5578-E1-SP-ME-001_R0

ABU DHABI OIL REFINING COMPANY PROJECT SPECIFICATION TAKREER

PROJECT No. 5578

AGREEMENT NO. 09-5578-E-1

SHELL AND TUBE HEAT EXCHANGER DESIGN CRITERIA

RUWAIS REFINERY EXPANSION PROJECT PROJECT DOC. NO.: 5578-E1-SP-ME-001 Rev. 0

This document / drawing including all information was developed and prepared by SKEC for the project and remains the property of TAKREER. All SKEC proprietary information or underlying intellectual property utilized in the creation of the design or information contained herein shall remain the property of SKEC.

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This page is a record of all revisions of this document. All previous issues are hereby superseded and are to be destroyed.

REV DATE REASON FOR ISSUE BY CHKD REVD APPR`D COMPANY

0 13 May 10 Issue for Construction DHL HJL WYC ESJ

B 23 Mar 10 Issue for Approval DHL HJL WYC ESJ

A 15 Dec 09 For Comment/Review BCH HJL WYC ESJ

SIGNED (Initials) DHL HJL WYC ESJ

NOTES: (a) By a vertical line in the right-hand margin against the revised text.

(b) By a triangle symbol for graphics, the revision number being denoted within the symbol.

Revision symbols are positioned adjacent to the revision.

(c) CHKD = Checked by, REVD = Reviewed by, APPR`D = Approved by


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PARAGRAPHS REVISED THIS ISSUE

Para. No. Para. No. Para. No. Para. No.

NOTES:

(a) This specification has been made by merging TAKREER Design General Specification for Shell and tube heat exchanger design criteria (DGS-ME-001) and its amendment (5578-AMD-ME-001) and by adding the contract requirements clarified during the bidding stage.


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TABLE OF CONTENTS

1. GENERAL .................................................................................................................................. 5

1.1 INTRODUCTION ............................................................................................................ 5

1.2 PURPOSE ......................................................................................................................... 5

1.3 DEFINITIONS ................................................................................................................. 5

1.4 EXCEPTIONS .................................................................................................................. 6

2. CODES AND STANDARDS ..................................................................................................... 6

3. REFERENCE DOCUMENTS .................................................................................................... 6

4. DOCUMENT PRECEDENCE ................................................................................................... 7

5. SPECIFICATION DEVIATION/CONCESSION CONTROL .................................................. 8

6. QUALITY ASSURANCE/QUALITY CONTROL ................................................................... 8

7. DOCUMENTATION .................................................................................................................. 8

8. SUBCONTRACTORS/VENDORS ............................................................................................ 8

9. HANDLING ................................................................................................................................ 8

10. DESIGN ...................................................................................................................................... 8

10.1 GENERAL REQUIREMENTS ........................................................................................ 8

10.2 TECHNICAL REQUIREMENTS .................................................................................. 13

11. MATERIALS .......................................................................................................................... 256

12. FABRICATION ........................................................................................................................ 26

13. TESTING .................................................................................................................................. 26


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1. GENERAL

1.1. INTRODUCTION This Specification establishes the criteria for the thermal design of standard TEMA type Shell and Tube Heat Exchangers for the PROJECT. It also defines the minimum process and mechanical data required for thermal and hydraulic design and completion of Heat Exchanger Data Sheets (hereinafter referred to as Data Sheets).

1.2. PURPOSE The purpose of this specification is to ensure consistency in selection and design of TEMA type shell and tube heat exchangers for the Project.

1.3. DEFINITIONS For the purpose of the specification, the following definitions shall apply:

GENERAL DEFINITIONS:

COMPANY shall be defined as ABU DHABI OIL REFINING COMPANY (TAKREER)

CONTRACTOR shall be defined as the organization to which TAKREER award the Engineering, Procurement and Construction (EPC) phase.

MANUFACTURER/VENDOR shall be defined as the supplier of equipment and support services for a particular piece of equipment/package.

SUB-CONTRACTOR shall be defined as any person or persons, firm, partnership, corporation or combination thereof engaged by CONTRACTOR (not being an employee of CONTRACTOR) for supplying services to CONTRACTOR for the performance of services.

SUB-VENDOR shall be defined as any supplier of equipment and support services for a particular piece of equipment/package to a VENDOR.

CONCESSION REQUEST A deviation requested by the SUBCONTRACTOR or VENDOR, usually after receiving the contract package or purchase order. Often, it refers to an authorization to use, repair, recondition, reclaim, or release materials, components or equipment already in progress or completely manufactured, but which does not meet or comply with COMPANY requirements. A CONCESSION REQUEST is subject to COMPANY approval.

SHALL Denotes mandatory action or requirement.

SHOULD Denotes an action or requirement which is not mandatory but which is strongly recommended.


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DOCUMENT Any form, letter, facsimile, contract, specification, requisition, drawing, or record of any kind required to transmit information from one party to another. It also includes computer generated drawings, lists, charts, etc. and other data used to form a permanent record of the Project progress

FEED Front End Engineering Design.

