate, bbls/day Kilo Btu/hr, at heat transfer equipment Enthalpy, Btu/lb... 

Thermal volumetric Liquids only 1 Measures time taken for liquid to flow between two detectors by means of a heat pulse High pressure liquid phase chromatography (Section 6.8.3 and Volume 2, Chapter 19) No moving parts. Suitable for high pressures and temperatures... 

FIG. 14-126 Predicted spray-tower cut diameter as a function of sprayed length and spray droplet size for (a) vertical-countercurrent towers and (b) horizontal-cross-flow towers per Calvert [J. Air Pollut. Control Assoc., 24, 929 (1974)]. Curve 1 is for 200-lJn spray droplets, curve 2 for 500-lJn spray, and curve 3 for 1000-pm spray. QdQc is the volumetric liquid-to-gas ratio, L liquid/m3 gas, and uG is the superficial gas velocity in the tower. To convert liters per cubic meter to cubic feet per cubic foot, multiply by 10 3. 

The volumetric liquid holdup, 4>L, depends on the gas/vapor and liquid flows and is calculated via empirical correlations (e.g., Ref. 65). For the determination of axial temperature profiles, differential energy balances are formulated, including the product of the liquid molar holdup and the specific enthalpy as energy capacity. The energy balances written for continuous systems are as follows ... 

For absorption controlled by diffusion through a gas film, it is necessary to provide a large enough interface area the interface area depends on the liquid to gas flow rate ratio, VL/VG, essentially for a defined dispersity of the absorbent. On the other hand, increasing VJV,c must lead to increased power consumption so it is important to optimize the flow rate ratio.. The experimental results on the influence of VL/VG on the sulfur-removal efficiency are shown in Fig. 7.13. To keep the conditions of atomization essentially the same, all the experiments in this set were carried out at a fixed volumetric liquid flow rate, VL while the gas flow rate, VG, for each run varies according to the required liquid to gas flow rate ratio and, simultaneously, the corresponding concentration of Ca(OH)2 was used to keep the ratio of Ca/S the same as 1.4. 

As an alternative to trays, especially at low volumetric liquid-to-vapor ratios, packing can be used to promote vapor-liquid contact. One approach is to dump specially shaped pieces of metal, glass, or ceramic material into the column, wherein they are supported on a grid. An example of dumped or random packing is shown in Fig. 7. 

Estimate a volumetric liquid flow rate as representative for operation. 

The downcomer aeration factor < tdc is defined by Eq. (6.18). It describes the fractional volumetric liquid holdup in the downcomer. 

The Volumetric Liquid-Side Mass Transfer Coefficient at the Gas-Liquid Interface... 

Abstract—Gas-liquid interfacial areas a and volumetric liquid-side mass-transfer coefficients kLa are experimentally determined in a high pressure trickle-bed reactor up to 3.2 MPa. Fast and slow absorption of carbon dioxide in aqueous and organic diethanolamine solutions are employed as model reactions for the evaluation of a and kLa at high pressure, and various liquid viscosities and packing characteristics. A simple model to estimate a and kLa for the low interaction regime in high pressure trickle-bed reactors is proposed. 

Gas-liquid mass transfer can have a strong effect on TBR overall performance therefore its accurate evaluation is essential for achieving successful design and scale-up. In spite of the vast information available on gas-liquid mass transfer characteristics of atmospheric TBRs [1,2] only a few researchers have studied how interfacial areas, a, and volumetric liquid-side mass transfer coefficients, kLa, evolve at elevated pressures. For example, it has been reported that both a and kLa increase as gas density is rised while the gas superficial velocity is kept constant [3-5], Similar observations regarding gas hold-up and two-phase pressure drop, as well as the delay in the onset of pulsing have also been reported [6],... 

VOLUMETRIC LIQUID-SIDE MASS TRANSFER COEFFICIENT... 

Gas-liquid interfacial areas, a, and volumetric liquid-side mass transfer coefficients, kLa, are measured in a high pressure trickle-bed reactor. Increase of a and kLa with pressure is explained by the formation of tiny bubbles in the trickling liquid film. By applying Taylor s theory, a model relating the increase in a with the increase in gas hold-up, is developed. The model accounts satisfactorily for the available experimental data. To estimate kLa, contribution due to bubbles in the liquid film has to be added to the corresponding value measured at atmospheric pressure. The mass transfer coefficient from the bubbles to the liquid is calculated as if the bubbles were in a stagnant medium. 

The correctness of the above hydrodynamic model of a polyhedral foam with border hydroconductivity and constant radius of border curvature can be confirmed by comparing the velocity Q calculated from Eqs. (5.9) and (5.11) with the volumetric liquid rate obtained by Krotov s theory [7]. Thus, the liquid flow under gravity at r = const is... 

Let us consider the results from gravitational flow, i.e. at identical reduced pressure at either external side of the porous plates (Api = Ap2 = const). It is assumed that the acceleration due to gravity can be neglected (Ap pgH). At complete tangential immobility of border surfaces, the volumetric liquid flow rate through the foam is given by Eq. (5.9) or (5.11). 

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