STD Spec for Shell and Tube Heat Exchangers

STANDARD SPECIFICATION Document n°:

10000-M50-210 Document title Rev:

SHELL AND TUBE HEAT EXCHANGERS

03M Date:

2015-06-10

Yara Project Office

Brussels This document shall not be reproduced, lent or

otherwise disposed of, without YPO written approval

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TABLE OF CONTENTS

1 SCOPE ............................................................................................................................. 3

2 NORMATIVE REFERENCES ........................................................................................... 3

2.1 (NEW) YPO STANDARD SPECIFICATIONS ....................................................................... 3 2.2 (NEW) ORDER OF PRECEDENCE .................................................................................... 3 2.3 (NEW) LANGUAGES UNITS ............................................................................................ 3

3 TERMS AND DEFINITIONS ............................................................................................. 3

4 GENERAL ........................................................................................................................ 4

5 PROPOSALS ................................................................................................................... 4

6 DRAWINGS AND OTHER REQUIRED DATA ................................................................. 4

6.1 OUTLINE DRAWINGS AND OTHER SUPPORTING DATA ...................................................... 4 6.2 INFORMATION REQUIRED AFTER OUTLINE DRAWINGS ARE REVIEWED .............................. 4 6.3 REPORTS AND RECORDS .............................................................................................. 5

7 DESIGN ............................................................................................................................ 5

7.1 (MOD.) DESIGN REQUIREMENT ..................................................................................... 5 7.2 CLADDING FOR CORROSION ALLOWANCE ....................................................................... 6 7.3 SHELL SUPPORTS ........................................................................................................ 7 7.4 STATIONARY HEAD AND FLOATING HEAD ....................................................................... 7 7.5 TUBE BUNDLE .............................................................................................................. 8

7.5.1 Tube ................................................................................................................... 8 7.5.2 Tube-sheets ....................................................................................................... 9 7.5.3 Baffles and support plates ................................................................................ 10 7.5.4 Impingement protection .................................................................................... 11 7.5.5 Bypass sealing devices .................................................................................... 11 7.5.6 Bundle skid bars ............................................................................................... 12 7.5.7 Tube-to-tube-sheet joint ................................................................................... 12

7.6 NOZZLES AND OTHER CONNECTIONS ........................................................................... 13 7.7 FLANGED EXTERNAL GIRTH JOINTS ............................................................................. 13 7.8 GIRTH FLANGE JOINT SUPPLEMENTARY DESIGN REQUIREMENT .................................... 14 7.9 EXPANSION JOINTS .................................................................................................... 15 7.10 GASKETS .................................................................................................................. 15 7.11 HANDLING DEVICES ................................................................................................... 15 7.12 REQUIREMENTS FOR HYDROGEN SERVICE ................................................................... 16

8 MATERIAL ..................................................................................................................... 16

8.1 GENERAL .................................................................................................................. 16 8.3 GASKETS ............................................................................................................... 16 8.4 TUBES ...................................................................................................................... 17

9 FABRICATION ............................................................................................................... 17




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9.4 TUBE ........................................................................................................................ 17 9.9 WELDING .................................................................................................................. 17 9.10 HEAT TREATMENT ...................................................................................................... 18 9.11 DIMENSIONAL TOLERANCES ........................................................................................ 19 9.9 TUBE HOLES ............................................................................................................. 19 9.10 TUBE TO TUBE SHEET JOINTS ..................................................................................... 19

10 INSPECTION AND TESTING ..................................................................................... 21

10.1 QUALITY CONTROL ..................................................................................................... 21 10.2 PRESSURE TESTING ................................................................................................... 22

11 PREPARATION FOR SHIPMENT .............................................................................. 23

11.1 PROTECTION ............................................................................................................. 23

12 SUPPLEMENTAL REQUIREMENTS ......................................................................... 23

12.1 GENERAL ............................................................................................................... 23

APPENDIX 1 – LEAK CLASS 1 ............................................................................................ 24

APPENDIX 2 – LEAK CLASS 3 ............................................................................................ 25




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1 SCOPE

This Engineering specification in conjunction with 10000-M50-211, “Pressurized Static Equipment” defines the minimum requirements for the design, material, fabrication, testing and shipping of shell and tube heat exchangers. This specification gives the amendments and supplements to API standard 660, ninth edition, March 2015, “Shell-and-Tube Heat Exchangers”. It is intended that API standard together with this specification shall be used for shell and tube heat exchanger equipment. For ease of reference, the clause or section numbering of API standard 660 has been used throughout this specification. Clause in API standard 660 not mentioned remain unaltered.

2 NORMATIVE REFERENCES

Abbreviations have been defined in section 3. (Del.) NACE MR0175 (all parts), Petroleum and natural gas industries — Materials for use in H2S-containing environments in oil and gas production (Del.) NACE MR0103, Materials Resistant to Sulfide Stress Cracking in Corrosive Petroleum Refining Environments (Mod.) TEMA Standards, Latest Edition, Standards of the Tubular Exchanger Manufacturers Association. This modification shall be applied throughout API 660, wherever is applicable. (New) HEI; Heat Exchanger Institute

2.1 (NEW) YPO STANDARD SPECIFICATIONS

10000-M50-211: Pressurized Static Equipment 10000-M50-187: Post Weld Heat Treatment

2.2 (NEW) ORDER OF PRECEDENCE

Refer to 10000-M50-211.

2.3 (NEW) LANGUAGES UNITS

Refer to 10000-M50-211.

3 TERMS AND DEFINITIONS

(New) In addition to terms and definitions stated in 10000-M50-211; for the purpose of this specification and attached documents, following terms shall be defined as follows:




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(New) means new additional mandatory requirements to API 660. (Mod.) means mandatory modification or additional requirement on the existing

requirement of API 660. (Del.) means not applicable requirements of API 660.

