[PPT]Boiler Efficiency and Combustion Control - Preferred · Web viewBurner Management Systems...
Transcript of [PPT]Boiler Efficiency and Combustion Control - Preferred · Web viewBurner Management Systems...
Preferred Utilities Manufacturing Corp.
Burner
Management Systems
A Technical Discussion
Preferred Utilities Manufacturing Corp.
Introduction Burner Management System Objectives BMS Design Standards and Definitions BMS Logic BMS Strategies and Hardware
Types of Burner Management Systems BMS Interface to SCADA Systems Summary
Introduction
..a starting point.
Burner Management Systems..
Introduction
What is a BMS? A Burner Management System is defined as the
following: A Control System that is dedicated to boiler safety,
operator assistance in the starting and stopping of fuel preparation and burning equipment, and the prevention of mis-operation of and damage to fuel preparation and fuel burning equipment. 1
1. From NFPA 8501 “Standard for Single Burner Boiler Operation”
Burner Management Objectives
Sequence burner through safe start-up Insure a complete pre-purge of boiler Supervise safety limits during operation Supervise the flame presence during
operation Sequence a safe shutdown at end of cycle Integrate with combustion control system
for proper fuel and air flows
BMS Design Standards Each Burner Management System should be designed
in accordance with the below listed guidelines to control and monitor all sequences of the start-up and shutdown of the burner
National Fire Protection Association (NFPA 8501 /8502 or others)
Industrial Risk Insurers (IRI)Factory Mutual loss prevention guidelines
Each burner management system should be designed to accomplish a safety shutdown in the event of an unsafe condition. (FAIL SAFE)
BMS Design Standards U.S. National Fire Protection Association
(NFPA) Governs safety system design on virtually all boilers
(regardless of the process to be used to combust the fuel) Requires the separation of the Burner Management
System from any other control system Requires the use of a hardwired backup tripping scheme
for microprocessor based systems Requires that a single failure NOT prevent an appropriate
shutdown Factory Mutual loss prevention guidelines.
NFPA 8501
NFPA 8501 Standard for Single Burner Boiler Operation
Single Burner Boilers with fuel input greater than 12.5 mBTU/Hr (Approx. 250 BHP)
Single Fuel or Combination of Fuels (Common being Natural Gas / No.2 Oil / No. 6 Oil)
Simultaneous Firing
NFPA 8502
NFPA 8502 Standard for Prevention of Furnace Explosions / Implosions in Multiple Burner Boilers
Multiple Burner Boilers with fuel input greater than 12.5 mBTU/Hr
Single Fuel or Combination of Fuels including Pulverized Coal
Emphasis on implosion protection (larger boilers with induced draft systems)
BMS Definitions
Furnace Explosions “Ignition of accumulated combustible mixture within
the confined space of a furnace or associated boiler passes, ducts, and fans that convey gases of combustion to the stack”1
Magnitude and intensity of explosion depends on relative quantity of combustibles and the proportion of air at the time of ignition
1. From NFPA 8502 “Prevention of Furnace Explosions / Implosions in Multiple Burner Boilers”
BMS Definitions
Furnace Explosions can occur with any or a combination of the following:1
Momentary loss of flame followed by delayed re-ignition Fuel leakage into an idle furnace ignited by source of
ignition (such as a welding spark) Repeated Light-off attempts without proper purging Loss of Flame on one Burner while others are in operation Complete Furnace Flame-out followed by an attempt to
light a burner1. From NFPA 8502 “Prevention of Furnace Explosions / Implosions in Multiple Burner Boilers”
BMS Definitions
Furnace Implosions More common in large Utility Boilers Caused by any of the following:
» Malfunction of equipment regulating boiler gas flow resulting in furnace exposure to excessive induced draft fan head capability
» Rapid decay for furnace gas temperature and pressure due to furnace trip
1. From NFPA 8502 “Prevention of Furnace Explosions / Implosions in Multiple Burner Boilers”
BMS Basic Definitions
Common Terminology Supervised Manual
» Manual Burner Lightoff with Interlocks Automatic Recycling (Single Burner Only)
» Automatic Burner Start and Stop based on preset operating range (ie.. Drum pressure)
Automatic Non Recycling (Single Burner Only)» Automatic Burner Start and Stop based on Manual
command to start.
