Previous Issue: 6 September 2008 Next Planned Update: 18 January 2015 Page 1 of 41 Primary contact: Anizi, Salamah Salem on 966-3-8760203
Copyright©Saudi Aramco 2010. All rights reserved.
Materials System Specification
32-SAMSS-021 18 January 2010
Manufacture of Industrial Boilers
Heat Transfer Equipment Standards Committee Members Anizi, Salamah Salem, Chairman Bagawi, Jamil Jarallah, Vice Chairman Anezi, Mohammed Ali Dossary, Musfir Abdullah Fernandez, Gabriel Thomas Gahtani, Moraya Saif Guthami, Mohammed Mohsen Hamam, Ibrahim Hassan Harbi, Abdullah Mohammed Saeed Mansour, Khalid Mohammad Naffaa, Mahmoud Youniss Rumaih, Abdullah Mohammad
Saudi Aramco DeskTop Standards Table of Contents 1 Scope............................................................. 2 2 Conflicts and Deviations................................. 2 3 References..................................................... 2 4 Definitions and Abbreviations......................... 5 5 Responsibilities............................................... 6 6 Proposals........................................................ 6 7 Design............................................................ 8 8 Sootblowers.................................................. 18 9 Air Preheaters............................................... 21 10 Economizers................................................. 21 11 Firing System Equipment............................. 22 12 Forced Draft Fans........................................ 26 13 Ductwork...................................................... 28 14 Stacks........................................................... 29 15 Insulation and Refractories.......................... 29
Document Responsibility: Heat Transfer Equipment 32-SAMSS-021
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Next Planned Update: 18 January 2015 Manufacture of Industrial Boilers
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Table of Contents (cont'd)
16 Noise Attenuation......................................... 30 17 Connections, Boiler Trim and Instruments... 30 18 Burner Management Systems...................... 34 19 Painting........................................................ 34 20 Fabrication.................................................... 34 21 Nondestructive Testing................................. 35 22 Postweld Heat Treatment............................. 36 23 Inspection and Equipment Testing............... 36 24 Nameplates and Stampings......................... 38 25 Preparation for Shipment............................. 38 26 Drawings, Calculations and Data................. 40 27 Life Cycle Cost Evaluation........................... 40
1 Scope
1.1 This specification covers the minimum mandatory requirements for the
manufacture of industrial type watertube fire, (herein referred to as boilers), that
are fueled by either oil, or gas.
1.2 This specification includes requirements for the thermal sizing, mechanical
design, shop fabrication, field fabrication, installation, and testing of boilers.
1.3 The requirements in this specification are in addition to and supplement the
requirements of the Boiler and Pressure Vessel Code, ASME SEC I, (herein
referred to as the Code).
2 Conflicts and Deviations
2.1 Any conflicts between this specification and other applicable Saudi Aramco
Materials Systems Specifications (SAMSSs), Saudi Aramco Engineering
Standards (SAESs), Standard Drawings (SASDs), or industry standards, codes,
and forms shall be resolved in writing by the Company or Buyer Representative
through the Manager, Consulting Services Department of Saudi Aramco,
Dhahran.
2.2 Direct all requests to deviate from this specification in writing to the Company or
Buyer Representative, who shall follow internal company procedure SAEP-302
and forward such requests to the Manager, Consulting Services Department of
Saudi Aramco, Dhahran.
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Next Planned Update: 18 January 2015 Manufacture of Industrial Boilers
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3 References
Materials or equipment supplied to this specification shall comply with the latest edition
of the references listed below, unless otherwise noted.
3.1 Saudi Aramco References
Saudi Aramco Engineering Procedures
SAEP-302 Instructions for Obtaining a Waiver of a
Mandatory Saudi Aramco Engineering
Requirement
SAEP-341 Equipment Life Cycle Cost Procedure
Saudi Aramco Engineering Standards
SAES-A-004 Pressure Testing
SAES-A-005 Safety Instruction Sheet
SAES-A-102 Air Pollutant Emission Source Control
SAES-A-112 Meteorological and Seismic Design Data
SAES-B-054 Access, Egress, and Material Handling for Plant
Facilities
SAES-H-001 Selection Requirements for Industrial Coatings
SAES-H-100 Painting Requirements for Industrial Facilities
SAES-H-101 Approved Protective Coating Systems
SAES-J-602 Burner Management, Combustion, and Waterside
Control Systems for Watertube Boilers
SAES-N-001 Basic Criteria, External Insulation
SAES-N-100 Refractory Systems
SAES-N-110 Installation Requirements - Castable Refractory
SAES-N-130 Installation Requirements - Fireclay Bricks
SAES-N-140 Installation Requirements - Refractory Ceramic
Fiber
Saudi Aramco Materials System Specifications
17-SAMSS-503 NEMA Frame Motors
32-SAMSS-009 General Purpose Steam Turbines
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34-SAMSS-611 Safety Relief Valves, Conventional and Balanced
Types
34-SAMSS-617 Fire Monitoring Systems
34-SAMSS-619 Flame Monitoring and Burner Management
Systems
34-SAMSS-830 Programmable Logic Controllers
Saudi Aramco Inspection Requirements
Form 175-321300 Boiler: Power; Water Tube
Saudi Aramco Forms and Data Sheets
Form 7305-ENG Equipment Noise Data Sheet
Form 9570-ENG Safety Instruction Sheet
Form SDS-ME 9550 Watertube Boiler Smart Data Sheets
Form SA-F-002 Pre-commissioning Boilers
Form NMR-7913 Non-material Requirements for Industrial
Watertube Boilers
3.2 Industry Codes and Standards
American Institute of Steel Construction
AISC 325 Steel Construction Manual
AISC 326 Detailing for Steel Construction
Air Movement and Control Association, Inc.
AMCA 210 Laboratory Methods of Testing Fans for Rating
American Society of Civil Engineers
ASCE 7 Minimum Design Loads for Buildings and Other
Structures
American Society of Mechanical Engineers
ASME PTC 4 Steam Generating Units
ASME SEC I Power Boilers
ASME SEC II Material, Part D
ASME SEC V Nondestructive Examination
ASME SEC VIII Rules for Construction of Pressure Vessels
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ASME SEC IX Welding and Brazing Qualifications
American Society for Testing and Materials
ASTM A20 General Requirement for Steel Plates for Pressure
Vessels
ASTM A435 Straight-Beam Ultrasonic Examination of Steel
Plate
ASTM D1066 Standard Practice for Sampling Steam
National Fire Protection Association
NFPA 85 Boiler and Combustion System Hazard Code
4 Definitions and Abbreviations
Definitions
Boiler: Within the scope of ASME SEC I, Power Boilers, and this specification.
Boiler Power Piping: Within the scope of ASME SEC I, Power Boilers, Figures PG-
58.3.1 and PG-58.3.2, and this specification.
Boiler Supplier: The Company responsible for manufacturing boilers in accordance
with the requirements of this specification.
Engineering Company: The company responsible for specifying the design
requirements for boilers on the data sheet
EPRS: Effective projected radiant surface, is the projected area of the walls, roof, and
floor of the furnace enclosure, including the furnace exit area.
Furnace Volume: The cubic contents of space provided for the combustion of fuels.
Heating Surface: The flat projected area, excluding refractory covered surfaces.
Saudi Aramco Engineer: The Supervisor of the Heat Transfer Systems Unit,
Consulting Services Department, Dhahran.
Saudi Aramco Inspector: The person or company authorized by the Saudi Aramco
Inspection Department to inspect boilers to the requirements of this specification.
Flame Impingement: Direct contact between a flame and a tube.
ADCT: Acid Dew point Calculated Temperature. It shall be calculated on the basis of
5% conversion of sulfur dioxide to sulfur trioxide.
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Abbreviations (Levels and Rating)
HHWL: High-High Water Level ESD
HWL: High Water Level Alarm
LLWL: Low-Low Water Level ESD
LWL: Low Water Level Alarm
MCR: Maximum Continuous Rating
NLL: Normal Water Level
5 Responsibilities
5.1 The Boiler Supplier is responsible for the thermal design, mechanical design,
(Code and structural calculations), supply of all materials, fabrication,
inspection, testing, and preparation for shipment, in accordance with the Code,
the completed data sheet and this specification.
