**Author details**

Airam Sausen, Paulo Sausen, Mauricio de Campos *Master's Program in Mathematical Modeling (MMM), Group of Industrial Automation and Control, Regional University of Northwestern Rio Grande do Sul State (UNIJUÍ), Ijuí, Brazil.*

#### **7. References**

14 Will-be-set-by-IN-TECH

**Figure 13.** Liquid output flow rate variations *mLS*,*out*(*t*), (a) level control strategy PI conventional (dashed line) and level control strategy PI by band (solid line), (b) level control strategy PI conventional

this difference is minimal, according to Figures 11 (a) and (b), Figures 13 (a) and (b). For both controllers simulation results of the liquid output flow rate are better than the results obtained with the level control strategy PI conventional. Considering the liquid output flow rate when the level is within the band, both processes (i.e., level control strategy PI and error-squared

In this chapter with objective of reducing the export oscillatory flow rate caused by slug flow, three methodologies of the level controls were implemented (1) level control strategy PI conventional; (2) level control strategy PI in the methodology by bands; (3) error-squared

The simulation results showed that the error-squared level control PI strategy in the methodology for bands presented the better results when compared with the level control strategy PI conventional, because reduced flow fluctuations caused by slug flow; and with the level control strategy PI in the methodology by bands, it probably happened because the first

As suggestions for future work new control strategies can be implemented in integrated system, i.e., more than one valve simultaneously. Considering the mathematical modeling of the process, it was necessary to investigate a mathematical model with fewer parameters, along with the construction of an experimental platform, since the data of a real process is

*Master's Program in Mathematical Modeling (MMM), Group of Industrial Automation and Control,*

*Regional University of Northwestern Rio Grande do Sul State (UNIJUÍ), Ijuí, Brazil.*

(dashed line) and error-squared level control strategy PI by band (solid line), *z* = 20%.

level control strategy PI both in the methodology by band) have similar trends.

output flowrate [kg/s]

<sup>0</sup> <sup>50</sup> <sup>100</sup> <sup>150</sup> <sup>200</sup> <sup>250</sup> <sup>300</sup> <sup>350</sup> <sup>400</sup> <sup>0</sup>

Output flowrate variations with PI conventional level controller. Output flowrate variations with error−squared PI level controller by bands.

time [min] − (b)

<sup>0</sup> <sup>50</sup> <sup>100</sup> <sup>150</sup> <sup>200</sup> <sup>250</sup> <sup>300</sup> <sup>350</sup> <sup>400</sup> <sup>0</sup>

Output flowrate variations with PI conventional level controller. Output flowrate variations with PI level controller by bands.

time [min] − (a)

level control strategy PI in the methodology by bands.

difficult to obtain and are not provided by oil industry.

Airam Sausen, Paulo Sausen, Mauricio de Campos

has highly respected the defined bands.

**6. Conclusion**

**Author details**

output flowrate [kg/s]

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	- [20] Storkaas, E., Skogestad, S. & Godhan, J. M. [2003]. A low-dimensional dynamic model of severe slugging for control design and analysis, *11th International Conference on Multiphase flow (Multiphase03)*, San Remo, Italy, pp. 117–133.
	- [21] Tengesdal, J. O. [2002]. *Investigation of self-lifting concept for severe slugging elimination in deep-water pipeline/riser systems*, Phd thesis, The Pennsylvania State University, Pennsylvania.
	- [22] Thomas, P. [1999]. *Simulation of Industrial Processes for Control Engineers*, Butterworth heinemann.
