WOOD CHARCOAL GASIFIER STOVE

by Alexis Belonio and Djoewito Atmowidjojo
Wood charcoal is basicallyproduced forexport and local
market in Indonesia.  However, these markets have
specific requirement as to the size of wood charcoal, which
is more than 3 cm. The undersize wood charcoal (1-3 cm
in size) at present is not easy to sell commodity.
In the province of South Sumatra, Indonesia, wood
charcoal is being produced inlarge scale. One factoryin
Bilitung Island in this province, theBilitung Charcoal
Factory,is  producing 120 tons of wood charcoal per
month. Ten to fifteen percent of this total production
consists of small or undersize wood charcoal. At present,
it has accumulated 20 tons of undersize wood charcoal and
the company is having a problemof its disposal. On the
other hand, this waste materialcan be a potential source of
fuel for the households in the area for their cooking as an
alternative for kerosene, LPG, and wood.
In order to make use ofthis waste  material, the PT.
Minang Jordanindo Approtech- Research and Development Division
has designed and developed a gasifier stove that utilizes this
undersized wood charcoal as fuel. The wood charcoal gas stove
(upper-right picture), is highlysuitable for domestic use. The design
of the stove issimpleusing locallyavailable materials and skills inthe
fabrication. Itis convenient to operate and requires less maintenance.
It can effectively convert solid fuel into burning combustible gases for
cooking and heating. It isan environment-friendly technology that
can address indoorair pollution problem, particularlyindomestic
household cooking. Carbonized coal, wood chunks, and other smallpiece agri-residues can also be used as fuelfor this wood charcoal gas stove.
Description of the Stove
WOODCHARCOALGASIFIERSTOVEPARTS
Cut-AwayView
Inner
Cylinder
RiceHusk Ash-CementInsulation
SlidingDoor
Fan
PotSupport Burner
AC-DC
Adaptor
Outer
Cylinder
Grate
HeatCover
The wood charcoal gasifier stove, as shown, is a
modified version of the top-lit updraft (TLUD) type
wood gas stove developed by various researchers
around the world. Itbasicallyconsists of the
following major components: (1) gasifier reactor
assembly, (2) fan assembly, and (3) burner assembly.
The reactor assemblyis where the fuel is gasified by
supplyinglimited amount of air during the combustion
of fuel. The inner cylinder is made ofstainlesssteel
sheet no. 304 having adiameter of 8 cm and a height of
20 cm. The outer cylinder, which encloses the reactor,
is made of 0.4 mm black iron sheet having a diameter
of 22 cm and a height of25 cm. Rice husk ash and
cement mixture is used toinsulate the reactor.  A
0.25-in. stainless steel perforated sheet is used to hold
the fuel. The stove is provided with a sliding-type
door for ease of removal ofashes after each operation.
The air needed to gasifythe fuel is supplied bya 6-cm
diameter, 12-volt electric blower. An AC-DC adaptor
is used to connect the blower to the AC outlet. The
gas produced fromthe reactor is released to a drum
type burner where it is ignited to produce heat for
cooking. Four pieces of  metal  sheet frame are
provided for the burner to hold the pot in place during
cooking.
Stove Performance
Performance testing of the stove showed that the reactor can
contain 288 to300 grams of undersizedwood charcoal per
load. Ignition of fuel can be easilyachieved within 3 to 7
minutes using a single piece of paper. It can boil a liter of
water within 6 to 15 minutes, dependingon the amount of
air supplied in the reactorduring operation. One load of
fuel can sustain 40 to  46 minutescontinues operation.
Adding fuel into the reactor can prolong the operation of the
stove on a continuous mode. The temperature of the flame,
measured at the top of the burner using a pyrometer, ranges
from 400 to 450 C. No emission of smoke and foul odor
was observed during  the tests. The computedfuel
consumption rate of the stove is 0.39 to 0.43 kg/hr while the
specific gasification rate ranges from  78 to 86 kg/hr-m
2
.
The amount of char produced after gasification is between 5
to 8%, the thermal efficiency ranges from18 to 22%, and
the power output was computed at 0.7 to0.9 kW. The stove
costs onlyRp150,000.00 ( 1 US$ = Rp9,200), which can be
recovered in 6 months .
Acknowledgment and Contact Info
The stove was developed with the assistance of the following: Franciscus TryaGarleman and Daniel
Belonio of PTMJ Approtech - Research and Development Division; and Emmanuel Ginting of
MetallurgyResearch Centre, Indonesian Institute of Science. Mass production of the stove in Indonesia
will be done in October of this year. Interested individuals or organizations toadopt this technology may
contact The President Director, PT Minang Jordanindo Approtech, ADHI GRAHA Bldg., 15
th
Floor
Suite 1502A, Jl Gatot Subroto Kav. 56,Jakarta Selatan 12950, Indonesia. Telephone: 62-21-5262545,
Fax: 62-62-215262416; and Email: djoewito@yahoo.co.id.