The use of flow models for design of plant operating procedures

The report describe a systematic approach to the design of operating procedures or sequence automatics for process plant control. It is shown how flow models representing the topology of mass and energy flows on different levels of function provide plant information which is important for the considered design problem. The modelling methodology leads to the definition of three categories of control tasks. Two tasks relate to the regulation and control of changes of levels and flows of mass and energy in a system within a defined mode of operation. The third type relate to the control actions necessary for switching operations involved in changes of operating mode. These control tasks are identified for a given plant as part of the flow modelling activity. It is discussed how the flow model deal with the problem of assigning control task precedence in time eg. during start-up or shut-down operations. The method may be a basis for providing automated procedure support to the operator in unforeseen situations or may be a tool for control design. (auth.)