UTILIZATION OF RICE HUSKS
IN THE PRODUCTION OF
RENEWABLE ENERGY
by
Alexis T. Belonio, MS, PAE, ASEAN Engineer
Af filiate Professor
College of Engineering
Central Luzon State Univer sity
Science City of Munoz, Nueva Ecija
Lecture material during the Machinery Enterprise Training – Part 1:
PHILSCAT Rice Production and Postharvest Technologies for the Integrated
Rice Production and Processing Center (IRPPC) held at PHILSCAT Training
Room on December 3, 2014.
OBJECTIVES OF THE PRESENTATION
 To acquire knowledge on the properties of rice husks and its
importance as an energy source;
 To familiarize with the dif ferent methods of converting rice
husks into source of energy and power;
 To acquire an in-depth knowledge on the present technologies
available in converting rice husks into heat and power,
especially for agriculture and rural applications; and
 To be aware of the benefits of rice husk when used as source
of energy and power;
TOPICAL OUTLINE
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Introduction
What is Rice Husk?
Properties of Rice Husk
Energy Conversion Methods
 Direct Combustion
 Gasification
 Pyrolysis
 Rice Husk Energy Conversion Technologies
 Rice husk stove and furnaces
 Rice husk gasifier for heat and power
 Carbonizers for char production
 Social, Economic and Environmental Benefits
 Concluding Remarks
 References
INTRODUCTION
 Renewable energy is becoming popular as an alternative source
of energy worldwide as a result of increasing prices of crude oil
coupled with the need for clean environment.
 Biomass is one of the renewable energy sources that can have
significant impact especially in agriculture and in rural sectors.
 Among the different biomass which are readily available in the
rural and farming areas is rice husks, which constitute a large
parcel in rice producing regions.
 Annually, there are around 115 million metric tons of rice husk
available worldwide.
 In the Philippines, about 2 million metric tons are available per
year and is increasing with the introduction of high -yielding
varieties and of rice mechanization.
 With this scenario, harnessing biomass energy from rice residues
can be an alternative to produce cheaper supply of fuel for heat
and power especially in rice farming.
0.6
1.9
2.2
1.2 1.1
1.5
0.7 0.5 0.5
5.8
1 0.8
35.5
2.1
2.5
4.2
5.4
6.3
7.8
24.6
9.7
China
Thailand
USA
Cambodia
Rest of the World
India
Mayanmar
Korea
Nigeria
Indonesia
Philippines
Pakistan
Sri Lanka
Bangladesh
Japan
Egypt
Colombia
Vietnam
Brazil
Nepal
Laos
Average Annual Rice Husk Production of the World
Metric Tons
Philippines
1,932,846
CAR
39,064
Ilocos
168,125
Cagayan Valley
203,793
Central Luzon
341,191
Southern Tagalog
203,504
Bicol
149,098
Western Visayas
255,000
Central Visayas
38,004
Eastern Visayas
85,225
Western Mindanao
74,812
Northern Mindanao
78,019
Southern Mindanao
133,328
Central Mindanao
163,683
Annual Rice Husk Production of the Philippines (by Region)
RICE HUSK
 Rice husk is a by -product from milling
rice.
 It constitutes around 20% of paddy.
 At an average har vest of 4.5 tons per
hectare of paddy, 900 kilos of rice husk
is made available.
 At 6 tons per hectare, 1 .2 tons of rice
husk can be derived with the potential to
provide enough heat and power not only
for domestic rural application but also
for propelling rice machines.
 Studies have shown that 1 to 2 tons of
rice husks is enough to provide the
energy requirement for cooking by a
household for the whole year.
 Also, rice husk when used for heat and
power for agriculture can provide the
energy needed for water pumping,
dr ying, and rice milling. Estimated rice
husk consumption in per forming these
operations is 800 k g per hectare.
Rice Husk Disposal Practices (Philippines)
PROPERTIES OF RICE HUSK
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There are 100 kg of rice husks per 1 cubic meter of space.
Good rice husk contains 9 to 14% moisture.
One kilo of rice husk can provide an energy of 3000 kcal.
