In the offshore oil and gas industry, treating produced water, which contains contaminants extracted alongside oil and gas from reservoirs, before it can be safely disposed of or reused is essential. Integrating hydrocyclone systems with three-phase separators significantly improves the efficiency of separating the oil, water, and gas components, thereby ensuring compliance with environmental regulations and reducing operational costs. Consequently, the developed of an optimally coordinated control solution for these integrated systems offers benefits such as enhanced efficiency, cost reduction, regulatory compliance, and improved sustainability. This paper focuses on a comparative study of three control design methodologies: an optimized–PI controller, a model reference adaptive controller (MRAC), and a newly developed Immersion and Invariance (I&I) adaptive controller for offshore produced water treatment. These control strategies are evaluated for their effectiveness in regulating key parameters, such as the pressure drop ratios (PDR) and the water level (L) in the presence of parametric uncertainty and external disturbance. The superior performance of the proposed I&I controller is demonstrated via simulations and analysis.

As the hydrocarbon discharge regulation is becoming more stringent, and emerging sensing and digitization technologies are applied in offshore oil and gas (OG) production, it is beneficial to upgrade the existing control systems by integrating these new measurements/information into the control loops. To achieve this goal, some proper control-oriented models need to be developed. Hydrocyclone-based de-oiling systems are commonly used in the produced water treatment after the three-phase separators in offshore OG production. Control-oriented modeling of these systems has proven a challenging task. In this paper, a system identification approach is taken and polynomial-type Hammerstein-Wiener (HW) models of the separation efficiency are identified for a de-oiling hydrocyclone system using the newly installed online oil-in-water (OiW) measurement. An exhaustive search is used to determine the order of the polynomials and transfer functions. The best model found was a Hammerstein model. The model obtained provides the opportunity to extend the existing de-oiling control framework to include the OiW measurement into feedback loops.

With the objective of pursuing eco-friendly and environmentally sustainable extraction in offshore oil and gas production, the Produced Water (PW) treatment is inescapable whether for reinjecting the PW back to the reservoir with the purpose of enhancing oil recovery or discharging it into the ocean. The de-oiling technology based on the hydrocyclones system connected to the three-phase separator is generally employed for the PW treatment. In order to boost the effectiveness of the interconnected de-oiling systems, it is crucial to introduce an advanced coordinated controller for the separators and hydrocyclone systems with regard to the uncertainties and unknown disruptions that occur during dynamic operations. This research suggests a robust Multivariate Model Reference Adaptive Control (MRAC) approach, in order to regulate the Pressure-Drop-Ratio (PDR) of the hydrocyclone and the water level in the separator simultaneously. The suggested control technique is expressed within a framework of state feedback output tracking MRAC by taking adaptive disturbance rejection into account. Furthermore, a control parametrizing obtained from a factorization of the High-Frequency Gain Matrix (HFGM) in the shape of the product of three matrices, i.e. LDS decomposition, is employed in the designing procedure to relax restrictive conditions about the HFGM. Finally, the proposed robust MRAC method is tested on a lab-scaled PW application, and the simulation outcomes explicitly establish the effectiveness and also its remarkable performance of the suggested control strategy.

This study presents a non-inverting transformer-less Boost converter with a higher voltage conversion ratio, resulting in quadratic growth of the output voltage with modest increments in the duty cycle rate. The continuous input current of this converter simplifies the input filter design and enhances fuel cells' lifetime and stability. Additionally, compared to existing architectures, this converter reduces the voltage and current stresses on semiconductor components, making it a promising alternative to other quadratic Boost converters. As a result, this topology appears to be a viable alternative for the remaining quadratic Boost converters. The inclusion of common-ground switches, which eliminate the need for additional components for gate driver isolation, is one of the main features that make this topology distinct. As a result, the converter fabrication cost and size are reduced. The proposed converter's steady-state analysis is thoroughly explained. Stresses placed on semiconductor devices. Then, a meaningful comparison between the proposed circuit and its counterparts is provided to understand this converter's unique attributes.