Engineering Answers

Methanol (M) is to be separated from water (W) by atmospheric distillation. The feed contains 22 kg/hr methanol and 25 kg/hr water. The distillate contains 90 mol% methanol and the bottom product contains 5 mol% of methanol. The feed is saturated. Calculate the molar flow rates of methanol and water in the bottom and distillate product stream.

200 kg/min of feed are fed to a continuous distillation column. The stream contains

70 kg /min NaOH and the difference is water. The distillate flows out of the column at

90 kg /min and contains 4 kg /min NaOH. Determine the bottom stream mass flow

rate and the composition of all streams. Draw and label the flowchart.

explain the importance of using a range of accurate design reference materials when developing design proposals

A packed counter-current water cooling tower is used to cool

1.356 kg/s.m2

of water from 43.3 °C to 26.7 ºC. The air enters from the bottom

of the tower at 23.9 ºC with a wet bulb temperature of 21.1 ºC. The whole of the

resistance to heat and mass transfer can be considered as being within the gas

phase and the product of the mass transfer coefficient and the transfer surface

per unit volume of column (KG.a) may be taken as 1.207×10-7

kmol/s.m3

.Pa.

The tower operates at atmospheric pressure. Calculate the minimum air flowrate

and the necessary height of the tower when 1.5 times of minimum is used as

actual air flowrate.

Data: Latent heat of water at 0 ºC = 2501 kJ/ kg

Heat capacity of dry air = 1.005 kJ/ kg. ºC

Heat capacity of water vapour = 1.88 kJ/ kg. ºC

Density of air = 1.198 kg/ m3

Enthalpy of saturated air-water vapour data are as follows:

Hyi, kJ/kg dry air 84 97.2 112.1 128.9 148.2 172.1 197.2

Temperature, ºC 26.7 29.4 32.2 35 37.8 40.6 43.3

A 30-plate bubble cap column is to be used to remove n-pentane

from oil by means of pure steam stripping. The inlet oil contains 6% n-pentane

by volume and it is desired to reduce the n-pentane to 0.1% by volume. Assume

isothermal operation and an overall plate efficiency of 30%. Find out the ratio

of actual to minimum steam consumption. The equilibrium relation for the

system is y=3x.

In a crank and slotted lever quick return mechanism, as shown in Figure, the driving crank length

is 75 mm. The distance between the fixed centers is 200 mm and the length of the slotted lever is

500 mm.

PET has a Young's, Modulus of 3.5 GPa and PLGA 1.2 GPa. A polymer blend is prepared with 45:55 mixture (PET:PlGA) . What is the Young's, Modulus of this blend (use mixture rule). Calculate the percent load borne by PET when the blend is subjected to a load. If after 10 days, entire PET had degraded, what is the Young's Modulus of this blend.

1. Two heating units A and B are connected in parallel across 120 volts supply. Unit B takes twice as much power as A and the total power is 2160 watts. Determine the resistance of A and B in ohms. 

The shaft of a steam turbine produces 600 Nm torque at 50rev/s. Calculate the work transfer rate from the steam

The viscosity of a fluid is to be measured by a viscometer constructed of two 3m long concentric cylinders. the inner diameter of the outer cylinder is 35cm, and the gab between the two cylinders is 0.14m.the outer cylinder is rotated at 250rpm and the torque is measured to be 1.8N determine the viscosity of fluid