First Correlating Revision No. 1-NFPA 85-2013 [ Section No ... · 3.3.52.1 Booster Fan. A devicefan used to assist in the supply of air to, or the removal of flue gas products

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First Correlating Revision No. 1-NFPA 85-2013 [ Section No. 3.3.52.1 ]

3.3.52.1 Booster Fan.

A device fan used to assist in the supply of air to, or the removal of flue gas productsfrom, the combustion chamber or to supplement draft capability to achieve required flowthrough the combustion air or flue gas flow path.

Submitter Information Verification

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Submittal Date: Wed Jun 26 09:11:49 EDT 2013

Committee Statement

CommitteeStatement:

The word "device" is changed to "fan" in all subdefinitions to provide consistency interminology and restricts the definition to fans and not other devices that could causeair or flue gas flow.




3.3.52.3 Forced Draft (FD) Fan.

A device fan used to pressurize and supply ambient air to the combustion chamber tosupport combustion. In a fluidized bed boiler, FD fans generally include both primary airand secondary air fans.




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Committee Statement

CommitteeStatement:

The word "device" is changed to "fan" in all subdefinitions to provide consistency interminology and restricts the definition to fans and not other devices that could causeair or flue gas flow.




3.3.52.4 Induced Draft (ID) Fan.

A device fan downstream of the combustion process used to remove the products ofcombustion from the boiler, or HRSG by introducing a negative pressuredifferential HRSG, or flue gas ductwork .




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Committee Statement

CommitteeStatement:

The word "device" is changed to "fan" in all subdefinitions to provide consistency interminology and restricts the definition to fans and not other devices that could causeair or flue gas flow. The technical committee statement is reproduced here for theconvenience of the user: "The committee determined that any reference to pressuredifferential is non-descriptive. Therefore, the definition is revised to the purpose of thefan rather than how it is accomplished."

Committee Input No. 1-NFPA 85-2013 [Section No. 3.3.60.4]




5.3.1.4

All equipment that is associated with pumping, heating, and straining the fuel fromstorage to the service connection shall be designed, sized, and interconnected so as toprovide a suitable fuel supply that meets the boiler design requirements over a fullrange of conditions.




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Unenforceable language was removed to be consistent with action on FR230.




5.3.2.2

Gas piping shall be sized to maintain the desired constant required pressure formaximum burner flow.




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First Correlating Revision No. 10-NFPA 85-2013 [ Section No. 5.3.4.1.2 ]

5.3.4.1.2

The igniter flame or arc shall impinge on the main burner air-fuel mixture and shall supplysufficient ignition energy to provide immediate ignition of all fuel discharge from the mainburner under light-off conditions.




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5.6.3.3 Subsequent Fuel Light-Off — Oil.

When oil is introduced as the second fuel, the light-off cycle for the oil shall accomplishthe following in the listed order:

(1) Place fuel gas flow and airflow control loops in automatic mode.

(2) Satisfy oil fuel system interlocks.

(3) Install oil atomizer.

(4) Open atomizing medium shutoff valve.

(5) Select dual fuel firing.

(6) Set oil control valve in light-off position.

(7) Prove fuel oil control valve in light-off position.

(8) With airflow in automatic mode, gradually bias up airflow by a preset amountcorresponding to fuel input of fuel oil in light-off.

(9) Establish ignition energy in accordance with manufacturer's instructions. Where anigniter is required, see 5.5.2.6.2, 5.5.2.6.2.2, or 5.5.2.6.2.3 for operatingrequirements.

(10) Open oil safety shutoff valves and establish oil flow through the burner.

(11) Gradually remove airflow bias.

(12) Verify stable flame and that the air-fuel ratio is within design limits.

(13) Place the combustion control system into the desired required mode for controllinginput rate of each fuel.

(14) Shut down igniter as required.




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5.6.3.4 Subsequent Fuel Light-Off — Gas.

When gas is introduced as the second fuel, the light-off cycle for the gas shallaccomplish the following in the listed order:

(1) Place fuel oil flow and airflow control loops in automatic mode.

(2) Satisfy gas fuel system interlocks.

(3) Select dual fuel firing.

(4) Set gas control valve in light-off position.

(5) Prove fuel gas control valve in light-off position.

(6) With airflow in automatic mode, gradually bias up airflow by a preset amountcorresponding to fuel input of fuel gas in light-off.


(8) Close the vent valve (where used), open the gas safety shutoff valves, and establishgas flow to the burner.