5.2 The Engineering Company is responsible for specifying the design requirements
for boilers, as noted on the data sheet. The balance of boiler instrumentation in
accordance with SAES-J-602, for both field and control room instruments
including the following shall be supplied by the Boiler Supplier:
1) Combustion and feedwater regulatory controls
2) Burner management systems
3) Steam drum level indication and shutdown instruments
4) Sootblower controls
5) Combustion and waterside analyzers
6) Desuperheater controls
7) Flue gas analyzers (CO, NOx, O2)
8) All instrument connections
9) Combustion air flow elements
10) Connections for flame monitors, including: scanners, receivers and
mountings for junction boxes
11) Soot Blower hardware
12) Thermowells
6 Proposals
6.1 General
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6.1.1 The Boiler Supplier proposal shall be based on details for individual
boilers as outlined on the data sheet.
6.1.2 The Boiler Supplier may offer an alternative design, but must quote on
the base inquiry documents.
6.1.3 The Boiler Supplier proposal shall include a detailed description of any
exception to the requirements of this specification and referenced
industry standards herein.
6.1.4 The Boiler Supplier shall advise the Saudi Aramco Engineer when Boiler
Supplier has any part of a stress analysis executed by a third party.
6.1.5 No proof testing shall be permitted unless specifically approved by the
Saudi Aramco Engineer.
6.1.6 Application of Code Cases to the Supplier of boilers requires approval of
the Saudi Aramco Engineer.
6.2 Detailed Requirements
The Boiler Supplier is to supply the following information with the proposal.
This information is necessary and will be used to complete the technical
evaluation of the quotation. The quotation will be technically unacceptable if
any of the information required is not included.
1) A completed data sheet.
2) A complete boiler supplier performance sheet including heat libration
calculation for furnace sizing at 25%, 50%, 75%, and 100% MCR.
3) Minimum and average Circulation ratios for all circuit diagrams.
4) A list of users operating boilers of the same design and under similar
operating conditions.
5) Sizes of observation ports.
6) The pressure and flowrate required for desuperheater spraywater.
7) Dimensional drawing(s) showing typical internals of drums, materials of
drums and headers, inside diameters, drum and header thicknesses, water
and steam circuit arrangements, furnace configuration, burner locations,
flue gas and air duct arrangements.
8) Typical cross-sectional sketch of steam drums showing the location of
internals, all water levels, and the highest downcomer. The sketch shall
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also show the useful water volume in the steam drum below the NWL,
LWL, and LLWL ESD.
9) Locations of access doors, observation ports, platforms, stairways, and
ladders on a general arrangement type drawing.
10) Acid dewpoint temperature against acid dew point corrosion.
11) Maximum Flame profile dimensions for all specified fuels or combination
of fuels
12) Typical Burner general arrangement drawings with a turn down ratio.
13) Maximum Atomizing steam flow and steam/oil pressure differential
requirements.
14) A completed noise data sheet (Form 7305-ENG) with a detailed
description of acoustical design.
6.3 Performance Guarantees
The following shall be guaranteed for the length of the warranty period specified
in the purchase order or contract documents:
1) Superheater outlet pressure and temperature downstream of the non-return
valve as specified on the data sheet operating between 25% and 100% MCR.
2) Efficiency at 25%, 50%, 75% and 100% MCR with steam conditions and
fuels fired as specified.
3) Unless otherwise specified on the data sheet, a maximum concentration of
100 ppb (parts per billion) total dissolved solids (TDS) and 20 ppb each of
sodium and silica in saturated steam at any load within a boiler's controlled
range when firing any fuel or combination of fuels specified on the data
sheet, provided that ASME BFW quality is met.
4) A controlled flame at all loads to comply with definition of flame
impingement.
5) Stable flame within operation of the boiler from start-up to 100% MCR.
when firing any of the fuels specified on the data sheet.
6) Maximum % load achievable with stable flame- when firing any fuel or
combination of fuels specified and with one burner out of service.
7) Smooth operation in either direction with a stable flame over the complete
operating range with a rate of change in steam demand of 10% MCR per
minute, and without actuating of the LLWL ESD or HHWL ESD.
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8) Flue gas emission levels at operating range of 25% to 100% MCR.
9) Sound levels at normal operating conditions.
7 Design
7.1 General
7.1.1 The design of boilers, boiler piping, and associated equipment shall
conform to the Code, and the completed data sheet.
7.1.2 Equipment and components of standard manufacture shall be provided
to ensure the availability of spare parts. Components need not be
products of the Boiler Supplier, however, the Boiler Supplier shall
assume full responsibility for all components supplied regardless of
their source.
7.1.3 The design of boilers auxiliary components located outdoors shall be
suitable for continuous operation at the summer design temperature for
the site, as specified in SAES-A-112.
7.1.4 Regardless of climatic conditions, all external surfaces shall be self-
draining and protected against corrosion. Open covers (roof and sides
only) shall be provided over firing aisles.
7.1.5 Boilers shall be designed to operate continuously in the automatic
control mode, but with manual control override capabilities, under all
conditions specified on the data sheets.
7.1.6 Boilers and auxiliaries, including control instrumentation, shall be
designed for continuous operation during electrical power outages
through an uninterrupted power supply system (to be provided by
others). The Boiler Manufacturer shall submit an estimate of the
electrical power required.
7.1.7 Boiler auxiliaries shall be capable of sustained operation in automatic
control mode between 25% and 100% MCR for a minimum period of
two years between shutdowns required for the complete testing and
inspection (T&I) of a boiler.
7.1.8 Boilers and auxiliaries shall be capable of accommodating a rate of
change of 10% MCR per minute over the control range of the boiler,
for both an increasing and decreasing steam demand, without causing a
level shutdown or water carryover during the transient condition.
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7.1.9 Circulation calculations at100% MCR shall be prepared and submitted
by the Boiler Supplier for review.
7.1.10 For shipping shop-assembled units (packaged boilers), the boiler,
burners, all necessary appurtenances, and auxiliary equipment (except
fans, drivers, air preheater, economizer, panels for local controls and
burner management systems) shall be mounted on an integral steel
base to provide a complete, self-contained steam generating unit. All
vibration-sensitive equipment shall be shock-mounted.
7.1.11 Furnaces and gas passes shall be designed to prevent dead-ended or
poorly ventilated pockets where combustibles might accumulate and
cause an explosion upon ignition.
7.1.12 Gas passes through furnaces, superheaters and convective heat transfer
surfaces, as well as air and flue gas ducts, shall be designed and
arranged to prevent vibrations from vortex shedding, sootblower
impact loadings, and turbulence. Boiler Supplier shall submit vibration
calculations including flow induced and acoustical vibration.
7.1.13 All outside water walls and furnace division walls shall be of the
membrane wall design.
7.1.14 Gaps between tubes shall be proportional to the tube OD, and shall not
exceed 25 mm in the firebox. Fins (strips) shall be at least 6 mm thick.
Tangent tube welded walls are not acceptable. Any deviation in fin
dimensions shall be identified in the proposal and shall be supported by
fin temperature gradient and stress calculations in the design phase.
7.1.15 All water, steam and fuel piping shall extend 1.0 m beyond the battery
limits of the boiler, exact locations shall be specified by the
Engineering Company.
7.1.16 Space and access shall be provided for the inspection, cleaning,
removal, and maintenance of tube bundles, headers, retractable burner
parts, valves, pumps, fans, turbines, and motor drivers. The boiler
floor casing shall be a minimum of 1 m above grade.
7.1.17 Guards or personal protection type insulation shall be provided around
operating areas where exposed surfaces are hotter than 65°C.
7.1.18 Facilities shall be provided for the complete draining of all water from
the fire side of boiler units after washing. Drains openings shall be a
minimum of 75 mm diameter and be sealed against overheating and
escape of flue gases.
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7.1.19 Enclosures for instrumentation and electrical equipment shall be
selected for the area classification specified on the data sheet.
7.2 Corrosion Allowances
Pressure components other than tubes shall have a minimum corrosion
allowance of 1.0 mm.
7.3 Furnaces
7.3.1 The dimensions and design of furnaces shall be such that complete
combustion of fuels take place within the furnace limits without flame
impingement on sidewalls, roofs, and front walls.
7.3.2 Based on the highest heating values of the fuels, the maximum heat
release at 100% MCR in a furnace of watertube boiler type shall be
designed within the following parameters:
1) The net heat liberation within a furnace volume shall not exceed
620-kW/ m³ (60,000 Btu/hr-ft³) for liquid fuels, 15 API gravity
and heavier, or 820-kW/m³ (80,000 Btu/hr-ft³) for gaseous fuels
and liquid fuels, lighter than 15 API gravity.
