A CONTINUOUS-TYPE RICE HUSK GASIFIER FOR WATER PUMPING

by
Alexis Belonio, Emmanuel Sicat, Roel Pranilla, and Elmer Castillo
Glory to God!!
Rice husk gasifier can now
be used to provide power
for pumping water and for
generating electricity.
Farmers can now make
use of their gasoline
engine to run with rice
husks as fuel in lieu of
gasoline. This
development is another
accomplishment of the
Center for Rice Husk
Energy Technology Center
under the CLSU-CRHET
Rice Husk Project of the
College of Engineering,
Central Luzon State
University, Science City of
Munoz, Nueva Ecija.
The gasifier powergenerating unit converts
raw rice husks to gas by
partial burning producing
combustible gas rich in
carbon monoxide (CO),
hydrogen (H2
), and
methane (CH4
).  The gas
produced is allowed to
pass through the gas
cleaning device to remove
particulates and tars
before feeding it into the intake manifold of the engine. The engine subsequently drives the
pump that provides water for crop irrigation and the generator that produces electricity for the
The Rice Husk Gasifier-Pump System
The Irrigated Rice Farm
motors used in the
gasifier and in the
gas cleaning devices.
When the pump is
detached,
moreover, the
gasifier can provide
2 kW of electricity
which can be used
for lighting or for
running motoroperated
agricultural
machines.
As shown at the above photo, the gasifier is equipped with a 30-cm diameter by 120-cm high
moving-bed downdraft reactor where rice husks are gasified.  It is equipped with a 2½- in.
electric blower that pushes the gas through the bed of rice husks.  The wet scrubber, with a
spray tower made of a 4-in. diameter by 60-cm high GI pipe, is used to remove particulates and
tar by spraying the gas with water
a rate of 2.1m
3
/hr.  The tar is
allowed to condense inside a 40-cm diameter by 120- cm high
cylindrical tank serving as a
condenser for the liquid tar.  The
condenser has a 20-cm diameter
hole in the middle to allow natural
cooling of gas.  The gas is allowed
to pass through a packed-bed filter
having a diameter of 40 cm and a
height of 60 cm. The filter uses
rice husk with bed thickness of 45
cm. It has also a secondary filter
device having a diameter of 25 cm
and a height of 60 cm.  A 13-hp rated, single-cylinder, spark-ignition engine is used to convert
the gas into mechanical power. A 3-kW, 220-volt, single-phase, AC synchronous generator is
used to produce electricity needed for the gasifier.  A 3-in. diameter centrifugal pump
commonly used in shallow- tube well pumping is driven by the engine with the use of a beltand-pulley drive.
The gasifier can pump water at a rate of 511 to 621 liter per minute with a total head of 2.0 to
2.5 meters. While pumping, it also provides 1 kWe power for running the various parts of the
gasifier and the gas conditioning devices.  It consumes rice husk fuel at an average rate of 10.3
kg per hour and produces char at a rate of 2.75 kg per hour. The gasifier requires 13 to 15
The Rice Husk Char from the Gasifier
minutes start up time to produce the combustible gases needed by the engine. The gas
generated from the reactor has a temperature of 249° to 289°C  after passing through the filter,
moreover, the gas temperature has cooled down to 39° to 43°C.  The water in the scrubber
needs to be replaced once a week or when the tar at the scrubber is already thick.  The filter
material, which is rice husks, needs to be changed every day. Once dried, this filter material
can be used again as fuel.  The engine runs at a speed of 2197 to 2385 rpm while the pump runs
at 1440 to 1689 rpm. The generator is maintained at 220 volt in order to provide the required
electrical load for the gasifier and the gas conditioning devices.  The computed rice husk
gasification rate is 147.1 kg/hr-m
2
. The amount of rice husk needed to pump water is  0.30
kg/m
3
of water.
The advantage features of this gasifier system are: (1) It uses rice husks  commonly found in rice
farming areas as fuel which can augment fuel supply for pumping water; (2) The design is
simple which can be constructed using local materials and labor; (3) The by-product can be
used as a soil conditioner which can be immediately spread in the field to increase the water
holding capacity of the soil as well as to enhance crop growth; (4)Almost no smoke during
operation and produces low CO
2
and black carbon emission; (5) Farmers who used to operate
an engine can be easily trained to operate and maintain the gasifier.  Nevertheless, the gasifier
is fuel-specific in which rice husks is the only biomass that can be used as fuel.   Mixing other
biomass will affect the performance of the gasifier.
The investment cost for the gasifer reactor, gas conditioning system as well as the engine,
generator, and pump is around P150,000.00 (as of September 2012).  Providing a shed for the
gasifier will incur an additional cost of around P25,000.00.  At P2.00 per kg of rice husks and
P54 per liter of gasoline, using the gasifier would entail a saving of around 50 to 60% on fuel
cost. Payback period for the gasifier system is less than a year.  
For further information, please contact:
The Project Director (atbelonio@yahoo.com)
Center for Rice Husk Energy Technology
CLSU-CRHET Rice Husk Project
Room 201, PHILSCAT
College of Engineering, Central Luzon State University
Science City of Munoz, Nueva Ecija, Philippines
Acknowledgment:
CRHET acknowledges Pauchon Research Foundation of Morgan Hill California for the support in carrying out this
project to develop series of micro-gasifier power generating units to benefit the rural people, especially the
farmers. The Tech Awards 2010 and the Rolex Awards for Enterprise 2008 for the funding support in the early
development of rice husk gasifiers, particularly the moving-bed downdraft-type reactor.
Released: September 2012