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The Figure below shows a cross section through an insulated heating pipe which is made from steel (k = 45 W / m K) with an inner radius of 150 mm and an outer radius of 155 mm. The pipe is coated with 100 mm thickness of insulation having a thermal conductivity of k = 0.06 W / m K. Air at Ti = 60°C flows through the pipe and the convective heat transfer coefficient from the air to the inside of the pipe has a value of hi = 35 W / m2 K. The outside surface of the pipe is surrounded by air which is at 15°C and the convective heat transfer coefficient on this surface has a value of ho = 10 W / m2 K. Calculate the heat loss through 50 m of this pipe. 


A fuel is analyzed and found to contain; 75.0 wt% methane, 10.0% ethane, 5.0% ethylene and the balance water. The flowrate of the fuel is 102.7 kg/h. Calculate the molar composition of this gas on both a wet and a dry basis and the ratio(mol H2O/ mol dry gas). If tgis fuel is to be burned with 28% excess air, what is the required air feed rate (kmol/h)? How would the answer change if the combustion were only 40% complete?

1 kg of ait at 1 bar 15 degree centridage is compressed reversibly and adiabtically in a pressure of 4 bar.Calculate the final temperature and the work input.

An absorption operation is required to remove CO2 from a 250 kmol/hr flue gas stream using an aquaeous 20 mole% MEA solution supplied at a flow rate of 1.5 times the minimum. The gas feed contains 13 mole% CO2 in air, and the exhaust gas stream should contain no more than 0.7 mole% CO2. The supplied MEA solution contains 1.1 mole% CO2. This absorption operation column has internal height and diameter of 10 and 1 m, respectively. The column should be designed for a pressure drop of 0.5 inches H2O per foot of packing.

a) Determine the mole% CO2 in the liquid stream leaving the column and determine the number of transfer units.

Equilibrium data:

x:0.010 0.0125 0.015 0.0175 0.020 0.0225 0.025 0.0275 0.030 0.035 0.040 0.045 
y:0.002 0.005 0.009 0.015 0.021 0.028 0.037 0.047 0.059 0.090 0.135 0.19 

Other data:

𝑀̅𝑠𝑜𝑙𝑣𝑒𝑛𝑡 = 26.6, 𝑀̅CO2 = 44 g.mol-1 , kOG = 0.85 mol.m-2 .s-1 , ρg,ave. = 1.28 kg.m-3 , ρl,ave. = 1000 kg.m-3 , ηave. = 1.0 cSt

condition of water-

U=2500KJ/KG, T=70C

Determine state of water.

Dilute sulphuric acid is to be pumped between tow storage tanks using 800m long pipe with 5cm inner diameter at a rate of 100m/hr. the overall difference between the liquid levels in the two tanks is 5cm . the tanks are open to atmospheric through vents . the specific gravity of the acid is 1.3 and the viscous is 0.001Ns/msquare . in the pipe work, there is a globe valve(fully open equivalent to 100pipe diameters ) and four 90 degree standard radius bends (30 pipe diameters each ) the relative roughness of the pipe is 0.002. Any other losses can be considered negligible. what is the power requirement of the centrifugal pump used if the efficiency of the pump is 64% ? take the friction factor of the pipe as 0.031 

For a multi component system (1,2,3,...,n), two-phase system (a and b), show that the condition for chemical equilibrium is μia= μib for i=1,2,3,...,n.

Determine minimum fluidization velocity of sand particle using water at 20 oC. The sand particles are mono-sized with surface volume spherical equivalent diameter dsv= 162 micron, a sphericity of 0.9

and density 2600 kg/m3

A 10.00-cm shaft rides in a 10.03-cm sleeve 12 cm long, the clearance space being filled with lubricating oil at 40oC (μ=0.11 Pa-s). Calculate the energy, in W, generated when the shaft turns at 100 rpm

2. An organic liquid leaves a reactor at 70ºC and it is necessary to reduce its temperature to 45ºC before the next unit operation. A shell-and-tube heat exchanger is to be used, and the organic liquid will flow on the shell side. The exchanger has 110 tubes, and the coolant in the tubes will be water entering at 15ºC. The tubes have a single pass – i.e. the water is divided across all tubes equally and flows just once through the exchanger. The total flow rate of water is of 75,000 kg h−1 , and the water exits the exchanger at 28 ºC. Using the Information Sheet where appropriate, determine:

a) the flow rate of the process liquid (in kg s−1 ), [5 marks]

b) the log mean temperature difference if the streams are in countercurrent flow, [5 marks]

c) the tube-side film heat transfer coefficient if the tubes have an inside diameter of 14.8 mm, [10 marks]

d) the heat transfer area if the overall heat transfer coefficient is 1100 W m−2K−1 . [5 marks]


Specific heat capacity of process liquid 2200 J kg-1K-1

Specific heat capacity of water 4190 J kg−1K-1

Viscosity of water 0.758 × 10−3 N s m−2

Thermal conductivity of water 0.617 W m−1K−1

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