Process for controlling the process of crystallisation from sucrose solutions

摘要

The process of crystallisation from sucrose solutions is controlled with the aid of certain values measured in the sucrose solution or crystal suspension, e.g. viscosity or consistency, density, conductivity, permittivity, boiling point elevation and the like. A technologically optimal process control is to be ensured by an expedient linkage of simultaneously measured physical variables while changing the process conditions. An uncontrolled supersaturation of the sugar solution or an unwanted slowing down of crystal growth is achieved by using as control variable for the addition of undersaturated sucrose solution to the evaporating crystalliser after the seeding the conductivity or permittivity measured at a viscosity of 150-250 mPa.s or at a density of 1370-1420 kg/m3, and subsequently the viscosity or density, until a viscosity of 200-500 mPa.s or a density of 1390-1480 kg/m3 is reached. The process can be applied to the production of crystalline sugar from sucrose solutions.