The paper presents a case study on development and implementation of the operator training system for a green-field Hydrocracker unit at a large North American refinery. The users wanted a realistic simulation for operator training and automation design validation. However, the project schedule was compressed and the refinery staff had no experience with developing or maintaining simulators. The challenge of the project team was to find an appropriate balance between a simple simulation model and sophisticated unit operations modeling that mirrored the real process. The solution for this challenge was in the use of a commercially available simulation package designed for operator training, with flexible high-fidelity modeling objects. For instance, the pressure-flow functions for the closed gas track of the unit, implemented using basic simulator, were augmented with models of the compressors and a simple reactor kinetics, taking into account the reactor topology and holdups. The separation block of the unit was simulated using a high fidelity distillation objects, integrated with the process simulator. The distillation package provided simulation of such features, as a real world pressure control for various configurations of the column overhead, weeping at the trays, and “heat shock” in the reboiler. The simulator was successfully used for the plant operator training before the unit start up, as ongoing tool for training in the critical situations (reactor temperature runaways, equipment and control loop malfunctions, e.t.c.), and for testing, tuning and fixing the errors of the DCS control strategies. Customer has used the simulator to find hidden issues in the control strategies that would cause unscheduled downtime as well as certify the operators on the control of the unit.
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