Operative relationship of a CHC without attrition
Irrespective of the crystal size, the rate of increase in mass is:
Therefore:
However (see section 4.2.7):
The crystallizer’s productivity is:
The nucleation rate is equal to the productivity quotient (in kg.s-1) by the mean crystal mass (see section 4.2.7).
However, we frequently write:
e : agitation power per cubic meter of slurry (W.m-3).
By equating the two expressions of J, we obtain:
Let us replace AX with its value in the expression of P:
Or again:
Lifting the two members of the previous equation to power i = — comes
g
to:
However, the Mc / P ratio is written:
By eliminating P between [4. Ibis] and [4.2], we obtain the desired relationship:
In general, j is close to i, and Mc scarcely intervenes in the equation [4.3]. Often, the value of i, greater than 1, is of the order of 2 and we have:
We observe that the crystal size is far from proportional to the residence time. This can be explained by the supersaturation AX decreasing with residence time.
