Dgs-mu-017 - Rev 2

Abu Dhabi Oil Refining Company

DGS-MU-017 Rev- 2 Dec 2013

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev-2

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682) Amendment History

02

Dec 2013

DGS-MU-017 Rev-2

Clause No. 8.5.4.3

DDC

VP(E&TSD)

Dec 2013

SMK / HD

QAM / MAY

June 2009

Clause No. 1.0 Scope Clause No. 3.0 01

June 2009

AMD-MU-017-001BECHTEL

Section # 1.0, 2.0 & 9.0 Clause # 1.4, 4.2.3, 6.1.1.6, 4.2.3, 8.1.3, 8.1.8, 8.2.1, 8.4.1, 8.5.3.1, 8.5.4.1, 8.5.4.2, 8.5.4.4.11, 8.5.4.5g, 8.5.4.7, 8.6.2.2, 8.6.5.2e, 8.6.5.3, 8.6.5.4, 8.6.6.1 & 8.6.6.2, Appendix 1 Annex A, B & G

No

Date

Amendment

Description

Proposed

Approved

Incorporated

DGS History

2

Dec 2013

DGS-MU-017 Rev-2

DGS Discipline Committee

DDC

VP(E&TSD)

1

June 2009

DGS-MU-017 Rev-1

AMD-MU-017-001-BECHTEL

SMK / HD

QAM / MAY

0

Feb 2008

DGS-MU-017 Rev-0

Previous Project

SMK / HD

ETSDM / EPDM

Takreer DGS-MU-017 Rev-2 Dec 2013

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

No

Date

Description

Source

Reviewed

DGS-MU-017 Rev- 2 Dec 2013 Approved

TABLE OF CONTENTS PART I SCOPE ............................................................................................................................... 4 1.0 INTRODUCTION .......................................................................................................... 4 2.0 ALTERNATIVE DESIGNS ............................................................................................ 4 PART II AMENDMENTS / SUPPLEMENTS TO API 682 ................................................................. 4 1.0 SCOPE......................................................................................................................... 4 2.0 NORMATIVE REFERENCES ....................................................................................... 5 3.0 TERMS AND DEFINITIONS ......................................................................................... 6 4.0 SEALING SYSTEMS .................................................................................................... 6 4.1 SEAL CATEGORIES, TYPES AND ARRANGEMENTS .............................................. 6 4.2 OBJECTIVES ............................................................................................................ 7 6.0 DESIGN REQUIREMENTS .......................................................................................... 8 6.1 COMMON DESIGN REQUIREMENTS (ALL CATEGORIES) .................................... 8 7.0 SPECIFIC SEAL CONFIGURATIONS ........................................................................ 10 7.2 ARRANGEMENT 2 SEALS ..................................................................................... 10 8.0 ACCESSORIES ......................................................................................................... 11 8.1 AUXILIARY PIPING SYSTEMS ............................................................................... 11 8.2 MECHANICAL SEAL FLUSH/COOLING SYSTEMS (GROUP I) ............................. 11 8.3 QUENCH SYSTEM (GROUP II) .............................................................................. 12 8.4 COOLING WATER SYSTEMS (GROUP III) ............................................................ 12 8.5 ACCESSORIES AND AUXILIARY SYSTEM COMPONENTS ................................. 12 8.6 BARRIER/BUFFER FLUID AND SEAL FLUSH POSITIVE CIRCULATING DEVICES ................................................................................................................................ 17 9.0 INSTRUMENTATION.................................................................................................. 18 10.0 INSPECTION, TESTING AND PREPARATION FOR SHIPMENT............................... 18 10.1 GENERAL ............................................................................................................... 18 10.2 INSPECTION .......................................................................................................... 18 10.3 TESTING ................................................................................................................. 18 11.0 DATA TRANSFER ...................................................................................................... 19 11.1 GENERAL ............................................................................................................... 19 APPENDIX 1 SEAL SELECTION PHILOSOPHY ......................................................................... 20 ANNEX A RECOMMENDED SEAL SELECTION PROCEDURE ............................................. 24 ANNEX G.32 API 682 PLAN 53 MODIFIED, TYPE 1 WITH AIR FIN TUBE (NATURAL CONVECTION) OR WATER COOLING .................................................................. 28 ANNEX G.33 API 682 PLAN 53 MODIFIED, TYPE 1 WITH AIR FIN TUBE (NATURAL CIRCULATION) OR WATER COOLING FOR BETWEEN BEARINGS PUMP ......... 29 ANNEX G.34 API 682 PLAN 53 MODIFIED, TYPE 2 WITH AIR FIN TUBE (NATURAL CIRCULATION) OR WATER COOLING .................................................................. 30 ANNEX G.35 API 682 PLAN 54 MODIFIED .................................................................................. 31 ANNEX G.36 API 682 PLAN 52 .................................................................................................... 32 ANNEX G.37 MAKE-UP SYSTEM FOR API PLAN 53 MODIFIED AND/OR 52 SEAL SYSTEMS . 33 ADDENDUM SHEET ...................................................................................................................... 34

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

LIST OF AUTHORIZED SIGNATURES INITIALS DGS Discipline Committee Member, ADRD

Ramesh Rao Kaliyamurthy

DGS Discipline Committee Member, RR

Soman Mukherjee

DGS Discipline Committee Member, E&TSD

Megharaj Laxman Mane

DGS Discipline Committee Leader, E&TSD

Abdulla Musaed Al Harthi

Standards & Procedures S/H, E&TSD

Abdulla Musaed Al Harthi

Vice President, E&TSD

Salem Obeid Al Dhaheri

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

PART I SCOPE

1.0

INTRODUCTION This specification contains the requirements and recommendations for the selection of shaft seals and their related environmental control systems for centrifugal and rotary pumps. This specification is based on and shall be used in conjunction with API 682, 3rd edition September 2004. Part II of this specification amends, supplements and deletes various clauses of API 682. Clauses of API 682 that are not modified shall remain completely valid as written. This specification supplements the requirements specified on the individual Equipment Data Sheets. Where conflicts exist, the Data Sheets shall govern. This Specification is intended for use in oil refineries, gas plants, chemical plants and all utility facilities. Where national and/or local regulations are more stringent than those specified in this Specification, the CONTRACTOR shall determine which of the requirements are the more stringent and which combination of requirements will be required with respect to safety and environmental issues. In all cases the CONTRACTOR shall inform the COMPANY of any deviation from the requirements of this Specification that are necessary to comply with national and/or local regulations.

2.0

ALTERNATIVE DESIGNS The acceptance of alternative designs shall be subject to the prior approval of COMPANY. Seal MANUFACTURERS shall review all seal applications as submitted by pump VENDORS. The seal MANUFACTURER shall notify the pump VENDOR and COMPANY if a deviation from the requirements in the data sheets or this specification would result in equal or improved sealing based on their seal experience on similar applications PART II AMENDMENTS / SUPPLEMENTS TO API 682

1.0

SCOPE [Add] This standard applies to the shaft sealing equipment commonly supplied for the specified service(s) which will meet the objective of at least five years of uninterrupted service while complying with the specified emission regulations.