2) The net heat absorption rate shall not exceed 470 kW/m²
(150,000 Btu/hr-ft²) of the effective projected radiant surface
(EPRS) for all fuels.
3) Credit for tile-covered floor tubes shall not exceed 10% of the
projected floor area.
7.3.3 Self-closing observation ports having minimum dimensions of 50 x
100 mm or a 100 mm in diameter shall be provided. Ports shall be of
the guillotine design and shall be air-purged for self-cleaning and
cooling.
7.3.4 The number, size, and location of ports shall ensure the visibility of all
burner tips, furnace rear walls, side walls, furnace exit areas, and
furnace roofs.
7.4 Superheaters
7.4.1 Superheaters shall be located such that inlet tubes are not located in
regions of highest flue gas temperatures.
7.4.2 Superheaters may be an all-welded convection or radiant-convection,
located outside furnaces. When located within direct view of burners a
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minimum of two rows of staggered screen tubes shall be provided
between the superheater and furnace.
7.4.3 Flow equalization through superheater tubes shall be achieved by the
sizing of tubes, inlet header, and outlet headers. Tube inlet restrictions,
including swaging, is not permitted.
7.4.4 Desuperheater water flow should not exceed 5% of steam flow. In
case where more percentage is required the steam temperature down
stream the attemperator shall be higher by 10C above saturation
temperature.
7.4.5 Superheater elements shall be located and supported to prevent
vibration, sagging, and misalignment.
7.4.6 Superheater headers shall be located outside gas spaces.
Superheater interconnecting piping shall be provided with,
thermowell,and temperature transmitter. Superheater outlet piping
shall be provided with connections for safety valves and startup vent,
test gage, pressure transmitter, thermowell, temperature transmitter and
pressure gage connections. All superheater outlet piping connections
shall be located upstream ofthe start up vent.
7.4.7 The startup vent and its discharge stack shall be sized for not less than
25% MCR steam flow, and shall be provided with a silencer. Silencers
shall be provided with suitable drains for condensate removal, and
piped to sewer.
7.4.8 Superheater tubes shall be arranged so that sootblowers can effectively
remove soot from the outside surfaces of tubes. Superheater tubes
shall be arranged to prevent soot bridging and plugging gas passages.
7.5 Desuperheaters
7.5.1 Desuperheaters shall be of the water-spray design.
7.5.2 A spray-type desuperheater mixing chamber with an alloy steel liner
shall be provided.
7.6 Steam Generating and Superheater Tubes
7.6.1 All tubes shall be seamless steel or electric resistance welded (ERW)
steel. ERW tubes shall not be used in superheaters.
7.6.2 All tubes shall have a minimum outside diameter of 38 mm.
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7.6.3 Tube material shall be selected based on the highest anticipated metal
temperatures and flue gas composition.
7.6.4 Tube configurations shall allow the free natural circulation of water
and steam, in the proper direction, at all loads, and installed to allow
complete draining of each tube.
7.6.5 Tubes to boiler drums shall be attached by rolling for drums.
7.6.6 All vertical tubes shall be supported or guided, or both, to prevent
bowing and vibration, and to permit expansion.
7.6.7 The minimum wall thicknesses of tubes shall be: 4 mm for 3" OD
tubes and 3 mm for 2"OD tubes and below.
7.6.8 Exposed portions of drums and headers shall be covered with
firebricks or castable refractory.
7.6.9 Horizontal (less than 3 degrees) tubes located in furnace floors shall be
covered by firebricks, 50 mm minimum thickness.
7.7 Baffles
7.7.1 The use of baffles shall be minimized and refractory baffles are
prohibited.
7.7.2 Baffles shall be manufactured of heat-resistant alloy steel and capable
of withstanding gas temperatures and sulfur content under maximum
load conditions.
7.7.3 Baffle walls shall be designed with gas-tight design to prevent gas
bypassing.
7.7.4 All baffles shall be accessible for inspection and repair without
dismantling of casings.
7.8 Drums and Headers
7.8.1 Design pressure shall be at least 5% or 100 kPa (15 psig), above
maximum operating drum pressure, whichever is the greater.
7.8.2 Downcomers and internals shall be designed to ensure positive
circulation under all loads.
7.8.3 Steam drum sizing shall satisfy the following criteria:
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1) The steam space shall be adequately sized to contain steam
separation equipment necessary to attain the guaranteed steam
purity specified throughout the control range.
2) The water holding capacity between the LWL and LLWL shall
be sufficient to sustain one minute evaporation at MCR with no
feedwater flow.
3) The LLWL shall be located not less than 50 mm above the top of
the highest downcomer.
4) A rise in water level (swell) above the NWL resulting from the
requirements specified in paragraph 7.1.9 shall not cause a
carryover or actuation of the HWL alarm.
5) A fall in water level (shrinkage) below the NWL resulting from
the requirements specified in paragraph 7.1.9 shall not cause the
actuation of the LWL alarm.
7.8.4 When intermediate headers are required within a circulating circuit,
restrictions to boiler circulation caused by headers shall be considered.
Headers shall be protected from direct heat or radiant heat from flue
gases.
7.8.5 Drum connections shall be a minimum of ¾ inch NPS.
7.8.6 The wall thickness of connections up to and including 2 inch NPS shall
be schedule 160 minimum.
7.8.7 Pipe sizes of 1¼ inch, 5 inch, and 7 inch NPS shall not be used.
7.8.8 A manway shall be provided at both ends of steam and water drums
and provided with hinged covers.
7.8.9 Header handholes shall be provided.
7.8.10 Drum connections shall be in accordance with Table 1.
Table 1 – Drum Connections
Service Description Design Pressure Type of
End-Connection
Steam outlets All Welded
Safety valves All Flanged
Chemical feed with thermal sleeve
All Flanged
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Service Description Design Pressure Type of
End-Connection
Feedwater inlet with thermal sleeve
All Welded
Water columns, lower connection with thermal sleeve
Under 4.48 MPa (650 psig) 4.48 MPa (650 psi) and above
Welded
Steam pressure gages Under 4.48 MPa (650 psig) 4.48 MPa (650 psi) and above
Flanged Welded
Vents Under 4.48 MPa (650 psig) 4.48 MPa (650 psi) and above
Flanged Welded
Sampling connections Under 4.48 MPa (650 psig) 4.48 MPa (650 psi) and above
Flanged Welded
Continuous and intermittent blowdown
Under 4.48 MPa (650 psig) 4.48 MPa (650 psi) and above
Welded
7.8.11 The facings of flanged connections shall be raised face type.
7.8.12 Steam and water drums shall be welded, postweld heat treated, and
100% radiographically tested in accordance with the Code.
7.8.13 Headers shall be constructed of seamless steel pipe.
7.8.14 Drums with wall thicknesses 50 mm and thicker shall have nozzle
connections as follows:
1) Connections 6 inch NPS and larger per Figures PW-16.1 (q-1),
(q-2), (q-3), or (q-4 ). [100% radiography test to be guaranteed
for (a,) (b), (c), (g), or (h)]
2) Connections 4 inch and less as per (1) above or Figure PW-16.1
(a), (b), (c), (g), or (h)
7.9 Steam Drum Internals
7.9.1 Steam drum internals shall consist of equipment for steam separation,
feedwater distribution, chemical feed distribution, and blowdown.
7.9.2 Steam separation equipment shall consist of centrifugal separators for
boilers above 20 bar operating pressure followed by dryers section
designed to meet the purity of steam specified on the data sheet.
7.9.3 Proposals for other types of steam separation equipment must be
included in the Boiler Manufacturer's proposal and must be
substantiated with test results from commercial units that the steam
purity entering the superheater will not exceed those specified on the
data sheet.
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7.9.4 All internals shall be designed such that they can be removed without
cutting.
7.9.5 The design of chemical feed distribution piping shall comply with the
following:
1) Be extended through steam drums and be of sufficient length to
ensure proper mixing of chemicals
2) Be perforated
3) Closed at the far end with a threaded cap
4) Provided with a thermal sleeve
5) Located in the steam drum to avoid short-circuiting of chemicals
into the continuous blowdown collection system.
7.9.6 Boiler feedwater distribution piping shall be provided with a thermal
sleeve and be extended through the steam drum to assure proper
mixing of the feedwater with the saturated recirculated water so that
thermal shock is avoided.
