1 Pipeline Overview

2010 Yoon Consulting 1

Pipeline System Design:Introduction

Mike Yoon, Ph.D.


Understand the basics of liquid pipeline hydraulics, pumping requirements, and pipeline system design and operation.

Understand the petroleum liquid properties required for pipeline system design and operation.

Objectives


Cover single phase petroleum liquids, Refined petroleum products, High vapour pressure (HVP) liquids, Crude oil including heavy viscous fluid.

Include high pressure transmission pipeline with pump stations.

Exclude multi-phase flow lines. This is a pipeline system design course, covering

hydraulic and operational aspects but excluding mechanical and economic aspects of design.

Scope


Introduction Pipeline history

Petroleum and pipeline industries Reasons of using pipelines

Types of pipelines

Challenges

Types of pipeline ownership

Definitions Pipeline components

Key Topics


Fluid flow - Bernoulli, Reynolds, Stokes Heat - Fourier, Carnot Heat and Work - Boyle, Joule, Watt Mechanics and Materials - Newton, Hooke,

Bessemer

History of Pipeline Physics


Developments of the Pipeline Industry

1802: First commercial use: New York 1891: First high-pressure, long distance pipeline 1943: War effort drives continental expansion 1949: Enbridge liquid pipeline in Canada 1958: TransCanada gas pipeline in Canada 1967: First Russian gas to Europe 1960s: Offshore pipeline technology through North

Sea and Gulf of Mexico development 1970s: Intelligent pigging technology development 1980s: Higher strength steels and automatic welding

technology development


Innovations Since 1950

Use of pigs to clean the interior of pipelines Batching of different products in a common

pipeline Cathodic protection to reduce corrosion Machines to construct pipelines and bend pipes X-rays to detect welding flaws


Innovations Since 1970

Trenchless construction with directional drilling Intelligent pigs to detect pipe wall corrosion,

cracks and other pipe flaws Automation of pipeline monitoring and controlling

with a SCADA system High strength steel pipe


Why Pipelines?

Producing areas are widely varying geographically. Distances between producing and consuming areas

are far apart. Transportation technology has been improved,

particularly in pipeline technology including design, construction and material, compared with oil or LNG tanker.

Transportation cost has been reduced significantly due to improvement in technology.


Advantages of Pipelines

Most cost effective and economical Safe and reliable means of transporting energy Less damaging to the environment More secure than the other modes Versatile and convenient for transporting various

products Highly automated Unaffected by weather

Representative Costs of Oil and Gas Transportation (US$/Mbtu)

0

1

2

3

4

5

800 1600 3200 4800 6400 8000

Distance km

US$

/MB

tu

Gas Pipeline - Offshore

Gas Pipeline- Onshore

LNG

Oil Pipeline

Oil Tanker

Source Dr. Murray


Types of Pipelines

Gathering lines in producing areas collect fluids, often in multi-phase, and transport to processing plants or tanks.

Transmission lines transport fluids, often in single phase, from processing plants, refineries or tank farms to city gates or local distribution lines.

Local distribution lines transport fluids to the end consumers.


Types of Pipelines(Fluid Mechanics)

Single phase liquid flow Single phase gas flow

Non-Newtonian fluids Multi-phase hydrocarbon mixture Multi-phase solid-gas mixture Multi-phase solid-liquid mixture

Flow of capsules


Types of Pipelines(Commodity transported)

Natural gas pipelines Oil pipelines for crude oil

Petroleum product pipelines Oil flow lines and gas gathering lines Special pipelines such as LNG and CO2 Water pipelines

Sewage pipelines Solid pipelines


Challenges

Pipeline security system to protect pipeline infrastructure: protection from terror activities and theft as well as emergency handling and recovery

Safe and efficient operations: dispatcher training, leak detection and risk mitigation, cost reduction, efficiency increase, and downtime reduction

Pipeline system integrity management: line inspection, defect and repair assessment, rehabilitation, etc.

Pipe material with higher yield strength: cost reduction and increase in transmission efficiency with high strength pipe such as X80, X100, and X120.


Types of Pipeline Ownership

Producer Operating Company: a producer builds and operates its own system

Joint Operating Company: several producers and pipeline company form an independent pipeline company transporting the producers petroleum products

Common Carrier: a separate company independent of producers, formed to satisfy the transportation services for multiple petroleum companies. It issues tariffs that apply to all fluid movements through the pipeline system.


