Consider steady heat transfer between two large parallel plates at
constant temperatures of T1 582 K and T2 196 K that are 6.8 cm apart.
Assuming the surfaces to have emissivity 0.9 , determine the rate of heat
transfer between the plates per unit surface area assuming the gap
between the plates is

(a) filled with atmospheric air

(b) evacuated

(c) filled with fiberglass insulation, and

(d) filled with super insulation having an apparent
thermal conductivity of 0.00045 W/m · °C.

Data given:

Plastic 0.4 W/mK
brick 0.72W/m°C
plaster 0.36 W/m°C
cement 1.4 W/m°C
Polyurethane foam 0.025W/m °C
Glass fiber/fiber glass 0.036 W/m °C
Air 0.0198 W/m °C
Copper 380W/m °C

# just take the required data

An electric wire having a diameter of 2.3 mm and covered with a plastic
insulation of thickness 0.63 mm is exposed to air at 336 K and h= 32W/m2 K. It
is assumed that the wire surface temperature is constant at 415 K and is not
affected by the covering. Calculate the value of the critical radius. Calculate the
heat loss per m of wire length with no insulation and heat loss with insulation
being present.

Data given:

Plastic 0.4 W/mK
brick 0.72W/m°C
plaster 0.36 W/m°C
cement 1.4 W/m°C
Polyurethane foam 0.025W/m °C
Glass fiber/fiber glass 0.036 W/m °C
Air 0.0198 W/m °C
Copper 380W/m °C

# take from the data given just the required

A distillation column is required to purchase for a petrochemical industry. The chief engineer of the industry wants to evaluate the cost of the distillation column to make his purchase worthy. The data is not available with the vendor. So chief engineer of the company predicts that the estimation by using cost index data is most suitable to determine the cost. But the cost index table is available from the year 1980 to 1990. As a chief engineer describe a procedure to calculate cost of the equipment in current year 2020.

1. A slurry of particles with density 2000 kg/m3 is to be loaded into a thickener where the resulting voidage fraction is 0.89 and the superficial particle velocity is 2.8 mm/s. Calculate the particle system velocity.
2. Consider batch sedimentation system performed within a measuring cylinder where solids are settled according to Type 1 settling. The voidage fraction after the settling is 0.35 and the particle density is 2500 kg/m3 while the particle velocity is 0.0015 m/s.
2.1. What is the net flow of the solids?
2.2. Calculate the free falling velocity or terminal velocity if the correlation for the exponent n = 0.4.

An ideal benzene toluene mixture contains 6 moles of benzene and 4 moles of toluene at 25 ° C. The saturation steam pressure of pure benzene at 25 ° C is 96 Torr, the saturation steam pressure of pure toluene is 29 Torr. Initially, the mixture at 760 Torr pressure is only liquid. The total pressure is then slowly reduced to a pressure of 60 Torr. Calculate the composition of liquid phase and vapor phase, and liquid and vapor mole fractions. (please show all the steps)

Discuss the purpose of the following chemicals used in industrial waste treatment:

3.1 Hydrogen Sulphide

3.2 Carbon Dioxide

3.3 Chromium

3.4 Carbon Monoxide

Electrical properties were determined for a new material called dragonite which is considered to be a metallic conductor. It was found that its electrical conductivity is 2.5*10^7 and electron mobility is 0.003 . For dragonite, you can assume a density of 8.1  and an atomic mass of 75.4 .

What is the number of free electrons per atom in this material? Enter your answer as a number to two decimal places.

The selection of dissolution media is considered from :
1. Solubility of active ingredient
2. Stability of active ingredient
3. Sink condition
4. Permeability of active ingredient in digestive tract
A. 1,2,3
B. 1,3
C. 2,4
D.4
E. All correct

Select a system from everyday life that employs feedback control in its operation.

a. Describe the system and how feedback is used.

b. Identify the manipulated variable(s), controlled variable(s) and disturbance variable(s).

a) The K-ratio is used to calculate the equilibrium distribution of a component in a mixture between vapor and liquid phases. It can be determined by using two method.

Determine the K-ratio. For n-octane at 100°C at 0.1 MPa

i) Using Raoult’s Law

ii) using the de Priester chart. (Show the chart in your answer.)

2. Determine the bubble point temperature (lower limit to the flash tank temperature)and the dew point temperature (upper limit to the flash tank temperature) for a mixture of n-hexane, n-heptane, and n-octane in a 0.33:0.33:0.34 molar ratio at 0.1 MPa .

3. For an isothermal flash at 100°C and 0.1 MPa what is the V/F ratio, for the mixture of part b, and what are the compositions of the vapor and liquid products.

a) Discuss the theoretical principles of constant pressure filtration relating it to plate and frame filtration

b) Give the industry application of this type of filter

c) Calculate the specific resistance of the cake (α) and the resistance of the filter medium (Rm) on the basis of the following experimental data for a constant pressure filtration of a suspension of incompressible solids of concentration 30 kg/m3 on a filter medium of area 1 m2 . The pressure drop was 2 bar. The viscosity of the filtrate (η) is 1.1 x 10-3 kg/m/s.

Vol of filtrate V (m3 ) Time t(s)

2.0x10-3 23

4.0 60

6.0 114

8.0 184

10.0 270

A packed bed reactor is 2 m long with 0.2 m diameter. The reactor is filled with 1000 spherical particles with a diameter of 5 mm. Air enters the reactor at a volumetric flow rate of 0.0X m³/s. At these conditions, density of air is 1.2 kg/m3 with a viscosity y of 3.0 x 10^-5 Pa.s. Calculate:

- Porosity of the bed reactor.

- The gas mass velocity, G.

- Re number, at this value of Re would kinetics or viscous effect dominate the pressure drop?

- Pressure drop across the reactor.

x=1

Estimated required time to solve the question: 15 minutes

The elementary liquid phase reaction

A + B C

is carried out in a 550 dm3 reactor. The entering concentrations of streams A and B are both 2-molar and the specific reaction rate is 0.015 dm3/(mol*min).

1.1 Calculate the time to reach 80%conversion if the reactor is a batch reactor filled to the brim.
1.2 Assuming a stoichiometric feed (10 mol A/min) to a continuous flow reactor, calculate the reactor volume and space-time to achieve 80% conversion if the reactor is

1.2.1 CSTR 1.2.2 PFR
1.3 Redo questions 1.1 and 1.2 assuming the reaction is first-order in B and zero-order in A with k = 0.015 /min.
1.4 Assume the reaction is reversible with Ke = 2 dm3/mol. Calculate the equilibrium conversion and the CSTR and PFR volumes necessary to achieve 98% of the equilibrium conversion.

Give three examples of applications in which adsorption is preferable to cryogenic separation, and briefly explain why.