7.9.7 The design of continuous blowdown internal piping shall comply with
the following:
1) Located in the area with the highest concentration of boiler water
impurities
2) Be extended as far as possible
3) Be perforated with holes not smaller than 10 mm or V-notched
on the top.
7.10 Water Drum Intermittent Blowdown
7.10.1 Intermittent blowdown nozzles shall be located on the lowest point of
water drums. The size shall be based on water quality and operation,
but shall not be less than 1½ inch nor greater than 2 inch NPS.
7.10.2 Separate drain valves shall be provided at the lowest point of water
drums as a means for the draining of boilers.
7.11 Settings and Casings
7.11.1 Drains shall be provided at the low-points of furnaces and bank areas
in order to remove flue gas deposits by water washing.
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7.11.2 Boiler enclosures, including air and gas ducting, shall be weatherproof
and shall be pressure tight without buckling or bowing when subjected
to an internal pressure transient of 1.5 times the furnace operating
pressure.
7.11.3 Bolted access doors shall be provided as required for ready access to
all parts of the equipment for cleaning, inspecting, repairing, and
replacing the tubes and headers. Access to the furnace through burner
openings is not acceptable. Access doors shall be easy to enter from
floor levels or platforms, and shall be clear of all obstructions.
7.12 Structural Steel
7.12.1 The Boiler Supplier shall supply the structural steel necessary to
support the entire operating weight of all parts of a boiler, including
future sootblowers and platforming.
7.12.2 Wind speeds, and seismic forces shall be in accordance with
SAES-A-112.
7.12.3 Boilers shall be designed for wind and earthquake loads in accordance
with ASCE 7.
With reference to ASCE 7, the wind Category Classification to be used
in the calculations of wind loads shall be Category III, and the Seismic
Hazard Exposure Group to be used in calculations of earthquake loads
shall be Group III.
Wind pressures shall be assumed to act on the projected surface area and
shall include due allowances for platforms, ladders, piping, insulation,
and supported equipment.
7.12.4 The design metal temperatures of structures shall be the maximum
calculated metal temperature expected for all operating modes with an
average ambient temperature specified in accordance with SAES-A-112.
7.12.5 Structural steel shall be designed and detailed in accordance with
AISC 325 and AISC 326.
7.12.6 Refractory shall not be used to support structural loads.
7.12.7 Platforms with stairways or ladders shall be in accordance with the
requirements of SAES-B-054, and this specification.
7.12.8 As a minimum platforms with stairways or ladders that are not
accessible from ground level shall be provided for the following:
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1) All stop and non-return valves
2) Superheater, and economizer safety valves
3) Vent, blowdown, drain, and shutoff valves
4) Flue gas draft control and guillotine dampers
5) Access doors, handholes, and manways
6) Burners, sootblowers, and observation ports
7) Fans and fan drivers
8) Instrument and control valves
9) Electrical equipment
10) Stack sampling or monitoring
11) Draft gages
12) Steam Drum instrumentation
7.12.9 Burner platforms shall be provided with at least one stairway and have
access to all other platforms.
7.12.10 Burner platforms shall be arranged to provide easy removal of burner
guns.
7.12.11 Where several levels of burners are installed, each level shall be
provided with a separate platform, with minimum headroom of 2.1 m.
7.13 Materials
7.13.1 All materials shall be in accordance with the ASME SEC II part D and
the selection criteria in this specification for individual components.
7.13.2 Cast iron, or cast steel fittings are not permitted.
7.13.3 When tube support design temperatures exceed 600°C and fuels
contain a vanadium/sodium ratio between 3:1 and 18:1, tube supports
shall be fabricated from high alloy materials: 60% Chromium-40%
Nickel or 50% Chromium-50% Nickel materials. High alloy
components shall not be welded to carbon steel components.
7.14 Valves
Boiler Valves
7.14.1 The selection of gate, globe and check valves shall be in accordance
with the Code.
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Fuel System Valves
7.14.2 All fuel shutoff valves shall be slow-opening, quick-closing, tight shut-
off valves, and shall be certified fire-safe.
7.14.3 Fuel gas and fuel oil shut-off valves shall be either ball or non-
lubricated plug types.
7.14.4 Position indicator handles shall be supplied for all ball and plug type
valves.
8 Sootblowers
8.1 General
8.1.1 When boiler fuels are specified on the data sheet as oil or a
combination of oil and gas, sootblowers shall be provided. When the
fuel is specified as gas only, spaces for the future addition of
sootblowers shall be provided in boiler convection sections.
8.1.2 Rotary sootblowers shall be used in flue gas passes when flue gas
temperature is below 650°C.
8.1.3 Retractable sootblowers shall be used in flue gas passes when flue gas
temperature is above 650°C.
8.1.4 The Boiler Supplier is responsible for providing a complete and
effective sootblowing system designed to remove soot and other
unfused deposits from all convective heat transfer surfaces.
8.1.5 Sootblowers shall be fully automatic with selected sequential control
and manual override capabilities for individual sootblowers.
8.1.6 Each sootblower shall be easily maintainable, with accessible
lubrication fittings at all required lubrication points.
8.1.7 Sootblower entrance ports shall be protected with 3 mm Type 304
stainless steel sleeves.
8.1.8 The sootblower manufacturer's design shall be substantiated by at least
two years of satisfactory experience in comparable service.
8.1.9 A steam flow measuring device as designed by the Design Engineer
shall be installed in sootblower steam supply lines to each boiler.
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8.1.10 Sootblowers shall be provided with connections for water washing of
boilers.
8.2 Piping
8.2.1 The design of sootblower piping shall be arranged so that condensate
buildup drains away from sootblower heads.
8.2.2 Drain valves shall be interlocked with the control valve to ensure that
upstream condensate is drained during warm-up and prior to the
operation of sootblowers.
8.3 Instrumentation and Controls
8.3.1 Each sootblower shall be provided with individual controls to allow the
selection of either manual or automatic operation.
8.3.2 Automatic control shall be obtained via a programmable logic
controller designed and specified by the Design Engineer in
accordance with 34-SAMSS-830.
8.3.3 Initiation of operating modes shall be prevented until steam supply
systems have warmed-up, all condensate has been drained, and steam
pressure has been established upstream of the sootblower control
valves.
8.3.4 The system shall be provided to prevent the start of a sootblower cycle
until any other operating sootblower has completed its cycle.
8.3.5 Automatic mode of operation shall incorporate the following functions:
1) Enable the lockout of any sootblower from normal operating
sequence.
2) Enable the sequence to be "held" at any point in the sequence by
operator intervention, and allow sootblowers to operate in the
manual or local mode during that "hold" period. On re-selection
of the automatic mode, the sootblower sequence shall continue
from where it was interrupted.
3) After two minutes from the initiation of any emergency stop
signal, automatically retracts any operating retractable
sootblower and shuts down the system to a safe condition.
8.3.6 The following are the minimum indications of system status that shall
be provided:
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1) The mode of operation selected
2) When the system is running under automatic sequential control
3) Individual sootblower in operation
4) The direction of travel for individual retractable sootblower
during operation
5) Steam system warm-up period is in progress
6) Steam system warm-up period is completed
7) Any sootblower(s) locked out of the normal operating sequence
8) Open/closed positions of main supply valve
9) Open/closed positions of individual boiler steam supply shutoff
valves
8.3.7 The following are the minimum indications of alarm status:
1) Elapsed time
2) Motor overload
3) Steam pressure
4) Out of sequence
8.3.8 The following shall be provided in control rooms:
1) Alarms and status indications
2) Automatic and manual mode pushbuttons
3) Sootblower selector switches
9 Air Preheaters
9.1 Air preheaters, if cost effective, shall be of the fixed tubesheet recuperative
design.
9.2 Air preheaters shall be shop-prefabricated to minimize field assembly.
9.3 The materials of construction of tubes and tubesheets shall be selected based on
the acid dewpoint corrosion temperature (ADCT) plus 28°C. (The value of the
ADCT shall be calculated on the basis of a 5% conversion of sulfur dioxide to
sulfur trioxide).
9.4 The selection of all other air preheater materials shall be based on flue gas
composition and metal temperatures developed during minimum load operation
at minimum ambient air temperature.
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9.5 All pipe and pipe fittings shall be of steel construction.
10 Economizers
10.1 General
10.1.1 Economizers shall be provided and designed to avoid steaming at all
loads.
