# Systems' simulation

Optimisation des énergies et émissions

## Dynamic simulation: visualize the impact of a given decision

Simulation can be seen as a method of solving problems by trial and error. It involves using calculations to mimic the behavior of a physical system, providing a kind of virtual experimentation. The fundamental idea is to visualize the impact of a given decision, through a series of calculations, rather than in reality. With this definition, we can imagine simulation as a succession of manual calculations; the role of computers is simply to speed up the process thanks to their computing power.

Although simulation can be carried out with very simple tools such as Excel spreadsheets, it is clear that beyond a certain level of complexity, more elaborate tools become necessary.

There are 2 typical situations which give rise to complex behaviors in real life:

• Complex relationships : the case where there are complex relationships between the different components of a system: this is the case when there are a large number of degrees of freedom at all stages of the system, and the possible evolution (and therefore the right decisions) at a given moment depends strongly on the decisions taken at other stages.
• Uncertainties: the case where some level of uncertainty exists in the system; here the complexity comes from the interaction between the deterministic and the random parts of the system

PRINCEPS’ software deals with the first sub-type of complex systems.

### Both situations exist in industrial systems

If we focus on the first kind of complexity, i.e. the complexity of physical systems can also be subdivided into 2 sources:

• #### Simple behavior of each component but complex interactions due to the numerous interrelations in the overall structure

• Princeps approach is rather interested in the system's simulation as a whole with an overall calculation of the flow of materials, storage levels, material and product movements .

### The special case of refinery simulation

Refinery simulation is considered as one particular application of the dynamic systems simulation engine developed by PRINCEPS.

PRINCEPS simulation engine is a generic one. It handles both discrete and continuous time simulation, and allows local constraint solving and relations definition and propagation.
Within this context, refinery simulation is made possible through a “refining toolbox”. The generic capabilities implemented in the simulation engine are adapted through the refining toolbox and turn into specialized features such as:

• Automatic adjustment of events duration in order to keep tank levels within the limits
• Maintaining consistency between different events through relation definition and propagation. In the context of refinery simulation, this can be insuring consistency between types of feeds or operating parameters to various processes, to take an example

### See Refinery simulation at work

This would be the best way for you to get a good idea about how our products can help you achieve refinery scheduling in production conditions.