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

This specification covers the minimum requirements for shaft seals and their sealing systems for centrifugal and rotary pumps. The applications addressed in this specification cover sealing duties for pumps with a working temperature range of -40 to +400 °C and a maximum allowable working pressure up to 42 bar (abs). It covers seals for pump shaft diameters from 20 mm to 110 mm. Seal applications outside these boundaries are subject to the same design and configuration, shall be termed as “Engineered Seals” and shall require COMPANY's approval. The seal Vendor shall supply references of seals in similar services. 2.0

NORMATIVE REFERENCES [Add to end of references:] It shall be the VENDOR’S responsibility to be fully knowledgeable of the requirements of the referenced Codes and Standards. The following reference documents form an integral part of this specification. When an edition date is not indicated for a document, the latest edition in force at the time of CONTRACTOR’S/VENDOR’S proposal submittal shall apply. American Standards API 682

Shaft Sealing Systems for Centrifugal and Rotary Pumps

NACE MR0103

Materials Resistant to Sulfide Stress Cracking in Corrosive Petroleum Refining Environments

NACE TM0103

Laboratory Test Procedures for Evaluation of SOHIC Resistance of Plate Steels Used in Wet H2S Service

NACE TM0284

Evaluation of Pipeline and Pressure Vessel Steels for Resistance to Hydrogen-induced Cracking

British Standards EN 10204

Metallic Materials – Types of Inspection Documents

Design General Specifications DGS-IU-007

Instruments Furnished with Package Units

DGS-MG-001

Centrifugal Pumps (Amendments / Supplement to API 610)

DGS-MG-003

Centrifugal Pumps for General Services

DGS-MG-004

Positive Displacement Pumps – Rotary (Amendments / Supplement to API 676)

DGS-MU-006

Rotating Equipment – Minimum General Requirements

DGS-MU-007

Rotating Equipment System Integration

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

3.0

TERMS AND DEFINITIONS

3.79

[New] HAZARDOUS AND TOXIC SERVICE – This specification defines hazardous and toxic service for mechanical seals and their related seal systems as a service used in one or more of the following categories: Category 1: •

Liquids containing hydrogen sulphide in concentrations above 500 ppm.

•

Liquids containing lethal substances as indicated in the data sheet. Examples of lethal substances include but are not limited to: HF acid, phenol, concentrated sulphuric and nitric acid.

Category 2: •

Liquids containing toxic substances as indicated in the data sheet. Examples of toxic substances include, but are not limited to, benzene, toluene, MEK, and ethylene oxide.

•

Hydrocarbon liquids operating at design or emergency off design temperatures above their auto-ignition temperature.

Category 3: •

Hydrocarbon liquids with a seal chamber vapour pressure higher than 5 bar (abs).

•

Hydrocarbon services of butane (C4) or lighter.

3.82

Plan 54 (Plant wide) - Is a plan 54 where the external seal flush is supplied from plant-wide system engineered and supplied by the buyer.

3.83

Plan 54 (Stand-alone) - Is a plan 54 where the external seal flush is supplied from a Standalone seal support console engineered and supplied by the seal supplier. There will be one such console per pump. The external flush fluid shall have dual pumps, one running and one stand by.

4.0

SEALING SYSTEMS

4.1

SEAL CATEGORIES, TYPES AND ARRANGEMENTS [Add] Refer to Appendix 1 – Seal Selection Philosophy for general guidelines on seal selection.

4.1.1

[Add] The inner seals of arrangement 2 mechanical seals shall be designed with a positive means of retaining the sealing components. They shall be designed with sufficient closing force to prevent the faces from opening upon pressurization of the buffer fluid to the maximum specified back pressure from the connecting flare or vent system or 4.5 bar (abs), whichever is higher. In the design for this condition the prevailing normal suction pressure of the pump may be taken into account.

4.1.5

[Add] A back-to-back (face-to-face) seal arrangement shall be considered if the required differential pressure across the inner seal (due to a specified high barrier pressure versus a low seal chamber pressure) is considered too high to ensure a reliable operation with a tandem arrangement.

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682) 4.2

OBJECTIVES

4.2.1

[New] SEAL SELECTION

DGS-MU-017 Rev- 2 Dec 2013

Mechanical seal application details shall be as specified in the data sheets of the pump and on the API 682 data sheet. Seals shall be selected to achieve a minimum of five years of uninterrupted operation. The following applications require the specific pre-approval of COMPANY: •

Plan 54 for dual seals in Category 1 liquid services, see paragraph 3.79

•

Dual unpressurized tandem seals with Plan 52 in Category 2 services, see graph 3.79

•

Single seals with auxiliary seals, other than dry gas seal types.

para-

Seals and seal arrangements and seal piping shall be selected in accordance with Annex A. Part 1 of Annex A presents the requirements of this sub-section in graphical form. Part 2 of Annex A presents the requirements for dual seal arrangements and their related seal plans and piping. Dual seals shall be applied in the following services: 1.

Hazardous services (see paragraph 3.79)

2.

Services in which the required five year operation cannot be ensured with a single seal application due to the physical or chemical properties of the liquid to be sealed.

3.

Services in which it is not permitted for the pumped liquid to enter the flare or atmosphere. In this case, dual pressurized seals shall be applied.

Dual pressurized seals shall be applied for the following services as a minimum: a.

If the available seal liquids are not compatible with the required seal conditions to obtain the required five years life.

b.

Hazardous and toxic service (as defined in Specification DGS-MU-006 and paragraph 3.79 above).

c.

Services containing H2S which upon seal failure will result in an H2S leakage rate to atmosphere exceeding 1g/s.

d.

Fluids with specific gravity less than 0.7.

e.

Operating temperatures higher than 200°C.

If dry running dual seals are not used, Plans 52, 53 A/B or 54 shall be used. Nitrogen cylinders and/or sealant refill equipment kit shall be in CONTRACTOR’S scope. If the presence of abrasive particles at the seals can not be avoided, the pump shall be an API 610 slurry type pump with expellers and both seal faces shall be of hard material. 4.2.2

[New] Proposals for dry gas seal arrangements in pumps versus standard dual seal applications are subject to the pre-approval of COMPANY and shall be limited to the following: 1.

A single liquid seal and a dry gas back-up seal arrangement may be considered only for liquids not classified as Category 3 as defined in paragraph 3.79;

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682) 2.

DGS-MU-017 Rev- 2 Dec 2013

Dual pressurized dry gas seal arrangements with a pressurized nitrogen barrier may only be considered for liquids that are not classified as hazardous (see paragraph 3.79) and have a maximum vapour pressure at pumping temperature of 1.05 bar (abs). Attention shall be paid by the CONTRACTOR in this application to ensure a reliable nitrogen supply system.

6.0

DESIGN REQUIREMENTS

6.1

COMMON DESIGN REQUIREMENTS (ALL CATEGORIES)

6.1.1.1

[Add] Bolting or set screws used to assemble seal cartridges shall have sufficient strength to withstand the force needed to remove the cartridge from the pump, taking into account the high friction which may be present due to deposits between the shaft and the shaft sleeve.

6.1.1.6

[Replace the last sentence by] The static sealing pressure rating (SSPR) of mechanical seals shall be greater than or equal to the maximum static sealing pressure (MSSP), which shall be calculated as indicated below. For Arrangement 1 seals, the MSSP of each seal shall be equal to the maximum static seal chamber pressure that can occur in the pump. Unless otherwise specified, this shall be the shut-off pressure of the pump at maximum suction pressure. For Arrangement 2 seals, the MSSP of both the inner and outer seal shall be equal to the maximum static seal chamber pressure that can occur in the pump. Unless otherwise specified, this shall be the shut-off pressure of the pump at maximum suction pressure. For Arrangement 3 seals, the MSSP of the outer seal shall be equal to the maximum static seal chamber pressure that can occur in the pump. Unless otherwise specified, this shall be the greater of 1) shut-off pressure of the pump at maximum suction pressure or 2) the maximum barrier fluid pressure. The MSSP of the inner seal shall be the greater of 1) differential between the maximum barrier fluid pressure and the minimum seal chamber pressure or 2) the maximum differential between maximum seal barrier fluid pressure and atmospheric pressure.

