Closing the loop – o n-farm fluidised bed combustion of p oultry l itter

Closing the loop – on-farm fluidised bed combustion

of poultry litter Deirdre Lynch

CarboleaUniversity of Limerick

Irelanddeirdre.lynch@ul.ie

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Huge energy requirements

Irish Average: 0.71 kWh per bird Recommended: 0.33 kWhEnergy Use in Agriculture: SEAI report 2011

8,000 litres LPG per batch€20,160 per year on heating alone.

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Cyclical supply of litter

1,285 million broiler chickens in EU / year

109 million tonnes of litter in EU / year

Source: FAOSTAT

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Energy

Waste

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Overview

Poultry litterPoultry litter

Fluidised bed

combustor

Emissions

Ash

Energy

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Characterisation of Poultry Litter

Proximate Analysis ar*

Result STDEV +/-

Moisture % BS EN 14774-3:2009

41.82 (18.68 – 51.8) 8.88

Ash %BS EN 14775:2009

9.13 (5.95 – 15.15) 1.98

Volatiles %BS EN 15148:2009

41.9 (35.01 – 56.83) 5.98

Fixed Carbon %by difference

7.81(5.03 – 11.72) 1.61

HHV MJ/kg BS EN 14918:2009

10.55 (8.75 – 14.27) 1.37

*ar = as received

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Characterisation of Poultry LitterUltimate Analysis db*

Result STDEV +/-

Carbon % BS EN 15104:2011

45.17 (42.02 – 48.61) 1.55

Hydrogen % BS EN 15104:2011

5.85 (4.97 – 6.55) 0.49

Nitrogen % BS EN 15104:2011

5.16 (3.83 – 6.40) 0.57

Sulphur % BS EN 15289:2011

0.45(0.29 – 0.6) 0.09

Chlorine % BS EN 15289:2011

0.35 (0.23 – 0.52)  0.23

Oxygen % By difference

27.25 (25.08 – 31.09) 1.41

Ash % BS EN 14775:2009

15.49 (10.61 – 19.58) 1.59

*db = dry basis

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Selection of FBC

– Suitable for poor quality fuels

– Good combustion efficiency

– Waste treated on-site

– Simple technology

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FBC Research Facility

Buffer Tank Hopper

HE 1

HE 2

Baghouse Filter

FBC

Secondary Air

Primary Air

Sand and Ash

Auxillary Diesel Burner

Cyclone

Evaporative Condenser

Ash Collection Points

Cleaned exhaust gas to atmosphere

ID Fan

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FBC Research Facility

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Emissions Monitoring

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Emissions mg Nm¯³ Result STDEV +/- WIDa

PM BS EN 13284-1 0.97 0.81 10HCl BS EN 1911 0.07 0.0094 10NOx BS EN 14792 359 9.0 200SO₂ BS EN 14791 < 0.03 0.0048 50CO BS EN 13526 30.6 2.8 50TOC BS EN 13526 2.2 0.22 10HF BS ISO 15713 <0.03 0.0038 1Cd + Tl BS EN 14385 0.001 0.0001 0.05Hg BS EN 13211 0.0004 0.00005 0.05Heavy metals BS EN 14385

0.041 0.0082 0.5aWaste incineration directive, Annex VReference Conditions: 273K, 101.3kPa, dry gas, 11% oxygen

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Combustion Ash Formation

• Evaporation of moisture

• De-volatilisation (decomposition)

• Char burnout & fragmentation

alkali metals SO₂/SO₃ chlorides

condensation

fine ash < 2 μmcoarse ash

> 2 μm

Poultry Litter Ash

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Fuel K2O CaO P2O5 MgO SO3 Na2OSiO

2Fe2O3 Al2O3

Poultry Litter 28.0 21.0 19.0 11.0 8.1 3.9 2.8 1.2 0.6

Miscanthus 5.2 12.7 6.5 10.8 n/a 1.3 53.3

1.2 2.4

Pine chips 4.5 7.9 1.6 2.4 1.2 1.2 68.2

5.4 7.0

Peat 1.1 9.8 3.5 2.1 11.9 0.1 36.9

13.6 19.8

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SiO2 Al2O3 Fe2O3

CaO MgO P2O5 K2O SO3 Na2O

GA 2.8 0.6 1.2 21.0 11.0 19.0 28.0 8.1 3.9

Bed 52.6 0.5 1.0 9.3 3.0 8.2 16.3 6.4 1.8

HE 1 6.4 0.95 1.0 25.6 8.6 27.5 21.15 5.1 2.6

HE 2 3.5 0.9 1.3 26.0 11.0 22.0 23.0 6.5 3.1

CYC 5.4 1.0 1.2 24.7 10.0 27.9 22.8 5.45 2.9

BH 1.5 0.2 0.3 7.3 2.7 7.75 69.8 6.9 1.2

GA – generated ash at 550°C, CYC – cyclone ash, BH – baghouse ash

Poultry Litter Ash

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Disadvantages of FBC• Ash – high K, Cl and S

– Bed agglomeration

50 mm

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Disadvantages of FBC• Ash – high K, Cl and S

– Bed agglomeration

0%

20%

40%

60%

80%

100%

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Position on line scan (mm)

Si

0.6 mm

0.1 mm

(b)

(a)

Inner Neck Outer

K Ca

P

Mg

S S

S Ca

Na

Fe

K

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Disadvantages of FBC• Ash – high K, Cl and S

– Bed agglomeration

0%

20%

40%

60%

80%

100%

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Position on line scan (mm)

Si

0.6 mm

0.1 mm

(b)

(a)

Inner Neck Outer

K Ca

P

Mg

S S

S Ca

Na

Fe

K

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Disadvantages of FBC• Ash – high K, Cl and S

– Bed agglomeration– Deposit formation

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Disadvantages of FBC• Ash – high K, Cl and S

– Bed agglomeration– Deposit formation

• Solution– Regular maintenance – Soot blowing– Refreshing the bed

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Conclusions• Fluidised bed combustion of poultry

litter 90 % reduction in waste

Low gaseous emissions

Potential fertiliser substitute

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Conclusions• Fluidised bed combustion of poultry

litter

Sustainable, closed loop system

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Thank you!deirdre.lynch@ul.iewww.carbolea.ul.ie

University of Limerick

Supervisors:Dr. J. J. Leahy

Dr. Witold Kwapinski