10.1.3 Economizers shall be made of Carbon Steel.
10.1.4 Water bypass with double block valves shall be provided for the
economizer to allow emergency operation of the boiler in cases where
the economizer is out of service. Economizer shall be provided with a
block valve and a safety valve.
10.2 Economizer Tubes and Tubesheets
10.2.1 Tubes shall be arranged in either staggered or in-line rows to allow for
higher boiler performance.
10.2.2 Finned tubes, with a maximum of six fins per 25 mm, shall be used.
The fins shall be attached by high-frequency continuous resistance
welding. The fin thickness shall be a minimum of 1.25 mm and the fin
height shall not exceed 25 mm.
10.2.3 Finned tubes with a maximum of 4 fins per 25 mm shall be used when
firing liquid fuels.
10.2.4 Serrated fins shall not be used when firing liquid fuel.
10.2.5 The minimum design metal temperature of tubes and tubesheets shall
be 15°C above the calculated ADCT.
10.3 Enclosures
10.3.1 Where size and shipping facilities permit, economizers and enclosures
shall be prefabricated to allow for field installation with minimum
assembly and welding.
10.3.2 Coil supports may be manufactured from carbon steel when the design
metal temperature is less than 425°C and flue gas is sulfur-free.
11 Firing System Equipment
11.1 General
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11.1.1 Burners shall be of the forced draft type designed to operate
continuously over the specified turndown range.
11.1.2 Flame profiles of all burners shall be contained within the confines of
the furnace without flame impingement on walls, roof, floor, or exit
screen, and without flame penetration through the exit screen to the
superheater space. Take ABMA's definition and put it instead and we
will add it in the definitions section.
11.1.3 The Boiler Supplier shall provide optical flame scanners to each of the
burner assemblies as detailed by the Design Engineer in accordance
with SAES-J-602 and 34-SAMSS-617.
11.1.4 Burners shall be capable of covering all boiler loads from start up to
100% MCR with stable flame. Turndown shall be achieved
automatically, without changing burner tips or impairing flame
stability.
11.1.5 Burners controls shall be designed to facilitate rapid changeover
between fuel types.
11.1.6 Flue gas shall satisfy emission requirements as specified in the data
sheet at operating conditions between 25% to 100% MCR.
11.1.7 Burner and fuel system design shall permit safe fuel switching during
operation and sudden trip of a burner.
11.1.8 Burners shall be designed to minimize exposure to furnace radiation.
Burner components exposed to furnace radiation shall be fabricated
from heat-resistant alloys.
11.1.9 All burner hardware (including piping, tubing, hoses, valves, and
cocks) shall be of steel construction. Cast iron, copper alloys, and
aluminum alloys, are not permitted.
11.1.10 The proposed burner design shall be compatible with the burner
management system in accordance with this specification.
11.1.11 Burners shall be designed to meet sound level limitations as specified
in this specification.
11.1.12 Connections shall be provided to verify combustion air and fuel
balances between burners.
11.1.13 Burner curves shall be submitted and shall show the fuel consumption
over the burner turndown range against fuel pressure required at the
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burner, and burner draft loss (Register Draft Loss) requirement excess
air vs. load, and pressure vs. load, burner pressure vs. MMbtu's.
11.1.14 The air leakage through a closed air register at the rated load shall be a
maximum of 10%
11.1.15 All safety shutoff and vent valves on burner/pilots shall be as specified
by the Design Engineer in accordance with NFPA 85.
11.2 Oil Burner Assembly
11.2.1 Oil burners shall be the high efficiency, with maximum ratio of steam
to fuel oil flow of 1 to 3, atomizing type, and provide uniform
atomization throughout the burner turndown range with an excess air
not more than 15% at MCR
11.2.2 Burners shall not require more than 1034 kPag (150 psig) oil pressure
at the burner.
11.2.3 If the fuel oils specified on the data sheet will require different burner
tips, the burner design shall be such that the only operator action
required to change a burner tip is the withdrawal of a gun after
isolation of the fuel supply.
11.2.4 Positioning and removal of oil gun assemblies shall prevent flashback
when exchanging burner guns.
11.2.5 Oil gun assemblies shall be provided with flexible stainless steel hoses
for fuel oil and atomizing steam.
11.2.6 Air diffusers (swirler) located at the ends of burner positioning pipes
shall be fabricated from heat-resistant alloy.
11.3 Gas Burner Assembly
11.3.1 Gas burners shall be capable of efficiently burning the specified fuels
within the specified range of heating values throughout the burner
turndown range.
11.3.2 Gas burners shall be the high efficiency throughout the burner
turndown range with an excess air not more than 10% at MCR
11.3.3 Gas burners shall be of the multiport design.
11.4 Air Registers
11.4.1 Air register "open" setting shall provide equal distribution of
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combustion air to each burner to assure optimum flame conditions for
the fuel(s) being fired over the turndown range of the burner.
11.4.2 All parts of air registers shall be shielded from furnace radiation and
protected against conducted heat as covered in NFPA 85.
11.5 Pilots
11.5.1 Class 2 or Class 3 gas igniters, as defined in NFPA 85 shall be
supplied.
11.5.2 Pilots shall be the automatic air and gas type, complete with an electric
spark igniter and designed to utilize combustion air supplied by the
main forced draft fan, as specified in NFPA 85.
11.5.3 Pilots shall be blowout proof and capable of attaining ignition while
maximum combustion air flows through the burner.
11.5.4 Pilots shall be designed to resist furnace radiation with the air registers
closed and main burners in operation without cooling air.
11.6 Burner Windboxes
11.6.1 Burner shall be furnished with windboxes, with bolted access doors,
and acoustic insulation where required.
11.6.2 Windboxes shall be provided to assure equal distribution of
combustion air to air registers for each burner.
11.6.3 Where a windbox supplies combustion air to more than two burners,
the Boiler Supplier shall demonstrate the effectiveness of the air
distribution.
11.6.4 A minimum thickness of 5mm is required for the wind box.
11.6.5 All stiffners to the the wind box shall be continuously welded.
11.7 Burner Piping
11.7.1 Burner piping required for oil, gas, and steam including shut-off valves
shall be supplied by the Boiler Supplier.
11.7.2 Tie-ins shall be from the tops of headers.
11.7.3 Fuel headers shall be supplied with blow-down connections.
11.7.4 All piping and valving shall be located, from a single-point entry, for
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each fuel to the fuel rack.
11.7.5 Fuel oil shut-off valves shall be located as close as possible to headers
with no dead legs.
11.7.6 Unless otherwise specified, a strainer with block and bypass valves
shall be supplied for liquid fuels, located in the supply lines to each
boiler. The size of mesh shall be not larger than half of the smallest
orifice diameter in the burner guns.
11.7.7 Hoses shall only be used for atomizing steam and liquid fuels heavier
than 68° API, (0.709 relative density). The design and materials of
hoses shall be as follows:
1) Three ply construction comprising of the following:
a) An inner hose of close pitch corrugated tubing
b) A middle layer of type 321 stainless steel braid
c) An outer layer of interlocked stainless steel armor
2) Either weld-end or flanged connections
3) Hoses are to be installed such that the hose manufacturer's
minimum bend radius is not exceeded, or any moment is applied
while in service.
11.7.8 Piping shall be arranged to ensure that all manually operated valves are
in easy access. Supervisory manually operated valves for each fuel
shall be the last valve before burners and located so that the valve
operator can view the burner flame through the burner observation
ports while operating the valve as per NFPA 85.
11.8 Burner Testing
For non standard burner design a production model of each burner shall be
tested for capacity, flame profile, stability within the turndown range with a
reference list of users. Witness of the test firing is at the discretion of the Saudi
Aramco Inspector.
12 Forced Draft Fans
12.1 General
12.1.1 Fans shall be, low speed type connected to drivers by flexible
couplings with coupling guards.
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12.1.2 Forced draft fans shall be located at ground level and located to permit
easy access to the interior of fan casings and to allow easy removal of
rotors.
12.2 Fan Design
12.2.1 Fans shall be designed for not less than the following conditions:
1) Air flow rated capacity shall be 105% of air flow required for
maximum continuous rating with 15% excess air for fuel oil and
10% excess air for fuel gas.
2) Maximum ambient design temperature and humidity as per
SAES-A-112.
3) Static head shall be 110% of the head required at MCR with 15%
excess air firing for fuel oil and 10% excess air for fuel gas.
