A exploração e a produção não convencionais de petróleo e gás natural:uma proposta de regulação não convencional

Esta dissertação debruçou-se sobre o estudo da regulação da exploração e da produção de recursos não convencionais de petróleo e gás natural e de controvérsias acerca da matéria. Partimos de fundamentos e segmentos do Direito Internacional Contemporâneo, sua interseção com o direito interno, precisamente no que diz respeito ao tema da regulação e os seus novos contornos, para então adentrar na regulação propriamente dita dos recursos não convencionais. Após ilustrarmos os diferentes tratamentos conferidos à exploração e à produção de recursos não convencionais no direito comparado, destacamos, como estudo de caso, o tratamento conferido no Brasil à questão e as controvérsias decorrentes dos não convencionais. Ao final, apresentamos algumas proposições com vistas a viabilizar tal atividade não apenas no Brasil como em demais países, por meio de uma regulação não convencional, isto é, elaborada de forma compartilhada e global, pautada nas Melhores Práticas da Indústria, nos princípios de direito internacional e na governança global, que respeite as peculiaridades dos recursos não convencionais e que conte com uma maior aceitação pelos diferentes atores envolvidos e/ou afetados por essa atividade exploratória, por meio da promoção do diálogo e do esclarecimento necessário. Acreditamos que dessa forma estar-se-ia por estimular uma era de ouro global ao gás natural, a considerar todas as suas vantagens perante demais fontes energéticas, proporcionando o desenvolvimento dos Estados de forma ambientalmente sustentável, resguardando-se os interesses dos investidores e, principalmente, dos principais beneficiários da política energética que são os indivíduos.

Spray combustion characteristics of palm biodiesel

The potential of palm methyl esters (PME) as an alternative fuel for gas turbines is investigated using a swirl burner. The main air flow is preheated to 623 K, and a swirling spray flame is established at atmospheric pressure. The spray combustion characteristics of PME are compared to diesel and Jet-A1 fuel under the same burner power output of 6 kW. Investigation of the fuel atomizing characteristics using phase Doppler anemometry (PDA) shows that most droplets are distributed within the flame reaction zone region. PME droplets exhibit higher Sautermean diameter (SMD) values than baseline fuels, and thus higher droplet penetration length and longer evaporation timescales. The PME swirl flame presents a different visible flame reaction zone while combusting with low luminosity and produces no soot. NO x emissions per unit mass of fuel and per unit energy are reduced by using PME relative to those of conventional fuels. © 2012 Copyright Taylor and Francis Group, LLC.

Autoignition of monodisperse biodiesel and diesel sprays in turbulent flows

A new experimental configuration has been developed to examine the effects of flow on the autoignition of dilute diesel and biodiesel sprays, where the spray is injected in the form of monodisperse individual droplets at right angles to a hot air turbulent flow. The ignition location has been measured by monitoring the OH * chemiluminescence. A qualitative comparison of the flame behaviour between ethanol, acetone, heptane and biodiesel as fuels has also been carried out. With decreasing volatility of the fuel, the flame showed progressively a higher number of individual droplets burning, with the first autoignition spots appearing at random locations but in general earlier than the intense droplet-flame emission. The time-averaged autoignition length increased with increasing air velocity and with increasing intensity of the turbulence, while it decreased with the temperature and the droplet size. The data can be used for validating models for two-phase turbulent combustion. © 2012 Elsevier Inc.

Effects of the biodiesel fuel physical properties on the swirl stabilised spray combustion characteristics

An increasin g interest in biofuel applications in modern engines requires a better understanding of biodiesel combustion behaviour. Many numerical studies have been carried out on unsteady combustion of biodiesel in situations similar to diesel engines, but very few studies have been done on the steady combustion of biodiesel in situations similar to a gas turbine combustor environment. The study of biodiesel spray combustion in gas turbine applications is of special interest due to the possible use of biodiesel in the power generation and aviation industries. In modelling spray combustion, an accurate representation of the physical properties of the fuel is a first important step, since spray formation is largely influenced by fuel properties such as viscosity, density, surface tension and vapour pressure. In the present work, a calculated biodiesel properties database based on the measured composition of Fatty Acid Methyl Esters (FAME) has been implemented in a multi-dimensional Computational Fluid Dynamics (CFD) spray simulation code. Simulations of non-reacting and reacting atmospheric-pressure sprays of both diesel and biodiesel have been carried out using a spray burner configuration for which experimental data is available. A pre-defined droplet size probability density function (pdf) has been implemented together with droplet dynamics based on phase Doppler anemometry (PDA) measurements in the near-nozzle region. The gas phase boundary condition for the reacting spray cases is similar to that of the experiment which employs a plain air-blast atomiser and a straight-vane axial swirler for flame stabilisation. A reaction mechanism for heptane has been used to represent the chemistry for both diesel and biodiesel. Simulated flame heights, spray characteristics and gas phase velocities have been found to compare well with the experimental results. In the reacting spray cases, biodiesel shows a smaller mean droplet size compared to that of diesel at a constant fuel mass flow rate. A lack of sensitivity towards different fuel properties has been observed based on the non-reacting spray simulations, which indicates a need for improved models of secondary breakup. By comparing the results of the non-reacting and reacting spray simulations, an improvement in the complexity of the physical modelling is achieved which is necessary in the understanding of the complex physical processes involved in spray combustion simulation. Copyright © 2012 SAE International.

