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RICE HUSK UTILIZATION IN THE MEKONG, RIVER DELTA, VIETNAM

PHAM THI MAI THAO

Angiang University

The 2nd International Conference on Sustainability Science in Asia

March 2 - 4, 2011, Hanoi, Vietnam

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Contents

1 – Introduction

2 – Objectives

3 – Scenario Development

4 – Life Cycle GHG assessments

5 – Conclusions

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Huge amount of rice husks is generated and most of them are illegally

dumped into canals and rivers

Currently, open burning of rice husks has increased causing severe fire

accidents and respiratory diseases

Therefore, if they are utilized as energy source, not only GHG

mitigation but also improvement of local environment can be

achieved

1 Introduction

Problems from rice husk generation

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2 Objectives

Evaluate LC-GHG emissions of the 18 developed scenarios

The obtained results can answer the following questions:

How much GHG emissions can be mitigated by using rice husk?

Which technology shows higher mitigation potential?

Which stage of the process contributes to the total GHG

emissions?

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Area: 3.4 thousand km2

Adm. division: 1 city, 1 town, and 9 districts

Population: 2.2 million people

Density: 625 persons per km2

Rural population: 71.75 %

Total agricultural area: 75% of total land area

Rice area: 520 thousand ha (three seasons)

Rice production: 3.10 million t/y

Rice husk generation: 620 thousand t/ySource: Angiang, 2007

VIETNAM

VIETNAM

VIETNAMVIETNAM

3 Scenario development

Study area - Angiang province

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18 scenarios were developed based on (1) current demand and supply of rice husks and (2) rice husk and rice husk briquette use technologies

S: scenario; B - briquette; a - medium scale (5 MW); b - large scale (30 MW) of power plants

3 Scenario settings

Coal, LPG, fuel wood

National electricity

Diesel oilFue

l rep

lace

men

t

Cooking Brick burningCombustion

(power)Gasification

(power)Pyrolysis

Rice huskBriquette

S1, S1B1, S1B2, S1B3S2a,b, S4a,b,

S2Ba,b, S4Ba,bS3a,b, S5a,b, S6, S7

Steam Gases

Heat Electricity Bio-oil

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For the rice husk scenarios

For the briquette scenarios

Fuel allocations

Baseline Scenario 1

Scenario 2 (a, b)

Scenario 3 (a, b)

Scenario 4 (a, b)

Scenario 5 (a, b)

Scenario 6

Scenario 7

0

20

40

60

80

100

Perc

enta

ge, %

9

26

65

74

26

9

26

65

9

26

65

100 100

9

26

65

100

CookingBrick makingOpen burningCombustionGasificationPyrolysis

Baseline Scenario 1B1

Scenario 1B2

Scenario 1B3

Scenario 2B (a, b)

Scenario 3

Scenario 4B (a, b)

Scenario 5, 6, 7

0

20

40

60

80

100

Perc

enta

ge, %

9

26

65

80

20

9

26

65

74

26

9

26

65

100

CookingBrick makingCombustionOpen burninga - 5 MW; b – 30 MW

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4 Life Cycle - GHG emissions

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(1) COOKING

Cook stove

Combustion

Rice husk

Heat energy

Non-CO2 GHGs

(a)

(d)

Legend(a) - IPCC default value

(b) - Literature review(d) - Calculated taking into account of efficiencies

(b)

Stove production & disposal

Out of boundary

14 Boundary settings and data preparation

Emission replacement: Coal, LPG, fuel-wood combustion

Emission source: Rice husk/briquette combustion

Transportation

Walk, bicycle or wood boat

Out of boundary

Replacement of Coal, LPG, Fuel wood

A B

Total emission reduction, (A-B)

GHG

(d)

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CombustionPower Plant

Rice husk Transportation

Combustion RH(d)

Legend(a) - IPCC default value(b) - Literature review(c) - Interview data(d) - Calculated data

Boiler

Steam

Turbine/Engine

Emission replacement: National electricity

(a) (b)

Non- CO2 GHGs

Residual Oil

(b)

GHGs(a) (b)

Diesel

(c)

GHGs

(a)(b)

Diesel production

GHGs

Residual oil production

(b)(b)

Construction & Disposal

GHGsOut of boundary

(b)

Plant operation

10%(b) Replacement of National Electricity

GHGs

Electricity(d)

(d)Total

emission reduction

= Emissions - Emissions

Emission source: Transportation, rice husk combustion in power plant, start-up

(2) COMBUSTION POWER PLANT

Construction and disposal emissions are included and discussed in total emission mitigation potential section

14 Boundary settings and data preparation

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(3) GASIFICATION POWER PLANT

Gasification power plant

Rice husk Transportation

Combustion RH

Legend(a) - IPCC default value(b) - Literature review(c) - Interview data(d) - Calculated data

Gasifer

Gases

Turbine/Engine

Air

14 Boundary settings and data preparation

(b)

Non- CO2

GHGs

Emission replacement: National electricity

(c)

Diesel

(a)

GHGs

(b)

Diesel production

GHGs

(b)

Construction & Disposal

GHGs

Out of boundary(b)

