A hydrogen filling station system is made out of hydrogen pressurized buffer vessels which successively balance with the vehicle tank to be filled. If required, a compressor may be used in order to increase buffers and vehicle tank pressures, and gas may be cooled to increase the filling speed.
Although the system is simple, all operations are inherently transient and filling constraints are numerous. Constraints may be dictated by customer requirements (i.e. maximum filling time, consecutive numbers of vehicles to fill) and by materials limits (i.e. minimum and maximum temperatures on the vehicle tanks). In addition technology and economy issues are also part of the problematic. Designing and rating such type of a process becomes then complex. In order to cope with this design problem, a complete general purpose dynamic model of a hydrogen filling station has been developed using appropriate customization capabilities of Aspen Hysys Dynamics (tm). The model comprises representation for typical equipments like vessels, compressors, heat exchangers and valves, and includes a detailed radial heat transfer dynamic model for vehicle vessels. As a result, it gives a complete workable tool with an instinctive interface and possibility to analyze real time charts.
The use of the model during different phases of a real project is illustrated. It is shown how such kind of tool becomes of great help not only for process equipment sizing and operation but also when regulatory and sequential control needs to be optimized.