Water horsepower

We say that the useful work of the pump is called Water horsepower (WHp). It is demonstrated mathematically as ... 

Given Pressure or Fdead required = 100 feet at 200 gpm. What is the water horsepower required for this pump Assume a sp. gr. of 1.0... 

If the specific gravity at pumping temperature were not equal to 1.0, then the water horsepower would be adjusted by the spceifie gravity. 

Figures 3-36A, 3-36B, and 3-36C represent typical and actual performance curves showing discharge total head (head pressure at pump outlet connection for any fluid), required minimum water horsepow er (for pumping water), and capacity or pumping volume of the pump (for any fluid) for several impeller diameters that would fit the same case (housing). In addition the important NPSHr (net positive suction head required by the pump) charac-...

Energy recovery turbine systems are available for very high-pressure RO (seawater) plants, whereby brine reject water under high pressure can be used to spin an energy recovery turbine, reducing the feed-water horsepower requirements (and hence electricity costs) by 30 to 32%. 

Overall efficiei cy (in an electrically driven pump) Eo — water horsepower -j-electrical horsepower. It is the ratio of the actual power developed in the water end, i.e., pounds of water raised times equivalent head -4- 33,000, to the amount of ehictrical energy delivered to the motor as measured appropriately on the motor switchl>oard. 

The brake horsepower, in the case of a power pump, is the horsepower delivered to the pump, as measured by a dynamometer or suitable means. Figure 33 gives the water horsepower and the brake horsepower required at usual quantities and heads For other conditions multiply or divide the horsepower obtained from the diagran proportionately. EPh = included in F m). 

Exam ple,—The theoretical water horsepower required to pump 500 gal. per minut against 300 ft. head is, as calculated from the indicator diagram, 38.5 horsepower at 80 per cent efficiency the brake horsepower required will be 48 hp. 

Heat units consumed per water horsepower-hour.B.t.u. 

Beware These figures represent water horsepower only. No allowance has been made for any losses. These figures assume frictionless pipe, a 100 percent pump efficiency, and a perfect conversion of the energy (from whatever source) into the mechanical motion required by the pump mechanism. 

In most instances, we must multiply the calculated water horsepower by at least a factor of two or three to compensate for pump efficiency, gas engine inefficiency, and pipe losses. 

Motor-driven, multistage reciprocating compressors have reportedly been the most popular choice for aeroderivatives. Motor-driven, oil-fiooded screw compressors are also used in some cases. High horsepower, multistage centrifugal compressors, similar to those used at many pipeline compressor stations, may be required for the newer heavy-duty units if the distribution pipeline pressure is insufficient (see Pipelines). Gas turbines have more stringent fuel-gas specifications in terms of cleanliness than do gas-fired boilers. Thus oil- and water-knockout systems, coalescing filters, and fine-mesh filters are used. 

Horsepower (British) Pounds water evaporated per hour at 212 F 2.64... 

Pounds water evaporated from and at 212 F. Horsepower-hours 0..379... 

FIG. 15-21 Continuous extraction of n-hiitylamine from kerosine into water. T = 1.23 ft, Z = 1.56 ft, no air-liquid interface, impellers centered, Vr/Ve X 1-57, residence time X 1.08 min. To convert feet to meters, multiply hy 0.3048 to convert inches to centimeters, multiply hy 2.54 and to convert horsepower to kilowatts, multiply hy 0.746. [Overcashiet Kingsley, and Olney, Am. Inst. Chem. Eng. J., 2, 529 (1.956), with permission.]... 

Development The following discussion relates specifically to the use of what could be called radial-inflow, centrifugal-pump power-recovery turbines. It does not apply to the type of unit nurtured by the hydroelecti ic industry for the 1 ge-horsepower, large-flow, low- to medium-pressure differential area of hydraulic water turbines of the Felton or Francis runner type. There seems to have been little direct transfer of design concepts between these two fields the major manufacturers in the hydroelectric field have thus far made no effort to sell to the process industries, and the physical arrangement of their units, developed from the requirements of the hydroelectric field, is not suitable to most process-plant applications. 

Hot water re-eireulation pumps are small fractional horsepower models used to heat homes and buildings with circulated hot water through radiators. 

An inerease in ambient air temperature will deerease the available energy for the generator. This assumes that the fresh feed and eoke burn remains eonstant. The expander horsepower does not ehange, but the air blower horsepower inereases with inereased air temperature, eausing the exeess energy to deerease. Steam and water may need to be added to the flue gas flow at various points in the system to eontrol afterburning. In Figure 4-64, the solid eurves are for a normal flow of steam. The dotted eurves are for inereases in the steam rate by 3.05 times, 4.85 times, and 6.05 times the normal flowrate. 

Example 6. Use the Increase in Fan Horsepower to Raise Circulation Rather Than Lower Cold Water Temp. 

Example. A water-cooled unit with an evaporator temperature of-40°F will require 3 horsepower/ton of refrigeration. A ton of refrigeration is equal to 12,000 BTU/hr. Here are equations for these curves in the fonn ... 

The following information was used in olefin plant case studies to determine if the ethylene/propylene cascaded refrigeration systems had enough horsepower for various plant operations. The propylene was condensed against cooling water at 110°F and the ethylene was condensed against propylene at -20°F. For comparison, the horsepower requirements for each refrigerant alone are also shown. 

If the system differential pressure requirements are low, sometimes a fan can be used. A fan is limited to a maximum of about 65 inches of water (just over 2psi) in vacuum service or 77 inches of water in pressure service (just under 3psi). To estimate fan horsepower use the equations found in Chapter 6 in the section entitled Horsepower Calculation. In lieu of manufacturer s data use an adiabatic efficiency of 50% for initial work. 

We wish to separate titanium dioxide particles from a water suspension. The method chosen is centrifugation. The unit is a continuous solid-bowl type with a bowl diamter of 400 mm, a length to width ratio of 3.0, and the unit operates at 2,000 rpm. The feed contains 18 % (weight basis) solids and is fed to the unit at 2,500 Liters/hr at a temperature of 95° F. The average particle size is 65 /tm. (a) Determine the amount of solids recovered per hour (b) Determine the solids concentration in the centrate (c) Determine the horsepower requirments for the centrifuge (d) Size a graviy settler to remove an additional 15 % of the solids. 

Determine which 2-in. Schedule 40 mixer model is required to process water-like fluids at a flowrate of 10 gpm. What is the required theoretical horsepower (Data viscosity = 1 cP Density = 62.4 Ib /ft assume = 0.00015 ft)... 

Where hot ambient temperatures are expected, overall turbine efficiency and horsepower output can be increased by installing an evaporative cooler in the inlet. Inlet air flows through a spray of cold water. The temperature of the water and the cooling effect caused by the inlet air evaporating some of the water cools the inlet air. In desert areas where the inlet air is dry and thus able to evaporate more water before becoming saturated with water vapor, this process is particularly effective at increasing turbine efficiency. 

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