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5.6.4.3 Subsequent Fuel Light-Off — Oil.

When oil is introduced as the second fuel, the light-off cycle for the oil shall accomplishthe following in the order listed:

(1) Verify that fuel gas flow and airflow control loops are in automatic mode.

(2) Satisfy oil fuel system interlocks.

(3) Install oil atomizer.

(4) Open atomizing medium shutoff valve.

(5) Place oil control valve in light-off position.



(8) Open oil safety shutoff valves and establish oil flow through the burner.



(11) Place the combustion control system into the desired required mode for controllingthe input rate of each fuel.





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5.6.4.4 Subsequent Fuel Light-Off — Gas.

When gas is introduced as the second fuel, the procedure shall be in the following order:

(1) Verify that fuel oil flow and airflow control are in the automatic mode.

(2) Satisfy gas fuel system interlocks.

(3) Place the gas control valve in light-off position.


(5) Establish ignition energy in accordance with manufacturers' manufacturer’sinstructions. Where an igniter is required, see 5.5.2.6.2, 5.5.2.6.2.2, or 5.5.2.6.2.3for operating requirements.

(6) Close the vent valve (where used), open the gas safety shutoff valves, and establishgas flow to the burner.








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6.4.1.2.1* Interlock System.

Figure 6.4.1.2.1 and Table 6.4.1.2.1(a) through Table 6.4.1.2.1(c) show the minimumrequired system of interlocks that shall be provided for basic furnace protection for amultiple burner boiler operated in accordance with this code.

Figure 6.4.1.2.1 Interlock System for Multiple Burner Boiler.

Table 6.4.1.2.1(a) Interlock System for Multiple Burner Boiler

BlockNumber

Action

Block 1

Loss of an individual igniter flame shall cause the following actions:

(1) Close the individual igniter safety shutoff valve(s) and de-energize thespark(s).

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(2) Open the vent valve (fuel gas ignition only).

(3) Signal the main flame protection system that the igniter flame hasbeen lost.

Block 2a1High or low igniter fuel gas header pressure shall be interlocked toinitiate the tripping of the igniter header and individual igniter safetyshutoff valves and de-energize sparks.

Block 2a2Low igniter fuel oil header pressure shall be interlocked to initiate thetripping of the igniter header and individual igniter safety shutoff valvesand de-energize sparks.

Block 2b

Where fuel oil is used for ignition fuel with air or steam atomization,atomizing air or steam pressure out of range shall trip the igniter headerand individual igniter safety shutoff valves and de-energize sparks.

Where direct electric igniters are used, blocks 1 and 2 shall not apply.However, the master fuel trip system shall de-energize sparks andprevent re-energizing until all conditions for light-off have been re-established.

Blocks 3through 13

These blocks represent conditions that initiate the tripping of all mainand ignition fuel supplies through a master fuel trip relay contact(s). Themaster fuel trip relay(s) shall be of the type that stays tripped until theunit purge system interlock permits it to be reset. Whenever the masterfuel trip relay(s) is operated, it shall trip all fuel header, burner, andigniter safety shutoff valves and de-energize all sparks and all ignitiondevices within the unit and flue gas path through master fuel trip relaycontact(s).

Master fuel trip relay contacts shall also trip the fuel oil systemcirculating and recirculating valves. If the design of the fuel oil supplysystem is such that backflow of fuel oil through the recirculating valve isinherently impossible or positively prevented, this valve shall bepermitted to be manually operated and shall not be required to beinterlocked to close automatically on a master fuel trip.

The master fuel trip relay contacts shall also trip primary air fans orexhausters, coal feeders, pulverizers, and coal burner line shutoff valves,or take equivalent functional action to stop coal delivery to burners. The master fuel trip logic shall trip all fuel gas path auxiliary systemsthat introduce hazards through the addition of fuel, oxidizing agents, orignition sources.

Block 3 The loss of all induced draft fans shall activate the master fuel trip relay.

Block 4 The loss of all forced draft fans shall activate the master fuel trip relay.

Block 5Low combustion airflow below the permitted limits shall activate themaster fuel trip relay.

Block 6 (SeeA.6.4.1.2.1 .)

High positive furnace pressure, such as that resulting from a tuberupture or damper failure, shall activate the master fuel trip relay. Highnegative furnace pressure shall activate the master fuel trip relay.

Block 7 Loss of all flame in the furnace shall activate the master fuel trip relay.

