Post on 21-Feb-2018
7/24/2019 QUIZ 1 (1)
1/1
QUIZ 1
UNIT OPERATION
BKF3463
A 10% aqueous solution of NaOH at 37.8C and a flow rate of 13607.78 kg!r is to "e
#on#entrated to $0 wt% " e&a'oration 'ro#ess. A forward feed dou"le effe#t e&a'orator
sste( is used wit! t!e esti(ated o&erall !eat transfer #oeffi#ient of ) 1* +$$3 ,(+.- for
t!e first effe#t and )+* 186 ,(+.- for t!e se#ond effe#t. /!e "oiling 'oint rise and !eat of
solution #an "e #onsidered negligi"le. /!e &a'or s'a#e 'ressure of t!e se#ond effe#t is
3.38ka and t!e saturated stea( enters t!e first effe#t at 8+$. ka. /!e !eating area is
assu(ed to "e equal.
a Cal#ulate t!e a(ount of liquid and &a'or 'rodu#t fro( ea#! effe#t and t!e stea(
#onsu('tion in kg!r.(The difference between the assumed and exact values should
not be more than 10%)
(32 Marks)
b) Cal#ulate t!e rate of !eat transfer and !eat transfer area of ea#! effe#t. (The difference
between the average and exact values should not be more than 15%) (6 Marks)
# ,!at will !a''en to t!e e&a'oration sste( if t!e &a'or 'ressure in t!e se#ond effe#t
is in#reased +$ ka2 4'lain our answer.
(2 Marks)