6.1.1.11

[Add] Unless otherwise specified by COMPANY, single mechanical seals in vacuum service shall be of the metal bellows type and shall be suitable for the lowest specified static or dynamic seal chamber pressure.

6.1.2

Seal Chamber and Gland Plate •

6.1.2.14

[Replace the 2nd sentence in 2nd paragraph by] Where seal chamber conditions do not meet the specified margins or where sealing pressures are higher than 5 Bars, the seal MANUFACTURER shall: c) [Replace] furnish the seal gland plate or the seal chamber with a second flush connection and a pressure gauge (minimum 4” dial size) to permit measurement of seal chamber pressure directly [Delete] The NOTE: 2nd paragraph, “Lowering the flush…over vapour pressure”. [Add] The dynamic seal chamber pressure for single seals or for the inner seal of an unpressurized dual tandem seal arrangement shall exceed the maximum pumped liquid vapour pressure at maximum seal chamber liquid temperature by at least 3.5 bar or 10%, whichever is higher.

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

In addition, for pumped liquids with a seal chamber vapour pressure above 10 bar (abs), the seal chamber pressure and temperature of the liquid shall be such that a temperature rise of 10°C will not result in vapour formation. The margins required in the above paragraphs shall be achieved by raising the seal chamber pressure to the required pressure. The first choice is to apply seal flush plan 11 for a hydraulically balanced pump impeller or plan 13 for a hydraulically unbalanced impeller design. Alternatively the margin may be achieved by lowering the seal chamber temperature by applying seal flush plan 21 or 23. If the pump differential head is too low to achieve the above required margins, the MANUFACTURER shall provide alternative proposals, subject to the approval of COMPANY, in order to ensure an adequate seal environment. 6.1.2.15

[Add the following after “-to isolate the seal chamber fluid; and/or”:] - to control the flow in conjunction with a fixed orifice in the seal flush supply or return line [Delete] “-to control the flow into or out of the seal chamber” [Add] A throat bushing shall not be used to control the flow into or out of the seal chamber. For this purpose a fixed orifice shall be provided to restrict the circulation of the flushing liquid.

6.1.2.19

[Add] Unless otherwise specified, the connection between the seal flush piping and the gland plate shall be full penetration butt welded if the pressure class of the pump flanges is ANSI rating class 900 or higher.

6.1.2.20. b [Add] For vertical pumps, the vent connection shall be provided with a flanged valve and blind. The vent valve and blind flange shall be AISI 316L stainless steel unless otherwise specified by COMPANY. Seal gland plates shall have a drain connection if they have a throttle bushing or an auxiliary sealing device. 6.1.2.23

[Add at the beginning of the clause] Premium carbon floating throttle bushing shall be furnished for both single and dual seals.

6.1.3

Cartridge Seal Sleeves

6.1.3.1

[Add] In applications where the shaft requires additional corrosion protection, an intermediate sleeve of the same material as the seal shaft sleeve shall be provided between the impeller and the seal shaft sleeve. Appropriate secondary (O-ring) sealing devices shall be installed between the sleeves and the impeller in order to ensure complete protection of the shaft.

6.1.3.3

[Add] Shaft sleeves for pusher type seals shall have a hard face coating at the area of the dynamic sealing element, unless otherwise specified or approved by COMPANY. Coatings shall be fully compatible with the pump liquid and the barrier or buffer liquid. The approval of COMPANY is required for the type of coating and the application procedure of the coating for seal sleeves in corrosive services.

6.1.3.5

[Add] If dual pressurized seal arrangements for Category 1 liquids (see paragraph 3.79) are applied, an additional O-ring seal between the shaft and the sleeve shall be located at the outboard end of the sleeve. The space in between the two O-rings under the sleeve shall be buffered with the barrier liquid by means of two holes drilled in the shaft sleeve.

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

6.1.3.12

[Add] Where seals must seal against an MSSP of more than 50 bar (abs), designs using set screws for positioning the shaft sleeve are subject to the approval of COMPANY.

6.1.3.13

[Replace] “When specified by the purchaser or recommended by the seal MANUFACTURER,” with the words “If the MSSP of the seal exceeds 50 bar (abs),” [Add] Alternative designs to the split ring construction, API 682, page 33, Figure 20, require the specific approval of COMPANY.

6.1.6

Materials

6.1.6.1

General

6.1.6.1.1 [Add] Seal materials shall comply with NACE MR0103, as applicable, for services with H2S levels defined therein. The seal MANUFACTURER shall recommend alternative mechanical seal materials where they consider the specified combination unsuitable. In all cases, the seal MANUFACTURER shall indicate type, grade and supplier of the materials. Seal types and materials shall be approved by the CONTRACTOR. Solid PTFE Orings are not acceptable for sealing between the rotating seal parts and the shaft sleeve. Copper or bronze filled carbon or other copper bearing materials shall not be used for services involving contact with carbonates, high concentrations of H2S, ammonia, ammonium chloride, and acetylene. 6.1.6.2

Seal Faces

6.1.6.2.3 [Add] Carbon ring material for seal faces shall be suitable for continuous operation at the highest temperature specified for the pump in which the seal is incorporated. Alternatively, silicon carbide material may be used if approved by COMPANY. Delete the second sentence “if specified…” 6.1.6.5

Secondary Sealing Components

6.1.6.5.2 [Replace the first sentence by:] Fluoroelastomers shall not be used in seals operating at a pumping temperature above 175 °C. Perfluoroelastomers shall not be used in seals operating at a pumping temperature above 240 °C. If alternatives are available that are equal to or better than perfluoroelastomers in the applicable service, they may be applied subject to the approval of COMPANY. 6.1.6.5.4 [New] O-rings made of solid PTFE material shall not be used. 6.1.6.6

Metal Bellows [Add] Alternative bellows materials for standard seals may be used if they have a proven service record in the specified duty and if approved by COMPANY.

6.1.6.10.5 [Add] 100% magnetic particle inspection or liquid penetrant inspection of all welds shall be performed. Requirements of 100% radiographic inspection will be addressed in the requisition/data sheets. 7.0

SPECIFIC SEAL CONFIGURATIONS

7.2

ARRANGEMENT 2 SEALS

7.2.1.2

[Delete]

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

7.2.1.3

[Replace 1st sentence with] Dual seals with dry running secondary seals are preferred, but shall not be furnished for hazardous services. If dual seals are required, bellows type dry running seals shall be provided for operating temperatures 150°C or higher. All applications for dry running seals shall be approved by the COMPANY.

7.3.1.1

[Add] For dual pressurized systems the barrier medium shall be compatible with the process fluid, and the barrier pressure shall be controlled between 2 to 4 bars above the maximum seal chamber pressure which can develop at any point on the pump performance curve.

8.0

ACCESSORIES

8.1

AUXILIARY PIPING SYSTEMS

8.1.3

[Replace with:] Unless specified otherwise, the seal Vendor shall supply all flush coolers and instrumentation associated with the flush plans being applied. Unless specified otherwise, the pump Vendor shall supply and fit all orifices, interconnecting pipework and other items associated with the flush plans being applied. All auxiliary piping systems, except Plans 52 and 53 shall be mounted within the confines of the associated pump’s baseplate area. Plan 52 and Plan 53 systems may be mounted either on or off the pump baseplate, as specified on the datasheet. If mounted on the baseplate then the interconnecting pipework (and associated drain and vent) shall be supplied and fitted by the pump Vendor. If mounted off the baseplate then interconnecting pipework (and associated drain and vent) shall be supplied and installed by the CONTRACTOR, unless specified otherwise.

