BURNER MANAGEMENT SYSTEM

Authorised BySANTOSH BHARADWAJ REDDYEmail: help@matlabcodes.comEngineeringpapers.blogspot.com

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INTRODUCTION :The problem of operation and safety posed by a Recovery Boiler is much more than a conventional utility/Industrial Boiler. It is basically a chemical recovery process unit where the organic material in the black liquor is burnt, while the sodium salt is reduced and drained as molten smelt from the furnace bottom. At the same time, the heat released is utilized for steam generation. Though predominantly the heat for the process is obtained from the burning of the black liquor, supplementary heat from oil fired auxiliary fuel burners is required to start up the unit, regulate the charbed , avoid blackouts and to augment additional steam.

FEATURES :Auxiliary fuel system is comprised of one level of starting burners (4 burners Oil fired with oil ignitors) at the hearth and one level of load carrying burners at the secondary(famous)air registors. The BMS provides for the proper sequencing of equipment during the normal startup operating and shut down procedures and provides for an auxiliary fuel trip and/or an alarm during an adverse burner or unit operating condition. This is accomplished through the use of pre-wired logic and various Interlocks.

FUNCTION :The following operations of the function are achieved in the BMS.

1. Boiler purge.2. Main oil header trip valve open/close operation.3. Ignitor oil header trip valve open/close operation.4. Auxiliary fuel burner ignitor ‘ON/OFF’ operation.5. Ignitor Flame scanning.6. Auxiliary fuel burner start/stop operation.

7. Auxiliary fuel trip production.8. Emergency drain trip protection. The BMS is a local-manual relay system. Starting burners are started and stopped locally from their associated local switch boxes while the various header trip valves are opened and closed remotely from associated Push Buttons on BOILER CONTROL DESK(BCD).All the commands of BMS are given from BCD and all the feed-back from BMS are indicated in BCD.

FURNACE PURGE :Before any auxiliary fuel can be introduced in the unit(initial or after an auxiliary fuel trip)a satisfactory furnace purge cycle must first be completed. To start a furnace purge cycle, proceed as follows:1. Establish an (I.D. Fan Start,Permissive)by completing all of the

following conditions.*1A. All Emergency drain valves are closed.*1B. Main oil header trip valve and ignitor trip valve closed.*1C. Feed Water shut off valve is open.1D. Evaporator outlet temperature less than 525oF.1E. Precipitator outlet temperature less than 525oF.(*) Conditions preceded by an asterish are not required once the ID fan is running.2. Place I.D. Fan in service.3. Place the F.D. Fan in service.4. Adjust the primary air flow to maintain a minimum of 30% of full load air flow.5. See that all of the starting and all of the load carrying burner valves are fully closed.6. Reset the boiler trip by depressing the BOILER TRIP RESET Push Button.7. When the purge ready light comes on indicating that all of the purge requirements have been completed depress the PURGE START PUSH BUTTON.

TRIP VALVE OPERATION :

MAIN OIL HEADER TRIP VALVE:

Depressing the main oil header trip valve open push button once the furnace purge is completed, will open the main oil header trip valve.

Depressing the main oil header trip valve close push button will close the main oil header trip valve.

IGNITOR OIL HEADER TRIP VALVE :

Depressing the Ignitor Oil Header trip valve open push button once the purge cycle has been completed and the main oil header trip valve is fully opened, opens the ignitor oil header trip valve.

AUXILIARY FUEL START :-STARTING BURNERS:

Prior to placing a starting burner or load carrying Burner in service the operator must see the following condition s are established.

1. Ignitor oil header trip valve is fully opened.2. The associated oil gun of each starting burner to be placed in service

is properly engaged in the firing position.3. The oil temperature is above a minimum of 160oF.4. Manual atomizing steam valve opened to establish a minimum of 5

Psi steam to oil differential pressure at each gun.5. Manual oil shut off valve open at each gun.6. Fuel air damper open.7. Ignitor in engaged position.

When the above mentioned conditions have been established ,an individual starting burner or load carrying burner may be placed in service at its local control station as follows:

1. Turn the associated starting burner local control switch to the IGNITE position. This will place the ignitor in service by opening the ignitor oil and air valves and energizing the ignition transformer.

2. When the ignitor proves flame, indicated by the associated “Flame” light coming on release the starting burner local control switch to the “OPERATE” position. This will arm the holding coil of the associated Burner manual reset valve.

3. Place the burner in service, by first opening the manual reset trip valve. When the trip valve has been fully opened, slowly open the manual shut off valve and establish flame by visual observation.