Introduction

Definitions Pipeline components

Key Topics


Pipe and Pipeline

Pipe closed conduit made of steel, plastic or concrete

Pipeline a line of connected pipes with pumps or compressors, valves, control devices and other equipment/facilities required for operating the system

A pipeline transports a fluid (liquid or gas), mixture of fluids, solid, fluid-solid mixture, or capsules


Pipeline States

A pipeline state can be either steady or transient. A steady state is a condition of a system that does not change, while a transient state is a temporary oscillation that occurs in a system because of changes in flow and/or pressure.

Steady state simulations are simply pipeline models which do not change over time, while transient simulations are pipeline modes which can change over time.

Models can contain all types of standard pipeline equipment including pipes, pumps/compressors, valves, separators, etc.


Pressure Reference Pressure measurements are values relative to some

reference pressure or datum. Atmospheric pressure at mean sea level and standard

conditions is 101.325 kPa or 14.7 psia. Absolute pressure (kPa or psia) is measured relative to a

perfect vacuum which is 0.0 kPa or psia. This datum is fixed and never changes.

Pressure measuring devices measure pressure in terms of the surrounding pressure. This type of measurement is known as gauge pressure. Gauge pressure (kPag or psig) is the pressure relative to the surrounding pressure.


Pressure in Pipeline

As pressure is applied to the fluid at one end of the pipe by means of a pump and fluid flow is prevented by the closed valve, the pressure increases equally throughout the system.

If the valve is opened, the fluid will begin to flow out the open end of the pipe and the pressure at the end of the pipe will decrease.

The higher the pressure applied by the pump, the higher the flow rate of the fluid. As flow increases, the velocity of the fluid will increase as well.


Pressure in Pipeline - Continued

Fluid velocity will cause viscous shear stress to develop within the liquid and turbulence that occurs along the pipe walls due to pipe surface roughness.

Resistance to flow develops due to the viscous shear stress, causing a loss of pressure along the pipe in the direction of flow. This pressure loss due to friction is also called friction loss.

The friction loss, or pressure loss, for a given pipeline depends on the characteristics of the liquid viscosity, size of the pipe, fluid velocity, roughness of the pipe's interior surface, and the length of travel.


Temperature

Temperature affects pipeline capacity both directly and indirectly. Operating temperature can affect other terms in equations used to calculate the capacity of liquid lines.

Thermal expansion is the property of liquids to expand as their temperature rises.

Liquid density decreases with temperature increases, and lower density will reduce friction pressure losses.

Liquid viscosity decreases with temperature increase, and lower viscosity will reduce friction pressure losses.


Introduction Definitions

Pipeline components Pipe

Joints and Fittings

Valves

Scrapers Storage and Tank

Meter Station

Pump Station

Key Topics


Components of Pipeline System

Pipes Valves, joints and fittings Scrapers (pigs) Pump station

Prime movers and drivers Heater, cooler or chiller

Meter station Storage

Tanks Storage caverns Booster pumps

Control system Instrumentation SCADA, PLC and RTU


Key Topics

Pipes Joints and Fittings

Valves Scrapers Storage and Tanks Meter Station

Pump Station


Types of Pipe

Metallic pipes: Steel pipes Ductile-iron pipes Stainless pipes Copper pipes, etc.

Non-metallic pipes Concrete pipes Plastic pipes, etc.

Tubings


Metallic Pipes

Metallic pipes are stronger and harder to break, but they are more conductive to electricity and less corrosive-resistant than non-metallic pipes.

Metallic pipes that are most popular for transmission lines are steel pipes.


Steel Pipes

Steel pipes are made of carbon steel. They may be either seamless or welded.

The seamed steel pipes are made of steel sheets or steel plates rolled or press formed into circular shape, with the seam of each pipe closed by welding. Electric arc weld is most popular for large pipes.

A seamless pipe is made by piercing a cold rod through a hot rod of steel at a temperature of the order of 1,100oC.


Non-Metallic Pipes

Nonmetallic pipes are not as strong as metallic pipes structurally.

They may be lighter in weight, more economical, or may have certain other advantages such as being more corrosion resistant.


Concrete Pipes

Concrete pipes can be made to withstand moderate to high internal pressure by placing reinforced concrete, and are used extensively in water and wastewater works.

They have the advantages of being structurally strong, corrosion-resistant and economical.