4 GENERAL

4.1 (Mod.) In applying this specification and the details related to the Equipment, the Contractor accepts full responsibility for the design, material choice if applicable, construction and conformance to the referenced specifications, regulations and to the requirements of the purchase order. Equipment technical specifications include individual Equipment design data for each item. The design data contains the basic information and special requirements needed for the design. 4.2 (Mod.) TEMA class shall be R, unless otherwise specified in technical Specification or data sheet. 4.12 (New) Any deviation from this specification or the API 660 standards needs prior written approval from PURCHASER.

5 PROPOSALS

5.1 (Mod.) Bidder may confirm full compliance with Purchaser data sheet instead of providing his own data sheet, if applicable. 5.5 (Mod.) Required items for test shall be included in base offer. 200% Spare gasket shall also be considered in base offer as minimum.

6 DRAWINGS AND OTHER REQUIRED DATA

6.1 OUTLINE DRAWINGS AND OTHER SUPPORTING DATA

(New) w) Heat exchangers with titanium components shall have the following statement on the outline drawing: "Titanium Equipment – DO NOT ALTERNATE without Approval of Purchaser." (New) x) Foundation loads table for empty, operating, and hydrostatic test weights, wind and earthquake loads, and bundle pulling loads.

6.2 INFORMATION REQUIRED AFTER OUTLINE DRAWINGS ARE REVIEWED

6.2.2. (Mod.) Weld maps, all welding specification procedures and qualifications (including tube-to-tubesheet welding procedures and qualifications), NDE Maps and all supporting test results such as impact tests, hardness tests, corrosion tests, mock-up test, simulated PWHT as applicable, shall be submitted for Purchaser and NoBo / ASME inspectorate approval, prior to welding commencement.




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6.2.3. (New) new clauses: l) Vacuum design requirements; m) Stress relieving requirements for U-tubes shall be included in the U-tube bend drawing; n) Special hydrotest requirements, shipping or storage requirements.

6.2.4.(a) (New) Following calculation shall also to be done;

1) Actual and allowable tube-to-tubesheet loadings for fixed tubesheet exchangers 2) Pass partition plate and longitudinal baffle thickness calculations; 3) Expansion joint calculations as per design code 4) The static head due to the liquid level in exchangers (test and operating case, whichever has the higher fluid density) shall be included in the thickness calculations for design pressure at the coincident design temperature.

6.2.4 (c) (New) Table of required bolt loadings (bolt torque, bolt stress, and axial force values) for exchanger girth flange, channel cover flange, floating head flange bolting and bolt sizes more than 1 1/2” shall be presented in bolt tensioning procedure. 6.2.5 (Mod.) Design calculations for heat exchanger supports, lifting devices, and pulling devices shall be submitted. 6.2.7 (New) The Supplier shall submit the Inspection and Test Plan for review and approval. Inspection requirements and action for parties will be identified by the Purchaser in PIM meeting or during detail design document review.

6.3 REPORTS AND RECORDS

(Mod.) In addition to below mentioned documents, all required documents as per technical specification of equipment shall be provided by Supplier. (New) n) Tube expansion / tube wall reduction values be recorded on a tube layout drawing and included in the Manufacturer’s data book

7 DESIGN

(New) The design shall comply with all relevant chapters of 10000-M50-211 (Pressurized Static Equipment).

7.1 (MOD.) DESIGN REQUIREMENT

7.1.1 (Mod.) In case of no data for minimum metal design temperature in project data; minimum ambient temperature shall be considered as MDMT.




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7.1.3 (Mod.) In case of thermal design is part of Contractor/Supplier scope; for floating head exchangers with a single tube pass and tailpipe, and for all fixed tube-sheet exchangers, the need for an expansion joint shall be determined by the Supplier based on the operating cases specified on the equipment data sheet /technical specification. In addition, all alternate and upset operating cases shall be considered in design by Supplier. In case of thermal design is not part of Contractor/Supplier scope; all cases which have been specified in data sheet/technical specification shall be taken into account for mechanical design of heat exchanger. 7.1.4 (New) The corrosion allowance shall be applied to all components in contact with the process fluids, except for the bundle tubes. 7.1.5 (New) All non-pressure parts of the heat exchanger shall be designed and constructed according to TEMA class R, unless otherwise specified. 7.1.6 (New) If vibration calculation is part of Supplier scope, Supplier is responsible for providing a design free of damaging due to flow induced bundle vibrations for the flow and the density given in the exchanger specification. 7.1.7 (New) Leakage class of equipment depend on its criticality and services has been defined in equipment data sheet or technical specification. Three leak classes are defined as following: Class 1 Exchangers in critical services and materials (Appendix-1) Class 2 General process heat exchangers which are not indicated in class 1 or 3. Class 3 Low risk, low cost heat exchangers. (Appendix-2) For equipment in leakage class 1 and 2 following requirements are mandatory:

1- Forged tube sheet with integrally butt weld connection. 2- 100% volume NDT possible for all shell and channel welds. 3- 100% volume NDT possible for tube to tube-sheet welds, unless otherwise

approved in written by Purchaser.

7.1.8 (New) Steam surface condensers shall also comply with the standards for steam surface condensers according HEI (Heat Exchanger Institute).

7.2 CLADDING FOR CORROSION ALLOWANCE

7.2.1 (Mod.) The thickness of the corrosion resistant cladding/overlay shall be as per project specification data and this thickness shall not be considered in strength calculation. 7.2.2 (Mod.) If weld overlay in CRA(Corrosion Resistant Alloys) material shall be applied, it shall be at least in two layers and thickness of weld overlay shall not be less than 6 mm after machining, last 3 mm shall have the same chemical composition as the one of the CRA; chemical composition test and corrosion test shall be performed on actual overlay.




