Introduction to Process Plant Layout & Piping Design

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INTRODUCTION TO PROCESS PLANT

LAYOUT & PIPING DESIGNThe objective of plant design is to define the equipment,

piping, instrumentation and process requirements neededto build and operate a process plant.

By equipment, we mean vessels, pumps, heat exchangers, etc.These are the most common type of equipment in chemicaland petrochemical plants, where most of the processstreams are gases or liquids. Other industries that deal withsolids use equipment like conveyors, Cyclones, and others

that will not be dealt with here. Vessels can be of manytypes, such as drums, tanks, reactors, phase separators,and distillation columns.


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PIPING DESIGN FUNDAMENTALSPiping is the physical elements that interconnect the equipment and in which the

process streams flow. Piping comes in different sizes and materials. It is the duty of the

process engineer to specify the size and materials of the piping and also the thermalinsulation, if required. The term piping also includes accessories such as elbows, tees,

valves, flanges, etc.The most common material is carbon steel. Other materials, such as varies grades of

stainless steel, and plastic materials, such as PVC, Teflon, are also used.Instrumentation are devices used to measure, control, and monitor the process

variables.These variables can be flow, temperature, pressure liquid levels, viscosity, and others.Control valves and relief valves are also an important part of the instrumentation.Plant design normally starts with a process scheme that is a known series of physio-

chemical operations that must be performed to go from the feed stocks to the desired

products. These operations are established during the process development stage,

normally in pilot plants, which are a small scale versions of the industrial plant.The most common operations are:Mixing two or more streams to obtain a homogeneous mixture.Splitting a stream in two or more streams of same composition.


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Heating or cooling stream to a given temperature.Vaporizing a liquid stream partially or totally.Condensing a vapor stream partially or totally.Adiabatically flashing a stream to a given pressure.

Exchanging heat between two streams.

Pumping a liquid stream.Compressing a vapor stream.Separating a stream into 2 or more streams in a series of vapor- liquid equilibrium (VLE).Reacting certain components of a mixed stream according to a predefined stoichiometry.

PIPING DESIGNPiping plant design is an essential part of successful plant operation. Many decisions must be made in

the design phase to achieve this successful operation, including:

Required fluid quantity to or from a process

The optimum pressure- temperature for the process

Piping material selection

Stress and nozzle load determination

Pipe support scheme


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PRINCIPALS OF PROCESS PLANT LAYOUT

PLOT PLAN Roads

Access

Storage

Admin

Utilities

PROCESS PLANT Roads

Access

Units

Buildings

PROCESS UNIT Access

Equipment


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PROCESS EQUIPMENT Spacing

Arrangement

IMPORTANT ISSUES IN LAYOUT General terrain

Safety and environment

Regulations, Native,

Flammable /non-flammable materials

High /Low pressure units

Wet / Dry systems Maintenance, Utilities

IMPORTANT SAFETY ISSUESIN PLANT LAYOUT Accident containment and avoidance of Domino effects

High hazard operations

Segregation of different risks Exposure to possible explosion over pressure

Exposure to fire radiation

Minimizing vulnerable piping

Drainage and grade sloping

Prevailing wind directions

Provisions for future expansion


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OVERALL PHILOSOPHY

Arrange units to provide:

Economical plant

Safe and easy to operate and maintain

Compactness in arrangement

Integrated in flow sequenceSpace provided for convenient operation and maintenance access

Planed expansion

HOUSED PLANTMultilevel

Vertical and horizontal arrangements important

Gravity flow possible Mobile crane-use in central aisle

Pipe rack locations and main access

Piping runs to change elevation on direction change

Ability to extend plant

Offices and control room

EQUIPMENT LAYOUT ISSUESPumps (NPSH, suction line, motor location)

Instrumentation(CVs accessible)

Heat exchangers(bundles, fin-fan vs. water)


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Flares(radiation levels, alternatives)

Solids (use gravity flow, Containment)

Expensive piping (Run lengths)

Reactors (catalyst dump)

Maintenance (access, removal)

MODULAR SYSTEMS Major savings in construction costs( 50%)

Require more detailed engineering design

Extra structural steel (30%)

Transportation costs (1-2% of module cost)

Small footprints possible

Ideal for small-scale plants


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We have just brought the pipes now we need to solve some more problems.

Pipes are all straight pieces.

Even some Pipes are of different sizes

We need some branch connections.

We need some bend connections.

Anyway, the pipes and fittings are in place, but the ends are yet to joined with the Tank nozzles.

We now have to complete the end connections

We need some arrangement to stop the flow if needed To control the flow in a pipe line we need to fit a special component, that is called- valve

Other than valves another important line component of pipe line is a filter, which cleans out

debris from flowing fluid. This is called strainer

When some fluid is flowing in a pipe we may also like know the parameters like, pressure,

temperature, flow rate etc. of the fluid.

To know these information we need to Install INSTRUMENTS in the pipeline

Here are some of the pipe supporting arrangements. There can be numerous variants. All

depend on piping designers preference and judgment.

