Traditional Design Method

Traditional Design Method The traditionally employed conventional procedure for designing packed-tower gas-absorption systems involving chemical reactions makes use of overall volumetric mass-transfer coefficients as defined by the equation... 

The traditional design method normally makes use of overall values even when resistance to transfer lies predominantly in the liquid phase. For example, the COg-NaOH system most commonly used for comparing the Kg< values of various tower packings is a liqiiid-phase-controlled system. When the liqiiid phase is controlling, extrapolation to different concentration ranges or operating conditions is not recommended since changes in the reaction mechanism can cause /cl to vary unexpectedly and the overall values do not explicitly show such effects. 

Determine whether commercial design overall KgO- values are available for use in conjunction with the traditional design method, being careful to note whether the conditions under which the KqU data were obtained are essentially the same as for the new design. Contact the various tower-packing vendors for information as to whether K a data are available for your system and conditions. 

While the traditional design method is reported here because it has been used extensively in the past, it should be used with extreme... 

FIGURE 9.1 The traditional design method is a lengthy and expensive process. 

Computational fluid dynamics methods, which typically calculate flow field variables at himdreds of thousands of points inside the reactor to come up with overall reaction rates, are far better suited for the analysis of such systems. Another difference between CFD and traditional design methods is the minimal reliance of CFD on experimental data and extrapolation of that data to different scales, a process known as scale-up. Computational fluid dynamics relies on solving the fundamental equations of motion and conservation. These equations are scale independent and can be solved directly for the full-scale equipment. 

These reliability calculations show that traditional design methods probably lead to structures in which the chances of the load effect overcoming the strength effect are very small. However, these probabilities are sensitive to the assumptions about load values and strength values. Although the variability associated with... 

Manufacturers need to continually update their traditional design methods in order to keep pace with rapidly evolving technologies and an increasingly demanding marketplace. Consumer demand products that are increasingly faster, easier to use, and lower in cost. 

Understanding the interactions between CP systems is becoming more complex particularly in the marine and offshore industry. The search for oil and gas in deeper waters and remote environments has resulted in engineering designs with many components on the seabed as well as at the sea surface. However, traditional design methods are inadequate in these situations due to the important interactions that may occur between CP systems [19]. 

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