Multiple bases

Some flowsheet units may not behave in a linear fashion over their entire operating range. For these units it may be is necessary to have several different Base + Delta models. Each of these is independent and used to model behaviour under different operating conditions. For example, a thermocracker may require two different models to reflect the differing levels of conversion depending on the severity of the cracking. A single variable must be defined which is used to indicate which particular Base + Delta model is used by the processing application. This variable must be one of the Input parameters. In the case of the thermocracker temperature would be included as an Operational Parameter, and this would be used to switch between different bases.