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    Heat Exchanger Inspection PDF

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    reezman
    The document provides information about inspecting heat exchangers during manufacturing and operation. Key inspections during manufacturing include checking tube dimensions, bundle configuration, tube sheet dimensions, tube rolling, leak testing welds, and hydrostatic testing. Important in-service inspections include checking for corrosion of shells and tubes, measuring wall thickness, examining welds, and plugging or replacing degraded tubes. The inspections are aimed at verifying component integrity and safety.

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    Heat Exchanger Inspection PDF

    Uploaded by

    reezman
    127 views8 pages
    The document provides information about inspecting heat exchangers during manufacturing and operation. Key inspections during manufacturing include checking tube dimensions, bundle configuration, tube sheet dimensions, tube rolling, leak testing welds, and hydrostatic testing. Important in-service inspections include checking for corrosion of shells and tubes, measuring wall thickness, examining welds, and plugging or replacing degraded tubes. The inspections are aimed at verifying component integrity and safety.

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    The document provides information about inspecting heat exchangers during manufacturing and operation. Key inspections during manufacturing include checking tube dimensions, bundle configuration, tube sheet dimensions, tube rolling, leak testing welds, and hydrostatic testing. Important in-service inspections include checking for corrosion of shells and tubes, measuring wall thickness, examining welds, and plugging or replacing degraded tubes. The inspections are aimed at verifying component integrity and safety.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    127 views8 pages

    Heat Exchanger Inspection PDF

    Uploaded by

    reezman
    The document provides information about inspecting heat exchangers during manufacturing and operation. Key inspections during manufacturing include checking tube dimensions, bundle configuration, tube sheet dimensions, tube rolling, leak testing welds, and hydrostatic testing. Important in-service inspections include checking for corrosion of shells and tubes, measuring wall thickness, examining welds, and plugging or replacing degraded tubes. The inspections are aimed at verifying component integrity and safety.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 8

    Heat Exchanger Inspection

    The Heat Exchanger Inspection article provides you with information about
    the inspection of the heat exchanger and heat exchanger testing during the
    manufacturing phase, as well as in-service inspection in operating units.

    Shell and Tube Heat Exchanger Inspection in Manufacturing Shop

    The construction code for shell and tube heat exchangers is ASME Code
    Section VIII, and it covers the minimum requirements for design, materials,
    fabrication, inspection, testing, and preparation for initial delivery.

    After the 2003 addenda of ASME Code Section VIII Div. 1, the design of the
    shell and tube heat exchanger needs to be done based on Subsection C, in
    UHX part. The design based on TEMA, or any similar code might be
    accepted which meeting the requirements of UHX part.

    The heat exchanger still is a pressure vessel and all requirements for ASME
    pressure vessel does apply for heat exchanger as well. We are going to
    avoid to repeat those requirements for the heat exchanger. There are several
    inspection requirements that only apply to the heat exchanger and not
    regular pressure vessel:

    Tube Inspection - The tube outside diameter, inside diameter,


    thickness, and ovarlity shall be checked before the building of the
    tube bundle. You need to refer to ASME Section II to get the
    acceptance tolerances.

    For example, if your tube material is SA 179, you have to refer to


    the SA 179 and that will refer you to the SA 450 (Specification for
    General Requirements for Carbon, Ferritic Alloy, and Austenitic
    Alloy Steel Tubes) for acceptance tolerance. You have to use your
    caliper, machinist ruler, etc. to make these measurements and
    make sure the values fall within acceptance range.

    Tube Bundle Inspection - The bundle dimension shall be checked


    based on the approved drawing. The baffle diameter and distance
    between them shall be controlled and meet the acceptance
    tolerances in the drawing.

    The tightness of stay bolts and spacers must be controlled. The


    shell cleanliness needs to be verified and make sure the inside
    welds are complete and are ground as per drawing requirements.

    Tube sheet Inspection - The Tube sheet shall be inspected before welding
    to the shell. The whole diameter, grooves dimensions, drilling pattern, the
    thickness of the tube sheet and surface finish shall be measured and
    checked against acceptance tolerances in the approved drawing.

