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Bua Sommai Biomass Co., Ltd., Thailand

9.0 MWe Biomass Based Power Plant Page 1 of 4

ASH HANDLING SYSTEM DESIGN FOR THE POWER PLANT

1.0 BOILER DATA:Description Parameters

Type

Bi-drum, balanced draft, natural

circulation, semi-outdoor type,

travelling grate boiler.

Boiler Capacity (MCR) 50 TPH

Steam pressure at Main Steam

Stop Valve Outlet66 kg/cm2 (g)

Steam temperature at Main

Steam Stop Valve Outlet485 + / - 5 Deg C

Feed water temp at Economiser

Inlet130 Deg C

Feed water temp at Deaerator

Outlet130 Deg C

Design Fuel 100% Rice Husk

Boiler efficiency (GCV basis) 80 %

Heating surface area 2538 Sq. m

Travelling grate surface area 29.77 Sq. m

2.0 FUEL DATA:Fuel : Rice Husk

Gross Calorific Value : 3400 kcal/kg

Bulk density : 120 kg/m3

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Fuel Ultimate Analysis, % by weight

Sl. No ConstituentWet basis

(% by weight)

Dry basis

(% by weight)

1 Carbon 36.40 39.20

2 Hydrogen 3.58 3.86

3 Oxygen 37.99 40.92

4 Sulphur 0.04 0.043

5 Nitrogen 0.55 0.59

6 Chlorine 0.08 0.09

7 Moisture 7.15 0.00

8 Ash 14.21 15.30

Fuel Consumption during Normal operation

(9.0 MW 39 tph steam output from Boiler) : 9797 kg/hr

Fuel Consumption during MCR operation (50 tph) : 12560 kg/hr

3.0 FLUE GAS DATA FROM COMBUSTION:3.1 Flue Gas Analysis:

S.No. Constituent % By Vol.

1 CO2 14.680

2 H2O 12.743

3 O2 4.636

4 N2 67.925

5 SO2 0.017

3.2 Volume of flue gas at MCR condition:Wet basis : 62714 Nm3/hr

Dry basis : 62029 Nm3/hr

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3.3 SOx generation at MCR condition (Dry basis)

Basis : 7% O2 dry basis

Excess Air : 50 %

Flue gas volume = 68099 Nm3/hr

Suphur content in fuel = 0.043 %

Fuel consumption = 12560 kg/hr

SO2 generation = 10.80 kg/hr

SOxquantity at MCR condition = 158.59 mg/Nm3

= 55.45 ppm

3.4 NOx generation at MCR condition (Dry basis):NOx generation :

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Density of flue gas = 0.864 kg/m3

Flue Gas volume from boiler to ESP = 95088 m3/hr

Density of flue gas at NTP condition = 1.31 kg/Nm3

Gas volume from boiler to ESP = 62714 Nm3/hr

Ash content in fuel = 14.21 %

Fuel consumption = 12560 kg/hr

Total Ash generation = 1785 kg/hr

Bottom Ash quantity (40%) = 714 kg/hr

Fly Ash quantity (60%) = 1071 kg/hr

Inlet dust loading to ESP = 17.00 gm/Nm3

Outlet dust concentration = 100 mg/Nm3

Total ash collected in ESP = 1065 kg/hr

ESP Collection efficiency = 99.41 %

6.0 ASH COLLECTION DATA:Ash content in fuel = 14.21 %

Fuel consumption = 12560 kg/hrTotal Ash generation = 1785 kg/hr

Ash collection distribution :

Furnace Front Ash (25%) = 446 kg/hr

Bank ash hopper (5%) = 89 kg/hr

Economiser & APH ash hopper (10%) = 179 kg/hr

ESP Ash hoppers (60%) = 1071 kg/hr