The application of dynamic matrix control to a olefines plant

The key user of ethylene refrigerant is the demethaniser column and the application of dynamic matrix control (DMC) to the plant is illustrated by the application to this column. The basic plant control is such that the propylene refrigerant flow to the reboiler is used to control the temperature on a tray in the lower part of the column. The reflux rate is used to control the ethylene content of the methane overhead product stream. What is required is a control system which will achieve satisfactory composition control of the column subject to the column hydraulic and refrigeration compressor power limitations. DMC is a control technique which is ideal for such a problem