Types of Flame Scanners Infrared (IR) Detectors
Single Burner Applications More Suitable with Oil Burning Flames
Ultra-Violet (UV) Detectors Multiple Burner Applications More Suitable for Gas Burners and Combination Gas /
Oil Burners Self Check Scanners
Flame Signal is interrupted at set intervals to verify proper operation of scanner
Single Burner BMS Inputs
OIL
GAS
STEAM
FEEDWATER
PSL
TSLTSH
PSL
High Steam Pressure (D )
Low Low Drum Level (D )
PSL PSH
PSL
ATOMIZINGMEDIUM
FuelGas
PressLow
(D )
FuelGas
PressHigh
(D )
FT
FT
AtomizingMediumPress Low (D)
Fuel Oil Flow (A)
Fuel Oil Temp High (D )
Fuel Oil Temp Low (D )
Atomizing Medium Flow > Min (D )
Fuel Oil Press Low (D )
PSH
PSL
FT
PSHPT
LSLL
LSLL
Purge Purge Air Flow (D)
Minimum Air Flow (D )
AE TE
(D) - Descrete Signal Used By Flame Safeguard System
Common Alarm Output (D)
Remote Annunciator(By Others)
Safety Shut Off &Vent Valves
Control Valve &Shut Off Valve
Safety Shut OffValves
ControlValve
ControlValve
Safety Shut Off& Vent Valves
IGNITERGAS
Flame / No Flame (D )
FS
FD F A NHAN D OF F AUT O
Li m i t s M adeHol d t o Purge
S C R L M O D ER E S E T
F UE L SE L ECTGAS OIL
BUR NEROF F ON
BMS Logic
Burner Management Systems can be broken down into “Interlock Groups”
Typical BMS Interlock Groups: Boiler Purge Igniter Header Valve Management Main Fuel Header Valve Management MFT (Master Fuel Trip) Logic
Purge InterlocksBOILE R TR IPP ED
A ND PURGE / RESET PB
S TA RT F D F A N
A ND
PERMISS IV ES S ATIS FIED : - M A IN F UE L V A LV E S CLO S E D - NO F LA M E P RE S E NT - FD FA N RUNNING - M INIM UM A IR F LO W S W ITCH M A DE - W A TE R LE V E L S A TIS F A CTO RY - A TO M IZING M E DIUM O N - FUE L S UP P LY P R E S S U RE NO T LO W
E NE RGIZE F UE L RE LA Y
P URGE S IGNA L TO C C S
NOT A ND
S TA RT-UPTIME R
A NDP URGE A IR
FLOW SW ITC HMA D E
F D D A MP E R INFULL OP E NP OS ITION
P URGE TIM E R S E T
P URGE C OMP LE TE
RE MOV E P URGE TO C C S SYSTEM TR IP
Y E SNO
Igniter Interlocks
A ND
E NE RGIZE IGNITE R A NDIGNITE R HE A D E R V A LV E S
NOT
SYSTEM TR IP
P URGE C OM P LE TE
A IR D A M P E R IN LOW F IREP OS ITION
FUE L V A LV E IN LOW F IREP OS ITION
10 S E C OND D E LA Y
F LA MEP ROV E N
10 S E C P ILOT TRIA LF OR IGNITION
TIM E R C OM P LE TE
A ND
P E RM IT F OR M A INF LA M E
Main Flame Interlocks
A ND
NOT
SYSTEM TR IP
IGNITE R TIM E RC OM P LE TE
F LA M EP ROV E N
10 S E C M A IN F LA M ETRIA L
TIM E R C OM P LE TE
A ND
RE LE A S E TOM OD ULA TE TO C C S
E NE RGIZE M A INF UE L V A LV E S
D E -E NE RGIZEIGNITION
C OM P O NE NTS
Single Burner Main Fuel TripFOR OIL: - LOW FUEL PRESSURE - LOW TEMPERATURE (HEATED OILS) - LOSS OF COMBUSTION AIR - LOSS OF FLAME OR FAIL TO ESTABLISH - LOSS OF CONTROL SYSTEM ENERGY - POWER FAILURE - LOW WATER LEVEL (AUX LEVEL CONTACT) - LOSS OF ATOMIZING MEDIUM - EXCESSIVE STEAM DRUM PRESSURE - HIGH OIL TEMPERATURE (HEATED OILS)
TR IP B OILER
FOR GAS: - LOW FUEL GAS PRESSURE - HIGH GAS PRESSURE - LOSS OF COMBUSTION AIR - LOSS OF FLAME OR FAIL TO ESTABLISH - LOSS OF CONTROL SYSTEM ENERGY - POWER FAILURE - LOW WATER LEVEL (AUX LEVEL CONTACT) - EXCESSIVE STEAM DRUM PRESSURE
OR
OR
TR IP IGN ITER,IGNITER VALVES,
OPEN IGN ITERVENT
TRIP MAIN FUELVALVES, OPEN
VEN T VALVE(GAS ON LY)
FU EL CON TROLVALVE TOCLOSED
POSITION
TRIP MFT R ELAY
BMS System Types
Early Burner Management Systems Hardwired Systems Solid State Systems
Microprocessor Based Systems Fireye E110 / Honeywell 7800 series with fixed
Logic. PLC Based Systems
Programmable Logic Controller (PLC) Based Powerful, versatile, expandable, more reliable.