1.4. EXCEPTIONS This specification does not apply to design of Double Pipe Heat Exchangers, Plate Heat Exchangers, Water Cooled Surface Condensers, and Brazed Aluminum Fin Heat Exchangers. For other special applications only part of this specification may be relevant, subject to mutual agreement between VENDOR / MANUFACTURER and COMPANY /CONTRACTOR.

2. CODES AND STANDARDS

It shall be the VENDOR'S responsibility to be, or to become, knowledgeable of the requirements of the referenced Codes and Standards.

The following Codes and Standards, to the extent specified herein, form a part of this specification.

TEMA Tubular Exchanger Manufacturers Association Standards, Ninth Edition 2007.

API660 Shell & Tube Heat Exchangers for General Refinery Service, Eighth Edition 2007.

WRC Bulletin 107 Local stresses in spherical and cylindrical shells due to external loadings.

WRC Bulletin 297 Local stresses in spherical and cylindrical shells due to external loadings (Supplement to WRC Bulletin No 107).

International Organization for Standardization (ISO)

ISO 9001 - 2000 Quality Management System Requirements

ISO 9004 - 2000 Quality Management Guidelines for Performance Improvement System

ISO 19011 Guide for Quality / Environmental Management System Auditing.


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3. REFERENCE DOCUMENTS

The following reference documents, to the extent specified herein, form a part of this specification. When an edition date is not indicated for a document, the latest edition in force at the time of VENDORS/CONTRACTORS proposal submittal shall apply.

PROJECT SPECIFICATIONS Document No. Document Title

5578-E1-SP-MU-013 Criticality Rating System

5578-E1-SP-MU-014 Minimum Shop Inspection and Certification Requirements 5578-E1-SP-ME-002 Shell and Tube Heat Exchangers 5578-E1-SP-PU-101 Basic Engineering Design Data

STANDARD DRAWINGS Document No. Document Title

5578-E1-STD-MD-B-012 Equipment Support Saddles up to 3000mm Diameter 5578-E1-STD-MD-B-020 Equipment Nozzles

5578-E1-STD-MD-B-060 Brackets for Standard Vertical Reboilers, Nominal Diameter 350 up to & including 1100mm

5578-E1-STD-MD-B-061 Support Saddles for Stacked Units up to 750mm Diameter

5578-E1-STD-MD-B-062 Support Saddles for Stacked Units 751mm to 1600mm Diameter

5578-E1-STD-MD-B-063 Support Saddles for Stacked Units

4. DOCUMENT PRECEDENCE

The VENDOR shall notify the CONTRACTOR of any apparent conflict between this specification, the related Data Sheets, the Codes and Standards and any other specifications noted herein. Resolution and/or interpretation precedence shall be obtained from the CONTRACTOR in writing before proceeding with the design/manufacture.

In case of conflict, the order of precedence for documentation is:

a. Data sheets


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b. Specifications

c. Codes and standards

d. Standard drawings

5. SPECIFICATION DEVIATION/CONCESSION CONTROL

Any technical deviations to the Purchase Order and its attachments including, but not limited to, the Data Sheets and Narrative Specifications shall be sought by the VENDOR only through CONCESSION REQUEST format. CONCESSION REQUESTS require CONTRACTORS and COMPANYS review/approval, prior to the proposed technical changes being implemented. Technical changes implemented prior to COMPANY approval are subject to rejection.

6. QUALITY ASSURANCE/QUALITY CONTROL

The Criticality Rating (CR) System outlined in Project Specification 5578-E1-SP-MU-013 shall be used by CONTRACTOR or CONTRACTORS designee to develop the design checking levels and minimum requirements for shop inspection, testing and material certification given in Project Specification 5578-E1-SP-MU-014.

7. DOCUMENTATION

This section is not applicable to this specification.

8. SUBCONTRACTORS/VENDORS


9. HANDLING


10. DESIGN

10.1. GENERAL REQUIREMENTS 10.1.1. Definitions

Clean Service shall include services where the fouling resistance is less than or equal to 0.00041 m2hr/kcal (0.002 ft2hr/Btu) Fouling Service shall include all services not otherwise defined as clean service, or where mechanical cleaning is required.

10.1.2. Process Data


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In addition to heat duty, fluid identity, flow rates, design pressures and temperatures, operating pressures and temperatures, allowable pressure drops, material of construction and exchanger type and setting, the process data shall include, but not be limited to, the following:

10.1.2.1. Sensible Heat Transfer Service

a. Vapour and Gas

Density, thermal conductivity, specific heat and viscosity at two reference temperatures, molecular weight and hydrogen partial pressure.

b. Liquid

Density, thermal conductivity, specific heat and viscosity at two reference temperatures. For liquid streams having a high viscosity, a third viscosity data point at an intermediate temperature or viscosity/temperature correlation is desirable, except that when the viscous liquid is being cooled, the third data point should be at the average temperature of the opposing stream.

Physical properties of hydrocarbon streams shall be weighted to include the effect of miscible water, and shall be so specified.

Immiscible or free water shall be shown on the Data Sheet. Fluid properties shall not be weighted to include immiscible water.

