Mill Material Balance

Basic Approach of Miling IV-1

CHAPTER IV

BASIC APPROACH OF MILLING

After we know technically the composition of sugar cane as the raw material for the milling,

then it is now come to the basic approach of milling and its mass flow from a mill unit4) outlined

below:

cane bagasse

mixed juice

The formula of continuity:

input = output

At the input portion, for mill#1 is cane, or bagasse for the following mill units.

Let : Wim = the weight, and

Vim = the volume (no-void)

At the output portion, there are juice (extracted) and bagasse.

Say : Wej = the weight of extracted juice

Vej = the volume of extracted juice

For the bagasse: Wb = the weight, and

Vb = the volume (no-void);

Hence : Wim = Wej + Wb .................................... (1)

Furthermore, if: dim = cane / bagasse density (no-void) at the input portion

dej = density of extracted juice, and

db = density of bagasse (no-void) at the output portion

then : Wim = dim x Vim

Wej = dej x Vej

and : Wb = db x Vb

4) Tot Soemohandojo, Extraction of a Mill, Gula Indonesia Magazine, Volume VI No.4 - 1980

Mill Material Balance

Basic Approach of Miling IV-2

Because cane / bagasse at the input portion is considered to consist of juice and fiber as

mentioned in Chapter II, and if:

Wij = the weight of juice contain in cane / bagasse

Vij = the volume of juice contain in cane / bagasse

and : Wf = the weight of fiber

Vf = the volume of fiber (no-void);

then : Wim = Wij + Wf .................................. (2)

Furthermore, if:

dij = density of juice containing the input portion, and

df = density of fiber (no-void)

then : Wij = dij x Vij

and : Wf = df x Vf

The identical condition applies to the output portion, that bagasse is considered to consist of

juice and fiber (see Chapter II), then if:

Wbj = weight of juice in bagasse

Vbj = volume of juice in bagasse

Wf = weight of fiber, and

Vf = volume of fiber (no-void), as mentioned above,

And so : Wb = Wbj + Wf ...................................... (3)

It is understood that the weight of fiber (Wf) at the input portion as well as at the output portion

{see equation (2) and equation (3)}, both have the same value (without loss). The same para-

meter also applied to its no-void volume of fiber (Vf).

Then it is also understood throughout the tandem in every mill, that the weight and the no-void

volume of fiber each have the same respective value.