Process for automatically operating a continuous crystallization apparatus for producing sugar.

摘要

1. Process for automatically operating a continuously operating apparatus for crystallization by evaporation for producing sugar consisting of a closed horizontal vessel divided by vertical partitions into several compartments fitted with a heating bundle, a sugar solution being introduced into each compartment, a magma made up of a mixture of small crystals and mother liquor being introduced into the first compartment and the massecuite produced being withdrawn from the last compartment, characterized by the fact that the following operations are periodically carried out : for each "i" index compartment the optimal value of a parameter selected from a first group of five parameters constituted by the ratio of the sugar solution flow-rate fed to the compartments to the total flow-rate of sugar solution to the processed (YEGi), the ratio of the flow-rate of the water evaporated in the compartments to the total flow-rate of the water evaporated in the crystallization apparatus (YEVi), the ratio of the flow-rate of the massecuite coming from the compartments to the total flow-rate of the massecuite produced (YMCi), the brix of the massecuite in the compartments (BMCi) and the sugar crystal content of the massecuite in the compartments (RDTi) is determined, using a pre-established law giving the value of the said parameter in the compartments according to the brix of the sugar solution to be processed (BEGT), the steam pressure in the vapor space of the crystallization apparatus (PCAL) and the ratio : R = (QMAG x RDTMAG)/(QEGT x BEGT) where QMAG : magma flow-rate RDTMAG : crystal content in magma QEGT : total flow-rate of the sugar solution to be processed BEGT : brix of the sugar solution to be processed, the optimal value of a first operation parameter (PVAP-heating steam pressure-or QEGT) is calculated using for this calculation the optimal value determined for the said parameter of the first group, the imposed values of a second operation parameter (QEGT or PVAP) and of a parameter of a second group (resulting status parameter) constituted by the total flow-rate of the evaporated water (QEV), the total flow-rate of the massecuite produced (QMC), the brix of the massecuite produced (BMC) and the crystal content of the massecuite produced (RDT) and, possibly, a corrective factor the value of which depends on the difference between the imposed value of the said parameter of the second group and the measured value of the latter, and the said first operation parameter is adjusted to maintain the same at a set value equal to the optimal value calculated for this parameter.