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7.2.3 / 7.2.4 (Mod.) In case of clad plate, thickness of clad shall not be less than 5 mm (for titanium or zirconium minimum thickness shall be 8 mm) , unless otherwise specified in technical specification. 7.2.6 (New) Where corrosion-resistant cladding (or weld overlay) is specified, it shall be applied to all wetted surfaces (in contact with process fluid), including gasket grooves. Pass partition plates shall be of the same alloy as the cladding material. 7.2.7 (New) Non-integral bonded (loose) liners shall not be used unless approved by the Purchaser.

7.3 SHELL SUPPORTS

7.3.1. (Mod.) Contractor shall verify that number and size of anchor bolts are adequate for the bundle pulling load. For stacked exchangers the fixed shell support and anchor bolts of the lower exchanger shall also be designed to withstand the longitudinal force applied at the centerline of the upper heat exchanger bundle. 7.3.2 (New) f) Saddles shall protrude beyond the bottom nozzles, including the drain nozzle with blind flange, by at least 50 mm to prevent damage to flange facings during transport, storage and maintenance, unless otherwise specified by Purchaser. 7.3.5 (Mod.) For horizontal heat exchangers, slotted holes shall be provided in the baseplate of all but one of the saddles, to allow for longitudinal movement due to thermal expansion or contraction. The width of the slot shall be equal to the anchor bolt diameter plus 8 mm. The length of the slots shall be equal to the anchor bolt diameter, plus twice the thermal expansion of the shell (based on the shell side design temperature) plus 8 mm. 7.3.7 (Mod.) Earthing lugs shall be as per 10000- M50-211. 7.3.8 (New) Flange bolting on connections between stacked shells shall be removable from one side of the flange without removing the top shell.

7.4 STATIONARY HEAD AND FLOATING HEAD

7.4.2 (Mod.) Pass partition plates (in both stationary heads and the floating heads) shall be designed, per TEMA paragraph RCB-9.132, without corrosion allowance, to accommodate at least three (3) times the maximum calculated clean pressure differential across each pass partition plate. In no case shall the minimum thickness be less than the value specified in TEMA paragraph RCB-9.131. The use of rods, bars, etc. to stiffen pass partition plates is acceptable. Calculations of the maximum allowable differential pressure across the pass partition plate shall be submitted in the mechanical design calculations.




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7.4.6 (Mod.) Floating heads shall be in accordance with Figure 1 (b) with full penetration welds or (c). In case of welded construction, weld shall be fully inspected by radiography or ultrasonic test. 7.4.7 (Mod.) Except for clad or weld overlaid construction, floating head flanges shall be provided with 3 mm (1/8 in) additional thickness to provide a future machining allowance on the gasket contact seating surface. The additional thickness shall not be used in the calculation of the maximum allowable working pressure. 7.4.9 (New) Floating heads shall be through-bolted. Use of bolts which are threaded into tapped holes in the floating tube-sheet is not permitted. 7.4.10 (New) Divided floating heads shall not be used. 7.4.11 (New) The backing ring for split ring floating heads shall conform to TEMA Figure RCB 5.141, style A. 7.4.12 (New) Integral shell covers shall be used on all sizes of U-tube and multi-tube pass pull-through floating head exchangers. 7.4.13 (New) For TEMA ‘B’ type bonnets, tube-sheets shall extend to the same diameter as the connecting flange and allow for independent hydrostatic test of both the shell and tube sides, without the use of a test ring. 7.4.14 (New) Channel covers used with clad or weld overlaid channels shall also be clad or weld overlaid. Loose-lined covers or solid alloy covers shall not be used unless otherwise specified in technical specification. 7.4.15 (New) Drain holes shall be provided in pass partition plates to facilitate drainage. Drain holes shall have a maximum diameter of 6 mm. The location, size, and number of drain holes shall be indicated on the fabrication drawings and subject to the approval of the Purchaser. 7.4.16 (New) The partition plates for channels and bonnets in high pressure heat exchangers shall be bolted on welded supports to channel/bonnet. Gaskets shall be provided between partition plates and supports

7.5 TUBE BUNDLE

7.5.1 Tube

7.5.1.2 (Mod.) Copper and copper alloys shall not be used, unless otherwise approved by Purchaser




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7.5.1.4 (Mod.) In case services with mechanical cleaning requirement on the tube side; the mean radius of U-bends shall not be less than two (2) times the nominal outside diameter of the tube. Where 22% Cr grade duplex stainless steel or titanium U-tubes are specified, the minimum bend radius shall not be less than 3.3 times the nominal outside diameter of the tube. 7.5.1.8 (New) Tubes shall be designed for design pressure on both sides for shell side and tube side (buckling check) design pressure. 7.5.1.9 (New) Welded tube shall not be used, unless otherwise approved by Purchaser. 7.5.1.10 (New) All exchanger tubes shall be cold drawn.

7.5.2 Tube-sheets

7.5.2.1 (Mod.) Using collar or drilled-and-taped holes are subject to Purchaser approval, unless otherwise specified. 7.5.2.5 (Mod) Except for clad or weld overlaid construction, gasketed tube-sheets shall be provided with 3 mm additional thickness to provide a future machining allowance on all gasket contact seating surfaces (including the pass partition). The additional base material thickness shall not be used in the MAWP calculation. 7.5.2.7 (New) Regardless of the pressure design code that is applied, the tube sheet thickness shall not be less than that required by TEMA clause R-7.11, unless otherwise approved by Purchaser. 7.5.2.8 (New) Fixed tube-sheets for removable bundles with bonnet fixed heads shall be through-bolted, unless otherwise approved by Purchaser. The holes shall not be threaded. 7.5.2.9 (New) The welded connections between a tube sheet and the adjacent cylinder/shell body shall be in accordance with ASME Code Figure UW-13.3, Type (a) (b) or (c) or equivalent configurations in other design code. Figure UW-13.2 Type (a), (b), (c), (i), (j), (k), or equivalent, may only be used in non-cyclic service and leak class 3 where the design pressure is less than 60 barg and the design temperature is less than 300 °C. 7.5.2.10 (New) Tube-sheets with cladding (or weld overlay) shall meet the following requirements:

The cladding shall be integrally and continuously bonded to the base material. Brazing shall not be used to bond the cladding to the tube-sheet.