8.1.5

[Replace with:] Auxiliary piping systems shall not use tubing unless approved by COMPANY. Piping shall have flanged connections unless otherwise approved by COMPANY. Primary seal plans, such as 11, 13, 21, 23 and 32, shall be furnished with welded or flanged connected piping.

8.1.8

[Replace the last two sentences of this clause by:] Threaded connections shall be limited to the final connections at the gland plate only. The last flanged connection before the gland plate shall be made with a lap joint flange at the gland plate side in order to facilitate proper flange alignment after maintenance. Pipe bushings and seal welds shall not be used. All fabricated joints in seal system piping shall be full penetration butt welded and the weld root shall be made by gas tungsten arc welding (GTAW). Socket welds shall be used only with the approval of COMPANY.

8.1.17

[Add to the beginning of the first sentence of this clause:] "On the gland plate, ...."

8.1.20

[New] If the outside temperature of seal system piping and its components is higher than 70 °C, personnel protection shall be provided for parts which are within the reach of personnel.

8.2

MECHANICAL SEAL FLUSH/COOLING SYSTEMS (GROUP I)

8.2.1

[Add] However, the seal MANUFACTURER shall remain responsible for the combined performance of the seal and seal system in accordance with this specification. Standard seal flush plans 1, 2, 12, 14, 22, 31, 41 and 53C shall not be used.

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

This Specification provides replacement piping and instrumentation schematics for G.14 (Plan 52), G.16 (Plan 53B), and G.18 (Plan 54). For the following services, a suitable clean liquid from an external source shall be injected per Plan 32. The source shall be reliable and available continuously, including during start-up and shut down.

8.3

a.

Very dirty liquids

b.

Very corrosive liquids for which suitable seal materials are not available

c.

Toxic materials

QUENCH SYSTEM (GROUP II) [New] d.

Seal quench piping shall include a fixed metering orifice for the required quenching capacity for each mechanical seal. An appropriate steam trap and condensate drain shall be installed as close as practical to the pump in order to ensure a dry steam supply to the gland plate in the steam piping to the seal.

e.

The quench drain shall be piped to the base plate drain.

8.4

COOLING WATER SYSTEMS (GROUP III)

8.4.1

[Replace with] Details of Cooling Water System are as given in Basic Engineering and Design Data.

8.4.3

[Replace] Sight flow indicators (closed type) shall be furnished in each outlet line.

8.4.4

[Replace] Vendor shall provide manifolded and valved inlet and outlet connections at the edge of the baseplate for single point connection by the purchaser.

8.5

ACCESSORIES AND AUXILIARY SYSTEM COMPONENTS

8.5.1

Cyclone Separator [Replace this whole clause, from 8.5.1.1 to 8.5.1.4 inclusive, with:] Cyclone separators shall not be used unless approved by COMPANY for a specific application. Cyclones integral with the pump casing are not permitted. Cyclones in flushing lines may be used only with approval of the COMPANY and where the MANUFACTURER can demonstrate satisfactory performance. (Note: Although definitive limits cannot be given, the PURCHASER may approve the use of cyclones only where there is a low concentration of high density solids and there is a marked difference in density between the liquid and the solids.) Strainers shall not be used in the recirculation line.

8.5.3

Seal Flush Coolers

8.5.3.1

[Add] Coolers can be either water-cooled or air-cooled. For plans 21, 23, 52 and 53M (modified), air cooling shall be the first choice. Water cooling for Plan 53M (modified) in hazardous services is subject to the approval of COMPANY.

8.5.3.2

[New] The construction of the cooler and its piping configuration shall allow full accessibility to the cooling water side for cleaning purposes.

8.5.4

Barrier/Buffer Fluid Reservoirs/Accumulators

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

[Add] Liquid barrier seal systems shall be in accordance with paragraph 8.2. The type of barrier seal system arrangement shall be specified on the mechanical seal data sheet. A dual seal barrier system may contain either a fluid or a clean dry inert gas (e.g. nitrogen) in a dual pressurized gas seal application or a dry gas back-up seal application. 8.5.4.1

[Add] Make up barrier fluid connections shall be provided so that each connection is colour coded and unique to a barrier fluid. The requirement is to minimize the risk of using an incorrect barrier fluid for topping up.

8.5.4.2

[Add at the end of the sentence] ",where applicable for the selected seal barrier system". [Delete] Figure G.27 a)

[Replace this clause by:] Plan 52 systems shall be provided with a separate reservoir for each seal. Plan 53 M (modified) systems shall be provided with a separate accumulator for each seal.

c)

[Modify] 1 meter (3 feet) to 1.5 meters (5 feet).

d)

[Add] In order to minimize the pressure drop within the system, pipework shall be not less than 3/4 inch diameter.

f)

[Add] A means of filling and re-charging the seal system shall be provided. Refer to Annex G.37 for details of scope. Seal vendors are to review the pipework and fittings used in the construction of the seal support piping systems and confirm that the circulating device recommended can achieve the required flow rates with the proposed seal buffer fluid.

8.5.4.3

h)

[Replace] “Switch” with “Transmitter.” [Modify the last sentence] The transmitter shall provide indication and alarm on an increasing (High) pressure. In addition for pressurized dual mechanical seals (Arrangement 3), an alarm on Low pressure shall also be provided. CONTRACTOR shall provide a selector switch in the plant control system to use these signals either for alarm only or for alarm and trip.

i)

[Replace with] The reservoir shall be equipped with a level transmitter with level indication, low level alarm and high level alarm. The transmitter shall be mounted in a standpipe arrangement with isolation, drain and vent valves for maintenance. CONTRACTOR shall provide a selector switch in the plant control system to use these signals either for alarm only or for alarm and trip.

[Delete] Figure G.27 a)

[Add] Reservoirs for atmospheric or low pressure buffer liquid and accumulators for pressurized barrier liquid shall be sized to allow at least 25 days between manual refills based on the seal leakage rate specified by the seal MANUFACTURER. This shall not compromise the specified seal life time.

b)

The accumulator shall be equipped with a pressure gauge to monitor the Nitrogen pre-charge pressure.

8.5.4.4.4 [Add] The following shall also be stamped on the seal reservoir nameplate: •

Vessel Tag Number

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682) •

Pump Tag Number

•

Reservoir Capacity

DGS-MU-017 Rev- 2 Dec 2013

8.5.4.4.9 [Delete] “If specified,” 8.5.4.4.10 [Replace this clause by:] All connections to the reservoir shall be provided with weld neck flanges in accordance with the Specifications stated on the requisition. 8.5.4.4.11 [New] The rating of the reservoir shall be at least equal to the MAWP of the pump casing. 8.5.4.5g

[New] The CONTRACTOR shall include a provision enabling back flushing of the cooling coil.

8.5.4.6

[New] Barrier seal systems are given in clauses 8.2 through 8.4. The use of any other type of barrier seal system versus those specified below is subject to COMPANY approval. Low pressure or non-pressurized buffer liquid systems shall be in accordance with Annex G.36, plan 52 system.

