Cassiano Ranzan

Fast Offshore Wells Model (FOWM): A practical dynamic model for multiphase oil production systems in deepwater and ultra-deepwater scenarios

Abstract This work describes a simplified dynamic model for control and real time applications in offshore deepwater and ultra-deepwater petroleum production systems. Literature about simplified dynamical models, capable of cover the global architecture of an offshore multiphase production system, is scarce. Hence, the proposed model integrates and adapts partial models available in the literature in order to generate a single model of the whole system. The model, designed to represent slugs generated by the casing heading and terrain/riser concomitantly, was evaluated by comparison with a traditional commercial simulator and was also implemented in two actual production systems. As a result, the model showed the capability of capturing complex dynamical behaviors, such as limit cycles, demonstrated to be numerically more stable than similar models in literature, fast enough to be used in real time applications and proved to be adherent to the commercial simulator and actual operating data from Petrobras production systems.

Evaluation of wavelength selection methods for 2D fluorescence spectra applied to bioprocesses characterization

In biotechnological processes, the productivity and costs depend strongly on the control of the operating conditions. For this reason, sensors that allow the monitoring of variables of interest become quite important. 2D fluorescence spectroscopy is one promising option among those that are being applied for this purpose. In the present work, three methods were evaluated to select the best excitation/emission wavelength pairs of 2D fluorescence spectra to infer product, substrate and cellular concentrations throughout a fermentation using a multiple linear chemometric model: Exhaustive Search (ES), Stepwise Regression and Genetic Algorithm (GA). The Stepwise Regression presented unsatisfying results, while GA always led to good R2 values in short computational times. However, for the proposed problem, the ES showed the best performance, finding the global optimum in a few minutes.

Fluorescence Spectroscopy as a Tool for Ethanol Fermentation On-line Monitoring

Abstract In this work the technique of fluorescence spectroscopy was investigated as a tool to measure the main variables of interest in the production of ethanol from sugarcane juice. In order to do that, a methodology for the construction of chemometric models based on the intensities presented by excitation/emission pairs in the fluorescence spectra was proposed and tested. The results indicate that it is a promising technique, but still demanding further studies about the influence of broth composition in the spectra and how to take it into consideration in the chemometric modeling.