Cladded and weld overlaid tube-sheets shall be 100% ultrasonically tested to check the integrity of the bonding in accordance with ASTM A 578 to guarantee no dis-bonding.




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7.5.2.11 (New) Heat exchangers which are of the multi-pass type on the tube side shall have tube sheets with 5 mm grooves on the channel side for accommodating the partition gasket. The bottom of the groove shall be flush with the contact surface of the peripheral gasket of the tube sheet. 7.5.2.12 (New)Minimum thickness of the tube sheet shall be the outside diameter of the tube plus the corrosion allowance of the tube side and shell side of the exchanger.

7.5.3 Baffles and support plates

7.5.3.1 (Mod.) For exchanger with titanium tubes, baffle/support plates thickness shall be in accordance with TEMA; however, the minimum thickness shall not be less than 5 mm. 7.5.3.4 (New) Baffle distance and type shall be as per project data sheet. In case of no data in data sheet; The unsupported tube span shall not exceed 80% of the value indicated in TEMA Table RCB-4.52, except that it shall not exceed 60% in the following cases:

1. Titanium tubes and applications with similar tube wall thickness and elastic modulus combinations.

2. Tubes in kettle-type re-boilers, evaporators, and steam generators. As a minimum the baffle system shall be designed and constructed according to TEMA code "R" but has also to respect the imposition of relevant code. 7.5.3.5 (New) When a full support baffle at the tangent line of U-bends is specified on the data sheet, the full support shall have cut-outs to allow fluid circulation through the U-bend area (i.e. the support shall be cut above/below the top/bottom tube row). 7.5.3.6 (New) A full support baffle shall be provided at the shell inlet/exit nozzles for TEMA shell types "H", "G", and “X” and at the central nozzle for TEMA shell type "J". The baffle shall be located at the nozzle center-line. 7.5.3.7 (New) Floating heads in shells with removable shell covers shall be supported by a doughnut baffle with a thickness that is 3 mm larger than the tube support baffles. 7.5.3.8 (New) Standard tube holes in all transverse baffle and full support plates shall have a diameter 0.4 mm over the outside diameter of the tubes. 7.5.3.9 (New) Other types of supports such as wires, bands, strip baffles, etc., require approval of Purchaser. 7.5.3.10 (New) The free end of each tie rod shall be fitted with double nuts. The nuts shall be tack-welded together. 7.5.3.11 (New) Baffle shall not be placed on circumferential shell weld seam.




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7.5.4 Impingement protection

7.5.4.1 (Mod.) Impingement protection shall be provided when required by TEMA paragraph RCB-4.6 or when specified on the data sheet. Heat exchangers with vapor or steam (superheated, saturated or wet) in the shell side shall always have impingement protection. Impingement plates located in the necks of nozzles are not acceptable. 7.5.4.6 (Mod.) Perforated impingement plate shall not be used, unless otherwise specified in project data sheet or approved by Purchaser. 7.5.4.7 (Mod.) a) Where an impingement plate is specified with nozzle diameters of DN 400 (16”) or higher, three (3) tie rods/spacers shall be used for support. 7.5.4.7 (New) g) TEMA RGP RCB 4.62 shall be taken into account for design of impingement plates. 7.5.4.8 (New) A 10 mm diameter drain hole shall be provided in impingement plates that are welded to the shell if the plate prevents complete draining of the shell contents. 7.5.4.9 (New) Where a full or partial circumferential distributor belt is specified at the inlet, the distributor belt shall be attached to the OD of the shell with the inlet nozzle mounted on the distributor. The nozzle shall be located such that flow impinges on the shell OD and is diverted to a cut-out window in the shell for bundle entrance. The velocity in the annular space between the ID of the distributor and the OD of the shell shall not exceed the velocity in the nozzle. 7.5.4.10 (New) Except on fixed tube sheet exchangers and exchangers with vapour belt sleeves, impingement plates may be attached to the tube bundle.

7.5.5 Bypass sealing devices

7.5.5.1 (Mod.) Bypass sealing devices (such as flat seal strips, dummy tubes, or tie rods) shall be provided for all shell and tube exchangers that are not in isothermal condensing or boiling service on the shell side, as per project data sheet. Bypass sealing devices shall be located in the peripheral bypass lanes and in the bypass lanes between tube passes when pass partition lanes are not parallel to the baffle cut, whenever the width of the bypass lane exceeds twice the clearance between tubes. Bypass sealing devices shall be of equivalent material to the baffles. The number of seals in each bypass lane shall be as per following, unless the data sheet specifies otherwise:

1. When the distance between baffle-cut edges is six tube pitches or less, two seals shall be provided.

2. When the distance between baffle-cut edges exceeds six tube pitches, multiple seals shall be provided every four to six tube pitches between the baffle cuts.

3. The first and last seals shall be placed at one tube pitch or 32 mm, whichever is smaller, from the baffle cut line.




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4. For pull-through bundles, use three pairs of seal strips when the ratio of the baffle spacing to the shell diameter is one-third or less. With a larger ratio, a minimum of one pair of seal strips is required.