8.5.4.7

[New] Variable pressure barrier system API 682 Plan 53M (modified) - Type 1 (see Annex G.32). For between bearing pumps, each seal shall be individually supported, as shown in Annex G. 32. (i.e. Annex G33 shall not be used.) This barrier system is used for dual pressurized seal arrangements. It is typically used in back-to-back or face-to-face seal arrangements where the barrier system pressure is substantially higher than the normal seal chamber pressure. This system can also be used with dual tandem seals if the individual seal pressure rating permits. For Category 1 liquids the barrier pressure shall be above the maximum static and dynamic pressure occurring in the pump in any possible upset condition, such as at pump maximum discharge pressure. For Category 2 and 3 liquids and if applicable, other liquids, the barrier pressure shall be set above the maximum seal chamber pressure that can occur during operation of the pump. The barrier liquid is normally circulated by a pumping ring and is cooled by a finned tube natural convection air cooled heat exchanger. The seal MANUFACTURER shall establish the temperature rise of the liquid and size the cooling system so that the maximum liquid temperature during operation will not exceed 80 °C. If this requirement results in over sizing of the finned tube cooler, water cooled coolers may be considered, subject to the approval of COMPANY. The Plan 53M (modified) system uses a bladder-type accumulator that contains a liquid volume to compensate for the seal leakage across the inboard and outboard seals. The gas pre-charge pressure of this bladder-type accumulator, when empty of liquid, shall be 1 kg/cm2 higher than the highest pressure that can occur in the pump seal chamber as specified above. Bladder-type accumulators shall be pre-charged with nitrogen only. The accumulator shell pressure rating shall exceed the maximum possible supply pressure of the nitrogen pre-charge supply facilities. Accumulators shall be se-

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

lected from the MANUFACTURER’s standard range of commercially available pressure designs. The total working volume in the accumulator is the volume required to fill the accumulator from empty (with pre-charged nitrogen in the bladder) to the maximum barrier system pressure. Typically this volume results in a pressure increase from 4 to 8 kg/cm2 above the nitrogen pre-charge pressure. The required operating volume of the accumulator is established by the seal leakage rate (inside and outside seal) and the specified refill frequency of the barrier system. This operating volume shall be limited to 70% of the total working volume, in order to include emergency reserve of 30%. This reserve level shall be indicated by means of an appropriate setting of the low pressure alarm on the system. Unless otherwise approved by COMPANY, the normal refill interval shall be at least 25 days. The refill or topping-up of these barrier systems should be done via a hard piped barrier fluid make-up system which has a positive barrier between its fluid supply side and the barrier fluid header. A typical example is provided in Annex G.37. Each barrier system shall be connected to the header of this make-up system by means of double block valves with a filter in between or spring return ball valves which shall normally be closed and only opened for refilling or topping up. In this way the barrier systems are isolated from each other and cross contamination and pressure disturbance effects are prevented. Depending on location and service conditions, a relief valve may be installed to prevent over-pressurising the system on the liquid side. Unless otherwise approved by COMPANY, individual barrier systems and barrier fluid make-up systems, including barrier fluid header piping, shall be made of austenitic stainless steel. Bladder-type accumulator shells may be carbon steel. Bladder materials shall be MANUFACTURER’s standard, unless otherwise specified by COMPANY, and shall be compatible with the barrier liquid. Each barrier system shall be provided with a permanently attached stainless steel name plate, which shall indicate at least the following:

8.5.4.8

•

Pump item number

•

Barrier fluid

•

Pre-charge nitrogen pressure

•

Minimum and maximum barrier pressure

•

Pressure alarm setting

•

Year of construction

•

Materials of Construction

[New] Constant differential pressure ratio barrier system API 682 Plan 53M (modified) - Type 2 (see Annex G.34). This sealing system may be used under restricted conditions; it is considered suitable only for clean and non-aggressive, non-corrosive services, typically in low temperature service below minus 25 °C.

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

The barrier system contains an accumulator with a differential piston-type pressure amplifier whereby a positive differential pressure across the primary seal is maintained at a fixed pressure ratio. This differential pressure is created by the difference between the piston areas of the barrier liquid side and the process pump side of the amplifier and may be increased either by a spring or by a weight. Cooling may be provided by an internal cooler inside the accumulator or by a separate natural convection fin tube cooler or water cooler. Since the barrier fluid of this system may be contaminated by the pump liquid, it shall only be applied in those services where contamination is permitted. Unless otherwise approved by COMPANY, individual barrier systems and barrier fluid make-up systems, including barrier fluid piping, shall be made of austenitic stainless steel. 8.5.4.9

[New] Circulation barrier system API 682 Plan 54 modified (see Annex G.35). This barrier system is used for dual pressurised seal arrangements. This system is applied for Category 2 liquids. Subject to COMPANY’s approval, it may be used for liquids containing H2S in Category 1. Two basic systems are possible: 1.

A once-through circulation barrier system, which is based on a slip stream from the process that is returned to the process after having passed through the seals.

2.

A full re-circulation system with partial replenishment to maintain the required degree of barrier liquid cleanliness.

The systems shall have controlled supply and return pressures. The differential pressure between the controlled supply and controlled return pressures shall be between 4 kg/cm2 and 6 kg/cm2. The barrier liquid pressure between the seals shall be set so that leakage of pump liquid into the barrier system is positively prevented, either dynamically or statically. For this reason the barrier pressure between the dual seals shall be at least 2 kg/cm2 higher than the maximum pressure that can occur in the pump seal chamber. As far as practical, this maximum pressure shall be the highest discharge pressure of all pumps connected to the system, but allowance may be made for the maximum reverse pressure capabilities of the inner seal in static condition. The use of dual pressurised tandem seals may also be considered in order to maintain the inner seal integrity during upset conditions. The barrier liquid pressure between the seals for plan 54 circulation systems should not exceed 26 kg/cm2(a). If higher pressures are required, the use of individual circulation systems or special plan 53M (modified), Type 1, arrangements should be evaluated. In the design of a barrier system for multiple pumps, careful consideration shall be given to the inclusion of high pressure multi-stage pumps. As these high pressure pumps are a potential contamination hazard for the barrier system, the use of dedicated barrier systems for these pumps should be considered. If these pumps are in non-spared essential service, separate barrier systems shall be the first choice. Takreer DGS-MU-017 Rev-2 Dec 2013

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

The barrier system shall be designed so that each seal cartridge has alarms to indicate either a primary or secondary seal failure and loss of barrier pressure. The filtration of the barrier liquid shall be 50 μm. The system shall have full flow double filters with continuous transfer valves. Each seal cartridge shall include a block valve, non-return valve, flow indicator, restriction orifice, dual seal, pressure indicator and alarm and restriction orifice (Annex G.35). The circulating seal liquid stream may be totally or partially routed back to the process by others. Depending on the degree of contamination a run-down connection for piping by others to the slops systems shall also be provided to flush the system. The system shall be equipped to detect major seal leakage by measuring the supply and return flows of the barrier system and/or tank level. The operating temperature may vary depending on the selected barrier liquid. If required, insulation and heat tracing of supply and return lines shall be provided to prevent excessive viscosities during start up and/or during off-design conditions. Unless otherwise approved by COMPANY, the total system including all supply and return piping shall be made of austenitic stainless steel, except for the booster pumps. 8.5.5.1

[Delete]

8.5.5.2

[Replace with:] The seal Vendor shall select and recommend the barrier/buffer fluid and seek COMPANY and CONTRACTOR approval with regard to availability and compatibility with process fluid.

8.6

BARRIER/BUFFER FLUID AND SEAL FLUSH POSITIVE CIRCULATING DEVICES

8.6.1

[Replace the last sentence of this clause by:] The purchaser and mechanical seal MANUFACTURER shall agree upon which type of circulating device shall be provided. The seal MANUFACTURER remains responsible for the performance of the seal and seal system in accordance with this specification.

8.6.2.1

[Add to the end of this clause:] However, this is not limited to Figures G.29 and G.30.

8.6.2.2

[Add] Seal vendors shall provide the performance curve for head versus flow for the recommended circulating device.

8.6.3.1

[Replace the last sentence of this clause by:] The circulation pump, provided by others, shall be selected by the MANUFACTURER. The type of pump is subject to the approval of COMPANY.

8.6.4.1

[After the first sentence of this clause, add new sentence:] The seal MANUFACTURER shall investigate these characteristics for final acceptance of the fluid to be applied.

