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Towers, cost

Maintenance cost. Maintenance for air-cooled equipment as compared with sheU-and-tube coolers (complete with coohng-tower costs) indicates that air-cooling maintenance costs are approximately 0.3 to 0.5 those for water-cooled equipment. [Pg.1082]

FIG. 14-81 Fabricated costs and installation time of towers. Costs are for shell with two beads and sldrt, but without trays, packing, or connections. (Peters and Timmerhatis, Plant Design and Economics for Chemical Engineers, 4th ed., McGraw-Hill, New Yoik, 1991. )... [Pg.1406]

Although these units find initial application in areas of limited water, they have not been limited to this situation. In many instances they are more economical than cooling tower systems and have been successfully applied in combination with cooling towers (see Figure 10-184). Economic comparisons should include such items as tower costs, basin, make-up facilities, water treatment, pumps for circulation, power supply, blow down, piping, etc. For small installations of air-cooled units, they should be compared... [Pg.259]

For some years it was common practice to quote three different figures, based on the tower s performance as a percentage of the year. For example, in air conditioning it could be shown that the tower would achieve its design for 95 per cent of the year. Alternatively, a tower costing 15 per cent less could obtain its design parameter for 85-90 per cent of the year. Only the operator would know whether the 85-90 per cent or less was acceptable, while the economists would welcome the saving of financial capital. [Pg.527]

JUONG, J. F. Hydrocarbon Process., 48(7) (1969) 200. How to estimate cooling tower costs. [Pg.785]

Recirculation, Fogging These are major problems. Design accommodation, restrictions on tower dimensions, orientation with prevailing winds, and added capacity for recirculation can boost tower cost. Because of its elevated discharge, the natural-draft tower rarely has the trouble with recirculation and fogging. [Pg.78]

The size of a cooling tower is normally established by the amount of air that is needed for a specified cooling job. The tower fill, which minimizes air rate requirements generally minimizes overall tower costs as... [Pg.287]

The absorption column is sized according to two key parameters, these are to design for optimum mass transfer and optimum unit cost. A column internal diameter can be estimated according to the liquid and gas flowrates by utilizing graphs and nomographs such as those contained in Ref. A3. These recommendations have been refined using a computer-based mathematical model. The model predicts the required number of trays for a specified column internal diameter. These results enable a compromise to be achieved between tower cost and tower performance. [Pg.284]

In many cases, the vapor rate changes over the length of the tower, and the theoretical diameter based on the allowable vapor velocity varies. Occasionally, two different diameters are used for different sections of one tower. Cost considerations, however, usually make it impractical to vary the diameter, and the constant diameter should be based on the tower location where allowable velocity and throughput rates require the largest diameter. [Pg.659]

Fabricated costs and installation time of towers. Costs are for shell with two heads and skirt, but without trays, packing, or connections. [Pg.708]

With rising solvent concentration, the main tower cost declines, but the solvent-cooler cost and the utility cost increase. The net result is shown by the solid lines in Figure 5 where the costs are represented as fixed, operating, and total costs. A compromise must be made between the tower costs and the cooler and utility costs to determine the optimum solvent concentration. [Pg.35]

Finally, Table 3.2.1 contains two economic relations or rules-of-thumb. Equation 3.2.20 states that the approach temperature differences for the water, which is the difference between the exit water teir jerature and the wet-bulb temperature of the inlet air, is 5.0 "C (9 °F). The wet-bulb temperature of the surrounding air is the lowest water temperature achievable by evaporation. Usually, the approach temperature difference is between 4.0 and 8.0 C. The smaller the approach temperature difference, the larger the cooling tower, and hence the more it will cost. This increased tower cost must be balanced against the economic benefits of colder water. These are a reduction in the water flow rate for process cooling and in the size of heat exchangers for the plant because of an increase in the log-mean-temperature driving force. The other mle-of-thumb. Equation 3.2.21, states that the optimum mass ratio of the water-to-air flow rates is usually between 0.75 to 1.5 for mechanical-draft towers [14]. [Pg.116]

Wet-dry towers. Figure 9.17(g), employ heat transfer surface as well as direct contact between air and water. Air coolers are used widely for the removal of sensible heat from cooling water on a comparatively small scale when cooling tower capacity is limited. Since dry towers cost about twice as much as wet ones, combinations of wet and dry sometimes are applied, particularly when the water temperatures are high (near 160°F) so that the evaporation losses are prohibitive and the plumes are environmentally undesirable. The warm water flows first through tubes... [Pg.273]

Note This 40,000 has been determined by developing an accurate estimate of the abscrption-tower cost and can be taken as the actual net savings. [Pg.839]

Convex set in linear programming, 382 Conveyors, cost of 569-571 Coohng towers, cost of 810 COPE, 128... [Pg.899]

Thermal pollution, control of 89-90 Title page for reports, 455-457 Tolerance intervals, 759 Total capital investment, 157 Towers, cost of 707-713,810 TOXLINE, 48... [Pg.909]

Purchased tower cost = (1413X0.02831XZX0.785D )... [Pg.1214]


See other pages where Towers, cost is mentioned: [Pg.118]    [Pg.532]    [Pg.526]    [Pg.466]    [Pg.285]    [Pg.322]    [Pg.335]    [Pg.62]    [Pg.839]    [Pg.285]    [Pg.286]    [Pg.285]    [Pg.118]    [Pg.94]    [Pg.466]    [Pg.446]   
See also in sourсe #XX -- [ Pg.707 , Pg.708 , Pg.709 , Pg.710 , Pg.711 , Pg.712 , Pg.810 ]




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