bkc3492 - unit operation ii 21112

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I

Unversit i

Malaysia

P A H A N G

ngu i i i ng

r e a t J v I y

FACULTY OF CHEM ICAL & NATURAL RESOU RCES ENGINEERING

FINAL EXAMINATION

COURSE

NIT OPER ATION II

COURSE CODE

KC3492

L E C T U R E R

A Y DE R A B DU L B A R

ANWARUDDIN HISYAM

AIIMAD ZIAD SIJLAIMAN

D ATE

6 JUN E 2012

D URATION

HOURS

SESSION/SEMESTER :

ESSION 2011/2012 SEME STER II

P R O G R A M E C O DE

K C

INSTRUCTIONS TO CANDIDATE:

1 his question paper consists of FOUR 4) questions Answer ALL

questions.

2 A ll answers to a new q uest ion should s tar t on new page .

3

All the calculations and assumptions must be clearly stated.

4

Candidates are not al lowed to br ing any m ater ial other than those al lowed

by the invigilator into the examination room.

EXAM INATION REQUIREMEN TS:

1. TEXT BOOK -

G eankopl is , C.J ., Transport Pro cesses and Separation Process

P rinciples , P rentice Hall , 2003

DO N O T T U R N T H I S P A G E U N T IL Y O U A R E T O L D T O DO S O

This examination paper co nsis ts of

FIVE (5)

printed pages including front page.


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CONFIDENTIAL

KC/111211/BKC3492

Q U E S T I O N 1

W et solids pass through a continuous dryer. Hot dry a ir enters the dryer at a rate of 300

kg/min and takes up the w ater that evaporates from the solids. Hum id air leaves the

dryer at

5 C

containing 2.5 wt water vapor. The pressure is constant at 1 atm

thorough the system.

a) W hat is the rate of water in kg/min evaporating in the dryer?

4 M arks )

b Estimate the wet-bulb temperature, relative humidity, dew point, and specific

enthalpy of the air leaving the dryer.

6 Mark s )

c If a condenser is installed after the dryer to cool down the humid air to 10C,

estimate the absolute humidity and specific enthalpy of the air leaving the

condenser.

8 M arks )

d) Calculate the rate of condensat ion of water kg/mm) and the heat rate from the

condenser kW).

7 M a r k s )


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KC/11 121I1BKC3492

QUESTION

he relation between flow and head for a certain slurry pump may be represented

approxim ately by a straight l ine, the maximu m flow at zero head being 0.00 15 m

/s and

the maximum head at zero flow 760

in

of liquid.

A sam ple of the s lurry was fi l tered at a constant ra te of 0.00015 m

3

/s through a leaf

filter covered w ith a similar filter cloth but of one -tenth the area o f the full-scale unit,

and after 6 5

s the pressure across the filter was 360

in

of liquid. After a further 480 s

the pressure w as 600

in

of liquid.

Using this pum p to feed pa rticular slurry to a pressure leaf filter:

a How long will i t take to produce 1 m

3

of filtrate?

15 M arks)

b

W hat will be the pressure across the filter after this time?

10 M arks)


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Q U E S T I O N 3

An a dsorption column is used to remove the ferrous from a ferrous sulfate solution with

an initial concentration of 1.0 M and flow rate of 2.52 m

3

/h. The height and diameter of

the adsorption column are 0.18 and 0.03 m respectively.

a) Using the data given in

Table 1;

estimate the break point value and time.

5 Marks)

b) Determ ine the fraction of total capacity used up to the break p oint, including

num erical integration to calculate the area.

6 Marks)

c) Find the length of the unused bed .

7 Marks)

d) If the break point time required for a new column is

4 5

h, calculate the new

total length of the column n eeded .

7 Marks)

Table 1: Adsorption Data Curve

t h) c

0

2

2.5

3

0 0 3

3.5 0.16

4.0 0.40

4.5

0 6 6

5.0

0 9 0

5.1 0.92

5.4 0.98

5.8

0.99


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Q U E S T I O N 4

A 0.015cm thick complete mixing membrane is used to separate two gases. The

permeability of the membrane is 3.9

cm3 STP).cml s.cm2.cmHg) and ideal

separation factor of 0.41. The gas stream is composed of A and B gasses, the

composition of A in the feed is 49.9. The feed side pressure was

0 533 bar and

permeate side was 0.133 bar. Assuming that the feed flow rate is 1998 cm

/s and the

fraction of feed un-permea ted is 0.47, calculate:

a)

The m embrane area, permeate composition and rejection composition.

15 M arks )

b)

The m inimum reject concentration.

10 M arks )

E N D O F Q U E ST IO N P A P E R

bkc3492 - unit operation ii 21112

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