8.6.4.2

[Delete] “If specified,” [Add] The seal Vendor shall confirm suitability of the selected external flush fluid.

8.6.5.2e

Replace “Switch”, with “Transmitter”

8.6.5.3

Replace “Switch”, with “Transmitter”

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

8.6.5.4

[Add] All containment seal systems shall be provided with a test connection and a testing kit. The testing kit scope shall be as defined in Figure 1.

8.6.6.1

[Add] Barrier/buffer gas system connections shall be routed so that they are accessible to operators standing at grade level alongside the seal system.

8.6.6.2

Replace “Switch”, with “Transmitter”

9.0

INSTRUMENTATION [Delete entire sections 9.1 through 9.10] [Add] All instrumentation shall be provided as per Specification DGS-IU-007. Wherever switches are referred to, transmitters are to be supplied. All controls and instruments shall be located no higher than 1.8 m above grade, in order to permit easy visibility by the operators, as well as accessibility for tests, adjustments, and maintenance. Where it is envisaged that ladders will be required, the vendor shall supply a safe working platform with stairs to reach the working platform.

10.0

INSPECTION, TESTING AND PREPARATION FOR SHIPMENT

10.1

GENERAL

10.1.7

[Modify the first part of sentence from:] “If specified, the purchaser, the vendor, or both” to “The COMPANY, CONTRACTOR and the VENDOR”

10.2

INSPECTION

10.2.3k

[Add] As a minimum, hardness shall be verified where similar requirements have been specified for wetted components of the pump on the pump data sheet.

10.3

TESTING

10.3.5.1

[Add to the beginning of the paragraph:] “For dual seals or”

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

11.0

DATA TRANSFER

11.1

GENERAL

11.1.2

[Add] If requested by COMPANY for specific critical pump sealing seal applications, the seal MANUFACTURER shall provide data on the selected type and grade of the materials used for the seal faces and gaskets and on the materials supplied by the SUBSUPPLIER/MANUFACTURER. It is recognized that this information is not part of the normally supplied seal data and, as such, the contents and details shall be agreed upon by COMPANY and the seal MANUFACTURER.

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DGS-MU-017 Rev- 2 Dec 2013

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

APPENDIX 1

SEAL SELECTION PHILOSOPHY

FOLLOWING ARE THE GENERAL GUIDELINES FOR SEAL SELECTION GIVING MINIMUM CRITERIA. FINAL SEAL SELECTION SHALL BE THE JOINT RESPONSIBILITY OF THE PUMP VENDOR AND SEAL VENDOR

Sr No

Service

Pumping Temperature Range

API 682 Seal Code & Flush Plans Comments Category

Type

Arrange ment

Configuration

Primary Flush Plan

Secondary Flush Plan

1

Fresh water, condensate

0-80 °C

2

A

1

CW-FL

11

61M

2

Fresh water, condensate

81-100 °C

2

A

1

CW-FL

23

61M

3

Sea Water

0-80 °C

2

A

1

CW-FL

11

61M Note

4

Boiler Feed Water

80-290 °C

2

A

1

CW-FL

23

61M

5

Sour Water H2S >50 ppm <200 ppm

0-80 °C

2

A

1

CW-FL

11

61M

6

Sour Water H2S >200 ppm <500 ppm

7

8

Sour Water H2S >500 ppm <2000 ppm Sour Water H2S >2000 ppm

2

A

2

CW-CW

2

52

0-80 °C

2

A

3

CW-FB

2

53

note NACE requirement

0-80 °C

3

A

3

CW-FB

2

53

note NACE requirement

0-60 °C

2

A

1

CW-FL

11

62

Consider Plan 32

10

Oily Water Sump applications

VS4 Pumps

2

A

1

NC-FX

2

11

Storm Water Sump applications

VS4 Pumps

2

A

1

NC-FX

2

12

Sea Water Sump applications

VS4 Pumps

2

A

1

NC-FX

2

VS4 Pumps

2

A

1

NC-FX

2

VS4 Pumps

2

A

1

CW-BB

2

14

note NACE requirement

0-80 °C

Brine to max 60g/litre

Hydrocarbon Non Flashing Sump applications Hydrocarbon Flashing Sump applications

62 May be required, confirm metallurgy

note NACE requirement, consider Plan 11, alternate 2 CW-NC 11&75

9

13

Notes

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Packed Gland, Dry Running Contacting Seal Packed Gland, Dry Running Contacting Seal Packed Gland, Dry Running Contacting Seal

53

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Abu Dhabi Oil Refining Company

DGS-MU-017 Rev- 2 Dec 2013

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

15

Hydrocabon Non Flashing with H2S (low levels below 200 ppm)

2

A

1

CS-FX

2

16

Sea Water Vertical Lift

1

A

1

CW-FL

32

17

Cooling Water

2

A

1

CW-FL

11

0-80 °C

Clean Water flush 61M Check contaiminants and discuss with pump / seal vendor note check for hazardous liquid if yes use dual pressuirsed seal.

18

Process Water

0-80 °C

2

A

1

CW-FL

11

61M

19

Hydrocarbons - Non Flashing

-40 °C to -5 °C

2

A

2

CW-NC

11

72&75

20

Hydrocarbons - Non Flashing

-6 °C to 175 °C

2

A

1

CW-FL

11

61M

21

Hydrocarbons - Non Flashing

176 °C to 400 °C

2

C

3

CW-BB

2

53

22

Hydrocarbons - Non Flashing

to a max of 400 °C

3

C

3

CW-BB

2

53

23

Hydrocarbons - Flashing

-5 °C to 59 °C

2

A

2

CW-CS

11

76

24

Hydrocarbons - Flashing

60 °C to 175 °C

2

A

3

CW-BB

2 Note

53

Consider Plan 23

25

Hydrocarbons - Flashing

176 °C to 400°C

2

C

3

CW-BB

2 Note

53

Consider Plan 23

26

Hydrocarbons - Flashing

to a max of 400 °C

3

C

3

CW-BB

23

53

27

Hydrocarbons

Contaminated with H2S

28

Hydrocarbons

Contaminated with Benzene

Above auto ignition temperature

Above auto ignition temperature

as a minimum follow Sour Water with ppm H2S or hydrocarbon at operating temperature

2

A

3

CW-BB

2

53

Examples of Hydrocarbon Services

29

Naphtha

0-80 °C

2

A

1

CW-CS

11

76

30

Propane / Butane

0-80 °C

2

A

3

CW-FB

11

53

31

Crude Oil

0-80 °C

2

A

1

CW-FL

11

65

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Check with process for H2S or Benzene present

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DGS-MU-017 Rev- 2 Dec 2013

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

32

Crude Oil

>200 °C

33

Diesel Oil

34

Possibility of Coking

2

A

3

CW-FB

2

53

0-80 °C

2

A

1

CW-FL

11

61M

Kerosene

0-80 °C

2

A

1

CW-FL

11

61M

35

Molten Sulphur

127 °C

Horizontal

2

A

1

CW-FL

11

62

Steam Quench Consider also a Hydrodynamic Seal

36

Molten Sulphur

127 °C

VS4

-

-

-

-

-

-

Packed Gland

37

Corrosive Acid

0-80 °C

2

A

3

CW-FB

2

53

38

Sulphuric Acid

0-80 °C

2

A

1

CW-FL

11

61

39

Hydrofluoric Acid

0-80 °C

40

41

NAOH (Low concentrations) NAOH (High Concentrations)