Emission source: Transportation, rice husk gas combustion in power plant

Total emission reduction

= Emissions - Emissions

(d)

(b)

(d)

Replacement of National Electricity

GHGs

Plant operation

Electricity

10%

Construction and disposal emissions are included and discussed in total emission mitigation potential section

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(4) PYROLYSIS PLANT

(d)

Pyrolysis Plant

Rice husk Transportation

Combustion RH

Legend(a) - IPCC default value(b) - Literature review(c) - Interview data(d) - Calculated data

Reactor

Crude bio-oil

Catalytic reactor

14 Boundary settings and data preparation

Emission replacement: Diesel oil

Diesel

(a)

GHGs

(b)

(b)Catalyst

(b)

Nitrogen gas

(b)Electricity Plant

operation

(d)

(b)

(b)

(b)

Diesel production

Electricity generation

Catalyst production

Nitrogen production

GHGs

(b)Construction & Disposal

GHGs

Out of boundary

(d)

(d)

Replacement

of Diesel

GHGs

Upgraded Bio-oil

Total emission reduction = Emissions - Emissions

Emission source: Transportation, Nitrogen gas and catalyst production, electricity consumption

Construction and disposal emissions are included and discussed in total emission mitigation potential section

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Bri

qu

ette

p

rod

uct

ion

Nat

ion

al g

rid

ele

ctri

city

p

rod

uct

ion

14 Boundary settings and data preparation

(c)

ElectricityElectricity generation

GHGs

(d)

Out of boundaryMachine production

& disposal

PO

WE

R P

LA

NTAnthra-

cite coal

(b)

Legend(a) - IPCC default value

(b) - Literature review

Diesel

Natural gas

(b)

(b)

(b)

Electricity

Hydro power

37%

8.1%

19.6%

35.3%

(b)

(a)GHGs

(b)

Anthracite coal production

(b)

Diesel oil production

(b)

Natural gas production

(b)

GHGs

Replacement of RH, Coal, LPG, Fuel wood

GHGs

(d)

Rice husk Briquetting machine

Briquette

Legend(c) - Interview data(d) - Calculated data

(d)

Vietnamese elect. Emissions (*)

CO2eq : 0.459 kg/kWh

(*) Calculated based on energy consumption and total generated electricity (2007)

To product 1kg briquette need 1.05 kg rice husk 0.13 kWh electricity

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24 GHG emissions per 1 kWh electricity

Rice husk combustion power plants: combustion Rice husk gasification power plants: fuel transportation Briquette combustion power plants: briquette production

0.0050.006

0.066

0.032

0.077

0.050

0.000

0.020

0.040

0.060

0.080

0.100

S2a S2Ba S2b S2Bb S3a S3b

Combustion Start-up Transportation Briquette production

GH

Gs

em

iss

ion

, k

gC

O2

eq/k

Wh

0.400

0.500 5 MW 5 MW30 MW 30 MW0.459

Combustion Gasification

National electricity

Main stage contributes to total GHG emissions per 1 kWh electricity

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34 GHG emission change from baseline

The maximum mitigation potential from S2Bb (0.22 million t/y) accounts for 0.23% of the GHG emissions

in Vietnam (98.6 million t/y) [1]

Total net generated electricity Maximum: 721 GWh/y from S4Bb; Minimum: 198 GWh/y from S2a

It can supply from 17 - 60% of total electricity consumption in Angiang province (1,2000 GWh/y) [2]

[1] (UNDP, 2008); [2] (Angiang Department of Electricity, 2009)

-4.0

-3.0

-2.0

-1.0

0.0

1.0

2.0

3.0

Cooking Brick making Briquette productionPower generation Bio-oil generation Open burningElectricity replacement Diesel oil replacement Cooking fuel replacementTotal GHG change

S1

S1B

1

S1B

2

S1B

3

S2a

S4a

S4B

aS

2Ba

S2b

S4b

S2B

bS

4Bb

S3a

S5a

S3b

S5b

S6

S7

30 MW5 MW 5 MW 30 MW

Ba

se

lin

e

Inc

rea

se

, 10

5 t/y

De

cre

as

e, 1

05 t

/yCooking Combustion Gasification Pyrolysis

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All scenarios give GHG emission mitigation potentials, the innovative technologies

show higher mitigation potentials than the conventional uses

5 Conclusions

Among the cooking scenarios: GHG mitigation potentials of rice husk and

briquette are not significantly large

Among power generation scenarios

S2Bb using briquettes in large-scale combustion power plants (30 MW)

keeping current rice husk demand shows the highest GHG emission

mitigation potential

S3b using excess rice husk for small-scale gasification also shows larger

mitigation potential

Among pyrolysis scenarios: S6 using excess rice husk shows larger GHG

emission reduction than the scenario using all rice husk generated (S7)

The effective options for GHG mitigations are to use excess rice husk for large-scale

power generation through combustion or gasification keeping current rice husk

demand

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On going to construct rice husk power plants financed by

Swedish government

Reuse catfish oil for bio-oil generation

Biogas generation from animal residue and wastewater

treatment’s sludge

6 Projects for developingbioenergy production and utilization in Angiang

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Thank you very much for your attention!