Observer based safe operation of the 13 C cryogenic separation column

The cryogenic 13 C separation process is very slow, the concentration of this isotope reaches the desired value during weeks. A lot of variables, essential for the separation process must be controlled, so that any malfunction can compromise the whole production. The most important information about the system state is given by the carbon monoxide level sensor, with disastrous consequences by its failure (conductor breaking, power line failure, etc.). The authors try to solve this problem using an observer which generates the observed level information and compare, in normal mode of operation, the observed value with the real, measured variable. By sensor failure, the expected difference will increase drastically and the control system will switch to the observed level information.