Sealing devices may be seal strips, tie rods with spacers, dummy tubes or combinations of these. 7.5.5.5 (Mod.) The nominal thickness of seal strips shall be as follows:

1. for removable bundles; the nominal baffle thickness or 6 mm, whichever is greater

2. for fixed tube-sheet exchangers; the nominal baffle thickness or 6 mm (1/4 in), whichever is less.

7.5.5.9 (New) Sealing devices shall normally be continuously welded or bolted to the stationary tube-sheet. Tubesheet materials that are non-weldable or that require post weld heat treatment shall have the sealing devices attached by bolts or studs. When the baffle cut is parallel to the center-line of the inlet and/or outlet nozzle, peripheral seal strips shall not be extended through the inlet and outlet baffle spaces. In this case, seal strips shall be welded to the first and last baffles.

7.5.6 Bundle skid bars

7.5.6.1 (Mod.) In heat exchanger with refractory surface inside the shell using continuous sliding bars are prohibited. Special sliding system element shall be developed in design for attaching to the bundle. 7.5.6.6 (New) Threaded holes in the tube sheet shall be provided for the installation of pulling eyes. Eyebolts quantities and diameter shall be calculated and supplied loose by Supplier. 7.5.6.7 (New) If for a removable bundle tongue and groove gasket faces are used (subject to Purchaser approval), Supplier shall provide guide studs and guide holes on matching shell flange and tube sheet. The same guides are required on removable covers and channels with a gasket face other than raised face.

7.5.7 Tube-to-tube-sheet joint

7.5.7.1 (Mod.) Strength weld shall be applied for tube to tube sheet joints as per section 9.5.6 of this specification, unless otherwise specified in data sheet/technical specification. 7.5.7.3 (Mod.) Grooves shall not be used for tube to tube sheet expansion especially for hydrogen services, unless otherwise approved by purchaser before order placement.




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7.6 NOZZLES AND OTHER CONNECTIONS

7.6.1 (Mod.) All connections shall be flanged with through bolting as per design code. Flanges shall be welding neck, raised face with a surface finish of Ra 3.2 to 6.3 μm, unless otherwise specified. Threaded and socket-welded connections shall not be used. Butt-weld ends, ring joint flanges, or proprietary designs (e.g. self-energizing seal ring and hub with clamped connectors) may only be used when specified or approved by the Purchaser. 7.6.2 (Mod.) Welded connection shall be beveled. Details shall be specified according to piping connection thickness. 7.6.4 (Mod.) Only forged weld-neck or long weld-neck flanges shall be used. Use of slip-on and lap joint flange types shall be approved by Purchaser. 7.6.5 (New) f) Ammonia services. g) Lethal and Toxic services 7.6.6 (Mod.) Insulation thickness shall be specified/considered as per project data sheet. 7.6.9 / 7.6.10 (Mod.) For nozzle load calculation refer to 10000-M50-211. 7.6.11 (Mod.) Reinforcements pads shall not be used for following service conditions and self- reinforced nozzle shall be used.

working in severe temperature gradient service or creep temperature range working in fatigue condition with wall thickness greater than 30 mm in Hydrogen services or ammonia services in lethal services

7.6.12 (New) Nozzle necks shall be seamless pipe. For nozzle necks greater than DN 600 (NPS 24), welded construction is acceptable provided that the longitudinal seam is subjected to 100% radiography. 7.6.13 (New) Vents and drains with blind flanges shall be provided at the highest and lowest points on both channel and shell side, if complete venting and draining cannot be accomplished through the inlet or outlet nozzles.

7.7 FLANGED EXTERNAL GIRTH JOINTS

7.7.4 (Mod.) The clearance between flanges or flange and tube-sheet after assembly shall not be less than 4.8 mm at the periphery of the flanged joint. 7.7.6 (Mod.) Hydraulic bolt tensioning shall be applied for bolt sizes more than 1 ½” in




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all services and rating. 7.7.15 (Mod.) Except for clad or weld overlaid construction, external girth flanges shall be provided with 3 mm additional thickness to provide a future machining allowance on the gasket contact seating surface. The additional thickness shall not be used in strength calculation. 7.7.17 (New) Clad or weld overlaid ferritic steel flanges shall not be used with solid alloy shells or channels, and solid alloy flanges shall not be used on clad or weld overlaid ferritic shells or channels (i.e. dis-similar metal welds between flanges or integral tubesheets and the cylinders to which they are welded is not permitted), unless otherwise approved of the Purchaser. 7.7.18 (New) All bolts shall straddle both the horizontal and vertical centerlines, unless otherwise specified by Purchaser. The number of bolts shall be a multiple of four(4). 7.7.19 (New) The gasket pass partition rib area shall be added to the peripheral gasket area for the purposes of determining the required bolt loads (e.g. Wm1 and Wm2 in ASME). 7.7.20 (Mod.) Where serrated or grooved metal gaskets with graphite, PTFE, or other non-asbestos facing are used, the values of m and y, as defined in the ASME code, shall not be less than 3.75 and 52.4 MPa; respectively. 7.7.21 (New) Application of the ASME Code flange rigidity index calculation, based on design pressure shall be utilized for all external girth flanges and floating head flanges. The rigidity index shall not exceed 1.0; except for hydrogen services and for flanges on shells with less than 610 mm (24 in) nominal diameter and design pressures less than 27.6 bars, that the rigidity index shall not exceed 0.7.

7.8 GIRTH FLANGE JOINT SUPPLEMENTARY DESIGN REQUIREMENT

7.8.1 (Mod.) The requirement contained in this section shall be applied for Body thickness is ≥ 40 mm or Design pressure is ≥ 100 Bars or Leak class 1 or Carbon steel or low alloy steel in hydrogen or Ammonia services or toxic service or Pressure or temperature induced cyclic service or Heat exchangers which operate in the creep range of the materials of

construction.




