Cooling towers interference

The use of cooling tower basins and process water pumps as fire water supply is not recommended. This water is usually treated with chemicals or may be contaminated with hydrocarbons that interfere with the use of foam extinguishing agents. At best, this supply could serve as a secondary system, should the primary supply be interrupted, using emergency connections. 

Interference is defined as an adulteration of the atmosphere entering the tower by a portion of the atmosphere leaving another nearby cooling tower. Recirculation is an adulteration of the atmosphere entering the tower by a portion of the atmosphere leaving the tower. Both are illustrated in Figure 6.8. 

These problems are typical in mechanical-draft cooling towers and virtually nonexistent in hyperbolic towers because of the height of vapor discharge. The magnitudes of interference and recirculation depend primarily on wind... 

The entering of a tower by hot, humid air discharged from another tower is tower interference. No thermal test code makes provision for tower interference it is necessary to determine what the wet bulb will be at that particular location in the plant. Many times the tower can be made smaller by moving it a few feet or by angling it to escape the down-wind vapor from an operating cooling tower. 

Problems associated with biofilms. Once bacteria begin to colonize surfaces and produce biofilms, numerous problems begin to arise, including reduction of heat-transfer efficiency, fouling, corrosion, and scale. When biofilms develop in low-flow areas, such as cooling-tower film fill, they may initially go unnoticed, since they will not interfere with flow or evaporative efficiency. Over time, the biofilm becomes more complex, often with filamentous development. The matrix provided will accumulate debris that may impede or completely block flow. 

Interference from industrial installations or multiple tower arrangements can result from poor planning of plant additions. Careful planning will provide the most effective cooling results. In general, interference can be... 

In June 1980, the venturi scrubber was removed from Train 100, allowing operation with the spray tower only. Prior to the removal of the venturi scrubber, operation with a true spray tower-only configuration was not possible without some interference from the venturi, even with its adjustable plug wide open and minimum slurry flow for flue gas cooling. 

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