Severino Rodrigues de Farias Neto

Numerical Study of Heavy Oil Flow on Horizontal Pipe Lubricated by Water

This chapter reports information related to multiphase flow with emphasis to core-annular flow. Industrial application has been given to transient water-heavy ultraviscous oil two-phase flow in horizontal pipe. The high viscosity heavy oil transportation is one of the main technological challenges for the oil industry. This fact is related with the high pressure drop due to the viscous effects during the flow. Different techniques for the heavy oil transportation have been cited in the literature, core-flow is one. In this technique, water is injected in the pipe and flows as an annular film near the wall while oil moves in the core region. This way, a smallest amount of energy is required for heavy oil pumping. Mathematical formulation to describe transient and isothermal two-phase flow (water-heavy oil) is presented. Results of the velocity, pressure and volume fraction distributions of the phases were obtained and analyzed. A large reduction of pressure drop by comparison with single phase heavy oil flow (around 59 times) was verified and shows the efficiency of the technique applied to production and transportation of heavy oils.

Isothermal and non-isothermal water and oil two-phase flow (core-flow) in curved pipes

The occurrence of heavy oils in the world has increased substantially and points favorable to investment in exploration of mineral deposits and consequently, for the development of new technologies. Heavy oil has a high viscosity that varies from 100 to 10,000 times greater than the viscosity of water. The high pressure due to friction and viscous effects during the transport of heavy oil has been a major challenge, for itself to be economically viable for production or transportation. The core annular flow technique is a more recent technology favorable the explotation and transportation of heavy oils that provides a considerable reduction of pressure drop during the flow of these oils type. In this sense, this paper presents a 3D numerical study involving the heavy oil transportation in curved pipes, using the core-flow technique by CFD (ANSYS CFX® 12.0). Results of pressure, velocity, volume fraction and temperature distribution of the heavy oil are presented and analysed.

Theoretical/Experimental Study of an Upflow Anaerobic Sludge Blanket Reactor Treating Domestic Wastewater

This work reports a theoretical and experimental study to evaluate the fluid dynamic of an Upflow Anaerobic Sludge Blanket reactor (UASB), treating domestic wastewater in a pilot scale. Simulations were developed using the Ansys CFX 10.0. For validating the numerical results, an experimental study was conducted by monitoring the total concentration of suspended solids in the effluent and pressure along the reactor. The comparative analysis between the numerical and experimental results of the pressure and sludge concentration in the outlet of the reactor presented few differences, being considered satisfactory.

Heat and Mass Transfer and Volume Variations during Drying of Industrial Ceramic Bricks: An Experimental Investigation

The purpose of this paper is to present an experimental study of brick drying. For the drying experiments, industrial brick (clay) was dried in an oven under controlled conditions of air velocity, air temperature and air relative humidity. The continuous drying experiments ended when the mass reached constant weight. In order, to obtain the balanced moisture content, each sample was kept under the same drying air temperature for 48 hours inside the oven. The tests were performed under atmospheric pressure. Results of the drying and heating kinetics and volume variations during the process are shown and analyzed. It was verified that air temperature has big influence in the drying rate during process. It was verified that the largest temperature, moisture content and stress gradients are located in the vertexes of the brick. The drying process happens in the falling drying rate period.

Applying CFD in the analysis of heavy oil - water two-phase flow in joints by using core annular flow technique

In the oil industry the multiphase flow occur throughout the production chain, from reservoir rock until separation units through the production column, risers and pipelines. During the whole process the fluid flows through the horizontal pipes, curves, connections and T joints. Today, technological and economic challenges facing the oil industry is related to heavy oil transportation due to its unfavourable characteristics such as high viscosity and high density that provokes high pressure drop along the flow. The coreflow technique consists in the injection of small amounts of water into the pipe to form a ring of water between the oil and the wall of the pipe which provides the reduction of friction pressure drop along the flow. This paper aim to model and simulate the transient two-phase flow (water-heavy oil) in a horizontal pipe and T joint by numerical simulation using the software ANSYS CFX® Release 12.0. Results of pressure and volumetric fraction distribution inside the horizontal pipe and T joi...

