Cooling towers range

Water Treatment Industrial CleaningPipplications. Boiler and cooling tower waters are treated with lignosulfonates to prevent scale deposition (78). In such systems, lignosulfonates sequester hard water salts and thus prevent their deposition on metal surfaces. They can also prevent the precipitation of certain iasoluble heat-coagulable particles (79). Typical use levels for such appHcatioas range from 1—1000 ppm. 

Other Uses. As a biocide, chlorine dioxide is more effective than chlorine over a wider pH range. Chlorine dioxide is also less corrosive and more compatible with some materials of constmction. Chlorine dioxide has a wide variety of small appHcations in drinking water, food processing (qv), cooling towers, and oil recovery. In these areas, chlorite is the preferred source of chlorine dioxide. 

Water Systems These systems usually form the third highest cost item in chemical-plant anxiharies, with cooling towers representing the largest part of the investment. Although the installed cost increases with the terminal temperature range, an approximate cost correlation is given by... 

Mechanics-draft cooling towers normally are designed for L/Q ratios ranging from 0.75 to 1.50 accordingly, the vSues of KaV/L vaiy from 0.50 to 2.50. With these ranges in mind, an example of the use of the nomograph will readily explain the effecd of changing variables. 

Cycles of concentration involved with cooling-tower operation normally range from three to five cycles. Below three cycles of concentration, excessive blowdown quantities are required and the addition of acid to limit scale formation should be considered. 

This equation is good if the air temperature is 50°F or above, the cooling tower s approach to the wet bulb temperature is 5°F or above, and Hog is within a range of about 0.1 to 8. 

The Spray tree is used to distribute water over the wet deck in counterflow cooling towers. It can consist of a single header fitted with spray nozzles or, it can utilize spray branches with nozzles for wider coverage. Spray nozzle designers seek minimal pressure requirements and uniform coverage over wide flow ranges. 

Heat Load Amount of heat (in Btu) dissipated in a cooling tower. It is equal to the weight of water circulated per unit of time multiplied by the cooling range. 

The effects of wet bulb, approach and range on mecbanical draft cooling tower size is indicated in Figure 9-118. 

Assume that a given cooling tower is designed to reduce the incoming temperature of 10,000 gpm by 25°F (range). Then, assume that the level of chlorides in the make-up water is 250 ppm, and we do not want that level to go beyond 750 ppm in the circulating water. Allowable concentration ratio is 750/250 = 3. The approximate... 

Figure 9-126A. eS F wet bulb 30°F range, counterflow cooling tower performance curves. Used by permission of Counterflow Cooling Tower Performance, The Pritchard Corp. (now, Black and Veatch Pritchard Corp.) (1957). 

Cooling range (cooling tower), °F Concentration of solution, lb solute/ft solution... 

The range of total pressure indicated in the graph corresponds to the lowest value at which the condensation of H20/dioxane vapors is feasible by using cooling water at a maximum temperature of 35°C (as in when using water from the cooling tower), namely, without the extra cost of energy for the eventual production of chilled water. 

Electrolytic zinc smelters contain up to several hundred cells. A portion of the electrical energy is converted into heat, which increases the temperature of the electrolyte. Electrolytic cells operate at temperature ranges from 30 to 35°C (86 to 95°F) at atmospheric pressure. During electrowinning a portion of the electrolyte passes through cooling towers to decrease its temperature and to evaporate the water it collects during the process. 

In the phosphoric acid plant, the contributing sources of effluent are the cooling tower bleedoff and the scrubber liquor solution that contains concentrations ranging for phosphate from 160 to 200 mg/L and for fluoride from 225 to 7000 mg/L. 

The cooling tower blowdown flow rate range of 82 steam electric power generation plants using coal is 0-152,000 m /plant (mean 8440 m /plant), which is equal to 0-239 mVMW (mean 11.2 mVMW). 

---