Calculate the recoverable waste heat (Q, in kCal/hour) from flue gases using the followingparameters: V (flow rate of the substance) 2000 m3/hr r (density of the flue gas): 0.9 kg/m3 Cp (specific heat of the substance): 0.20 kCal/kg oC DT (temperature difference): 120 oC h (recovery factor): 50% a. 21600 b. 43200 c. 25600 d. 34000

Calculate the recoverable waste heat (Q, in kCal/hour) from flue gases using the followingparameters: V (flow
rate of the substance) 2000 m3/hr r (density of the flue gas): 0.9 kg/m3 Cp (specific heat of the substance): 0.20
kCal/kg oC DT (temperature difference): 120 oC h (recovery factor): 50% a. 21600
b. 43200
c. 25600
d. 34000
by

1 Answer

Answer :

21600
by

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Last Answer : (A) A section of the exchanger in which change in temperature of one stream equals the average driving force in the section

In a boiler enthalpy of water supplied was 2000 kJ/kg. Enthalpy being added by fuel combustion is 3200 kJ/kg. Using first law of thermodynamics, find amount of heat supplied if steam generation rate is 10 tons per hour.

Description : In a boiler enthalpy of water supplied was 2000 kJ/kg. Enthalpy being added by fuel combustion is 3200 kJ/kg. Using first law of thermodynamics, find amount of heat supplied if steam generation rate is 10 tons per hour.

Last Answer : Heat supplied Q = m (h2-h1) …….(Steady flow energy equation for boiler) ; h2=3200 KJ/kg h1=2000 KJ/kg m = 10 Tons /hour = (10 x 1000)/3600 kg/sec = 2.77 Kg/sec Q = 2.77(3200-2000) = 3324 KJ/sec heat supplied for 10 Tons/hr steam generation

Waste heat from the outgoing flue gases in a thermal power plant is recovered by a/an (A) Economiser (B) Steam superheater (C) Air preheater (D) All (A), (B) and (C)

Description : Waste heat from the outgoing flue gases in a thermal power plant is recovered by a/an (A) Economiser (B) Steam superheater (C) Air preheater (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

If air is at pressure, p, of 3200 lbf/ft2 , and at a temperature, T, of 800 ˚R, what is the specific volume, v? (R=5303 ft-lbf/lbm-˚R, and air can be modeled as an ideal gas.)  A.9.8 ft^3/lbm  B.11.2 ft^3/lbm  C.13.33 ft^3/lbm  D.14.2 ft^3/lbm Formula: pv = RT v = RT / p

Description : If air is at pressure, p, of 3200 lbf/ft2 , and at a temperature, T, of 800 ˚R, what is the specific volume, v? (R=5303 ft-lbf/lbm-˚R, and air can be modeled as an ideal gas.)  A.9.8 ft^3/lbm  B.11.2 ft^3/lbm  C.13.33 ft^3/lbm  D.14.2 ft^3/lbm Formula: pv = RT v = RT / p

Last Answer : 13.33 ft^3/lbm

Calculate: a. Mass flow rate in lb/hr. b. The velocity at section 2 in fps  a. 800,000lb/hr;625ft/s  b. 900,000lb/hr;625 ft/s  c. 888,000lb/hr;269 ft/s  d. 700,000lb/hr;269 ft/s m = A1V!/V1

Description : Calculate: a. Mass flow rate in lb/hr. b. The velocity at section 2 in fps  a. 800,000lb/hr;625ft/s  b. 900,000lb/hr;625 ft/s  c. 888,000lb/hr;269 ft/s  d. 700,000lb/hr;269 ft/s m = A1V!/V1

Last Answer : 900,000 lb/hr;625 ft/s