OPERATION (SHUT DOWN)AUXILIARY FUEL SHUT DOWN:

STARTING BURNER & LOAD CARRYING BURNER An orderly shutdown of an individual burner takes place by turning the associated starting burner local control switch to the TRIP GUN POSITION which will close the burner shut-off valve. This will leave the associated ignitor in service for manually scavenging the gun as follows:1. Open the associated steam scavenge valve and scavenge the gun.2. After scavenging for approximately one minute close the steam

scavenge valve.3. Close the manual atomizing steam valve.4. Place the associated burner local control switch to the OFF

position,this will shut down the ignitor.5. Retract the oil gun from the firing position. However, it must be noted

that following a fuel trip the guns shall not be scavenged.Any one of the following conditions being present, results in the automatic shutdown of the burner oil gun:*1. Associated ignitor fails to prove flame.*2. Ignitor Oil Header trip valve not fully open.*3. Auxiliary fuel trip.4. Oil temperature below 160oF.5. Steam to oil differential pressure below 5 PSIG.6. Associated Oil gun not engaged in the firing position.(*) Any of the conditions preceded by an asterisk will also trip the associated ignitor.

AUXILIARY FUEL TRIP.:Any one of the conditions below will cause an auxiliary fuel trip to occur,and results in the immediate shutdown of all of the auxiliary fuel in service and necessitates completion of another furnace purge cycle before any auxiliary fuel firing may be reinstated.1. Evaporator outlet temperature greater than 525oF.2. Precipitator outlet temperature greater than 525oF.3. I.D. Fan not in service.4. F.D. Fan not in service.5. Primary Air Flow less than 30% of full load of flow.6. Furnace pressure greater than +4”W.G.

7. Ignitor oil pressure not within controlled limits.(75% to 125% of full load pressure).

8. Ignitor air pressure greater than 75% of full load pressure.9. Main oil pressure below 75% of full load pressure.10. Starting burner oil header pressure above 125% of full load pressure.11.Load carrying burner oil pressure above 125% of full load pressure.12.Recirculation selector switch not in OPERATE position.13.A Boiler trip condition exists.14.Either of the local auxiliary fuel trip push button depressed.15.Both of the auxiliary fuel trip push buttons on the BCD depressed.

EMERGENCY DRAIN AND TRIP :An emergency drain and trip procedure is initiated if water in any amount is known to be entering the furnace and cannot be stopped immediately or if any leaks external to the furnace such as failure of gaskets, gage glasses etc.An emergency drain is initiated by simultaneously depressing the two “Emergency Drain push button” on the BCD panel.An emergency drain trip initiates the following.*1. Auxiliary fuel trip.*2. F.D.Fan trip.3. Closing of the feed water valve.4. Opening of the emergency drain valve.

* Conditions preceded by an asterisk are the same trip inputs .

BOILER TRIP :Depressing the two emergency drain push buttons results in an instantaneous boiler trip. The feed water supply valve will not close, however, until the following conditions are also satisfied.

1. All trip valves closed OR2. Ignitor trip valve closed and

All oil scanner valves closed.

The emergency drain valves should not open until the feed-water valve is closed (This is an externally interlocked circuit).The emergency drain condition will remain, “Scaled in ” until the circuit is reset by means of a reset push button on the BCD panel. This action is to be taken by responsible personnel after assessing the particular situation which warranted the emergency drain trip initially.

Alarms :The following alarm conditions will cause an annunciator alarm to sound if the appropriate terminals on the BCD panel are connected to the customers annunciators. The contacts are normally open for the alarm conditions.

1. Furnace pressure greater than +4”W.G.2. Air flow less than 30%.3. Ignitor oil pressure less than 75%.4. Ignitor air pressure less than 75%.5. Main oil pressure less than 75%.6. Starting Burner Oil pressure greater than 125%.7. Boiler trip.8. Auxiliary fuel trip.9. I.D. Fan not running.10.F.D. Fan not running.11.Precipitator outlet temperature greater than 525oF.12.Feedwater shut off valve not open.13.Emergency drain valves not closed.14.Evaporator outlet temperature greater than 525oF.15.Emergency drain and trip.

ECONOMIZER: In boilers, economizers are heat exchange devices that heat fluids,

usually water, up to but not normally beyond the boiling point of that fluid.

Economizers are so named because they can make use of the enthalpy in fluid streams that are hot, but not hot enough to be used in a boiler, thereby recovering more useful enthalpy and improving the boiler's efficiency. They are a device fitted to a boiler which saves energy by using the exhaust gases from the boiler to preheat the cold water used to fill it (the feed water).