Spray flame structure of rapeseed biodiesel and Jet-A1 fuel

The spray combustion characteristics of rapeseed methyl esters (RME) were compared to Jet-A1 fuel using a gas turbine type combustor. The swirling spray flames for both fuels were established at a constant power output of 6 kW. The main swirling air flow was preheated to 350 C prior to coaxially enveloping the airblast-atomized liquid fuel spray at atmospheric pressure. Investigation of the fundamental spray combustion was performed via measurements of the fuel droplet sizes and velocities, gas phase flow fields and flame reaction zones. The spray flame droplets and flow fields in the combustors were characterised using phase Doppler anemometry (PDA) and particle imaging velocimetry (PIV) respectively. Flame chemiluminescence imaging was employed to identify the flame reaction zones. The highest droplet concentration zone extends along a 30 angle from the symmetry axis, inside the flame zone. Only small droplets(<17 μ) (<17 μm)are found around the centreline region, while larger droplets are found at the edge of the spray outside the flame reaction zone. RME exhibits spray characteristics similar to Jet-A1 but with droplet concentration and volume fluxes four times higher, consistent with the expected longer droplet evaporation timescale. The flow field characteristics for both RME and Jet-A1 spray flames are very similar despite the significantly different visible characteristics of the flame reaction zones. © 2013 Elsevier Ltd. All rights reserved.

Discrete multicomponent model for biodiesel spray combustion simulation

An important first step in spray combustion simulation is an accurate determination of the fuel properties which affects the modelling of spray formation and reaction. In a practical combustion simulation, the implementation of a multicomponent model is important in capturing the relative volatility of different fuel components. A Discrete Multicomponent (DM) model is deemed to be an appropriate candidate to model a composite fuel like biodiesel which consists of four components of fatty acid methyl esters (FAME). In this paper, the DM model is compared with the traditional Continuous Thermodynamics (CTM) model for both diesel and biodiesel. The CTM model is formulated based on mixing rules that incorporate the physical and thermophysical properties of pure components into a single continuous surrogate for the composite fuel. The models are implemented within the open-source CFD code OpenFOAM, and a semi-quantitative comparison is made between the predicted spray-combustion characteristics and optical measurements of a swirl-stabilised flame of diesel and biodiesel. The DM model performs better than the CTM model in predicting a higher magnitude of heat release rate in the top flame brush region of the biodiesel flame compared to that of the diesel flame. Using both the DM and CTM models, the simulation successfully reproduces the droplet size, volume flux, and droplet density profiles of diesel and biodiesel. The DM model predicts a longer spray penetration length for biodiesel compared to that of diesel, as seen in the experimental data. Also, the DM model reproduces a segregated biodiesel fuel vapour field and spray in which the most abundant FAME component has the longest vapour penetration. In the biodiesel flame, the relative abundance of each fuel component is found to dominate over the relative volatility in terms of the vapour species distribution and vice versa in the liquid species distribution. © 2014 Elsevier Ltd. All rights reserved.

Synthesis of biodiesel from waste cooking oil using immobilized lipase in fixed bed reactor

Waste cooking oil (WCO) is the residue from the kitchen, restaurants, food factories and even human and animal waste which not only harm people's health but also causes environmental pollution. The production of biodiesel from waste cooking oil to partially substitute petroleum diesel is one of the measures for solving the twin problems of environment pollution and energy shortage. In this project, synthesis of biodiesel was catalyzed by immobilized Candida lipase in a three-step fixed bed reactor. The reaction solution was a mixture of WCO, water, methanol and solvent (hexane). The main product was biodiesel consisted of fatty acid methyl ester (FAME), of which methyl oleate was the main component. Effects of lipase, solvent, water, and temperature and flow of the reaction mixture on the synthesis of biodiesel were analyzed. The results indicate that a 91.08% of FAME can be achieved in the end product under optimal conditions. Most of the chemical and physical characters of the biodiesel were superior to the standards for 0(#)diesel (GB/T 19147) and biodiesel (DIN V51606 and ASTM D-6751).

Lipase-catalyzed synthesis of biodiesel from acid oil in fixed bed reactor

Acid oil, which is a by-product in vegetable oil refining, mainly contains free fatty acids (FFAs) and acylglycerols and is a feedstock for production of biodiesel fuel now. The transesterification of acid oil and methanol to biodiesel was catalyzed by immobilized Candida lipase in fixed bed reactors. The reactant solution was a mixture of acid oil, water, methanol and solvent (hexane) and the main product was biodiesel composed of fatty acid methyl ester (FAME) of which the main component was methyl oleate. The effects of lipase content, solvent content, water content temperature and flow velocity of the reactant on the reaction were analyzed. The experimental results indicate that a maximum FAME content of 90.18% can be obtained in the end product under optimum conditions. Most of the chemical and physical properties of the biodiesel were superior to the standards for 0(#) diesel (GB/T 19147) and biodiesel (DIN V51606 and ASTM D6751).