1、See ALERT85NFPABoiler andCombustion SystemsHazards Code2015ISBN: 978-145591038-0 (Print) ISBN: 978-145591084-7 (PDF)IMPORTANT NOTICES AND DISCLAIMERS CONCERNING NFPASTANDARDS NOTICE AND DISCLAIMER OF LIABILITY CONCERNING THE USE OF NFPA STANDARDSNFPAcodes, standards, recommended practices, and guide
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11、ERNING NFPASTANDARDS Copyright 2014 National Fire Protection Association. All Rights Reserved.NFPA85Boiler and Combustion Systems Hazards Code2015 EditionThis edition of NFPA 85, Boiler and Combustion Systems Hazards Code, was prepared by the Tech-nical Committees on Fluidized Bed Boilers, Fundament
12、als of Combustion Systems Hazards, HeatRecovery Steam Generators, Multiple Burner Boilers, Pulverized Fuel Systems, Single BurnerBoilers, and Stoker Operations and released by the Correlating Committee on Boiler CombustionSystem Hazards. It was issued by the Standards Council on November 11, 2014, w
13、ith an effectivedate of December 1, 2014, and supersedes all previous editions.ATentative Interim Amendment (TIA) to 8.9.2 was issued on November 11, 2014. Errata to6.4.2.1.6 and A.6.4.2.1.6 were issued on July 13, 2016. For further information on tentativeinterim amendments, see Section 5 of the Re
14、gulations Governing the Development of NFPAStandards, available at: http:/www.nfpa.org/regsThis edition of NFPA 85 was approved as an American National Standard on December 1,2014.Origin and Development of NFPA 85NFPA 85 has a long history of documents that were combined to form the present-dayNFPA
15、85. (See Annex M, which is a flowchart depicting the complex development ofNFPA 85.) The first of these documents, in 1924, was NBFU 60, “Regulations of the NationalBoard of Fire Underwriters for the Installation of Pulverized Fuel Systems as Recommendedby the National Fire Protection Association,”
16、which changed from an NBFU/NFPA documentto an NFPA code in 1946.The 2001 edition of NFPA 85 was a compilation of the following six standards:NFPA 8501, Standard for Single Burner Boiler OperationNFPA 8502, Standard for the Prevention of Furnace Explosions/Implosions in Multiple Burner BoilersNFPA 85
17、03, Standard for Pulverized Fuel SystemsNFPA 8504, Standard on Atmospheric Fluidized-Bed Boiler OperationNFPA 8505, Standard for Stoker OperationNFPA 8506, Standard on Heat Recovery Steam Generator SystemsIn the 2001 edition, significant new material was added for multiple burner boilers, includ-ing
18、 requirements for reburn systems. For heat recovery steam generators, the minimumpurge flow requirements prior to starting the combustion turbine were reduced.The 2004 edition was reorganized to provide administrative requirements in Chapters 1, 2,and 3 and common requirements in Chapter 4, Fundamen
19、tals of Boiler Combustion Systems.Subsequent chapters covered the specific requirements for each of the boiler and combus-tion systems covered by the document. The 2004 edition also provided new requirements thataddressed selective catalytic reduction (SCR) systems for multiple burner boilers.In the
20、 2007 edition, Annex M was added to assist users to better understand the complexdevelopment of what is now known as NFPA 85. Chapter 4 in the 2007 edition also includednew requirements for flue gas path auxiliary systems and flame proving, along with support-ing annex material.The 2007 edition reco
21、gnized the use of valve proving systems for single burner boilers inChapter 5. Furnace structural design requirements for multiple burner boilers were added toChapter 6 and account for the impact of booster fans. Implosion protection was clarified asnot being required on units that have no fan in th
22、e flue gas stream downstream of the boiler.In conjunction with those changes, a definition of booster fan was added to Chapter 3. Newrequirements for flue gas path auxiliary systems were added to Chapters 6 and 7 for multipleburner boilers and fluidized-bed boilers, respectively. New requirements we
23、re added forlance and burner safety shutoff valves on fluidized-bed boilers.851NFPA and National Fire Protection Association are registered trademarks of the National Fire Protection Association, Quincy, Massachusetts 02169.The scope of Chapter 8 was expanded in the 2007 edition from heat recovery s