10.1.2.2. Condensing Service

a. For isothermal condensing, physical property requirements shall be the same as for sensible heat transfer plus the liquid surface tension, bubble point / dew point, latent heat, quantity and molecular weight of non-condensable gas and quantity of steam when present. Data shall be supplied preferably at two pressures (i.e. the inlet pressure and the predicted outlet pressure). Vapour physical properties shall be weighted for the entire vapour phase mixture.

For cases where H2 content is more than 10 mol per cent, vapour mixture physical properties shall be given under three referenced temperatures. Latent heat for a steam / hydrocarbon mixture shall be for the hydrocarbon only.

b. For non-isothermal condensing services, the physical property requirements shall be the same as for sensible heat transfer plus the liquid surface tension. Heat release curves shall be provided at two pressures minimum (i.e. one data set at the inlet pressure, and one at the predicted outlet pressure) and shall specify duty and weight per cent vapour versus temperature. Fluid properties for both liquid and vapour phases shall be provided at each temperature point accordingly. Heat release curves and properties shall be weighted to take account of the effects of non-condensables and the presence of free water or


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steam.

c. When fluid entering an exchanger is a vapour mixture at its dew point temperature, liquid properties shall also be given at that temperature.

10.1.2.3. Boiling Service

a. Physical property requirements shall be the same as for sensible heat transfer plus liquid surface tension, mixture bubble point and dew point, critical pressure and temperature and latent heat.

b. The Process Engineer shall provide tables or curves showing vapor temperature and fraction vaporized at two constant reference pressures between bubble point and dew point, with three additional points between. The three additional points must be close to the operating range. For pure components or in cases with very narrow boiling ranges only vapor pressures at two temperatures need to be provided.

c. For non-linear heat release services, a plot with duty, molecular weight and weight percent vapor versus temperature shall be provided.

d. For kettle reboilers, the required entrainment ratio (kg liq/kg vapor) shall be provided, including steam purity for steam generators.

e. For thermosyphon reboilers complete piping geometry between the fractionating column and the reboiler must be analyzed, together with the available static head.

f. For thermosyphon reboilers, the heat release data mentioned in clauses b. & c. of this paragraph shall, as a minimum, be provided at the column liquid level pressure, and at a second higher pressure (e.g. column liquid pressure + 0.5kg/cm2).

10.1.2.4. Corrosion Allowance

a. For all exchanger parts, except tubes, the materials of construction and corrosion allowance shall be selected to give exchangers a design service life of 30 years, in accordance with Project Specifications. Corrosion allowance shall be specified on the Data Sheets.

b. Tubes shall have a design life of ten years, and where necessary to achieve this, corrosion allowance for tubes in high pressure service shall be specified.

10.1.2.5. Fouling

Fouling factors and cleaning requirements shall be specified on the Data Sheets.

10.1.2.6. Nozzle Sizes


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Where practical, the exchanger nozzles shall be designed to match the line sizes provided that the exchanger's thermal, vibration and hydraulic requirements are met, and that TEMA entrance and exit velocity criteria are met.

10.1.2.7. Excess Heat Transfer Surface

Any requirements for excess surface must be fully explained on the Data Sheet, with instruction on effect on flow, temperatures and pressure drops if these are to differ from those listed on the Data Sheets. It is insufficient to add notes such as provide 10 percent excess surface.

Over-design margins used in the sizing of heat exchangers shall be as specified on the equipment / process data sheets. Care should be taken to ensure that the correct margin is used and doubling up of design margins is avoided.

10.1.2.8. Design Temperature and Pressure

a. All parts of the tube bundle including floating head shall be designed for either full tube side internal pressure or full shell side external pressure, whichever condition is controlling. Differential pressure shall not be used as design basis unless specified.

b. In selecting design temperatures for multiple exchangers in series, consideration shall be given to the maximum or minimum temperature, on each side of each exchanger that results from either fouled or clean operation.

c. The differential between the inlet and outlet operating temperatures of a shell side fluid should not exceed 200C (392F) per shell.

d. The differential between the inlet and outlet operating temperatures of channels of multipass exchangers should not exceed 120C (248F) per exchanger.

e. For the determination of the design pressure on the low pressure side, the greater of the initial design pressure on the low pressure side or 77% of the design pressure on the high pressure side shall be taken. However, if it is economic to maintain the initial design pressure on the low pressure side by installing a relief device, this may be considered. The size of the relief device shall be determined based on a possible tube rupture. The size of the leak shall be taken twice the internal cross-sectional area of one tube.

f. For heat exchangers in series, individual shells of a unit may have different design temperatures for economy in material selection. Where this applies, measures shall be taken to prevent incorrect line-up of shells within the unit.

g. The effect of the temperature profile over a thick wall tubesheet not being linear shall be taken into account because this may have a large consequence on the mean metal temperature as well as on the temperature gradient and stresses within the tubesheet.


