Chemical Engineering Answers

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 μ_i^a= μ_i^b 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]

INFORMATION

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

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]

INFORMATION

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

It is required to absorb 95 % of the acetone from a mixture with nitrogen containing 1.5% mol% of the compound in a counter current tray tower. The total gas input is 30 kmol/h and water enter the tower at a rate of 90 kmol/h. The tower operates at 300K and 1 atm. The equilibrium relation is y =2.53x. Determine the number of ideal trays necessary for this separation. Use the graphical method as well as the Kremser analytical method.

diffusivity of gas pair oxygen carbon tetrachloride is determined by observing steady state evaporation of carbon tetrachloride.The distance between carbon tetrachloride liquid level and the top of the tube is 17.1cm.the total pressure of the system 755mmHg.The vapour pressure of carbon tetrachloride at this temperature is 33mmHg.The cross sectional area of the two is 0.82cm^2.If it is found that 0.0208cm^3 of CCL4 evaporate in 10hours period.What is the diffusivity of gas pair carbon tetrachloride

diffusivity of gas pair oxygen carbon tetrachloride is determined by observing steady state evaporation of carbon tetrachloride.The distance between carbon tetrachloride liquid level and the top of the tube is 17.1cm.the total pressure of the system 755mmHg.The vapour pressure of carbon tetrachloride at this temperature is 33mmHg.The cross sectional area of the two is 0.82cm^2.If it is found that 0.0208cm^3 of CCL4 evaporate in 10hours period.What is the diffusivity of gas pass carbon tetrachloride

Two of the most common rocks at the surface of the earth are basalt and granite. As a budding engineering student, you would like to find the ratio of basalt to granite in a rock sample which has an average density of 2.96 g/cm3. The granite in the sample has a volume of 1.00 ft3 and weighs 171 lbs. The piece of basalt has a volume of 64 in3 and weighs 116 ounces. Find the percentage of basalt and granite which give the sample a density of 2.96 g/cm3