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Gasification:A process common to all

biomass stoves

A presentation at the

2004 ETHOS meeting

Thomas B. Reed, Agua Das, and Paul S. Anderson

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Holistic Cooking

The Solution to World Cooking must beHOLISTIC and Tailored to each country

Must satisfy the cook

Must use locally available fuels

Must satisfy world needs

Must use local manufacturing

Must fit local customs

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Pyrolysis Cloud protects char

A Char particle (solid carbon) can neither burn norbe gasified while it is shrouded by outpouringpyrolysis gases and vapors from the interior of theraw biomass. It remains black.

Once pyrolysis is complete, then char can begin toglow, making possible the char gasification

process.

At very high heat inputs or turbulence, gasificationaround the particle edges causes simultaneous

pyrolysis and gasification SPG

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The Typical Yield Of Pyrolysis:

1/3 Char 1/3 Burnable Vapors/Tars

(condensable at ambient temp.)

1/3 Permanent Gases

(CO, CO2, H2, CH4, N2)

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The second part isCHAR gasification

C + O2 CO2 + Heat

Heat + CO2 + C

2COHeat +H2O +C CO+H2

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Cocurrent Gasification=air and

gas move the same direction PrimaryAir passes through non burning fuel to the

flame front

Air is available at the site of pyrolysis

Then vapors/tars will be burned by the air withhigh heat release rapidly pyrolyzing wood to char

Any hot combustion gases above 700C react

quickly with the freshly produced char via chargasification to produce low tar CO and H2 gasesavailable for secondary combustion.

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Threefold path to improved

stoves

Gasification Secondary combustion

Heat utilization

Improved stoves better separate and

accommodate the conflicting needs of thesethree vital functions of all solid fueledstoves.

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Gasification that is remotefrom the combustion of the gases

has existed for decades in severalformats, such as powering internal

combustion engines.

During WWII over a million vehicles were

powered by WOOD.

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WWII Gasifier Vehicles

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WWII GASIFIERS

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The gasification process can alsobe close-coupled to the

combustion process.

The gases are separated from solids

Provided with secondary air Provided with ignition

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The Turbo Stove

Th T b St

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Pot

PotSupport

SecondaryAir

JetsGas

PrimaryAir

Adjust

Flaming

Combustion

Charcoal

ForcedAir

The Turbo Stove

8

Insulation

3kW Forced Convection Wood-Gas Stove Module

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Comparative Stove Test

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Wood-Gas Stove Assembly

4 kW

1 kW

Insert Cooking Modules in Stove Counter

Power Supply Options PV-Solar Home System

Local electric supply

PV module

Car or motorcycle battery

Hand power

Thermo-electric generator Thermal - PV

Spring motor

Air Supply Options 12 V blower (1 watt)

steam ejector

bellows

inflatable tube

spring blowerAir Controls

Wood-Gas Stove assembly

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Savings of Fuel Wood With New Wood-Gas Stove

A Meal Cooked With:

Traditional Wood Fire StoveNew Wood-Gas Stove

10 X More Wood

.250 kg wood 2.5 kg wood

Fuel Savings

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Starting Point

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Kitchen with flue

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Turbo Stove in Kitchen

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Ward

Ward , Colorado

Three burner wood gas stove

Individually adjustable burnersRemovable tincanium fuel

magazines have lasted 3 years

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Gasification: A New Stove

Capability

Permits proper air fuel ratios premixing and the

CLEAN combustion this gives you.

More compact, lighter, and smaller than equivalentwood stoves (see the WoodGas Camp Stove)

Uses significantly less fuel than traditional stoves

Uses a wide variety of biomass fuels

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Gasifier Stove Options

Natural draft/forced draft Inverted downdraft/Top lit/Charcoal Making

Tar burning, char making

(downdraft=cocurrent)

Char burning, tar making

(updraft=countercurrent) Batch fed/ Continuous operating

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GASIFICATIONof biomass permits

(and works best) with

accurate AIR/FUEL ratiosand pre-mixing for clean

combustion.

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The science of gasifier stoves(and of all stoves)

requiresappropriate measurements

and abilities to regulated

the stoves

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THE DWYER GAUGE

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Pitot Tube and Gauge

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Creating gases separately also

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Creating gases separately also

facilitates additional uses, such asnew forms of lighting.

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Reading by wood gas light

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Paul Anderson Briquetting

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Bagasse Pellets

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Enjira Cooking in Ethiopia

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THE SIERRA STOVE

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TURBO TEA STOVE