Tutorial Mass Balance I

1. A stream containing four components flows at a rate of 984.0 kg/hr into a separator. The

separator produces two streams of differing compositions. The upper product stream has

a composition of 16.5 % w/w A and 40.9 %

w/w B with C and D making up the remainder.

The lower product stream contains all four components but only the weight percentages

of B and C are known. All available data is presented below. Calculate the compositions

and flow rates of the two product streams.

A 16.5 % w/w

B 40.9 % w/w

C

984.0 kg/h D

Separator

A 14.0 % w/w A

B 36.1 % w/w B 20.9 % w/w

C 23.6 % w/w C 37.6 % w/w

D 26.3 % w/w D

2. Wet paper pulp contains 36 % w/w water. This pulp is to be processed in a drier (i.e water is

to be removed) to produce a pulp containing 11 % w/w water. If the wet pulp enters the drier

at a rate of 3524 kg/h, calculate the production rate of the dried pulp and the rate of removal

of water (kg/h) ?

3. The spent acid from a nitrating process contains 43.0 % w/w H2SO4, 36.0 %

w/w HNO3,

balance H2O. This acid to be strengthened for re-use by the addition of concentrated

sulphuric acid (91.0 % w/w H2SO4, balance H2O) and concentrated nitric acid (88.0 %

w/w

HNO3, balance H2O). The resulting mixed acid is to contain 40.0 % w/w H2SO4 and 43.0 %

w/w HNO3. Calculate the quantities (kg) of spent and concentrated acids which should be

mixed to yield 1000.0 kg of mixed acid.