State and Parameter Estimation for a Gas-Liquid Cylindrical Cyclone

The development and production of hydrocarbons from oil and gas discoveries in deep water require cost-efficient compact separation technology. However, the small operational volume of compact separators make them highly sensitive to changes in flow rate and composition. Therefore, measurements of critical variables are crucial for providing operators with the necessary insight, as well as enabling the use of advanced controllers to efficiently control such separators. Available measurements are, however, often limited due to high investment cost or lack of suitable sensor technology. Estimators (soft sensors) can alleviate this problem. The gas-liquid cylindrical cyclone is a type of compact separator recently considered for subsea application. Several advanced controllers have recently been derived for this separator, but estimators are needed for implementation in subsea applications. Therefore, in this paper, we develop and study the performance of the UKF and MHE estimators providing state feedback to a linear MPC.