Work with Pump Vendor / Seal Vendor

0-80 °C

2

A

1

CW-FL

11

62

0-80 °C

2

A

3

CW-FB

2

53

42

Benzene

0-80 °C

2

A

3

CW-BB

2

53

43

Amines

0-240 °C

2

A

3

CW-BB

2

53

44

Lean MEG

0-80 °C

2

A

3

CW-BB

2

53

45

Rich MEG

0-80 °C

2

A

3

CW-BB

2

53

46

FCC Slurries

up to 350 °C

Work with Pump Vendor / Seal Vendor

47

Viscous Applications

0-80 °C

Work with Pump Vendor / Seal Vendor

48

Dirty Service

0-80 °C

Work with Pump Vendor / Seal Vendor

Dual Non Pressurised Seals shall be supplied in the following services: Hazardous services Services where a five year operation cannot be achieved with a single seal

Dual Pressurised Seals shall be applied for the following services as a minimum Services where it is not permitted for the pumped liquid to enter the flare or atmosphere

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

If the available seal liquids are not compatible with the required seal conditions to obtain a 5 year life Hazardous and Toxic services Services containing H2S which upon seal failure result in an H2S leakage rate to atmosphere exceeding 1 g/s. Fluids with a SG less than 0.7 Operating temperatures higher than 200 °C Dry gas Seal Arrangements in pumps versus standard dual seal applications are subject to Company approval and shall be limited to A single liquid seal and a dry gas back up seal arrangement may be considered only for liquids not defined as Category 3 Dual pressurised dry gas seal arrangements with a pressurised Nitrogen barrier may only be considered for liquids that are not considered as hazardous, and have a maximum vapour pressure at pumping temperature of 1.05 bar(abs)

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

[ADD] ANNEX A

DGS-MU-017 Rev- 2 Dec 2013

RECOMMENDED SEAL SELECTION PROCEDURE (Part 1 of 2)

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682) [ADD] ANNEX A

DGS-MU-017 Rev- 2 Dec 2013

RECOMMENDED SEAL SELECTION PROCEDURE (Part 2 of 2)

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

[ADD] ANNEX A, SHEET 10 OF 10, (SI UNITS, PAGE 102) BARRIER/BUFFER FLUID SELECTION CRITERIA In addition the following shall be required for barrier liquid for pressurized dual seals: 1)

The barrier liquid shall be fully compatible with the pumped liquid (it is acceptable if it were to leak into the pumped liquid). The barrier liquid shall be suitable for leakage into the atmosphere and shall not create a hazardous situation or be considered environmentally unacceptable.

2)

The barrier liquid shall be able to withstand the maximum and minimum pumping temperature without decomposing or forming solids and/or corrosive/erosive components. It shall have an adequate viscosity at the minimum and maximum pumping temperature.

3)

The barrier liquid shall be fully compatible with all materials used in the seals and the seal piping and piping components.

4)

The barrier liquid shall provide adequate lubrication to the seal faces in order to ensure continuous pump operation for at least five years.

For unpressurized or low pressure dual seals the following shall be required for the selection of the buffer liquid: 1)

The buffer liquid shall be fully compatible with the pumped liquid. The barrier liquid shall be suitable for leakage into the atmosphere and shall not create a hazardous situation or be considered environmentally unacceptable.

2)

The buffer liquid shall be able to withstand the maximum and minimum pumping temperature without decomposing or forming solids and/or corrosive/erosive components. It shall have an adequate viscosity at the minimum and maximum pumping temperature.

3)

The buffer liquid shall be fully compatible with all materials used in the seals and the seal piping and piping components.

4)

The buffer liquid shall provide adequate lubrication to the seal faces in order to ensure continuous operating of at least five years. The liquid shall be checked for its suitability as a buffer fluid when it is saturated with the pumped liquid.

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

[MODIFY] ANNEX G.19

API 682 plan 61 modified

Drain connection shall be fitted with a stub pipe. If the seal leaks, fluid will escape past the throttle bush and cover the pump and surrounding area with fluid. By fitting the drainpipe, leakage will be directed to the base plate and a visual indication of leakage will also be given.

[MODIFY] ANNEX G.23

API 682 plan 72 modified

Test connection and test kit to check the integrity of the containment seal to be provided.

[MODIFY] ANNEX G.25

API 682 plan 75 modified

Test connection and test kit to check the integrity of the containment seal to be provided. [MODIFY] ANNEX G.26

API 682 plan 76 modified

Test connection and test kit shall be provided.

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

[ADD] ANNEX G.32

API 682 PLAN 53 MODIFIED, TYPE 1 WITH AIR FIN TUBE (NATURAL CONVECTION) OR WATER COOLING

NOTE: Annex G.32 shall be used for each seal on between bearing (BB) type pumps.

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

[ADD] ANNEX G.33

API 682 PLAN 53 MODIFIED, TYPE 1 WITH AIR FIN TUBE (NATURAL CIRCULATION) OR WATER COOLING FOR BETWEEN BEARINGS PUMP

NOTE: Delete this Annex G.33 Annex G.32 shall be used for each seal on between bearing (BB) type pumps.

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

[ADD] ANNEX G.34

API 682 PLAN 53 MODIFIED, TYPE 2 WITH AIR FIN TUBE (NATURAL CIRCULATION) OR WATER COOLING

NOTE: Delete this Annex G.34 Annex G.32 shall be used for each seal on between bearing (BB) type pumps.

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SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

[ADD] ANNEX G.35

API 682 PLAN 54 MODIFIED

Non Return Valve NOTE: Supply pumps are provided by others

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

[ADD] ANNEX G.36

API 682 PLAN 52

Takreer DGS-MU-017 Rev-2 Dec 2013

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

[ADD] ANNEX G.37

MAKE-UP SYSTEM FOR API PLAN 53 Modified AND/OR 52 SEAL SYSTEMS

RESERVOIR RECIRCULATING PUMP

Liters

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

ADDENDUM SHEET All revisions to this DGS subsequent to the issue of Rev Zero shall be recorded in this addendum sheet and shall be incorporated into the DGS in the next revision. Date June 2009

Proposed Revision

Remarks

PART II AMENDMENTS / SUPPLEMENTS TO API 682 In Section # 1.0:

Incorporated in Revision 1

Amend second sentence of second paragraph as: The applications addressed in this specification cover sealing duties for pumps with a working temperature range of -40 to +400 °C and a maximum allowable working pressure up to 42 bar (abs). It covers seals for pump shaft diameters from 20 mm to 110 mm. Seal applications outside these boundaries are subject to the same design and configuration, shall be termed as “Engineered Seals” and shall require COMPANY's approval. In Section # 2.0: Add following: American Standards: API 682

Shaft Sealing Systems for Centrifugal and Rotary Pumps

British Standards: BS EN 10204 Metallic Materials – Types of Inspection Documents In Clause # 1.4: Add “[Add] Refer to Appendix 1 – Seal Selection Philosophy for general guidelines on seal selection.” In Clause # 4.2.3: Delete this Clause in totality “[New] Annex B provides specific application details and material requirements for several pumped fluid applications. The seal MANUFACTURER may propose alternatives to these requirements, subject to approval of COMPANY.”

