Computer Control of White Sugar Refining Process

Control of the white sugar vacuum pan has proven to be an ideal application for process control computers. The computer is well suited to perform this function because of the batch nature of the process, and has been used to augment a complete analog control system. Each strike requires detailed sequencing and precise monitoring of process variables in order to maintain product quality while increasing plant efficiency. For pans equipped with mechanical circulators, an additional improvement results when the current load of the circulator motor is used as the measure of consistency. Further, the computer is able to duplicate the control sequencing on multiple units through the use of separate setpoint arrays, determined for each particular pan and type of strike being boiled. The primary improvement is the reduction of time per strike, leading directly to increased output. The computer also helps to minimize downtime by constantly monitoring alarm conditions and taking corrective action when necessary to avoid emergency situations such as solidifying the massecuite in the pan. Preliminary results have shown an immediate increase in refinery production as a result of installation of the process control computer.