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h. Unless otherwise specified on Data Sheets/drawings, the design pressure shall be as follows:

MAXIMUM OPERATING PRESSURE DESIGN PRESSURE (kg/cm2 G): (kg/cm2 G):

Full or partial vacuum 1.05 external/5.3 internal 0 (Gauge) - 0.35 0.5 external/5.3 internal 0.36 - 3.6 5.3 3.61 - 17.2 Operating + 1.7 17.3 - 70.0 Operating + 10 % 70.0 - 140.0 Operating + 7.0 140.0- Up Operating + 5%

i. Both, Design Temperature (DT) and Minimum Design Metal Temperature (MDMT) shall be identified on Data Sheets.

10.1.2.9. Allowable Pressure Drop

Allowable pressure drop shown on the Data Sheet shall be for clean conditions.

10.1.3. Mechanical Data

The complete Data Sheets shall include the following information, as a minimum:

a. Process data (including heat release curves, when applicable).

b. Parameters defining exchangers thermal performance (i.e. heat transfer coefficients, calculated pressure drops, Mean Temperature Difference, etc.).

c. Definition of exchangers type and orientation.

d. Identification of any special design considerations.

e. Outline drawing, defining overall dimensions, required maintenance clearances, locations of vents, drains and any other non-process connections, process nozzles size, rating, location and projection, saddles location and projections, location and sizing of the anchor bolts, and flow direction.

f. Definition of internals, like baffle spacing or internal expansion joints.

g. Tube layout including as a minimum: number of tubes, tube diameter, outer tube limit (OTL), baffle cut, baffle orientation, sealing and sliding strips, tie rod location and size, definition of impingement protection (if required), and schematic identification of the shellside nozzle size.


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h. Identification of materials and corrosion allowances.

i. Identification of special services and NDE requirements.

j. Identification of PMI requirements.

10.2. TECHNICAL REQUIREMENTS 10.2.1. General Requirements

a. TEMA Class Selection

All shell and tube heat exchangers for this PROJECT shall be in accordance with TEMA class R.

b. The thermal design and rating shall be based on the design methods which have been proven in practice. In this respect, the design procedures and computer programs published by the Heat Transfer Research Institute (HTRI), and Heat Transfer and Fluid Flow Service (HTFS) are considered proven design methods. HTRI Methods are preferred.

10.2.2. Exchanger Type Selection

10.2.2.1. Front/Rear Head Selection

a. Type B front head shall be used for clean service and/or for design pressure above 30.0 kg/cm2(G). For fouling service and for design pressure less than or equal to 30.0 kg/cm2 (G), Type A front head shall be used.

b. Rear end head Type M should be used for fixed tubesheet designs. However, for heat exchangers with a Type A front end stationary head and an odd number of tube passes Type L shall be selected.

c. Rear end head Type S should be used for floating head type heat exchangers with a nominal shell diameter of more than DN 250. Alternative construction would need to be considered for diameters up to DN 250. Rear end head Type T shall be used for a kettle type heat exchanger with floating head.

d. Types P and N are not permitted.

e. High pressure or other design requirements may justify deviation from the guidelines shown.

10.2.2.2. Use of Fixed Tubesheet (non-removable bundle) Exchangers

a. Use of fixed tubesheet exchangers requires prior approval by the COMPANY.

b. Non-removable bundle exchangers may be used in clean shellside service where a shellside expansion joint is not required. The use of shellside expansion joints requires prior approval by the COMPANY.


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c. The differential expansion between shell and tubes of a fixed tubesheet exchanger shall be based on the controlling metal temperatures, either clean or one side fouled.

d. The maximum controlling differential temperature between the tube and shellside during operation, start-up, shutdown or steam-out shall be stated on the Data Sheet and used to determine the requirement for an expansion joint and tubesheet thickness on a fixed tubesheet heat exchanger. If design consideration result in expansion joint being required, a removable bundle type exchanger shall be selected.

10.2.2.3. Use of U-Tube Bundles

U-tube bundles shall be used only for the clean service on the tubeside as defined in paragraph 10.1.1. Other design considerations may govern, but require prior approval by the COMPANY.

10.2.2.4. Shell Selection

The single-pass shell, Type E, shall be selected for general duties, except as indicated below:

a. Where the shellside pressure drop is a restricting factor, the divided flow shell Type J or cross-flow shell Type X or double-split flow shell Type H, should be considered.

b. For horizontal shellside thermosyphon reboilers, Types G, H, J, or X should be selected.

c. The kettle type shell, Type K, should be selected for boiling where almost 100% vaporization (0-5% entrainment) or where a phase separation is required.

d. The use of TEMA Type F shells with removable bundles is discouraged unless there are considerable economic savings or design advantages. Limit shellside pressure drop to 0.49 kg/cm2 (7.0 psi) per shell and temperature differential between shell inlet and shell outlet to 140 (252).

10.2.2.5. Horizontal and Vertical Exchangers

a. Heat exchangers should be of the horizontal type: however, for process requirements or where cleaning and other maintenance will be infrequent or space requirements make it more attractive, the vertical arrangement may be considered.

b. For thermosyphon reboilers, vertical orientation is generally preferred to horizontal orientation. However, all aspects of design, operation, vibration, maintainability, and performance should be evaluated when making the selection.


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c. When horizontal arrangements are preferred, the stacking of exchangers should be considered to conserve space in the structure. Preferred stacking should be 2 (two) shells high.