    Tube Rolling Inspection - The tube rolling shall be checked based on


    customer specification. The wall reduction (after rolling) and depth of roll
    shall be measured and shall meet the customer specification. The wall
    reduction should not be less than 5% and should not be more than 8% of the
    tube wall thickness.

    Leak Testing of Seal Weld (Tube to Tube sheet) - if seal welding


    considered, then the leak test will be a mandatory requirement. The shell
    side will be subjected to the air pressure, and water and soap solution will be
    sprayed to the tube sheet to make sure all seal welds are defect free. The
    bubble will be developed if there was any welding defect such as crack,
    pinhole, etc.

    Shell side Hydrostatic Testing - After manufacturing completion, the heat


    exchange shell side will be subjected to the hydrostatic testing. The test
    pressure amount shall be consistent with the value indicated in the approved
    drawing. The holding time shall be based on the supplier approved test
    procedure.

    The pressure gages calibration and range shall be controlled. The pressure
    gage range shall be within 1.5 thru 4 times of test pressure. The shell body
    and welding seams shall be inspected. The tube sheet also shall be checked.
    No leakage is allowed.
    The test pump hose shall be disconnected, and no pressure drop is allowed.
    The test result will be satisfactory if no leakage being observed and no
    pressure being dropped while the shell side was under pressure.

    Tubeside Hydrostatic Testing - After successful completion of shell side


    hydrostatic testing, the bonnets are assembled, and tube side is subjected
    to hydrostatic testing. Similarly, the amount of test pressure shall be as the
    one indicated in the approved drawing. Other requirement is similar to the
    shell test. No leakage and pressure drop shall be observed while the tube
    side is under pressure.

    Shell and Tube Heat Exchanger Application

    Shell and Tube heat exchangers are the most popular type in the industry.
    This type is made from 3 components as listed below:

     Two heads (one rear head, and the other one stationary head)
     Shell
     Tube

    One fluid is in the tube side and the other one in the shell side. The heat
    transfer is done through the tube wall.

    So your heat exchanger with more tubes will have more heat transfer
    surfaces, and at the same time will have a higher heat exchanger diameter.

    There are different kinds of shell and tube heat exchangers with different
    applications. The reason for the high amount of applications is that they are
    easy to maintain.

    Besides, the shell and tube heat exchanger is the only type that can be
    designed and operated at a temperature greater than 360 degrees
    centigrade, as well as in pressure higher than 30 bar.
    In-Service Inspection of Shell and Tube Heat Exchanger

    The In-Service Inspection code for shell and tube heat exchangers is API
    STD 510. The other API recommended practices and codes also have to be
    used in with this Code.

    Some of these Recommended Practices are API RP 572, API RP 577, and
    API RP 571, and also construction code sections might be used, such as
    ASME Code Section VIII and ASME Code Section IX.

    For repair, the requirement of API STD 510 or ASME-PCC-2 needs to be


    met. The title of ASME-PCC-2, which was first published in 2006, is: “Repair
    of Pressure Equipment and Piping.”

    Please note: if your shell and tube heat exchanger is “U” stamped and you
    need to do the repair, you have to use a Repair Organization holding an “R”
    Stamp from the National Board Inspection Code.

    The API 510 Pressure Vessel Inspectors are qualified persons to perform
    shell and tube heat Exchanger inspection.

    What are the Important Items in the Shell and Tube Heat Exchanger
    Inspection in Overhaul?
    Shell and Tube Heat Exchanger Inspections are categorized in the following way:

    Shell and Structure in Heat Exchanger Inspection:


     Neutralization of Austenitic Stainless Steel shell, clads, liner or weld
    overlay, which contains H2S service. The process needs to be done
    based on approved procedures by a corrosion engineer.
     Neutralization is also required for shell material with admiralty brass
    to reduce the risk of SCC.
     Neutralization of thermocouples, if necessary, and doing dye
    penetration test
     Sampling from shell fouling and corrosion products and making lab
    analysis and making interpretation by corrosion engineer (if
    necessary)
     Cutting small area of insulation sheet and removing the insulation and
    doing visual inspection for any sign of corrosion under insulation
     Thickness measurement of different parts of shell and shell nozzles
    and making corrosion rate and remaining life calculation
     Inspection of shell cleaning and approval i.e. water jetting etc.
     Checking inside surface for any cladding, liner failure or separation
     Inspection of Shell flange gasket seating area for any erosion,
    damage and cracking
     Inspection of longitudinal and circumferential weld joints, inlet and
    outlet nozzles, reinforcement pads and small bore connections for
    any crack, corrosion and mechanical damage and deformation
     Dye penetration test on weld joints that are susceptible to cracking,
    austenitic flange face, weld overlay and cladding surface and
    exchangers exposed to amine and caustic
     Hydrogen blistering inspection in hydrogen services (hand lamp
    procedure)
     Heat exchanger support, steel structure, foundation, bolt and nut
    inspection

    Bonnet in Heat Exchanger Inspection

     Thickness measurement and making corrosion rate and remaining life calculation
     Girth flange inspection for corrosion and erosion
     Internal surface inspection for corrosion and fouling
     Painting inspection of external surface
     Dye penetration or magnetic particle examination of weld joints susceptible to
    cracking

    Tube Bundle in Heat Exchanger Inspection

     Taking care in the pulling out of tube bundle to avoid any mechanical
    damage
     Sampling from tube side fouling and corrosion products and making
    lab analysis and making interpretation by corrosion engineer (if
    necessary)
     Controlling of water jetting or lancing cleaning process
     Controlling wire brushing process of inner tube edge and rolling area
    (preparation for ID measurement)
     Inside diameter measurement in tubes and tubes rolling areas
     Rate off and accordingly plugging the tubes when their OD reaches to
    the ID plus one thickness
     Retubing of tube bundle if more than 10% of tubes reach the above
    rejection limit
     Inspection from tube bundle components such as tubesheet, tube, tie
    rods and spacers, transfer baffles or support plate, impingement baffle,
    floating head flange and floating head backing device
     Inspection from internal surface of tubes for corrosion and fouling
     Pulling out a sample tube for sectioning and corrosion anlaysis if
    necessary
     Retubing when sectioning result proves the thickness is half of the
    nominal value
     Visual inspection and dye penetration test from tube to tubesheet seal
    or strength weld
     Eddy current testing if it is necessary
    Channel in Heat Exchanger Inspection

     Thickness measurement and making corrosion rate and remaining life


    calculation
     Inspection of gasket seating area, pass partition and nubbing for
    corrosion and deformation
     Inspection of internal surface for fouling, corrosion and soundness of
    linings (if any)
     Balance hole inspection for corrosion and erosion
     Welding joints inspection for any possible cracks
     Reinforcement pad inspection and doing soap test if necessary
     Cathodic protection anodes inspection and replacement if necessary
     Diaphragm and division box visual inspection and dye penetration test
    of diaphragm for any possible cracks (for high pressure exchangers)

    Channel Cover in Heat Exchanger Inspection

     Thickness measurement and making corrosion rate and remaining


    life calculation
     Inspection of gasket seating area for corrosion and deformation
     Inspection for internal surface for fouling, liner, cladding and coating
    soundness
     Soap test in channel cover with liner
     Lifting lug weld joint inspection for any possible crack

    Floating Head Inspection:

     Thickness measurement and making corrosion rate and remaining life


    calculation
     Inspection of gasket seating area, pass partition and nubbing for any
    possible corrosion and deformation
     Girth flange weld joint inspection for any possible crack and corrosion
     Internal surface inspection for corrosion and fouling and soundness of
    liner, coating and cladding (if any)

    Expansion Joint Inspection


     The heat exchangers with expansion joints need to be inspected for:
     Flange inspections for corrosion and erosion
     Inspection from internal surface for corrosion and erosion
     Air test
     The tube and shell hydrostatic test need to be done after the above stated
    inspection activities.

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