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7.9 EXPANSION JOINTS

7.9.1 (Mod.) A thin-wall bellows expansion joint on the shell in hydrogen service and very toxic service is not allowed. It is the Supplier’s responsibility to determine the need for expansion joint in the shell. 7.9.2 (Mod.) (c) Expansion joint design based on mean metal temperatures shall meet the requirements of the pressure design code. The life cycle shall not be less than 10,000/1000 normal operating for calculation by EJMA/design code, respectively. Expansion joint shall be designed to withstand against twice of the calculated displacement from thermal expansion. 7.9.2 (Mod.) (d) 100% RT shall be applied for expansion joint longitudinal seam. Expansion joints shall be designed as solid mono-wall metallic joints made of stainless steel or higher alloys if required due to material selection or specified by purchaser. Expansion joints shall be provided with an internal sleeve to reduce pressure drop and to prevent by-passing. Multi wall expansions joint shall not be used.

7.10 GASKETS

7.10.1 (Mod.) The gasket type and gasket materials for external girth flanges and floating head flanges shall be as per data sheet and technical specification. Acceptable gasket types for hydrocarbon and steam services are spiral wound graphite-filled, and serrated or grooved metal graphite-covered (also known as kammprofile). For hydrogen service, gaskets shall be spiral wound graphite-filled or serrated metal graphite-covered type. Solid metal gaskets shall not be used for girth flanges, except where self-energizing sealing rings with clamp connectors, welded lip-seal type, or welded diaphragm type gaskets, if specified in data sheet. 7.10.2 (Mod.) f) Shell diameter greater than 1000 mm. 7.10.2 (New) g) without purchaser approval h) toxic and lethal services

7.11 HANDLING DEVICES

7.11.1 (Mod.) Heat exchanger and all of its attachments shall be designed for external load cases as per “Pressurized Static Equipment” document No 10000-M50-211. All external attachments material grade shall be same as heat exchanger body material grade.




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7.11.4 (Mod.) All vertical exchangers shall be provided with lifting devices for the entire exchanger and a tailing lug. The lifting device shall be located such that the exchanger weight is not carried through bolted joints and shall be above the center of gravity of the exchanger. 7.11.5 (New) Exchangers with removable bundles shall have two clamps welded to the shell flange to facilitate a bundle puller if diameter fixed tubesheet (TEMA Type B) or shell diameter were greater than 1000 mm. The clamps shall be 150 mm x 150 mm and have a thickness suitable for a bundle pulling load based on 150% of the bundle mass. The clamps shall be located in each of the two lower quadrants, with a center to center distance of approx. 460 mm. If other provisions are required they shall be stated in the project specification. 7.11.6 (New) A minimum of three (3) jack bolts shall be provided in girth flanges and tube sheets.

7.12 REQUIREMENTS FOR HYDROGEN SERVICE

7.12.3 (Mod.) If the purchaser specifies that the tube side and/or shell side will be exposed to hydrogen service (even for carbon steel material); all requirement of hydrogen services stated in specification 10000-M50-211 and 10000-M50-187 shall be applied for both sides.

8 MATERIAL

8.1 GENERAL

8.1.4. (Mod.) Material shall be as per project technical specifications and data sheet. 8.1.6 (New) If the tube-sheet forms a flange or is directly welded to the shell it shall be supplied as a forging and not as plate material. 8.1.7 (New) Galvanized materials or zinc containing paints shall not be used in direct contact with exposed stainless steel or high nickel alloy pressure components. 8.1.8 (New) Dis-similar metal welds shall not be used for pressure boundary welds especially for hydrogen service, unless approved by the Purchaser. 8.1.9 (New) Materials used for the fabrication of pressure retaining components shall be traceable to suppliers which have a quality management system which is approved by the International Standards Organization, ISO 9001.

8.3 GASKETS

8.3.3 (Mod.) Unless otherwise specified, material for spiral wound, serrated metal, gaskets shall be 304 or 316 grade stainless steel. Low carbon grades of 304L or 316L




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stainless steel shall be used when gaskets are made with welds. Where the gasket contact surface of the flange or tubesheet is in higher alloy, the gasket material shall match the chemical composition of that alloy. 8.3.7 (New) For gaskets on the cooling water side of exchangers with stainless steel flanges or tubesheets, graphite and ‘full density’ PTFE shall not be used. Expanded PTFE (e.g. Gore-Tex type), can be used. Only PTFE that contains no free fluoride ions (F-) is allowed in contact with the stainless steel.

8.4 TUBES

8.4.1 (Mod.) Copper and copper alloys shall not be used, unless otherwise specified in project data sheet. 8.4.2 (Mod.) All tubes shall be tested by a non-destructive electric method (eddy current) as per applicable standard. Heat treated tubes shall be tested after heat treatment. 8.4.3 (New) For calibration of testing equipment for repeated testing of tubes; Supplier shall provide a minimum 2 m long calibration tube (2 X 1 meter). The tube shall be marked with:

Plant ID Buyer Tag nr of the equipment Material, including heat number Tube dimensions (OD x Wall thickness)

The calibration tube shall be delivered, accompanied with a material certificate, together with the original heat exchanger.

9 FABRICATION

9.4 TUBE

9.4.2 (Mod.) Defective tubes shall be replaced with new tubes, where bundle type and access permits. Where tubes are not practically accessible for replacement, as defined in TEMA, the Plugging Procedure shall be approved by the Purchaser. Where plugs are welded, the relevant welding procedure shall be approved by the Purchaser.