10.2.3. Tube Bundle

10.2.3.1. Design Considerations

a. Maximum Size

Maximum sizes shall be as shown below. Larger sizes may be considered to realize economic or design advantages. Larger sizes must be approved by the COMPANY.

The maximum straight length for tubes shall be 7300 mm.

The maximum bundle diameter for removable bundle exchanger shall be 2100 mm.

The maximum removable bundle weight shall be 45000 kg.

b. Standard straight lengths for tubes shall be as follows:

Millimeters 2438 3048 3658 4877 6096 7315

(Feet) (8) (10) (12) (16) (20) (24)

c. The ratio of tube length to bundle outer diameter for removable bundles shall be less than 10:1.

d. The maximum tube length for vertical thermosyphon reboilers shall be 6096 mm (20 ft).

e. Selection of different tube lengths than above for U-tubes may be considered when economically justified.

f. Fixed tubesheet exchangers (when approved) may be designed with longer tube lengths than stated in clause b of this paragraph if by doing so results in a significant economic or technical advantage. This approach is acceptable since removal of the tube bundle for maintenance purposes is not required for fixed tubesheet construction. The maximum tube length for fixed tubesheet bundles shall be 18300 mm (60 ft).

10.2.3.2. Tube Diameters and Gauges

The following table specifies bare tube diameters and minimum permissible gauges (BWG):

Tube OD Carbon Steel And Low Alloys

Copper, Copper Alloys And High Alloys


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Tube OD Carbon Steel And Low Alloys

Copper, Copper Alloys And High Alloys

19.05 mm (0.75 in.)

(Min. Wall) 2.11 mm

(0.083 in.)

(Min. Wall) 1.65 mm

(0.065 in.) 25.4 mm

(1 in.) 2.77 mm

(0.109 in.) 2.11 mm

(0.083 in.) *31.75 mm (1.25 in.)

3.40 mm (0.134 in.)

2.77 mm (0.109 in.)

* Use of 31.75 mm OD tubes requires prior approval by COMPANY.

For materials not listed, tube wall thickness shall be selected following a review of applicable design factors (design pressure, tube diameter, corrosion characteristics, etc.) and current conventional / best practice.

15.875mm (5/8 inch) diameter tubes may be considered for Feed / Effluent heat exchangers in relatively clean applications (e.g. the so-called Texas Tower design in Platformer units). Tube wall thickness shall be as tabulated above for 19.05mm (3/4 inch) diameter tubes.

10.2.3.3. Tube Diameter, Pitch and Layout

The following table defines criteria for selection of tube diameter, pitch and layout:

Shellside service

Tubeside Fouling m2hr/kcal (ft2hr/Btu)

Min. Tube O.D.

mm (in.)

Pitch, mm (in.) and layout

Clean* Up to and including

0.0006 (0.003) 19.05 (0.75)

25.4 (1.0) 30o/45o/90o

Clean* Over

0.0006 (0.003) 25.4 (1) 31.75 (1.25) 30o/45o/90o

Fouling* Up to and including

0.0006 (0.003) 19.05 (0.75) 25.4 (1) 45o/90o

Fouling* Over 0.0006 (0.003) 25.4 (1) 31.75 (1.25) 45o/90o

* As defined in paragraph 10.1.1.

Exceptions to the above table are as follows:

a. The pitch and layout guidelines shown above are the minimum starting points


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for economic design. Larger pitch or different layout patterns may be required to satisfy pressure drop or boiling flux requirements.

b. Tube pitch for heavy wall tubes shall not be less than the recommended values in TEMA Table R-7.22.

c. Rotated square layouts (45) are preferable for Laminar Flow. In turbulent flow, especially for pressure drop-limited cases, square layout (90) is preferred.

d. Triangular or rotated triangular pitch shall be used only for non-removable bundle designs.

10.2.3.4. Baffles and Support Plates

a. Permissible types of transverse baffles are segmental, double segmental and the segmental type having no tubes in the window area.

b. Horizontal cut segmental baffles are not acceptable for systems where the shellside fluid is vaporizing after condensing or contains suspended solids.

c. Baffle cut perpendicular to nozzle centerline (normally horizontal cut) is preferred for single phase fluids. Where shellside inlet nozzle has 180o rotation from shellside outlet nozzle, the number of shellside cross-passes must be odd for segmental baffles.

d. The minimum baffle cut for segmental baffles shall be 15 percent of the shell inside diameter.

e. All U-tube bundles shall have full support plate at U-bend. The full support plate shall be trimmed to the extent defined by the baffles outline (on top and bottom) but covering the full tube layout.

f. All baffles shall have a V-notch at bottom to allow draining. In addition, baffles used in 2-phase flow shall have a V-notch on top of the baffle.

10.2.3.5. Bundle Rotation

Where possible, without decreasing the thermal performance of the exchanger, the carbon steel tube bundles shall be designed to allow their operation after being placed back into the exchanger, following a 180 rotation around the bundle's longitudinal axis.

