How much dry sugar must be added in 100 kg of aqueous sugar solution in order to increase its concentration from 20% to 50% ?

1.How much dry sugar must be added in 100 kg of aqueous sugar solution in order to increase its concentration from 20% to 50% ?

Solution:

Step-1:The process diagram

100kg,20%    →            mixing                      →  Y ,50%

                                             ↑

                                      S, 100%

Step-2:

Overall mass balance

100 + S = Y                                                                               (1)

Overall solid balance

0.20*100 + S = 0.5*Y

or, 20 + S = 0.5 (100 + S)

or, S – 0.5 S = 50 – 20

or, 0.5S = 30

S=  =60

From (1) we get,

100 + 60 = Y

Y = 160

Therefore, 60kg of dry sugar added to increase its concentration from 20% to 50%.

S=sugar,Y=result

Notes: If problems to understand the process diagram ,Then comments here...Thank you.