Their disadvantages include being heavy (and hence being costly to transport and difficult to move), hard to cut (hence must be used in standard lengths), and more limited in the kinds of joints that can be used.


Plastic Pipes

Plastic pipes are used for water, wastewater, natural gas, and certain other fluids that do not dissolve or chemically interact with the plastic material.

They are low cost, lightweight, easy to cut and join, and corrosion resistant. Due to these advantages, plastic pipes are being used increasingly.

However, they are usually not as strong as metal pipes, deform easily, expand greatly as a result of temperature changes, soften or burn at high temperature, and become brittle in very cold weather.


Tubings

Tubings are similar to pipes except that they are normally smaller in diameter, and have thinner walls than those of pipes.

Although there is an overlap of the size of tubings with pipes, their designations are different (e.g., a 4-inch tubing does not have the same inner or outer diameter of a 4-inch pipe).

Due to this difference, fittings and valves for pipes cannot be used for tubings without some modification of either the tubing or fitting (or valve connection).


Key Topics

Pipe Joints and Fittings

Valves Scraper Storage and Tank Meter Station

Pump Station


Joints

Welded joints include welding for steel pipe, or fusing of plastic pipes.

Threaded joints are used for connecting threaded pipe sections together, or connecting a threaded pipe to a threaded coupling or fitting.

Flanges are the most common way to provide a strong joint without permanently joining the pipe sections together as done in welding. They are used extensively for steel pipe at both the inlet and

the outlet of pumps, valves, flow meters, and other fittings. Use of flanges allows such devices be easily installed in the

pipeline and easily disconnected from the pipe.


Flange Joint


Fittings

Screwed pipe fittings are used with threaded pipes, while welding fittings are used with non-threaded pipes.

Types of fittings and their purposes include: Coupling to connect two threaded pipes of the same size

together Bushing to connect a threaded small pipe to a larger one Reducer to change (reduce or enlarge) pipe diameter Elbow to change flow direction Cap to seal the end of a pipe Plug to seal the end of a threaded pipe Cross, tee, etc.


Key Topics



Pump Station


Types of Valves

Globe valve Gate valve Ball valve Plug valve Butterfly valve Check valve Pressure regulating and control valves Pressure relief valve


Valves A valve is a device that controls flow or changes the

direction of flow in a pipeline. When a valve is fully open, flow is not restricted. When a valve is partially opened, it has a throttling effect on

the fluid flow. When a valve is closed, no fluid can flow through the pipeline.

Valve types can have linear or rotary spindle movement: Linear types include globe and gate valves. Rotary types include ball valves, butterfly valves, plug valves

and their variants. Standards for valves are API 6D Pipeline Valves, Gate,

Plug, Ball, and Check Valves, and API 600, 602, 603: Valves.


Valve Applications

Globe, gate, plug and ball valves: main line, pump stations, and tank farms to control flow or change flow directions

Check valves: pump stations and tank farms to prevent backflow and separate the suction piping from the discharge side of a pump installation

Pressure regulating and control valves: reduction of the delivery pressure to third-party pipelines and of the pressure in downstream section of a piping system

Pressure relief valves: protection of piping systems and facilities from overpressure due to upsets in operational conditions


Globe Valve

Globe valves consist of a movable disk-type element and a stationary ring seat in a globe shaped body.

Globe valves have a smooth stem and are opened and closed by an actuator assembly. When a globe valve is manually operated, the stem is turned by a handwheel.

Flow changes direction as it goes through the valve. Consequently, large pressure loss is generated even when the valve is fully open.

Globe valves are used for applications requiring throttling and frequent operation.


Globe Valve Diagram


Gate Valve A gate valve is closed and opened by turning the

handle connected to it, which raises or lowers a stem (shaft) connected to the gate.

It takes many turns to completely open or close a gate valve. The pressure loss of the valve is small, when the gate is fully open.

The gate valve used in oil or natural gas pipelines has a conduit with a full round bore for smooth passage of scrapers.

Gate valves normally have flanged ends which are drilled according to pipeline compatible flange dimensional standards.


Gate Valve Diagram


Ball Valve

The gate of a ball valve is a large bead (i.e., a large sphere having a central piercing).

The gate is turned from a completely closed to a fully open position in 90o. When fully open, it causes little blockage to the flow and hence has little pressure loss.

Ball valves are durable and usually work to achieve perfect shutoff. Therefore, they are used for on-off operations.

V-port ball valves can be used for throttling or controlling pressure.


