Souders equation

A more accurate value can be obtained if reliable values of density are available, or can be estimated with sufficient accuracy, from Souders equation, Souders (1938) ... 

Table 8.1. Contributions for calculating the viscosity constant I in Souders equation...

Diameter of Bubble Towers. It is evident from the foregoing that no simple method of establishing the diameter of a fractionator is possible. Perhaps the maximum in simplification is tfie preparation of charts similar to Fig. 16-11 or 16-12 for the situation at hand, or for a number of common situations. Nevertheless, some rapid means of approximation is useful, so the familiar Brown and Souders equation (16-8) will be used. This equation was originally based on entrainment, but some doubt has arisen regarding its relationship to entrainment. The equation was also related to surface tension of the liquid, and this concept has also been discredited.Finally, everyone agrees that the K constants... 

The term in equation 42 is called a Souders-Brown capacity parameter and is based on the tendency of the upflowing vapor to entrain Hquid with it to the plate above. The term E in equation 43 is called an E-factor. and E to be meaningful the cross-sectional area to which they apply must be specified. The capacity parameter is usually based on the total column cross section minus the area blocked for vapor flow by the downcomer(s). Eor the E-factor, typical operating ranges for sieve plate columns are... 

A tower diameter is selected based on Souders-Brown (20-50 percent conservative, usually) or Hunt s relation, Equation 8-250. 

Souders-Brown flooding constant defined by Equation 8-286... 

Trays are usually designed with F-factor from 0.25 to 2.0 for a turndown of 8 1. Pressure drop per theoretical stage falls between 3 and 8 mm Hg. Note that bubble cap trays are on the high side and sieve trays are on the lower end of the range. Varying tray spacing and system efficiency, the HETP for trays are usually between 24 in. and 48 in. [133]. The C-factor is the familiar Souders and Brown capacity equation. 

The principal factor that determines the column diameter is the vapour flow-rate. The vapour velocity must be below that which would cause excessive liquid entrainment or a high-pressure drop. The equation given below, which is based on the well-known Souders and Brown equation, Lowenstein (1961), can be used to estimate the maximum allowable superficial vapour velocity, and hence the column area and diameter,... 

This equation is conveniently represented, as suggested by Souders and Brown 57-1, by Figure 12.28, and it is easy to use such a diagram to determine the number of plates required. 

Algebraic Method for Dilute Gases By assuming that the operating and equilibrium curves are straight lines and that heat effects are negligible, Souders and Brown [Ind. Eng. Chem., 24, 519 (1932)] developed the following equation ... 

The Souders and Brown constant CSB is the C-factor [Eq. (14-77)] at the entrainment flood point. Most modern entrainment flooding correlations retain the Souders and Brown equation (14-80) as the basis, but depart from the notion that CSB is a constant. Instead, they express CSb as a weak function of several variables, which differ from one correlation to another. Depending on the correlation, CSB and us,flood are based on either the net area or on the bubbling area AB. 

Equations (3.89) and (3.90) equate the tray active area vapor loading VN to the maximum VM for determining the gas in liquid entrainment flooding of the tray. The early work of Souders and Brown [12], based on a force balance on an average suspended droplet of liquid, led to the definition of a capacity parameter VM- Both VN and Where refer to the active area of the tray. This active area is simply the net tower cross-section internal area less the downcomer areas. The downcomer areas include both the downcomer inlets and outlets. 

The jet flood equation is also based on the work of Souders and Brown [12]. This equation computes the ratio of the square power of the vapor load (noted in this chapter as Vload) to a constant, 8.75, to derive the tray flood. It has been used for over three decades by tray vendors (Koch and F.W. Glitsch [3]) to design and rate sieve-type trays. In many cases, especially for sieve-type tray design, jet flood governs tray flood and thus is the primary sieve tray design and rating equation. In contrast, Eqs. (3.88) through (3.90) are the principal equations for flood determination for both valve- and bubble cap-type trays. 

Smoker method. 123-126, 192 Snap-Grid , 466-467, 637, 650 Souders and Brown constant. 276 equation, 276, 480 Spiegel and Meier flood. MeUapak , 488, 490 mass transfer. 474, 532 ST-100 packing, 444 Standart efficiencies, 365 Stichlmair et al. packing maldistribution, 547 packing pressure drop model, 501 Strigle ... 

A tower must have sufficient cross-sectional area to handle the rising gases without excessive carry-over of liquid from one tray to another. By assuming that the frictional drag of the vapor on suspended liquid droplets should not exceed the average weight of a droplet, Souders and Brownf derived the following equation applicable for any specific location in the column ... 

Capps [188] examines sieve and valve tray capacity performance and Figure 8-151 [188] is offered for preliminary colunm sizing or for determining whether a debottlenecking study is justified. The correlation for flooding, tray rating, and design of a tray are all based on the capacity factor, Cx, equation (Souders and Brown [68] by Capps [188]). 

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