Patent ID: 7366582

Claim:
A method for controlling an electrolytic process in an electrolytic plant, in which method process statuses are interpreted on the basis of physical and chemical measurements, and electrolytic process control parameters are adjusted in order to prevent and eliminate fault situations, wherein process and control data collected from the process in a long time span is transformed into mathematical models and inference algorithms, which are recorded in computer memory, periodically and regularly during the process, there are calculated, by means of the created models and inference algorithms as well as real-time process measurement data, one or several indexes describing process status, in which case a theoretical cell voltage at a known point of time is defined by means of process measurements and an empirical model, a real cell voltage is measured at said point of time, the difference between the theoretical and real voltages is calculated, and a difference value and said point of time are recorded in the computer memory, and there is formed a trend of the difference, the trend of the difference in the voltages is interpreted by means of a mathematical model, the interpretation of the trend of the difference is transformed, individually for each cell, into a status index describing momentary status of the process by means of fuzzy and logic inference algorithms, and when one or several of the calculated indexes deviate from predetermined values, the process control parameters are adjusted for controlling the process.