A 3-KW RICE-HUSK MICRO GASIFIER POWER-GENERATING DEVICE DEVELOPED FOR INDIVIDUAL FARMER’S USE

by
Alexis T. Belonio, Emmanuel V. Sicat, Marlon T. Delos Santos, and Elmer D. Castillo
Good news and
Glory to God!!
Amid problem on
high fuel cost, a
practical solution is
at hand. Farmers
now have an
alternative in
generating
electricity for their
home use with the
latest development
on rice husk
gasification
technology to run
small-gasoline
engine that can
drive a 3-kW
generator. This
rice-husk micro
gasifier power-generating device is one of the
developmental activities of the Center for Rice Husk
Energy Technology –Central Luzon State University
(CRHET-CLSU) Rice Husk Project purposely to come
up with a simple technology that utilizes rice husks,
which are the by-product from milling rice and can
augment farmers’ income thus improving their living
condition. With this technology, farmers can now
utilize their rice husks to provide power for their
home energy need such as lighting, radio and TV,
charging cell phones, cooking with electric stove,
and even to supply electricity for their domestic
water pumping need as well as for irrigating their
crops.  With the introduction of this latest
development on rice husk gasification technology,
agro-wastes produced in the farms can now be
turned to a useful energy source in meeting  the
need of farmers for electricity while, at the same
time, making the environment free from pollution.
This 3-kWe rice-husk micro gasifier power-generating device is a
small version of the continuous-type rice husk gasifier, with gas
conditioning units, producing clean gas that is used as fuel for
conventional spark-ignition gasoline engines. As shown in the
drawing above, this device consists of the following major
components: (1)  Gasifier reactor used to convert rice husks, by
burning them with limited amount of air, into combustible gases
rich in carbon monoxide (CO), hydrogen (H2), and methane (CH4);
(2) Wet scrubber used to remove particulates and tars by spraying
the gas generated with water; (3) Tar condenser used to turn
moisture from gas into liquid form; (4) Packed-bed and cloth filters
used to mechanically screen the gas in order to further separate
tar from water; and (5) Engine used to produce mechanical power
to drive a generator. All these components are joined together in
series to completely clean the gas as well as to reduce its
temperature.
The gasifier reactor has a 20-cm
diameter equipped with a 2-in.
electric blower to push the gas into
the bed of rice husks. The wet
scrubber has a spray tower made of
a 4-in. diameter by 60-cm high GI
pipe, which sprays water into the gas
at a rate of 2.1m
3
/hr. The tar
condenser has a 40-cm diameter and
a 120-cm height. It has also a 20-cm
diameter hole at the middle to
provide natural cooling of gas at the
condenser.  Moreover, the packedbed filter has a 40-cm diameter and
a 60-cm height.  It uses ½-in.
diameter by 45-cm thick bed
crushed-stones as filter.  It has also a
filter bag made of a 25 cm  x 60 cm
long cloth to further screen the gas
before injecting it into the intake
manifold of the engine.   A 13-hp,
single-cylinder, spark-ignition Kenbo
Engine is used to convert the gas into mechanical power. A 3-kW, 220-volt, single-phase, asynchronuous
generator is used to produce electricity.
The gasifier consumes rice husks at a rate of 6-7 kg/hr producing a 2.9 kW electricity, with 0.9kW
parasitic load. The gas leaving the reactor has an average temperature of 180–260C and subsequently
drops to 30-35C after passing through the wet scrubber, tar condenser, and filters.  The engine
requires 12-15 min to start up with gasoline.  Once the engine has started, it is then run with the gas
generated from the system. Towards the end of the operation, however, the engine is run again with
gasoline for 10 minutes before shut off to clean the engine combustion chamber from tar.  No
modification is done on the engine, except for the provision of an intake port that by-pass the
carburetor. Operation of the plant is simple and can be easily understood by farmers who have the
experience in operating engines.
This power-generating device,
including the gasifier, the gas
conditioning units, the engine and
the generator, requires an initial
investment of around P55,000.00. If
farmers will save his rice husks and
use it as fuel, he can generate power
for his house and farm uses at less
than P3.36 per kw-hr. Comparing
this with the prevailing cost of
electricity of P10.50 per kw-hr, a
daily saving of P85.79 to 209.73 can
be derived.  The investment for the
entire system can be recovered
within 0.72 to 1.76 years depending on the utilization.
Aside from the saving that can be derived by farmers, this technology can benefit the farmers
themselves, the community and the country, in general, in terms of the use of a clean energy,
generation of employment for local people, availability of electricity for the farms especially in remote
areas which can impel micro business enterprises, increase in revenue for the locality, and improve
quality of life of the people in rural areas.
For more detailed information, kindly contact:
Engr. Alexis T. Belonio
Project Director, CRHET-CLSU Rice Husk Project
College of Engineering, Central Luzon State University
Science City of Munoz, Nueva Ecija, Philippines
Email: atbelonio@yahoo.com
We wish to thank Pauchon Foundation of Morgan Hills, California, USA; and the 6m’s Ag Biosystem
Engineering Enterprise and Consultancy Corporation, Philippines for providing the funds in developing
this power-generating device. The Super Trade Enterprise,Philippines for the allowing us to use their 13
hp KENBO Engine for the testing and evaluation of the gasfier as well as the Agricultural Engineering
Students of CLSU (Genesis Lazo, Roel Pranilla, and Rafael Domingo) who helped in testing and evaluating
the device.
May this technology help our farmers especially those who don’t have access to the grid!
Released: March 2012