Drying of Ceramic Hollow Bricks in an Industrial Tunnel Dryer: A Finite Volume Analysis

This paper aims to study the drying of industrial hollow bricks in a tunnel dryer cross flow type. The theoretical model is based on mass and energy conservation equations applied to air and product. To validate the methodology, numerical and experimental results for the moisture content and the temperature of brick during the drying in an industrial scale are compared and a good correlation was obtained. Results of moisture content and temperature of the product, and temperature, relative humidity and absolute humidity of drying air as a function of drying time and position in the dryer are presented and analyzed.

Evaluation of Multiphase Flow in the Presence of Leak in Oil Pipelines: Modeling and Simulation

The transport of oil and its derivates is mainly done through pipelines linking the oil fields, refineries and distribution networks to consumers. They are considered the best, safe and economical way to fluids transportation over long distances. Despite significant advances in the development of lighter and stronger materials for the construction of pipelines and the growing number of gas and oil pipelines, many problems of leaks have been observed, which has encouraged the development of reliable techniques to inspect and detect quickly and accurately possible leaks along these pipelines. The goal is to eliminate or minimize damage to the oil industry and mainly to the environment. In this context, this paper aims to study the thermo-fluid dynamics of a transient three-phase flow (oil, water and gas) in a horizontal pipe in the presence of a leakage at different positions. Herein it was applied a 3D Eulerian-Eulerian model, including the transient turbulent model (RNG k-ε), using the ANSYS CFX® 12.1 commercial package to perform all simulations. Numerical results of velocity, pressure and volume fraction fields of the involved phases are presented and discussed.

Hydrodynamics of Oil-Water with Leakage by CFD

The oil industry has sought to minimize the environmental impact from mining activities and oil transportation. The oil transportation by pipeline is subject to failures and leaks that cause financial losses and environmental damage, often irreparable. In this sense, the aim of this study is to evaluate the influence of the leak diameter in the behavior of the two-phase flow (oil and water) in a pipe. A transient and incompressible multiphase flow mathematical model based on the particle model was used here. Oil is the dispersed phase while water is the continuous phase. To model the turbulence effect it was used the standard k-ε model. All simulations were carried out using the Ansys CFX® commercial code. Results of the pressure, velocity and volumetric fraction of the phases are presented and discussed. The results confirm the difficulty to detect leakage with small diameters.

Multiphase Flow and Heat Transfer in Risers

Multiphase flows commonly occur in the production and transportation of oil, natural gas and water. In this type of flow, the phases can flow in different spatial configurations disposed inside the pipe, so called multiphase flow patterns. The identification of flow patterns and the determination of the pressure drop along the pipe lines for different volumetric flows are important parameters for management and control of production. In this sense, this work proposes to numerically investigate the non-isothermal multiphase flow of a stream of ultraviscous heavy oils containing water and natural gas in submerged risers (catenary) via numerical simulation (ANSYS CFX 11.0). Results of the pressure, volumetric fractions and temperature distributions are presented and analyzed. Numerical results show that the heat transfer was more pronounced when using the largest volume fraction of gas phases.

Hydrodynamic Study of Oil Leakage in Pipeline via CFD

This paper describes the transient dynamics behavior of oil flow in a pipe with the presence of one or two leaks through fluid dynamics simulations using the Ansys CFX commercial software. The pipe...This paper describes the transient dynamics behavior of oil flow in a pipe with the presence of one or two leaks through fluid dynamics simulations using the Ansys CFX commercial software. The pipe section is three-dimensional with a pipe length of 10 m, a pipe diameter of 20 cm, and leak diameter of 1.6 mm. The interest of this work is to evaluate the influence of the flow velocity, and the number and position of leaks on the transient pressure behavior. These new data may provide support for more efficient detection systems. Thus, this work intends to contribute to the development of tools of operations in oil and gas industry.