[Gasification] Some Text on the Chinese Gasifier

Thu Nov 16 16:54:21 CST 2006

Dear All:

I note that there is no secondary combustion air supplied to the gas and 
stove.

I believe that one of the major advantages of a "hydrogen rich fuel" is 
that the burning velocity is so high and combustion limits so wide that 
there is no need to add the exact stoichiometric air as there is with 
most fuels. 

My memory is that my mother used manufactured gas during my childhood 
and there was no smell or need for ventilation in the kitchen.  I'm not 
sure whether air was added.  We regularly flare HRG without secondary 
air, and engine tuning is less critical.

TOM REED               BEF

Kevin Chisholm wrote:
> 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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