Pipeline design (Dense flow versus two-phase flow)

Supervisor:�Dr.Rola Afifi�

BY:

Youssef Ezzat

Abdelrahman Yehia

Youssef Ahmed

Muhammed Ahmed

Karim Yasser

INTRODUCTION

Pipeline design and construction basics�

The major factors influencing the pipeline design and construction

TYPES OF PIPELINES.

Pipeline Routing affecting Factors:

Two phase types

Two-phase flow types:

• Gas-Liquid flow
• Solid-Liquid flow
• Liquid-Liquid flow
• Gas-Solid flow

Flow regimes:

• Flow rate
• Phase type
• Pipe displacement (Vertical, horizontal & inclined)

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Gas-Liquid flow�

Horizontal pipelines

• Bubbly flow
• Stratified flow
• Slug and Plug flow
• Annular flow

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Solid-Liquid Flows�

• Newtonian flow regimes

• Non-Newtonian flow regimes

Liquid-Liquid flow

• Separated flow
• Phase inversion flow
• Dispersed flow

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Gas-Solid flow �

Slug flow

Packed bed

Dune flow

Homogenous flow

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PARAMETERS OF TWO-PHASE FLOW

TWO-PHASE FLOWS MODELLING APPROACHES�

• Homogenous model.
• Separated flow model.
• Multi-fluid model.
• Drift flux model.
• Computational fluid dynamic (CFD) model.

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Description of the Dense phase�

• Dense phase is a fourth phase.

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• High Temperature , High Pressure.

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• Similarity to gases and liquids.

Thermodynamic behavior

Hydraulic benefits

• its high density avoid liquid formation over long distances.
• Greater transport capacity
• Transportation of natural gas liquids
• Implementation of a single pipeline

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Dense Phase Conveying�

Dense phase transfer generally occurs in one of two basic forms:

• plug flow
• moving bed (dune) flow.

Difference between dense phase types�

Applications of two-phase flow

Applications of two-phase flow

METHODS USED FOR TWO-PHASE FLOW CALCULATIONS

METHODS USED FOR TWO-PHASE FLOW CALCULATIONS

Dense flow applications

HIGH-PRESSURE DELIVERY CAPABILITY

Many chemical reactors and fluidized bed combustor systems operate at high pressure and require materials to be fed into a high-pressure operating system.

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MULTIPLE-DISTANCE CONVEYING

• convey a material over a range of distances
• supplying a number of widely spaced reception points.
• differing air requirements and material flow rates.

ProMax

Introduction to ProMax

• powerful and versatile stream-based process simulation package.
• design and optimize gas processing, refining, and chemical facilities.
• contains over 50 thermodynamic package combinations.

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Used Components

Equations

Equations

Equations

Cases

Two phase case

Dense phase case

Liquid holdup and Viscosity results

Pressure and Velocity results

LOW PRESSURE VERSUS HIGH PRESSURE DENSE PHASE NATURAL GAS PIPELINE TRANSPORTATION

Case A (Dense phase)

Case B (Intermediate Pressure)

Case C (low pressure)

compressor stations power

pipeline inlet pressure for the three cases

Pressure in the pipeline

Temperature in the pipeline

Gas density in the pipeline

Gas velocity in the pipeline

Gas viscosity in the pipeline

ECONOMIC ANALYSIS

The capital costs (CAPEX)

1. Pipeline cost
2. Pipeline coatings
3. Labor and installation cost
4. Compressor stations cost
5. Compressor stations installation
6. Mainline valve station

7. Meter stations

8. Telecommunication systems

9. Environmental and permitting

10. Right of way (ROW)

11. Engineering and construction management

12.Contingency and other costs

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Pipeline cost

Pipeline coatings, labor and installation cost

• 15% of the pipeline cost adder for coatings.

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• Pipeline total installed cost is 2.5 times the pipe steel plus coatings cost.

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• This factor has been surprisingly consistent historically for both onshore and offshore long distance and larger diameter pipelines.

Mainline valve stations and Meter stations

• Department of Transportation code requirements may dictate that a mainline valve be installed every 20 miles
• Meter stations may also be estimated as a fixed price including material and labor for a particular site. four such meter stations for every 100-mile gas pipeline.

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Right of way (ROW)

• ROW for a pipeline is acquired from private parties, state and local governments, and federal agencies for a fee.
• For most gas pipelines, the initial ROW costs will be in the range of 6% to 10% of total project costs

Engineering and construction, and Contingency and other costs

• On a typical pipeline project, engineering, and construction management costs ranges from 15% to 20% of total pipeline project costs.
• Contingency costs may range between 15% and 20% of the total project costs.

The operating costs (OPEX)

1. Compressor station electrical energy cost.
2. Compressor station maintenance.
3. Fuel consumption.
4. Compressor station maintenance cost.
5. Rental and recurring ROW costs.
6. Administrative and payroll costs.
7. Other operating and management costs

Compressor station electrical energy cost

CASE A, B AND C ECONOMICAL COMPARISON

To simplify some calculations, we will put some assumptions that will be constant in all three cases:

• Lifetime = 20 years
• Salvage value = 0
• Tax rate = 40%
• The capital will be financed with 70% debt at 8% interest. The rate of return allowed on the 30% equity is 12%.
• Straight line depreciation method.

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Equity cost and loan amortization cost

Pipeline tariffs

Net present value

Net present value for case A, B, and C

NORD 2 STREAM – TWO-PHASE VERSUS DENSE PHASE NATURAL GAS TRANSPORTATION

Two phase case�

Dense phase cycles�

Compressors Differences Table�

Two Phase Pipeline Specifications Table �

Dense Phase cycle 1 Pipeline specifications Table �

Dense Phase cycle 2 Pipeline specifications Table �

Temperature results�

Pressure results�

Liquid hold up results�

Liquid hold up results�

Gas Velocity results�

Gas Viscosity results�

NORD 2 STREAM – Economical analysis

Gas Viscosity results�

the annual operating cost of Two-phase, Dense-1, and Dense-2

Net present value calculations�

CONCLUSION

RECOMMENDATION

Wall thickness

• P = max allowable stress operating pressure = 1.1 × 3300 = 3630 psi
• Outer diameter = 43 inch
• Joint efficiency = 1 (assumed)
• f₁ is wall thickness tolerance =1 (assumed)
• f₂ is design factor, 0.4 to 0.72  (here set  to be 0.7 for remote area)
• σ is the pipe material yield stress (material grade X65 to be 65,000 psi)
• CA is the corrosion allowance (assumed to be 0 mm, for dry gas)

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