CM4120 Unit Operations Lab Piping Systems

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CM4120Unit Operations LabPiping Systems

• Piping Systems in the Chemical Process Industries
• March, 2008
• Introduction
• Basis for Design
• Piping Codes and Standards
• Design of Process Piping Systems
• Joints and Fittings
• Valves

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CM4120Unit Operations LabPiping Systems

• Piping Systems include
• Pipe
• Flanges
• Fittings
• Bolting
• Gaskets
• Valves
• Hangers and supports
• Insulations, coverings, coatings

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CM4120Unit Operations LabPiping Systems

• Piping systems are like arteries and veins. They
  carry the lifeblood of modern civilization.
• Mohinder Nayyar, P.E.
• Piping Handbook, 7th ed.
• McGraw-Hill, 2000

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CM4120Unit Operations LabPiping Systems

• Primary Design Consideration is Safety
• Evaluate Process Conditions
• Temperature
• Pressure
• Chemical compatibility/Corrosion allowances
• Vibration, flexing, bending
• Expansion/Contraction due to temperature change
• Environmental conditions
• Evaluate the Effects of a Leak
• Evaluate Performance in a Fire Situation

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CM4120Unit Operations LabPiping Systems

• Secondary Considerations
• Evaluate any Special Requirements
• Sanitary requirements Cleanability
• Serviceability ease of maintenance of equipment
• Possible contamination of process fluid by piping
  materials, sealants, or gasketing
• Earthquake, Hurricane, Lightening, Permafrost
• Lowest Cost over the Lifetime

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CM4120Unit Operations LabPiping Systems

• Piping System Design Criteria
• 4 areas to consider
• Physical Attributes
• Loading and Service Conditions
• Environmental Factors
• Materials-Related Considerations

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CM4120Unit Operations LabPiping Systems

• Codes and Standards simplify design,
  manufacturing, installation process
• Standards provide design criteria for
  components
• standard sizes for pipe
• dimensions for fittings or valves
• Codes specific design/fabrication methodologies
• Incorporated into local/regional statute
• Its the LAW

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CM4120Unit Operations LabPiping Systems

• ASME Boiler and Pressure Vessel Code
• ASME B31 Code for Pressure Piping
• ANSI Standards dimensions for valves, piping,
  fittings, nuts/washers, etc.
• ASTM Standards for piping and tube
• API Specs for pipe and pipelines
• AWS, ASHRAE, NFPA, PPI, UL, etc.

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CM4120Unit Operations LabPiping Systems

• ASME B31 is the applicable standard for design of
  most piping systems in chemical plants
• B31.1 Power plant boilers
• B31.3 Chemical plant and refinery piping
• B31.4 Liquid petroleum transport
• B31.7 Nuclear power plant radioactive fluids

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CM4120Unit Operations LabPiping Systems

• ASME B31.3 Chemical Plant and Refinery Piping
  Code
• Includes
• Process piping in chemical and refinery plants
• Process piping in pharmaceutical and food
  processing
• Process piping in textile and paper plants
• Boiler piping

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CM4120Unit Operations LabPiping Systems

• ASME B31.3 covers
• Materials and design
• Fabrication
• Erection and assembly
• Support
• Examination, inspection, and testing
• Web reference www.piping-toolbox.com

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CM4120Unit Operations LabPiping Systems

• Standard Pipe Sizes
• Diameters are Nominal
• Sizes 12 and less, nominal size lt OD
• Sizes 14 and over, nominal size OD
• Wall thickness inferred thru Schedule
• Schedule P/S 1000
• Defined Schedules
• 5, 10, 20, 30, 40, 60, 80, 100, 120, 140, 160

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CM4120Unit Operations LabPiping Systems

• Standard Tubing Sizes
• Steel tubing
• Diameters are Actual OD
• Wall thickness is specified
• Refrigeration Tubing
• Single wall thickness available for each size
• Actual OD
• Copper Tubing Nominal sizes
• Type K, L, M

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CM4120Unit Operations LabPiping Systems

• Materials Metallic piping
• Carbon and low alloy steel
• Ductile
• Inexpensive and available
• Easy to machine, weld, cut
• Some drawbacks

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CM4120Unit Operations LabPiping Systems

