Wood Gasification Boiler Efficient, Economical, and Environmentally Responsible

jebatty Posted By jebatty, Feb 14, 2013 at 11:01 AM

  1. jebatty

    Minister of Fire 2.

    Jan 1, 2008
    Northern MN
    I prepared material for a conference yesterday. Here is an edited piece of that material that may be helpful to better understand why so many of us are quite passionate about gasification boilers.


    Purpose – to make you aware of a type of wood boiler (gasification)
    • that uses much less wood fuel than the more commonly known outdoor wood boiler (OWB).
    • that will not spew clouds of smoke and pollution around you or your neighbors.
    • that is practical to meet heating needs for a wide range of operations.
    • that can directly replace or supplement LP, fuel oil and natural gas boilers.

    What you will learn – with a wood gasification boiler –
    • Hot water heating with wood as the fuel is efficient, nearly smoke-free, and produces very little ash (ash also may be usable as a soil amendment).
    • Hot water heating with wood as the fuel is economical as compared to electricity, fuel oil, LP and other fossil fuels.
    • Hot water heating with wood as the fuel is environmentally responsible, uses a sustainable fuel resource, and is carbon neutral.
    • ... plus, use of wood as a fuel provides local jobs, supports the local economy, and further integrates your business into the community that supports you.

    What Is Wood Gasification as applied to a Wood Gasification Boiler?
    • Wood burned in firebox (about 400-550F): combustion releases 50-80% of heat content, plus smoke, particulates, aromatics, CO and H (wood gas).
    • Smoke, aromatics, CO and H (wood gas) directed by a draft fan into a secondary (ceramic) chamber, mixed with additional air (O2), superheated (1800-2000F), and completely combusted (98-99%), very little ash.
    • Superheated CO2, H20 vapor and non-combustibles directed by the draft fan through tubes (fire tubes) surrounded by water in the boiler and heat transferred to the water.
    • Low temperature CO2, H2O vapor and non-combustibles directed up the chimney.

    How Is a Wood Gasification Boiler Different from an Outdoor Wood Boiler?
    • Dry wood as a fuel vs green wood.
    • OWB – wood burned in firebox surrounded by water (water jacket), mostly low temperature (about 400-550F), heat transferred to water jacket, incomplete combustion, resulting smoke; the smoke contains a large quantity of non-combusted aromatics and wood gas; large amount of ash.
    • Gasification boiler – wood burned in firebox for heat and wood gas generation, secondary combustion chamber (1800-2000F) and fire tubes for heat transfer to water, complete combustion (98-99%), very little ash.

    What Is the Efficiency of a Wood Gasification Boiler?
    • Claims of manufacturers – inconsistent standards, laboratory test results, be skeptical.
    • Real world data and experience – 80% to 90% (using wood low heat value – LHV)

    How Economical Is Wood Use in a Wood Gasification Boiler as Compared to Fossil Fuels?
    • Energy (btu’s) in a pound of wood – 6,050 btu’s : 16.5 lbs = 100,000 btu’s = $0.75 @ $170.00/cord of red oak.
    • Energy in a kwh of electricity – 3,400 btu’s: 29.4 kwh = 100,000 btu’s = $3.11 @ $0.106/kwh.
    • Energy in a gallon of LP: 100,000 btu’s = $1.75
    • Comparison demonstration: bundle of wood.
    • Wood use usually is about 1/3 to 1/2 that of a traditional OWB.

    Why Is Wood as a Fuel Source Environmentally Responsible?
    • Trees produce wood; trees go through a natural cycle of growth (remove carbon from the atmosphere), and decay (release carbon to the atmosphere); burning wood is akin to decay that otherwise would occur naturally.
    • Trees are naturally self-sustaining (growth, decay, regrowth); forest management through best management practices can enhance tree growth and sustainable forests and trees.
    • Burning wood from trees does not add CO2 to the atmosphere, contrary to burning fossil fuels.
    • Trees and forest provide habitat for a wide range of birds, mammals, and other wildlife.
    • Trees and forests hold rainfall water on the land, allow the water to infiltrate into the soil to recharge aquifers, reduce erosion, filter out polluting nutrients, trap harmful chemicals in the soils, provide clean water for lakes, rivers, and fish, and provide clean drinking water.

    What Other Benefits Are Realized from Using Wood as a Heating Fuel?
    • Burning wood supports sustainable forests: trees and forests provide recreational activities and support the recreation and tourism industries: hunting, birding, fishing, camping, trail riding (ATV, snowmobile, hiking and horseback ).
    • Burning wood supports the forest products industry: provides jobs and local employment (foresters, loggers, truckers, firewood harvesters, mills); provides wood, wood products, and a myriad of other products and by-products
    • Burning wood helps to create and sustain an economy which in turn protects the environment upon which all life depends for health and well-being.
    Trex83, 711mhw and bioman like this.
  2. mole

    Member 2.

    Oct 23, 2008
    Western NY
    Jebatty, What's the conference theme, sustainable energy? That's a great summary and a great cause! It's amazing how few people are even aware that there are other types of wood boilers than the standard "outdoor" ones.
  3. jebatty

    Minister of Fire 2.

    Jan 1, 2008
    Northern MN
    Thanks for the good word. This was a conference on high tunnel agriculture. Expressed need was for heating to handle seasonal cold spells and to extend the growing season. As a conference in north central Minnesota, fire wood is abundant and inexpensive, and likely to remain so. Thus, wood gasification boilers as a heating source would be a very good fit for many high tunnel operations.
  4. DaveBP

    Minister of Fire 2.

    May 25, 2008
    SW Maine
    Does "high tunnel" mean greenhouse big enough to drive a tractor down through? As row crops with a hoop house over it?
  5. jebatty

    Minister of Fire 2.

    Jan 1, 2008
    Northern MN
    I suppose it could, or much smaller. Not my business. Just my goal to spread the culture of wood gasification for hot water heating.
  6. skfire

    Feeling the Heat 2.

    Nov 15, 2010
    Excellent..thank you.


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