4) Operating horsepower, as determined from items (1), (2), and (3)
corrected for density at the minimum ambient design
temperature.
12.2.2 Fans shall be furnished with inlet guide vanes and with a vane drive
arm for connection to the operating source.
12.2.3 Vanes shall be provided with a mechanical stop to prevent airflow
from falling below 25% MCR.
12.2.4 Fans shall be furnished with a double extended shaft, unless specified
otherwise on the data sheet.
12.2.5 Fan housings shall be a minimum of 5 mm thick. The housing shall be
of all-welded construction and shall be equipped with a cleanout door
and a 2 inch NPS drain. Housings shall be constructed to allow for
rotor removal.
12.2.6 Fans shall be provided with split-sleeve bearings and be self-aligning,
oil lubricated, with independent pedestals and soleplates, or antifriction
bearings may be offered as an alternative.
12.2.7 Air intakes of fans located outdoors shall be provided with bird screens
and with means to avoid pickup of rain and wind-driven sand. The
inlet shall also be designed to avoid wind effects on combustion
airflow measuring devices.
12.2.8 If required, air intake and discharge ducts shall be provided with
silencers in order to meet the noise level limitations specified.
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12.3 Fan Drivers
12.3.1 Drivers shall be as specified on the data sheet and shall be in
accordance with the specified electric power supply and steam
conditions.
12.3.2 Turbine drivers shall conform with the requirements of 32-SAMSS-009.
12.3.3 Motor drivers shall conform with the requirements of 17-SAMSS-503.
12.3.4 Geared drives shall be separately coupled units with a minimum
service factor of 1.5. Gear shafts shall be equipped with split-sleeve
bearings. A torsional analysis shall be prepared for geared units.
13 Ductwork
13.1 General
13.1.1 The Boiler supplier shall furnish a complete ductwork system for
combustion air travel from air intake fans to burner windboxes.
13.1.2 The system shall include supports, expansion joints, hangers, access
doors, dampers, isolation plates, and connections for the measurement
of airflow, temperature, and pressure.
13.1.3 Flue gas ducting from the outlet to the stack, with all the necessary
appurtenances, shall be furnished by the Boiler supplier when specified
on the data sheet.
13.2 Design
13.2.1 Ducts for air and flue gas shall be designed, arranged, and installed in a
manner to prevent vibration, distortion, and undue noise.
13.2.2 Ducts shall be airtight and gastight. The maximum velocity of air and
flue gas shall not exceed 20.0 m/s.
13.2.3 Ducts shall be capable of withstanding an internal transient pressure of
14 kPa (2 psi).
13.2.4 The minimum thickness of flue gas ducts shall be 5 mm and air ducts
shall be 5 mm minimum thickness.
13.2.5 Where more than one boiler exhausts to a common stack, an isolating
plate, complete with davits, and flange spreaders, shall be provided in
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the discharge ducting of each boiler. Isolation plates shall be designed
for tight shut-off and maximum fan discharge pressure.
13.2.6 Flanged connections shall be complete with flanges, erection bolts, and
nuts. Flanges shall be sealwelded in the field.
13.2.7 Ductwork shall be shop-fabricated for field assembly, including the
installation of supports required for external insulation or internal
refractory lining.
13.2.8 An expansion joint shall be provided between force draft fans and the
discharge ducting to boiler.
13.2.9 Internal lining shall be provided where the metal temperature is less
than the calculated value for ADCT. Alternately, external insulation
shall be used where applicable.
14 Stacks
14.1 Stacks shall be furnished by the Boiler Supplier.
14.2 Boilers shall be provided with a common self-supported stack. Unless otherwise
specified on the data sheet, the minimum stack height above grade shall be 45 m.
14.3 The Boiler Supplier shall calculate and guarantee emission rates of nitrogen
oxides and sulfur oxides. The emission rates shall be expressed in Lb/MM
BTU's when the boiler is operated at its design rate firing the fuels specified.
Flue gas emissions (NOx, CO, particulates, hydrocarbons, etc.) shall not exceed
the specified levels as per SAES-A-102.
14.4 Where the stack metal temperature at any operating load can be less than the
calculated value for ADCT a 50 mm castable refractory lining shall be provided.
14.5 All external attachments to the shell shall be continuously welded.
14.6 The design of refractory systems shall be in accordance with SAES-N-100.
15 Insulation and Refractories
15.1 General
15.1.1 Headers, drums, air heaters, economizer casings, windboxes, external
superheater headers, exposed tubes, hot gas ducts, hot air ducts, steam
turbines, and other heated and exposed surfaces shall be insulated in
accordance with SAES-N-001.
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15.1.2 The design of refractory systems shall be in accordance with
SAES-N-100.
15.1.3 Refractory shall be installed in accordance with SAES-N-110,
SAES-N-130, and SAES-N-140.
15.2 Ductwork
15.2.1 Corners of insulation on ductwork shall be protected with metal corner
beading. Insulation on ducts shall be properly supported and securely
fastened.
15.2.2 Clips or welding studs for holding wires and bands shall be spaced a
maximum of 450 mm on center. Exposed supports, duct doors, and
other parts that project through the insulated surfaces shall be insulated
for protection of personnel.
15.2.3 Where the metal temperature of flue gas duct, at any operating load, is
less than the calculated value of the ADCT, a 50 mm castable
refractory lining shall be provided. Alternately, external insulation
shall be used where applicable.
16 Noise Attenuation
16.1 The Engineering company shall specify limits for the sound pressure levels
(SPL) and sound power levels (PWL) at the designated locations, on Form
7305-ENG.
16.2 The boiler supplier shall ensure that the required limits as specified for SPL and
PWL can be achieved by supplying test results of a representative boiler.
16.3 Boilers shall be designed and provided with the acoustical treatment necessary
to meet the specified noise levels. This shall include burner mufflers and
acoustical lining for plenums, ducts, and stacks, vent silencer as required.
17 Connections, Boiler Trim and Instruments
17.1 General
17.1.1 The Boiler supplier shall supply all connections and equipment in
accordance with this specification.
17.1.2 All instrument connections, except thermowells, shall be provided with
separate block valves to permit removal of devices without affecting
other active devices.
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17.1.3 Steam drum connections shall be provided for level instrumentation in
accordance with SAES-J-602.
17.1.4 Connections shall be provided for the chemical cleaning of boilers,
superheaters, and economizers.
17.1.5 Drain connections shall be provided for draining all water after
shutdown or boilout. Valves shall be 2 inch NPS minimum and located
at the lowest point on the water drum to allow complete drainage of
boilers in one hour or less at a pressure of 35 kPa g (5 psig).
17.1.6 Connections shall be provided for the quick draining of all
accumulated water in areas of furnaces, superheaters, boiler banks, and
economizers following water washing of external tube surfaces.
17.1.7 A sealing air system shall be provided from forced draft fan discharge
ducts for all burner removal openings, sootblower wall boxes, and
observation ports. Flexible connections between the sealing system
and air supply lines may be used to compensate for differential
expansion.
17.2 Boiler Trim
The minimum boiler trim requirements to be provided by the Boiler supplier,
shall be as follows:
1) Safety valves for drums, superheater outlets, and economizers in
accordance with the requirements of the Code and 34-SAMSS-611.
Valves shall be complete with discharge piping to a point 3 m above the
nearest platform. Safety valves shall be equipped with lifting levers.
2) A steam outlet stop valve and a screw-down non-return valve, each with a
pressure-sealed bonnet and of approved boiler quality. A pressure-
equalizing warm-up line of not less than 2 inch NPS shall be provided
around stop valve.
3) Intermittent blowdown valves, using two valves in series at each
blowdown nozzle. The outside valve shall be quick-opening, except at
water wall headers.
4) Boiler feedwater shutoff and check valves.
5) Boiler vent valves, using two valves in series at each location.
6) Valves for obtaining representative saturated steam samples, using two
valves in series (double block) at least one down stream of SD and one
superheated steam sample downstream of the SH. If the boiler design
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includes a series of small-diameter tubes between the steam drum and
superheater header, the sample points shall be spaced no more than 1.5 m
apart. Sample connections shall be in accordance with ASTM D1066.
7) Continuous blowdown valves, using two valves in series. The downstream
control valve shall be a hand-operated, V-port valve with a micrometer
indicator or a V-port valve with TDS/conductivity control.
8) Chemical feed valves, using two block valves in series and a check valve.
9) Superheater drain and vent valves, using two valves in series at each
location.