Molecular hydrogen/carbon ratio is around 1 .2 and 0.25 when
gasified.
Proper combustion of rice husk requires 4.7 kilos of air per kilo.
Gas can be generated when burning rice husk at a rate of 1 .2 kg
of air per kg of fuel.
When gasified, rice husk produces around 30 to 35% char. When
subjected to pyrolysis, it provides 40 to 45% char.
Rice husk char can hold water 5 times its weight.
Ash content is around 20% containing high amount of silica,
which is a good ingredient for the production of cement -fiber
board, refractory cement, and geo polymer blocks.
ρ = 100 kg/m3
HVF = 3000 kcal/kg
Mol H/C = 1.2
Stoich Air = 4.7 kg
air/ kg of fuel
MC = 9 to 14%
RICE HUSK
30 to 45 %
of RH
Mol H/C = 0.25
20% of RH
WHC = 5Wrh
CHAR
ASH
ENERGY CONVERSION METHODS
 Direct Combustion – Burning rice husks with excess air to
produce heat and water. The product of combustion is CO 2 .
 Gasification – Partial burning of rice husks with 30 to 40% air
to produce combustible gases rich in CO, H 2 and CH 4 .
 Pyrolysis – Burning of rice husks in an oxygen -starved
environment (10 to 30%) to produce primarily carbon and bio oil.
 Carbonization – when carbon is primarily produced.
 Bio-oil – when oil is primarily produced.
 Torrefaction – is the process of upgrading the fuel quality of
rice husk by removing moisture and portion of the volatile
matter.
Stove
Heat
Direct Combustion
Furnace
Gasification
Power
Heat
Gasifier
Rice Husk
Power
Pyrolysis
Stove
Carbonization
Heat
Furnace
Bio-Oil
Torrefaction
Gasifier
Power
Energy Conversion Methods of Rice Husk into Heat and Power
Direct
Combustion
Burning of rice husks
at an air-fuel ratio of
> 40 to 100
Gasification
Burning of rice husks
at an air-fuel ratio of
> 30 to 40
Pyrolysis
Burning of rice
husks at an air-fuel
ratio of > 0 to 30
RICE HUSK ENERGY CONVERSION
TECHNOLOGIES
 Stoves for Domestic
Cooking
 Multiple-Burner Stove for
Cottage and Institutional
Applications
 Gasifiers and Furnaces
for Drying, Oven, etc.
 Gasifiers for Water
Pumping
 Gasifiers for Electricity
Generation
Conical-Grate Rice Husk Stove with Steam Injection
Rice Husk Furnaces for Paddy Drying
Rice Husk Gas Stove for Domestic Cooking
Multiple-Burner Rice Husk Gasifier Stove for Food Processing
Rice Husk Gasifier for Paddy Drying
Rice Husk Gasifier for Paddy Drying
Rice Husk Gasifier for Twin-Bed Paddy Drying
Rice Husk Gasifier for Flash Drying of Paddy
Rice Husk Gasifier for Water Pumping
Rice Husk Gasifier for Water Pumping
Rice Husk Gasifier for Electricity Generation
Rice Husk Gasifier for Electricity Generation
Pyrolyzer for Production of Carbonized Rice Husk
SOCIAL, ECONOMIC, AND
ENVIRONMENTAL BENEFITS
 Cheaper source of fuel – cost of rice husks is very minimal
compares with crude oil and electricity.
 Utilization can be either for heat, mechanical power, and/or
electricity generation.
 Cleaner source of fuel for power farming.
 Added income to farmers.
 Creation of employment in the manufacture and distribution
of rice husk energy -generating devices in the locality.
 Additional revenue to the local government units in terms of
taxes.
 By -product can be used for:
 Carbon capture and storage activity which can be traded off
internationally.
 Soil restoration.
Rice Husk Char for Carbon Sequestration and Soil Restoration
CONCLUDING REMARKS
 Rice husk is good source of alternative energy for rural and
agricultural applications, especially in rice farming areas
where it is accessible.
 Rice husk can provide a low cost source of fuel for heat
application and, when gasified, can provide energy to provide
power to propel stationary agricultural machines and
generator to produce electricity.
