[Gasification] Some Text on the Chinese Gasifier

[Peter Singfield]

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.