10.2.3.6. Tubesheet

All removable bundles used with a B type front head shall have their stationary tubesheets extended to be equal to the shell flange outside diameter. Tubesheet thickness must be sufficient to eliminate a need for test rings.

Removable bundles used with an A type front head do not need to have full diameter tubesheets.


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Exchangers with extended tubesheets and B type front heads shall be fitted with 100% collar bolts in order to allow shellside hydrotesting with the bonnet removed.

10.2.3.7. Maximum Unsupported Tube Length

The maximum unsupported tube span shall not be more than 0.8 times the values shown on TEMA Table R-4.52.

10.2.3.8. Finned Tubes

Wolverine type S/T (or equal) low and medium height integral fin tubes are acceptable under the following conditions, but require COMPANY approval:

a. The shellside fouling resistance using low fin tubes does not exceed 0.00017 m2 hr C/kcal. Medium height fin tubes are to be used only in gas services with fouling not greater than 0.00017 m2 hr C/kcal.

b. The shellside stream is boiling or in the turbulent flow regime.

c. Their application is economically attractive. As a general guideline finning may be feasible, when the un-finned heat transfer coefficients, corrected for fouling, indicates the shellside coefficient controlling by a ratio of 2:1 or more (low fin tubes may be feasible) and 3:1 or more (medium height fins may be feasible). To avoid fretting of the tubes in baffle/support plates, the baffle and/or support plates shall have a thickness in accordance with TEMA Table R-4.41; however, the minimum thickness shall not be less than 13 mm.

d. High-finned tubing is not permitted.

e. Longitudinally-finned tubes are not allowed for shell and tube exchangers.

f. Circumferentially-finned tubes shall not be finned at the U-bends.

g. Fin height and wall thickness under the fins determine the inside diameter. Wall thickness under the fins and tube diameter greatly affect the cost of finned tubes. Their minimum values are determined by the cleaning requirements of the tube-side fluid, as well as by the tube material selected.

Mechanical cleaning required? yes no Minimum inside tube diameter 15.0 mm 13.0 mm Minimum wall thickness under the fins (carbon steel)

2.0 mm 1.6 mm

Minimum wall thickness under the fins (non-ferrous and stainless steel) (*)

1.6 mm 1.2 mm

(*) Titanium low-finned tubes shall have a minimum wall thickness of 16 BWG/SWG at the bare ends so that the minimum thickness under the fins is


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not less than 0.9 mm irrespective of tube-side mechanical cleaning requirements.

Surface cracking at the fin or wall shall not be accepted.

Low-finned tubes shall be eddy-current tested at the mill.

10.2.3.9. U-Tube Bundle Bend Radius

Bends with radius R < 1.5 times nominal tube OD are not permitted.

10.2.4. Water-Cooled Coolers

10.2.4.1. Cooling water shall be placed on the tubeside and should run upwards through the tubes in order to avoid gas build-up. The tubeside velocity should be as specified in this specification. The tubeside shall be maintained at a positive pressure so that air cannot separate from or be sucked into the water.

10.2.4.2. Cooling Water Velocity

a. Tubeside velocity range for seawater or brackish water shall be as follows:

Tube Material Velocity m/s (FPS)

Titanium 1.5 - 4.6 (4.9-15.1)

70-30 Cu-Ni 1.5 - 3.7 (4.9-12.1)

90-10 Cu-Ni 1.5 - 2.7 (4.9-8.9)

Al Brass, Al Bronze 1.5 - 2.0 (4.9-6.6)

Monel 1.5 - 3.7 (4.9-12.1)

Incoloy 825, Carpenter 20 CB3 1.5 - 3.7 (4.9-12.1)

Incoloy 625, Hastelloy C 1.5 - 3.7 (4.9-12.1)

b. Tubeside velocity range for treated/fresh cooling water shall be as follows:


Carbon and Low Alloy Steel 1.0 - 2.1 (3.3-6.9)

Austenitic Stainless Steel 2.0 - 4.5 (6.6 - 14.8)

Titanium 1.0 - 4.5 (3.3-14.8)

Inhibited Admiralty 1.0 - 2.7 (3.3-8.9)

70-30 Cu-Ni 1.0 - 3.0 (3.3-9.8)

90-10 Cu-Ni 1.0 - 2.5 (3.3-8.2)


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Aluminum, Brass, Alum. Bronze 1.0 - 2.1 (3.3-6.9)

Monel 1.8 - 3.5 (5.9 - 11.5)

Incoloy 825, Carpenter 20 CB3 1.5 - 3.7 (4.9-12.1)

10.2.5. Tubeside/Shellside Selection

In general, tubeside/shellside selection shall be made to satisfy as many as possible of the following points, unless otherwise indicated on Data Sheets:

Service Shell side Tube side

Seawater X

Cooling Water X

Condensing Vapors (except steam) X

Lower Allowable P X

Larger Flow and Similar Properties X

Higher Pressure Fluids X

Corrosive Fluids/Alloy Construction X

*High Fouling Factors X

High Viscosity/Laminar Flow X

* If chemical cleaning can be utilized, the fouling fluid may be placed on the shellside.