10) Lower header drain valves, using two valves in series for each connection.
11) A sample connection with two valves in series for obtaining representative
water samples. The sample connection shall be located upstream of the
continuous blowdown control valve.
12) Lower drum drain valves, using two valves in series at each location.
13) Three sample coolers (in accordance with ASTM D1066), valving and
drainage trough. The sample piping and valving shall be arranged such
that boiler water, saturated steam, and final steam each have a dedicated
cooler.
14) Desuperheater water shutoff and check valves.
15) Sootblower steam valves, using two valves in series at each location.
16) Economizer outlet stop valve and screwdown non-return valve, where a
water bypass is included.
17) Economizer safety valve (in accordance with the Code) if a bypass is
included.
17.3 Pipework
The minimum piping to be supplied by the Boiler supplier shall be as follows:
1) Steam piping from the superheater outlet header to the main stop valve
2) Interconnecting steam piping between superheater stages and the
desuperheater
3) Saturated steam piping from the steam drum to the superheater inlet header
4) Interconnecting piping from the economizer to the steam drum
5) Boiler feedwater piping from the check valve to the economizer inlet header
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6) Complete piping for the sealing air system, from the FD fan to all users
7) Complete piping for the air system from a single point supply connection
to all users
8) All drain piping from the source to 1 m above grade
17.4 Instrumentation and Safety Relief
17.4.1 The minimum instrument requirements shall be in accordance with the
Code and the following:
1) A combination airflow metering element shall be provided in the
forced draft fan inlet or discharge duct. The flowmeter element
shall be located upstream of any air-heater and be either a
multipoint thermal mass flowmeter or a different head venturi or
airfoil section.
Differential head elements shall be capable of generating a
differential head pressure up to 250 mm water gage at maximum
flow.
2) Sample connections for oxygen and combustible analyzers at the
furnace exit, boiler, economizer, and air preheater outlets.
3) Connections for flame monitoring and scanning.
4) Connections for the measurement of opacity, particulate matter,
sulfur dioxide, nitrogen oxides, oxygen, and carbon monoxide
5) Connections for draft gages at fan inlet and discharge, air outlet
of the air preheater, windbox, furnace, boiler outlet, economizer
outlet, flue gas outlet of the air preheater, and stack entry.
6) Thermocouple wells for measuring the steam temperature after
each stage of superheaters, including the steam temperature
before and after the desuperheater. Thermowells shall also be
provided for measuring the temperature of the feedwater out of
the economizer.
7) Thermocouple wells for measuring flue gas temperatures leaving
the furnace, air preheater, boiler, and economizer thermowells for
measuring air temperatures before and after the air preheater and
in the windbox, with provision for purging. The thermocouple
hot junction shall be located to measure the average flue gas
temperature, and shall be shielded to minimize the cooling effects
of the surrounding surfaces.
Document Responsibility: Heat Transfer Equipment 32-SAMSS-021
Issue Date: 18 January 2010
Next Planned Update: 18 January 2015 Manufacture of Industrial Boilers
Page 34 of 34
17.4.2 All instrumentation shall be in accordance with the Code, NFPA 85,
and SAES-J-602.
17.4.3 Safety relief devices shall be designed in accordance with the Code.
18 Burner Management Systems
18.1 Unless otherwise specified in the purchase order, boiler supplier shall supply a
burner management system in accordance with NFPA 85, SAES-J-602 and
34-SAMSS-619.
18.2 All nozzles, instrument connections, and thermowells for the burner
management system shall be supplied by the Boiler Supplier.
19 Painting
19.1 All exposed surfaces shall be prepared and painted in accordance with
SAES-H-001, SAES-H-100, and SAES-H-101.
19.2 Gasket contact surfaces shall not be painted.
20 Fabrication
20.1 Forming and Assembly
20.1.1 The layout of shell plates, heads, and head plates shall be made in such
a manner that manways, nozzles and their reinforcement are not
located within any weld seams. Manways, nozzles and their
reinforcement shall not be located within 20 mm of any weld seam.
20.1.2 All nozzles and manways shall be ground flush to the inside curvature
of the drums and headers, and inside diameters shall be radiused
smooth.
20.1.3 Where a split-reinforcing pad is required, the weld joining the pad
sections shall be oriented with the circumferential direction of the
shell. Tapped tell-tale holes ¼ inch NPT shall be provided as follows:
1) One hole in all single piece reinforcing pads.
2) Where a pad is split, each segment shall have at least one tapped
hole.
20.1.4 All internal and external nonpressure-welded attachments shall be fully
seal welded and shall have their radiused corners.
Document Responsibility: Heat Transfer Equipment 32-SAMSS-021
Issue Date: 18 January 2010
Next Planned Update: 18 January 2015 Manufacture of Industrial Boilers
Page 35 of 35
20.2 Welding
All welding shall be in accordance with the requirements of ASME SEC I.
21 Nondestructive Testing
21.1 General
21.1.1 All Nondestructive Testing (NDT) shall be performed in accordance
with the Boiler supplier written procedure prepared in accordance with
ASME SEC V with the scope of NDT and acceptance/rejection criteria
as defined by the Code and this specification.
21.1.2 All NDT on boiler drums which are to be postweld heat-treated shall
be made after postweld heat treatment.
21.1.3 All pressure and nonpressure welds shall be visually inspected.
21.2 Radiographic Testing
21.2.1 Radiographic testing of tube support castings shall be conducted on
any cracks or other indications exposed by liquid penetrant inspection
that exceeds the quality requirements of ASME SEC I, PG-25.
21.2.2 Areas of stress concentration in corners of castings, especially at
support lugs, shall be radiographically inspected. At least two spot
radiographs shall be taken of the lower flanges of each cast tube
support section.
21.2.3 One random spot radiograph shall be made for circumferential weld
and one random radiograph for longitudinal welds of each stack shell
section. In addition, each longitudinal and circumferential welds
intersection shall be radiographed in the circumferential direction.
21.2.4 All personnel performing field radiography at Saudi Aramco facilities,
sites, and concessionary areas shall be in possession of valid permit to
handle and use radioactive ionization materials and equipment.
21.3 Ultrasonic Testing
21.3.1 All butt-welds on boiler piping, 32 mm wall thickness and thicker shall
be ultrasonically tested. Ultrasonic examination and interpretation
shall be in accordance with ASME SEC VIII.
21.3.2 Tubesheets and forgings 50 mm and thicker shall be ultrasonically
tested in accordance with ASTM A435.
Document Responsibility: Heat Transfer Equipment 32-SAMSS-021
Issue Date: 18 January 2010
Next Planned Update: 18 January 2015 Manufacture of Industrial Boilers
Page 36 of 36
21.4 Magnetic Particle Testing
21.4.1 Beveled edges of carbon steel plates with thicknesses 25 mm and thicker
and all ferrous alloy plates shall be magnetic particle examined for linear
discontinuities. Defects shall not exceed limits as per ASTM A20.
21.4.2 All internal and external welds for all services made using the SMAW
welding process when the nominal thickness of pressured components
is 25 mm and thicker shall be magnetic particle tested.
21.5 Hardness Testing
Weld hardness testing shall be in accordance with the requirements of
ASME SEC I.
22 Postweld Heat Treatment
22.1 Code exemptions for postweld heat treatment of ferritic materials based on the
use of austenitic or nickel-based electrodes are not permitted.
22.2 The maximum postweld heat treating soaking temperature for carbon steel and
C-½ Mo materials shall not exceed the temperature at which the test pieces were
heat treated, as shown on the Mill Test Certificates or 650°C for carbon steel
and 690°C for C-½ Mo.
22.3 The maximum postweld heat treating soaking temperature for low-chrome alloy
steels shall not exceed the tempering temperature at which test pieces and
components were heat treated as shown on Mill Test Certificates, but shall be
not less than 700°C.
22.4 Postweld heat treatment shall follow all welding and repairs but shall be
performed prior to any hydrotest or other load test.
22.5 Postweld heat treating shall be in accordance with the requirements of
ASME SEC I and ASME SEC IX.
23 Inspection and Equipment Testing
23.1 Inspection
23.1.1 All materials and fabrication shall be subject to inspection by the Saudi
Aramco Inspector in accordance with Saudi Aramco Inspection
Requirements Form 175-321300.
