Coal Handling Plante‐Learning Series Damodar Valley Corporation Introduction Coal Handling Plant The purpose of the Coal handling plant in a thermal power plant is to Process raw coal & insure against the irregular supply of coal which is dependent on many players in the Supply chain The function of a CHP is to receive, process, store ,feed the Coal bunkers consistently over the entire life of the Power plant. Coal is received from mines in the form of lumps, the sizes varying from 100mm to 350mm, in two types of wagons through Rail; BOBR meaning Bogie Open Bottom Rapid discharge & BOXN meaning Bogie Open High Sided Side discharge Wagon BOBR wagons are unloaded in Track Hoppers & BOXN Wagons are unloaded by Wagon tipplers. Coal is then supplied to the crusher house through Roller screens or Vibrating feeders to sieve the coal before feeding to the crusher; 20% of the coal that is received is already <20mm size so this is separated & only larger lumps are fed to the Crusher The crusher breaks the lumps to sizes<20mm which is the input size to the coal Pulverizers Introduction Coal Handling Plant The crushed coal is fed to the conveyors in the crusher house through Belt feeders; Coal is either directly fed to the coal bunkers or to the Stacker/Reclaimers for stocking when the bunkers are full; The stacking is done to insulate the plant against the erratic supply of coal; CERC allows stocking of 1 ½ months stock of coal for Pit head plants In case of non receipt of wagons the coal from the stock pile is reclaimed through the Stacker/ Reclaimers & fed to the coal Bunkers To increase redundancy certain Plants also have Emergency reclaim Hoppers near the Crushed coal Stock pile where the dozers are used to feed coal to the bunkers when the Reclaimers breakdown. Coal is conveyed by means of conveyor Belts in the coal handling plant Typical Coal Flow Diagram .CHP Coal Handling Plant . Typical Layout of a CHP Coal Handling Plant Crusher House S&T Control Room TRACK HOPPER PH STOCKYARD DS Pump House STOCKYARD CHP Control Room STOCKYARD STOCKYARD CHP Pump House M CR o C om CP H . Side Arm Charger Track Hopper Stacker Re-claimer Paddle Feeder Apron Feeder Hydraulics for S/R. PF Crusher LT Switchgear PLC System VVVF Drives Locomotive & Pay loaders . WT.Key Equipments in CHP Coal Handling Plant Wagon Tippler. SAC. Weigh Bridge (In-motion Pit-less) Coal Handling Plant Purpose : To weigh the coal wagons on receipt before unloading into the Track Hopper . Types of Wagons Coal Handling Plant BOXN wagons unloaded through Wagon Tipplers BOBR wagons unloaded through Track Hoppers . Typical GA of Wagon Tippler Coal Handling Plant . Wagon tippler & Side arm charger Coal Handling Plant WT Control Room Dust Suppression system Side Arm Charger Wagon Tippler Coal Discharge direction . Wagon tippler Coal Handling Plant Purpose: To dump coal from BOXN wagons into the underground hopper from where it is transported to the Crusher House.e. 20 wagons can be unloaded from the Wagon Tippler . Typical unloading cycle for wagons is approx 3 min i. Apron Conveyor/Feeder Coal Handling Plant Purpose: to reduce direct impact on the conveyor below the Wagon tippler . Apron Conveyor/Feeder Coal Handling Plant . Side Elevation of Track Hopper Coal Handling Plant . Sectional elevation of Track Hopper Coal Handling Plant . A rake of 58 Wagons could be unloaded in 3 placements in a250m TH within 2 1/2 Hrs .Track Hopper Coal Handling Plant Purpose: For unloading Coal from BOBR(Bogie open Bottom Rapid discharge) Wagons to Hoppers underneath. This system is preferred to the Wagon tippler as the evacuation time is less (2 ½ Hrs compared to 5 Hrs for Wagon tippler). . when not in use they are parked on either side. generally two feeders are provided on each side within a Track hopper .Paddle Feeder Coal Handling Plant Track Hopper Coal Tray Curved Paddle Blades Table Wheels for movement of the Paddle feeder Impact Idlers Impact Idlers Cable reeling drum Cable reeling drum Purpose: to scoop the raw coal from the table below the Track hopper to the respective conveyor. Paddle Feeder Coal Handling Plant Curved Blades Cable reeling Drum