Block 8 (SeeA.6.4. 2.3.1 A.6.4.1.2.1 .)

A partial loss of flame that results in a hazardous condition shall activatethe master fuel trip relay.

Block 9 (SeeA.6.4. 2.3.1 A.6.4.1.2.1 .)

When all fuel inputs to the furnace are shut off following a shutdown ofthe boiler for any reason, the master fuel trip relay shall be activated inaccordance with Table 6.4.2.3.1 6.4.1.2.1 (b) or Table6.4.2.3.1 6.4.1.2.1 (c).



Block 10a (SeeA.6.4. 2.3.1 A.6.4.1.2.1 .)

For drum-type boilers, a low drum water level shall activate the masterfuel trip relay.

Block 10b (SeeA.6.4.1.2.1 . )

For once-through boilers, water flow below the minimum specified by themanufacturer shall activate the master fuel trip relay.

Block 11A manual switch that actuates the master fuel trip relay directly shall beprovided for use by the operator in an emergency.

Block 12

The igniter fuel trip shall activate the master fuel trip relay in accordancewith Table 6.4.2.3.1 6.4.1.2.1 (b) or Table 6.4.2.3.1 6.4.1.2.1 (c), if igniterfuel is the only fuel in service or if it is being used to stabilize a mainfuel.

Block 13a

When the fuel gas burner header fuel pressure is above the maximum orbelow the minimum for a stable flame, that fuel shall be tripped. If fuelgas is the only fuel in service, the master fuel trip relay shall beactuated.

Block 13bWhen the fuel oil burner header fuel pressure is below the minimum for astable flame, that fuel shall be tripped. If fuel oil is the only fuel inservice, the master fuel trip relay shall be actuated.

Block 13cThis block represents operation of the fuel oil trip to prevent operationwhen atomizing air or steam pressure is out of range. If fuel oil is theonly fuel in service, the master fuel trip relay shall be actuated.

Block 13dThis block represents the tripping/shutdown of coal-firing equipment thatwill cause a coal fuel trip. If coal is the only fuel in service, the masterfuel trip relay shall be actuated.

Block 14a

Loss of flame at an individual fuel gas or fuel oil burner with one or moreadditional burners operating with stable flames that does not introduce aserious enough condition to warrant a master fuel trip as called for inblock 8 shall close the individual burner safety shutoff valve(s) andassociated igniter safety shutoff valve(s) and de-energize the associatedigniter spark. For gang-operated burner valves, the requirements of

6.6.5.2.1.3(B)(19) and 6.7.5.2.1.3(B)(19) shall be met.

Block 14bOn loss of main coal burner flame, the tripping strategies of 6.8.4 shallbe followed.

Table 6.4.1.2.1(b) Fuel Inputs Shutoff When Class 1 Igniters Are Used

Condition Action Required

(1) First Class 1 igniter(s) fails to light aftersuccessful unit purge. [See 6.6.5.2.1.3(B)(9) , 6.6.5.2.1.3(B)(10) , and 6.8.5.2.1.3(B)(7) .]

(1) Igniter valve(s) shall be closedimmediately. Master fuel trip not required,but a 1-minute delay shall be requiredbefore retrial of that or any other igniter.

(2) Any igniters proven on, all other fuelsources off, all igniter valves subsequentlyclosed.

(2) Master fuel trip shall be actuated.

(3) Any Class 1 igniter(s) proven on, anyburner valve leaves closed limit, all burnervalves subsequently closed, no other mainfuel in service, igniter(s) remain proven.

(3) Associated main fuel gas trip valveand/or fuel oil trip valve shall be closed (fuelgas trip and/or fuel oil trip), proven ignitersshall be permitted to remain in service.

(4) Any Class 1 igniter(s) proven on, anypulverizer startup initiated, all pulverizerssubsequently stopped, no other main fuel in

(4) Proven igniters shall be permitted toremain in service.



service, igniter(s) remain proven.

(5) All igniter and burner valves closed andall feeders or pulverizers stopped.


Table 6.4.1.2.1(c) Fuel Inputs Shutoff When Class 2 or Class 3 Igniters Are Used

Condition Action Required

(1) First Class 2 or 3 igniter(s) failsto light after successful unit purge.[See 6.6.5.2.1.3(B)(9) ,6.6.5.2.1.3(B)(10) , and6.8.5.2.1.3(B)(7) .]

