Milk standardization basics
1. 160 kg of 40% cream to standardize to 32% cream, how much skimmed milk should be added?Mass Balance Approach
let x = kg skimmilky = kg of 32% cream
Mass Balance (mass into the process = mass out of the process) 160 + x = y
Component Balance for Fat (fat into the process = fat out of the process)
.40 (160) = .32 (y) which says 40% of 160 kg comes in and 32% of y goes out
.40 (160) = .32(160+ x) substituting our equation for y
.32x = 64 - 51.2
x = 40 kg skimmilk--------------------------------------------------------------------------------
2. How much cream at 35% fat should be added to 500 kg of milk at 4% fat to obtain cream at 10% fat?Mass balance approach
let x = kg 35% creamy = kg of 10% cream
Mass Balance x + 500 = y mass in = mass out
Component Balance for Fat
x (.35) + 500 (.04) = y (.10) again, fat in = fat out
x (.35) + 20 = x(.10) + 50
25 x = 30
x = 120 kg of 35% cream
Pearson square approach to above problem
A shortcut for 2-component mass balances
Place desired percentage in the centre of a rectangle
Place percentage composition of two available streams in left corners of rectangle
Cross subtract lower from higher numbers for right corners of triangle (higher number - lower number)
Use right corners as ratios of two streams
Using the above problem:Component ...................................Mass
35 ................... 6
............10 .........
4 .....................25............................ 500
....................--------..........................-------
........................31
35% cream = 500 x 6 = 120 kg
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............................25