Spray pond

Sufficient distance should be provided from the outer nozzles to keep spray from being carried over the sides of the basin. If it is not possible to provide 7.6 to 10.7 m (25 to 35 ft) of space, the pond should be enclosed with a louver fence, equal in hei t to the maximum height of the spray, to minimize drift loss. Also, during cold-weather periods, fogging can occur from the spray pond, so that consideration should be given to possible hazards to roadways or buildings in the immediate vicinity. 

Example 15 Cooling Capacity of a Spray Pond Determine the cooling capacity of a spray pond operating at the following conditions ... 

TABLE 12-3 Spray-Pond Engineering Data and Design ... 

From Spray Pond Bull. SP-51, Marley Co., Mission Woods, Kan., p.. 3. 

FIG. 12-24 Spray ponds cooling curves for steam-condensing service. 

TABLE 12-4 Degree Adjustment to Be Applied to Leaving-Air Wet-Bulb Temperature to Find Cooled-Water Temperatures of Spray Ponds ... 

Cooling tower and artificial spray pond Treated makeup 0.001 0.001 0.002 0.002... 

Aerators are often used for iron and manganese removal from deep well waters. Dissolved sulfur gases and some carbon dioxide are also removed, resulting in a slight elevation in pH levels. There are various designs but pressure aerators, aeration towers, and spray ponds, are common. 

In practice, aeration towers using coke or volcanic lava tend not to be as efficient as spray ponds in facilitating the precipitation of ferrous hydroxide consequently, there is usually a requirement for a cationic flocculant to aid the precipitation of the insoluble materials into a larger floe or denser sludge that can be removed by clarification or sand filtration. 

Cooling of water can be carried out on a small scale either by allowing it to stand in an open pond or by the spray pond technique in which it is dispersed in spray form and then collected in a large, open pond. Cooling takes place both by the transference of sensible heat and by evaporative cooling as a result of which sensible heat in the water provides the latent heal of vaporisation. 

A large land area is necessary for the spray pond. 

Natural-draft cooling towers evolved from spray ponds. The simplest and earliest design consisted of a small water spray pond surrounded with walls having inwardly sloping louvers. Figure 4.9 shows a cross section of a simple cooling tower formed by enclosing a spray pond with louvered walls. 

Figure 4.9 Cross section of a simple cooling tower formed by enclosing a spray pond with louvered walls.

When land costs are too high, spray ponds often provide a viable alternative to cooling ponds. It is estimated that a spray pond requires only about 5 to 10 percent of the area of a cooling pond due to the more intimate air-water contact. In addition, drift losses and corrosion problems are less severe than in cooling towers. 

Make appropriate assumptions about windage and evaporation losses and set out and solve an equation for blowdown. Windage losses will be about 1.0 to 5.0 percent for spray ponds, 0.3 to 1.0 percent for atmospheric cooling towers, and 0.1 to 0.3 percent for forced-draft cooling towers for the forced-draft towers in this example, 0.1 percent can be assumed. As for evaporation losses, they are 0.85 to 1.25 percent of the circulation for each 10-degree drop in Fahrenheit temperature across the tower it is usually safe to assume 1.0 percent, so E = AT/10, where AT is the temperature drop across the tower. Therefore, in the present case,... 

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