9.9 WELDING

9.5.1 (Mod.) All welding, welding procedures and qualification testing, and welder performance testing shall be as per 10000-M50-211 or applicable project welding specification. Welding procedures and qualifications shall be approved by the Purchaser prior to the start of fabrication. 9.5.2 (Mod.) All welds for pressure parts shall be full penetration welds.




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9.5.6 (Mod.) tube to tube sheet welding fabrication and detail shall be applied for tube to tube sheet welding as per heat exchanger leakage class:

Leakage Class 1

Leakage Class 2

Leakage Class 3

Orbital automatic welding of tube to tube sheet X X Tube to tube sheet welding in two layers X X Weld thickness of tube to tube sheet 100% X X X Strength welding and hydraulic expansion (Expansion is not applicable for Urea High Pressure equipment)

X

Strength welding and rolling X X Rolling without welding X

Accepted tube to tube sheet connections are according EN 1708-1 or ASME Sec VIII Div 1 Fig UW 20.1, whichever is applicable. UW20.1 (a) and Sketch 7.1.2 (EN 1708-1) are only acceptable for titanium tubes exchangers and high pressure urea equipment (when leak detection system shall be applied) and heat exchangers in leak class 3. Sketch 7.1.1(EN 1708-1) is only applicable for leak class 3. Deviations may only be accepted after approval of the Purchaser. Tube to tube sheet welds shall be minimum two (2) weld passes using the orbital automatic GTAW process, unless otherwise approved by Purchaser. The length of the combined weld legs measured parallel to the longitudinal axis of the tube at its outside diameter shall be at least 1.4 times the nominal thickness of the tube.

9.10 HEAT TREATMENT

9.6.2 (Mod.) Unless otherwise specified, the following tube materials shall be subject to heat treatment after bending:

Heat treatment of the bend area for carbon steel and low alloy steel U-tubes having a mean radius smaller than 5 times the nominal tube OD

Heat treatment of the bend area for all carbon steel and low alloy steel U-bends when hydrogen service is specified.

Solution annealing for 304 and 316 grade stainless steel U-bends having a mean radius smaller than 5 times the nominal tube OD. 304 and 316 grade stainless steel tubes shall be supplied as low carbon grade (or dual certified as low carbon grade) when solution annealing of the U-bends will be conducted;

For 12 and 17 Cr, duplex stainless steel, and nickel alloys, heat treatment of U-tubes




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shall only be applied when approved by the Purchaser. In all cases, the method and extent of the heat treatment of U-tubes shall be approved by Purchaser. Special consideration shall be given to the transition zone during heat treatment as it could induce embrittlement or susceptibility to stress corrosion in the transition zones between the straight legs of the U-tube and the U-bend. 9.6.10 (Mod.) PWHT for weld overlaid parts shall be as per design code for base metal when buttering and at least 1st pass of weld overlay have been performed. Minimum 2 layer of weld overlay shall be applied after PWHT. 9.6.14 (New) Post-weld heat treatment shall conform to design code and 10000-M50-187 when applicable. 9.6.15 (New) The faces of all flanges including girth joints shall be checked / re machined after welding and / or heat treatment. 9.6.16 (New) For the stress relieving of the complete fixed tube sheet heat exchangers; the parameters shall be adapted to avoid differences of any metal temperature larger than 30 °C. Otherwise for mentioned condition and other critical PWHT conditions Supplier shall submit a stress analysis report (FEA) for Purchaser review and approval. 9.6.17 (New) Channels and bonnets with welded partition plates shall be stress relieved. The procedure for stainless steel shall be agreed upon with the Purchaser.

9.11 DIMENSIONAL TOLERANCES

All tolerances shall be in accordance to 10000-M50-211, “Pressurized Static Equipment”.

9.9 TUBE HOLES

9.9.2. (Mod.) If austenitic stainless steel, duplex stainless steel, titanium and nickel-alloy tubes are specified, the tube holes shall be machined in accordance with Special Close Fit in TEMA standard, except for high pressure urea equipment. For high pressure urea equipment and when leak detection is mandatory, expansion of the tubes in the tube sheet is therefore not allowed and The minimum difference between the outer diameter of the tubes and the diameter of the tube sheet holes shall be 0.2 mm at closest tolerance.

9.10 TUBE TO TUBE SHEET JOINTS

(New) An expansion procedure shall be submitted for approval. Expansion shall be performed after welding. Exceptions can be accepted, only after approval of the Purchaser.




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9.10.1 (Mod.) Mechanical expansion by roller shall be performed as per below guidelines. Tube wall reduction is defined as follows:

C

dDtT

2

)()( 100

Where: T is tube ID after expansion t is tube ID before expansion D is diameter of tube hole d is tube OD

C is 2)( td

The amount of tube wall reduction to achieve 100% bond shall be:

1 to 3% of original tube wall thickness for light expansion (carbon and low alloy steel)

1 to 3% of original tube wall thickness for light expansion (stainless and high alloy steel)

4 to 6% of original tube wall thickness for strength expansion (carbon and low alloy steel)

6 to 8% of original tube wall thickness for strength expansion (stainless and high alloy steel)

4 or 5% of original tube wall thickness for expansion on non-ferrous tubes A minimum of 2% of the tubes per tube bundle, with a minimum of five (5) tubes, shall be randomly checked for conformance to this requirement by use of calibrated micrometer. A report of expansion check shall be prepared for the inspector’s review and acceptance. This report shall be part of the final documentation. Data to be recorded:

Tube sheet hole diameter Tube OD Tube thickness Tube ID before expansion Tube ID after expansion Tube wall reduction % from calculations

9.10.8 (New) If Hydraulic expansion was specified in project specification or if it is required by Supplier design practice, it shall be supported by calculation note. The hydraulic pressure shall be calculated taken into account measured dimensions such as tubesheet hole diameter, tube ID, tube OD, wall thickness and material properties such as tube yield strength, tube sheet yield strength, Young and Poisson modules.




