Coal Handling System

importance of coal handling system, necessity and requirement of coal handling system, various transportation means, methods and equipment's, advantages and disadvantages of various methods, coal unloading videos.

1. COAL HANDLING SYSTEM Shaikh Saif

2. Necessity of Coal Handling System A 600MW Power Plant handles about 7200 tons of coals per day. Coal handlings are to be flexible, reliable & capable of handling large quantities in less time than even before. Coal plays a vital role in electricity generation worldwide. Coal-fired power plants currently fuel 41% of global electricity. Shaikh Saif

3. Requirement of Good Coal Handling Plant It should have minimum maintenance It should be simple. It should be reliable Shaikh Saif

4. Coal Handling System Coal Delivery Unloading Transfer Outdoor Storage Covered Storage Inplant Handling Weighing Furnace Firing Preparation / Weighing Shaikh Saif

5. Out-Plant Handling.(Coal Delivery) Out plant handling means transfer of Coal from mine or port to storage of coal at plant site. Transportation by Rail: 4000 to 13000 tons per trip. Transportation by Ships: 45 million tonnes/year Transportation by Roads: Trucks etc. Transportation by belt & conveyors Transportation of Coal by Pipe line. Shaikh Saif

6. Unload of Coal at Site Unload from Rail cars Unloading from Ships Unloading equipment. Self unloading ship. Unloading from trucks (lifting trucks ) Shaikh Saif

7. Rail Car Unloading Rail car unloading featuring bottom dump by unloading bridge. Rail car unloading by means of Rotary Drum Shaikh Saif

8. Bottom Dump Unloading Shaikh Saif

9. Ship Unloading System Self Unloading Ships Unloading Equipment's. Shaikh Saif

10. Self Unloading Ship Shaikh Saif

11. Unloading Equipment's Shaikh Saif

12. Transportation by pipeline Shaikh Saif

13. Transportation through belt & conveyors Transfer of coal by rope, belt & conveyor is also used if the distance between the mines & power station is less than 10 km Conveying capacity was 600 tonnes per hour. The line was 270 meters long, with a vertical rise of 23 meters. It eliminated 115,000 truck journeys. Shaikh Saif

14. Coal Weighing All of our train weighing systems involves "Load Cell" technology which is the only genuinely recognized method of long term accurate & reliable train weighing & uses the exact principal as weighbridges, truck scales & every other general scale is based upon .(onboard coal weighing) Shaikh Saif

15. Coal Storage Storage of coal is undesirable because it costs more as there is, Risk of spontaneous combustion. Weathering. Possibility of loss deterioration during storage. Interest on capital cost of coal lying dormant. Cost of protecting the stored coal from deteriorating & so on. Shaikh Saif

16. Purpose of Storage of Coal To store the coal for a period of 30 – 80 days so that plant is never required to be shut-down. Storage of coal allows the purchaser to take the advantage of seasonal market fluctuation in prices of coal. Shaikh Saif

17. Outdoor Storage (dead storage) The coal is usually kept on ground in the form of pile exposed to outside weather. The coal is required to be protected from deterioration & weathering This is a long term storage i.e. 10% of annual consumption. Shaikh Saif

18. Closed or Live Storage In the closed or live storage the coal is stored for one or two days requirement of the power plant. This storage is used for the purpose of supplying the coal to the combustion equipment with negligible handling T he coal is usually stored in the vertical cylinder bunkers or coal bins. Shaikh Saif

19. Inplant Coal Handling The In-Plant coal handling system deals with feeding of coal from live storage to the furnace. It includes various equipment's for transfer of coal like belt conveyor, screw conveyor etc. & the equipment needed to weigh the quantity of coal for feed. In case of pulverized coal firing system, it requires large no. of equipment’s like chutes, pulverized mills, feeders, weighing machine, hoppers & automatic scales. Shaikh Saif

20. Points to Remember. Simple & sound, requiring minimum operations & transportation. No double handling of coal in plant. Handling unit should be centralized to facilitate inspection & maintenance. Electric motors can be used as driver of mechanism. Working parts should be enclosed to avoid abrasion & corrosion. System should be able to supply required quantity of coal as per demand. Shaikh Saif

21. Coal Preparation Shaikh Saif

22. Crushing of Coal Crushers are used to reduce the coal to optimum size. It is crushed into pieces of 25-30mm for stoker firing and 10-20mm for pulverized coal firing. Shaikh Saif

23. Vibrating Separator Size of vibrating separator is fitted after crusher to screen the coal crushed below set size. Oversized coal is returned to crusher for further proper crushing. Shaikh Saif

24. Transfer of Coal. Different equipment’s of coal transfer. Belt conveyors. Screw conveyors. Bucket elevators. Grab bucket elevators. Flight conveyors or scrapers. Skip hoist. Shaikh Saif

25. Belt Conveyors It consist of endless belt of suitable material running over pair of end drums supported at regular interval by series of rollers(idler). Max Inclination: 20degree. Running Speed: 400-500 RPM. Transport Capacity: 50-100ton/hour over long distance Shaikh Saif

26. Belt Conveyors (cont.) Advantages Low cost & power consumption. Smooth & clean operation. Cheap maintenance. Controlled rate of coal transfer. Shaikh Saif

27. Screw Conveyors It is used for shorter distance(30m). Totally enclosed from atmosphere. Coal dust can also be transferred easily. Diameter: 15-50cm. Speed: 70-120 rpm. Transfer Capacity: 100tons/hour. Shaikh Saif

28. Screw conveyors Shaikh Saif Advantages Cheap Requires small space, simple & tight. Dust tight. Disadvantages High power consumption per ton of coal transfer Wear and tear of screw is high. Shorter life

29. Bucket Elevator Coal is lifted vertical or near vertical direction. It carries the buckets fixed to a chain. B uckets are loaded with coal at bottom & discharges at the top. Shaikh Saif Limitation: The lift of coal is limited to about 30m. Inclination is limited to 60 degree with horizontal Transfer Capacity: 60 tons/hour.

30. Grab Bucket Elevator It lifts & transfer coal on a single rail or track from one point to the other. It can be used with crane or tower. Transfer Capacity: 50 tons/hour Advantages: Requires less power for operation and minimum maintenance. Used when other arrangements are not possible. Lesser operating cost. Disadvantages: Initial cost is high. Shaikh Saif

31. Flight Conveyor or Scrapers It is generally used for transfer of coal when filling of no. of storage bin under the conveyor is required. The coal is discharged in the bottom of trough. Transfer Capacity: 10-100 tons/hour. Advantage: Low capital cost. It can transfer both coal & ash. It can vary easily the rate of coal discharge. Disadvantages: High energy consumption & maintenance cost. High wear and tear due to dragging action. Shaikh Saif

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