Estudo energético da configuração em série de colunas de destilação por filme descendente

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Química, Florianópolis, 2017.Processos de destilação são largamente empregados na indústria de petróleo e petroquímica. Unidades intensificadas energeticamente tem sido propostas, visando a minimização dos requerimentos energéticos que intrinsicamente são altos neste tipo de processo. Colunas de múltiplo efeito, cuja separação é realizada em uma série de unidades, são um exemplo da possibilidade de otimizar a energia necessária para a separação. Neste sentido, este trabalho teve como objetivo avaliar a eficiência energética de uma configuração em série de destilação por filme descendente com aquecimento por termossifão na separação de uma mistura etanol-água. Experimentos foram realizados com três unidades em série, obtendo-se fração mássica de etanol na terceira coluna igual a 82,7%. Este resultado demonstra a possibilidade da utilização de uma série de colunas de filme descendente para incrementar a fração do componente mais volátil. Em paralelo, um modelo matemático para simulação desta unidade foi proposto, a partir do qual foram calculados os requerimentos energéticos da configuração proposta. Este modelo foi desenvolvido utilizando o software Wolfram Mathematica®. O modelo e as simulações correspondentes permitiram avaliar os perfis de temperatura ao longo do comprimento da unidade, cujos valores não podem ser determinados experimentalmente. Em relação a análise energética, observou-se que unidade de filme descendente é mais vantajosa do ponto de vista energético, representando economia de cerca de 29,5% quando comparada com a separação em uma unidade convencional.Abstract : Distillation processes are widely used in petroleum and petrochemical industry. Energetically intensified units have been proposed aiming at minimizing the energy requirements that are intrinsically high in this type of process. Multi-effect columns, whose separation is performed by a series unit, are an example of the possibility of optimizing energy needed for the separation. For this sense, this work had as objective to evaluate the energy efficiency of a series configuration of falling film distillation columns with thermosyphon heating in the separation of an ethanol-water mixture. Experiments were performed with a three units series, obtaining a mass fraction of ethanol in the third column equal to 82,7 %. The result demonstrated the possibility of using a series of falling film distillation columns to increase the concentration of more volatile component. In addition, a mathematical model of this unit was proposed and simulated, where the energy requirements of the proposed configuration were calculated. This model was developed using Wolfram Mathematica® software. The model and its simulations allowed to evaluate the temperature profiles along the unit length, whose values cannot be determined experimentally. With regard to energy analysis, it has been observed that falling film distillation unit was more energy-efficient conventional unit, representing savings of about 29,5 % as compared to separation in a conventional unit

A search for ultra-high-energy photons at the Pierre Auger Observatory exploiting air-shower universality

The Pierre Auger Observatory is the most sensitive detector to primary photons with energies above ∼0.2 EeV. It measures extensive air showers using a hybrid technique that combines a fluorescence detector (FD) with a ground array of particle detectors (SD). The signatures of a photon-induced air shower are a larger atmospheric depth at the shower maximum (X$_{max}$) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced background. Using observables measured by the FD and SD, three photon searches in different energy bands are performed. In particular, between threshold energies of 1-10 EeV, a new analysis technique has been developed by combining the FD-based measurement of X$_{max}$ with the SD signal through a parameter related to its muon content, derived from the universality of the air showers. This technique has led to a better photon/hadron separation and, consequently, to a higher search sensitivity, resulting in a tighter upper limit than before. The outcome of this new analysis is presented here, along with previous results in the energy ranges below 1 EeV and above 10 EeV. From the data collected by the Pierre Auger Observatory in about 15 years of operation, the most stringent constraints on the fraction of photons in the cosmic flux are set over almost three decades in energy

Study on multi-ELVES in the Pierre Auger Observatory

Since 2013, the four sites of the Fluorescence Detector (FD) of the Pierre Auger Observatory record ELVES with a dedicated trigger. These UV light emissions are correlated to distant lightning strikes. The length of recorded traces has been increased from 100 μs (2013), to 300 μs (2014-16), to 900 μs (2017-present), to progressively extend the observation of the light emission towards the vertical of the causative lightning and beyond. A large fraction of the observed events shows double ELVES within the time window, and, in some cases, even more complex structures are observed. The nature of the multi-ELVES is not completely understood but may be related to the different types of lightning in which they are originated. For example, it is known that Narrow Bipolar Events can produce double ELVES, and Energetic In-cloud Pulses, occurring between the main negative and upper positive charge layer of clouds, can induce double and even quadruple ELVES in the ionosphere. This report shows the seasonal and daily dependence of the time gap, amplitude ratio, and correlation between the pulse widths of the peaks in a sample of 1000+ multi-ELVES events recorded during the period 2014-20. The events have been compared with data from other satellite and ground-based sensing devices to study the correlation of their properties with lightning observables such as altitude and polarity

Extraction of the Muon Signals Recorded with the Surface Detector of the Pierre Auger Observatory Using Recurrent Neural Networks

We present a method based on the use of Recurrent Neural Networks to extract the muon component from the time traces registered with water-Cherenkov detector (WCD) stations of the Surface Detector of the Pierre Auger Observatory. The design of the WCDs does not allow to separate the contribution of muons to the time traces obtained from the WCDs from those of photons, electrons and positrons for all events. Separating the muon and electromagnetic components is crucial for the determination of the nature of the primary cosmic rays and properties of the hadronic interactions at ultra-high energies. We trained a neural network to extract the muon and the electromagnetic components from the WCD traces using a large set of simulated air showers, with around 450 000 simulated events. For training and evaluating the performance of the neural network, simulated events with energies between 1018.5, eV and 1020 eV and zenith angles below 60 degrees were used. We also study the performance of this method on experimental data of the Pierre Auger Observatory and show that our predicted muon lateral distributions agree with the parameterizations obtained by the AGASA collaboration