 When converted via pyrolysis, rice husk can be a good source
of quality carbon and of bio -oil.
 Aside from supply of alternative energy, rice husk is also a
material for carbon sequestration and soil restoration. Its ash
can also be used for the production of local construction
materials such as cement-fiber board, geopolymer, etc.
REFERENCES
 B e l onio , A . T. , Ra m o s, J. A . Re g a la do , M . J. C. , a n d V. B . Oc o n . An Ove r view o f th e
D ow n dra f t Ri c e H us k s G a s i fier fo r Th e rm al a n d Powe r Appl i c a tio ns. Jo urn a l o f
Te c h n ology In n ovat ions i n Re n ewa ble E n e rgy. 2 01 3 , Vo l ume 2 , p24 6 - 2 58 .
 Be l o n i o , A. T. , O r g e , R . F. , Ta d o , J . C . M . R e g al ad o , M . J .C ., Ta yl a n , V. T.,
Pa r a s , F. O . , Am o n g o , R . M . C ., a n d Ta d e o , B. D .
R e n e wa b le En e r g y
Te c h n olo gi es f o r R i c e M e c h a niza tio n. Pa p e r p r e s en ted a t t h e AR F An n u a l
Ri c e Fo r u m 2 0 1 3 : M e c h an iza t i o n i n R i c e Fa r m i n g : St a tu s, Ch a l l e nge s a n d
O p p o rtu niti es h e l d a t BSW M Au d i t ori um , SR D C Bl d g . , Vi s a ya s Ave . c o r n er
El l i p t ica l R d . D i l i m a n , Q u e z o n C i t y o n N o v e m b er 2 2 , 2 0 1 3 .
 Be l o n i o , A. T. R i c e H u s k G a s i f ie r : Th e o r y a n d Ap p l i c ati on s. Pa p e r p r e s ented
a t t h e 2 5 t h N a t i o n al R i c e R &D C o n f e re nce h e l d a t t h e Ph i l i p pi ne R i c e
R e s e a rch I n s ti tute, Sc i e n ce C i t y o f M u n o z, N u e v a Ec i j a , Ph i l i p p in es o n
Se p t e mb er 4 - 6 , 2 0 1 2 . .
 Be l o n i o , A. T. R i c e H u s k G a s i f ie r: A R e n e wa b l e En e r g y Te c h n ol ogy f o r
Po ve r t y Al l e vi a t i o n. Pa p er r e s e nted a t t h e Fi r s t ( 1 s t ) Pr o f essi ona l Su m m i t
h e l d a t t h e M a n i l a H o t e l , M a n i l a o n O c t obe r 1 8 - 1 9, 2 0 1 2 .
 Org e , R. F. a n d J. E . O. Abo n . D e s ign Im prove ment o f t h e P h i lRic e Co n t inuo us Type Ri ce H ul l Ca rbo n izer fo r B i o c h ar P ro duc t i o n Towa rd Sus ta i n able
A g ri c ul t ure. OIDA In te rn a t ional Jo urn a l o f Sus t a i n able D eve lopment 0 5 : 0 8
( 2 01 2). pp. 8 3 - 9 6 . ( On t a rio In te rn a t ional D evelo pment A g e n c y. ISSN : 1 9 2 3 6 6 5 4 . h t t p: / / w w w. ssrn .c om/lin k/OIDA -Int l - Journ al -sust ain able - Dev. h t m l . )
THANK YOU VERY MUCH AND
GOD BLESS!!!
Recipient, Betterment for Mankind Award 2011, Pauchon Research Foundation (Morgan Hill, California, USA)
Laureate, Economic Business Development, The Tech Awards 2010 (San Jose, California, USA)
Associate Laureate, Rolex Awards for Enterprise 2008 (Geneva, Switzerland)
Awardee, Seven Inspiring Young Filipino Heroes 2011 (Yahoo Southeast Asia)
Awardee, The Outstanding Young Filipino 1997 in Agricultural Engineering (TOYM and Roxas Foundation)
Awardee, Outstanding Professional in Agricultural Engineering 1993 (Professional Regulation Commission)