DIGITAL I/P’s :1. OIL GUN ENGAGED2. HOBV CLOSED3. SCNR FLM4. IGNITOR5. FURNACE PRESSURE6. HO PRESSURE7. ATOM STEAM PRESSURE8. HO TEMPERATURE9. HORV OPEN10.HORV CLOSE11.HOTV OPEN12.HOTV CLOSE13.EP O/L TEMP14.AIR FLOW15. DRUM LEVEL16. SA/TA FAN RUNNING17. ID FAN RUNNING18. PA FAN RUNNING19. FW SHUT OFF VLV OPEN20. FW SHUT OFF VLV CLOSE21. EMERGENCY TRIP22. EM DRAIN & TRIP23. AUXILIARY FUEL TRIP24. PURGE START25. SCANNER FAN-A ST/SP26. SCANNER FAN-B ST/SP

DIGITAL O/P’s :1. ATOMISING STEAM V/V2. HOBV OPENED3. SCAVENGE V/V4. HEA IGNITOR5. HOTV OPEN CMD6. HOTV CLOSE CMD7. HORV OPEN CMD8. HORV CLOSE CMD9. SCANNER FAN-A START10.SCANNER FAN-B START11.NO BOILER TRIP12.SA/TA FAN START PMT13.PA FAN START PMT14.ID FAN START PMT15.BL PMP16.EP ASH PUMP17.AFT18.PURGE COMPLETE NO AFT19.EP O/L TEMP20.FW SHUT OFF V/V CLOSE21. TRIP SA/TA FAN22.TRIP PA FAN23.STM-BL V/V24.STARTUP V/V25.EMRG DRN V/V

PLC used in BMS :

HONEYWELL 620LCS AND MOELLER IPC620 PLCSPowerful, modular easy to use system with a vast range of expansion options

Honeywell 620LCS - Moeller IPC620

The Honeywell 620LCS is an extremely versatile, modular PLC system offering high speed control of both discrete and analogue applications.Also marketed by Klockner-Moeller as the IPC620PLC, the system features many special purpose modules for enhanced network communications and functionality. The 621 series universal I/O expands the 620 to build systems of up to 2040 I/O points in any mix of analogue or digital.CNC & PTP applications are handled by the Honeywell 622 motion control system which integrate seamlessly into the 620 rack to give up to 6 axis of servo control.The entire 620 range is programmed using the 623-60 loader suite which has a comprehensive instruction set including full floating point maths and user definable function blocks. Pre-tested function blocks are also available to download. WinLoader, a windows based version of the programming suite is now available for use with Windows XP.

uses

PLC used is TATA HONEYWELL. CPU : IPC 620-35. SOFTWARE : 620 WINLOADER,VERSION 5.4 DC POWER SUPPLY DI’S : 352, DO’S : 512. INPUT : 110V/220V or 240V,5.5A Max. OUTPUT : 25V DC,20A. FREQUENCY : 50 HZ. PLC SPECIFICATIONS :- 32K EXPANDABLE MEMORY. PLC used is a Redundant System. I/O Handling Capacity : 2048 Real IO’s. Scan Rate : 50msec.

PLC consists of 5 Modules:• Memory module• Register module• System Control module• Processor module• I/O Control module. The PLC is Redundant type. Redundant system has Running mode and Standby mode slots. If Running mode won’t work then Standby mode is used by PLC for

functioning.

A Key is present in the PLC.• It has four modes:1. Program 2. Disable3. Run/Prog.4. Run

INDUSTRIAL SPECIFICATIONS :

• FURNACE TEMP. : 600deg.C(inlet),650deg.C• FURNACE STEAM: 35TPH• ECONOMISER TEMP. :

380deg.C(inlet) , 160deg.C(outlet)• ESP TEMP. : 160deg.C(inlet),150deg.C(outlet)• STEAM DRUM WATER LEVEL : 54%• SUPER HEATED STEAM TEMP. : +/- 410 deg.C • CHIMNEY TEMP. : 140 - 150 deg.C • GREEN LIQUOR OUTLET : 1000 TPH/DAY• STEAM PRESSURE O/L : 36kg/cm2• STEAM TEMP. O/L : 410 – 415 deg.C • STEAM FLOW O/L : 36 TPH.

Conclusion:-

• The main theme of this project is Purging the Furnace at initial stage and activating the Emergency Trip and Drain valves during abnormal conditions while continuous running of process.

• This project can be used for better functioning of Boiler plant without any malfunctions by continuously monitoring the Industrial parameters and protecting the Boiler from destruction

• Authorised By• SANTOSH BHARADWAJ REDDY• Email: help@matlabcodes.com• Engineeringpapers.blogspot.com

• More Papers and Presentations available on above site