Upload
lyndsey-cooper
View
236
Download
0
Embed Size (px)
DESCRIPTION
feeders
Citation preview
Presenting byM. Sai Krishna (Apprentice Trainee)
GRAVIMETRIC COAL FEEDER
contentsDefinition Choosing feederParameter affecting feederTypes of feedersGravimetric feeders principleCoal feeding system in JPLSwitching from gravimetric to volumetricPermissiveProtectionsConclusion
What is Feeder ?? FEEDER: Supplying/providing/regulating/controlling of material to the system.
COAL FEEDER: which Feeds coal from bunker to pulverizes or furnace corresponding to requirement of boiler load.
How to choose a feeder? Type Gravimetric or Volumetric Feeder delivery rate Centre distance between inlet & outlet Size of down spout Type of drive
Parameters affecting FeedersAshSurface Moisture HGIUnit load
Types of FeedersVolumetric Feeders:Feeds on volume basisSimplified controlsNo accuracy Cheaper in comparison to gravimetric feeders Types rotary ,belt, Drag Link Chain, Vibrating Gravimetric Feeders: feeds on weight basis Accuracy performance Stability and Improved Response of Combustion ControlsBalanced fuel/air ratio insure complete combustion.Types Single belt, Dual belt
Rotary coal feeders:Q=V*N*B
Q=quantity of coal feed T/minV=volume of coal transferred per rotation in m3N= speed of feeders in rpmB= bulk density of coal T/m3
Drag link Chain Chain pins Chances of back fire Chain Pins are damage due to uneven coal size Daily maintenance
Use both vibration and gravityUncontrolled recovery of material from top of feeder and feed controlled
Other volumetric feedersScrew feederVibrating feederA rotating helicoid screw moves the material forward or toward the processCapable of dense slurries and dry granular products
Gravimetric feedersSingle belt Load cell O/P * Speed sensor O/P = Rate O/P (Kg / meter) * (meter / second) = Kg / Sec
Another view of feeder
Gravimetric Feeder PrincipleWeighs material on a length of belt between two fixed rollers using a weighing roller.
Belt speed is determined by a tachometer attached to the motor shaft. A microprocessor multiplies the speed and weight signal to arrive at the feeder output.
The microprocessor matches the feeder output to the demanded output by adjusting the feeder motor speed.Calibrating wtLoad cell
Dual Belt Gravimetric Feeder
Feeder Floor17 mts from boiler zero meter
*RAW COAL FROM BUNKERDOWN SPOUTRAW COAL GATERAW COAL GATEFEEDER OUTLET ISOLATION GATEFEED PIPECOAL FEEDING SYSTEM In JPL
Scraper chain
Gravimetric feeder Nomenclature Gravimetric feeder of solid stateFeeder size - 36 inchesCenter distance - 7 feetCapacity-min (17 TPH)and Max(102 TPH)Gear ratio of main drive - 128:1Gear ration of COC 1039.9 : 1Bulk density of coal 0.88 t/mApplicable code NFPA 8503Working pressure - 500 mmwc
Gravimetric Feeder in JPL36 inlet dia
7center distanceWater sprayersDrag chainPA FAN FLOWlightsLoad cellinletDischarge Tension arm
Views of JPL Gravimetric feedersBody shellPneumatic operated gateInlet feeder gateExpansion couplingdischargeLubricant portsSamplecollectingPneumaticairFeeder discharge plugTension arm
Views of JPL Feeders Slotted Tail pulleyClear out beltHalf coupling at head pulleySeal air from PA FAN cold ductWater spray paddle plate
More other pictures of feedersThreaded rodFor belt pulleyTail up rod
Lubricant ports
Causes for Switching to volumetric modeVery Low Load cell OutputVery High Load Cell outputOutput of either Channels of Optical Encoder are not PresentImproper belt tacking
Permission to start feedersPulverizer Ignition PermitNo MFT TripPulveriser Motor ONFeeder SA Damper openFeeder switch in remoteFeeder outlet Gate openPulverizer ReadyFeeder speed minimum JPL interlocks
Protections For FEEDERSFeeder Switch not in remote MFT operatedMill Status offAuto/Manual Stop commandFeeder on >5sec & no coal on beltcurrent not lowPulveriser. Ignition Permit Not available and ignition Support required Feeder SA valve Not OpenDemand signal out of rangeLoss of both tachoBELT motion monitor TIMED OUTFeeder discharge PLUGGEDMaterial on belt in localMotor starter faultRPM deviationNO Material on BELT IN REMOTE CF MONITOR FAULTAIM MODULE BADDIM MODULE BADPIM MODULE BADAOM MODULE BADDOM MODULE BAD
Protections from logicsProtections from Microprocessor Panel
Jpl protections
Conclusion Reduction Fuel consumptionReduction of corrosion in boilerLess built up of slag in boilerGravimetric coal conveyors therefore make for cost-effective boiler operation with minimal coal consumption and reduced emissions.
THANK YOU