Pressure drop irrigated random packings

Table 4-la. List of graphical methods for determining the pressure drop of irrigated random packings... 

Other methods, found in literature, for predicting the pressure drop in irrigated random packings are based on the model which is applicable to tube flow, Eq. (3-2), [52-54, 56, 64]. They belong to the third group of models, which is discussed in the following. 

A number of different models have been published, describing the pressure drop in irrigated random packings for counter-current flow of the phases. Most of these models only cover the complex flow behaviour in the operating range below the loading hne, see Table 4-1. 

Hence, Eq. (4-45) for calculating the dimensionless pressure drop of irrigated random packings now leads to Eq. (4-47) ... 

The applicabiKty of Eq. (4-50) for determining the pressure drop of irrigated random packings at laminar liquid flow for Reynolds numbers in the range 0.1 < ReL < 2, was verified based on experimental pressure drop data for 25 mm metal Pall rings, taken by... 

Deriving the Equation for the Calculation of the Pressure Drop of Irrigated Random Packings... 

Hiuta et al. [305] proposed a theordical model based on the model of i un for predicting the pressure drop of dry and irrigated random packings, the wetted area, and also the liquid holdup. The model u two experimental constants different fixr different packing types and dimensions. The piediction accuracy of tiie pressure drop is 30%, but many of the data show up to 3 times greater error. The pre( ction accuracy of the liquid holdup mid of the wetted area is about 20%. 

This chapter takes a closer look at the calculation of the pressure drop of the irrigated packed bed Ap/H for randomly filled and stacked packing elements as well as structured... 

Model for Determining the Pressured Drop of Irrigated Random and Structured Packings 207... 

Model for Determining the Pressured Drop of Irrigated Random and Structured Packings, Based on the Known Resistance Coefficient t r for Single-Phase Flow and the Dimensionless Pressure Drop Ap/Apo... 

The correlations for determining the pressure drop Ap/H of irrigated random and structured packings, presented in Sect. 4.3, lead to the following conclusions ... 

As described above, it is possible to determine the pressure drop Ap/H of irrigated random and structured packings relatively accurately for practical applications for the entire parameter range of the varied systems, packing elements and constructive variables ds and H, see Eq. (4-63). The mean errors 5 (Ap/H) relating to the individual packing systems can be found in Tables 4-4a-e. 

We must determine the pressure drop of the irrigated, random 25 mm Biaiecki packing at the flooding point, if the specihc liquid load is up = 0.0111 ms. The physical properties are applicable to the air/water system at 1 bar and 293 K. The gas velocity uvyi at the flooding point is given as uv,pi = 1.776 ms, acc. to numerical Example 2.2. 

Table 5-la. Determination of pressure drop in irrigated packed column in counter-current flow acc. to Eq. (5-9) or (5-10) ( x-model) throughout the entire operating range up to flooding point. List of test points and relative mean errors 5 (Ap/H) for tested random packing, valid for system air/water, 1 bar, 273 K... 

A generally valid Eq. (3-8) was derived to calculate the pressure drop of dry, non-irrigated, random and structured packings. 

The advantage of determining the pressure drop of irrigated random and structured packings acc. to Eq. (4-48) lies in the fact that this method is applicable to a wide range of... 

The experimental vaUdation of the correlations developed to calculate the flooding point uv,Fi and the pressure drop of dry Apo/H and irrigated packings Ap/H was achieved by means of a systematic analysis of the random and structured packings, shown in Figs. 1-la and 1-lb. 

By using the equations derived for the calculation of each parameter, it was possible to condense the extensive research material, which is discussed in the summary of the results of this work in Chap. 6. The end of each chapter contains example calculations to illustrate the individual correlations for determining the vapour load factor at the flooding point of the liquid hold-up as weU as the pressure drop of irrigated and dry random packing elements. The numerical examples are practice-oriented and explain the correlations mentioned before, based on the examples of different packings. 

In 1990, a database was created for the purpose of evaluating aU experimental data, including literature data. It currently holds more than 1,200 experimental flooding point data, in excess of 1,100 Kquid hold-up data and more than 10,000 pressure drop data for irrigated random and structured packings. The number of test mixtures is 32. The result is a comprehensive data pool, which is constantly being updated with the addition of new experimental data. 

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