Sugar crystallization control system and method

A method for controlling sugar crystallization in a closed-loop manner, comprising:

• determining a size of sugar crystals in a sugar slurry, wherein the size of the sugar crystals is determined based at least in part on an initial size of the sugar crystals, a supersaturation degree of the sugar slurry, a change in time, and a first tuning parameter;
• determining a consistency value of the sugar slurry, wherein the consistency value of the sugar slurry is determined based at least in part on an initial consistency value of the sugar slurry, the size of the sugar crystals, the supersaturation degree, a level value of the sugar slurry, and a second tuning parameter;
• determining a first brix value of a liquid portion of the sugar slurry, wherein the first brix is determined based at least in part on a second brix of the sugar slurry and the consistency value;
• determining a purity value of the liquid portion of the sugar slurry, wherein the purity value of the liquid portion of the sugar slurry is determined based at least in part on the level value of the sugar slurry, the second brix value of the sugar slurry, a purity value of a syrup supplied to the sugar slurry, an amount of the liquid portion of the sugar slurry, and the first brix value of the liquid portion of the sugar slurry;
• determining the supersaturation degree of the sugar slurry, wherein the supersaturation degree of the sugar slurry is determined based at least in part on a sugar saturation point of the sugar slurry, the first brix value of the liquid portion of the sugar slurry, and the purity value of the liquid portion of the sugar slurry;
• and
• controlling a syrup feed valve position, a steam valve position, a vacuum pressure, or any combination thereof based on the supersaturation degree.

A method for controlling sugar crystallization, comprising, during a sugar crystallization process;

• determining a first brix value of a liquid portion of a sugar slurry, wherein the first brix value describes sugar content of the liquid portion of the sugar slurry;
• determining a first purity value of the liquid portion of the sugar slurry, wherein the first purity value describes weight percentage of sugar among solids dissolved in the liquid portion of the sugar slurry;
• determining a supersaturation degree of a sugar slurry based at least in part on the first brix value and the first purity value;
• and
• regulating temperature of the sugar slurry in a closed-loop manner to maintain the supersaturation degree of the sugar slurry below a threshold.

A system configured to control sugar crystallization, comprising:

• a sugar processing subsystem configured to hold a sugar slurry, to add heat to the sugar slurry, and to add syrup to the sugar slurry;
• a brix measuring device configured measure a first brix value of the sugar slurry;
• a temperature sensor configured to measure a temperature of the sugar slurry;
• and
• structure for determining purity of the liquid portion of the sugar slurry during the sugar processing;
• a batch crystallization controller configured to:
• determine a supersaturation degree of the sugar slurry in a closed-loop manner, wherein the supersaturation degree is based at least in part on a sugar saturation point of the sugar slurry, a second brix value of a liquid portion of the sugar slurry, and a purity of the liquid portion of the sugar slurry, wherein the second brix value and the purity of the liquid portion of the sugar slurry are determined based at least in part on the first brix value of the sugar slurry;
• and
• regulate influx of syrup added to the sugar slurry, the temperature of the sugar slurry, or both based on the supersaturation degree of the sugar slurry.