10.2.6. Special Applications

10.2.6.1. Slurry Handling

Slurry services shall be routed through the tubeside of the exchanger.

Minimum tube size shall be 25.4 mm (1 in.) OD at 2.77 mm (0.109 in.) (BWG) minimum wall thickness.

Velocity limits for cycle oil containing catalyst fine shall be as listed below. The optimum velocity is 1.75 m/sec (5.74 ft/sec).


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Velocity m/s (FPS)

Maximum Minimum

Straight tube 2.13 (7.0) 1.14 (3.74)

U-Tube 1.75 (5.74) 1.14 (3.74)

Straight tube construction is recommended.

Slurry flow shall be horizontal or downward.

10.2.6.2. HF Acid/Lethal Service

To minimize potential of acid leakage into the process area, exchanger design shall provide as few joint closures as practical.

10.2.6.3. Pulsating Flow on Shellside

Maximum unsupported tube length for vapor or 2-phase flow shall be 914 mm (36 inches).

Design shall include adequate impingement protection plate or a distributor belt so that V2 into a bundle shall not exceed 744 kg/m-s2 (500 lb/ft-s2).

10.2.7. Kettle-Type Reboilers and Evaporators

The shell diameter depends on the required vapor escape area above the tube bundle. Vapor velocities shall nowhere exceed the maximum vapor velocity determined by the entrainment requirements.

These entrainment requirements shall be specified in Data Sheets.

The design shall take into account that frothing is likely to occur above the liquid level. An allowance 125 mm shall be made for this frothing. The height of the escape area above the frothing allowance shall be at least 250 mm.

Minimum of two (2) vapor outlet nozzles shall be used for bundles longer than 4877mm (16 ft).

The entry for vapour / liquid mixtures shall be above the boiling pool. Provision shall be made to separate the vapour phase from the liquid phase by using a deflector plate, spider pipe or other suitable arrangement.

A device recommended for distributing the liquid/vapor mixture above the froth bed is the spider pipe arrangement shown in Figure 1 below:


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Figure 1. SPIDER PIPES

The requirements for spider pipes are as follows:

a. Located at the position of lowest vapor generation

b. The mixed vapor/liquid stream should direct downwards against the shell wall to promote separation of the liquid and vapor

c. No holes in the direct path from the inlet nozzle

d. The velocity head in the inlet nozzle shall be 4000 kg/m-s2 maximum

e. The velocity head in the spider header shall be 1000 kg/m-s2 maximum

f. The velocity head in the holes shall be 4000 kg/m-s2 maximum

If considered necessary, provision shall be made for cleaning the spider pipes.

A vortex breaker shall be provided for the liquid outlet nozzles.

If the liquid level is to be controlled by instrumentation, a calming baffle shall be installed to prevent boiling turbulence from affecting the level instruments.

The liquid space shall be determined by the liquid hold-up requirements.

A distance of 50 mm minimum shall be maintained between the bottom of the bundle and the bottom inside diameter of the shell so as not to obstruct liquid recirculation into the bundle.

Weir plate shall be located behind tube bundle, and it shall be welded tightly to the shell. Weir plate shall have no drain holes and have sufficient height to flood top of top tubes with a minimum of 50 mm of process fluid during normal operation.

The minimum distance between weir plate and the shell head tangent line shall be 1220 mm.

A hold angle shall be provided and placed above the tube bundle to keep bundle in place during shipment and handling. It shall be located directly above and close to the floating head flanges (type T) or the full support plate (at u-bend) when u-tube construction is used.


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10.2.8. Venting and Draining of Exchangers

All shell and tube exchangers, including vertical units, shall be provided with vents and drains allowing complete draining and venting of shellside and tubeside of exchangers, after hydrotest in-situ.

For stacked exchangers of the same service, hydrotest in-situ can be performed in stacked position, but each shell shall be completely drainable and ventable.

Separate vents and drains on exchangers are not necessary if hydrotest in-situ and subsequent draining and venting of exchangers can be accomplished through piping connections or line breaks.

Vertical units shall have vent and drain passages drilled through their stationary tubesheets (including bottom tubesheet of non-removable bundle), exiting out the outside edge and provided with flanged vents and drain nozzles, with blinds and service gaskets.

Total condensers shall be fitted with suitable vents for non-condensables.

For horizontal condensers, shellside vents shall be positioned on top of the shell and located at the furthest point from the shell inlet. Tubeside vents shall be located in the channel at the highest point at the end of the flow path.

For vertical shellside condensers, more than one vent may be required (a high point vent for purging the underside of the tubesheet, and a low point vent for use during start-up).The requirement for, and positioning of, vents on vertical exchangers shall be reviewed on a case by case basis.

10.2.9. Design for Interchangeability

Design of shell and tube heat exchangers for the PROJECT shall target maximum interchangeability of complete units or components.

10.2.10. Shell Diameter

Up to and including a nominal diameter of 500 mm (20 in.) seamless pipe shall be used.

For shells rolled from plate, the nominal shell diameter is the shell inside diameter.

For shells rolled from plate, inside diameters should be changed in 10 mm increments during thermal design or sizing. This requirement can be deviated from in case of high pressure application and when it is economically justified.