Early Burner Management Systems
Hardwired Systems Relay and Timer Driven. Found on older
installations Typical of Late 50’s, 60’s
Solid State Systems Solid State Processors and Relays Found on Systems provided in the 70’s and 80’s Proprietary Hardware (ie.. Forney and Peabody) Spare Parts are extremely hard to find.
MicroProcessor Based Systems
Microprocessor Based System providing: Burner Sequencing Ignition Flame Monitoring
Fixed Program with Limited Configuration Changes
Components Selected Based on Requirements Programmers, Flame Amplifiers, Message Displays
FLAM ESC AN N ER
FIE LD W IR IN G
Fireye™ BMS Layout
A U T O M A T IC P R IM AR Y S A FE TY C O N T R O L
AM P LIF IE REP PR O G R AM M ER
FIELD W IR IN G
MicroProcessor Capabilities
Simple, Cost Effective Features
Selectable Flame Amplifiers / Scanners Remote Display Remote Data Communications via Modbus Port Modernization kits are available to integrate with older
systems Spare Parts Normally Readily Available
When These Systems are Used
“Simple” Boiler Installations Packaged Firetube / Watertube Boilers (Steam /
Hot Water) Single Burner One Fuel at a Time No Flue Gas Re-Circulation Upgrades from Previous MicroProcessor Based
Systems
PLC Based Burner Management Systems
PLC Based Features NFPA 8501, 8502 Watchdog timer UL 508 Certification
Redundant Scanners Logic+ Message Center
Shows program status Displays alarms Prompts operator
Each PLC based burner management system should incorporate a number of design techniques which help detect and act upon unsafe failure modes which can occur in any microprocessor based system. These design features include the following:
Critical Input Checking Critical output channel monitoring Electro-mechanical Master Fuel Trip (MFT) Relay Redundant Watchdog Timers Low Water Cut-out Monitoring During Blow Down
PLC System Basic Design Features
PLC Based System Capabilities
Provision for Multiple Fuel Firing Capped gas input during curtailment Changeover from gas to oil at any load Simultaneous firing of waste and fossil fuels
Redundant Scanners, change scanner with fuel Single or Multiple Burner Applications Integration of BMS with SCADA
PLC Based Operator Interfaces
Features Clear Written Messages to indicate status,
required operator interaction, trip/alarm indication High Visibility through two lines of display Messages reduce time consuming troubleshooting Prioritizes Messages
» First Out Alarms» Warning / Alarm Messages» Status Messages / Prompts Operator
PLC System Layout (Typical)
Logic+ M essageD isplay
S W IT C H S IL E N C E L IG H T
D oor M oun ted L ights / P ushbuttons
FLAM E A M P LIF IE R(S ING LE /
RE DU N D AN T)
FIE LD D E V ICE S
PLC CPU I/O I/O I/O I/O
I/O EXPANSION I/O
CO M B U S TIO NC O N TR O L SYS TEM
Benefits of PLC Based Systems
Flexibility / Reliability Programming Software allows changes to
system Choice of PLCs
GE / Modicon / Allen Bradley / Koyo Choice of Flame Scanners
PPC / Fireye / Honeywell / Iris / Coen Application Specific Quantity of Burners / Fuels is not restricted
When to Use PLC Based Systems
“Complex” Boiler Installations Larger Packaged Units / Field Erected Units Multiple Burners Multiple Fuels, On-line Fuel Changeovers Flue Gas Re-Circulation Replace Existing Relay Logic Systems Requirement to maintain consistent control
platform (spare parts, etc..)
BMS SCADA Interface
BMS Systems can be integrated into a SCADA System Allows Remote Monitoring of Flame Status Allows Remote Control of BMS Events (ie.. Burner trip) can be routed to
Historical Portion of SCADA for fault evaluation
Burner Operation can be trended over time
BMS SCADA Interface
Interface Methods:
PLC CPU I/O I/O I/O I/O
C om m unica tionIn terface
(If N ecessary)
M O D B U SC O M M U N IC A TIO N
P R O TO C O L
M O D B U SC O M M U N IC A TIO N
P R O TO C O L
BM S LO G IC + S YS TEM
SC A D A P C
FIR EY E E 110 S Y S TE M
BMS SCADA Interface
Summary
Benefits Associated with New Burner Management Systems Help Improve plant safety Help qualify for reduced insurance cost Reduce Startup and Down Time with
comprehensive alarming and diagnostics
Summary
Review of Topics Discussed Objectives of Burner Management Systems BMS Design Considerations Basic BMS Logic Types of Burner Management Systems How BMS Systems can be integrated with
Plant Wide SCADA Systems
Preferred Utilities Manufacturing Corp
For further information, contact...
Preferred Utilities Manufacturing Corporation31-35 South St. • Danbury • CT
T: (203) 743-6741 • F: (203) 798-7313www.preferred-mfg.com