NUMERIC SIMULATION OF A PIG MOVE INSIDE SERVICE PIPES

Transcription

1 NUMERIC SIMULATION OF A PIG MOVE INSIDE SERVICE PIPES Dr.-Ing. Max Suell Dutra M.Sc. (e. c.) John Faber Archila Diaz Robotics Laboratory COPPE/UFRJ

2 Index LabRob Presentation Problem Description Methodology Mathematical Models Simulations Conclusion References

3 Robotics Laboratory UFRJ The Robotics Laboratory (LabRob) is part of the postgraduate program in mechanical engineering of Institute Alberto Luiz Coimbra of postgraduate and investigation of engineering, COPPE/UFRJ, is linked to the sector of the machine design and is specialized in development of products in the area of mechatronics.

4 Robotics Laboratory The LabRob works with kinematical and dynamical analyses, virtual prototypes, technical feasibility studies, design, construction and testing of mechanical systems.

5 Problem Description The pipelines correspond to the veins and arteries of our cities and industries. Its use is universal and has records of first pipes to 4000 B C. Distribution of pipes in the world (Bueno, 2007)

6 Problem Description In the U.S. it is estimated that km of pipelines to be rehabilitated in the next 9 years. In other countries like Russia approximately 20% of oil and gas pipelines are near the end of life. In 15 years 50% of all pipelines in the world come to the end of its operation. In Brazil it is estimated that there are more than km of pipelines buried.

7 Problem Description The maintenance of pipelines is a part of the program of integrity assurance, which are based on data from inspections of service lines. In case of buried pipelines one of the main tools of inspection is the PIG (Pipeline Inspection Gauge) which is used for inspection, maintenance, and is a procedure standard for gas and oil. Integrity evaluation process of the threat of external corrosion (Thomas et al., 2000)

8 Problem Description The PIGs have several purposes during the travel into the pipeline, like: cleaning the pipe, removal of liquid, separation of products and inspection, among others. An operation with PIG demand the evaluation of various operational parameters such as maximum and minimum pressures and speed of movement of the pig during the planning stage and keept certain limits during the monitoring of the operation.

9 Methodology Methodology (ARCHILA et. al., 2008)

10 Methodology CFD Methodology used in this work Mathematical Modeling Kinematics Fluid PIG Dynamics Fluid PIG Solve equations system

11 Mathematical Modeling Kinematics. OCENSA MEDGAZ OSPAR

12 Mathematical Modeling Kinematics φ ( φ ) ( φ ) ( φ ) ( φ ) x ' c sin / 2 c sin / 2 ω i r = y = c cos / 2 c cos / 2 ω d φ c / b c / b t c 0 x x0 t c cos y y φ 0 ( ω d ω i = + + ) dt 0 2 φ φ 0 t 0 sin 2 c b φ ( ω d + ω i ) dt dt ( ω d ω i )

13 Mathematical Modeling Dynamics Continuity equation t x ( ρ Adx) + ( ρ AV ) dx = 0 Fluid compressibility (Isothermal) Change of pipe area 1 dρ 1 = ρ ρ 2 dt a dt 1 da 1 A dp V A = + A dt A P dt A s dp PA A P dx x τ 0π Ddx θ PA + ( A) dx x ρ P P V V A t x x A x V + ρc + ρc = = ξ = 1+ ( 1 ν ) 2 c a 2 / ξ ρa D t ' E

14 Mathematical Modeling Dynamics Friction 64 f = Re f Viscosity τ 0 = DV Fs = ρ A dx Dt f 8 ρ V V ε 5,74 f = 0, 25 log D + 3,7 Re 0,9 = , ,14 10 Re 2 ( ) µ = µ 0 exp cµ, P P P0 PA dx A P dx x τ 0π Ddx θ PA + ( A) dx x ρ X V V 1 P f V V + V = g sinθ t x ρ x 2 D

15 Mathematical Modeling Dynamics F x d L L = dt x& x L = mv mgh x ( ) F = P P A F 1 2 a θ 2 d x = 2 ( 1 2 ) sinθ a m P P A mg F dt

16 Simulations Results

17 Simulations Results

18 Simulations Results

19 Simulations Results

20 Simulations Results

21 Simulations Results

22 Conclusion The solution of the mathematical modeling of coupled nonlinear differential equations using the finite differences in a rectangular grid, with coordinates of time and position, was presented. An algorithm to simulate movement of PIGs in service lines, modelled using Matlab environment, obtaining solutions for different configurations of the pipelines under some conditions of operation was developed and presented.

23 Conclusion The results of the simulations show that the pressure can achieve 1.3 times the operation pressure. This fact shows the importance of the effect analysis during the passage of PIGs in service lines. The maximum allowed pressure of operation (PMOA) can be oversteped. The minimum conditions of pressure generating conditions for slack line flow, damaging the pipe or decreasing its life can be achieved and must be avoided.

24 References ARCHILA, J. F. D., DUTRA, M. S., 2008, Numeric Simulation of a PIG move inside service pipes. In: 3rd Latin American CFD Meeting Applied to Oil & Gas Industry, Rio de Janeiro, Brasil. ARCHILA, J. F. D., DUTRA, M. S., 2008, Pipelines Inspection Robots. In: Rio Oil & Gas Expo and Conference, Rio de Janeiro, Brasil. ARCHILA, J. F. D., STUECK, A., DUTRA, M. S., 2008, Robôs para inspeção de linhas de serviço. In: V National Congress of Mechanical Engineering, Salvador, Bahia, Brasil.

25 References AZEVEDO, L. F., BRAGA, A. M., NIECKELE, A. O., 1997, Relatório final Projeto e Simulação de Deslocamento de PIGs, Departamento de Engenharia Mecânica Pontifícia Universidade Católica do Rio PUC- Rio, Rio de Janeiro, Brasil. BUENO, A. H. S., 2007, Avaliação Integrada de Mecanismos de Falha por Corrosão em Dutos, Tese de Doutorado, COPPE/UFRJ, Rio de Janeiro, Brasil.