Cooling towers sizing example

The paper presents an analysis of water cooling tower data. It describes a method to estimate cooling tower weight, volume, number of cells, motor size and price. Two examples are given illustrating the use of calculation techniques developed. 

Conveyors, mechanical, 76-88 Cooling towers, 280-285 approach to equilibrium, 234 bid data required, 284 kinds of fill, 282 performance curves, 284 sizing example, 281,282 sketches, 283... 

The problem of cooling tower selection is not merely to determine the required size and cost of a tower to meet a given set of conditions, but also to select the optimum des conditions on the basis of overall plant economy. The following examples show how the charts (Figures 3-2 through 3-5) are used and deal with the various problems involved in selecting the optimum tower. 

An increase in heat load does not require a proportional increase in size. Considering the results in Example 5, maximum benefits will be obtained if the minimum amount of water is cooled to the lowest desired temperature. Once the water is cooled, it is desirable to add as much heat as possible before the water is returned to the cooling tower. 

To select correct size tails tower and cooler absorber, to meet your specific requirements, follow the dotted line in the two charts. For example, using a 75% concentration of feed gas, 90 cooling water, and absorbing 2,000 Ibs./hr. HCI,- a 92 tube cooler absorber would be required in con unction with a 24" diameter tower. To produce acid over 20 Be to 22 Be, use 12-foot long tubes in ail instances where cooling water temperature falls to left of black dotted line in cooler absorber selection chart. Use 9-foot long tubes where temperature point is to the right of the dotted line. 

Another form of redundancy is the excess capacity often built into plants with more than one processing line. If two sets of drying towers are used, for example, the capacity of each may be more than 50% of the plant design capacity. The primary justification for multiple trains usually is to enhance turndown capability or to allow continued operation even when one train must be shut down. The same approach may be taken with the cooling section. Given the sizes of chlorine gas headers, valves would be expensive and probably ineffective as shutoff devices. Many plants therefore use U- or J-shaped traps in the piping. These can be filled with water or acid to stop the gas flow and to isolate equipment for maintenance. 

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