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Calculations shall be submitted for Purchaser review and approval.

10 INSPECTION AND TESTING

10.1 QUALITY CONTROL

10.1.1 (Mod.) NDE shall be performed as per 10000-M50-211, “Pressurized Static Equipment” and this specification; in addition to API 660 requirement. 10.1.2 (Mod.) Set on nozzles and connections are not allowed. 10.1.6 (a) (Mod.) Refer to additional requirements as specified in 10000-M50-211 and 10000-M50-187. 10.1.6 (c) (Mod.) In Hydrogen Services, hardness shall be limited to 200 HB (205 HV) for carbon steel and 225 HB (240 HV) for Cr-Mo steel. 10.1.6 (d) / (e) (Mod.) Hardness test shall be performed as per Specification for “Post Weld Heat Treatment” Document No. 10000-M50-187. Hardness test shall be performed on the base metal, weld metal and heat-affected zone on both sides of pressure-retaining welds. 10.1.14 (Mod.) Ferrite test shall be performed on austenitic stainless steel pressure retaining welds. 10.1.18 (a) (Mod) Refer to section 7.2.2 of this specification. 10.1.19 (New) After expanding of tubes, 100% of tube end welds shall be examined by the liquid-penetrant method. Any repairs to tube end welds shall be re-examined by the same method. 10.1.20 (New) All NDE shall be performed before and after PWHT, unless otherwise approved by purchaser. 10.1.21 (New) Following inspection shall be performed as per leakage class;

Leakage Class 1

Leakage Class 2

Leakage Class 3

100 % Dye Penetrant testing of tube to tube sheet weld per weld layer (*)

X

100% Dye Penetrant testing final welding tube to tube sheet

X X X

100% volume NDT of tube to tube sheet welds (only applicable for HP Urea applications and Internal bore welding)

X




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Mock-up of tube to tube sheet connection (**,***) X Air bubble test of tube to tube sheet weld before rolling / hydraulic expansion

X

Dye Penetrant testing after hydraulic pressure test X X Hydraulic testing of both compartments X X X Push/pull out test X

* Exception is accepted in case of continuous orbital welding ** Exception can be made when a mock up test is available with same materials, same dimensions, and same weld parameters. When a mock up test is older than 1 year is performed, a new mock up test is required. Mock up testing shall be according EN15614-8. The qualification shall be stamped and signed by a Notified Body/ASME Inspectorate. *** Mock up shall simulate actual welding condition. In case of tube in duplex, Super duplex material, tube sheet thickness for mock up shall be same as actual tube sheet. A tensile pull-test shall be performed on the qualification test coupon. A minimum of three (3) tests shall be performed. Loads for Push-out and pull-out test shall be equal to calculated loads on tube to tube sheet weld. Push-out and pull-out test shall be performed and this test will not waive radiography test on mock up.

10.2 PRESSURE TESTING

10.2.4 (Mod.) Hydrostatic test for heat exchanger shall prove integrity design and construction of each side of exchanger. Shell side and tube side shall be tested separately. In case of different in test pressures, tube side and shell side shall also be tested simultaneously. 10.2.5 / 10.3.6 (Mod.) Water quality shall be as per 10000-M50-211. 10.2.7 (Mod.) Both side of heat exchanger shall be purged and dried as per 10000-M50-211, after hydrostatic test. 10.2.14 (New) For floating head heat exchangers; shell side shall be tested with the bundle in place and a test ring as a seal between the floating tube sheet and the shell. This pressure test shall be performed without channel. The tube side pressure test shall be performed with channel and floating head cover installed. After total assembly of the heat exchanger the shell side pressure test shall be repeated. 10.2.15 (New) The equipment required for the pressure tests shall be supplied by the manufacturer and property of the test equipment shall be transferred to the Purchaser. Where several exchangers can be tested by means of the same ring, one test ring shall be provided. If identical shells are to be stacked, one test ring per shell shall be supplied.




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11 PREPARATION FOR SHIPMENT

11.1 PROTECTION

11.1.7 (Mod.) Surface protection shall be as per 10000-Y50-042.

12 SUPPLEMENTAL REQUIREMENTS

12.1 GENERAL

(Mod.) The supplemental requirements of section 12 shall be applied when; Body thickness is ≥ 40 mm or Design pressure is ≥ 100 Bars or Leak class 1 or Carbon steel or low alloy steel in hydrogen or Ammonia services or toxic service or Pressure or temperature induced cyclic service or Heat exchangers which operate in the creep range of the materials of

construction.




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APPENDIX 1 – LEAK CLASS 1

Heat Exchangers in leak class 1

App 1.1 - Urea service Pool condenser HP carbamate condenser Hp stripper HP scrubber

App 1.2 - Ammonia service Waste Heat Boiler after Secondary Reformer Waste Heat Boiler after Synthesis reactor HP exchangers in the Synthesis HP BFW exchangers Steam Heaters in the Cold Box loop

App 1.3 - Nitric Acid High temperature Waste Heat Boilers Process gas Condensers Tail gas super heater

App 1.4 - Ammonium Nitrate Solution Nitric Acid Heater Steam generator

App 1.5 - Hydrogen Services

All application




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APPENDIX 2 – LEAK CLASS 3

Heat Exchangers in leak class 3 App 2.1 - Urea service

Utility services LP Cooling water coolers Oil coolers

App 2.2 -Ammonia service Utility services LP Cooling water coolers Oil coolers

App 2.3 -Nitric Acid Utility services LP Cooling water coolers Oil coolers

App 2.4 -Ammonium Nitrate Solution Utility services LP Cooling water coolers Oil coolers

Documents

STD Spec for Shell and Tube Heat Exchangers