Pipeline Expansion Analysis
- 1. Thermal Expansion Analysis for Offshore Pipeline 105/07/19 THERMAL EXPANSION ANALYSIS FORTHERMAL EXPANSION ANALYSIS FOR OFFSHORE PIPELINEOFFSHORE PIPELINE BY NWAIWU, ZEPH PIPELINE DISCIPLINE
- 2. Thermal Expansion Analysis for Offshore Pipeline 205/07/19 Introduction Thermal expansion is the dimensionalThermal expansion is the dimensional incremental changes exhibited by solids,incremental changes exhibited by solids, liquids and gases in response to temperatureliquids and gases in response to temperature changeschanges
- 3. Thermal Expansion Analysis for Offshore Pipeline 305/07/19 Primarily, expansion can be calculated thus:Primarily, expansion can be calculated thus: ∆∆L=L= αα LL ∆∆TT WhereWhere ∆∆LL = Expansion (m, inch)= Expansion (m, inch) ∆∆TT = Change in temperature (= Change in temperature (°°C,C, °°F)F) αα = Coefficient of Linear Expansion (m/m= Coefficient of Linear Expansion (m/m °K, inch/inch °°K, inch/inch °F)F) LL = initial length of pipeline (m, inch)= initial length of pipeline (m, inch)
- 4. Thermal Expansion Analysis for Offshore Pipeline 405/07/19 Background: Pipeline Expansion Longitudinal expansion in pipeline is caused by temperature and pressure differential between the ambient conditions of the surrounding seawater and prevailing condition of the pipeline during Hydrotest and operational phases Consider a straight submarine pipelineConsider a straight submarine pipeline connected to a platform riser.connected to a platform riser.
- 5. Thermal Expansion Analysis for Offshore Pipeline The riser passes through clamps on theThe riser passes through clamps on the platform, and then has a 90° bend. At aplatform, and then has a 90° bend. At a short distance from the platform, theshort distance from the platform, the pipeline reaches the bottom, and from therepipeline reaches the bottom, and from there on is continuously in contact with the soil.on is continuously in contact with the soil. Because the temperature and pressure areBecause the temperature and pressure are higher, the pipeline tend to expand. Thehigher, the pipeline tend to expand. The frictional resistance between the pipelinefrictional resistance between the pipeline and seabed is always counteracting theand seabed is always counteracting the pipeline expansion.pipeline expansion.
- 6. Thermal Expansion Analysis for Offshore Pipeline 605/07/19 Explanation to Pipeline Expansion Depending on the length of the pipeline, atDepending on the length of the pipeline, at some distance from the platform, a pointsome distance from the platform, a point termed anchor point may occur at which thetermed anchor point may occur at which the forces producing expansion are counteractedforces producing expansion are counteracted by the cumulative effects of the soil frictionalby the cumulative effects of the soil frictional force.force. Thus longitudinal expansion stresses are setThus longitudinal expansion stresses are set up.up.
- 7. Thermal Expansion Analysis for Offshore Pipeline 705/07/19 Explanation to Pipeline Expansion At the platform, however, the pipeline is onlyAt the platform, however, the pipeline is only slightly constrained (by the vertical legs of theslightly constrained (by the vertical legs of the riser, which is relatively flexible) and there itriser, which is relatively flexible) and there it can expand freely and move towards thecan expand freely and move towards the platform)platform) At the platform, these movements areAt the platform, these movements are important because they can overstress the riserimportant because they can overstress the riser and the elbow.and the elbow. It is important to quantifyIt is important to quantify pipeline expansion in order to access its effectpipeline expansion in order to access its effect on the riser during riser stress analysis.on the riser during riser stress analysis.
- 8. Thermal Expansion Analysis for Offshore Pipeline 805/07/19 Industry Codes and standards and MPN Global Practices The following MPN Global Practices and International Codes and Standards are used in Pipeline Expansion calculations: COMPANY/MPN Global Practices: GP 86-01-01- Offshore Pipeline Design. GP 86-01-01S- Offshore Pipeline Design – MPN Supplement International Codes and Standards: ASME B31.8- Gas Transmission and Distribution Piping Systems. BS 8010-3 – Pipelines on subsea: Design, construction and Installation DNV-OS-F101 - Submarine Pipeline Systems.
- 9. Thermal Expansion Analysis for Offshore Pipeline 905/07/19 Method of Analysis The analytical formulation given by Palmer and Ling (1981) is been used to estimate pipeline end expansion. The temperature and pressure are simulated along the pipeline using continuity and momentum equation, and the simulated inlet and outlet temperatures and pressures are used for the expansion analysis. The temperature profile is also evaluated using the logarithm decay formula proposed by palmer and Ling
- 10. Thermal Expansion Analysis for Offshore Pipeline The Palmer and Ling basic formulation is given as: θ(x) = θ1 exp(-x/λ) Where: θ(x) is the temperature difference between the pipeline and the water at a distance x from the platform. θ1 = Temperature difference at the platform λ = Decay length
- 11. Thermal Expansion Analysis for Offshore Pipeline 1105/07/19 Calculations Pipeline is assumed straight and lying unburied on the seabed. The following input data are used; • Pipeline properties • Corrosion and Concrete Coating properties • Minimum contents weights • Temperature Profile and Pressure Profile • Geotechnical Data
- 12. Thermal Expansion Analysis for Offshore Pipeline 1205/07/19 Typical Design Data – Line Pipe Parameters Units Ekpe-Asabo Pipeline Pipeline outside diameter inch 16.00 Wall thickness inch 0.438 Approximate length ft (m) 63,234.5 (19,273.9) Adopted length (including riser sections) 64,466.2 (19659.4) Concrete coating thickness inch 1.5 Minimum water depth ft (m) 140 (42.7) Maximum water depth ft(m) 161 (49.1)
- 13. Thermal Expansion Analysis for Offshore Pipeline 1305/07/19 Parameters Notation Value Units Material density 490 lb/ft3 Young modulus E 30 X 103 psi Poisson ratio ν 0.3 Specified minimum yield strength SMYS 65000 psi Steel thermal conductivity 1.16 X 10-5 °F Design temperature 150 °F Operating temperature 105 °F Hydrotest temperature 75 °F Corrosion coating thickness tcc 0.027 In Concrete coating thickness tcon 1.5 in Density of liquid ρf 53.745 lb/ft3 Density of steel ρs 490 lb/ft3 Density of water ρw 64 lb/ft3 Density of corrosion coating ρcc 90 lb/ft3 Density of concrete coating ρcon 190 lb/ft3 Typical Design Data Continued
- 14. Thermal Expansion Analysis for Offshore Pipeline 1405/07/19 SOLUTION TO THERMAL EXPANSION If the pipeline expansion is of limited magnitude, an effective and cost effective design is obtained by letting the expansion be taken by elastic deformation of the riser. Where pipeline expansion is excessive expansion loop will be required to absorb some of the expansion, thereby protecting the riser, its supports and associate jacket members from overstressing.
- 15. Thermal Expansion Analysis for Offshore Pipeline EXPANSION SPOOL DRAWING 1505/07/19
- 16. Thermal Expansion Analysis for Offshore Pipeline EXPANSION SPOOL 1605/07/19
- 17. Thermal Expansion Analysis for Offshore Pipeline 1705/07/19 EXAMPLE OF PLATFORM APPROACH
- 18. Thermal Expansion Analysis for Offshore Pipeline 1805/07/19 Any Questions
- 19. Thermal Expansion Analysis for Offshore Pipeline 1905/07/19