This is problem 6-19 from El-Wakil’s Powerplant Technology book -- a 35,000 lbm/h double-effect evaporator receives...

This is problem 6-19 from El-Wakil’s Powerplant Technology book -- a 35,000 lb_m/h double-effect evaporator receives motive steam at 40 psia and 300°F. Pretreated raw water enters at 60°F. The pressure in the second effect is 5 psia. Calculate, for equal heat heads, (a) the amount of motive steam required, in pound mass per hour, and (b) the surface areas for each evaporator, in square feet.

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samet mamat answered 2 years ago

This is problem 6-6 from El-Wakil’s Powerplant Technology book -- consider a powerplant operating on an...

This is problem 6-6 from El-Wakil’s Powerplant Technology book -- consider a powerplant operating on an ideal Rankine cycle without feedwater heating. Steam enters the turbine saturated at 1000°F at the rate 5x106 lbm/h. The turbine exhausts to a surface condenser area of 402,467 ft2 and cooling water inlet temperature of 60°F. Calculate (a) the plant net power, in megawatts, (b) the plant efficiency, in percent, (c) the cooling water exit temperature, in degrees Fahrenheit, and (d) the water flow...

This is problem 7-6 from El-Wakil’s Powerplant Technology book -- a wet cooling tower receives 1.5x106...

This is problem 7-6 from El-Wakil’s Powerplant Technology book -- a wet cooling tower receives 1.5x106 lbm/min of condenser water at 96 degFahrenheit, and 1.25x106 lbm/min of air at 1 standard atmosphere, 62 degFahrenheit, and 50 percent relative humidity. The air leaves saturated at 82 degFahrenheit. Calculate (a) the exit water temperature, in degrees Fahrenheit, and (b) the percent condenser cooling water makeup due to evaporation.

This is problem 6-9 from El-Wakil’s Powerplant Technology book -- consider for simplicity an ideal Rankine...

This is problem 6-9 from El-Wakil’s Powerplant Technology book -- consider for simplicity an ideal Rankine cycle with turbine inlet and exit steam at 2500 psia and 1000°F, and 1 psia, respectively, and no feedwater heating. The steam mass flow rate is 2x106 lbm/h. The plant has two-pass surface condenser with 45-ft-long 7/8-in 18-BWG-type 304 stainless steel tubes. Cooling water enters the tubes at 70°F and 7 ft/s. With no flows into the condenser other than turbine steam, find (a)...

This is problem 7-12 from El-Wakil’s Powerplant Technology book -- it is desired to compare the...

This is problem 7-12 from El-Wakil’s Powerplant Technology book -- it is desired to compare the effect of two types of dry cooling tower systems on powerplant performance. The towers are of the indirect cooling type. One operates with a surface condenser with an 8 degrees Fahrenheit terminal temperature difference, and the other with a direct-contact condenser with 0 degrees Fahrenheit terminal temperature difference. Consider for simplicity a simple ideal Rankine cycle with inlet saturated steam at 1000 psia. Further...

This is problem 6-12 from El-Wakil’s Powerplant Technology book -- a condensing only feedwater heater uses...

This is problem 6-12 from El-Wakil’s Powerplant Technology book -- a condensing only feedwater heater uses 7/8-in-OD 90-10 copper-nickel tubes. It receives 84,000 lbm/h of 95 percent quality bled steam at 20 psia, and 160,000 lbm/h of drain from the next higher pressure heater at 240°F. 3.9x106 lbm/h of feedwater goes through the heater at 7 ft/s, 2000 psia, and 195°F. The terminal temperature difference is 5°F. Determine the size, length, and number of tubes based on a U-tube design....

This is problem 7-15 from El-Wakil’s Powerplant Technology book -- a spray pond is used to...

This is problem 7-15 from El-Wakil’s Powerplant Technology book -- a spray pond is used to cool a 200-MW powerplant that has a 39 percent efficiency. The condenser cooling water outlet temperature is 90 degF. The atmosphere is at 70 degF and 60 percent relative humidity. The spray nozzles have ntu = 0.15, r = 0.015 and f = 0.25. Determine (a) the number of spray modules required, (b) the flow per module, in gallons per minute, and (c) the...

This is problem 5-13 from El-Wakil’s Powerplant Technology book -- a 50 percent reaction stage in...

This is problem 5-13 from El-Wakil’s Powerplant Technology book -- a 50 percent reaction stage in a steam turbine undergoes a total of 20 Btu/lbm enthalpy drop. The nozzle efficiency and angle are 88 percent and 25°, respectively. The blades move at 420 ft/s and have Vr1 = 332 ft/s, Vs2 = 386 ft/s, and ? = 22°. The steam flow is 1.08x106 lbm/h. Find (a) the work done by the stage in horsepower and megawatts, (b) the blade efficiency,...

This is problem 5-17 from El-Wakil’s Powerplant Technology book -- consider a simple combination turbine with...

This is problem 5-17 from El-Wakil’s Powerplant Technology book -- consider a simple combination turbine with one Delaval impulse stage and one 60 percent reaction stage. The nozzle of impulse stage receives steam at 900 psia and 900°F and leaves it at 300 psia. The nozzle efficiency is 97 percent and its angle is 20°. The blade speed is optimum and its velocity coefficient is 0.95. The impulse stage is followed on the same shaft by the reaction stage which...

This is problem 5-5 from El-Wakil’s Powerplant Technology book -- steam expands ideally in a turbine...

This is problem 5-5 from El-Wakil’s Powerplant Technology book -- steam expands ideally in a turbine from 2500 psia and 1000 degFahrenheit to 1 psia. Compare the maximum steam velocities and the number of stages required by (a) a velocity-compounded impulse turbine, (b) a pressure-compounded impulse turbine, and (c) a 50 percent reaction turbine if the optimum blade velocity may not exceed 885 ft/s in any of them. Take all nozzle angles to be 25°.

This is problem 7-3 from El-Wakil’s Powerplant Technology book -- a natural-draft cooling tower is 450...

This is problem 7-3 from El-Wakil’s Powerplant Technology book -- a natural-draft cooling tower is 450 ft high. Air enters the tower at 14.696 psia, 50°F, and 50 percent relative humidity and leaves in a saturated condition. The pressure drop in the tower is 0.015 psi. Calculate (a) the air exit temperature, in degrees Fahrenheit, and (b) the makeup due to evaporation, in pound mass per pound mass of dry air.

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