Shaikh Saif

COALHANDLIN

GSYSTEMBy: Shaikh Saif

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

REQUIREMENT OF GOOD COAL HANDLING PLANT

It should have minimum maintenance It should be simple. It should be reliable

Shaikh Saif

COAL HANDLING SYSTEMCoal Delivery

Unloading

Transfer

Outdoor Storage

Covered Storage

Inplant Handling

Weighing

Furnace Firing

Preparation / Weighing

Shaikh Saif

OUT-PLANT HANDLING.(COAL DELIVERY)

Out plant handling means transfer of Coal from mine or port to storage of coal at plant site.

1. Transportation by Rail: 4000 to 13000 tons/trip.2. Transportation by Ships: 45 million tons/year.3. Transportation by Roads: Trucks etc.4. Transportation by belt & conveyors.5. Transportation of Coal by Pipe line.

Shaikh Saif

FACTS Daqin Railway coal trains—20,000 t, 3.2 km, 210

wagons(China). The longest train there was recorded in 1986, carrying

Kuzbass coal in 439 cars, for the train length of 6500 meters and total weight of 43,500 tonnes (Russia).

one litre of fuel moves 24 ton/km on road, 85 ton/km on rail and 105 ton/km on water.

Shaikh Saif

UNLOAD OF COAL AT SITE

Unload from Rail cars Unloading from Ships1. Unloading equipment.2. Self unloading ship.o Unloading from trucks (lifting trucks)

Shaikh Saif

RAIL CAR UNLOADING Rail car unloading featuring

bottom dump by unloading bridge.

Rail car unloading by means of Rotary Drum

Shaikh Saif

SHIP UNLOADING SYSTEM

Self Unloading Ships

Unloading Equipment's.

Shaikh Saif

TRANSPORTATION BY PIPELINE

Shaikh Saif

Ultra-high-molecular-weight polyethylene

TRANSPORTATION THROUGH ROPE & 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

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

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

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

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

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

The coal is usually stored in the vertical cylinder bunkers or coal bins.

Shaikh Saif

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

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

COAL PREPARATION

Shaikh Saif

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

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

TRANSFER OF COAL.Different equipment’s of coal transfer.1. Belt conveyors.2. Screw conveyors.3. Bucket elevators.4. Grab bucket elevators.5. Flight conveyors or scrapers.6. Skip hoist.

Shaikh Saif

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

BELT CONVEYORS (CONT.)Advantages1. Low cost & power consumption.2. Smooth & clean operation.3. Cheap maintenance.4. Controlled rate of coal transfer.

Shaikh Saif

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

SCREW CONVEYORS

Shaikh Saif

Advantages1. Cheap2. Requires small space, simple & tight.3. Dust tight.

Disadvantages1. High power consumption per ton of coal transfer2. Wear and tear of screw is high. Shorter life

BUCKET ELEVATOR Coal is lifted vertical or

near vertical direction. It carries the buckets

fixed to a chain. Buckets 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.

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:1. Requires less power for operation and

minimum maintenance.2. Used when other arrangements are not

possible.3. Lesser operating cost.

Disadvantages:4. Initial cost is high.

Shaikh Saif

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:1. Low capital cost.2. It can transfer both coal & ash.3. It can vary easily the rate of coal discharge.

o Disadvantages:1. High energy consumption & maintenance cost.2. High wear and tear due to dragging action.

Shaikh Saif

Shaikh Saif