(1) Igniter valve(s) shall be closed immediately.Master fuel trip not required, but a 1-minute delayshall be required before retrial of that or any otherigniter.

(2) Any igniters proven on, all otherfuel sources off, all igniter valvessubsequently closed.


(3a.1) Class 2 igniter(s) proven on,first main burner trial for ignitionfails.

(3a.1) Master fuel trip shall be actuated.

(3a.2) Class 2 igniter(s) proven on,last main burner is taken out ofservice in a normal shutdown.

(3a.2) Associated main fuel gas trip valve and/or fueloil trip valve shall be closed (fuel gas trip and/or fueloil trip), proven igniters shall be permitted to remainin service.

(3a.3) Class 2 igniter(s) proven on,last main burner is taken out ofservice in an abnormal shutdown.

(3a.3) Master fuel trip shall be actuated.

(3b.1) Class 3 igniters proven on,first main burner trial for ignitionfails.

(3b.1) Master fuel trip shall be actuated.

(3b.2) Class 3 igniter(s) proven on,last main burner is taken out ofservice in a normal shutdown.


(3b.3) Class 3 igniter(s) proven on,last main burner is taken out ofservice in an abnormal shutdown.


(4) Any Class 2 igniter(s) proven on,any pulverizer startup initiated, allpulverizers subsequently stopped,no other main fuel in service,igniter(s) remain proven.

(4) (a) If first pulverizer fails to ignite as described in6.8.5.2.1.3(B)(12) , master fuel trip shall beactuated.

(b) If last pulverizer in service is tripped, master fueltrip shall be actuated. (c) If last pulverizer in serviceis taken out of service in a normal shutdownsequence by an operator, proven igniters shall bepermitted to remain in service.

(5) All igniter and burner valvesclosed and all feeders or pulverizersstopped.


Supplemental Information

File Name Description

85_Tables_FCR_25.docx






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Committee Statement

CommitteeStatement:

The correlating committee added the word "header" to block 2b because it appearsto have been omitted from previous editions. The technical committee statement isrepeated here for the convenience of the user: "For once-through boilers, it's criticalto initiate MFT on low feedwater flow as defined by the boiler manufacturer to protectthe boiler "Low furnace pressure" is just as critical as "high furnace pressure" toprotect the furnace, The igniter fuel trip is block 12, not block 11. Therefore thecommittee made the editorial correction and requested staff issue an erratum on thecurrent edition."

Committee Input No. 160-NFPA 85-2013 [Section No. 6.4.2.3.1]


6.5.2.1 Functional Requirements.

The furnace pressure control system shall control the furnace pressure at the desired setpoint in the combustion chamber.




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6.5.2.2.1

The furnace pressure control system, as shown in Figure 6.5.2.2.1, shall include thefollowing features and functions:

(1) Three furnace pressure transmitters (A) in an auctioneered median-select system,each on a separate pressure-sensing tap and with suitable monitoring (B) tominimize the possibility of operating with a faulty furnace pressure measurement

(2) A feed-forward signal (C) to the furnace pressure control subsystem (D),representative which is a function of boiler airflow demand, which can be permittedto be a fuel flow signal, airflow control equipment demand signal, or other index ofdemand, but not demand and is not based on a measured airflow signal

(3) The furnace pressure control subsystem (D), which positions the furnace pressureregulating equipment so as to maintain furnace pressure at the desired set point

(4)

(5) Axial fans, where used, operated in their stable range to prevent uncontrollablechanges in airflow or flue gas flow

Figure 6.5.2.2.1 Furnace Pressure Control Systems Requirements.

* The furnace pressure control protection subsystem (G), which is applied after theauto/manual transfer station (E) to minimize furnace pressure excursions underboth auto and manual operation modes and which includes a feed-forward overrideaction (F) initiated by a master fuel trip in anticipation of a furnace pressureexcursion due to flame collapse and works in conjunction with logic that minimizesfurnace pressure excursions






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Unenforceable language was removed to be consistent with action on FR 151. Thecommittee statement provided by the technical committee is repeated here for theconvenience of the user: "Upon receipt of the Master Fuel Trip (MFT) signal, fuel flowwill go to zero very quickly. The disappearance of the fuel flow-based feedforwardsignal could create additional challenges for the furnace pressure control. Thefeedforward signal is derived from the representative of boiler airflow demand topredict or relate the furnace pressure regulating control element (H) position, usuallythrough the use of a function generator or F(X). "

Committee Input No. 184-NFPA 85-2013 [Section No. 6.5.2.2.1]



First Correlating Revision No. 22-NFPA 85-2013 [ Section No.