Ball Valve Diagram


Plug Valve

Plug valves are valves with cylindrical or conically-tapered "plugs" which can be rotated inside the valve body to control flow through the valve.

The plugs in plug valves have one or more hollow passageways going sideways through the plug, so that fluid can flow through the plug when the valve is open.

Plug valves are simple and often economical, and are good for open/close operations.


Plug Valve Diagram


Butterfly Valve

A butterfly valve uses a center-pivoted flat circular plate as a gate.

The plate is always present within the flow, therefore a pressure drop is always induced in the flow regardless of valve position.

It must be closed slowly or else the valve can be damaged easily.

This is the most economical type for use in large pipes. A butterfly valve is a type of flow control device,

typically used to regulate a fluid flowing through a section of pipe.


Butterfly Valve Diagram


Check Valve

A check valve is installed to prevent flow reversal, so that it produces unidirectional flow.

Flow should not reverse through a pipe during transients to protect metering and pumping equipments and to reduce transients.

Three types of check valves are swing check valve (horizontal or vertical lift types), tilt disk check valve (does not slam), and ball check valve.


Check Valve Diagram


Pressure Relief Valve

The pressure relief valve or safety valve is a small valve mounted on the wall of a pipe. It is usually a spring-loaded valve with the spring preset to value to withstand certain pressure.

When the pressure in the pipeline is within the preset value of the valve, the valve is closed, and it has no influence on the flow in the pipe. However, when the pressure in the pipe rises beyond the preset value, the spring is pushed back by this pressure and the valve is opened.

The open valve draws a portion of the flow away from the pipe, which in turn causes the pressure in the pipe to fall and reduce the dangerous pressure surge.


Pressure Relief Valve - Continued

Safety valves are good protection against slowly rising pressure in the pipe, but not effective in protecting rapid rise of pressure large surges.

Because pressure relief valves alone cannot guarantee the safety of a piping system, other devices such as pressure regulating valves (PRV) may be necessary.

Applicable codes include ASME Boiler & Pressure Vessel Code, Section VIII Division 1 and Section I, ISO 23251, API Standard 521, etc.


Operation of Pressure Relief Valve

Pipe to be protected

Pressure relief valve

Flow

To drain or reservoir


Surge Tanks

A surge tank is a tank connected to a pipeline for reducing the high pressure generated by the pressure surge or water hammer.

When pressure in the pipe rises, the liquid in the pipe enters the surge tank to damp out the pressure fluctuations in the pipe caused by the water hammer.

Surge tanks are often used in pipelines. They are placed at pumping stations on the discharge side of the pumps and at the end of a long pipeline upstream of a valve.


Surge Tanks

Check valve

Simple Surge Tank

One-way Surge Tank


Pressure Regulating Valve

Unlike the safety valve which is a small valve mounted on the pipe wall and can affect only a small portion of the flow through the pipe, the PRV is mounted in the main pipe.

Because the entire flow in the pipe passes through the PRV, operation of the PRV has a strong impact on the pipe flow and the pressure in the pipe.

Pressure regulating valve (PRV) is an automated special valve mounted in a pipeline to regulate the pressure in the downstream of the regulator.


PRV - Continued

It maintains the pressure within a predetermined range. The main valve (control valve) of a PRV is partially closed under normal flow conditions, so that it can either be closed more, or opened more, on demand.

The valve is controlled by the PRV outlet (or downstream) pressure. When the outlet pressure exceeds a preset value, the valve will close more until the outlet pressure has dropped to below the preset value. On the other hand, when the downstream pressure is lower than the preset value, the valve will open more to allow more flow through the pipe, causing the downstream pressure to rise.


PRV - Continued

This feedback mechanism keeps the downstream pressure approximately constant.

For most commercial PRV system, the energy to open and close the control valve comes from the flow itself. The outlet pressure is utilized to drive the valve; no outside energy is required. In large system, an electrical motor is used to drive the valve, controlled by sensors and electronics.

An important application of PRVs is the reduction of natural gas pressure in distribution lines before they enter a home or other building.


Pressure Regulating Valve

Flow

Pipe segment to be protected

Pressure regulating valve


Key Topics


Valves Pigs or Scrapers Storage and Tank Meter Station

Pump Station


Pigs

Pigs or scrapers are special devices that are sent into a pipeline for cleaning or inspecting the pipe interior, etc.