Idlers Table Conveyor . Grizzly Feeder/Vibrating Screen Coal Handling Plant Vibrating Screen . .Roller Screen Coal Handling Plant Purpose: Sieving the coal to reduce unnecessary loading on the Crusher. By sieving. the smaller particles (<20mm) are directly fed bypassing the crusher. typically 75‐80% of the coal received goes to the crusher Drive motors for the Rollers .Roller Screen Boiler Tube Failures Coal <20 mm size is collected in this hopper & fed on the crushed coal conveyor after the crusher. typically 20‐25% of ROM is collected in this hopper Coal >20mm is now fed to crusher . Ring Granulator Coal Handling Plant Purpose : To crush Raw coal (size 350mm) to < 20mm size which is stored in coal bunkers to be fed to Coal Pulverizers. . Ring Granulator Coal Handling Plant . .Belt Feeder Boiler Tube Failures Drive Pulley Generally used for feeding the coal from the crusher to the conveyors. these are used to increase the redundancy/flexibility of the conveying system. Stacker/Re-claimer Coal Handling Plant Purpose: To stack the coal after filling the bunkers for future use & reclaim the coal when the coal supply is irregular . Bucket Wheel Stacker/Re-claimer Coal Handling Plant Bucket wheel for reclamation Operators Cabin Counter Weight Carriage Rail Conveyor Belt . Typical Conveyor Belting System Coal Handling Plant Purpose: To convey Coal continuously between the Transfer Points & ultimately to the coal storage silos. . Typical Conveyor gallery Coal Handling Plant Purpose: For providing weather proof housing & maintenance space for the conveyor belting . Conveyor Belt Boiler Tube Failures Conveyor Idlers . the prime mover is a motor attached through Fluid coupling so that the starting current of the motor is restricted. Pulley Plummer Block Drive Shaft Rubber Lining .Conveyor Pulley Boiler Tube Failures These are the drivers of the conveyor Belts. they reduce the impact on the conveyor belts thereby increasing longevity. they are the supporting rollers for the conveyor belt on which the coal laden conveyor belt glides. generally used on the tables of the paddle feeders in Track Hoppers or under the coal chutes. Normal conveyor Idlers .Conveyor Idlers Coal Handling Plant Impact idlers. . Removal/Detection of Metal Particles Coal Handling Plant ILMS : Inline Magnetic Separator Remove tramp iron & other magnetic materials Metal detector Detect non magnetic metal pieces & heavy iron pieces . PAY LOADER Coal Handling Plant Purpose : to stack coal in the stockpile area to be reclaimed by the Stacker/Re‐claimer . The unsettled dust is sucked through fans installed on the roof through bag filters or cyclonic separators & the heavier dust particles are fed back to the bunkers • . The water is sprayed in conjunction with compressed air & these particles adhere to the dust & settle down • Dust Extraction system: This is used in Bunker silos where the coal is fed from conveyors & falls from a height.Dust Suppression Coal Handling Plant As the coal Handling plant is prone to fugitive dust it is mandatory to install dust suppression systems in the CHP • Spraying system: sprinklers are used in the stockpile area to suppress the dust . fine atomic particles of water are sprayed on the stock pile & this acts as a blanket • DFDS: dry fog dust suppression system: this is used typically at transfer points & hoppers. the mechanism is simple. Dust Extraction System Coal Handling Plant . 490 Mt .Coal Trivia Coal Handling Plant • • • • • • • Coal provided the energy which fueled the Industrial Revolution of the 19th Century and also launched the electric era in the 20th Century Coal provides 26.5845Mt (2008e) Primary source of energy for India.5% of the world's electricity Total Global Hard Coal Production .5% of global primary energy needs and generates 41. third largest producer of coal Commercial coal Mining in India started in 1774 in Raniganj coal field by M/S Sumner & Heatly of East India Company Indian Coal production . accounts for 55% of Energy need Hard coal reserves of India 246 bn Tonnes & proven reserves of 92 bn tonnes. Grades of coal Coal Handling Plant . Coal Handling Plant Thank You .