10.2.11. Maximum Number of Tube Passes

The maximum number of tube passes shall be 16 for any given heat exchanger.

10.2.12. Connections


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a. The minimum size of any connection shall be 50 mm (2 inches), including vents and drains.

b. Threaded connections/drains/vents are not permitted.

c. Vents and drains shall be Class 300 minimum rating.

d. All nozzle flanges, unless specifically noted otherwise on Data Sheets, shall have Raised Face (RF) and Smooth Finish (SF). Smooth Finish shall be as defined on Project Standard Drawing 5578-E1-STD-MD-B-020.

e. Test connections on process nozzles are not permitted, except for the following two conditions:

For vertical thermosyphon reboilers, directly connected to columns, Temperature Indicators (TI) or Pressure Indicators (PI) are permitted or process nozzle directly connected to the column (when needed for process reasons).

For stacked exchangers, when TI and/or PI are required to be installed on intermediate nozzles, they shall be placed on intermediate nozzles of lower exchanger.

f. For stacked S type shells, vent of lower shell cover and drain of top shell cover shall be elbowed out 90.

g. Reinforcing pads on shellside nozzles are not permitted, if their use will increase inlet or outlet baffle spacings by moving the nozzles location away from the body flanges.

h. The minimum projections for process nozzles shall comply with Project Standard Drawing 5578-E1-STD-MD-B-020.

i. All flanged 2 inch connections shall be minimum rating ANSI Class 300# and shall be braced 90 degrees apart.

10.2.13. Saddles/Supports

a. Saddle design for horizontal exchangers shall comply with Project Standard Drawing 5578-E1-STD-MD-B-012 and 5578-E1-STD-MD-B-061, B-062 and B-063.

b. Support design for vertical exchangers shall comply with Project Standard Drawing 5578-E1-STD-MD-B-060.

10.2.14. Baffle-to-Shell Clearance

For viscous fluids on shellside, with the dynamic viscosity above 2.0 cP at inlet or outlet temperature, the heat transfer coefficient shall be calculated with the baffle-to-shell clearance specified as large. The shellside pressure drop, however, shall


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be calculated with the baffle-to-shell clearance specified as standard/average.

10.2.15. Impingement

a. Impingement protection, in form of impingement plate or two rows of impingement rods, shall be specified for:

Steam heaters with steam on shellside

Two phase flow at inlet

b. For noncorrosive, nonabrasive fluids, nozzles shall be sized to avoid necessity of impingement protection. For designs with nozzles sized to avoid impingement protection, the shell entry area shall be sufficient to obtain comparable values of V2 (within 15-40%) through the nozzle and corresponding shell entry area, but with larger deviations only permitted if V2 is low, otherwise the preferred margin is 10%-15%.

10.2.16. Vibration

Thermal design and sizing process shall include analysis of all aspects of design to avoid or minimize the possibility of vibration.

10.2.17. Tubeside Performance

For gases and vapors, the V2 in tubes shall be less than 7000 kg/m-s2 (4700 lb/ft-s2).

For water, the maximum velocities shall be as listed in paragraph 10.2.4.2.

For liquids (other than water), the V2 shall not exceed 8900 kg/m-s2 (5980 lb/ft-s2).

For two-phase flow, the V2 in the tubes shall be checked carefully against the danger of erosion of the tube ends. In such a case, the velocity and density shall be based on a homogenous gas/liquid mixture.

V is the linear velocity in m/s (ft/s) and is the density in kg/m3 (lb/ft3).

10.2.18. Enhanced heat transfer technology

Proprietary technology such as helical baffles, twisted tubes, tube inserts, etc. may be considered where a significant economic or technical advantage can be realized with little or no detrimental impact to operability and maintainability.

The use of proprietary technology of the type described must be approved by the COMPANY. In such cases, the thermal and hydraulic design and guarantee shall be included in the scope of the technology owner, not the equipment manufacturer (except where the manufacturer is licensed to carry out the design by the technology owner).

Whenever enhanced heat transfer solutions are proposed, the equivalent Base Case


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solution using conventional technology shall be supplied to allow a meaningful comparison.

11. MATERIALS

Materials selection shall be indicated on the Project Equipment Data Sheets.

12. FABRICATION

Project Equipment Data Sheets shall indicate any special fabrication requirements.

13. TESTING

Project Equipment Data Sheets shall indicate any special testing requirements.

1. GENERAL1.1. INTRODUCTION1.2. PURPOSE1.3. DEFINITIONS1.4. EXCEPTIONS

2. CODES AND STANDARDS3. REFERENCE DOCUMENTS4. DOCUMENT PRECEDENCE5. SPECIFICATION DEVIATION/CONCESSION CONTROL6. QUALITY ASSURANCE/QUALITY CONTROL7. DOCUMENTATION8. SUBCONTRACTORS/VENDORS9. HANDLING10. DESIGN10.1. GENERAL REQUIREMENTS10.2. TECHNICAL REQUIREMENTS

11. MATERIALS12. FABRICATION13. TESTING

Documents

5578-E1-SP-ME-001_R0