Nucleation of lactose using continuous orifice flow

This paper describes two methods used to produce a constant supply of super-saturated lactose solution with nuclei already present, required as the feed stream for a new design of a continuous crystalliser. Both methods involve cooling a hot saturated lactose solution to super-saturation and then passing it through an orifice or applying mechanical agitation to initiate nucleation. Orifice Reynolds number (Re) of 500 and 1000 and wait times subsequent to cooling of 0 and 1 h were used. Wait time and Re had no effect on nuclei numbers, but a wait time at an orifice Re of 1000 increased crystal size and decreased the span of the crystal size distribution, suggesting that these conditions produced faster growing crystals. In experiments with nucleation by mechanical agitation followed by dilution, crystal numbers were several orders of magnitude lower than for orifice nucleation, and resulted in a small span.