Engineering, 24.03.2021 17:10 cuddleslugsovifat

Cooling water for a chemical plant must be pumped from a river 2500 ft from the plant site. Preliminary design cans for a flow of 600 gal/min and 6-in. Steel pipe. Calculate the pressure drop and the annual pumping cost if power cost 3 cents per kilowatt-hour. Would the use of an 8-in. Pipe reduce the power cost enough to offset the increased pipe cost? Use $15/ft of length for the installed cost of 6-in. Pipe and $20/ft for 8-in. Pipe. Annual charges are 20 percent of the installed cost.

Answers: 2

Show answers

Answers

Answer from: kalbaugh

The power cost savings for the 8 inches pipe offsets the increased cost for the pipe therefore to save costs the 8-inch pipe should be used

Explanation:

The given parameters in the question are;

The distance of the river from the the site, d = 2,500 ft.

The planned flow rate = 600 gal/min

The diameter of the pipe, d = 6-in.

The pipe material = Steel

The cost of pumping = 3 cents per kilowatt-hour

The Bernoulli's equation is presented as follows;

$\dfrac{P_a}{\rho} + g\cdot Z_a + \dfrac{V^2_a}{2} + \eta\cdot W_p = \dfrac{P_b}{\rho} + g\cdot Z_b + \dfrac{V^2_b}{2} +h_f +W_m$

${P_a} = {P_b} = Atmospheric \ pressure$

Z_a = Z_b

Vₐ - 0 m/s (The river is taken as an infinite source)

W_m = 0

The head loss in 6 inches steel pipe of at flow rate of 600 gal/min = 1.19 psi/100 ft

Therefore; h_f = 1.19 × 2500/100 = 29.75 psi

$\eta\cdot W_p = \dfrac{V^2_b}{2} +h_f$

V_b = Q/ A_b = 600 gal/min/(π·(6 in.)²/4) = 6.80829479 ft./s

V_b ≈ 6.81 ft./s

The pressure of the pump = P = 62.4 lb/ft³× (6.81 ft./s)²/2 + 29.75 psi ≈ 30.06 psi

The power of the pump = Q·P ≈ 30.06 psi × 600 gal/min = 7,845.50835 W

The power consumed per hour = 7,845.50835 × 60 × 60 W

The cost = 28,243.8301 kW × 3 = $847.31 per hour

Annual cost = $847.31 × 8766 = $7,427,519.46

Pipe cost = $15/ft × 2,500 ft = $37,500

Annual charges = 20% × Installed cost = 0.2 × $37,500 = $7,500

Total cost = $37,500 + $7,500 + $7,427,519.46 = $7,475,519.46

For the 8-in pipe, we have;

V_b = Q/ A_b = 600 gal/min/(π·(8 in.)²/4) = 3.83 ft./s

h_f = 1.17 ft/100 feet

Total head loss = (2,500 ft/100 ft) × 1.17 ft. = 29.25 ft.

$h_p = \dfrac{V^2_b}{2 \cdot g} +h_f$

∴ h_p = (3.83 ft./s)²/(2 × 32.1740 ft/s²) + 29.25 ft. ≈ 29.5 ft.

The power of the pump = ρ·g·h × Q

Power of pump = 62.4 lb/ft³ × 32.1740 ft/s² × 29.5 ft.× 600 gal/min = 3,363.8047 W

The cost power consumed per annum = 3,363.8047 W × 60 × 60 × 3 × 8766 = $3,184,608.1

The Cost of the pipe = $20/ft × 2,500 ft. = $50,000

The total cost plus charges = $3,184,608.1 + $50,000 + $10,000 = $3,244,608.1

Therefore it is more affordable to use the 8-in pipe which provides substantial savings in power costs

Answer from: Quest

correct me if i’m wrong but i believe it’s false

Answer from: Quest

answer: jesus loves you

explanation:

Another question on Engineering

Engineering, 03.07.2019 14:10

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Answers: 3

Answer

Engineering, 04.07.2019 19:20

Consider airflow over a flat plate of length l = 1.5 m under conditions for which transition occurs at le = 0.9 m based on the critical reynolds number, re,e = 5 x 10. evaluating the thermophysical properties of air at 400 k, determine the air velocity. (hint: use the tables to find the properties of air)

Answers: 3

Answer

Engineering, 06.07.2019 03:10

List and describe the parts of boxford cnc milling machine with pictures?

Answers: 2

Answer

Engineering, 06.07.2019 03:20

Figure out the odd statement about ceramics in the following (a) good insulators of heat and electricity (b) usually less desire than metals (c) ductile in nature (d) contains both metallic and nonmetallic elements

Answers: 3

Answer

You know the right answer?

Cooling water for a chemical plant must be pumped from a river 2500 ft from the plant site. Prelimin...

Questions