23.1.2 Written reports and evaluations of all inspections performed by the
Boiler Supplier shall be made and submitted to the Saudi Aramco
Document Responsibility: Heat Transfer Equipment 32-SAMSS-021
Issue Date: 18 January 2010
Next Planned Update: 18 January 2015 Manufacture of Industrial Boilers
Page 37 of 37
Inspector, at a frequency to be determined by the Saudi Aramco
Inspector.
23.1.3 Written reports and evaluations of all inspections performed by the
Boiler Supplier shall be made and submitted to the Saudi Aramco
Inspector, at a frequency to be determined by the Saudi Aramco
Inspector.
23.1.4 Prior to final inspection and pressure testing, the inside and outside of
boilers shall be thoroughly cleaned of all slag, scale, dirt, grit, weld
spatter, paint, oil, etc.
23.1.5 The Saudi Aramco Inspector shall have free access to the work at all
times.
23.1.6 Refractory linings and materials shall be inspected in accordance with
SAES-N-110, SAES-N-130, and SAES-N-140.
23.2 FD Fan Testing
Fans shall be tested by the Boiler Supplier in accordance with AMCA 210 and
the following:
1) No load, full speed run test
2) One Aerodynamic performance test per FD fan type.
23.3 Boiler Performance Testing
23.3.1 A performance test, shall demonstrate complete and smokeless
combustion without flame impingement on the furnace heating surface
or flame penetration through the furnace exit screen, at all loads within
the turndown range, and with any fuel or combination of fuels
available at the time of the test on each boiler.
23.3.2 Boiler efficiency shall be based on the higher heating value of the fuel,
and the tests shall be made in accordance with ASME PTC 4,
Performance Test Code (Abbreviated Method). If the results of a
performance test do not conform in with the guaranteed values, the
Boiler Supplier shall immediately correct deficiencies.
23.3.3 Unless otherwise specified, the acceptance test shall be performed by
the Boiler Supplier representative after commissioning.
23.3.4 In addition to the Code, the following represent the minimum shop
leak tests:
Document Responsibility: Heat Transfer Equipment 32-SAMSS-021
Issue Date: 18 January 2010
Next Planned Update: 18 January 2015 Manufacture of Industrial Boilers
Page 38 of 38
Hydrostatic test of all pre-assembled pressure-containing sections, in
accordance with the Code and SAES-A-004.
23.3.5 In addition to the Code, the following represent the minimum field leak
tests:
A hydrostatic test of all pressure parts in accordance with the Code,
prior to installation of the casing.
23.3.6 Field pressure testing shall be in accordance with the Code.
23.3.7 After inspection and testing, boilers shall be completely drained of all
liquids.
24 Nameplates and Stampings
24.1 Boilers shall be Code stamped.
24.2 Nameplates and nameplate mounting bracket shall be located such that they will
not be covered by insulation and is easily readable from grade or a platform.
25 Preparation for Shipment
25.1 General
25.1.1 The Boiler Supplier is responsible for preparing materials for shipment
and assuring their arrival on-site in good condition.
25.1.2 All components shall be packed, securely anchored and satisfactorily
protected for their respective shipment methods.
25.1.3 One complete set of installation, operating, and maintenance
instructions necessary for installation shall be packaged and shipped
with the equipment.
25.1.4 Bracing, supports, and rigging connections shall be provided to prevent
damage during shipment, lifting and unloading.
25.1.5 All instruments and valves, including auxiliary systems, shall be
securely mounted, supported, and/or boxed to avoid damage during
shipment.
25.1.6 All exposed finished and machined surfaces, including bolts, shall be
coated with a rust-inhibiting compound.
Document Responsibility: Heat Transfer Equipment 32-SAMSS-021
Issue Date: 18 January 2010
Next Planned Update: 18 January 2015 Manufacture of Industrial Boilers
Page 39 of 39
25.1.7 Bearings and seal assemblies shall be fully protected against the entry
of moisture and dirt.
25.1.8 Flanged connections and all other machined surfaces shall be protected
by a coating, which is easily removed in the field. Flanges shall be
fitted with a steel or wood cover, 3 mm thick and neoprene gaskets.
25.1.9 Covers shall be securely attached by a minimum of four bolts equally
spaced. For ocean shipment, flanged connections shall also be covered
with heavy duty plastic bags securely taped to the nozzles.
25.1.10 Markings shall be done with water soluble materials that contain no
harmful substances that would attack or harmfully affect coils at both
ambient and operating temperature.
25.1.11 Marking materials shall be free of lead, sulfur, zinc, cadmium,
mercury, chlorine, or any other halogens.
25.1.12 Threaded connections, shall be protected with threaded plugs.
25.2 Internal Protection
25.2.1 The internals of drums and headers shall be protected from corrosion
by use of a nontoxic vapor phase corrosion inhibitor applied at a rate of
1 kg/m³. Desiccants may only be used with approval of the Saudi
Aramco Engineer.
25.2.2 Drums and headers must be sealed vapor tight using metallic covers,
for inhibitors to be effective.
25.2.3 Alternatively, nitrogen blanketing, temporary coatings or a vapor proof
bag with moisture control may be used.
25.3 External Protection
The protection of external surfaces shall be obtained by using one of the
following:
1) A hard temporary preservative which can be removed at site prior to
surface preparation and application of the Saudi Aramco coating and
painting system.
2) Prepare the surface and apply the complete (primer and final coatings)
Saudi Aramco surface preparation, and coating and painting system in the
shop.
Document Responsibility: Heat Transfer Equipment 32-SAMSS-021
Issue Date: 18 January 2010
Next Planned Update: 18 January 2015 Manufacture of Industrial Boilers
Page 40 of 40
26 Drawings, Calculations and Data
26.1 The Boiler Supplier shall prepare and submit for approval and review the
preliminary and certified drawings and data detailed on Form NMR-7913.
26.2 Drawings and calculations which are approved by the Design Engineer shall not
relieve the Boiler Supplier of responsibilities to comply with the Code, and this
specification.
26.3 The Engineering Company is responsible for the completion of the Safety
Instruction Sheet Saudi Aramco Form 9570-ENG in accordance with
SAES-A-005 and the data on the Boiler Supplier drawings.
27 Life Cycle Cost Evaluation
Unless otherwise approved by the Coordinator, Mechanical Engineering Division,
Consulting Services Department, Quotations for boilers shall be evaluated on the basis
of Life Cycle Cost (LCC) as explained in SAEP-341. This cost is composed of the
initial purchase cost of the Boilers(s) plus the present worth of the fuel consumption
over an assumed operating period of 15 years. The Life Cycle Cost of the Boiler(s)
shall be determined using the following Life Cycle Cost spreadsheets:
LCC-024, Single Fuel Boilers
LCC-024A, Dual Fuel Boilers
The efficiency of the boiler at 100% of the design heat releases shall be guaranteed. If
the actual efficiency during performance tests is found to be less than the guaranteed
efficiency. If not corrected, then the cost of the boiler(s) shall be reduced by an amount
equal to the difference in fuel consumption (MMBTU/hr) for not meeting the
guaranteed efficiency, multiplied by the Evaluation Factor $-hr/MMBTU as given in the
Provided Life Cycle Cost spreadsheets included with boiler data sheet. The maximum
reduction shall not exceed 15% of the initial cost of the boiler(s).
Mathematically:
Single Fuel:
Efficiency Penalty = [actual efficiency - (guaranteed efficiency-0.01)] * L * EF
Commentary Note:
Efficiency values are in decimal representation. 0.01 in the equation is a 1% test tolerance allowed.
EF = PV * EC * AH
Document Responsibility: Heat Transfer Equipment 32-SAMSS-021
Issue Date: 18 January 2010
Next Planned Update: 18 January 2015 Manufacture of Industrial Boilers
Page 41 of 41
Dual Fuel:
Efficiency Penalty = Sum of Efficiency Penalty of all fuels
For each type of fuel the evaluation factor is defined by
EF = PV * EC * T
Where;
L = Boiler Load (Duty) @ normal condition (MMBTU/hr) will be show
on the data sheet.
EF = Evaluation Factor ($-hr/MMBTU) will be shown on the data sheet
that goes with the quotation request
EC = Energy cost in $/MMBTU for each fuel
AH = Annual operating hours
= OF * 8760
OF = Operating Factor, equal 1
PV = Present value factor = 5.85 based on 15% discount rate expressed as a
decimal number and operating period of 15 years.
T = Operating time for each fuel type, in hours
Revision Summary
18 January 2010 Major revision.
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