• Materials Metallic piping
• Alloy Steels including Stainless Steels
• Good corrosion resistance
• More difficult to machine, weld, cut
• Some drawbacks

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CM4120Unit Operations LabPiping Systems

• Materials Metallic piping
• Nickel, Titanium, Copper, etc.
• Copper is used in residential and commercial
  applications and is widely available
• Other materials are expensive and difficult to
  machine, weld, join
• Some incompatibilities with each

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CM4120Unit Operations LabPiping Systems

• Materials Non-Metallic piping
• Thermoplastics
• Wide range of chemical compatibility
• Light weight
• Easily cut and joined
• Low temperature limits
• Need extra supports

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CM4120Unit Operations LabPiping Systems

• Materials Non-Metallic piping
• Fiberglass Reinforced Pipe
• Wide range of chemical compatibility
• Easily cut and joined
• Wider temperature limits than thermoplastics
• Thermal expansion similar to carbon steel
• Similar structural performance as carbon steel

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CM4120Unit Operations LabPiping Systems

• Materials Others
• Glass
• Concrete
• Lined or coated
• Glass
• Rubber
• Cement
• Teflon
• Zinc (galvanized pipe)
• Double Containment piping systems

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CM4120Unit Operations LabPiping Systems

• Piping Insulation
• Prevent heat loss/ gain
• Prevent condensation below ambient
• Personnel protection over 125oF
• Freeze protection outdoor cold climates
• Fire protection
• Noise control

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CM4120Unit Operations LabPiping Systems

• Fiberglass Insulation w/ Asbestos plastered
  fitting coverings

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CM4120Unit Operations LabPiping Systems

• Metal Jacketed
• insulation covering

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CM4120Unit Operations LabPiping Systems

• Heat Tracing
• Prevents flow problems in cold climates
• Freeze protection
• Loss of flow due to viscosity increase
• Prevent condensation in vapor lines
• Methods
• Electric
• Hot Fluids

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CM4120Unit Operations LabPiping Systems

• Piping Supports
• Prevent strain at connections
• Prevent sag
• Must allow for expansion/contraction
• Design for wind/snow and ice/earthquake
• Clearance for plant traffic and equipment

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CM4120Unit Operations LabPiping Systems

• Results of inadequate support

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CM4120Unit Operations LabPiping Systems

• Results of inadequate support Flixborough,
  England
• May, 1974 Leaking reactor removed from train of
  reactors and temporarily replaced with a section
  of pipe
• June, 1974 Supports collapse, pipe breaks
• 28 dead, 89 injured, 1800 houses damaged, 160
  shops and factories damaged, large crater where
  plant stood

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CM4120Unit Operations LabPiping Systems

• The Design Process a three step approach
• Design for Flow
• Find min. diameter to achieve desired flow
  velocity
• Design for Pressure Integrity
• Find min. wall thickness for process and external
  conditions
• Find appropriate rating of in-line components
• Re-check for Flow Criteria

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CM4120Unit Operations LabPiping Systems

• Design for Flow
• Determined by economics
• Piping system must provide reliable service for
  expected life
• Smallest diameter usually is lowest cost

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CM4120Unit Operations LabPiping Systems

• Typical design velocity Rules of Thumb when
  sizing piping...
• Water lines 5-7 ft/sec
• Pump discharge (d/2 4 ft/sec)
• Pump suction (1/3 discharge velocity)
• Steam d in 1000 ft/min
• Slurries gt min. entrainment velocity
• d I.D. of pipe in inches
• from Rase and Barrow, Project Engineering of
  Process Plants, John Wiley, New York, 1957.

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CM4120Unit Operations LabPiping Systems

• Next determine wall thickness
• Pressure Integrity Design method
• ASME B31.3,

tmmin. wall thickness Pdesign pressure,
psig DO.D. of pipe, in. Sallowable stress, psi
Eweld joint efficiency yfactor to adjust for
temp A addl thickness for corrosion, external
loads, etc.
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CM4120Unit Operations LabPiping Systems

• Finally re-check ID
• Select in-line components
• Determine insulation, coverings, coatings
• Design and locate supports and hangers

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CM4120Unit Operations LabPiping Systems