PROCEDURE & WORK FLOW PHYSICAL QUANTITIES & UNITS


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PROCESS UNIT


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Access


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Equipment


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PROCESS EQUIPMENT


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Spacing


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Arrangement


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IMPORTANT ISSUES IN LAYOUT


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General terrain


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Safety and environment


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Regulations, Native,


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Flammable /non-flammable materials


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High /Low pressure units


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Wet / Dry systems


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Maintenance, Utilities


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Important Safety Issues in Plant layout


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Accident containment and avoidance

of Domino effects


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High hazard operations


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Segregation of different risks


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Exposure to possible explosion over

pressure


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Exposure to fire radiation


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Minimizing vulnerable piping


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Drainage and grade sloping


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Prevailing wind directions


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Overall Philosophy


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Arrange units to provide:


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Economical plant


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Safe and easy to operate and maintain


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Compactness in arrangement


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Integrated in flow sequence


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Space provided for convenient

operation and maintenance access


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Planed expansion


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Housed Plant


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Multilevel


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Vertical and horizontal arrangements

important


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Gravity flow possible


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Mobile crane-use in central aisle


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Pipe rack locations and main access

h l


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Piping runs to change elevation on

direction change


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Ability to extend plant


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Offices and control room

P (NPSH i li


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Pumps (NPSH, suction line, motor

location)


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Instrumentation(CVs accessible)

H t h (b dl fi f


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Heat exchangers(bundles, fin-fan vs

water)


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Flares(radiation levels, alternatives)


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Solids (use gravity flow, Containment)


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Expensive piping (Run lengths)


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Reactors (catalyst dump)


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Maintenance (access, removal)


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& Piping Design Fundamentals


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Piping is the physical elements that

interconnect the equipment and in

which the process streams flow. Piping

comes in different sizes and materials.

It is the duty of the process engineerto specify the size and materials of the

piping and also the thermal insulation,

if required. The term piping alsoincludes accessories such as elbows,

tees, valves, flanges, etc.


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The most common material is carbon

steel. Other materials, such as varies

grades of stainless steel, and plastic

materials, such as PVC, Teflon, are also

used.


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Instrumentation are devices used to

measure, control, and monitor theprocess variables.


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These variables can be flow,temperature, pressure liquid levels,

viscosity, and others. Control valves

and relief valves are also an important

part of the instrumentation.


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Plant design normally stars with a

process scheme that is a known series

of physic-chemical operations that

must be performed to go from the

feed stocks to the desired products.These operations are established

during the process development stage,

normally in pilot plants, which are asmall scale versions of the industrial

plant.


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The most common operations are:

Mixing two or more streams to obtain


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Mixing two or more streams to obtain

a homogeneous mixture.

Splitting a stream in two or more


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Splitting a stream in two or more

streams of same composition.

Heating or cooling stream to a given


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Heating or cooling stream to a given

temperature.

Vaporizing a liquid stream partially or


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Vaporizing a liquid stream partially or

totally.

Condensing a vapor stream partially or


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Condensing a vapor stream partially or

totally.

Adiabatically flashing a stream to a


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Adiabatically flashing a stream to a

given pressure.

Exchanging heat between two


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Exchanging heat between two

streams.


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Pumping a liquid stream.


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Compressing a vapor stream.

Separating a stream into 2 or more


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streams in a series of vapor- liquid

equilibrium (VLE).

Reacting certain components of a


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mixed stream according to a

predefined stoichiometry.


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Piping code


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In 1926 the American standardsinstitute initiated Project B31 develop

a piping code. ASME was the sole

administrative sponsor. A number ofseparate sections have been prepared,

most of which have been published.

The various sections designations


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The various sections designations

follow.


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B31.1 Power Piping

B31.2 Fuel Gas Piping (Withdrawn in


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B31.2 Fuel Gas Piping (Withdrawn in

1988)


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B31.3 Process piping.


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B31.4 Liquid Transportation System for

Hydrocarbons, Liquid Petroleum Gas,

Anhydrous Ammonia, and Alcohols.

B31 5 R f i i Pi i


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B31.5 Refrigeration Piping.

B31.6 Chemical Plant Piping (never


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B31.6 Chemical Plant Piping (never

published).

B31.7 Nuclear Piping(Moved to B&PV


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B31.7 Nuclear Piping(Moved to B&PV

Code Section III).

B31.8 GAS Transmission and


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3 .8 GAS Transmission and

Distribution piping Systems.

B31 9 B ildi S i Pi i


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B31.9 Building Service Piping.

B31.10 Cryogenic Piping (Never


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y g p g (

published).

B31 11 Sl Pi i


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B31.11 Slurry Piping.

B31.12 Hydrogen Piping (project


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y g p g (p j

started in 20004)

Plant Capacity in MTPY(metric ton per


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p y ( p

year)

Product specification in terms ofit i t t f t i


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purity maximum content of certain

inpurities,

Documents

Introduction to Process Plant Layout & Piping Design