6.8.5.1.5.7(C) ]

(C)

Each boiler shall be tested during initial start-up to determine whether any modificationsto the procedures specified in 6.8.5.1.5.7 are required to obtain desired ignition or tosatisfy other design limitations during light-off and warm-up.




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7.5.2.1 Functional Requirements.

The furnace pressure control system shall control the furnace pressure at the desired setpoint in the combustion chamber.




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7.5.2.2.1

The furnace pressure control subsystem, block (A), in Figure 7.5.2.2, shall position thedraft-regulating equipment to maintain furnace pressure at the desired set point.




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First Correlating Revision No. 17-NFPA 85-2013 [ Section No. 7.6.2.1.2.9 ]



7.6.2.1.2.9

The bubbling fluidized bed starting procedure shall be as follows (see 7.6.2.1.2.10 forcirculating fluidized bed):

(1) The bed warm-up burner rate shall not exceed the boiler manufacturer'sspecifications.

(2) Reduced combustion airflow through the bed is permitted for warming up the bedsections. However, in no event shall total air through the unit be reduced belowpurge rate.

(3) Dampers shall be permitted to be closed on bed sections that are not to be fired.

(4) Burners shall be started in accordance with Sections 7.7 and 7.8, as applicable. Ifthe first burner fails to light within the established trial for ignition period afteradmission of fuel, the unit shall be repurged before a second trial.

(5) The bed shall continue to be heated at a rate specified by the manufacturer. Therequired bed level shall be maintained by adding sorbent or inert solids as needed.

(6) Fuel input that necessitates ignition by the bed material shall not be fed into thebed until the average bed temperature for the section being started meets therequirements of 7.6.1.5.1.6.

(7) Warm-up burners shall remain in service until the stable ignition of this fuel hasbeen established.

(8) The duct temperature shall be maintained within the manufacturer's specified limits.

(9) Verification that the fuel is igniting shall be made by watching for a steady increasein bed temperature and a decreasing oxygen level, and the following modificationsshall be made:

(a) Fuel flow shall be increased to maintain bed temperature as necessary.

(b) Airflow shall be increased as necessary to maintain the desired requiredoxygen level.

(c) In the case of solid fuel, if the main fuel has been fed for more than 90 secondsor a period established by the manufacturer without an increase in bedtemperature, solid fuel feeding shall be discontinued until the reason forignition failure is determined.

(10) The active bed area shall be expanded by activating idle bed sections according tosteam load demands by following the manufacturer's recommended sequence.




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First Correlating Revision No. 18-NFPA 85-2013 [ Section No. 7.6.2.1.2.10

]

7.6.2.1.2.10

The circulating fluidized bed starting procedure shall be as follows:

(1) The bed warm-up burner rate shall not exceed the boiler manufacturer'sspecifications.

(2) After the first bed warm-up burner has been placed in service, the bed material andrefractory shall be heated at the manufacturer's specified rate.

(3) Warm-up burners shall be added, if necessary, to maintain the required bed heat-uprate, and the following procedures shall be completed:

(a) Any fans and blowers that were shut down for the warm-up cycle shall beplaced back in service when the bed temperature reaches the requiredtemperature.

(b) Preparation to admit the main fuel shall be made.

(4) Fuel input that necessitates ignition by the bed material shall not be fed into thebed until the average bed temperature meets the requirements of 7.6.1.5.1.6.

(5) Warm-up burners shall remain in service until the stable ignition of the fuel has beenestablished.

(6) Verification that the fuel is igniting shall be made by watching for a steady increasein bed temperature and a decrease in oxygen, and the following modifications shallbe made:

(a) Warm-up burners shall be removed, and fuel flow shall be increased tomaintain bed temperature at the recommended level.

(b) Airflow shall be increased as necessary to maintain the desired requiredoxygen level.

(c) In the case of solid fuel, if fuel has been fed for more than 90 seconds or for aperiod established by the manufacturer without an increase in bedtemperature, solid fuel feeding shall be discontinued until the reason forignition failure is determined.




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Documents

First Correlating Revision No. 1-NFPA 85-2013 [ Section No ... · 3.3.52.1 Booster Fan. A devicefan used to assist in the supply of air to, or the removal of flue gas products