Types of pig are: Cleaning pig removing debris, scale, water and other fluids

to reduce pipe roughness and increase product quality Caliper pig gauging the pipe interior diameter to determine

if there is any collapsed or kinked pipe Batching pig separating different batches of liquid products

being transported through the same pipeline Inspection pig allowing the pipe interior to be observed to

measure pipe diameter and wall thickness The pigging system includes the pig or scraper, pig

launcher and receiver.


Pipeline Inspection Tools

Modern pipe inspection systems consist of a standard 5-6 finned scraper with an intelligent transmitter that has a global positioning system (GPS) fixed on it to tell the exact location of the scraper inside the pipeline while it is on the move.

Along with the GPS positioner there are a host of other instruments like the internal camera that takes live video of the pipe condition inside while the scraper is moving, the thickness gauge that constantly measures the thickness of the wall of the.


Pipeline Inspection Tools - Continued

As the inspection tool moves inside the pipe, data like the speed of the inspection tool, flow, rate of fluid inside, etc. is measured at regular intervals. So by the time the inspection process is over, the complete set of data for all the measurable parameters is ready outside.

This data is compiled and used for post inspection analysis about the condition of the pipeline from inside.


Magnetic Flux Leakage Detection

MFL tools are based on the principle of magnetic flux leakage. It can differentiate between internal and external corrosion and detect changes in nominal wall thickness.

A magnetic field is induced in the pipeline steel. If a flaw is present, part of this magnetic field escapes the wall. Extremely sensitive sensors detect and measure the resultant leakage field and allow the detection and sizing of metal loss and corrosion.

These inspection tools can accurately detect, size, and locate corrosion or any other anomalies in pipelines.

Once the problem is detected, the information can be used to develop a pipeline de-rating schedule, implement a repair or replacement program, etc.


Ultrasonic Inspection Tool

An ultrasonic inspection tools also monitors pipelines for corrosion. It uses ultrasonics to determine the pipe wall thickness.

The tool analyses the whole surface and length of the pipeline for traces of corrosion. This technique can be applied while normal operation of the pipeline is maintained without any significant reduction in pipeline flow.

The tool allows the determination of the extent, location, depth, and internal/external position of the corrosion.


Key Topics



Pump Station


Terminals

A terminal may consist of tanks, manifolds, meter stations, and booster pumps.

All crude or petroleum products entering a terminal flows through a set of manifolds, which are an array of pipes and valves that direct incoming fluids to designated facility at the terminal.

All crude and petroleum products are measured by the terminal meter banks before they enter the tanks.


Tank Farm

A tank farm is a facility for the storage of oil and/orpetroleum products, from which these products are usually transported to end users or further storage facilities.

A tank farm has tanks, either above ground or underground, and manifolds for the discharge of products into road tankers, barges or pipelines.

Tank farms are usually situated close to refineries or in locations where tankers containing products can discharge their cargo.

Some tank farms are attached to pipelines from which they draw their supplies and tanks can also be fed by other pipelines, rail, barge or road tanker


Storage Tank Petroleum products that have been separated and

treated is transported and stored in a cylindrical vessels.

Products enter the tank at the top with a flow line extending down into the interior of the tank.

A sales outlet line is placed about 30cm from the bottom of the tanks. Bottom drain outlet allows draining of BS&W.

The tank interior and exterior are treated to avoid corrosion.

Strapping tables are provided by the tank manufacturer to determine the volume of the tanks.


Underground Cavern

Underground caverns are used for storing petroleum liquids, particularly light petroleum liquids such as LPG.

Cavern pressure is maintained by injecting brine water below the petroleum liquid surface.

Salt caverns are frequently used for underground cavern.


Key Topics



Pump Station


Meter Station

A meter station is required at a location where custody transfer takes place.

A meter station consists of flow computer, meter run, piping, and valves.

A meter run includes measurement sensors such as flow, pressure and temperature, and other equipments such as straightening vane, strainer, and valves.


Key Topics



Pump Station


Pump Station

A pump station can be either lifting (injection) pump station or mainline pump station.

A mainline pump station consists of pumps, piping, measurement and valves, while a lifting station may have a meter station, storage tanks, and booster pumps.

A pump station may need a cooler, heater or chiller: If the fluid temperature is too high, coolers may be needed. If the fluid is too viscous, a heater may be required to lower

the viscosity. If the pipeline runs across permafrost zones, the fluid

temperature must be kept below zero and thus chillers are required.

1 Pipeline Overview

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