Calculation of coal handling plant and bunker capacity

Coal handling plant (CHP) consists of ;

• Coal unloader from vehicles

• Coal storage yards

• Coal vibrofeeders

• Coal vibroscreen

• Magnetic seprators

• Coal crusher

• Coal weigher

• Series of Conveyors

• Water sprinkling system

• Coal shuttle conveyor

• Coal storage bunkers

Inorder to calculate the coal handling and coal storage bunkercapacity, first we need to know the coal requireent per day for a plant, coal handling maintenance stratergy

We shall calculate the coal handling & bunker capacity by taking an example of 25 MW thermal power plant consuming coal of GCV 4900 kcal/kg & having heat rate 3200 kcal/kwh running at 100% PLF.

Plant running load = 50 MW X 100/100 = 25 MW

We know that coal consumed = Heat rate X Power generation / (Coal GCV)

Coal consumed =3200 X 25 / 4900 = 16.32 MT/hour

Coal consumed in a day = 16.32 X 24 =391.68 MT take round figure 392 MT/day

A-Coal handling capacity calculation

Consderations:

• Coal handling plat is operated 14 hours in a day

          Note: Some designer consider operating hour of the plant is 10-12hours

• 10 hours used for cleaning and preventive maintenance

CHP capacity =392/14 =28 Tonnes / hour

Take 50% extra margin on capacity

CHP capacity = 28 X 150% = 42 Tonnes/hour

Power plant Maintenance Calculations

B-Coal yard design

For 25 MW power plants coal can be supplied through truckes & lories .It is sufficient to keeping the stock of 7-8 days coal in coalshed.

Coal shed capacity = Lenght 50 meter X Width 30 meter X Avg Height of coalheap 4 meters X coal density 800 kg/m3 = 4800 MT

Which han hold the coal for 12 days of full load operation days

If the plant is of bigger size, then the coal is supplied through railway & Wagons & stored at yard..

Yard capacity =Length X Width X avg.Height of 6 meter X Coal densitykg/3

Coal from Shed & yard is then shifted & dozed to vibrofeeder hopper through chain & tractor dozers

C-Selection of bunker capacity

Buker capacity is generally designed for 12-14 hours of full load operation

Let us calculate with 12 hours of operation hours

Coal consumption in 12 hours = 392 X 12 /24 =196 MT

Volume of bunker = 196 X 1000/800 = 245 M3

Take 10% of extra margin on bunker as some of coal stucked on bunker wall surface cannot be used for Boiler. Which is unaccountable

So total water volume of Bunker = 245 X 110% = 269.5 take round figure =270 M3