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

In Clause # 6.1.1.6: Replace this Clause “[Replace the last sentence by] All components, including the seal and flush systems, shall be designed for the Maximum Allowable Case Working Pressure (MACWP) of the pump. The seal’s dynamic pressure rating at the specified service conditions shall not be less than the maximum discharge pressure of the pump.” With “[Replace the last sentence by] The static sealing pressure rating (SSPR) of mechanical seals shall be greater than or equal to the maximum static sealing pressure (MSSP), which shall be calculated as indicated below. For Arrangement 1 seals, the MSSP of each seal shall be equal to the maximum static seal chamber pressure that can occur in the pump. Unless otherwise specified, this shall be the shut-off pressure of the pump at maximum suction pressure. For Arrangement 2 seals, the MSSP of both the inner and outer seal shall be equal to the maximum static seal chamber pressure that can occur in the pump. Unless otherwise specified, this shall be the shut-off pressure of the pump at maximum suction pressure. For Arrangement 3 seals, the MSSP of the outer seal shall be equal to the maximum static seal chamber pressure that can occur in the pump. Unless otherwise specified, this shall be the greater of 1) shut-off pressure of the pump at maximum suction pressure or 2) the maximum barrier fluid pressure. The MSSP of the inner seal shall be the greater of 1) differential between the maximum barrier fluid pressure and the minimum seal chamber pressure or 2) the maximum differential between maximum seal barrier fluid pressure and atmospheric pressure.” In Clause # 4.2.3: Delete this Clause in totality “[Add] The Maximum Static Sealing Pressure (MSSP) OF Mechanical Seals shall be at least as indicated below: •

For single seals and dual seals in tandem, the MSSP of each seal shall be at least equal to the maximum static pump seal chamber pressure. Unless otherwise specified, this shall be the shut off pressure of the pump at maximum suction pressure.

•

For dual seals in back to back or face to face arrangement, the MSSP of the outer seal shall be at least equal to the maximum static seal chamber pressure in the pump. Unless otherwise specified, this shall be the shut off pressure of the pump at maximum suction pressure.”

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

Add new Clause # 8.1.3: “[Replace with:] Unless specified otherwise, the seal Vendor shall supply all flush coolers and instrumentation associated with the flush plans being applied. Unless specified otherwise, the pump Vendor shall supply and fit all orifices, interconnecting pipework and other items associated with the flush plans being applied. All auxiliary piping systems, except Plans 52 and 53 shall be mounted within the confines of the associated pump’s baseplate area. Plan 52 and Plan 53 systems may be mounted either on or off the pump baseplate, as specified on the datasheet. If mounted on the baseplate then the interconnecting pipework (and associated drain and vent) shall be supplied and fitted by the pump Vendor. If mounted off the baseplate then interconnecting pipework (and associated drain and vent) shall be supplied and installed by the CONTRACTOR, unless specified otherwise.” In Clause # 8.1.8: Add in second paragraph “All fabricated joints in seal system piping shall be full penetration butt welded and the weld root shall be made by gas tungsten arc welding (GTAW).” In Clause # 8.2.1: Add “This Specification provides replacement piping and instrumentation schematics for G.14 (Plan 52), G.16 (Plan 53B), and G.18 (Plan 54).” Add new Clause # 8.4.1: “[Replace with] Details of Cooling Water System are as given in Basic Engineering and Design Data.”

In Clause # 8.5.3.1: Add “Coolers can be either water-cooled or air-cooled.” Add new Clause # 8.5.4.1: “[Add] Make up barrier fluid connections shall be provided so that each connection is colour coded and unique to a barrier fluid. The requirement is to minimize the risk of using an incorrect barrier fluid for topping up.” Takreer DGS-MU-017 Rev-2 Dec 2013

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

In Clause # 8.5.4.2: In Item # a), Replace “pump” With “seal” Add following new Items: “d)

[Add] In order to minimize the pressure drop within the system, pipework shall be not less than 3/4 inch diameter.

f)

[Add] A means of filling and re-charging the seal system shall be provided. Refer to Annex G.37 for details of scope. Seal vendors are to review the pipework and fittings used in the construction of the seal support piping systems and confirm that the circulating device recommended can achieve the required flow rates with the proposed seal buffer fluid.”

Add new Clause # 8.5.4.4.11: “[New] The rating of the reservoir shall be at least equal to the MAWP of the pump casing.” Add new Clause # 8.5.4.5g: “[New] The rating of the reservoir shall be at least equal to the MAWP of the pump casing.” In Clause # 8.5.4.7: Delete from first sentence “and G.33” Add “For between bearing pumps, each seal shall be individually supported, as shown in Annex G. 32. (i.e. Annex G33 shall not be used.)” Add new Clause # 8.6.2.2: “[Add] Seal vendors shall provide the performance curve for head versus flow for the recommended circulating device.” Add new Clause # 8.6.5.2e: “Replace “Switch”, with “Transmitter””

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

Add new Clause # 8.6.5.3: “Replace “Switch”, with “Transmitter”” Add new Clause # 8.6.5.4: “[Add] All containment seal systems shall be provided with a test connection and a testing kit. The testing kit scope shall be as defined in Figure 1.”

Add new Clause # 8.6.6.1: “[Add] Barrier/buffer gas system connections shall be routed so that they are accessible to operators standing at grade level alongside the seal system.” Add new Clause # 8.6.6.2: “Replace “Switch”, with “Transmitter”” In Section # 9.0: Add “Wherever switches are referred to, transmitters are to be supplied. All controls and instruments shall be located no higher than 1.8 m above grade, in order to permit easy visibility by the operators, as well as accessibility for tests, adjustments, and maintenance. Where it is envisaged that ladders will be required, the vendor shall supply a safe working platform with stairs to reach the working platform.”

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

Add new Appendix: “APPENDIX 1 – SEAL SELECTION PHILOSOPHY” In Annex A: Replace “3 years” With “5 years” Delete “Annex B – Typical Materials Standards for Seal Chambers and Mechanical Seal Components” In Annex G: Add “[MODIFY] ANNEX G.19

API 682 plan 61 modified

Drain connection shall be fitted with a stub pipe. If the seal leaks, fluid will escape past the throttle bush and cover the pump and surrounding area with fluid. By fitting the drainpipe, leakage will be directed to the base plate and a visual indication of leakage will also be given. [MODIFY] ANNEX G.23

API 682 plan 72 modified

Test connection and test kit to check the integrity of the containment seal to be provided. [MODIFY] ANNEX G.25

API 682 plan 75 modified

A test connection and test kit to check the integrity of the containment seal to be provided. [MODIFY] ANNEX G.26

API 682 plan 76 modified

A test connection and test kit SHALL be provided.”

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

In Annex G.32: Delete “Optional” from TI Add “Note: Annex G.32 shall be used for each seal on between bearing (BB) type pumps.” In Annex G.33: Add “Note: Delete this Annex G.33 Annex G.32 shall be used for each seal on between bearing (BB) type pumps.” In Annex G.34: Add “Note: Delete this Annex G.34 Annex G.32 shall be used for each seal on between bearing (BB) type pumps.” In Annex G.36: Delete “Optional” from TI Add “High” to LA

Dec 2013

Add the following Clause No. 8.5.4.3 (b) to Clause No. Incorporated in 8.5.4.3 (Accumulator sizing): revision 2 Clause No. 8.5.4.3 (b): “the accumulator shall be equipped with a pressure gauge to monitor the Nitrogen precharge pressure.” Clause No. 1.0 Scope Add the following sentence to the end of 2nd paragraph of Clause No. 1.0: “The seal Vendor shall supply references of seals in similar services.”

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Abu Dhabi Oil Refining Company

SHAFT SEALING SYSTEMS FOR CENTRIFUGAL & ROTARY PUMPS (AMENDMENTS / SUPPLEMENT TO API 682)

DGS-MU-017 Rev- 2 Dec 2013

Clause No. 3.0 Definitions Add following new definitions: 3.82 Plan 54 (Plant wide): Is a plan 54 where the external seal flush is supplied from plant-wide system engineered and supplied by the buyer. 3.83 Plan 54 (Stand-alone): Is a plan 54 where the external seal flush is supplied from a Stand-alone seal support console engineered and supplied by the seal supplier. There will be one such console per pump. The external flush fluid shall have dual pumps, one running and one stand by.

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