24、team generators to include othercombustion turbine exhaust systems that present similar fire and explosion hazards, including those with no heatrecovery. The definition of combustion turbine exhaust systems was added to Chapter 3, and other changes were madethroughout the code as required for consis
25、tency. Additional combustion turbine interlocks were added to ensure fuelgas in-leakage does not occur during the combustion turbine purge and that excessive fuel is not introduced duringcombustion turbine light-off.The 2011 edition incorporated a renumbering and reorganization of Chapter 4 to make
26、it easier to use and cite. Inaddition, Chapter 4 expanded requirements and annex guidance for burner management systems to describe thetypes of signals and transmitters used to initiate safety alarms and interlocks and how those signals should be moni-tored for reliability. Chapter 4 was updated wit
27、h modified requirements for continuous trend display for single burnerboilers to require only those parameters critical to operation.A definition of combustion turbine purge credit was added to Chapter 3, and requirements for the credit to Chapter 8,in the 2011 edition. The combustion turbine purge
28、credit enables designers and operators to establish and maintain a“purged” condition for HRSGs for an extended period of time between restarts.Guidance was also added to Annex A of the 2011 edition regarding flue gas analyzers in Chapters 5, 6, and 7concerning the potential for certain types to prov
29、ide a source of ignition during startup. In Chapter 6, which addressesmultiple burner boilers, the “all fan trip” purge requirements were revised for clarity and to improve the safety of thatprocedure.The 2015 edition incorporates new requirements in Chapter 4 for safely purging fuel gas piping syst
30、ems, both intoand out of service. The coverage in NFPA 85 begins at the newly defined equipment isolation valve. All gas- and liquidfuelfired boilers are required to be installed with an identifiable equipment isolation valve that demarcates equip-ment within the scope of NFPA 85 from piping and equ
31、ipment within the scope of other codes and standards, such asNFPA 54, National Fuel Gas Code, or ASME B31.1, PowerPiping. The new purge requirements contain provisions address-ing piping and equipment, both upstream and downstream of the equipment isolation valve.Several provisions have been relocat
32、ed from Chapter 6, Multiple Burner Boilers, to Chapter 4, General Require-ments, so that they apply to all equipment under the scope of NFPA 85, including conducting a process hazard analysisfor unattended operation, restrictions on removing interlocks from service during startup or operation, and p
33、revent-ing the flow of flue gases from a common stack into an idle boiler or HRSG. A provision has been added to Chapter 5to exempt some single burner boilers from the process hazard analysis.The 2015 edition recognizes the use of safety-rated programmable logic controllers for use with single burne
34、rboilers where they are certified as at least SIL 3 capable according to IEC 61508, Functional Safety of Electrical/ElectronicProgrammable Electronic Safety-Related Systems.Chapter 9, Pulverized Fuel Systems, has been completely rewritten in the 2015 edition to separate requirements fordirect-fired
35、and indirect-fired systems to assist users in identifying and applying requirements for specific equipment.The requirements for indirect-fired systems have been greatly expanded and clarified so that the chapter is easier toapply to the unique hazards related to those types of systems. In addition,
36、the “strength of equipment” requirementshave been modified to recognize that the 344 kPa (50 psi) pressure threshold is really a maximum allowable workingpressure (MAWP) and that this MAWP is associated with pulverized fuel having Pmaxof 10 bar-g (145 psig) or less, asidentified in NFPA 69, Standard
