Chemical Engineering Answers

Velocity profile of a liquid is shown below:

If the shear stress per unit surface area on the rigid plate over which the liquid flows is measured to be 0.083 N/m².

1.    Calculate the viscosity of the liquid .

2.    What is the maximum velocity at the free surface if the plate is tilted by an angle of 60^o to the horizontal plane and the liquid is allowed to down freely keeping the same film thickness? There is no pressure gradient in the direction of flow. Density of the liquid is 887 kg/m³.

Heat is flowing through an annular wall of inside radius ‘R_i’ and outside radius ‘R_o’. The thermal conductivity varies linearly with the temperature from k_i at T_i and k_o at T_o. Find the temperature profile and develop an expression for the heat flow through the wall at r = R_o . 

benzothiophene could be converted to ethylbenzene by a hydrodesulfurization reaction. Before you commit the time and money to design a reactor for this reaction, you may want to attempt to verify that the production of ethylbenzene is economically feasible. In other words, are the products worth more than the reactants and energy required to make them? If you discover the answer is no, you may have saved thousands of dollars in design fees.

(a) Reactor (Plug Flow, Mixed Flow, Packed Bed, Fluidized Bed, etc.) (b) Adiabatic vs. Isothermal reactor operation 

(c) Reactor temperatures and pressures

(d) Feed ratio of hydrogen to benzothiophene 

(e) Effluent conditions and compositions 

(f) Weight of catalyst required 

(g) Material of construction for the reactor (Hint: Is the material susceptible to accelerated corrosion due to the presence of sulfur or hydrogen?) 

(h) Reactor shape and dimensions 

(i) Reactor wall thickness  

b) Nitrous oxide decomposes according to the second order rate equation 2N₂0→2N₂ +0₂ The rate constant is 977 cm³/ (mol. s) at 895°C. Calculate the fraction decomposed at 1s, 10s, and at 10 min in a constant volume batch reactor. The initial pressure (all N₂O) is 1 atm.

Explain problem step by step.

A mixture containing 10% ethanol (E) and 90% H₂O (W) by weight is fed into a distillation column at the rate of 107.51 kg/h. The distillate (top product) contains 90.63 % ethanol and the distillate is produced at a rate of one tenth of that of the feed. 

_{Draw and label a flow chart of the process before solving the problem. Perform material (total) and ethanol balances to calculate the mass fraction of ethanol in the bottom product to at least four decimal places.}

10. In a curved prestressed bridge, how should the guided bearings in piers of the curved region be oriented with respect to the fixed bearing in abutment?

3) A solution of washed raw cane sugar is coloured by the presence of impurities. It is to be decolourised by the treatment with an adsorptive carbon in a contact filtration plant. The data for an equilibrium isotherm is given below. The original solution has a colour concentration of 9.6 measured on an arbitrary scale and it is desired to reduce colour to 10% of its original value

Kg carbon/kg solution:

0

0.001

0.004

0.008

0.02

0.04

Colour units /kg solution

9.6

8.6

6.3

4.3

1.7

0.7

Convert the data to a suitable form for plotting the equilibrium isotherm and determine the quantity of fresh carbon required per 1000 kg of solution for a two stage counter-current operation?

Explain briefly with step by step process?

12)Use Cauchy integral formula for derivatives evaluate ∮c z²-2z/(z+1)^2 (z²+4)dz, where C is |z + 2) <2.

11)Evaluate∫C Im(Z)dz, where C is z = {(t-2i, 1≤t≤2. ; 2-i(4-t), 2<t≤3'