• Effect of Thermal Expansion
• Example
• Calculate the expansion per 20 length of 2,
  schedule 40 carbon steel steam line at boiler
  startup for a 100 psig steam service.
• athermal expansion coefficient
• for mild steel, a 6.6x10-6 in/inoF

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CM4120Unit Operations LabPiping Systems

• Temp of pipe at amb. cond. 70oF
• Temp of 100 psig sat. steam 338oF
• ?T268oF
• L20240
• expansion due to temperature
• increase is a L ?T
• (6.6x10-6in/inoF)(240in)(268oF)
• 0.42 in per 20 of pipe

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CM4120Unit Operations LabPiping Systems

• What force is exerted on the end restraints of
  that 20 pipe if it is rigidly installed (end
  restraints cant move)?
• sinternal stress due to ?T, and
• s a (?T)E
• E is the material property called Modulus of
  Elasticity, relationship between stress and
  strain
• E30x106 psi for low carbon steel

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CM4120Unit Operations LabPiping Systems

• s a (?T)E
• (6.6x10-6 in/inoF)(268oF)(30x106lbf/in2)
• 53,000 lbf/in2
• since sF/A, FsA
• where Fforce on end restraints
• Across sec. area of 2, sched 40 pipe

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CM4120Unit Operations LabPiping Systems

• A?(OD2-ID2)/4
• ?(2.3752-2.0672)/4
• 1.07 sq.in
• F sA
• (53,000 lbf/in2)(1.07 in2)
• Force on the end restraints 57,000 lbf
• or 28.5 tons

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CM4120Unit Operations LabPiping Systems

• Pipe Joints
• Threaded
• Welded
• Soldered/ Brazed
• Glued
• Compression
• Bell and spigot
• Upset or expanded

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CM4120Unit Operations LabPiping Systems

• Threaded joints

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CM4120Unit Operations LabPiping Systems

• Soldered joints

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CM4120Unit Operations LabPiping Systems

• Welded joints

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CM4120Unit Operations LabPiping Systems

• Compression joints

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CM4120Unit Operations LabPiping Systems

• Mechanical joints
• shown on glass drain piping system

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CM4120Unit Operations LabPiping Systems

• Pipe Fittings
• Forged
• Cast
• Malleable Iron
• Pressure/Temperature Rated by Class
• 125, 250, or 2000, 3000, etc.
• Need a look-up table to determine max. allowable
  P for the design temperature

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CM4120Unit Operations LabPiping Systems

• Fittings for joining 2 sections of pipe
• Coupling
• Reducing Coupling
• Union
• Flange

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CM4120Unit Operations LabPiping Systems

• Fittings for changing directions in pipe
• 45o Ell
• 90o Ell
• Street Ell

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CM4120Unit Operations LabPiping Systems

• Fittings for adding a branch in a run of piping
• Tee
• Cross

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CM4120Unit Operations LabPiping Systems

• Fittings for blocking the end of a run of piping
• Pipe plug
• Pipe cap
• Blind Flange

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CM4120Unit Operations LabPiping Systems

• Misc. pipe fittings
• Nipple
• Reducing bushing

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CM4120Unit Operations LabPiping Systems

• Gate Valve
• Used to block flow (on/off service)
• Sliding gate
• on knife-gate
• valve

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CM4120Unit Operations LabPiping Systems

• Globe Valve
• Used to regulate flow
• Cut-away shows
• stem seal
• plug
• and seat

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CM4120Unit Operations LabPiping Systems

• Ball Valve
• Typically used as block valve
• Quarter-turn valve
• Cut-away shows ball and seat

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CM4120Unit Operations LabPiping Systems

• Butterfly Valve
• Can be used for flow control or on/off
• Valve actuator/ positioner for accurate flow
  control

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CM4120Unit Operations LabPiping Systems

• Check Valves
• Used to prevent backflow
• Piston check
• Swing check

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CM4120Unit Operations LabPiping Systems

• References
• Piping Handbook, 7th ed., Nayyar, McGraw-Hill,
  New York, 2000.
• Piping Design for Process Plants, Rase, John
  Wiley, New York, 1963.
• Valve Handbook, Skousen, McGraw-Hill, New York,
  1998
• www.flowserve.com, Flowserve Corp., Sept. 2004.
• www.engineeringtoolbox.com, The Engineering
  Toolbox, Sept. 2004.