37、 on Explosion Prevention Systems. Chapter 9 has been updated to reflect the new terminol-ogy and methodology.Finally, the annex material has been reorganized in the 2015 edition so that all supplemental information onstokers is contained in a single annex (Annex F) and all supplemental information o
38、n fluidized-bed boilers also iscontained in a single annex (Annex D).852 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE2015 EditionCorrelating Committee on Boiler Combustion System HazardsMichael C. Polagye, ChairFM Global, MA IBarry J. Basile, Babcock Power, Inc., MA MFred P. Buckingham, MPR Associates
39、, Inc., TX SEDavid Paul Cannon, Hurst Technologies, TX SEKevin Colloton, Rockwell Automation, WI MDavid S. Eason, Detroit Edison Company, MI UJoseph E. Fehr, Sega, Inc., KS SERonald J. Fleming, ABB Incorporated, OH MGordon G. Gaetke, The Dow Chemical Company,TX UDavid W. King, American Electric Powe
40、r Corporation,OH UMasaaki Kinoshita, Mitsubishi Heavy Industries Ltd.,Japan MGail J. Lance, Babcock cansimultaneously also be pulverizer air and/or transport air.3.3.2.7 PulverizerAir. Air or inert gas that is introduced intothe pulverizer to dry the fuel, aid in pulverization and classifi-cation, a
41、nd convey the pulverized fuel from the pulverizer.3.3.2.8 Seal Air. Air or inert gas supplied to any device atsufficient pressure for the specific purpose of minimizingcontamination.3.3.2.9 Secondary Air. Air for combustion supplied to theburners or fuel bed in addition to the primary air.3.3.2.9.1
42、Secondary Air (in a Bubbling Fluidized Bed). Thatportion of the air introduced through the air distributor.3.3.2.9.2 Secondary Air (in a Circulating Fluidized Bed). Thatportion of the air entering the combustor at levels abovethe air distributor.3.3.2.9.3 Secondary Air (in a Single or Multiple Burne
43、r Boiler).That portion of the air entering through the air registers.3.3.2.10 Tempering Air. Cool air added to the hot primaryair or gas to modify its temperature.3.3.2.11 Transport Air. Air or inert gas that is used to con-vey pulverized fuel.3.3.2.11.1 TransportAir(inaFluidizedBed). The air used t
44、oconvey or inject solid fuel or sorbent or to recycle material.3.3.2.12 UndergrateAir. Combustion air introduced belowthe grate.8513DEFINITIONS2015 Edition3.3.3 Air Change. A quantity of air, provided through a fuelburner, equal to the volume of furnace and boiler gas passes.3.3.4 AirRegister A set
45、of dampers for a burner, or air supplysystem to a particular burner, used to distribute the combus-tion air admitted to the combustion chamber. Frequently con-trols the direction and velocity of the airstream for efficientmixing with the incoming fuel.3.3.5 Air-Rich. Indicating a ratio of air to fue
46、l supplied to acombustion chamber that provides more than the minimumexcess air needed for optimum combustion of the fuel.3.3.6 Alarm. An audible or visible signal indicating an off-standard or abnormal condition.3.3.7 Alteration. A change or modification that results in adeviation from the original
47、 design specifications or criteria.3.3.8 Annunciator. A device indicating an off-standard or ab-normal condition by both visual and audible signals.3.3.9 Atmospheric Fluidized Bed Combustion. A fuel-firingtechnique using a fluidized bed operating at near-atmosphericpressure on the fire side.3.3.10 A
48、tomizer. The device in a burner that breaks downliquid fuel into a finely divided state.3.3.10.1 Mechanical Atomizer. The device in a burner thatbreaks down liquid fuel into a finely divided state withoutusing an atomizing medium.3.3.11 Atomizing Medium. A supplementary fluid, such assteam or air, t
49、hat assists in breaking down liquid fuel into afinely divided state.3.3.12 Augmented Air Firing. Supplementary firing with theaddition of air at the duct burners to support and stabilizecombustion or to reduce emissions.3.3.13* Autoignition Temperature (AIT). The minimum tem-perature required to initiate or cause self-sustained combus-tion of a solid, liquid, or gas independently of the heating orheated element.3.3.14 Bed Compartments. Segments of a fluidized bed,which might be individually controlled with respect to com-bustion airflow and fuel feed.3.3.15
