DESIGN REQUIREMENTS FOR CHP

            The sizing and selection of the vital equipment i.e., crushers,screens,paddle feeders etc. covered under the system shall be based on the following characteristics of coal and operation conditions :

1. Two conveyors must be established (1W,1S) for smooth running of plant.
2. Simultaneous running of both conveyors at rated capacity is essential.
3. Round the clock operation of coal handling plant is essential.
4. Coal delivered to the power station shall be of size :300 mm & below (Occasionally 1-2% coal of 400 mm lumps may be allowed.
5. H.G.I of the   coal shall be between 45 to 65.
6.  Moisture content in coal will vary between 12% to 15% (For design purpose 20% is considered)
7. The coal  may have max of 20% of shale and sand stone.
8. For volumetric computation the bulk density of coal shall be taken as 800 Kg/M3
9. All hoppers and tunnels provided with 2 No.  sump pumps (1W+1S)
10. The coal unloading ysystem shall be capable of unloading the rake within time.
11. The wagon tipplers shall be "ROTA SIDE " type and the angle of tippling is 150deg by     giving 60 deg angle to the side of the wagon for emptying the coal contents into the hopper.
12. The tippler designed to allow passage of BROAD GAUGE (1676 mm) track over tippler table. 
13. The Wagon tippler hopper shall have capacity of 3 wagons i.e.180 tons .
14. The steel grating of mesh size 300mm X 300mm over wagon tippler hopper.
15. Belt Weigher shall be designed for a range of 20% to 120% of rated capacity.
16. RING GRANULATORS type crusher shall be provided for sizing the input coal to (-) 20mm (from 300mm). 

COAL CONVEYOR BELT-PROTECTION

           The coal conveyor belts in coal handling plant of thermal plants are protected by following ways 

1). PULL CHORD (Manually Reset type) : 

               This is a emergency stop switch  shall be located on both sides of belt conveyors at a a spacing of 20 Mtr. along the walkways for the entire length of conveyor for emergency stopping of conveyor.

2). SWAY SWITCH : 

              This switch is of self resetting type and it shall be provided at a spacing of 45 Mtr to limit belt sway to permissible extent.

3).ZERO SPEED SWITCH: 

             This switch is non-contact 9Proximity ) type electronic switch.

4). CHUTE BLOCKAGE SWITCH : 

             This switch is of proven type and it shall be provided at a suitable height on each leg of the conveyors discharge chute, Vibrating Screens by pass chutes ,Crusher feeding chutes ,Tripper discharge and feeding chutes nearest skirt boards.

               Chute blockage switch shall trip the feeding conveyor in case of chute blockage and protect the feeding conveyor equipment.   

 

DESIGN OF STOCKPILES

        The stockpiles of coal will have adequate storage power plants for few days and the coal consumption shall be based on the Heat rate and Average GCV of coal received.

PLANT LOCATION              COAL STOCK (Requirement)

PIT HEAD                                    15 Days

LOAD CENTERS                         30 Days

COASTAL                                    30 Days                           

BELNDING OF COAL

            In any coal fired power plants the blending of "Ingenious coal" and "Imported coal" can be done in following ways 

A).We can convey Indian coal through one stream and Imported coal through another  stream which will get mixed while falling into coal bunkers.

B). We can stock Indigenous and Imported coal layers in stockyard.Before feeding by using dozers we can blend  and feed to the bunkers.

C).We can use one mill is separately for Imported coal and then adjust the mill parameters to achieve the optimum heat load of the burners.