[Gasification] Some Text on the Chinese Gasifier

Wed Nov 15 18:49:25 CST 2006

Dear Tom

This description is not at all close to the gasifier at our website
http://www.wattpower.com/wpindex6.html

Our unit is steel external construction with a refractory lining, while the 
unit described is said to be "cast iron in contact with the fire." Ours is 
clearly a gasifier, in that it produces a fuel gas, and there is no 
provision for secondary air, or combustion after gasification, except by 
piping the gas to a clearly separated 2 burner wood gas stove.

The device described in this text seems to be an updraft stove system. It is 
difficult to tell if it is a TLUD, or a BLUD, but it is definitely an 
"updraft smoke maker." They clearly refer to the addition of secondary 
air... " When the smoke reaches up to the opening on top of combustion
chamber, air comes in again.".... I would suggest that it is a real stretch 
to call this a "gasifier"... It is more like a "TL / BL Up Draft Smoke 
Burning Stove."

Note they also state "8. It is small, light, and portable."... The Wattpower 
Gasifier weighs about 180 kG, and is not at all "small and light"

The device described here could make a good stove system, in that is should 
be able to handle relatively wet fuel, with the updraft gases drying the 
fuel of its excess moisture. The gases would be expected to be very tarry, 
but then, with immediate combustion, this would not be much of a concern. It 
does seem to be a simple and durable system, and might turn out to be 
surprisingly similar in concept to the stove system presented by Dr. Reddy.

Best wishes,

Kevin

----- Original Message ----- 
From: "Tom Miles" <tmiles at trmiles.com>
To: "'Peter Singfield'" <snkm at btl.net>; <gasification at listserv.repp.org>
Sent: Wednesday, November 15, 2006 4:00 PM
Subject: Re: [Gasification] Some Text on the Chinese Gasifier

Peter,

Is this text for the same gasifier? Do you have a web source for this text?

Did we figure out how this gasifier works? Since it is "open" at the top
with a limited air entry it looks to me like it would run like a 5" diameter
stratified downdraft gasifier. As you light it from the top and pull air
through it it would just pull a column of air through the center. Since it's
fuel rich it would gasify rather than combust. As fuel disappears the cone
would allow new fuel to drop and fill the center column.

http://gasifiers.bioenergylists.org/singfieldgas

I would think that the gas quality would vary quite a bit while it is
"refueling." A combustor can handle that. Can an engine?

Maybe Kevin can enlighten us, or Peter if you've run the gasifier.

Tom

-----Original Message-----
From: gasification-bounces at listserv.repp.org
[mailto:gasification-bounces at listserv.repp.org] On Behalf Of Peter Singfield
Sent: Monday, November 13, 2006 7:05 PM
To: gasification at listserv.repp.org
Subject: [Gasification] Some Text on the Chinese Gasifier

Some extra info for the curious.

Biomass Gasifier Stove for Rural Households Lou, Zhongxian

Luoyang Institute of Mechanical Engineering, Henan, China

Cast iron biomass gasifier stove is a kind of environmental friendly, energy
saving and high efficient stove. The fuel is gas-combusted it. A few minutes
after ignition, flame bursts out of the combustion chamber from the opening
on top. There is obviously a space of biomass gas between the fire and
carbonized wood. This kind of stove increases temperature quickly, for
instance, to burn corn hulls in a combustion chamber of 0.013m³, the
temperature increases 6.1°C/min; the evaporation rate of water is
0.07kg/min; the stove also has excellent adiabatic property that the
temperature recover rate is as high as 0.9°C/min.

Biomass is referred as crop residues, wood twigs, weeds, animal dungs and
all the other organic materials. The broad definition of biomass should
include household waste, industrial and agricultural waste.

The mechanism of cast iron biomass gasifier stove is: in the thermo-chemical
reaction of biomass, under the anaerobic condition , biomass is burnt, mixed
with air once, then thermally decomposed to a mixture of flammable gases,
including CO, CH4, H2, which is called "smoke"
in general. When the smoke reaches up to the opening on top of combustion
chamber, air comes in again. As the temperature around the opening reaches
the flash point of smoke rapidly (about 650°C), it is burning at its gas
state of which the energy density is high. Therefore, the fuel efficiency of
this kind of stove is high, as well as the thermal efficiency which can be
greater than 49%. When the chamber is warmed up, the speed of consuming gas
and the speed of generating flammable gas from thermal decomposition can
reach a dynamic balance easily; that is, the stove can keep burning at a
constant rate.

The features of cast iron biomass gasifier stoves include:

1. It can be applied to a wide broad of inexpensive fuels, such as wood
twigs, leaves, crop residues, weeds and animal droppings.

2. It is fuel-saving and labor-saving. For example, 1-1.5kg crop residues
are enough to cook a meal for a family of 3-5 people, with no need to add in
more fuel and no need to watch the stove.

3. It is of high thermal power and thermal efficiency, and the thermal power
is adjustable. It does use any electricity nor additives. The flame is
similar to the one from LPG, which can give relatively high thermal power.
5kg water can be heated to boiling within 5-8 minutes, for instance.

4. It is environment friendly, which is good to health. The stove combustion
chamber and flame path are both sealed, hence no smoke is emitted within the
house, and the outdoor smoke is little. Thus the smoke emission is reduced
and the air is cleaned, which is in favor of maintaining the CO2 balance and
mitigating the global greenhouse effect.

5. It is durable. All the parts that contact with fire, such as combustion
chamber, flame path and fuel entrance are made of cast iron, which are
flameproof and antioxidant.

6. It has a fuel entrance such that the fire can keep burning without
removing the cooker to add in fuel.

7. It is inexpensive and adapted to rural household usage.

8. It is small, light, and portable.

Currently, there are three models of cast iron biomass gasifier stoves:
round basic model, round cover high water encasement model, and cubic model.
New models can also be designed according to user's request. The round basic
model of 0.013m³ combustion chamber is the most popular model, and its price
is lowest. This product has been commercialized in China, and 70% of the
rural households in Luoyang city of Henan are using this product. It is also
exported to the Pacific country Vanuatu.

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